JP4014426B2 - Exhaust valve opening timing detection device for the engine under test - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust valve opening timing detection apparatus in a test target engine.
[0002]
[Prior art]
Recently, when detecting the opening timing of the exhaust valve in the engine, by supplying fuel to the test target engine and actually burning it, by rotating the crankshaft by external drive means, A cold test may be performed to detect the opening timing of the exhaust valve. In such a cold test, the intake valve opening / closing timing, the exhaust valve closing timing, and the like may also be detected.
[0003]
By the way, in the cold test as described above, for example, an engine test is performed by rotating the crankshaft by an external drive means even for an engine in the middle of assembly where a fuel injection nozzle, a spark plug or the like is not yet mounted. Therefore, even if it is necessary to carry out a rework work by the engine test, it is possible to reduce the cost by reducing the number of rework steps.
[0004]
As a configuration for detecting the opening timing of the exhaust valve in the test target engine by such a cold test, conventionally, as shown in, for example, Japanese Patent Publication No. 2-55738, the cylinder internal space in the test target engine is reduced. In order to detect the pressure change in the exhaust port, with air being released from the atmosphere and supplying air via an regulator from an air supply source provided outside the engine toward the exhaust port provided in the cylinder In the state where the crankshaft is rotated by the external drive means, the phase at which the pressure in the exhaust port suddenly changes is determined based on the detection information of the pressure detection means. There was something configured to detect as.
[0005]
[Problems to be solved by the invention]
By the way, an exhaust manifold for exhausting combustion exhaust gas to the outside with respect to the exhaust port is assembled to the engine. In the conventional configuration, the exhaust manifold is provided outside the engine toward the exhaust port. Since air is supplied from an air supply source via a regulator, the exhaust valve opening timing cannot be detected when the above-described exhaust manifold is already assembled.
Further, in the above-described conventional configuration, in order to stably supply air to the exhaust port, for example, an air supply source that becomes a large-sized device including a compressor and an electric motor for driving the compressor is necessary. There is a disadvantage that the air supply source that outputs the compressed air and the engine are connected by piping, and there is a disadvantage that the safety in work may be lowered.
Furthermore, since the air supply source, which is a large device as described above, is installed at a location away from the engine to be tested, the air supply source and the exhaust port are connected by a long air supply pipe. In addition, it is necessary to separately provide a pressure detection means in the exhaust port, and these troublesome operations are required, and there is a disadvantage that the work time when detecting the opening timing of the exhaust valve is long and the work efficiency is lowered.
[0006]
The present invention has been made paying attention to such a point, and an object of the present invention is to solve the disadvantages of the conventional configuration as described above and to detect the opening timing of the exhaust valve satisfactorily. The present invention provides an exhaust valve open timing detection device.
[0007]
[Means for Solving the Problems]
The exhaust valve opening timing detection device for a test target engine according to claim 1 is connected to the crankshaft of the test target engine assembled so that the intake valve and the exhaust valve are opened and closed as the crankshaft rotates. An external driving means for forcibly rotating the crankshaft, a rotational phase detecting means for detecting the rotational phase of the crankshaft, a pressure detecting means for detecting the pressure in the cylinder of the engine under test, A one-way flow forming means connected to a cylinder of the engine to be tested, allowing the outflow of air from the inside of the cylinder and preventing the inflow of air from the outside into the cylinder; and the external driving means The detection information of the pressure detection means and the rotation phase detection means in a state where the crankshaft is rotated at Based on the detection information, the rotational phase of the pressure in the cylinder is changed to increasing tendency from decreasing, characterized in that it is constituted by a timing detection means for detecting as an open timing of the exhaust valve.
[0008]
That is, in the state where the crankshaft of the engine under test in which the intake valve and the exhaust valve are assembled is rotated by the external drive means, the rotation phase detection means detects the rotation phase of the crankshaft and the pressure detection means The pressure in the cylinder is detected, and based on the detected information, the rotation phase at which the pressure in the cylinder changes from a decreasing tendency to an increasing tendency is detected as the exhaust valve opening timing. When the crankshaft is rotated by the external drive means, the engine under test is allowed to flow out of air from the cylinder to the outside by the one-way flow forming means, and the air from the outside to the cylinder is allowed to flow. Inflow is blocked. Note that the intake port and the exhaust port are open to the outside in the same manner as in a normal operation state.
[0009]
In other words, when the crankshaft is rotated by the external driving means, the intake stroke in which the piston under test in the cylinder under test with the intake valve opened and the air is sucked into the cylinder from the intake port, A compression stroke in which the piston rises in the cylinder and compresses the air in the cylinder with the intake valve and exhaust valve closed, and the piston descends and the air in the cylinder expands with the intake valve and exhaust valve closed The expansion stroke and the exhaust stroke in which the piston rises in the cylinder and the air in the cylinder is discharged from the exhaust port while the exhaust valve is open are executed.
In the intake stroke, since the intake valve is opened, the pressure in the cylinder is almost equal to the atmospheric pressure, and in the compression stroke, the air in the cylinder is compressed as the piston rises. However, since the air flows out from the inside of the cylinder to the outside by the one-way flow forming means, the pressure in the cylinder hardly rises and is almost equal to the atmospheric pressure. In the expansion stroke, both the intake valve and the exhaust valve are in a closed state, and the one-way flow forming means prevents the inflow of air from the outside into the cylinder. The pressure inside the piston becomes lower than the atmospheric pressure, and the pressure becomes lower as the descending amount from the compression top dead center of the piston becomes larger. In the exhaust stroke, since the exhaust valve is opened, air flows into the piston from the outside, and the pressure inside the cylinder starts to rise.
[0010]
Before the exhaust valve opens, that is, in the expansion stroke, the pressure in the cylinder tends to decrease as the piston descends. Air begins to flow in, and the internal pressure of the cylinder changes to an upward trend. Thus, the rotation phase at which the pressure in the cylinder changes from a decreasing tendency to an increasing tendency can be detected as the exhaust valve opening timing.
[0011]
Therefore, the exhaust port is opened to the outside in the same manner as in a normal operation state, and only exhausts the air in the cylinder. Therefore, even if the exhaust manifold is already assembled in the exhaust port, the exhaust port is exhausted. The opening timing of the valve can be detected satisfactorily. In addition, the air supply source is a large-sized device because it can be dealt with by simply connecting the pressure detecting means, which is not a large device like a large air supply device, and a simple one-way flow forming means to the cylinder. Compared to the above-described conventional configuration including the above, it is possible to cope with a simple configuration and to improve the operational safety because a device for generating compressed air such as an air supply source is not used. In addition, the work time when detecting the opening timing of the intake valve without requiring the troublesome work of connecting the air supply source located far from the engine to be tested and the exhaust port of the engine with a long air supply pipe It became possible to improve work efficiency by shortening.
As a result, it has become possible to provide an exhaust valve opening timing detection device in an engine to be tested that can eliminate the disadvantages of the conventional configuration and can detect the opening timing of the exhaust valve satisfactorily.
[0012]
The exhaust valve opening timing detection device for the engine to be tested according to claim 2 is the one according to claim 1, wherein the timing detection means is configured to change the pressure in the cylinder from a decreasing tendency to an increasing tendency. When determining that the amount of change per unit time has reached the set value, and determining that the amount of change of the pressure per unit time has reached the set value in the increased state determining process, A phase calculation process for obtaining a rotation phase on the upper side in the rotation direction by a set amount from the rotation phase when the change amount becomes a set value is obtained as a rotation phase that changes from the decreasing tendency to the rising tendency. It is characterized by being.
[0013]
As described above, when the exhaust valve is opened, the internal pressure of the cylinder rises. Therefore, the time when the internal pressure changes from a decreasing tendency to an increasing tendency is the opening timing of the exhaust valve. It is difficult to accurately detect, in real time, the point in time when the pressure starts to increase with the opening, based on the detection result of the pressure detection value. When the explanation is added based on the experimental data by the present applicant, as shown in FIG. 11, the pressure immediately after the time point (X2) at which the internal pressure of the cylinder changes from the decreasing tendency to the increasing tendency by opening the exhaust valve. The detection value is a gradual change, and it is difficult to accurately detect when the pressure starts to increase with the opening of the exhaust valve in real time based on the detection result of the pressure detection value. However, if a little time has elapsed after the time point (X2) when the internal pressure changes from a decreasing tendency to an increasing tendency, whether or not the rate of change of the pressure in the cylinder has reached the set value is relatively It is easy to detect with high accuracy.
[0014]
Therefore, the rotational phase at the time point (X1) when the amount of change per unit time after the internal pressure has changed from the decreasing tendency to the increasing tendency has been set, is obtained, and the upper side in the rotational direction by the set amount from the rotational phase. Is determined as a rotational phase that changes from a decreasing tendency to an increasing tendency.
[0015]
Thus, the rotational phase at which the internal pressure of the cylinder changes from a decreasing tendency to an increasing tendency can be detected as accurately as possible corresponding to the opening timing of the exhaust valve. Suitable means are obtained.
[0016]
The exhaust valve opening timing detection device in the engine to be tested according to claim 3 is the one according to claim 1 or 2, wherein the timing detection means sets a pressure detection value detected by the pressure detection means. In addition to sampling every period, a moving average value for each set number of the sampled sampling values is obtained, and a rotation phase at which the moving average value changes from a decreasing tendency to an increasing tendency is detected as the opening timing of the exhaust valve. It is characterized by being comprised.
[0017]
That is, since the moving average value is obtained for each set number of sampling values for the pressure detection values sampled at each set cycle, for example, the pressure detection value detected by the pressure detection means is caused by disturbance. Even if a value that changes greatly temporarily is detected, the detected value is averaged and averaged by obtaining the moving average value. Therefore, it is possible to suppress the occurrence of errors due to this, and to obtain a suitable means for implementing the first or second aspect.
[0018]
The exhaust valve open timing detection device for a test target engine according to claim 4 is the one according to any one of claims 1 to 3, wherein the pressure detection means reduces the pressure of the cylinder of the test target engine. It is comprised so that it may be connected through the buffer part for the purpose.
[0019]
In other words, in order to detect the internal pressure of the cylinder, it is necessary to connect the pressure detecting means to the cylinder. At this time, the pressure detecting means is connected via a buffer for reducing pressure. In other words, when the crankshaft is forcibly rotated by the external drive means, the difference between the internal pressure of the cylinder and the atmospheric pressure is increased by the operation of the piston, but the crankshaft is connected via the buffer for reducing pressure. Therefore, the large pressure difference is reduced by the buffer for reducing pressure. Even if the pressure is not an absolute value but a reduced pressure, it is possible to detect a rotation phase at which the internal pressure of the cylinder changes from a decreasing tendency to an increasing tendency.
[0020]
Therefore, it is possible to avoid the disadvantage that the connection portion between the pressure detection means and the cylinder is damaged or disconnected due to the large pressure difference as described above, and any one of claims 1 to 3 is implemented. Means suitable for doing so are obtained.
[0021]
The exhaust valve opening timing detection device for the test target engine according to claim 5 is the hose connected to the cylinder of the test target engine, wherein the buffer for pressure reduction is the one according to claim 4, The hose is equipped with the pressure detecting means and the one-way flow forming means in parallel.
[0022]
That is, since the pressure detecting means and the one-way flow forming means are provided in parallel in the hose as the pressure reducing buffer portion, when detecting the opening timing of the exhaust valve, This can be handled by a simple operation of connecting the hose to the cylinder, and means suitable for carrying out the present invention can be obtained.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an engine test apparatus including an exhaust valve opening timing detection apparatus in a test target engine according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, this engine test apparatus is connected to a crankshaft 4 of a test target engine 1 attached to a pallet P, and has an external drive means including an electric motor 2 for forcibly rotating the crankshaft 4. 3. The encoder 5 as a rotation phase detecting means for detecting the rotation phase of the crankshaft 4 by detecting the rotation of the crankshaft 4; the rotation speed of the electric motor 2 is controlled; The control unit H is configured to test whether or not the timing of opening / closing operation of the intake valve and the exhaust valve is appropriate based on detection information of various sensors S and encoders as will be described later.
[0024]
The encoder 5 outputs a reference signal of one pulse every time the crankshaft 4 makes one rotation to be a reference for the rotation phase, and outputs a pulse one by one every time the crankshaft 4 rotates by a predetermined unit angle. Is configured to output. This timing pulse is output at 3600 pulses per revolution.
[0025]
In this engine test apparatus, the engine 1 to be tested is transported to a predetermined test setting position by a transport device such as a conveyor while being mounted on the pallet P, and rotation of the electric motor 2 in the external drive means 3 is performed by an operator. The shaft 2a is connected to the crankshaft 4 via a connecting tool CP. When the test target engine 1 is thus transported to the test setting position, a test given in advance with a barcode is performed. The identification information ID for management of the target engine is read by the barcode sensor 30, and the identification information ID is input to the control unit.
The external drive means 3 is configured to be switchable between a state in which the crankshaft 4 is rotated in the normal rotation direction and a state in which the crankshaft 4 is rotated in the reverse rotation direction, and can rotate the crankshaft 4 at different rotational speeds. It can be configured.
[0026]
Then, with the external drive means 3 connected in this manner, the control unit H controls the rotational speed of the electric motor 2 to be the rotational speed for testing based on the operation command, and the electric motor 2 By forcibly rotating the crankshaft 4 by the rotational operation, the piston 7 is moved up and down and the intake valve 9 and the exhaust valve 10 are opened and closed as shown in FIG. Then, an expansion stroke and an exhaust stroke are sequentially repeated, and a cold test is performed in which various engine tests such as opening and closing timings of the intake valve 9 and the exhaust valve 10 are performed without actually burning.
[0027]
In this engine test apparatus, when performing the above-described cold test, the compression top dead center of the test target engine 1 becomes a reference for various measurements. The compression top dead center TDC of the reference cylinder 6a is obtained, and the opening and closing timing of the intake valve 9 and the exhaust valve 10 mounted on each cylinder 6 is measured using the compression top dead center of the reference cylinder 6a as a reference point. The success / failure of the engine to be tested is determined depending on whether the opening / closing timing is within an appropriate range.
[0028]
As shown in FIG. 2, the test target engine 1 is a four-cylinder four-cycle diesel engine, and includes a crankshaft 4 connected to a piston 7 of each cylinder 6 via a connecting rod 8, an intake valve 9, and A camshaft 11 having a cam for opening and closing the exhaust valve 10 is provided, and the crankshaft 4 and the camshaft 11 are connected by a gear-type interlocking mechanism 12. The gear-type interlocking mechanism 12 rotates a crankshaft gear 12a provided on the crankshaft 4 and a camshaft gear 12c provided on the camshaft 11 in an interlocking manner by meshing the gears via a relay gear 12b. The number of gear teeth is set so that when the crankshaft 4 rotates twice, the camshaft 11 rotates once in the same direction.
As the crankshaft 4 rotates, the piston 7 of each cylinder 6 is moved up and down, and the camshaft 11 is rotated to open and close the intake valve 9 and the exhaust valve 10. Note that a fuel injection nozzle for injecting fuel into the cylinder is not mounted at this test stage. And it is the structure which connects the pressure sensors 14 and 15 which are one of sensors using the mounting hole 13 for mounting | wearing with this fuel-injection nozzle.
[0029]
The connection configuration of the pressure sensors 14 and 15 will be described. As shown in FIG. 3, the reference cylinder 6a has a length of about 800 to about the mounting hole 13 using a connection jig 16. A hydraulic hose 17 having a length of about 900 mm is connected, and the two pressure sensors 14 and 15 can be selectively communicated with each other via an electromagnetically operated flow path switching valve 18 at the tip of the hydraulic hose 17. It is configured to connect. The pressure sensors 14 and 15 are connected through the hydraulic hose 17 in this way because the pressure in the cylinder becomes high pressure so that the connection location is not accidentally disconnected or damaged during inspection work. In addition, a hydraulic hose that is excellent in flexibility and easy to work with is used to exhibit a buffering function to reduce the high pressure in the cylinder. That is, the hydraulic hose 17 functions as a pressure reducing buffer.
[0030]
One of the two pressure sensors 14, 15 is configured to detect the pressure in the reference cylinder 6a connected through the hydraulic hose 17 as it is, and detects the compression top dead center of the reference cylinder 6a. The configuration is used for processing. Further, a check valve 19 is connected in parallel to the other pressure sensor 15.
For the other three cylinders 6 other than the reference cylinder 6 a, as shown in FIG. 4, the same check as the other pressure sensor 15 is provided at the tip of the hydraulic hose 17 connected to the mounting hole 13. The pressure sensor 15 provided with the valve 19 is connected. The pressure sensor 15 is used for processing for detecting the opening timing of the exhaust valve 10. Therefore, the pressure sensor 15 functions as a pressure detection means for detecting the pressure in the cylinder of the test target engine. The check valve 19 allows the flow of air from the detection target portion of the pressure sensor 15, that is, the cylinder 6 of the test target engine 1 to the outside, and prevents the flow of air from the outside into the cylinder. It will function as a unidirectional flow forming means. Therefore, when the piston 7 is compressed as the crankshaft 4 is rotationally driven by the external drive means 3, the air pushed out from the cylinder 6 flows out through the check valve 19, but the piston 7 expands and operates. Since air does not flow in from the outside, the inside of the cylinder 6 is in a low pressure state lower than the atmospheric pressure, a so-called negative pressure state.
Further, the check valve 19 and the pressure sensor 15 are equipped in a state of being connected to the hydraulic hose 17 in a parallel state, and the hydraulic hose 17 is connected to the mounting hole 13 for mounting the fuel injection nozzle. There is no need to bother connecting them individually to the cylinder 6, and the connection work can be performed efficiently.
[0031]
Next, a processing procedure by the engine test apparatus will be described.
As shown in FIG. 5, the engine 1 to be tested is transported to the test setting position, and the external drive means 3 is connected to the crankshaft 4 (step 1). At this time, the identification information ID for management of the test target engine 1 is read, and the identification information ID is input to the control unit H (step 2). When the connection work of the external drive means 3 is completed and the worker commands the start of detection, the control unit H executes a detection process of the compression top dead center TDC (hereinafter abbreviated as a TDC detection process) (step). 3). When the TDC detection process ends, the valve timing is detected with reference to the compression top dead center TDC. That is, a process for detecting the opening timing of the intake valve 9, a process for detecting the closing timing of the intake valve 9, and a process for detecting the opening timing of the exhaust valve 10 are executed. The process which determines the pass / fail of the test object engine 1 by whether it is an appropriate state is performed (steps 4-7).
[0032]
When the control unit H executes the TDC detection process, the pressure detection value detected by the pressure sensor 14 in a state where the crankshaft 4 is rotated in the normal rotation direction by the external driving means 3. The rotation phase of the crankshaft when the pressure in the cylinder reaches the maximum value in one cycle of the engine to be tested is obtained as the first preliminary compression top dead center, and the external drive means 3 In the state in which 4 is rotated in the reverse rotation direction, the rotation phase of the crankshaft 4 when the pressure in the cylinder reaches the maximum value in one cycle is determined based on the pressure detection value detected by the pressure sensor 14. Further, the rotational phase of the crankshaft 4 positioned at the center between the first preliminary compression top dead center and the second preliminary compression top dead center is determined as the second preliminary compression top dead center. As a point It is configured to. Here, the one cycle corresponds to a period in which the engine to be tested executes each stroke of the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke as the crankshaft 4 rotates. That is, the crankshaft rotates twice during this one cycle.
[0033]
In addition, when the first preliminary compression top dead center is obtained and when the second preliminary compression top dead center is obtained, the pressure detection value detected by the pressure sensor 14 is sampled every set period. At the same time, a moving average value is obtained for each set number of sampled sampling values, and the rotational phase of the crankshaft 4 when the moving average value reaches the maximum value in one cycle is determined in the cylinder. The rotation phase of the crankshaft 4 when the pressure reaches the maximum value is obtained.
[0034]
Next, the TDC detection processing by the control unit will be described based on the flowchart shown in FIG.
First, prior to this detection process, as shown in FIG. 9A, the flow path switching valve 18 is switched so that the pressure sensor 14 is connected to the inside of the cylinder. Then, the crankshaft 4 is rotated in the normal rotation direction (hereinafter referred to as the forward rotation direction) by the external driving means 3, and the rotation speed of the crankshaft 4 is rotated 60 times per minute based on the detection information of the encoder 5. The speed is controlled so as to be the rotational speed (60 rpm) (step 31). In a state of rotating in the forward direction at such a set speed, the pressure detection value in the pressure sensor 14 connected to the cylinder of the reference cylinder 6a is sampled every set unit time, and the sampled value is a predetermined number. The process of obtaining the moving average value (51 pieces) is sequentially executed (steps 32 and 33). This moving average value is obtained every time the encoder 5 outputs a timing pulse.
[0035]
Further, the control unit H continuously executes the process of integrating the timing pulses output from the encoder 5, and when the reference signal output every rotation is input, the integrated value of the timing pulses at that time Is reset to zero, and such processing is repeatedly executed. Then, a process of obtaining the rotational phase of the crankshaft 4 when the moving average value becomes maximum in one cycle as the first preliminary compression top dead center TDC (Y1) is executed (step 34). Thus, steps 31 to 34 are repeatedly executed until the first preliminary compression top dead center TDC (Y1) is obtained.
[0036]
When the first pre-compression top dead center TDC (Y1) is obtained, the crankshaft 4 is then rotated in the reverse direction by the external driving means 3 so that the rotational speed (60 rpm) is 60 revolutions per minute. In the rotation state in the reverse rotation direction, the pressure detection value is sampled and the sampled value is moved by a predetermined number (51) in the same manner as the processing in the normal rotation state. The processing for obtaining the value is sequentially executed (steps 35, 36, 37, 38), and the rotational phase of the crankshaft 4 when the moving average value becomes maximum in one cycle is determined as the second preliminary compression top dead center TDC ( Y2) is obtained (step 39). Then, Steps 36 to 39 are repeatedly executed until the second preliminary compression top dead center TDC (Y2) is obtained.
When the second preliminary compression top dead center TDC (Y2) is obtained, the rotation operation of the electric motor 2 is stopped, and the second preliminary compression top dead center is positioned at the center between the first preliminary compression top dead center and the second preliminary compression top dead center. The rotational phase of the crankshaft 4 is determined as the compression top dead center of the engine (steps 40, 41, 42).
[0037]
In other words, FIG. 8 shows the output value of the encoder 5 and the detected pressure value (moving average value) in a state corresponding to the rotational phase of the crankshaft 4. Of these, FIG. 8A shows changes in the rotational state in the forward direction, and FIG. 8B shows changes in the rotational state in the reverse direction.
In a 4-cycle engine, the piston 7 reciprocates twice during the intake stroke, compression stroke, expansion stroke, and exhaust stroke, so there are two top dead centers of the compression stroke and the exhaust stroke. In the exhaust stroke, since the exhaust valve 10 is in the open state, the pressure in the cylinder does not become high, so the maximum pressure in the cylinder is the top dead center in the compression stroke (compression top dead center). Therefore, as shown in the figure, there is a point (compression top dead center) where the pressure in the cylinder once becomes high while the crankshaft 4 rotates twice.
Therefore, the angle information (A) between the point where the pressure in the forward rotation state becomes maximum (first preliminary compression top dead center) and the reference signal on the upper side in the rotational direction, and in the reverse rotation state The angle information (B) between the point at which the pressure becomes maximum (second preliminary compression top dead center) and the reference signal on the lower side in the rotational direction is obtained, and is shown in FIG. Thus, the phase that is the average value of the angle information (A) and the angle information (B) with the normal rotation state as a reference, that is, the center between the first preliminary compression top dead center and the second preliminary compression top dead center The rotational phase of the crankshaft 4 positioned at is determined as the true compression top dead center. The compression top dead center obtained in this way is stored in correspondence with the rotational phase obtained from the detection signal of the encoder 5.
Thereafter, the operation timing of the intake valve 9 and the exhaust valve 10 is detected based on the compression top dead center thus obtained.
Accordingly, the calculation means 100 for obtaining the compression top dead center of the test target engine 1 is configured using the control unit H.
[0038]
In addition, when the control unit H executes the process of detecting the opening timing of the exhaust valve 10, the detection information of the pressure sensor 15 in a state where the crankshaft 4 is rotated by the external drive means 3, and Based on the detection information of the encoder 5, the rotational phase at which the pressure in the cylinder changes from a decreasing tendency to an increasing tendency is detected as the opening timing of the exhaust valve 10.
[0039]
In other words, ascending state determination processing for determining whether or not the amount of change per unit time after the pressure in the cylinder detected by the pressure sensor 15 has changed from a decreasing tendency to an increasing tendency has exceeded a set value. And when the amount of change in internal pressure per unit time is determined to be greater than or equal to the set value in the rising state determination process, the rotation direction is set by the set amount from the rotation phase when the amount of change reaches the set value A phase calculation process for obtaining the rotation phase on the upper side as the rotation phase that changes from the decreasing tendency to the increasing tendency is executed.
[0040]
Next, the opening timing detection process of the exhaust valve 10 by the control unit H will be described. The exhaust valve opening timing detection process is performed separately for each cylinder. And when performing the detection process with respect to the reference | standard cylinder 6a, as shown to FIG. 9 (B), the flow-path switching valve 18 will be switched so that the pressure sensor 15 provided with the non-return valve 19 may act beforehand. .
FIG. 7 shows a flowchart of the opening timing detection processing of the exhaust valve 10 for the reference cylinder 6a (# 1), which will be specifically described based on the flowchart shown in FIG.
The external drive means 3 rotates the crankshaft 4 in the forward rotation direction, and based on the information detected by the encoder 5, the speed control is performed so that the rotational speed of the crankshaft 4 is 30 rpm per minute (30 rpm). (Step 51). In a state of rotating in the forward direction at such a set speed, the pressure detection value in the pressure sensor 15 is sampled every set unit time, and the sampled value is calculated by a predetermined number (51) of moving average values. The required processing is sequentially executed (steps 52 and 53). This moving average value is obtained every time the encoder 5 outputs a timing pulse.
[0041]
And the process which calculates | requires the raise variation | change_quantity per unit time of the calculated | required moving average value is performed (step 54), and after the moving average value changes from a decreasing tendency to an increasing tendency, the increasing change amount per unit time is set value. It is determined whether or not the above has been reached (step 55). This process corresponds to the rising state determination process. Steps 51 to 54 are repeatedly executed until it is determined that the amount of increase in change per unit time is equal to or greater than the set value. Then, when it is determined that the amount of increase in change per unit time is equal to or greater than the set value, the rotation phase on the upper side in the rotational direction by the set amount from the rotation phase when the amount of increase in change reaches the set value is A phase calculation process for obtaining a rotation phase that changes from a decreasing tendency to an increasing tendency is executed (step 56).
In this way, the rotational phase at which the pressure detection value in the pressure sensor 21 changes from a decreasing tendency to an increasing tendency is detected as the opening timing of the exhaust valve 10 based on the compression top dead center detected in the TDC detection process. To do.
[0042]
As described above, the opening timing detection process of the exhaust valve 10 is performed separately for the other cylinders 6 (# 2 to # 4).
Therefore, the timing detection means 101 for detecting the opening timing of the exhaust valve 10 is configured using the control unit H.
[0043]
In other words, FIG. 10 is provided corresponding to each cylinder when the crankshaft 4 is rotated in the forward rotation direction by the external driving means 3 with reference to the rotational phase information of the crankshaft 4. A change in the pressure detection value of the pressure sensor 15 is shown in association with the operation timing of the intake valve 9 and the exhaust valve 10. Incidentally, in FIG. 10, # 1 indicates the reference cylinder 6a, # 2 indicates the second cylinder 6, # 3 indicates the third cylinder 6, and # 4 indicates the fourth cylinder 6, “EX” indicates a state where the exhaust valve 10 in each cylinder 6 is open, and “IN” indicates a state where the intake valve 9 in each cylinder 6 is open.
[0044]
As is clear from this drawing, the intake valve 9 and the exhaust valve 10 are in the upper part of the rotational direction with respect to the timing at which the exhaust valve 10 opens, that is, in the expansion process in which the piston 7 descends from the compression top dead center. Since the piston 7 is lowered with the check valve 19 preventing the inflow of air from the outside, the inside of the cylinder becomes lower than the atmospheric pressure, and the lowering amount of the piston 7 is reduced. The larger the value, the lower the pressure. When the exhaust valve 10 is opened, air begins to flow into the cylinder from the outside, and the pressure inside the cylinder increases during the exhaust stroke, so the pressure inside the cylinder tends to increase from a decreasing trend. The changing rotational phase can be detected as the opening timing of the exhaust valve 10. In the intake stroke, the intake valve 9 is open, so that the inside of the cylinder is almost equal to the atmospheric pressure, and in the compression stroke, the compressed air in the cylinder flows out from the check valve 19 to the outside. Equal state.
[0045]
FIG. 11 is an enlarged view showing a change in the detected pressure value in a predetermined region Q including the timing at which the exhaust valve 10 in FIG. 10 opens. As is apparent from this figure, the exhaust valve 10 The pressure detection value changes from a decreasing trend to an increasing trend at the time when the valve is assumed to open, but the change is gradual, and as the moving average value of the pressure detection value is obtained sequentially, Thus, since it is difficult to detect the opening timing in real time from the information, the rotational phase on the upper side in the rotational direction by the set amount C from the rotational phase X1 when the amount of change to the ascending side per unit time reaches the set value. X2 is obtained as the rotational phase that changes from the decreasing tendency to the increasing tendency.
[0046]
[Another embodiment]
Hereinafter, other embodiments are listed.
[0047]
(1) In the above embodiment, the pressure detection value is sampled for each set period, and the moving average value for each set number of the sampled sampling values is obtained. However, instead of such processing, detection is performed. Various configurations such as processing that removes special data that changes locally such that the rate of change of the value is equal to or greater than the set value, and a configuration that inputs to the control unit through a low-pass filter that removes high-frequency components It can be implemented in the form.
[0048]
(2) In the above-described embodiment, as the configuration for obtaining the compression top dead center (TDC) as a reference for detecting the opening timing of the exhaust valve in the test target engine, the engine is operated in each of the normal rotation direction and the reverse rotation direction. The configuration in which the control unit obtains the compression top dead center by calculation based on the detection value of the pressure sensor that detects the pressure in the cylinder and the detection information of the encoder as the rotation phase detection means when rotating is illustrated. The present invention is not limited to such a configuration, and may be a configuration for detecting the compression top dead center from information on the rotational phase of the camshaft, control information for the fuel injection nozzle, and the like, and may be implemented in various forms.
[0049]
(3) In the above embodiment, the diesel engine is exemplified as the test target engine, and the pressure sensor 15 as the pressure detection means is connected using the mounting hole 13 for mounting the fuel injection nozzle. The test target engine is not limited to a diesel engine, and may be a gasoline engine. In that case, the pressure detection means may be connected using a mounting hole for mounting a spark plug.
[0050]
(4) In the above-described embodiment, the test is performed in a state where the test target engine is transported to a predetermined test setting position by the transport device and fixed in position, but instead of such a configuration, for example, transport You may apply to the engine test apparatus which tests an engine, moving in the state synchronized with the conveyance conveyor with respect to the engine to be conveyed in the state in which the engine to be tested is conveyed by the conveyor etc. Further, the connection work between the crankshaft and the external drive means, the connection work of various sensors, and the like may be automatically performed using an automatic connection device instead of the manual work.
[0051]
(5) In the above embodiment, the pressure detecting means is configured to be connected to the cylinder via a buffer for reducing pressure. However, pressure detection is not performed via such a buffer. It is good also as a structure which detects a pressure by connecting a means to a cylinder.
[0052]
(6) In the above embodiment, the hose as the pressure reducing buffer is exemplified by the pressure detecting means and the one-way flow forming means being provided in a parallel state. The means and the unidirectional flow forming means may be separately connected to the cylinder.
[0053]
(7) In the above embodiment, the external drive means rotates the crankshaft by rotating the electric motor, but various drive means such as a hydraulic motor can be applied.
[0054]
(8) In the above embodiment, a four-cylinder engine is exemplified as the test target engine. However, the number of cylinders of the engine to be tested can be appropriately changed, and the engine to be tested The number of intake valves and exhaust valves can be changed as appropriate, and various engines can be applied as test target engines.
[0055]
(9) In the above embodiment, an example in which the exhaust valve opening timing detection device in the engine to be tested according to the present invention is applied to the engine test device has been described. It is also possible to adapt to various devices related to engine testing.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an engine test apparatus.
FIG. 2 is a schematic diagram of an engine to be tested.
FIG. 3 is a diagram showing a connection state of a pressure sensor
FIG. 4 is a diagram showing a connection state of a pressure sensor
FIG. 5 is a flowchart of the control operation.
FIG. 6 is a flowchart of the control operation.
FIG. 7 is a flowchart of the control operation.
FIG. 8 is a timing chart in compression top dead center detection.
FIG. 9 is a diagram showing a flow path switching state.
FIG. 10 is a graph showing the relationship between engine operating conditions and pressure fluctuations.
11 is an enlarged view of a part of FIG.
[Explanation of symbols]
1 Test engine
3 External drive means
4 Crankshaft
5 Rotation phase detection means
6 cylinders
9 Intake valve
10 Exhaust valve
15 Pressure detection means
17 Buffer for decompression
19 Unidirectional flow forming means
101 Timing detection means

Claims (5)

An external drive means for forcibly rotating the crankshaft connected to the crankshaft in the engine under test assembled so that the intake valve and the exhaust valve are opened and closed with the rotation of the crankshaft;
Rotational phase detection means for detecting the rotational phase of the crankshaft;
Pressure detecting means for detecting the pressure in the cylinder of the test target engine;
A one-way flow forming means connected to the cylinder of the engine under test to allow the outflow of air from the inside of the cylinder and to prevent the inflow of air from the outside into the cylinder;
Based on the detection information of the pressure detection means and the detection information of the rotation phase detection means in a state where the crankshaft is rotated by the external drive means, the pressure in the cylinder tends to increase from a decreasing tendency An exhaust valve opening timing detection device in a test target engine, comprising: a timing detection unit that detects a rotation phase that changes to an opening timing of the exhaust valve. The timing detection means;
Ascending state determination processing for determining whether or not the amount of change per unit time after the pressure in the cylinder has changed from a decreasing tendency to an increasing tendency has become a set value;
When it is determined that the amount of change per unit time of the pressure has reached the set value in the rising state determination process, the amount of change on the upper side in the rotational direction is increased by the set amount from the rotation phase when the amount of change reaches the set value. The exhaust valve opening timing detection device for an engine to be tested according to claim 1, wherein a phase calculation process for obtaining a rotation phase as a rotation phase that changes from a decreasing tendency to an increasing tendency is executed. The timing detection means;
The pressure detection value detected by the pressure detection means is sampled at each set cycle, and a moving average value for each set number of the sampled sampling values is obtained, and the moving average value changes from a decreasing tendency to an increasing tendency. The exhaust valve opening timing detection device for an engine under test according to claim 1 or 2, wherein the rotation phase to be detected is detected as an opening timing of the exhaust valve. The test target engine according to any one of claims 1 to 3, wherein the pressure detection means is configured to be connected to a cylinder of the test target engine via a buffer for reducing pressure. Exhaust valve opening timing detection device. The said buffer part for pressure reduction is a hose connected to the cylinder of the said test object engine, The said pressure detection means and the said one-way flow formation means are equipped with this hose in parallel. Exhaust valve opening timing detection device for the engine under test.

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