JPH1038761A - Method for checking assembly of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for determining whether an internal combustion engine is assembled normally or not quickly and accurately. SOLUTION: Under a state where an exhaust side space 100 is closed and a crankshaft is rotated at a constant speed, pressures in the exhaust side space 100 and a surge tank 96 are detected by means of pressure sensors 106, 98 and an engine 90 is checked for the assembled state based on the pressure variation with time. The pressure variation with time is represented by the maximal value of each pressure and the crank angle when the maximal value is reached or the crank angle at a moment of time when the variation rate increases from a state where each pressure is constant. Based on these values, phase shift of a crank pulley or a cam pulley, insufficient valve clearance, missing of a compression ring, etc., can be determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an internal combustion engine assembly inspection method for inspecting the assembled state of an assembled internal combustion engine.

[0002]

2. Description of the Related Art At the time when assembly of an internal combustion engine (hereinafter simply referred to as an engine) is completed, no defective assembly such as a missing part of each part of the engine or a shift in operation timing between components has occurred. It is necessary for the engine to perform as designed. One inspection method for such an assembled engine is described in U.S. Pat. No. 5,355,713. This inspection method rotates the internal combustion engine without burning fuel,
This is to detect the presence or absence of a defective assembly by detecting the pressure waveform on the exhaust side or the intake side and comparing the detected pressure waveform with the corresponding pressure waveform of a normal internal combustion engine.
It is described that the comparison of the pressure waveforms is performed by comparing the characteristics of the pressure waveforms, and as the characteristics, it is described that the amplitude of at least one of the positive pressure pulse and the negative pressure pulse forming the pressure waveform is employed. ing. Further, in a normal internal combustion engine, the rotational phase of a crankshaft in which the pressure on the exhaust side exceeds a predetermined value (referred to as crank angle)
Describes that when the pressure on the exhaust side of the internal combustion engine to be inspected does not exceed the same value, a crankshaft assembly failure has occurred. That is, the inspection method of the internal combustion engine described in the above-mentioned U.S. Pat. This is a method of finding an assembly failure of the internal combustion engine by comparing with a specific value.

[0003]

Further, the above-mentioned U.S. Pat. No. 6,077,064 describes only that a defective assembly is detected on the basis of a pressure waveform on one of an exhaust side and an intake side of an internal combustion engine. It does not describe detecting an assembly failure based on the pressure waveforms on both the exhaust side and the intake side. Furthermore, if one type of assembly failure is found,
The inspection is to be terminated, so
When a plurality of types of assembly failures occur in one internal combustion engine, the plurality of types of assembly failures cannot be detected.

[0004] The present invention has been made in view of the above circumstances, and an object of the first invention according to claim 1 is to provide an internal combustion engine which is assembled by a method different from the method described in the above-mentioned US specification. It is an object of the present invention to make it possible to find a defective assembly of an engine. A second object of the present invention according to claim 2 is to select a pressure change state which is particularly suitable for detecting an assembly failure. An object of the present invention is to improve the reliability of an assembly failure inspection according to the present invention. Claim 4
A fourth object of the present invention is to provide an inspection method capable of detecting a plurality of types of assembly defects when one type of internal combustion engine has a plurality of types of assembly defects. A fifth object of the present invention is to provide an inspection method capable of detecting an assembly defect particularly likely to occur.

[0005]

Means for Solving the Problems, Functions and Effects of the Invention
In the first invention, the above problem is solved by a method of inspecting an assembly failure of an internal combustion engine by rotating an internal combustion engine having an intake valve and an exhaust valve, and by examining an intake side space and an exhaust valve communicating with the intake valve outside the intake valve. Detecting the occurrence timing of a predetermined change state of the pressure of at least one of the exhaust side space and the exhaust-side space communicating with the exhaust valve outside, and inspecting the assembly failure of the internal combustion engine based on the occurrence timing. Is solved by

The occurrence timing of a specific change state of the pressure in the intake space and the pressure in the exhaust space (hereinafter simply referred to as the intake pressure and the exhaust pressure, respectively) fluctuates with the linear reciprocating motion of the piston in the cylinder. And the timing at which the intake and exhaust valves open and close.
The pressure in the cylinder increases as the piston approaches the top dead center, and conversely, decreases as the piston approaches the bottom dead center. In the reciprocal engine, the exhaust valve starts to open first, and then the intake valve starts to open from the state where the intake and exhaust valves are closed. Then, after the exhaust valve is closed, the intake valve is closed. In this one cycle, for example, the time when the intake valve starts to open with the exhaust valve closed is closer to the time when the position of the piston in the cylinder is at the top dead center than in a normal internal combustion engine (when the crank angle is Small)
As the maximum value of the exhaust side pressure increases, the timing at which the maximum value is reached is delayed (the crank angle increases). Conversely, if it is far from the time at the top dead center, the maximum value of the exhaust-side pressure decreases and the time at which the maximum value is reached is earlier. Therefore, for example, if the timing at which the exhaust side pressure reaches the maximum value is known, the relative relationship between the crank angle and the opening / closing timing of the exhaust valve can be known. This indicates that a phase shift between the crankshaft and the camshaft has occurred due to a defective assembly. Also, for example, if the opening / closing timing of the exhaust valve changes relative to the crank angle, it affects the changing state of the intake side pressure. Can be detected. As described above, by knowing the occurrence time of the specific change state of at least one of the intake side pressure and the exhaust side pressure, it is possible to detect the occurrence of the assembly failure without disassembling the engine.

In the method of inspecting an assembly failure of an internal combustion engine according to the present invention, the detection of the assembly failure in consideration of the values of the intake side pressure and the exhaust side pressure in a specific change state is not excluded. For example, the exhaust pressure at the time when the exhaust valve starts to open, the maximum value of the exhaust pressure, or the like may be considered. Also, the internal combustion engine to be tested can be rotated by burning the fuel in itself, or it can be rotated in connection with another rotary drive. The former is called a firing inspection, and the latter is called a motoring inspection. In general, motoring is easier than firing. In order to perform the operation by the energy of the explosion of the engine itself, it takes time to supply the fuel and process the exhaust gas. Further, the acquired values of the intake side pressure and the exhaust side pressure contain more noise. When the engine is rotated by another rotary drive device, such a problem can be reduced, and the inspection of the assembled state can be performed more easily.

[0008] In the second invention, the above-mentioned problem is that the predetermined change state of the pressure in the first invention is changed when the exhaust-side pressure, which is the pressure in the exhaust-side space, reaches a maximum value. Exhaust-side pressure at which the exhaust-side pressure starts to decrease from the state in which the exhaust-side pressure starts to decrease from the state in which the pressure-maximum value is reached, the time when the exhaust-side pressure shifts from the decreasing state to the invariable state in which the exhaust-side pressure does not change with time. The decrease start time, the intake side pressure maximum value when the intake side pressure which is the pressure of the intake side space reaches the maximum value, and the time when the intake side pressure starts increasing from an unchanged state in which the intake side pressure does not change with time. This is achieved by including at least one of the intake pressure increase start timings. At each of the above-mentioned timings, the pressure change is abrupt, so that it is possible to accurately detect the occurrence timing of each pressure change state, and therefore, it is possible to detect an assembly failure with high reliability.

[0009] In the third invention, the above-mentioned problem is solved by the method for inspecting defective assembly according to the first or second invention, wherein at least a connection passage between an exhaust valve and an exhaust manifold and a connection passage between an intake valve and an intake manifold are provided. One of the problems is solved by closing one side and setting a space on the valve side from the closed position to at least one of the exhaust side space and the intake side space. The exhaust-side pressure and intake-side pressure can be detected without closing the connection passage between the exhaust valve and the exhaust manifold and the connection passage between the intake valve and the intake manifold. It is possible to clearly detect a change in the side pressure or the intake side pressure, accurately detect the occurrence time of the specific change state, and improve the reliability of the assembly failure inspection. The inspection in this mode is desirably performed before the exhaust manifold or the intake manifold is attached.

In the fourth invention, the above-mentioned problem is solved by the method of inspecting an assembly defect according to any one of the first to third inventions, when a plurality of types of assembly defects occur simultaneously in the internal combustion engine to be inspected. The problem is solved by including a step of detecting at least two types of assembly defects. When a plurality of types of assembly failures occur simultaneously in one internal combustion engine, the assembly failures have occurred, but the type cannot be specified, or one of the plurality of types of assembly failures is detected. In such a case, it is possible to display the presence of the defective assembly and end the inspection. However, by including the step of detecting at least two of a plurality of types of assembly defects as in the present invention, the presence of at least two assembly defects can be detected together. As described above, if it is determined that the type of assembly defect cannot be specified, it is necessary to disassemble the internal combustion engine to search for a defective portion, and if one of a plurality of types of assembly defects is detected, If the inspection is completed after indicating the existence of the assembly defect, the displayed assembly defect is corrected, another assembly defect inspection is performed, another assembly defect is detected, and the assembly defect is removed. In any case, it takes a long time to remove the defect. On the other hand, if at least two of a plurality of types of assembly defects can be detected, the at least two assembly defects can be removed together, and the time required for removing the assembly defects can be reduced. If all kinds of assembly defects can be detected together, all the assembly defects can be removed together, which is ideal. However, it is not essential that all the assembly failures can be specified, and it is beneficial if at least two can be specified, and it is more beneficial if three or more can be specified. In addition, if the types of assembling defects that may have occurred can be limited to a small number, the time required for finding a defective portion can be reduced.

According to a fifth aspect of the present invention, there is provided a method for inspecting defective assembly according to any one of the first to fourth aspects, wherein the defective assembly to be inspected is determined by a defective valve clearance of an intake valve and a defective valve clearance of an exhaust valve. And at least one of a phase shift between the crankshaft and the camshaft and a missing compression ring. As will be described later in the embodiment, by knowing the occurrence time of a specific change state of at least one of the intake side pressure and the exhaust side pressure, a valve clearance failure of the intake valve, a valve clearance failure of the exhaust valve, a crankshaft, and the like. It is also possible to inspect at once a plurality of phase shifts between the shaft and the camshaft and missing compression rings. These assembly failures are relatively likely to occur in actual assembly lines, and it is of great benefit that these inspections can be performed without disassembling the internal combustion engine.

[0012]

Preferred embodiments of the present invention can be carried out in the following embodiments in addition to the embodiments described in the claims. The embodiments are conveniently described as an embodiment of the same type as the claims. However, an embodiment that further depends on an embodiment that depends on a plurality of claims or implementations cannot necessarily read all of the plurality of claims or implementations, but can actually read the claims. Should be read only for (1) The exhaust-side space is a space composed of an exhaust valve chamber and a space in the exhaust manifold, and the pressure in the exhaust-side space is detected by closing an exhaust port of the exhaust manifold. , 4, 5. Since the opening and closing timings of the exhaust valves of the respective cylinders are shifted at equal intervals during one cycle, for example, if the pressure in a space (one location) consisting of the exhaust valve chamber and the space in the exhaust manifold is detected,
As described in an embodiment of the present invention described later, it is possible to determine at least whether or not an assembly failure has occurred. Since the inspection can be performed in a state where the exhaust manifold is assembled, it is easier to obtain the exhaust-side pressure of each cylinder than in the third embodiment. (2) The intake side space is a space inside a surge tank, wherein the intake side space is a space inside a surge tank.
5. The method for inspecting a defective assembly of an internal combustion engine according to any one of the first aspect. Since the opening / closing timing of the intake valve of each cylinder is shifted at equal intervals during one cycle, similarly to the opening / closing timing of the exhaust valve, the surge tank internal space is It is possible to determine whether or not assembly failure has occurred for each cylinder based on the pressure. The inspection in this mode can be performed in a state where the intake manifold and the surge tank are assembled, and the number of pressure sensors used is small, so that the intake side pressure can be easily obtained. (3) An assembly failure is determined by comparing the detected occurrence time of the predetermined change state with a preset reference occurrence time. 6. A method for inspecting a defective assembly of an internal combustion engine according to any one of the above. The reference generation time set in advance is, for example, a time actually measured in an engine in which each assembly defect does not occur, or a time scheduled for design. The phase shift of the crankshaft is
This is caused by a shift in the mounting phase of the crank pulley to the crankshaft or a shift in the meshing phase between the crank pulley and the timing belt, timing chain, or the like. Further, the phase shift of the camshaft is caused by the phase shift of the mounting of the cam pulley to the camshaft and the phase shift of the engagement between the cam pulley and the timing belt. This phase shift of the camshaft, as described later in the embodiment,
It may also be caused by a meshing phase shift between a drive gear attached to one of the intake camshaft driving the intake valve and an exhaust camshaft driving the exhaust valve, and a driven gear attached to the other. The magnitude of the effect of these assembly failures on the timing of occurrence of the specific change state of the exhaust side pressure and the intake side pressure is discontinuous. This is because the shift of the mounting phase or the meshing phase of the crank pulley or the like occurs stepwise. In addition, the magnitude of the effect of the lack of the compression ring on the occurrence time of the specific change state is discontinuous. Therefore, as a state in which these assembly failures do not occur, a result of detection performed on a normally assembled normally (preferably, a plurality of units, but may be one) is obtained. The timing of occurrence of the specific change state (hereinafter, simply referred to as a normal occurrence timing) itself can be set, and if the difference from the normal occurrence timing is within a certain range, it can be determined that there is no assembly failure in the engine. On the other hand, the state of occurrence of the poor valve clearance is continuous. For example, an exhaust valve is considered to be normal if its valve clearance is within a certain range. Therefore, the preset reference generation timing regarding the valve clearance of the exhaust valve is all the generation timings corresponding to the maximum value and the minimum value of the normal valve clearance. As described above, if the reference occurrence time is set as a reference that can distinguish between a case where each assembly defect has occurred and a case where it has not occurred, the actual occurrence time of the specific change state is defined as the reference occurrence time. By comparing, it is possible to quickly and easily specify which of the assembly failures has occurred. (4) The phase shift between the crankshaft and the camshaft includes at least one of a phase shift of the mounting of the crank pulley to the crankshaft, a phase shift of the mounting of the cam pulley to the camshaft, and a phase shift of the meshing of the pair of intake scissors gears. Item 5. The method for inspecting a defective assembly of an internal combustion engine according to any one of the items [1] to [3]. (5) At least one of the exhaust side pressure maximum value arrival time, the exhaust side pressure unchanged state transition time, the exhaust side pressure decrease start time, the intake side pressure maximum value arrival time, and the intake side pressure increase start time, and At least the reference exhaust side pressure maximum value arrival time as the reference change state, the reference exhaust side pressure non-change state transition time, the reference exhaust side pressure decrease start time, the reference intake side pressure maximum value arrival time, and the reference intake side pressure increase start time 3. An inferior assembly location of the internal combustion engine is estimated based on at least one of the direction and the magnitude of the difference from the one.
The method for inspecting a defective assembly of an internal combustion engine according to any one of the first to fifth embodiments. (6) A plurality of timings selected from the exhaust pressure maximum value reaching timing, the exhaust pressure non-change state transition timing, the exhaust pressure reduction start timing, the intake pressure maximum value reaching timing, and the intake pressure increase start timing 6. A method for estimating an assembly failure position of an internal combustion engine based on a combination of different ones of the plurality of times and a reference time as the reference change state of the plurality of times. The method for inspecting an assembly failure of an internal combustion engine according to any one of the first to third aspects. (7) There are a plurality of types of assembly failures to be inspected, and a specific pressure change state that is the specific change state of the pressure of at least one of the intake space and the exhaust space in response to the occurrence of the assembly failure. 6. A method according to claim 1, further comprising the step of specifying a defective assembly location based on the occurrence times of the plurality of types of specific pressure change states when a plurality of types are obtained. 7. The method for inspecting an assembly failure of an internal combustion engine according to any one of the above-described items. (8) When none of the plurality of types of specific pressure change states has occurred, it is determined that the internal combustion engine is normally assembled, and the execution of the assembly failure location specifying step is omitted. Item 7. The method for inspecting an assembly failure of an internal combustion engine according to Item 7. According to this aspect, it is possible to eliminate unnecessary execution of the assembling defective portion specifying step. (9) In the defective assembly location specifying step, among the plurality of types of specific pressure change states, the determination is made earlier for the second and subsequent ones having the smallest type of the corresponding defective assembly location. 9. The method for inspecting an assembly failure of an internal combustion engine according to claim 7 or 8. According to this aspect, when there is a possibility that a plurality of types of assembly failures may occur at the same time, it is easy to specify an assembly failure location. When it is clear that the time of occurrence of a particular pressure change state is not normal, the fewer types of assembly failure places corresponding to the specific pressure change state, the easier it is to identify the assembly failure places, and thereafter This is because the information of the identified defective assembly can be used to specify another defective assembly. (10) In the step of identifying a defective assembly location, if it is determined that the occurrence time is not normal among the plurality of types of specific pressure change states, the second or subsequent one is the easiest to confirm whether the determination is appropriate or not. 10. The method for inspecting a defective assembly of an internal combustion engine according to any one of claims 7 to 9, wherein the determination is made earlier than the above. If the determination is confirmed, the information of the result of the determination can be used for specifying a defective assembly portion thereafter. This method is easier to adopt as the confirmation of the appropriateness of the judgment is easier. (11) Among the plurality of types of specific pressure change states, in the assembling defect location specifying step, if it is determined that an assembling defect has occurred, the second and subsequent ones are the easiest to correct the assembling defect. Any one of embodiments 7 to 10, wherein the determination is made earlier.
6. A method for inspecting a defective assembly of an internal combustion engine according to any one of the above. If a plurality of types of assembly failures occur, by correcting some of them, the remaining assembly failure locations can be easily specified, or the unspecified assembly failure locations can be specified.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An engine assembly defect inspection method according to an embodiment common to the first to third inventions and the fifth invention will be described below together with an engine inspection apparatus suitable for carrying out the method. FIG. 1 shows a V-type six-cylinder DO as an example of an engine.
FIG. 2 is a perspective view showing a main operating portion of an HC gasoline engine (hereinafter, simply referred to as a V6 engine). In this type of engine, reciprocating motion in a cylinder (not shown) such as the pistons 10 and 12 is converted into rotational motion of the crankshaft 18 via the corresponding connecting rod 14, and the rotational force of the crankshaft 18 is used as power. It is taken out as outside. In order to continue the operation of the engine, a valve train including exhaust and intake valves is operated in association with the rotation angle of the crankshaft 18. Note that the piston 10 and the piston 12
The three pistons in each of the left and right banks of the V6 engine are shown as representative.

In the V6 engine of this embodiment, the crank pulley 2 attached to the crankshaft 18
0, timing belt 22, cam pulleys 24, 26 of the left and right banks, exhaust camshafts 28, 30, to which cam pulleys 24, 26 are respectively attached, intake camshafts 32, 34, and exhaust camshafts 28, 3.
0, drive gears 36, 38 respectively attached to
A camshaft rotation mechanism 44 is constituted by driven gears 40, 42 and the like attached to the intake-side camshafts 32, 34, respectively, as main components. Further, a valve train 52 is constituted by a plurality of cams 46 formed on each camshaft, and an exhaust valve 48 and an intake valve 50 which are opened and closed by their rotation as main elements.

When the crankshaft 18 is rotated, the exhaust valve 48 and the intake valve 50 operate via the crank pulley 20, the timing belt 22, the cam pulleys 24 and 26 of the left and right banks, and the exhaust camshafts 28 and 30. Let me do. Therefore, when the timing belt 22 becomes loose, the opening / closing timing of each valve fluctuates. To suppress this, a belt idler 54 having an auto tensioner (not shown) is provided. Further, belt idlers 56 and 58 without an auto tensioner are also attached. These belt idlers 54 to 58 are effective in increasing the number of meshing teeth of the timing belt 22, the crank pulley 20, and the cam pulleys 24 and 26. So-called scissor gears 60, 6 are provided on the intake side camshafts 32, 34, respectively.
2 are mounted so as to be relatively rotatable. The scissors gears 60 and 62 are combined with the driven gears 40 and 42, respectively, and are driven by spring members (not shown).
The drive gears are biased so as to rotate relative to the drive gear, so that the backlash of the engagement between the driven gears 40 and and the drive gears 36 and 38 is suppressed, and the noise of the engine is reduced.

The rotation angle of the crankshaft 18 and the opening / closing timing of each exhaust valve 48 and intake valve 50 are accurately associated with each other. Since the V6 engine as the engine to be inspected in the present embodiment is a 4-cycle gasoline engine, the number of teeth of the crank pulley 20 and the number of teeth of each of the cam pulleys 24 and 26 are set to 1: 2. The number of teeth of the crank pulley 20 is 24, and the number of teeth of each cam pulley is 48
It is a piece. The drive gears 36, 3
8 and the driven gears 40 and 42 have one to one teeth,
Each has 40 sheets.

When assembling the engine, the rotation angle of the crankshaft 18 and each of the exhaust valve 48 and the intake valve 5
It is important to match the opening and closing timings of the crank pulley 20 and the cam pulleys 24 and 26.
And the timing belt 22 are provided with marks for phase alignment, and these phase alignment marks are aligned so as to be assembled as shown in the enlarged portion of FIG. Drive gears 36, 38 and driven gears 40,
42 is the same. If this phase adjustment is not performed correctly, the rotation angle of the crankshaft 18
The relationship with the opening / closing timing of each valve is broken. For example,
As shown in the enlarged view of FIG. 2, the phase alignment mark between the crank pulley 20 and the timing belt 22 is shifted by one tooth, and as shown in the enlarged view of FIG. In this case, the relationship between the positions of the pistons 10 and 12 in the cylinder and the opening / closing timing of each valve is broken, and the opening / closing timing of each valve is changed by the rotation angle of the crankshaft 18 by 360/24 = 15 degrees. , 12 and so on.

The cam pulley 24 and the timing belt 22
As shown in the enlarged view of FIG. 2, when the cam pulley 24 is advanced by one tooth, the phase is shifted by one tooth (hereinafter, referred to as one cam pulley advanced), as shown in the enlarged view of FIG. The opening / closing timing of each valve advances by 360/48 = 7.5 degrees with respect to the positions of the pistons 10, 12, and the like. In addition, in a state where the drive gear 38 and the driven gear 42 are shifted by one tooth and the driven gear 42 is advanced by one tooth as shown in the enlarged view of FIG. 2 (hereinafter, referred to as a driven gear one tooth advanced), The opening / closing timing of each valve advances relative to the positions of the pistons 10 and 12 by 360/40 = 9 degrees in the rotation angle of the intake camshaft 34. The above-described phase misalignment has been exemplified only for one tooth advance of the cam pulley 20 and the like, but these may be delayed. It is extremely rare that lead / lag of two or more teeth occurs. The invention of the present application is such a 2
Although the present invention is applicable to advance / delay beyond a tooth, only one tooth advance / delay occurs in the following for the sake of simplicity. It should be noted that the structure of the portion where the crankshaft 18 and the crank pulley 20 are connected is generally configured so as not to be assembled with the relative phases shifted. Therefore, the relative phase between the crankshaft 18 and the crank pulley 20 does not always deviate even in the state where the one tooth of the crank pulley is advanced / delayed. The same applies to the relative phase between each exhaust-side camshaft and the cam pulley, and the relative phase between each intake-side camshaft and the driven gear.

In order for the engine to exhibit the expected performance, the rotation angle of the crankshaft 18 and the exhaust valves 4
8 and the opening / closing timing of the intake valve 50 must be in a relationship as designed. Therefore, in addition to the assembly alignment of the camshaft rotation mechanism 44 by the phase alignment mark, the rotation angles of the exhaust-side camshafts 28 and 30 constituting the valve train 52 and the corresponding exhaust valves 4
8 and the intake-side camshaft 3
The rotation angles 2 and 34 and the opening / closing timing of each corresponding intake valve 50 must be in a designed relationship.
These relationships depend on the valve clearance. Abnormal valve clearance due to poor engine assembly may be caused by a shim 72 having an incorrect thickness, a valve seat member 74 not being properly fitted to the cylinder head 76, or the like. What is valve clearance?
As shown in FIG. 3, this is the maximum clearance between the cam 46 and the shim 72 mounted between the lifter 70. For example, when the valve clearance is larger than that of a normal product, the timing of opening each valve is later than that of a normal product, and the timing of closing each valve is earlier. If the valve clearance is smaller than the normal product, the reverse is true.

Next, the crank pulley advance / delay,
The configuration of an engine inspection device for inspecting cam pulley advance / delay, driven gear advance / delay, and large / small valve clearance, as well as missing compression rings, will be described.

FIG. 4 is a conceptual diagram of the engine inspection apparatus of the present embodiment. Inspection target engine 90 to be inspected
(Only the left bank is shown for simplicity)
Attached to the cylinder head 76, the cylinder head 7
6 includes an intake manifold 94 provided in each of the left and right banks communicating with the intake port 92 of each cylinder inside the cylinder 6, and one surge tank 96 communicating with the two intake manifolds 94. The apparatus includes a pressure sensor 98 for measuring the pressure in the surge tank 96, an exhaust port 100 for each cylinder formed inside the cylinder head 76, and a masking member 102 attached to keep the outside airtight, Ring 104 used to more reliably maintain the pressure, a pressure sensor 106 for measuring the pressure inside the exhaust port 100, and an A / D converter including an amplifier for amplifying the output signals of the pressure sensors 98 and 106, respectively. 110 and 112, a crank angle sensor 114, and an inspection control device 119 as main components. It is.

The inspection controller 119 includes a microcomputer (not shown) and includes the above-described A / D converters 110 and 11.
2 and a determiner 117 for determining the assembly state of the engine based on signals from the crank angle sensor 114, and a display 118 for displaying the determination result of the determiner 117. The pressure sensor 98 that measures the pressure on the intake side is:
While one is mounted on the surge tank 96, the pressure sensor 106 for measuring the pressure on the exhaust side is mounted independently for each cylinder. Therefore, A / D converter 1
10 may be one, but the number of A / D converters 112 required is the same as the number of cylinders of the engine 90 to be inspected. As described above, in the present embodiment, the space inside the intake port 92, the intake manifold 94, and the surge tank 96 is the intake side space, the inside of the exhaust port 100 is the exhaust side space, and the exhaust side space is The portion of the exhaust port 100 that opens to the outside of the cylinder head 76 is closed as a closing position. Although the intake side space is not closed, the intake side space may be closed. Also, the intake port 9
2, or the space inside the intake port 92 and the intake manifold 94 can be used as the intake side space. In the former case, a pressure sensor 98 is required for each cylinder,
In the latter case, pressure sensors 98 are required by the number of intake manifolds 94.

The engine 90 to be inspected is fixed on a base 120 as shown in FIG.
22, is accurately rotated at a constant speed by a motor 125 connected to the crankshaft 18 via a drive shaft 124. The drive shaft 124 includes bearings 126 and 128
Supported by the two bearings 12
6, 128 and the motor 125 are fixed to the base 120. When the motor 125 is rotated by the inspection control device 119, the pressure sensors 98, 1
By detecting the fluctuation of the output of 06, the assembly state of the engine is inspected.

As described above, when the engine 90 to be inspected is rotated by the motor 125, each valve is opened and closed with a change in the crank angle. When the rotation speed of the motor 125 becomes constant and the pressure in each cylinder changes steadily, the output of each of the pressure sensors 98 and 106 (hereinafter simply referred to as the intake pressure P _IN and the exhaust pressure P _EX respectively) becomes
Assuming that the inspected engine 90 is a good one, the state changes as shown in FIG. FIG. 6 shows a change in a position of one piston, for example, the piston 10 in the cylinder (hereinafter, simply referred to as a piston position PP), an exhaust-side pressure P _{EX of} the piston, and a change of an intake-side pressure P _IN common to each piston. It is a thing. This piston 10 is simply called a piston #
No. 1. The engine 90 to be inspected is a V6 engine, and three pistons in the left bank are pistons # 1 and #
3, # 5, 3 pistons in right bank are piston # 2
(Corresponding to the piston 12), # 4, and # 6 are arranged in each bank in this order. When the V6 engine is rotated on its own by the explosion energy in the cylinder, it is exploded, for example, in the order of pistons # 1 to # 6.

First, the change in the exhaust side pressure P _EX will be described.
When the crankshaft 18 is rotated by the operation of the motor 125 and the crank angle θ _crank becomes the angle θ _EXopen , the exhaust valve 48 corresponding to the piston # 1 starts to open. At this time, the piston # 1 is moving toward the bottom dead center BDC, and the air in the exhaust port 100 starts to be sucked into the cylinder. Therefore, the exhaust pressure _{PEX which} has been a certain pressure starts to decrease. Note that this constant pressure is referred to as an exhaust-side pressure _invariable value P _EXconst . Also, the angle θ _EXdec equal to the crank angle θ _crank = θ _EXopen
It is referred to as the exhaust pressure decrease start angle. After the piston # 1 has passed through the bottom dead center BDC and the piston # 1 has been returned to the same position as when the exhaust valve 48 was opened, the air in the cylinder and the exhaust port 100 is compressed, so that the exhaust is performed. The side pressure P _EX starts to rise, and the crank angle θ _crank becomes θ
_When the intake valve 50 starts to open due to _INopen , the exhaust pressure maximum value P _EXmax is _reached . The crank angle θ _crank = θ _INopen at this time is _defined as the exhaust pressure maximum value reaching angle θ.
_{Called EXmax} . When the intake valve 50 is opened, when the crank angle θ _crank = θ _EXclose , the exhaust valve 48 is _closed.
Until is closed, the exhaust side pressure P _EX decreases sharply.
The crank angle θ _crank equal to this angle θ _EXclose is referred to as the exhaust-side pressure unchanged state transition angle θ _EXconst . During the period in which the exhaust valve 48 is closed, the exhaust side pressure P _EX becomes the exhaust side pressure _invariable value P _EXconst . Then, when the crank angle θ _crank further advances and _reaches θ _INclose , the intake valve 50 is closed. For convenience of the following description, the exhaust-side pressure maximum value P in the normal assembly state shown in FIG.
_With the magnitude of _EXmax being 100, other pressures are represented by relative values. For example, the exhaust-side pressure invariable value P in a normal assembly state
_EXconst is about 10. The rotation speed of the motor 125 is arbitrary, and the engine assembly inspection may be performed by changing the rotation speed as needed.

While the exhaust-side pressure P _EX is obtained independently for each cylinder, the intake-side pressure P _IN is obtained by one pressure sensor 98 as common data for all cylinders. In the example shown in FIG. 6, each intake valve 5 of pistons # 1 to # 6
Locations where the intake-side pressure P _IN has changed due to the state change of 0 are indicated by piston numbers # 1 to # 6. These six portions appear at regular intervals once in one cycle in which the crank angle θ _crank is 0 to 720 degrees. Hereinafter, a change in the intake-side pressure _PIN due to a change in the state of the intake valve 50 corresponding to the piston # 1 will be representatively described.

When the crank angle θ _crank becomes θ _INopen ,
Since the intake valve 50 starts to open, the compressed air in the cylinder and the exhaust port 100 flows to the intake manifold 94, and the pressure in the intake manifold 94 starts to increase. At this time, the air in the intake manifold 94 is being sucked into the cylinder corresponding to the piston # 6.
Since the outflow flow rate of the air from 0 is larger, the pressure in the intake manifold 94 starts to increase. The crank angle θ _crank at the start of the increase is referred to as an intake-side pressure increase start angle θ _INinc . Then, the position PP of the piston # 1
Near the point at which TDC reaches the top dead center TDC, the flow rate of air decreases due to a decrease in the pressure in the cylinder and the exhaust port 100 and a decrease in the valve clearance of the exhaust valve 48.
Since the intake flow rate of the piston # 6 into the cylinder is balanced and becomes smaller than the intake flow rate thereafter, a maximum value of the intake pressure P _IN appears. The crank angle theta _crank at this point is referred to as the intake side pressure maxima reaching angle theta _{Inma x.} After the position PP of the piston # 1 reaches the top dead center TDC, the increase in the cylinder volume of the piston # 1 also promotes the decrease of the intake pressure P _IN . The change in the intake-side pressure P _IN shown in FIG.
₍ every 120 degrees by _crank ).

[0028] Figure 7, when the inspection engine 90 is assembled properly, the change in the exhaust-side pressure P _EX and the crank reference signal obtained independently for each cylinder of the above, the crank angle theta _crank Is a graph showing the horizontal axis. The crank reference signal is output from the crank angle sensor 11.
4 is a pulse signal output twice in one cycle, that is, twice each time the crank angle θ _crank changes 720 degrees in the engine to be inspected 90 of the present embodiment. The crank angle sensor 114 of the engine 90 to be inspected according to the present embodiment is
And a pickup, such as an electromagnetic pickup, for detecting passage of the detected part formed at one place on the outer periphery of a timing rotor (not shown) integrally formed with the timing rotor. However, it is not essential that the crank angle sensor 114 be configured as described above in implementing the engine inspection method of the present invention. Most modern engines are provided with a sensor corresponding to the crank angle sensor 114, although the mounting locations are variously different. If such a sensor is not provided,
For example, the configuration may be such that a specific phase of the rotating crank pulley or crankshaft can be detected using a reflection type photoelectric switch or proximity switch. Exhaust side pressure P _EX
Is shifted by 120 degrees in crank angle θ _crank ,
Show almost the same change. This is a state in which none of the above-described crank pulley advance / delay, cam pulley advance / delay, driven gear advance / delay, large / small valve clearance, and lack of compression ring have occurred.

The determiner 117 includes a crank angle sensor 1
Measure the time interval of generation of the crank reference signal from 14,
It has a function of detecting that the rotation speed of the inspected engine 90 has become constant by making the time interval substantially constant. In addition, the A / D converter 11
0, 112, the pressure detection values of the pressure sensors 98, 106 are read, and the change state of the pressure detection values is analyzed.
Exhaust-side pressure _invariable value P _EXconst , start of depressurization of the exhaust-side pressure invariant value P _EXconst , exhaust-side pressure maximum value P _{EXconst
EXmax} , Exhaust side pressure P Exhaust side pressure _invariable value P of _EX
Transition to _EXconst, pressure boosting starting the intake pressure P _IN, the maximum value or the like of the intake pressure P _IN, detects the specific change in pressure conditions, a function of detecting the occurrence timing of their specific pressure changes state, a crank reference _Assuming that twice the signal generation time interval corresponds to the rotation angle of 720 degrees of the crankshaft 18, the crank angle θ _crank corresponding to the occurrence point of each specific pressure change state, that is, the exhaust side pressure decrease start angle θ _EXdec ,
Exhaust side pressure maximum value reaching angle θ _EXmax , Exhaust side pressure unchanged state transition angle θ _EXconst , Intake side pressure increase start angle θ _INinc ,
It has a function of specifying the intake side pressure maximum value reaching angle θ _{INmax and the} like. These functions are well-known as a waveform analysis technique, and the details thereof are not essential for understanding the present invention, so that detailed description will be omitted.

Next, when each of the above-mentioned assembly defects occurs,
Exhaust pressure P_EXOr intake side pressure P _INExplain the change in
You. In the following description, each of the above assembly failures may occur.
Pressure and crank angle values when
Is indicated with "". First, the intake valve
The poor valve clearance will be described. FIG.
Valve clear run of two intake valves 50 of one cylinder
The valve clearance is normal and one valve clearance
Exhaust pressure P when the pressure is small_EXGroup that shows the change of
It is rough. The solid line shows the intake valve clearance
Is normal, and the broken line indicates that the intake valve clearance is
It is small. The former is in the normal assembly state, the latter is the intake
It is called a lube clearance small state. Intake valve clearer
In the small state, the intake valve 50 starts opening early.
The exhaust-side pressure maximum value reaching angle θ_EXmax′ Is a normal group
Standing (θ_EXmax). Normal group
Exhaust in a standing state and a small intake valve clearance state
The difference between the maximum pressure reaching angle on the exhaust side and the maximum pressure reaching angle on the exhaust sideΓ
(= Θ_EXmax'-Θ_EXmax).

The exhaust-side pressure maximum value reaching angle difference Γ becomes smaller as the valve clearance becomes smaller as compared with the normal assembly state. In the small intake valve clearance state, the intake valve 50 starts to open earlier as described above, so that the pressure in the cylinder compressed by the piston becomes smaller than that in the normal assembly state, and the exhaust-side pressure maximum value P _{EXma of the} cylinder is reduced. _x 'is also the maximum value on the exhaust side pressure P _{EXmax in the} normally assembled state.
Than the exhaust-side pressure maximum value difference α. Further, since the exhaust-side pressure maximum value P _EXmax 'is small and the period from when one of the intake valves 50 is opened to when the exhaust valve 48 is closed is long, the exhaust-side pressure _invariable value P _EXconst ' is also normally assembled. It becomes smaller by the exhaust-side pressure _invariable value difference β than that in the state (P _EXconst ). In the example of FIG. 8, the air in the intake manifold 94 is sucked into the cylinder as the volume in the cylinder increases due to the movement of the piston, and the exhaust-side pressure _invariable value P _EXconst ′ becomes negative. . The exhaust-side pressure maximum value difference α and the exhaust-side pressure invariable value difference β also decrease as the valve clearance decreases, similarly to the exhaust-side pressure maximum value arrival angle difference Γ.

FIG. 9 shows two intake valves 5 of one cylinder.
7 is a graph showing the change in the exhaust-side pressure P _EX in a normal assembly state in which both valve clearances of 0 are normal and in a large intake valve clearance state in which one valve clearance is large. In this large intake valve clearance state, the intake valve 48 starts to open slowly by the exhaust side pressure maximum value reaching angle difference _、, so that the pressure in the cylinder becomes higher than in the normal intake valve clearance assembly state, and the exhaust side pressure maximum value P _EXmax ' _{Becomes larger} than the exhaust-side pressure maximum value P _EXmax by the exhaust-side pressure maximum value difference α. Further, since the exhaust-side pressure maximum value P _EXmax ′ is large and the period from when one of the intake valves 50 is opened to when the exhaust valve 48 is closed is short, the exhaust-side pressure _invariable value P _EXconst ′ is also P
_{It becomes larger} by the exhaust-side pressure _invariable value difference β compared to _EXconst .

FIG. 10 is a graph showing changes in the intake pressure P _{IN in} a normal assembly state, a small intake valve clearance state, and a large intake valve clearance state with respect to a change in the crank angle θ _crank . In response to a change in the timing at which one of the two intake valves 50 of the piston # 1 is opened, the intake-side pressure maximum value reaching angle θ _INmax ′, which is the crank angle at which the intake-side pressure P _IN is maximized, is normally assembled. Has changed with respect to that of. This change is represented by the intake-side pressure maximum value arrival angle difference Λ. The intake-side pressure increases start angle a crank angle intake pressure P _IN starts to increase θ _INinc '
Also shows the same change as the intake-side pressure maximum value arrival angle difference Λ.
This change is represented by the intake-side pressure increase start angle difference Ψ. The intake-side pressure maximum value arrival angle difference Λ and the intake-side pressure increase start angle difference Ψ also become smaller (larger) as the valve clearance becomes smaller (larger), like the exhaust-side pressure maximum value arrival angle difference Γ.

Next, defective valve clearance of the exhaust valve will be described. FIG. 11 is a graph showing a change in the exhaust-side pressure P _EX between a case where the exhaust valve 48 is in a normal assembly state and a case where one of the two exhaust valves 48 is in a state where the exhaust valve clearance is small. In the small exhaust clearance state, one of the exhaust valves 48 starts to open earlier, so that the exhaust side pressure decrease start angle θ _EXdec ′ becomes smaller than that in the normal assembly state. This shift is indicated by the exhaust-side pressure decrease start angle difference Φ in FIG. In addition, the exhaust valve 48, which starts to open earlier, is completely closed later than in the normally assembled state. This is indicated by an exhaust-side pressure unchanged state transition angle difference Σ. The magnitude of the exhaust side pressure decrease start angle difference Φ and the exhaust side pressure unchanged state transition angle difference Σ are
The values are almost the same. Since the timing at which the exhaust valve 48 is closed is late, the exhaust-side pressure _invariable value P _{EX const} 'becomes smaller by the exhaust-side pressure invariable value difference β, and the amount of air sealed in the exhaust port 100 is small. The pressure maximum value P _EXmax ′ is smaller than that in the normal assembly state by the exhaust-side pressure maximum value difference α.

FIGS. 12A and 12B show a case where a normal assembly state is obtained and a case where 2
7 is a graph showing a change in the exhaust-side pressure P _EX when one of the two exhaust valves is in a large exhaust clearance state. In this case, one of the exhaust valves 48 in the large exhaust clearance state is slower to start opening than the other and is quickly closed completely, but the opening and closing of the other exhaust valve is normal. Since it is performed at the same time as the assembled state, the exhaust-side pressure decrease start angle θ _EXdec ', the exhaust-side pressure maximum value reaching angle θ _EXmax ', and the exhaust-side pressure unchanged state transition angle θ _EXconst 'are almost the same as those in the normal assembled state. Is the same. However, since one of the exhaust valves 48 in the large exhaust clearance state closes quickly, the exhaust-side pressure _invariable value P _EXconst ′ increases, and the amount of air sealed in the exhaust port 100 increases. The maximum value P _EXmax ′ also increases. The abnormality in the valve clearance of the exhaust valve hardly affects the intake-side pressure increase start angle θ _INinc or the intake-side pressure maximum value reaching angle θ _INmax .

Next, the missing compression ring will be described. As shown in FIG. 4, the piston ring 134 includes a top ring 136, a second ring 138, and an oil ring 140. Among them, the top ring 136 and the second ring 138 are compression rings 144 that are important parts for maintaining airtightness between the piston and the cylinder and ensuring engine performance.
Is configured. Top ring 136 and second ring 13
If the at least one missing the 8, since the airtight holding function is decreased, the absolute value of the exhaust side pressure P _EX decreases as compared with the case where properly installed, whereas the exhaust side pressure maxima arrival angle θ _EXmax ', exhaust pressure immutable state transition angle θ _EXconst' is like hardly change their normal assembled condition. FIG. 13 is a graph showing a change in the exhaust-side pressure P _EX between the case where the assembly is in a normal assembly state and the case where one of the top ring 136 and the second ring 138 is missing. In the latter case, the exhaust pressure maximum value P _EXmax ′ is smaller by the exhaust pressure maximum value difference α. In a state where both the top ring 136 and the second ring 138 are missing, the above-described exhaust side pressure P _EX is further reduced, so that such an assembly failure can be detected. However, such a test is virtually unnecessary if at least one is missing, since the engine must be disassembled, modified and reassembled.

Next, the influence of the advance / delay of the cam pulley and the advance / delay of the crank pulley will be described. FIGS. 14 and 15 are graphs showing changes in the exhaust-side pressure P _EX corresponding to each piston in a state where the cam pulley 26 in the right bank is advanced by one tooth of the cam pulley and delayed by one tooth of the cam pulley, respectively. In these figures, the exhaust-side pressure decrease start angle θ _EXdec ′, the exhaust-side pressure maximum value arrival angle θ _EXmax ′, and the exhaust-side pressure unchanged state transition angle θ _EXconst of the cylinder whose corresponding piston number is an even number ′
Etc. are shifted with respect to those in the normal assembly state. In this way, the cam pulley of only one of the left and right banks advances /
In the state where the delay abnormality has occurred, the exhaust-side pressure maximum value reaching angle θ _EXmax ′ and the like of the cylinder having the odd or even piston number all change.

When the advance / delay of the crank pulley occurs, the change is the same as when the advance or delay of the cam pulley occurs simultaneously in both the left and right banks. However, the effect of the crank pulley advance is opposite to the effect of the simultaneous advance of the left and right cam pulleys, and is the same as the simultaneous delay of the left and right cam pulleys. Specifically, when a delay of one tooth of the crank pulley occurs, the exhaust-side pressures P _EX of all the cylinders change in the same manner as the exhaust-side pressures P _EX of the cylinders having even-numbered piston numbers shown in FIG. Show. When the advance of one tooth of the crank pulley occurs, the exhaust-side pressure P _EX of all the cylinders shows the same change as the exhaust-side pressure P _EX of the cylinder whose piston number is an even number shown in FIG. In addition, when the crank pulley advances or delays, the values such as the exhaust-side pressure decrease start angle θ _EXdec ', the exhaust-side pressure maximum value reaching angle θ _EXmax ', and the exhaust-side pressure unchanged state transition angle θ _EXconst ' Each change is the same as the change when the cam pulley delay or advance occurs simultaneously in both the left and right banks.

It should be noted that the cam pulley in the right bank advances one tooth /
In the case of delay, advance / delay of one tooth of crank pulley,
The intake pressure P _IN changes as shown in FIG. In this drawing, in the case of one cam lead / lag of the right cam pulley,
The intake pressure P _IN of the cylinder having an even piston number is shifted from the normal assembly state. On the other hand, when the crank pulley is advanced / delayed by one tooth, the intake pressures P _IN of all the cylinders are shifted.

FIG. 17 shows the exhaust-side pressure P when the crank pulley is delayed by one tooth or the cam pulley is advanced by one tooth.
₉ is a graph showing an example of a change in _EX . However, in the latter case, it is the exhaust-side pressure P _EX of the cylinder included in the bank where the cam pulley advances by one tooth. In this case, the exhaust side pressure decrease start angle θ _EXdec ′, the exhaust side pressure maximum value reaching angle θ _EXmax ′, and the exhaust side pressure unchanged state transition angle θ
_EXconst ′ is those in normal assembly state θ _EXdec , θ _EXmax
And θ _EXconst are _smaller by the exhaust-side pressure decrease start angle difference Φ, the exhaust-side pressure maximum value arrival angle difference Γ, and the exhaust-side pressure unchanged state transition angle difference Σ, respectively. The values of the exhaust-side pressure decrease start angle difference Φ, the exhaust-side pressure maximum value arrival angle difference Γ, and the exhaust-side pressure unchanged state transition angle difference Σ have substantially the same magnitude. In this case, the timing at which the intake valve 50 starts to open is earlier than in the normal assembly state. Therefore, as is clear from FIG. 6, the position of the piston starts to open at a position closer to the bottom dead center BDC as compared with the normal assembly state, and the exhaust-side pressure maximum value P _EXmax ′ is different from the exhaust-side pressure maximum value difference α. Only smaller. On the other hand, the exhaust-side pressure invariant value P _EXconst ′ does not become smaller than the exhaust-side pressure maximum value P _EXmax ′, but becomes almost the same as the normal assembled state.

When the cam pulley advances by one tooth, the magnitude of the exhaust pressure maximum value reaching angle difference Γ or the like becomes an angle corresponding to one tooth of the cam pulleys 24 and 26. That is, the rotation angle of the cam pulleys 24 and 26 is 360 degrees / 48 sheets = 7.5.
This angle is the angle of the crank pulley 20
This corresponds to a rotation angle of 5 degrees. On the other hand, the crank pulley 20
, The magnitude of the exhaust-side pressure maximum value arrival angle difference Γ, etc., is determined by the rotation angle of the crank pulley 20.
60 degrees / 24 sheets = 15 degrees smaller value. in this way,
For example, when the right cam pulley 26 has advanced one tooth,
The fact that one tooth delay has occurred in the crank pulley 20 is substantially the same for the cylinders in the right bank, and the exhaust pressure maximum value P _EXmax ',
The exhaust-side pressure maximum value arrival angle difference Γ and the like are substantially the same.

If the crank pulley is advanced by one tooth or the cam pulley is delayed by one tooth, the start time of compression by the piston (included in the bank where it occurs in the latter) is relative to the normal assembly state. As shown in FIG. 18, the exhaust-side pressure decrease start angle θ _EXdec ',
The exhaust-side pressure maximum value reaching angle θ _EXmax ′ and the exhaust-side pressure unchanged state transition angle θ _EXconst ′ are those in the normal assembly state.
_EXdec , _θEXmax, and _θEXconst are larger values by the exhaust-side pressure decrease start angle difference Φ, the exhaust-side pressure maximum value arrival angle difference Γ, and the exhaust-side pressure unchanged state transition angle difference Σ, respectively. The values of the exhaust-side pressure decrease start angle difference Φ, the exhaust-side pressure maximum value arrival angle difference Γ, and the exhaust-side pressure unchanged state transition angle difference Σ have substantially the same magnitude. The timing at which the intake valve 50 starts to open is delayed compared to the normal assembly state. Therefore, as apparent from FIG. 6, the position of the piston starts to open at a position closer to the top dead center TDC as compared with the normal assembly state, and the exhaust-side pressure maximum value P _EXmax ′ is different from the exhaust-side pressure maximum value difference α. Just get bigger. On the other hand, the exhaust side pressure invariable value P _EXconst 'exhaust side pressure maximal value P _EXmax' does not increase like a, substantially the same size as the normal assembled condition.

The magnitude of the exhaust-side pressure maximum value arrival angle difference Γ or the like depends on the above-described crank pulley 1 tooth delay or cam pulley 1
Similarly to the case where the tooth advance occurs, the rotation angle of the cam pulleys 24 and 26 is set to 360 degrees / 48 sheets = 7.5 degrees, or the rotation angle of the crank pulley 20 is set to 360 degrees / 24 sheets = 15 degrees. For example, the occurrence of one tooth delay in the right cam pulley 26 and the occurrence of one tooth advance in the crank pulley 20 are substantially the same for the cylinders in the right bank, and are the same for the cylinders included in the right bank. Exhaust pressure maximum P
_EXmax ', the exhaust-side pressure maximum value arrival angle difference Γ, etc. are substantially the same.

Next, the influence of the driven gear advance / delay will be described. 19 and FIG. 20 is a graph showing changes in the exhaust pressure P _EX of each cylinder when the right driven gear one tooth lead / lag occurs respectively with the crank reference signal. As is apparent from these graphs, the change in the exhaust pressure _PEX of the piston included in the right bank is different from that in the normal assembly state. Details will be described later. When the right driven gear advances or delays by one tooth, the intake pressure P _IN also changes as shown in FIG. As is apparent from this figure, when the right driven gear is advanced by one tooth,
Even though it is indicated by an even number, the intake-side pressure maximum value reaching angle θ
_INmax and the intake-side pressure increase start angle θ _INinc have smaller values than those in the normal assembly state. If the right driven gear is one tooth behind, on the other hand, the intake-side pressure maximum value reaching angle θ _INmax becomes larger than in the normal assembly state. When the left driven gear has one tooth advanced / delayed, the intake pressure P _IN changes for the cylinder having an odd piston number.

FIG. 22 is a graph showing the change in the exhaust pressure _PEX of the cylinders included in the right bank between the normal assembly state and the case where the right driven gear advances by one tooth. The driven gear 42 determines the opening / closing timing of the intake valve 50 of the right bank. Since the driven gear advances by one tooth, the exhaust-side pressure maximum value reaching angle θ _EXmax ′ is one of the driven gear 42.
The value becomes smaller by the angle corresponding to the tooth. In the present embodiment, since the number of teeth of the driven gears 40 and 42 is 40, the rotation angle of the driven gear 42 is 360 degrees / 40.
Sheet = about 9 degrees. This angle corresponds to a rotation angle of the crank pulley 20 of 18 degrees. With this angle change,
The exhaust-side pressure maximum value P _EXmax ′ and the exhaust-side pressure invariant value P _EXconst ′ _decrease by the exhaust-side pressure maximum value difference α and the exhaust-side pressure invariant value difference β, respectively. Further, the exhaust-side pressure unchanged state transition angle θ _EXconst ′ becomes smaller than the exhaust-side pressure unchanged state transition angle θ _EXconst in the normal assembly state by the exhaust-side pressure unchanged state transition angle difference Σ. Normally, the exhaust-side pressure unchanged state transition angle θ _EXconst is determined by the timing at which the exhaust valve 48 closes. However, when the driven gear advances one tooth, the exhaust-side pressure maximum value reaching angle θ
Since _EXmax 'is low because the exhaust pressure P _EX before the exhaust valve 48 is closed to reach equilibrium.

FIG. 23 is a graph showing changes in the exhaust pressure _PEX of the cylinders included in the right bank when the vehicle is normally assembled and when the right driven gear is delayed by one tooth. In this case, contrary to the case shown in FIG. 22, the exhaust-side pressure maximum value reaching angle θ _EXmax ′ is the exhaust-side pressure maximum value reaching angle difference Γ.
Only in the normal assembly state. Note that the magnitude of the transition angle θ _EXconst ′ of the exhaust-side pressure unchanged state and the magnitude of the transition angle difference Σ of the exhaust-side pressure unchanged state do not change.
With the change in the exhaust-side pressure maximum value reaching angle θ _EXmax ′, the exhaust-side pressure maximum value P _EXmax ′ and the exhaust-side pressure non-change value P _EXconst ′ become the exhaust-side pressure maximum value difference α and the exhaust-side pressure It increases by the change value difference β.

FIG. 24 shows the exhaust-side pressure maximum value arrival angle difference Γ, the exhaust-side pressure unchanged state transition angle difference Σ, and the exhaust-side pressure maximum value when only one of the various types of assembly failure described above occurs. This shows an example of values such as the difference α and the exhaust-side pressure invariable value difference β. In FIG. 24, the value of each pressure difference is
As described above, the exhaust-side pressure maximum value P in the normal assembly state
It is represented by a relative value with _EXmax being 100, and is measured based on a crank reference signal output by the crank angle sensor 114. In addition, in the case where the advance / delay of one crank pulley occurs, the respective values for both the left and right banks indicate the same magnitude, whereas in the case of advance / delay of one tooth of the cam pulley and advance / delay of one driven gear. Indicates that the pressure and angle of only the bank on which it occurred changes. Although very rare, the advance / delay of one tooth of the cam pulley or the advance / delay of one tooth of the driven gear may occur in both the left and right banks. The values when the intake-side valve clearance and the exhaust-side valve clearance are too small or too large change continuously according to the size of the clearance. The values in FIG. 24 indicate that the clearance is too small or too large. This is just an example of a value that can be detected.

FIG. 25 shows an R (not shown) in the decision unit 117.
9 is a flowchart illustrating an example of a main process of an assembly state inspection program stored in the OM and executed by the CPU and the RAM. In this main process,
The presence or absence of assembly failure is checked based on the value of the exhaust-side maximum pressure value P _EXmax corresponding to each of the pistons # 1 to # 6 of the engine 90 to be inspected. A display indicating that the inspection has passed is displayed in FIG. 26). If there is an assembly failure portion, the failure portion is estimated, and then based on the estimation result, a display indicating the inspection failure is displayed on the display 118. And a display indicating the defective portion.

First, in step 100 (hereinafter simply referred to as S100; the same applies to other steps), the flag variable f
lag is initialized to 0x00 (that is, 00000000), and in subsequent S102, the variable count is initialized to zero. Then, in S104, zero corresponding to piston # 1 is substituted for a variable i. The value obtained by adding 1 to the value of the variable i indicates the piston number. Next, S10
In 6, the exhaust-side pressure maximum value difference α [i], the exhaust-side pressure invariable value difference β [i], the exhaust-side pressure maximum value arrival angle difference Γ [i], and the exhaust-side pressure invariable of the (i + 1) th piston The absolute values of the state transition angle difference Σ [i], the exhaust side pressure decrease start angle difference Φ [i], the intake side pressure maximum value arrival angle difference Λ [i], and the intake side pressure increase start angle difference Ψ [i] are all It is determined whether it is less than 3 and if the result is NO, the variable c
After the value of "out" has been incremented,
If S, the value of the variable i is directly 5 in S110.
It is determined whether it is equal to (corresponding to piston # 6), and if not 5, 1 is added to the value of the variable i in S111, and the processing from S106 is repeated.

In step S106, the exhaust pressure maximum value difference α
[I], the absolute value of the exhaust-side pressure invariable value difference β [i]
The comparison with No. 3 is based on the assumption that only one assembly failure has occurred, as is apparent from FIG.
This is because if the absolute value of the exhaust-side maximum pressure difference α or the like is less than 3, the engine to be inspected 90 can be said to be in a normal assembled state. If the determination result in S110 is YES, it is determined whether the value of the variable count is equal to 0 in S112, and if the result is YES, S114
Then, after the process of displaying on the display 118 that the inspection has passed is performed, the main process ends. If the determination result in S112 is NO, it means that the inspection target engine 90 has failed the inspection, and in S116, the display 1
After the processing for displaying the indication of the inspection failure at 18 is executed, at S118, a subroutine for defective portion estimation processing is executed, and based on the estimation result, S120 is executed.
In, the display lamp corresponding to the estimated defective portion of the display 118 is turned on, and the main processing ends.

As the display 118, for example, FIG.
6 can be used. In FIG. 26, 200
Indicates an OK lamp that is turned on when the inspection result is passed. Reference numeral 202 denotes an NG lamp that is turned on when the inspection fails. If the inspection result is unsuccessful, the following lamp group indicating the content is turned on. That is, crank pulley advance ramp 204, crank pulley delay ramp 206, left bank cam pulley advance ramp 2
08, left bank cam pulley delay ramp 210, right bank cam pulley advance ramp 212, right bank cam pulley delay ramp 214, left bank driven gear advance ramp 216, left bank driven gear delay ramp 218,
A right bank driven gear advance lamp 220, a right bank driven gear delay lamp 222, and a small intake valve clearance lamp 224, a large intake valve clearance lamp 226, a small exhaust valve clearance lamp 228, and a large exhaust valve clearance lamp for each piston number. Each of the lamps 230 and the compression ring missing lamp 232 can be turned on independently. Further, as described later, when the inspection result is unclear, the lamp of the unclear part may be blinked. These lamp groups indicating defective assembly locations are referred to as defective-assembly location display lamp groups.

FIG. 27 is a flow chart showing an example of the content of the defective portion estimation processing shown in S118 of FIG. Note that the failure location estimation processing in the present embodiment is configured based on the assumption that even if an assembly failure has occurred, there is only one failure. In general terms, multiple assembly failures can occur simultaneously for one engine,
In practice it is very rare. Therefore, in most cases, the defective assembly portion can be specified by executing the defective portion estimation routine. Also, even if a plurality of assembly failures occur at the same time, and as a result, an error occurs in the determination result of the failure location estimation processing, the engine of the assembly failure is not determined to be a normally assembled engine. That error is acceptable.

In this defective portion estimation routine, first,
At S200, a flag indicating the presence or absence of each of the above-described assembly defects is provided.
0x00 is set (cleared to zero). these
The flags are collectively referred to as defective location flags. In this embodiment
The defective portion flag is set to 8 as shown in FIG.
One byte data, and these values are
If all are 0x00, it indicates that there is no defective assembly.
flag_drvnAnd flag_camMeans that the lower 4 bits are left
Driven gear advance / delay and cam pulley in right bank
Defective location flag indicating whether advance / delay has occurred
is there. Defective location flag flag_crnkIs the lower 2 bits
Indicates the presence / absence of advance / delay of the crank pulley. Also, fla
g_ins, Flag_inl, Flag_exs, Flag_exl,
flag _ringIs small intake valve clearance, intake valve
Large clearance, small exhaust valve clearance, exhaust valve
Lube clearance large, compression ring missing
The lower 6 bits corresponding to each cylinder
This is a defective portion flag indicated by the status of the unit. In addition,
The most significant bit of each defect flag indicates the possibility of error.
Bits, each of which may have a defective assembly
"1" if there is no reliable
Is the bit

Following S200, S202 to S21
At 4, the crank pulley inspection for setting the value of the defective portion flag flag _crnk (S202), the _cam pulley and driven gear inspection for setting the values of flag _cam and flag _drvn 1, 2 (S206, S210), and flag
Valve clearance and compression ring missing inspection for setting each value of g _ins , flag _inl , flag _exs , flag _exl and flag _ring (S214)
Are respectively executed. Hereinafter, their contents will be described. These inspections are exclusively executed by the respective determination processes of S204, S208, and S212. That is, if at least one defective assembly point is found in each of the above inspection processes, the defective portion estimation process ends at that point. This means that the above-mentioned assembly failure is 1
This corresponds to the assumption that there is only a part.

First, the inspection of the crank pulley will be described. FIG. 29 is a flowchart showing the contents of a subroutine crank pulley inspection routine. First, S
At 300, the exhaust-side pressure maximum value difference α [i] of all cylinders
Are all 3 or more, and the result is YES
If so, in step S302, the defective portion flag
_The crank pulley inspection is completed by setting 0x01 indicating _crnk pulley one tooth advance to _crnk . If the determination result in S300 is NO, it is determined in S304 whether or not the exhaust-side maximum pressure value difference α [i] of all the cylinders is -3 or less.
0x02 indicating the delay of one tooth of the crank pulley in lag _{cr nk}
Is set, and if NO, the crank pulley inspection processing ends directly. In S300 and S304, the reason why the exhaust-side pressure maximum value difference α [i] of all cylinders is compared with 3 or -3 is the same as that described in S106 of FIG. Here, not only the absolute value of the exhaust-side maximum pressure difference α [i], but also the sign is used to check the advance / delay of the crank pulley. S3
If the determination result of step 04 is NO, it means that the crank pulley is in a normal assembly state, and the defective portion flag fl
g _crnk remains (0x00) as it is cleared in S200 of FIG. Therefore, only in this case, S2
The result of the determination in step 04 becomes YES, and the processing after step S206 is executed. In the determinations in S300 and S304 described above, a detection result of a change in the occurrence timing of a specific pressure change state, such as the exhaust-side pressure maximum value arrival angle difference Γ, may be taken into consideration.

FIG. 30 is a flowchart showing the contents of the cam pulley and driven gear inspection 1 in S206 of the defective portion estimation processing shown in FIG. This process is to check whether the cam pulley and the driven gear advance by one tooth. First, in S400, it is determined whether or not the exhaust-side pressure maximum value differences α of all the cylinders in the left bank are equal to or smaller than −3. Is determined to be -16.5 or less. If the result is YES, S4
At 04, 0x01 is set to the defective portion flag flag _drvn indicating the advance of the driven gear of the left bank by 1 tooth. If NO, after 0x01 is set to the defective portion flag flag _cam at 1406 to indicate the advance of the _cam pulley of the left bank by 1 tooth at S406. , Cam pulley and driven gear inspection 1 is completed. The reason why the exhaust-side maximum pressure difference α [i] is compared with 3 or −3 in S400 and S408 is the same as that described in S300 and S304 in FIG. However, here, it is used not for the inspection of the crank pulley but for the inspection of the cam pulley and the driven gear. Therefore, the exhaust-side maximum pressure difference α [i]
Is obtained for all the cylinders included in each bank for each of the left and right banks. Step S402 is a process for determining which of the cam pulley and the driven gear is advanced by one tooth. The two values of the exhaust-side pressure maximum value arrival angle difference Γ shown in FIG. 24 (that is, -15 and -18)
Is determined with the intermediate value of the threshold value as the threshold value. Similarly, in other determination processing, the value serving as the threshold value for determination is determined by classifying the value of the exhaust-side pressure maximum value arrival angle difference Γ used for determination using the threshold value. It is adjusted so that the defective part can be estimated.

If the decision result in S400 is NO, S4
08 to S414, the above-mentioned S
The same processing as in steps S400 to S406 is performed. However,
0x08 indicating an advance driven gear 1 tooth of the right bank failure location flag flag _DRVn in S412 is set, is 0x01 is set indicating an advance cam pulley 1 tooth of the right bank S414 in defective portion flag flag _cam. On the other hand, if the determination result in S408 is NO, it is determined that the cam pulley and the driven gear are not at least one tooth advanced, and the first cam pulley and driven gear test 1 is ended. In this case, the result of the determination in S208 is YES, and the processing from S210 is executed.

FIG. 31 is a flowchart showing the contents of the cam pulley and driven gear inspection 2 in S210 of the defective portion estimation processing shown in FIG. This process
This is to check whether there is one tooth delay between the cam pulley and the driven gear. First, in S500, it is determined whether or not the exhaust-side pressure maximum value difference α of all cylinders in the left bank is 3 or more. If the result is YES, in S502, the exhaust-side pressure maximum value arrival angle difference Γ is determined. It is determined whether it is 16.5 or more. If the result is YES, S50
4 0x02 indicating a driven gear one tooth behind the left bank is set to the defective portion flag flag _DRVn, if the result is NO, i.e., after the 0x02 indicating a cam pulley 1 tooth delay of the left bank is set to the defective portion flag flag _cam in S506 , Cam pulley and driven gear inspection 2 is completed. Step S502 is a process of determining which of the cam pulley and the driven gear is advanced by one tooth.

If the decision result in S500 is NO, S5
08 to S514, the above-described S
The same processing as in steps 500 to S506 is performed. However,
In S512, 0x10 indicating a delay of one tooth of the driven gear in the right bank is set in the defective point flag flag _drvn , and in S514, 0x08 indicating a advance of one tooth of the _{cam pulley} in the right bank is set in the defective point flag flag _cam . On the other hand, if the determination result in S508 is NO, it is determined that the cam pulley and the driven gear are in the normal assembly state, and the inspection 2 of the cam pulley and the driven gear directly ends. In this case, the determination result in S212 is YES, and the process in S214 is executed. The value with which the exhaust-side maximum pressure difference α [i] is compared in S500 and S508 is different from that in FIG. 30, but is determined for the same reason. More specifically, the process shown in FIG. 30 is changed depending on whether or not the exhaust-side maximum pressure difference α is 3 or more, whereas the process shown in FIG. The processing is changed depending on whether α [i] is equal to or smaller than −3. In any case, whether or not the assembly failure has occurred is determined by whether or not the absolute value of the exhaust-side maximum pressure difference α [i] is 3 or more (or less), as shown in FIG. This is the same as S106 and the like.

In the flowcharts shown in FIGS. 30 and 31, which of the cam pulley and the driven gear is advanced or delayed by one tooth is determined based on the value of the exhaust-side pressure maximum value reaching angle difference Γ. However, the determination may be performed based on the intake-side pressure maximum value arrival angle difference Λ or the intake-side pressure increase start angle difference Ψ. In addition, a more reliable inspection can be performed by using a plurality of them. In addition, it can be performed based on the exhaust-side pressure-unchanged state transition angle difference Σ, in which case, S402, S410, S502 and S51.
The threshold value used for each determination of 0 is, for example,
It is necessary to change to -12, -12, 8 and 8 and to reverse the inequality sign (that is, “≦” to “≧”,
Change “≧” to “≦”). When there is no possibility of occurrence of a defective assembly of the driven gear, the processes related to the driven gear can be omitted in the above-described flowcharts. Further, in that case, the inspection of the cam pulley may be performed based only on the value of the exhaust-side pressure decrease start angle difference Φ. For example, instead of the processing shown in the flowchart of FIG. 30, when the exhaust-side pressure decrease start angle differences Φ of the cylinders included in each bank are all less than −8, the cam pulley of that bank is advanced by one tooth. A value indicating the presence is set in the defective portion flag flag _cam , and if it is -8 or more, the process for directly terminating the process is executed. In place of the process of FIG. 31, the exhaust pressure of the cylinder included in each bank is When the decrease start angle differences Φ are all greater than 8, a value indicating that the _cam pulley of the bank is one tooth behind is set in the defective portion flag flag _cam , and when all are less than 8, the process ends directly. Processing can be performed.

FIG. 32 is a flowchart showing the contents of the inspection of the valve clearance failure and the compression ring missing in S214 of FIG. First, S60
At 0, 0x01 is set to the variable buf, and S6
At 02, the variable i is initialized to zero, corresponding to piston # 1. Note that the variable i is a variable in which a value obtained by adding 1 to the value indicates the piston number. Subsequently, in S604,
It is determined whether the exhaust-side pressure maximum value difference α [i] is 3 or more. If the result is YES, in S606, it is determined whether the exhaust-side pressure maximum value arrival angle difference Γ [i] is 2 or more. Is determined. When the exhaust-side maximum pressure difference α [i] is 3 or more, it is the same as the above-described processing to determine that there is some assembly failure. Also, it is determined whether or not the exhaust-side maximum pressure angle difference Γ [i] is 2 or more. In this case, as is apparent from FIG. 24, when the exhaust-side maximum pressure difference α is 3 or more. Has an exhaust-side maximum pressure angle difference ５ of 5.
It becomes 4 (large intake valve clearance) or 0 (large exhaust valve clearance). Therefore, the state between the large intake valve clearance and the large exhaust valve clearance is distinguished by comparing the substantially intermediate value 2 with the exhaust-side maximum pressure angle difference Γ [i]. The result is YE
If S, the logical sum of the defective part flag flag _inl and the value of the variable buf is renewed in S608.
Set as the value of ag _inl . The variable buf is adjusted by a process described later so that the bit corresponding to the cylinder indicated by the corresponding piston number of each defective portion flag can be set to 1 by ORing with the variable buf. Therefore, it is possible to specify the cylinder in which the assembly failure has occurred. If the decision result in S606 is NO,
In S610, the logical sum of the defective portion flag flag _exl and the variable buf is set again in the defective portion flag flag _exl .

Following the processing of S608 or S610,
In S612, the variable i is incremented, and in S6
At 14, it is determined whether or not the value of the variable i is 6. If the result is YES, the valve clearance and compression ring missing inspection is completed, and if NO, S6
In step S612, the variable buf is shifted left by one bit.
And the value of the variable buf is incremented by 1.
After the bit number (any of zero to 5) is matched, the processing from S604 is repeated. S6
By performing the OR operation with the contents of the variable buf as described above, the corresponding bit of each defective portion flag is set to 1 by the processing of step 16 and, if an assembly failure occurs, the cylinder is identified. You can do it.

If the result of the determination in S604 is NO, in S618, the exhaust-side pressure maximum value difference α [i] becomes −
It is determined whether the number is 3 or less. If NO, S61
If the second and subsequent processes are executed and YES (the value of the exhaust-side maximum pressure difference α is different from the case where the determination result of S604 is true, but the result is YES if there is some assembly failure), In S620, it is determined whether or not the exhaust-side pressure invariable value difference β [i] is equal to or greater than -5. The reason why the exhaust-side constant pressure difference β [i] is compared with −5 is that, when the exhaust-side maximum pressure difference α is −3 or less, the exhaust-side constant pressure difference β is calculated as shown in FIG. The value you get is
It is either -16 (small intake valve clearance), -10 (small exhaust valve clearance) or -1 (missing compression ring). Here, in order to determine whether or not the compression ring is missing,-
This is because a value approximately halfway between 1 and -10 is set as the threshold value. If the result is YES, the logical sum of the value of the defective portion flag flag _ring and the variable buf is set in the defective portion flag flag _ring in S622, and then the processing of S612 and thereafter is executed. If S620 the determination result is NO, the value of the exhaust pressure maximal value difference α [i] in S624 it is determined whether -30 or less, if YES, the the defective portion flags flag _ins in S626 Variable bu
If the logical sum of the value with f is the defect location flag flag _ins , and if NO, the failure location flag flag is set in S628.
The logical sum of the value of _exs and the value of the variable buf indicates the defective portion flag fl
_After being set to ag _exs , the processing of S612 and thereafter is executed. The reason why the exhaust-side maximum pressure difference α [i] is compared with −30 is that the value that the exhaust-side maximum pressure difference α can take when the determination result of S620 is NO, as is clear from FIG. This is because the threshold value is −47 (small intake valve clearance) or −8 (small exhaust valve clearance), and a substantially intermediate value between them is set as the threshold value. In addition, especially when there is no possibility that the compression ring is missing, the inspection may be performed based on the exhaust-side pressure invariable value difference β instead of the exhaust-side pressure maximum value difference α in S624. In this case, however, the threshold value of S624 needs to be changed from -30 to, for example, -13, which is an intermediate value between -16 and -10.

If it is only necessary to determine whether or not the valve clearance of the intake valve is normal, for example, 排 気> 2 (5.
If the value is approximately halfway between 4 and 0), the valve clearance of the intake valve is large, and if Γ <-3 (the value is approximately halfway between -6.4 and 0), the valve clearance is small. Can be determined. In this case, the exhaust-side pressure maximum value arrival angle difference Γ may be replaced with the intake-side pressure maximum value arrival angle difference Λ or the intake-side pressure increase start angle difference Ψ. When the change in the valve clearance is continuous, the values of the exhaust-side pressure maximum value difference α and the exhaust-side pressure maximum value arrival angle difference Γ also become continuous, but the valve clearance changes gradually. In such a case, the change amounts of the exhaust-side pressure maximum value difference α and the exhaust-side pressure maximum value arrival angle difference Γ are also stepwise. Therefore, it is desirable to change the criterion for abnormality determination according to which engine to be inspected belongs to.

Next, an embodiment (different from the above-described embodiment) common to the first to fifth inventions of the present application will be described. This embodiment is different from S1 shown in FIG.
This is performed as a modification of the content of the defective portion estimation processing of No. 18. The configuration of the engine inspection device shown in FIG. 4 is used as it is in the present embodiment. Whereas the defect location estimation processing of the above-described embodiment is based on the assumption that there is only one assembly failure location, the failure location estimation processing of the present embodiment requires a plurality of types of assembly failure. This is a mode in which at least two of the plurality of types of assembly defects can be detected when they occur simultaneously.
FIG. 33 is a flowchart showing an example of the contents. In FIG. 33, first, in S700, the same processing as in S200 shown in FIG. 27 is performed, and then in S702, inspection 1 as a subroutine is executed. In S704 and S706, inspection 2 and inspection 3 as subroutines, respectively. Is executed, and in S708, FIG.
The defective point display processing similar to that in S120 shown in FIG. 5 is executed, and the defective point estimation processing ends. Hereinafter, the contents of each subroutine of inspection 1, inspection 2 and inspection 3 will be described.

FIG. 34 is a flowchart showing the contents of inspection 1. First, in S800, an initial value of zero (corresponding to piston # 1) is set in a variable i, and in S802
It is determined whether the value of the exhaust-side pressure decrease start angle difference Φ [i] for at least one cylinder included in each of the left and right banks belongs to any of the following ranges (1) to (11). Processing based on the result is performed. Range (1): −42 ≦ Φ [i] <− 32 Range (2): −32 ≦ Φ [i] <− 28 Range (3): −27 ≦ Φ [i] <− 17 Range (4): −17 ≦ Φ [i] <− 13 Range (5): −12 ≦ Φ [i] <− 2 Range (6): −2 ≦ Φ [i] <2 Range (7): 3 ≦ Φ [i] <13 range (8): 13 ≦ Φ [i] <17 range (9): 18 ≦ Φ [i] <28 range (10): 28 ≦ Φ [i] <32 range (11): range (1) To range other than range (10)

In the above range, it is noted that the change in the exhaust-side pressure decrease start angle difference Φ in FIG. 24 occurs only when the assembly failure of the crank pulley and the cam pulley and the exhaust valve clearance small state occur. It is classified as. Crank pulley advanced by 1 tooth, normal, 1
According to the tooth lag, the exhaust-side pressure decrease start angle difference Φ is 15,0,
−15 discretely. In addition, depending on whether the cam pulley is advanced by one tooth, normal, or delayed by one tooth, the angle difference Φ at which the pressure on the exhaust side starts to decrease is Φ.
Changes discretely to -15, 0, and 15. Also, even when the exhaust valve clearance is normal, the exhaust-side pressure decrease start angle difference Φ may vary within a range of −2 or more and less than 2 (in other words, depending on whether or not it is within the range of ± 2). It is determined whether or not the exhaust valve clearance is normal).
It will not be smaller than. In consideration of the above, the entire region of the exhaust-side pressure decrease start angle difference Φ is -30− (10 + 2), −30 ± 2, −15− as shown in FIG.
(10 + 2), -15 ± 2, 0- (10 + 2), 0 ±
2,15- (10 + 2), 15 ± 2,30- (10+
2) It is divided into a plurality of ranges with each value of 30 ± 2 as a boundary value. The above ranges (1) to (11) correspond to the following states of the assembled state of the cam pulley including the crank pulley and the cylinder of interest and the state of the exhaust valve clearance, respectively. Range (1): Crank pulley 1 tooth delayed, cam pulley 1 tooth advanced, and exhaust valve clearance small Range (2): Crank pulley 1 tooth delayed, cam pulley 1 tooth advanced, and exhaust valve clearance normal range ( 3): (Crank pulley 1 tooth delayed, cam pulley is normal and exhaust valve clearance is small), or
(Crank pulley is normal, cam pulley advances by one tooth, and exhaust valve clearance is small) Range (4): (Crank pulley is delayed by one tooth, cam pulley is normal, and exhaust valve clearance is normal) or (crank pulley is normal) , And one cam pulley advance and exhaust valve clearance is normal. Range (5): (normal crank pulley and normal cam pulley and small exhaust valve clearance) or (lead crank crank and advance cam pulley, And (exhaust valve clearance small) or (crank pulley delay and cam pulley delay and exhaust valve clearance small) or range (6): (crank pulley normal and cam pulley normal and exhaust valve clearance) Normal), or
(Crank pulley advance, and cam pulley advance, and
Exhaust valve clearance is normal) or (Crank pulley delay and cam pulley delay and exhaust valve clearance is normal) Range (7): (Crank pulley advances one tooth, cam pulley is normal and exhaust valve clearance is small), Or
(Crank pulley is normal and cam pulley is one tooth delayed and exhaust valve clearance is small) Range (8): (Crank pulley is advanced by one tooth and cam pulley is normal and exhaust valve clearance is normal) or (crank pulley is normal) Range (9): Advance of crank pulley by one tooth, and delay of cam pulley by one tooth, and small exhaust valve clearance. Range (10): Advance of crank pulley by one tooth. Also, one tooth behind the cam pulley and the exhaust valve clearance is normal Range (11): Error

These ranges correspond to the exhaust-side decompression start angle difference Φ due to the assembled state of the crank pulley and one cam pulley.
And the effect on the exhaust-side decompression start angle difference Φ due to the assembly state of the exhaust valve clearance. It can be seen from FIG. 40 that whether the exhaust valve clearance is normal or small has an effect on the exhaust-side depressurization start angle difference Φ independent of the influence of the crank pulley and the cam pulley. The assembling state that the crank pulley can take is three states: normal, advanced, and lag. The same applies to the assembling state of the cam pulley. Therefore, there are nine possible combinations. Or smaller), there can be only 18 states as a combination. However, among the different combinations of the states of the crank pulley and the cam pulley, the exhaust-side decompression start angle difference Φ
Because the same effect on the above, the above 10 (range (11)
Is excluded). That is, an inspection using only the exhaust-side depressurization start angle difference Φ may not identify the assembled state of the crank pulley and the cam pulley. Specifically, the above ranges (3), (4), (7) and
In (8), it is not possible to specify which of the two assembled states (crank pulley and cam pulley). Further, in ranges (5) and (6), it is not possible to specify which of the three assembled states respectively.

However, the inspected engine 90 of the present embodiment
As described above, in the case of an engine having two banks on the left and right, the assembly state of the left and right banks can be acquired independently of the combination of the assembly states described above. If these two pieces of information are used, the states that can be specified when there are no two banks are four states (a range
(1), (2), (9) and (10)), 24 states out of 54 states can be specified as described below. For each combination of the states of the crank pulley and the cam pulleys of the left and right banks (3 ³ = 27 sets exist), the influence on the exhaust-side decompression start angle difference Φ of the cylinders included in the left and right banks is obtained. That is, there are twelve sets out of the two sets of values of the exhaust-side decompression start angle difference Φ that are different from the values of the other sets. That is, out of the 27 states, 12 states can be specified. Although the above description considers only the assembled state of the crank pulley and the cam pulley, the assembled state of the exhaust valve clearance which can be specified independently of these assembled states (two states of normal or small). Taking into account the effect on the exhaust-side decompression start angle difference Φ due to the above, 24 states (twice the 12 states) out of 54 states (twice the 27 states) can be specified.

Specifically, considering only the set of the assembled state of the crank pulley and the cam pulleys of the left and right banks, the influence on the exhaust-side depressurization start angle difference Φ is as follows. When the cam pulley is one tooth late, it is 0, 15, and -15, respectively, and when the assembled state of each cam pulley is one tooth advanced and one tooth delayed, it is 0, -15, and 15 respectively. A set of values of both banks obtained by adding the values of the former and the latter is (0, 0), (0, −1).
5), (0, -30), etc. (0 or ± 15 or ± 3
Of the 25 sets (0, 0 or ± 15 or ± 30), 20 sets in which the magnitude of the difference between the values corresponding to the respective banks is 30 or less can be actually generated. Corresponds to a pair. That is, the above 2
Each of the 7 states has 20 sets of exhaust side decompression start angle differences Φ
Corresponding to any of the sets of values. In each of the elements of these sets, the first element is the exhaust-side decompression start angle difference Φ between the left bank and the second element is the right bank. Then, of these 20 sets, the values that are different from the values of the other sets and can specify the corresponding assembly state are (0, -30),
(0, 30), (-15, -30), (-15, 1
5), (−30, 0), (−30, −15), (−3)
0, -30), (15, -15), (15, 30),
(30, 0), (30, 15), 12 of (30, 30)
It is a pair. For example, (0, -30) occurs only when the crank pulley is one tooth delayed, the left bank is one cam pulley delayed, and the right bank is one cam pulley advanced.

However, (0, -15), (0, 15),
(-15, 0), (-15, -15), (15, 0),
The six sets (15, 15) respectively correspond to two assembled states. For example, (0, -15) indicates that the crank pulley is normal, the left bank is normal cam pulley, and the right bank is one cam pulley advanced, or that the crank pulley is one tooth delayed and the left bank is one cam pulley tooth. Occurs either late or when the right bank is normal. Further, (0, 0) corresponds to three assembled states (described later). As described above, 12 states can be specified from the 27 states. However, it can be concluded that the fifteen states that cannot be clearly identified are any one of at least two or three assembled states. Such information is sufficiently useful in actual engine inspection and subsequent correction of defective parts. The influence of the assembly state of the exhaust valve clearance can be specified independently of the advance / delay of one tooth of the crank pulley, so that 24 states out of 54 states can be specified in the end.

In an actual engine test, (0,0) appears most frequently among the above set of values. This is because it is a set of values corresponding to that the crank pulley and the cam pulley are in a normal assembly state. However, (0,
0) is further advanced by one tooth of the crank pulley, and both left and right banks are advanced by one tooth of the cam pulley (ie,
(15 + (− 15), 15 + (− 15)) = (0, 0)
), The crank pulley is one tooth delayed, and both the left and right banks are delayed by one cam pulley tooth ((−15 + 1)
5, -15 + 15) = (0,0)). That is, in the inspection based on only the exhaust-side decompression start angle difference Φ, it may seem that it may not be possible to distinguish between a normal assembly state and an assembly failure state. However, when concretely considered, the crank pulley is advanced by one tooth and the left and right banks are advanced by one cam pulley, the crank pulley is advanced by one tooth, and the left and right banks are advanced by one cam pulley. The state is the same even if only the timing belt is displaced by one tooth in an engine in which the crank pulley and the cam pulley are normally assembled, and does not adversely affect the operation of the engine.

It is considered that the determination as to whether or not all the assembly states in which (0,0) can be obtained is the normal assembly state depends on the inspection system when the engine is partially disassembled and assembled. For example, advance the crank pulley one tooth,
If only one of the left and right banks is replaced with one of the cam pulleys of the engine in which the left and right banks are advanced by one cam pulley, only the replaced cam pulley is in a normal assembled state, and the engine as a whole is , Which may result in an assembly failure. Therefore, it is considered that all the assembly states where (0, 0) can be obtained are not good as normal assembly states. However, when the engine is partially disassembled and assembled, the engine inspection of the present invention is performed again.
Alternatively, such an assembly failure can be prevented beforehand by performing at least an operation in which inspection is performed on a place where disassembly / assembly is performed and a place closely related to the place. . Therefore, in the present embodiment, when (0, 0) is obtained, it is assumed that the assembled state of the crank pulley and the cam pulley is normal.

In S802, the exhaust-side pressure decrease starts.
When the range to which the value of the angle difference Φ [i] belongs is the range (6),
Is the assembled state of the crank pulley and cam pulley,
Lube clearance is normal and other judgments are made
The process of S802 ends without any processing. On the other hand,
In the case of box (1), the defective portion flag flag_crnkNiku
0x02 indicating that the rank pulley is one tooth behind is incorrect.
Good point flag flag _camThe cam pulley is one tooth ahead
Value (in the case of the left bank, the current value and 0x
01 and the current value if the right-hand bank is the logical sum
(The logical sum with 0x04 is set.)
Location flag flag_exsThe bit corresponding to the variable i is 1
It is said. If the range is (2), the line is
The bad part flag flag_exsOmit changes about
Is done. Hereinafter, similarly, it is any of the ranges (3) to (10)
The value of the bit of the corresponding defect point flag
Set. In the case of belonging to the range (11), FIG.
Defective location flag flag_crnk, Flag_camYou
And flag_exsBit is set to 1 and an error occurs
It indicates that there is a possibility. This most significant bit
Of the engine inspection device itself based on the fact that
Process to prompt inspection workers for
You. In the present embodiment, if it belongs to the range (11),
Stop the subsequent processing and perform the engine assembly status inspection.
The above shall not be performed. When the above processing is completed, S
At 804, the variable i is incremented, and at S80
At 6, it is determined whether the value of the variable i is 6. Results
If YES, the test 1 ends, and if NO, S8
The process from 02 is repeated. Inspection 1 explained above
In the processing of, regardless of the presence or absence of other defective parts,
Is at least the valve clearance of the exhaust valve small?
Can be clearly checked, and the crank pulley and
In some cases, the assembled state of the cam pulley can be specified. Less
However, these assembly conditions have a negative effect on the operation of the engine.
It is possible to clearly check whether the condition has no effect.
You.

FIG. 35 is a flowchart showing the processing contents of inspection 2 which is a subroutine called in S704 shown in FIG. First, in S900,
A value based on the result of the test 1 shown in FIG. 34 is set in the variable Δ _odd and the variable Δ _even . In particular,
The value of the exhaust-side depressurization start angle difference Φ of the cylinders included in the left bank is in the range (1) related to the above-described exhaust-side depressurization start angle difference Φ.
Or, if it is included in (2), -30 is _added to Δ _odd ,
When included in (3) or (4), −15 is _added to Δ _odd ,
If it is included in the range (5) or (6), 0 is set to Δ _odd ,
When included in the scope (7) or (8), 15 the delta _odd
Is included in the range (9) or (10), Δ
30 is set to _odd respectively. For the right bank, a similar process is performed on the variable _Δeven . After the variable i is initialized to zero in subsequent S902, S904
In the variable Δ _odd and the variable Δ _even , the variable i
After the value of the bank to which the cylinder indicated by 属 す る belongs is set to the variable Δ, the exhaust-side pressure maximum value arrival angle difference Γ [i] belongs to any of the ranges (1) to (12) shown below. Is determined. Range (1): −30 ≦ Γ [i] −Δ <−20 Range (2): −20 ≦ Δ [i] −Δ <−16 Range (3): −16 ≦ Δ [i] −Δ <− 12 Range (4): −12 ≦ Γ [i] −Δ <−6 Range (5): −6 ≦ Γ [i] −Δ <−2 Range (6): −2 ≦ Γ [i] −Δ < 2 Range (7): 2 ≦ Γ [i] −Δ <6 Range (8): 6 ≦ Γ [i] −Δ <12 Range (9): 12 ≦ Γ [i] −Δ <16 Range (10) : 16 ≦ Γ [i] −Δ <20 Range (11): 20 ≦ Γ [i] −Δ <30 Range (12): Range other than range (1) to range (11)

The above range has an influence on the exhaust-side pressure maximum value reaching angle difference Γ in FIG. 24, in addition to the assembly failure of the crank pulley and the cam pulley, the assembly failure of the driven gear and the large / small intake valve clearance. Paying attention to only the state, the entire region of the value obtained by subtracting the variable Δ from the exhaust-side pressure maximum value arrival angle difference Γ is divided. The value of the exhaust-side pressure maximum value reaching angle difference Γ is a value obtained by adding the effects of the assembly failure of the crank pulley and the cam pulley, the assembly failure of the driven gear, and the effect of the large / small intake valve clearance. The value obtained by subtracting the variable Δ representing the effect of the defective assembly of the crank pulley and the cam pulley from the maximum value arrival angle difference Γ is a value that is not affected by the defective assembly of the crank pulley and the cam pulley. Therefore, the range of values (範 囲 −Δ) that are not affected by the assembly failure of the crank pulley and the cam pulley is considered depending on the occurrence of the failure of the driven gear assembly and the large / small intake valve clearance. Then, the above range is obtained. Exhaust side pressure decrease start angle difference Φ is -18,0,18 according to one tooth advance, normal, one tooth delay of driven gear.
And changes discretely. Also, even when the intake valve clearance is normal, the exhaust-side pressure maximum value arrival angle difference Γ is −
There is a possibility that it will vary in the range of 2 or more and less than 2, and even in the large / small state of the intake valve clearance, the exhaust-side pressure maximum value arrival angle difference 変 化 does not change more than ± 10 from the normal case. In consideration of the above, the region of the value obtained by subtracting the variable Δ from the exhaust-side pressure maximum value arrival angle difference Γ is −18 ± (10 + 2), −18 ± 2, 0 ±, as shown in FIG.
(10 + 2), 0 ± 2, 18 ± (10 + 2), 18 ± 2
It is divided into a plurality of ranges with the values of etc. as boundary values.

The ranges (1) to (12) indicate that the driven gear and the valve clearance of the intake valve are in the following states, respectively. Range (1): Driven gear one tooth and small intake valve clearance Range (2): Driven gear one tooth and normal intake valve clearance Range (3): Driven gear one tooth and large intake valve clearance ( 4): Indefinite range (5): Normal driven gear and small intake valve clearance range (6): Both are assembled normally Range (7): Normal driven gear and large intake valve clearance range (8): Undefined range (9 ): Driven gear one tooth delayed and intake valve clearance small range (10): Driven gear one tooth advanced and intake valve clearance normal range (11): Driven gear one tooth delayed and intake valve clearance large range (12): error

When the value of the exhaust-side pressure maximum value arrival angle difference Γ [i] belongs to the range (6), S912 is executed without performing any processing. Exhaust pressure maximum value arrival angle difference Γ
When the value of [i] is in the range (1) to (3), the range (5), (7), and the range
If it belongs to any of (9) to (12), the process of S906 is performed. For example, if it belongs to the range (1), a value indicating a state in which the driven gear related to the corresponding cylinder is advanced by one tooth and the intake valve clearance is small is set in the defective portion flags flag _drvn and flag _ins .
Specifically, when the variable i is 0, the logical sum of the current value of the defective portion flag flag _drvn and 0x04 is set in the defective portion flag flag _drvn , and the defective portion flag f
logical sum of the current value and 0x01 of lag _ins is set to the defective portion flag flag _ins. Hereinafter, similarly, a value is set to a bit corresponding to the corresponding defective portion flag. In the case of belonging to the range (12), in the present embodiment, the exhaust-side decompression start angle difference Φ is in the range (11) (FIG. 40).
Similarly, the subsequent processing is stopped.

If the value of the exhaust-side pressure maximum value arrival angle difference Γ [i] belongs to the range (4), the subroutine test 2-1 (described later) is executed in S908, and if it belongs to the range (8). In step S910, inspection 2-2 (described later), which is a subroutine, is executed. When the processing of S906, S908 or S910 is completed, after the variable i is incremented in S912, it is determined in S914 whether or not the value of the variable i is 6. If the result is YES, a test 2 which is a subroutine described later in S916
Inspection 2 ends after -3 is executed, and if NO,
The processing from S904 is repeated. In the process of the inspection 2 described above, the assembly state of the driven gear and whether or not the valve clearance of the intake valve is normal regardless of the presence or absence of other defective portions are unknown (12). ) Can be determined independently, except in the case of). However, when the value of the exhaust-side pressure maximum value arrival angle difference Γ [i] belongs to the range (8), it cannot always be determined independently as described later.

FIG. 36 is a flowchart showing the contents of test 2-1 which is a subroutine called in S908 of FIG. This processing is performed if the value of the exhaust-side pressure maximum value arrival angle difference Γ [i] belongs to the range (4) because the cause is that the driven gear advances one tooth and the intake valve clearance is large. Since it is not possible to determine whether the intake valve clearance is small based on only the exhaust-side pressure maximum value arrival angle difference Γ [i], these determinations are performed using other values. In the example of FIG. 36, this is determined from the sum of the exhaust-side pressure decrease start angle difference Φ [i] and the exhaust-side pressure unchanged state transition angle difference Σ [i] as a variable Δ (see the description of S904 above). Is performed based on the absolute value of a value obtained by subtracting a value obtained by multiplying by 2 (hereinafter, simply referred to as a comparison value). This is because the exhaust-side pressure decrease start angle difference Φ [i] shown in FIG.
As is clear from the values of the transition angle difference [i] and the like, the above value is 8.4 when the driven gear is advanced by one tooth and the intake valve clearance is large.
(= | -8.4 + 0 |), whereas when the intake valve clearance is small, it becomes zero (= | 0 + 0 |) For example, when the cam pulley advances one tooth, Φ The value of [i] + Σ [i] is -30 (= -15-1)
5), and increases by 30 = (15 + 15) when a cam pulley 1 tooth delay occurs. Further, when one tooth advance of the crank pulley and one tooth delay of the cam pulley occur, the value of Φ [i] + Σ [i] is 60 (= 30 + 30).
As described above, twice the variable Δ is subtracted from the sum of the exhaust-side pressure decrease start angle difference Φ [i] and the exhaust-side pressure unchanged state transition angle difference Σ [i] as described above. As a result, the influence of the advance / delay of one tooth of the crank pulley and the cam pulley is removed, and therefore, they are not affected by them.

In S1000, | Φ [i] + Σ
It is determined whether or not [i] −2 · Δ | is less than 4, which is a value approximately halfway between zero and 8.4. If the result is YES, it is determined that the intake valve clearance is small, and S1002
Is NO, it is determined that the driven gear advances by one tooth and the intake valve clearance is large, the process of S1004 is executed, and the inspection 2-1 ends. S1002 is
This is a process of setting 1 to a corresponding bit of the defective portion flag flag _ins.
This is a process of setting 1 to the corresponding bit of flag _drvn and flag _inl .

FIG. 37 is a flowchart showing the contents of test 2-2 which is a subroutine called in S910 of FIG. This processing is performed if the value of the exhaust-side pressure maximum value arrival angle difference Γ [i] belongs to the range (8), because the cause is that the driven gear is one tooth delay and the intake valve clearance is small. Since the determination as to whether the intake valve clearance is large cannot be made based only on the exhaust-side pressure maximum value arrival angle difference Γ [i], these determinations are performed using other information. This is a process performed as a pre-process. More specifically, in S1100 and S1102, each of the defective portion flags
The corresponding bit of _inl and flag _ins is set to 1. It is impossible that both of the bits corresponding to the same cylinder in these defective portion flags are set to 1, which means that the value of the exhaust-side pressure maximum value arrival angle difference Γ [i] falls within the range.
It shows that it belongs to (8). This is shown in FIG.
Are used in the processing described later.

FIG. 38 is a flowchart showing the contents of test 2-3 which is a subroutine called in S916 of FIG. In this process, when there is a cylinder whose exhaust-side pressure maximum value arrival angle difference Γ [i] belongs to the range (8), the assembling state of the cylinder is reduced in intake valve clearance and delayed by one tooth of the driven gear. Is it in the state of
In this process, it is determined whether the intake valve clearance is large based on the inspection result of another cylinder in the bank including the cylinder. First, after the variable i is set to zero in S1200, it is determined in S1202 whether both the bit corresponding to the cylinder indicated by the variable i of the defective portion flag flag _inl and the flag _ins are 1 or not. If the result is YES, the value of the exhaust-side pressure maximum value arrival angle difference Γ [i] of the cylinder belongs to the range (8). In this case, in S1204, it is determined whether or not the bank including the cylinder indicated by the variable i is one tooth behind the driven gear. If the result is YES, if the value of the exhaust-side pressure maximum value arrival angle difference Γ [i] belongs to the range (8), the driven gear cannot be delayed by one tooth and the intake valve clearance cannot be large. The cylinder indicated by the variable i is
It is determined that the valve clearance of the intake valve is in a small state, and the bit corresponding to that cylinder of the defective portion flag flag _inl , which was temporarily set to 1 in S1100 of FIG. 37, is set to zero in S1206. It is substantially determined that the valve clearance is small), and then the process of S1208 is performed. On the other hand, if the decision result in the step S1204 is NO, the process directly goes to the step S12.
08 is executed. After the variable i is incremented in S1208, it is determined whether or not the variable i is 6 in S1210. If YES, the inspection 2-3 ends, and if NO, the processing from S1202 is repeated. It should be noted that in the state where this process is completed, there are cases where the assembled state of the cylinders in which the value of the exhaust-side pressure maximum value arrival angle difference Γ [i] belongs to the range (8) is indeterminate. That is, S1204
Is determined to be NO. If such a cylinder exists, the defective portion flags flag _inl and fl
Both bits corresponding to that cylinder in ag _ins are kept at 1, and this can be used to notify the inspection operator of the situation.

FIG. 39 is a flowchart showing the contents of test 3, which is a subroutine called in S706 shown in FIG. In this process, when all the results of the inspections performed in the inspections 1 and 2 indicate a normal assembly state, it is possible to find a cylinder in which the valve clearance of the exhaust valve is not large. However,
As a result of the inspections 1 and 2, if at least one of the driven gear and the intake valve clearance is found to be defective in assembly, the exhaust gas related to the cylinder whose exhaust-side constant pressure difference β is affected by the defective assembly. The state of the valve clearance of the valve is said to be unknown. If it is determined that the exhaust valve clearance is in the small state at the time when the inspection 2 is completed, the exhaust valve clearance cannot be set to the large state for the cylinder. Therefore, the processing shown in FIG. 39 (the processing in S1312 described later) ) Performs substantially no processing for that cylinder.
For a cylinder that is not affected by a change in the value of the exhaust-side constant pressure difference β due to at least one assembly failure of the driven gear and the intake valve clearance, the value of the exhaust-side pressure invariable value difference β [i] may be affected. Possible assembly defects are
Only the compression ring is missing and the exhaust valve clearance is large. Among them, the effect of the compression ring missing is small (see FIG. 24). Therefore, when the value of the exhaust-side pressure invariable value difference β is 7 or more, it can be determined that the cylinder is in the state of the large exhaust valve clearance, otherwise, it is determined that the cylinder is not at least in the state of the large exhaust valve clearance. Note that the value (7) to be compared with the exhaust-side constant pressure difference β [i] in S1304 is merely an example, like the other threshold values described above.

After the variable i is cleared to zero in S1300, in S1302, the driven gear of the bank corresponding to the cylinder indicated by the variable i and the intake valve clearance of the cylinder are in a normal assembly state, and the exhaust valve clearance of the cylinder is Is determined to be not small. If the result is YES, S13
In 04, the value of the exhaust-side pressure invariable value difference β [i] is 7
It is determined whether or not the above is true, and if the result is YES,
After it is determined that the exhaust valve clearance of the cylinder is large and the corresponding bit of the defective portion flag flag _exl is set to 1 in S1306, the process of S1308 is executed. If the determination result in S1304 is NO, the direct S
Step 1308 is executed. In this case, it is known that the exhaust valve clearance of the cylinder is in a normal assembly state, and the significance of performing the inspection 3 is here. S1308
In step S13, after the variable i is incremented,
At 10 it is determined whether the value of the variable i is 6 and YES
If it is, the inspection 3 ends, and if NO, the processing from S1302 is repeated. If the determination result in S1302 is NO
If it is determined that the assembly state of the exhaust valve clearance of the cylinder indicated by the variable i is unknown, the corresponding bit of the defective portion flag flag _exl is set to 1 in S1312 and the most significant bit is set to 1 in S1312. S13
08 is executed. That is, the defective portion flag fl
_If the most significant bit of the defective portion flag flag _exl is 1, the cylinder corresponding to the bit set to 1 in ag _exl is unclear whether the exhaust valve clearance is large or not. However, as described above, since the cylinder to be inspected has a small exhaust valve clearance, S1302
Is NO, the process of S1312 is not executed.

In the present embodiment, the compression ring missing inspection is performed for each cylinder based on the value of the exhaust-side maximum pressure difference α when there is no other assembly failure. Although illustration of the processing content is omitted, specifically, a crank pulley,
No assembly failure of the cam pulley and the driven gear has occurred, and the absolute value of the exhaust-side constant pressure difference β is, for example, 3
Is less than, for example,-
If the number is equal to or less than 5, it is determined that the cylinder is in the compression ring missing state, and the defective portion flag
1 is set to the corresponding bit of the _ring . However, the bit corresponding to the cylinder in which the value of the exhaust-side maximum pressure difference α changes due to the presence of another assembly defect remains 0. Then, if such a cylinder is present, 1 is set to the most significant bit of the defective portion flags flag _{ri ng.} That is, if the most significant bit of the defective portion flag flag _ring is 1, cylinder corresponding to the bits being one defective portions flag flag _ring is a compression ring missing condition, corresponding to the bits being 0 It is unknown whether the compression cylinder is in a compression ring missing state or not. The value of the exhaust-side maximum pressure difference α is −5.
As is clear from FIG. 24, in the state where the compression ring is missing, since the exhaust-side maximum pressure difference α shows a value of about −10, an intermediate value between 0 and −10 is a threshold. It was adopted as a value. The absolute value of the exhaust side constant pressure difference β is compared with 3 because the absolute value of the exhaust side constant pressure difference β is obtained when the above-described assembly failure does not occur and the intake and exhaust valve clearances are both normal. This is because the value is less than 3 (see FIG. 24).

As described above, in the engine inspection apparatus of the present embodiment described above, when the inspection result is rejected, at least two of a plurality of possible assembly defects can be detected. However, this cannot always be achieved. For example, if the compression ring is missing for a certain cylinder and the cam pulley is advanced by one tooth in the bank including the cylinder, it is not determined whether or not the compression ring is missing for that cylinder. . However, for example, information such as the exhaust-side pressure maximum value difference α when the assembly failure such as a cam pulley 1 tooth advance / delay and the compression ring missing simultaneously occur is obtained in advance, and the inspection is performed based on the information. By doing so, more detailed information about their assembled state may be obtained. Thus, FIG.
The inspection may be performed using information other than the information shown in (1).

FIG. 42 is a block diagram of an embodiment common to the engine inspection apparatuses of the first, second, fourth, and fifth inventions of the present application. In the present embodiment, each bank has 3
An exhaust manifold 250 which communicates with the exhaust ports 100 of the two cylinders and collects them into one exhaust pipe.
Are attached to the left and right banks, respectively, and a pressure sensor 1 is provided on the exhaust gas outlet side of the exhaust manifold 250.
The masking member 102 provided with a reference numeral 06 is attached. That is, the intake side space is the same as the configuration of the above-described embodiment shown in FIG.
0 and the space inside the exhaust manifold 250. In the configuration of this embodiment, one masking member 102 on the exhaust side, one pressure sensor 106, and the like are provided for each bank, and the configuration is simplified as compared with the above-described embodiment.

FIG. 43 shows the engine inspection device shown in FIG.
Exhaust pressure P obtained by _EXThe crank reference
It is shown together with the signal. This figure shows the normal assembly
Condition, cam pulley 1 tooth advance / lag occurred in left bank
Exhaust pressure P_EXIt is shown. FIG.
Exhaust pressure P shown in 43_EXRepeated and enlarged
Things. FIG. 45 shows the normal assembly state and the left side.
When the driven gear 1 tooth advance / lag occurs in the bank
Exhaust pressure P_EXIt is shown. FIG. 46 shows in FIG.
Exhaust pressure P_EXAre repeated and enlarged.
You. Based on FIGS. 44 and 46, the cam pulley and
Exhaust-side pressure pole in the event of poor gear and driven gear assembly failure
Large value arrival angle difference Γ, exhaust side pressure unchanged state transition angle difference Σ, exhaust
The maximum value of the pressure difference α on the exhaust side and the difference β
The stopped chart is shown in FIG. In FIG. 47,
“Subscript 1” and “subscript 2” are shown in FIG. 44 and FIG.
Exhaust pressure maximum value reaching angle difference Γ shown, Exhaust pressure unchanged
Subscripts such as the state transition angle difference Σ match, and “subscript 1”
Is when the cam pulley or driven gear advances one tooth
The value “subscript 2” indicates that the cam pulley or driven gear
It represents a value in the case of one tooth delay.

When FIG. 47 is compared with FIG. 24, the values of the exhaust-side pressure maximum value reaching angle difference Γ and the exhaust-side pressure unchanged state transition angle difference Σ respectively match the values in FIG.
The values of the exhaust-side pressure maximum value difference α and the exhaust-side pressure invariable value difference β are both smaller than the values in FIG. This is because, in the inspection apparatus of the embodiment shown in FIG. 4 that acquires the values in FIG. 24, the space for which the exhaust pressure _PEX is measured is only the space inside the cylinder and the exhaust port 100. On the other hand, in the inspection apparatus of the present embodiment shown in FIG.
This is because the space is increased by adding the internal space, and the volume increases, so that the magnitude of the pressure change decreases. Despite such an increase in the volume, the values of the exhaust-side pressure maximum value arrival angle difference Γ and the exhaust-side pressure unchanged state transition angle difference Σ respectively match the values shown in FIG. It is shown that if the values are used, the state of advance / delay of one tooth of the driven gear can be detected even by the simplified inspection device shown in FIG. The changes in the waveforms shown in FIGS. 44 and 46 show that the cam pulley and the driven gear are 1
This is a tooth advance / delay state, which occurs because the timing at which the intake valve and the exhaust valve open and close changes as compared to the normal assembly state. Therefore, also in the engine inspection apparatus according to the present embodiment, the valve clearances of the intake valve and the exhaust valve can be inspected by examining the waveform changes as shown in FIGS. 44 and 46 in detail. For example, the values of the exhaust-side pressure maximum value difference α, the exhaust-side pressure invariable value difference β, the exhaust-side pressure maximum value arrival angle difference Γ, and the exhaust-side pressure unchanged state transition angle difference Σ shown in FIG. Since the cause is a defective assembly of the cam pulley and the driven gear, the value changes stepwise. Therefore, when each of these values becomes a value other than that shown in FIG. 47, it can be determined that at least the valve clearance of the intake valve or the exhaust valve may be abnormal.

In each of the embodiments described above, the space inside the intake port 92, the intake manifold 94, and the surge tank 96 is set as the intake side space. For example, only the space inside the intake port 92 is used. Can be used as the intake side space. In this case, since the pressure sensor 98 is also provided for each cylinder, the intake pressure of each cylinder can be obtained independently, and the specific pressure of the intake pressure for each cylinder can be obtained. The assembly state may be inspected based on the change state. Further, in each of the above embodiments, the exhaust-side space is closed, but the intake-side space may be closed in addition to or instead of the exhaust-side space. When the intake-side space is, for example, only the space inside the intake port 92 and is closed, the exhaust-side maximum pressure difference is similar to the exhaust-side pressure in the configuration shown in FIG. pressure difference corresponding to α and constant pressure difference β on the exhaust side,
Since an angle difference corresponding to the exhaust-side depressurization start angle difference Φ or the like can be obtained, the assembly state may be inspected in consideration of these values.

In each of the embodiments described above, the V6DOHC gasoline engine is targeted for inspection. However, the invention of the present application can be applied to inspection of other types of engines. For example, in the SOHC engine, the above-described inspection on the driven gear may be omitted. In a DOHC engine in which the intake-side camshafts 32 and 34 are driven by different cam pulleys, an inspection on another cam pulley can be performed instead of an inspection on a driven gear. Also,
Exhaust pressure P _EX characteristic value a is the exhaust side pressure maximal value P _{EXma x} for changes in the exhaust side pressure maximal value reached angle θ
_Although the engine assembly inspection is performed based on values such as _{EXmax, the} inspection may be performed based on other values shown in FIG. 24 or further characteristic amounts of curves shown in graphs such as FIG. Good. For example, the inspection may be performed by further taking into account the maximum value of the slope of the curve, the crank angle at which the curve occurs, and the length and position of the section where the rate of change of the curve is equal to or greater than a preset change rate. it can. Further, the present invention can be applied not only to a gasoline engine but also to a diesel engine.

When the causes of the above-mentioned assembly failures occur simultaneously, the inspection may be performed using more information in order to more reliably point out the failure points that occur simultaneously. For example, a state in which the above-described assembly failure occurs in all combinations is intentionally generated in advance, and a set of values such as the exhaust-side pressure maximum value P _EXmax in each of the assembly failure states is acquired. Then, a state corresponding to the set of values closest to each other is determined as the assembly state of the engine to be inspected. Further, in each of the above embodiments, the assembly failure of the crank pulley, the cam pulley, and the driven gear is regarded as advance / delay of only one tooth. However, a configuration may be employed in which advance / delay of two or more teeth can be detected. In this case, the exhaust pressure maximum value P used in each of the above-described determinations is determined.
_Processing such as classifying values such as _EXmax in more stages can be performed. In the above case, it is necessary that a delicate difference between the values such as the exhaust-side pressure maximum value P _EXmax is clear, but in the engine inspection device of each embodiment of the present invention, On the other hand, since a large amount of data can be quickly acquired, a more reliable inspection can be performed by performing statistical processing or the like.

As described above, some embodiments of the present invention have been exemplified, but these are literal examples, and the present invention is embodied in various modified and improved forms without departing from the scope of the claims. be able to.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a partially omitted internal configuration of a V6 gasoline engine.

FIG. 2 is a perspective view showing a state in which assembly failure of a crank pulley and a cam pulley has occurred in the V6 gasoline engine of FIG. 1;

FIG. 3 is an enlarged sectional view showing a part of a valve train of a general engine.

FIG. 4 is a system diagram showing a main part of an engine inspection apparatus used for implementing an engine inspection method which is one embodiment common to the first to eighth inventions of the present application.

FIG. 5 is a front view schematically showing the whole of the engine inspection device.

FIG. 6 shows a piston position PP in a normal assembly state and an exhaust pressure P _EX obtained by the engine inspection device.
And the change in the intake side pressure P _IN with the crank angle θ _crank
It is a graph shown by the relationship with.

[7] obtained by the engine testing apparatus, the change of the exhaust pressure P _EX of the crank reference signal and the cylinders in normal assembled condition, is a graph showing the relationship between the crank angle theta _crank.

FIG. 8 is a graph showing a change in the exhaust-side pressure P _EX in a normal assembly state and a small intake valve clearance state obtained by the engine inspection apparatus, in relation to a crank angle θ _crank .

FIG. 9 is a graph showing a change in the exhaust-side pressure P _EX in a normal assembly state and a large intake valve clearance state obtained by the engine inspection apparatus in relation to a crank angle θ _crank .

FIG. 10 is a graph showing changes in the intake-side pressure P _IN in a normal assembly state, a small intake valve clearance state, and a large intake valve clearance state, obtained by the engine inspection apparatus, in relation to a crank angle θ _crank. .

FIG. 11 is a graph showing the relationship between the exhaust side pressure P _EX and the crank angle θ _{crank in} a normal assembly state and a small exhaust valve clearance state obtained by the engine inspection device.

FIG. 12 is a graph showing the relationship between the exhaust side pressure P _EX and the crank angle θ _{crank in} a normal assembly state and a large exhaust valve clearance state, obtained by the engine inspection device.

FIG. 13 is a graph showing a relationship between an exhaust side pressure P _EX and a crank angle θ _{crank in} a normal assembly state and a compression ring missing state, obtained by the engine inspection device.

FIG. 14 is a graph showing a relationship between a crank reference signal and an exhaust-side pressure P _EX of each cylinder and a crank angle θ _crank obtained by the engine inspection device in a state where the cam pulley advances by one tooth.

FIG. 15 is a graph showing a relationship between a crank reference signal and an exhaust-side pressure P _EX of each cylinder and a crank angle θ _crank in a state in which one tooth of a cam pulley is acquired, obtained by the engine inspection device.

FIG. 16 is a graph showing a relationship between a crank reference signal and an intake pressure P _IN and a crank angle θ _{crank in} a normal assembly state, a cam pulley one tooth advance state, and a cam pulley one tooth delay state acquired by the engine inspection device. It is.

FIG. 17 is a graph showing a relationship between the exhaust side pressure P _EX and the crank angle θ _{crank in} a normal assembly state and a cam pulley one-tooth advanced state acquired by the engine inspection device.

FIG. 18 is a graph showing the relationship between the exhaust side pressure P _EX and the crank angle θ _crank in a normal assembly state and a state in which the cam pulley is one tooth delayed.

FIG. 19 is a diagram illustrating a crank reference signal and an exhaust-side pressure P _EX and a crank angle θ _crank in a driven gear 1 tooth advanced state.
6 is a graph showing a relationship with the graph.

FIG. 20 is a diagram illustrating a crank reference signal and an exhaust-side pressure P _EX and a crank angle θ _crank in a driven gear one tooth delay state;
6 is a graph showing a relationship with the graph.

FIG. 21 is a graph showing a relationship between a crank reference signal and an intake pressure P _IN and a crank angle θ _crank in a normal assembly state, a driven gear one tooth advanced state and a driven gear one tooth delayed state.

FIG. 22 is a graph showing the relationship between the exhaust side pressure P _EX and the crank angle θ _crank in a normal assembly state and a driven gear 1 tooth advanced state.

FIG. 23 is a graph showing a relationship between the exhaust-side pressure P _EX and the crank angle θ _crank in a normal assembly state and a driven gear one tooth delay state.

FIG. 24 shows the exhaust-side pressure maximum value difference α, the exhaust-side pressure unchangeable value difference β, the exhaust-side pressure maximum value arrival angle difference Γ, and the exhaust-side pressure unchanged state transition angle when each assembly failure occurs independently. 5 is a table showing an example of a difference Σ, an exhaust-side pressure decrease start angle difference Φ, an intake-side pressure maximum value arrival angle difference Λ, and an intake-side pressure increase start angle difference Ψ.

FIG. 25 is a graph showing R included in a determinator of the engine inspection device;
It is a flowchart showing the main routine of the assembly state inspection stored in OM.

FIG. 26 is a front view showing a configuration of a display of the engine inspection device.

FIG. 27 is a flowchart illustrating a defective portion estimation routine executed in S118 of FIG. 25;

FIG. 28 is a diagram showing a bit configuration of a defective portion flag stored inside a RAM included in the determination unit.

FIG. 29 is a flowchart illustrating a crank pulley inspection routine executed in S202 of FIG. 27.

30 is a flowchart showing a cam pulley and driven gear inspection 1 routine executed in S206 of FIG. 27.

FIG. 31 is a flowchart illustrating a cam pulley and driven gear inspection 2 routine executed in S210 of FIG. 27;

FIG. 32 is a flowchart illustrating a valve clearance and compression ring missing inspection routine executed in S214 of FIG. 27;

FIG. 33 is a flowchart showing another embodiment of the defective portion estimation routine executed in S118 of FIG. 25.

34 is a test 1 performed in S700 of FIG.
It is a flowchart showing a routine.

FIG. 35 shows inspection 2 performed in S702 of FIG.
It is a flowchart showing a routine.

36 is an inspection 2 performed in S908 of FIG. 35.
3 is a flowchart illustrating a -1 routine.

FIG. 37 shows inspection 2 performed in S910 of FIG.
4 is a flowchart illustrating a -2 routine.

38 is a test 2 performed in S916 of FIG. 35.
It is a flowchart showing a -3 routine.

39 is an inspection 3 performed in S704 of FIG.
It is a flowchart showing a routine.

40 is a graph showing the range of the value of the exhaust-side pressure decrease start angle difference Φ used in the determination in S802 of FIG. 34.

FIG. 41 is a graph showing a range of values of the exhaust-side pressure maximum value arrival angle difference Γ used in the determination of S904 in FIG. 35;

FIG. 42 is a system diagram showing a part of the configuration of an engine inspection device used for performing an engine inspection method according to another embodiment of the present invention.

43 shows the relationship between the crank reference signal and the exhaust-side pressure P _EX and the crank angle θ _{crank in} the normal assembly state, the cam pulley one tooth advance state, and the cam pulley one tooth delay state acquired by the engine inspection device in FIG. 42. It is a graph shown.

44 is a graph showing the relationship between the exhaust side pressure P _EX and the crank angle θ _{crank in} a normal assembly state, a cam pulley one tooth advance state, and a cam pulley one tooth delay state acquired by the engine inspection device of FIG. 42. .

45 shows the relationship between the crank reference signal and the exhaust side pressure P _EX and the crank angle θ _{crank in} the normal assembly state, the driven gear 1 tooth advanced state, and the driven gear 1 tooth delayed state acquired by the engine inspection device of FIG. 42. It is a graph shown.

46 is a graph showing the relationship between the exhaust side pressure P _EX and the crank angle θ _{crank in} the normal assembly state, the driven gear one tooth advanced state, and the driven gear one tooth delayed state, obtained by the engine inspection device of FIG. 42. .

FIG. 47 is an exhaust-side pressure maximum value arrival angle difference 場合 obtained when the advance / delay of one tooth of the cam pulley and the advance / delay of one tooth of the driven gear are obtained independently based on FIGS. 44 and 46; FIG. 7 is a table showing an example of values of an exhaust-side pressure unchanged state transition angle difference Σ, an exhaust-side pressure maximum value difference α, and an exhaust-side pressure unchanged value difference β.

[Explanation of symbols]

10, 12: piston 20: crank pulley 24, 26: cam pulley 40, 42 driven gear 48: exhaust valve 50: intake valve 60, 6
2: scissors gear 76: cylinder head 90: engine 9 to be inspected
2: Intake port 94: Intake manifold 96: Surge tank 98, 106: Pressure sensor 100: Exhaust port 102: Masking member 110, 112: A / D converter 114: Crank angle sensor 117: Judgment device 11
8 display 119: inspection control device 120: base 122:
Drive coupling 124: Drive shaft 125: Motor 134: Piston ring 136: Top ring 138: Second ring
140: Oil ring 144: Compression ring 200: OK lamp 202: NG lamp 250: Exhaust manifold

Claims (5)

[Claims] An internal combustion engine having an intake valve and an exhaust valve is rotated, and an intake-side space communicating with the intake valve outside the intake valve and an exhaust-side space communicating with the exhaust valve outside the exhaust valve. Detecting an occurrence time of a predetermined change state of at least one of the pressures and inspecting an assembly failure of the internal combustion engine based on the occurrence time. 2. A timing at which the predetermined change state of the pressure occurs is a timing at which an exhaust-side pressure, which is a pressure in the exhaust-side space, reaches a local maximum value, a timing at which the exhaust-side pressure reaches a local maximum value; The exhaust-side pressure in which the exhaust-side pressure starts to decrease from the unchanged state, the exhaust-side pressure in which the exhaust-side pressure starts to decrease from the unchanged state, the intake-side space, The intake-side pressure at which the intake-side pressure reaches the maximum value, the intake-side pressure at which the intake-side pressure starts to increase from an unchanged state in which the intake-side pressure does not change with time. 2. The method according to claim 1, comprising at least one of the following. 3. At least one of a connection passage between the exhaust valve and the exhaust manifold and a connection passage between the intake valve and the intake manifold is closed, and a space on the valve side from the closed position is connected to the exhaust space and the exhaust side space. The method according to claim 1 or 2, wherein the method is at least one of an intake-side space and an intake-side space. 4. The method according to claim 1, further comprising the step of detecting at least two of the plurality of types of assembly defects when the plurality of types of assembly defects occur simultaneously in the internal combustion engine. The method for inspecting a defective assembly of an internal combustion engine according to claim 1. 5. The assembly failure includes at least one of a valve clearance failure of the intake valve, a valve clearance failure of the exhaust valve, a phase shift between a crankshaft and a camshaft, and a lack of a compression ring.
The method for inspecting a defective assembly of an internal combustion engine according to any one of claims 1 to 4, comprising: