JP2007154697A - Method and device for diagnosing engine with variable valve train - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently diagnose in a production process the quality of a variable valve train in an engine with the variable valve train having two banks. <P>SOLUTION: While the engine 1 is rotated at a constant or an approximately constant engine speed, a first cam switching instruction to switch both the banks to a low speed cam, a second cam switching instruction to switch the first bank and the second bank to a high speed cam and the low speed cam, and a third cam switching instruction to switch the first bank and the second bank to the low speed cam and the high speed cam, are output to the variable valve trains for the first and second banks 1L, 1R. Intake pressure in a common line 3a is measured in each condition of each cam switching instruction to calculate first to third evaluation values, and the operation of the variable valve trains for the first and second banks is determined based on the calculated first to third evaluation values, thereby the engine is diagnosed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for diagnosing an engine having two banks in a production process, and more specifically, a low-speed cam and a high-speed cam that switch at least one of a lift amount of an intake valve and a valve opening / closing timing for each bank. A method for diagnosing an engine with a variable valve mechanism that can obtain an optimum output characteristic in the entire rotation range by switching the low speed cam and the high speed cam in accordance with the rotation range of the engine and changing the lift amount; The present invention relates to a diagnostic device.

  Conventionally, so-called V-type engines and horizontally opposed engines are known as engines having two banks.

  Further, as a variable valve mechanism for changing at least one of the lift amount of the intake valve and the valve opening / closing timing, for example, a low speed cam and a high speed cam are provided on the camshaft, and the rocker arm shaft is swung by the low speed cam. A low-speed rocker arm and a high-speed rocker arm that is swung by a high-speed cam are provided so as to be freely connectable. A rocker arm type is known in which the high speed rocker arm and the low speed rocker arm are connected in the high speed rotation range of the engine and the intake valve is driven by the high speed cam so that optimum output characteristics can be obtained in the whole rotation range. (For example, refer to Patent Document 1).

  As another variable valve mechanism, a direct hitting type that does not use a rocker arm is also known (see, for example, Patent Document 2).

  As shown in FIG. 5, this direct stroke type variable valve mechanism is arranged on a camshaft 101 for driving a valve between two high-speed cams 102 corresponding to each cylinder and between these high-speed cams 102. And one low-speed cam 103 provided.

  In addition, below the camshaft 101, an inverted cup-shaped direct lift valve lifter 110 composed of a disk-shaped end wall and a cylindrical side wall is vertically disposed in a guide hole 105 formed in the cylinder head 104. It is slidably inserted. The direct hitting valve lifter 110 includes an outer lifter 111 that constitutes a peripheral edge and a side wall of an end wall and reciprocates by a high speed cam 102, and an inner that constitutes a center portion of the end wall and reciprocates by a low speed cam 103. The inner lifter 112 is arranged so as to be relatively slidable in the vertical direction in a boundary hole 113 formed at the center of the end wall of the outer lifter 111.

  Inside the two end walls of the outer lifter 111 that are 180 degrees apart, the first cylinder hole 115 that extends in the radial direction, the inner end opens into the boundary hole 113 and the outer end closes, and the inner end A third cylinder hole 117 is formed in the boundary hole 113 and the outer end is also opened. A second cylinder hole 116 extending in the diameter direction and having both ends opened is formed in the inner lifter 112. ing.

  The first to third cylinder holes 115 to 117 have the same inner diameter, and the high speed cam 102 and the low speed cam 103 are in contact with the outer lifter 111 and the inner lifter 112, respectively, and the upper surface of the outer lifter 111 and the upper surface of the inner lifter 112 are Are flush with each other, the first to third cylinder holes 115 to 117 are continuous with each other on the same axis.

  In the first cylinder hole 115 and the second cylinder hole 116, a first pin 118 and a second pin 119 having the same length as each cylinder hole are inserted so as to be slidable in the left-right direction. In addition, a third pin 120 shorter than the cylinder hole is inserted into the third cylinder hole 117 so as to be slidable in the left-right direction, and a stopper 121 fixed near the outer end of the third cylinder hole 117 and A return spring 122 that constantly urges the third pin 120 toward the second pin 119 is mounted between the third pin 120 and the third pin 120.

  The first to third pins 118 to 120 have the same outer diameter, and when the upper surface of the outer lifter 111 and the upper surface of the inner lifter 112 are flush with each other, the end surfaces come into contact with each other and continue on the same axis. It can slide in the direction.

  The closed end of the first cylinder hole 115 is a high-pressure chamber 124 to which hydraulic oil is supplied. The hydraulic oil in the oil pan 125 is supplied from the oil pump 126 to the switching valve 127 and the cylinder head. 104, an oil passage 128 formed in 104, an annular groove 129 formed in the inner peripheral surface of the guide hole 105, an oil introduction recess 130 formed in the outer peripheral surface of the side wall of the outer lifter 111, and a through-hole formed in the side wall of the outer lifter 111. The oil hole 131 is sent through an oil passage. The switching valve 127 is switched by a control device (not shown) to drain the high-pressure chamber 124 in the low-speed rotation region of the engine and to connect the high-pressure chamber 124 to the oil pump 126 in the high-speed rotation region of the engine.

  The intake valve 133 is disposed so as to contact the center of the lower surface of the inner lifter 112 via the inner shim 132 for adjusting the valve clearance, and is opened and closed by the vertical movement of the inner lifter 112. A retainer 135 is attached to the intake valve 133 via a cotter 134, and the intake valve 133 is wound between the retainer 135 and the spring receiving portion 106 of the cylinder head 104. A spring 136 is provided to constantly urge the intake valve 133 toward the upper inner lifter 112 (in the valve closing direction). A lost motion spring 137 is disposed on the outer peripheral side of the valve spring 136 between the lower surface of the end wall of the outer lifter 111 and the spring receiving portion 106, and the outer lifter 111 is always moved upward, that is, in the valve closing direction. It is urged and pressed against the high-speed cam 102.

  In such a direct stroke type variable valve mechanism, as shown in FIG. 5, by switching the switching valve 127 so that the high pressure chamber 124 is drained in the low speed rotation region of the engine, the first to third pins 118 to 5 is slid leftward in FIG. 5 by the urging force of the return spring 122 and accommodated in the first to third cylinder holes 115 to 117, respectively, thereby separating the outer lifter 111 from the inner lifter 112. As shown, the intake valve 133 is opened and closed based on the shape of the low speed cam 103, the lift amount is reduced by the low speed cam 103 as compared with the high speed, and the angle section where the valve is open is relatively By reducing and retarding, the amount of overlap with the exhaust valve is reduced to stabilize engine operation and improve fuel efficiency. .

  Further, in the high speed rotation region of the engine, as shown in FIG. 7, by switching the switching valve 127 so that the high pressure chamber 124 communicates with the oil pump 126 and supplying hydraulic oil to the high pressure chamber 124, The third pins 118 to 120 are slid rightward in FIG. 7 against the urging force of the return spring 122, and the first pin 118 is passed over the first cylinder hole 115 and the second cylinder hole 116, The second pin 119 is spanned over the second cylinder hole 116 and the third cylinder hole 117, thereby connecting the outer lifter 111 and the inner lifter 112, and the intake valve 133 is based on the shape of the high speed cam 102. Open and close, increase the valve lift, and relatively increase the angle section where the valve is open and advance, overlap with the exhaust valve By increasing the reduction of pumping loss, so that improve the engine output by improving the charging efficiency.

  In the production process of an engine having such a variable valve mechanism (at least after engine assembly), the variable valve mechanism operates normally by performing a receipt operation of the produced engine, that is, an evaluation test, in order to ensure shipping quality. It is necessary to diagnose whether or not.

  As a diagnostic method, for example, a pressure sensor is attached to the intake port of each cylinder, a pressure sensor is installed in place of the ignition plug at the installation position of the ignition plug of each cylinder, or one pressure sensor is installed. Measure the pressure before and after the cam switching command to switch the intake cam while rotating the engine at a predetermined rotation speed so that the common measurement unit and the intake port of each cylinder are sequentially communicated by the switching valve. In addition, it is known that the operation of the variable valve mechanism corresponding to each cylinder is determined based on measured pressure waveforms before and after the cam switching command (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 3-43612 JP-A-6-17630 JP 2005-172593 A

  According to the diagnostic method disclosed in Patent Document 3, the quality of the variable valve mechanism corresponding to each cylinder can be individually determined, so that there is an advantage that the produced engine can be evaluated in detail.

  However, in such a diagnostic method, a pressure sensor is installed at each cylinder intake port and the position where the spark plug is attached, or a common measuring unit provided with one pressure sensor is connected to the intake port of each cylinder via a switching valve. There is a concern that the preparation of the test takes time and the efficiency of the evaluation test is reduced.

  In particular, in the case of an engine having two banks, if the variable valve mechanism in one of the banks is defective, the engine may be determined as NG, and it is not always necessary to determine whether the cylinder is good or bad.

  Accordingly, an object of the present invention made in view of such a point is to efficiently diagnose the quality of a variable valve mechanism in an engine with a variable valve mechanism having two banks in the production process, and to contribute to the improvement of engine shipping quality. Another object of the present invention is to provide a diagnostic method and a diagnostic device for an engine with a variable valve mechanism.

  The invention of the diagnostic method for an engine with a variable valve mechanism according to claim 1, which achieves the above object, has a first bank and a second bank, and a low speed cam and a high speed switching the lift amount of the intake valve in each bank. In the method for diagnosing an engine with a variable valve mechanism provided with a variable valve mechanism having a cam for variable, the variable movement of the first bank and the second bank while rotating the engine at a constant or substantially constant rotational speed. First cam switching command state in which the valve mechanism is a low-speed cam, and a second cam switching command in which the variable valve mechanism in the first bank is a high-speed cam and the variable valve mechanism in the second bank is a low-speed cam. State, and each cam switching command state of the third cam switching command state in which the variable valve mechanism of the first bank is a low speed cam and the variable valve mechanism of the second bank is the high speed cam. A pressure measurement procedure for measuring the intake pressure in the common pipe of the intake manifold connected to the intake ports of the first bank and the second bank and calculating the first evaluation value, the second evaluation value, and the third evaluation value; The operation of the variable valve mechanisms of the first bank and the second bank is determined based on the first evaluation value, the second evaluation value, and the third evaluation value calculated in the pressure measurement procedure, and And a diagnostic procedure for diagnosing the engine.

  According to a second aspect of the present invention, in the method for diagnosing an engine with a variable valve mechanism according to the first aspect, the pressure measurement procedure includes rotating the engine at a constant or substantially constant rotational speed by operating the engine, It is characterized by measuring the intake pressure under.

  According to a third aspect of the present invention, in the method for diagnosing an engine with a variable valve mechanism according to the first aspect, the pressure measurement procedure includes rotating the engine at a constant or substantially constant rotational speed by a motor, It is characterized by measuring the intake pressure under.

  According to a fourth aspect of the present invention, in the diagnostic method for an engine with a variable valve mechanism according to any one of the first to third aspects, the diagnostic procedure includes both the second evaluation value and the third evaluation value. A first determination condition that is equal to or greater than a value obtained by adding a first set value to the first evaluation value; and a second determination condition in which both the second evaluation value and the third evaluation value are within a predetermined allowable pressure range. When satisfied, the engine is diagnosed as normal, and when at least one of the first determination condition and the second determination condition is not satisfied, the engine is diagnosed as abnormal.

  According to a fifth aspect of the present invention, in the diagnosis method for an engine with a variable valve mechanism according to the fourth aspect, the upper limit value and the lower limit value of the allowable pressure range are the difference between the second evaluation value and the first evaluation value. The ratio obtained by multiplying the average value of the difference between the third evaluation value and the first evaluation value by the second set value is calculated by adding and subtracting the average value.

  Furthermore, the invention of the diagnostic device for an engine with a variable valve mechanism according to claim 6 which achieves the above object has a first bank and a second bank, and a low-speed cam for switching the lift amount of the intake valve to each bank. And a variable valve mechanism engine diagnostic apparatus provided with a variable valve mechanism having a high speed cam, and an intake pressure in a common line of intake manifolds connected to intake ports of the first bank and the second bank A pressure sensor that measures the engine speed, and a first cam switch that controls the rotational speed of the engine to a constant or substantially constant rotational speed and each of the variable valve mechanisms of the first bank and the second bank is a low-speed cam. Command, a second cam switching command in which the variable valve mechanism in the first bank is a high speed cam and the variable valve mechanism in the second bank is a low speed cam, variable in the first bank A third cam switching command is provided in which the valve mechanism is a low speed cam and the variable valve mechanism of the second bank is a high speed cam, and the first sensor is based on the output of the pressure sensor in each cam switching command state. Computation control means for diagnosing the engine by judging the operation of the variable valve mechanism of the bank and the second bank is characterized.

  According to a seventh aspect of the present invention, in the diagnostic apparatus for an engine with a variable valve mechanism according to the sixth aspect, the calculation control means controls the first engine speed while controlling the engine speed to a constant or substantially constant speed. A control unit for giving the first cam switching command, the second cam switching command, and the third cam switching command to the bank and the variable valve mechanism of the second bank; the first cam switching command state; An arithmetic unit for diagnosing the engine by determining the operation of the variable valve mechanisms of the first bank and the second bank based on the output of the pressure sensor in the two-cam switching command state and the third cam switching command state And a display unit for displaying a diagnosis result in the calculation unit.

  According to an eighth aspect of the present invention, in the diagnosis device for an engine with a variable valve mechanism according to the seventh aspect, the calculation unit includes the first cam switch command state, the second cam switch command state, and the third cam switch command. An evaluation value calculation unit that calculates a first evaluation value, a second evaluation value, and a third evaluation value based on the output of the pressure sensor in the command state, and the first evaluation value calculated by the evaluation value calculation unit, A first evaluation value storage unit, a second evaluation value storage unit and a third evaluation value storage unit for storing the second evaluation value and the third evaluation value, respectively, the first evaluation value storage unit, and the second evaluation value Operation of the variable valve mechanisms of the first bank and the second bank based on the first evaluation value, the second evaluation value, and the third evaluation value stored in the storage unit and the third evaluation value storage unit And a determination unit for diagnosing the engine by determining And butterflies.

  According to a ninth aspect of the present invention, in the diagnostic device for an engine with a variable valve mechanism according to the eighth aspect, the evaluation value calculation unit calculates the first evaluation value, the second evaluation value, and the third evaluation value. It is calculated as an average value of peak outputs of the pressure sensor in a plurality of rotation cycles of the engine.

  According to a tenth aspect of the present invention, in the diagnosis apparatus for an engine with a variable valve mechanism according to the eighth or ninth aspect, the determination unit is configured such that both the second evaluation value and the third evaluation value are the first evaluation value. When the engine satisfies the first determination condition that is equal to or greater than the value obtained by adding the first set value to the second evaluation condition and the second determination condition in which both the second evaluation value and the third evaluation value are within a predetermined allowable pressure range. The engine is diagnosed as abnormal when at least one of the first determination condition and the second determination condition is not satisfied.

  According to an eleventh aspect of the present invention, in the diagnosis device for an engine with a variable valve mechanism according to the tenth aspect, the upper limit value and the lower limit value of the allowable pressure range are differences between the second evaluation value and the first evaluation value. The ratio obtained by multiplying the average value of the difference between the third evaluation value and the first evaluation value by the second set value is calculated by adding and subtracting the average value.

  A twelfth aspect of the present invention is the diagnostic device for an engine with a variable valve mechanism according to any one of the sixth to eleventh aspects, further comprising: a rotation driving unit that rotates the engine, and the engine by the rotation driving unit. The number of rotations is controlled by the arithmetic control means.

  According to the first aspect of the present invention, the first cam switching command state in which the variable valve mechanisms of the first bank and the second bank are respectively the low speed cams while the engine is rotated at a constant or substantially constant predetermined rotational speed. A second cam switching command state in which the variable valve mechanism of one bank is a high speed cam, the variable valve mechanism of the second bank is a low speed cam, and the variable valve mechanism of the first bank is a low speed cam, the second bank In the respective cam switching command states of the third cam switching command state in which the variable valve mechanism is a high speed cam, the intake pressure in the common line of the intake manifold is measured to determine the first evaluation value, the second evaluation value, and the second evaluation value. 3 evaluation values are calculated, and based on the calculated first evaluation value, second evaluation value, and third evaluation value, the operation of the variable valve mechanisms in the first bank and the second bank is determined to diagnose the engine. So we have two banks That can be efficiently diagnosed in the production process the quality of the variable valve mechanism in the variable valve mechanism with an engine, it is possible to contribute to the improvement of the delivery quality of the engine.

  According to the invention of claim 2, since the engine can be diagnosed in an actual working state, a reliable diagnosis is possible.

  According to the invention of claim 3, since the engine is rotated by the motor, the rotation speed and the throttle opening at which the intake pressure is most likely to fluctuate can be set to be constant, and the rotation speed is stable and the accuracy is achieved in a short time. High diagnosis is possible.

  According to the invention of claim 4, when the first determination condition and the second determination condition are satisfied, the engine is diagnosed as normal, and when at least one of the conditions is not satisfied, the engine is diagnosed as abnormal at that time. It is possible to diagnose well.

  According to the invention of claim 5, the upper limit value and the lower limit value of the allowable pressure range, which are the second determination conditions, are the difference between the second evaluation value and the first evaluation value obtained from the diagnosis target engine, the third evaluation value, and the second evaluation value. Since the calculation is based on the difference from one evaluation value, the engine can be accurately diagnosed without being influenced by the individual difference of the engine.

  According to the sixth aspect of the present invention, the pressure sensor provided in the common pipe of the intake manifold connected to the intake ports of the first bank and the second bank, and the engine speed are controlled to a constant or substantially constant speed. At the same time, a predetermined cam switching command is given to the variable valve mechanisms of the first bank and the second bank, and the operations of the variable valve mechanisms of the first bank and the second bank are determined based on the output of the pressure sensor. With a simple configuration having an engine control means for diagnosing the engine, it is possible to efficiently diagnose the quality of the variable valve mechanism in the engine with the variable valve mechanism having two banks in the production process, and to improve the engine shipping quality It is possible to contribute. Moreover, since the arithmetic control means can be configured with a personal computer (PC), for example, the configuration can be further simplified. Further, if an engine control device mounted on the vehicle for controlling the engine and a separate display device are combined, a diagnosis can be made even in an actual vehicle.

  According to the seventh aspect of the present invention, the calculation control means has a calculation unit and a display unit, and the calculation unit controls the engine speed to a constant or substantially constant speed, and the variable movement of the first bank and the second bank is controlled. A predetermined cam switching command is given to the valve mechanism, the operations of the variable valve mechanisms in the first bank and the second bank are determined based on the output of the pressure sensor, and the quality of the variable valve mechanisms is diagnosed. Since the diagnosis result is displayed on the display unit, the diagnosis result can be easily recognized with a simple configuration, and it is possible to efficiently diagnose the quality of the variable valve mechanism in an engine with a variable valve mechanism. It is possible to quickly respond to the diagnosed engine.

  According to the invention of claim 8, the calculation unit includes the evaluation value calculation unit, the first to third evaluation value storage units, and the determination unit, and in the evaluation value calculation unit, the pressure sensor of the first to third cam switching command The first to third evaluation values are calculated based on the output and stored in the corresponding first to third evaluation value storage units, and the first bank is determined in the determination unit based on the stored first to third evaluation values. Since the operation of the variable valve mechanism of the second bank is determined and the engine is diagnosed, it is possible to accurately diagnose the engine with a simple configuration.

  According to the invention of claim 9, the evaluation value calculation unit calculates the first to third evaluation values as an average value of the peak output of the pressure sensor in a plurality of rotation cycles of the engine. Even if noise is suddenly superimposed on the output, the influence on the evaluation value can be reduced, and the engine can be diagnosed more accurately.

  According to the invention of claim 10, when the first determination condition and the second determination condition are satisfied, the engine is diagnosed as normal, and when at least one of the conditions is not satisfied, the engine is diagnosed as abnormal at that time. It is possible to more efficiently diagnose the quality of the variable valve mechanism in the attached engine.

  According to the eleventh aspect of the invention, the upper limit value and the lower limit value of the allowable pressure range, which are the second determination conditions, are the difference between the second evaluation value and the first evaluation value obtained from the diagnosis target engine, the third evaluation value, and the second evaluation value. Since the calculation is based on the difference from one evaluation value, it is possible to accurately diagnose the quality of the variable valve mechanism in an engine with a variable valve mechanism without being affected by individual differences between engines.

  According to the invention of claim 12, since the engine is rotated by the rotation driving means, the rotation speed and the throttle opening where the intake pressure is most likely to fluctuate can be set to be constant, and the rotation speed can be stabilized for a short time. This enables highly accurate diagnosis.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a diagnostic method and a diagnostic apparatus for an engine with a variable valve mechanism according to the present invention will be described below with reference to FIGS.

(First embodiment)
1 to 3 show a first embodiment of the present invention. FIG. 1 is a block diagram showing a schematic configuration of a diagnostic device for an engine with a variable valve mechanism, and FIG. 2 is a relationship between evaluation values and judgment conditions. FIG. 3 is a flowchart for explaining the operation of the present embodiment.

  In this embodiment, a horizontally opposed four-cylinder engine having a variable valve mechanism for changing the lift amount and valve opening / closing timing of the intake valve in the left bank 1L as the first bank and the right bank 1R as the second bank, respectively. 1, the engine 1 is actually operated (firing) after the production process, specifically, the assembly of the engine 1 is completed, and the quality of the variable valve mechanism is diagnosed under the engine operating state. The engine 1 is provided with a pressure sensor 4 for measuring an intake pressure (intake pipe pressure) in a common line 3a of the intake manifold 3 connected to the intake ports of the banks 1L and 1R on the downstream side of the throttle valve 2.

  The output of the pressure sensor 4 is amplified by the amplifier 5, then unnecessary noise components are removed by the filter circuit 6, and then converted to a digital signal such as a CAN message by the A / D converter 7 such as a CAN converter. Then, the data is taken into the arithmetic control means 8 having a personal computer (PC).

  The arithmetic control means 8 controls the throttle valve opening, the fuel injection amount, and the ignition timing so that the rotational speed of the engine 1 becomes a predetermined constant rotational speed, and the left and right banks 1L and 1R are controlled during the rotation of the engine 1. A control unit 11 that gives a cam switching command to the variable valve mechanism, a calculation unit 12 that determines the operation of the variable valve mechanism based on the intake pressure measured by the pressure sensor 4, and a determination by the calculation unit 12 A display unit 13 for displaying the result is provided.

  Here, the engine 1 is operated and rotated, for example, at a constant or substantially constant idle speed. The idling engine speed is controlled to be a constant engine speed. However, since the engine speed varies substantially, the engine engine speed is substantially constant. Measured by the pressure sensor 4 in a state where a first cam switching command is given to set the variable valve mechanisms of the left and right banks 1L, 1R to low speed cams (LO cams) under the condition of the constant or substantially constant rotational speed. The first evaluation value calculated based on the intake pressure is RL-LO, the variable valve mechanism of the left bank 1L is a high speed cam (HI cam), and the variable valve mechanism of the right bank 1R is LO cam. The second evaluation value calculated based on the intake pressure measured by the pressure sensor 4 in a state where the two-cam switching command is given is L-HI, the variable valve mechanism of the right bank 1R is the HI cam, and the left bank 1L When the third evaluation value calculated based on the intake pressure measured by the pressure sensor 4 in a state where the third cam switching command is given with the variable valve mechanism as the LO cam is given as R-HI, the left and right banks 1L, 1R The variable valve mechanism is positive 2, the first evaluation value RL-LO, the second evaluation value L-HI, and the third evaluation value R-HI are as shown in FIG. 2, for example, and RL-LO <L-HI and RL-LO <R-HI.

  That is, this mechanism will be explained. When the variable valve mechanisms of the left and right banks are both low speed cams (LO cams), the valve lift amount in each cylinder is smaller than that at the time of high speed cams (HI cams), and Since the angle section in which the valve is opened is relatively decreased and retarded, and the amount of overlap with the exhaust valve is decreased, the intake pressure is lowered due to the increase in the intake and exhaust resistance. When one of the left and right banks is switched to the high speed cam (HI cam), the cylinder of the one bank that has been switched to the high speed cam has an increased valve lift amount and the angle at which the valve is opened. As the section relatively increases and advances, the amount of overlap with the exhaust valve increases, whereby the intake pressure increases due to a decrease in the intake and exhaust resistance. These changes in intake pressure become significant at low engine speeds.

  Therefore, even if the first cam switching command is given, when the intake valve of at least one cylinder is fixed to the HI cam, for example, in the variable valve mechanism having the configuration shown in FIGS. Even if a cam switching command is issued to the low-speed cam 103 from the first pin 118, the first to third pins 118 to 120 do not return to the state of being accommodated in the first to third cylinder holes 115 to 117, respectively. Is fixed to the first cylinder hole 115 and the second cylinder hole 116, and the second pin 119 is fixed to the second cylinder hole 116 and the third cylinder hole 117. When the switching valve 6 is not switched due to the failure of the outer ring and the outer lifter 111 and the inner lifter 112 are in the connected state, the first evaluation value RL-LO is larger than when switching normally.

  Further, even when the second cam switching command is given, when the intake valve of at least one cylinder of the left bank 1L is fixed to the LO cam, for example, in the variable valve mechanism having the configuration shown in FIGS. Even when a cam switching command from the low speed cam 103 to the high speed cam 102 is issued, the first pin 118 is stretched over the first cylinder hole 115 and the second cylinder hole 116, and the second pin 119 is second. The first to third pins 118 to 120 are fixed in a state of being accommodated in the first to third cylinder holes 115 to 117, respectively, without entering the cylinder hole 116 and the third cylinder hole 117, When the outer lifter 111 and the inner lifter 112 are in a disconnected state, the second evaluation value L-HI is smaller than when switching normally.

  Similarly, even when the third cam switching command is given, if the intake valve of at least one cylinder in the right bank 1R is fixed to the LO cam, the third evaluation value R-HI is higher than when switching normally. Get smaller.

  Therefore, in the present embodiment, as shown in FIG. 1, the calculation unit 12 is provided with an evaluation value calculation unit 21, first to third evaluation value storage units 22-1 to 22-3, and a determination unit 23, and is controlled. Under the control of the unit 11, the first to third evaluation values are calculated based on the intake pressure measured by the pressure sensor 4 in the evaluation value calculation unit 21 according to the first to third cam switching commands. Each evaluation value is stored in the corresponding first to third evaluation value storage units 22-1 to 22-3.

  That is, in the evaluation value calculation unit 21, the first evaluation value is determined from the intake pressure measured by the pressure sensor 4 in a state where a first cam switching command is given in which the variable valve mechanisms of the left and right banks 1L and 1R are LO cams. RL-LO is calculated and stored in the first evaluation value storage unit 22-1, and a second cam switching command in which the variable valve mechanism of the left bank 1L is the HI cam and the variable valve mechanism of the right bank 1R is the LO cam Is calculated from the intake pressure measured by the pressure sensor 4 and stored in the second evaluation value storage unit 22-2, and the variable valve mechanism of the left bank 1L is set to LO. The third evaluation value R-HI is calculated by calculating the third evaluation value R-HI from the intake pressure measured by the pressure sensor 4 in a state where the third cam switching command is given in which the variable valve mechanism of the cam and the right bank 1R is the HI cam. Store in the value storage unit 22-3.

  The first to third evaluation values calculated by the evaluation value calculation unit 21 are preferably average values of, for example, peak outputs of the pressure sensor 4 in a plurality of rotation cycles of the engine 1 in order to reduce the influence of sudden noise. Calculate as

  The determination unit 23 operates the variable valve mechanisms of the left and right banks 1L and 1R based on the first to third evaluation values stored in the first to third evaluation value storage units 22-1 to 22-3, that is, cams. The engine 1 is diagnosed by determining the switching situation, and the diagnosis result is displayed on the display unit 13.

  Hereinafter, the operation of the engine diagnosis apparatus of the present embodiment will be described with reference to the flowchart shown in FIG.

  First, the operation of the engine 1 is started, and the throttle valve opening, fuel injection amount, and ignition timing are controlled by the control unit 11 so that the engine speed is constant or substantially constant (in this embodiment, idle speed). The control unit 11 gives a first cam switching instruction with the variable valve mechanisms of the left and right banks 1L and 1R as LO cams, respectively, and based on the output of the pressure sensor 4 in the first cam switching command state The evaluation value calculation unit 21 calculates the first evaluation value RL-LO and stores it in the first evaluation value storage unit 22-1 (step S1).

  Thereafter, the variable valve mechanism of the right bank 1R remains the LO cam from the control unit 11, and a second cam switching command for switching only the variable valve mechanism of the left bank 1L to the HI cam is given. Based on the output of the pressure sensor 4 at, the evaluation value calculation unit 21 calculates the second evaluation value L-HI and stores it in the second evaluation value storage unit 22-2 (step S2).

  Next, the control unit 11 gives a third cam switching command to leave the variable valve mechanism of the left bank 1L as the LO cam and the variable valve mechanism of the right bank 1R as the HI cam. Based on the output of the pressure sensor 4 at, the evaluation value calculation unit 21 calculates the third evaluation value R-HI and stores it in the third evaluation value storage unit 22-3 (step S3).

  Thus, after storing the first evaluation value RL-LO, the second evaluation value L-HI, and the third evaluation value R-HI in the first to third evaluation value storage units 22-1 to 22-3, Based on the first evaluation value RL-LO, the second evaluation value L-HI, and the third evaluation value R-HI, the determination unit 23 diagnoses the engine 1.

  First, whether or not both the second evaluation value L-HI and the third evaluation value R-HI are equal to or greater than a value obtained by adding the first setting value Pref1 to the first evaluation value RL-LO satisfies the first determination condition. judge.

  Therefore, here, first, using the second evaluation value L-HI, the first evaluation value RL-LO, and the first set value Pref1, whether {(L-HI)-(RL-LO)} ≧ Pref1 or not. That is, it is determined whether or not the relative intake pressure when the variable valve mechanism of the left bank 1L is the HI cam is equal to or higher than Pref1 (step S4). If NO, the engine NG is determined because the left bank 1L is defective. (Step S5), the result is displayed on the display unit 13, and the diagnosis process is terminated.

  On the other hand, in step S4, if {(L-HI)-(RL-LO)} ≧ Pref1 (in the case of Yes), next, the third evaluation value R-HI and the first evaluation value RL-LO Using the first set value Pref1, whether or not {(R−HI) − (RL−LO)} ≧ Pref1, that is, the relative intake pressure when the variable valve mechanism of the right bank 1R is the HI cam is Pref1. It is determined whether or not it is above (step S6). If the answer is No, the right bank 1R is defective. Therefore, the engine NG is diagnosed in step S5, the result is displayed on the display unit 13, and the diagnosis process is terminated. To do.

  Here, the first set value Pref1 is {(L-HI)-(RL-LO)} and {(R-HI) for a plurality of normal engines of the same type as the design data and the engine 1 to be diagnosed. Based on the actually measured value of-(RL-LO)}, for example, 25 (mmHg) is set as shown in FIG.

  On the other hand, in step S6, if {(R-HI)-(RL-LO)} ≧ Pref1 (in the case of Yes), next, the second evaluation value L-HI and the third evaluation value R- It is determined whether or not the second determination condition that both of the HI values are within a predetermined allowable pressure range is satisfied.

  Therefore, first, using the second evaluation value L-HI, the third evaluation value R-HI, and the second set value α, the second evaluation value L-HI and the third evaluation value R-HI shown in FIG. An upper limit value Pmax and a lower limit value Pmin of the allowable pressure range are calculated (step S7).

  In the present embodiment, in consideration of individual differences of the engine 1, Pmax and Pmin are calculated as ± α centered on the average value of the second evaluation value L-HI and the third evaluation value R-HI. Here, α is, for example, 0.2. Accordingly, in step S7, [{(L−HI) + (R−HI)} / 2] (1 ± 0.2) is calculated to calculate Pmax and Pmin.

  Thereafter, it is determined whether Pmin ≦ (L−HI) ≦ Pmax (step S8). If the result is No, the left bank 1L is defective. In step S5, engine NG is diagnosed, and the result is displayed on the display unit 13. And the diagnosis process is terminated. If Yes, it is next determined whether Pmin ≦ (R−HI) ≦ Pmax (step S9). As a result, in the case of No, the right bank 1R is defective, so that the engine NG is diagnosed in step S5, the result is displayed on the display unit 13 and the diagnosis process is terminated. OK is diagnosed (step S10), the result is displayed on the display unit 13, and the diagnosis process is terminated.

  As described above, according to the present embodiment, the engine speed is controlled to a constant or substantially constant speed (idle speed) under the control of the arithmetic control means 8 configured to operate the engine 1 and have a PC. The left and right banks 1L and 1R, the first valve switching command to make each variable valve mechanism a low-speed cam, the left bank 1L variable valve mechanism to be a high-speed cam and the right bank 1R A second cam switching command is set to use the variable valve mechanism as a low-speed cam, and a third cam switching command is set to use the variable valve mechanism in the left bank 1L as a low-speed cam and the variable valve mechanism in the right bank 1R as a high-speed cam. Then, the intake pressure in the common line of the intake manifold in each cam switching command state is measured by the pressure sensor 4 to calculate the first evaluation value, the second evaluation value, and the third evaluation value, and the calculated first Evaluation value, second evaluation value and 3 Since the engine 1 is diagnosed by determining the operation of the variable valve mechanisms in the left and right banks 1L and 1R based on the evaluation values, the engine 1 with the variable valve mechanism in the left and right banks 1L and 1R has a simple configuration. The quality of the variable valve mechanism can be efficiently diagnosed during the production process, and the engine shipping quality can be improved.

  Further, since the diagnosis result of the engine 1 is displayed on the display unit 13, the diagnosis result can be easily recognized, and a quick response when an abnormality is diagnosed can be realized.

(Second Embodiment)
FIG. 4 is a block diagram showing a schematic configuration of a diagnostic apparatus for an engine with a variable valve mechanism according to a second embodiment of the present invention.

  In the present embodiment, in the first embodiment, a motor 25 as rotational drive means is connected to the crankshaft of the engine 1 with a variable valve mechanism to be diagnosed, and the motor 25 is controlled by the control unit 11 to be used in the engine. The engine 1 is rotated at a constant rotational speed and the engine 1 is diagnosed by a so-called cold test. Other configurations and operations are the same as those in the first embodiment, and thus description thereof is omitted here.

  According to the present embodiment, in addition to the effects of the first embodiment, the variable valve operation in the engine 1 with the variable valve mechanism having the left and right banks 1L and 1R by a cold test in which the engine 1 is rotated using the motor 25. Since the quality of the mechanism is diagnosed during the production process, the engine 1 can be set to a constant rotation speed and throttle opening where the intake pressure is most likely to fluctuate, and the rotation speed is stable and high accuracy in a short time. Diagnosis is possible.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the present invention can be widely applied to an engine with a variable valve mechanism having two banks regardless of the type such as the horizontally opposed type or the V type, and regardless of the number of cylinders.

  Furthermore, the present invention can be applied to any variable valve mechanism as long as it switches at least one of the lift amount of the intake valve and the valve opening / closing timing. Further, the engine speed at the time of diagnosis is not limited to the idle speed.

  Further, the first to third evaluation values are not limited to being calculated as an average value of the peak output of the pressure sensor 4 in a plurality of rotation cycles, but may be calculated as an integral value or calculated as an addition value of the peak output. The value can be determined by an arbitrary calculation method based on the output of the pressure sensor 4.

  Furthermore, the arithmetic control means is not limited to a personal computer, and may be a dedicated diagnostic device. Further, an engine control device mounted on the vehicle for controlling the engine and a separate display device may be combined. In this case, diagnosis can be performed even in an actual vehicle.

  The above-described production process refers to the period from after assembly of the engine or after the engine is mounted on the vehicle to shipment from the factory.

1 is a block diagram showing a schematic configuration of a diagnostic device for an engine with a variable valve mechanism according to a first embodiment of the present invention. It is a figure which shows the relationship between an evaluation value and determination conditions. It is a flowchart explaining operation | movement of 1st Embodiment. It is a block diagram which shows schematic structure of the diagnostic apparatus of the engine with a variable valve mechanism by 2nd Embodiment of this invention. It is sectional drawing which shows the structure of an example of the variable valve mechanism which can be diagnosed by this invention. It is a fragmentary sectional view in the low speed rotation area of the variable valve mechanism shown in FIG. Similarly, it is a partial sectional view in a high-speed rotation region.

Explanation of symbols

1 Engine 1L Left bank (1st bank)
1R Right bank (second bank)
DESCRIPTION OF SYMBOLS 3 Intake manifold 3a Common pipe 4 Pressure sensor 8 Calculation control means 11 Control part 12 Calculation part 13 Display part 21 Evaluation value calculation part 22-1 to 22-3 1st-3rd evaluation value memory | storage part 23 Determination part 25 Motor

Claims (12)

With a variable valve mechanism having a first valve and a second bank, each bank having a variable valve mechanism having a low speed cam and a high speed cam for switching at least one of the lift amount of the intake valve and the valve opening / closing timing In the engine diagnosis method,
A first cam switching command state in which the variable valve mechanisms of the first bank and the second bank are respectively low speed cams while the engine is rotated at a constant or substantially constant rotational speed, and the variable movement of the first bank. A second cam switching command state in which the valve mechanism is a high-speed cam and the variable valve mechanism in the second bank is a low-speed cam, and the variable valve mechanism in the first bank is a low-speed cam and the second bank is enabled. In each cam switching command state of the third cam switching command state where the variable valve mechanism is a high speed cam, the intake pressure in the common pipe of the intake manifold connected to the intake port of the first bank and the second bank is A pressure measurement procedure for measuring and calculating a first evaluation value, a second evaluation value, and a third evaluation value;
Based on the first evaluation value, the second evaluation value, and the third evaluation value calculated in the pressure measurement procedure, the operation of the variable valve mechanisms in the first bank and the second bank is determined to determine the engine. And a diagnostic procedure for diagnosing the engine with a variable valve mechanism. The pressure measurement procedure is as follows:
2. The method for diagnosing an engine with a variable valve mechanism according to claim 1, wherein the engine is rotated at a constant or substantially constant rotational speed by operating the engine, and the intake pressure is measured under each switching command state. The pressure measurement procedure is as follows:
2. The method for diagnosing an engine with a variable valve mechanism according to claim 1, wherein the engine is rotated at a constant or substantially constant rotational speed by a motor, and the intake pressure is measured under each switching command state. The diagnostic procedure is
Both the second evaluation value and the third evaluation value are equal to or greater than a value obtained by adding the first set value to the first evaluation value, and both the second evaluation value and the third evaluation value. The engine is diagnosed as normal when the second determination condition within a predetermined allowable pressure range is satisfied, and the engine is diagnosed as abnormal when at least one of the first determination condition and the second determination condition is not satisfied. The diagnostic method for an engine with a variable valve mechanism according to any one of claims 1 to 3. The upper and lower limits of the allowable pressure range are
The ratio obtained by multiplying the average value of the difference between the second evaluation value and the first evaluation value and the difference between the third evaluation value and the first evaluation value by the second set value is defined as the average value. 5. The method for diagnosing an engine with a variable valve mechanism according to claim 4, wherein calculation is performed by addition and subtraction. With a variable valve mechanism having a first valve and a second bank, each bank having a variable valve mechanism having a low speed cam and a high speed cam for switching at least one of the lift amount of the intake valve and the valve opening / closing timing In the engine diagnostic device,
A pressure sensor for measuring an intake pressure in a common line of the intake manifold connected to the intake ports of the first bank and the second bank;
The engine speed is controlled to be constant or substantially constant, and the first bank switching command for setting the variable valve mechanisms of the first bank and the second bank to low-speed cams, respectively, A second valve switching command in which the variable valve mechanism is a high-speed cam and the variable valve mechanism in the second bank is a low-speed cam, and the variable valve mechanism in the first bank is a low-speed cam and the second bank is allowed. The operation of the variable valve mechanisms in the first bank and the second bank is performed based on the output of the pressure sensor in each cam switching command state by giving a third cam switching command using the variable valve mechanism as a high speed cam. And an arithmetic control means for diagnosing the engine by judging the above. The arithmetic control means is
While controlling the engine speed to a constant or substantially constant speed, the first cam switching command, the second cam switching command, and the first bank switching command for the variable valve mechanisms in the first bank and the second bank are controlled. A control unit for giving a three-cam switching command;
Based on the output of the pressure sensor in the first cam switching command state, the second cam switching command state, and the third cam switching command state, the variable valve mechanisms of the first bank and the second bank are operated. A calculation unit for determining and diagnosing the engine;
The diagnostic apparatus for an engine with a variable valve mechanism according to claim 6, further comprising: a display unit that displays a diagnosis result of the arithmetic unit. The arithmetic unit is
A first evaluation value, a second evaluation value, and a third evaluation value are calculated based on the output of the pressure sensor in the first cam switching command state, the second cam switching command state, and the third cam switching command state, respectively. An evaluation value calculation unit to perform,
A first evaluation value storage unit, a second evaluation value storage unit, and a third evaluation value storage unit that store the first evaluation value, the second evaluation value, and the third evaluation value calculated by the evaluation value calculation unit; ,
Based on the first evaluation value, the second evaluation value, and the third evaluation value stored in the first evaluation value storage unit, the second evaluation value storage unit, and the third evaluation value storage unit, 8. The diagnosis apparatus for an engine with a variable valve mechanism according to claim 7, further comprising a determination unit that determines the operation of the bank and the variable valve mechanism of the second bank to diagnose the engine. The evaluation value calculation unit
9. The first evaluation value, the second evaluation value, and the third evaluation value are calculated as average values of peak outputs of the pressure sensor in a plurality of rotation cycles of the engine. Engine diagnostic device with variable valve mechanism. The determination unit is
Both the second evaluation value and the third evaluation value are equal to or greater than a value obtained by adding the first set value to the first evaluation value, and both the second evaluation value and the third evaluation value. The engine is diagnosed as normal when the second determination condition within a predetermined allowable pressure range is satisfied, and the engine is diagnosed as abnormal when at least one of the first determination condition and the second determination condition is not satisfied. The diagnostic device for an engine with a variable valve mechanism according to claim 8 or 9, wherein: The upper and lower limits of the allowable pressure range are
The ratio obtained by multiplying the average value of the difference between the second evaluation value and the first evaluation value and the difference between the third evaluation value and the first evaluation value by the second set value is defined as the average value. 11. The diagnostic apparatus for an engine with a variable valve mechanism according to claim 10, wherein calculation is performed by addition and subtraction. The variable motion according to any one of claims 6 to 11, further comprising: a rotation driving means for rotating the engine, wherein the rotational speed of the engine by the rotation driving means is controlled by the arithmetic control means. Diagnosis device for engine with valve mechanism.

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