JP2022119658A - Internal combustion engine inspection method and internal combustion engine inspection apparatus - Google Patents

Abstract

To provide an internal combustion engine inspection method and an internal combustion engine inspection apparatus, at low costs and with sufficiently secured function and performance of the internal combustion engine.SOLUTION: An internal combustion engine inspection method inspects whether an internal combustion engine 1 is normal by using an internal combustion engine inspection apparatus 100. The inspection method includes: an introduction step of introducing, into an intake channel 11 of the internal combustion engine 1, air compressed by a pressurizing mechanism 2 of the inspection apparatus 100 to pressure with which in-cylinder pressure of the internal combustion engine 1 in a combustion stroke can be reproduced; and a motoring step of motoring the internal combustion engine 1. The inspection method further included a determination step of detecting, during or after the motoring, a value of a parameter enabling determination as to whether the engine 1 is normal, and determining whether the internal combustion engine 1 is normal on the basis of the detected value of the parameter.SELECTED DRAWING: Figure 1

Description

The present invention relates to an internal combustion engine inspection method and an internal combustion engine inspection apparatus.

2. Description of the Related Art When inspecting an internal combustion engine by burning the engine, facilities for handling fuel, air conditioning, and exhaust treatment are required. Also, it takes time to connect the internal combustion engine to these facilities. For this reason, there is a problem that the cost is extremely high in order to perform a 100% inspection by burning internal combustion engines in mass production.

On the other hand, Patent Literature 1 discloses an inspection method of an engine (internal combustion engine) in which vibration is measured by motoring the engine (internal combustion engine) without burning the engine (internal combustion engine).

Patent No. 4073899

In order to fully guarantee the function and performance of the internal combustion engine, it is preferable to inspect the combustion chamber pressure of the internal combustion engine in the vicinity of the design upper limit, ie, reproduce the combustion pressure of the internal combustion engine. In the method for inspecting an internal combustion engine disclosed in Patent Document 1, atmospheric pressure air is introduced into the combustion chamber and the internal combustion engine is inspected by motoring. Therefore, although the pressure in the combustion chamber rises during the compression stroke, it is not possible to reproduce the high pressure at the time of combustion. In other words, the inspection method described in the above literature cannot reproduce the combustion pressure during operation of the internal combustion engine in a real environment. Therefore, the method for inspecting an internal combustion engine described in Patent Document 1 may not be able to sufficiently guarantee the function and performance of the internal combustion engine.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an internal combustion engine inspection method and an internal combustion engine inspection apparatus that are low in cost and sufficiently ensure the functions and performance of the internal combustion engine.

According to one aspect of the present invention, there is provided an internal combustion engine inspection method for inspecting whether an internal combustion engine is normal using an internal combustion engine inspection apparatus. This inspection method includes an introduction step of introducing gas pressurized to a pressure that can reproduce the cylinder internal pressure in the combustion process of the internal combustion engine by the pressurization mechanism of the inspection device into the intake passage of the internal combustion engine, and a motor for motoring the internal combustion engine. and a ring step. During or after motoring, the value of a parameter capable of determining whether or not the internal combustion engine is normal is detected, and determination is made based on the detected parameter value as to whether or not the internal combustion engine is normal. Including process.

According to the present invention, gas pressurized to a pressure that can reproduce the in-cylinder pressure in the combustion process of the internal combustion engine is sucked into the combustion chamber. It is possible to reproduce and inspect internal combustion engines. That is, it is possible to provide an inspection method for an internal combustion engine that is low in cost and that sufficiently guarantees the function and performance of the internal combustion engine.

FIG. 1 is a schematic configuration diagram of an internal combustion engine inspection apparatus according to an embodiment of the present invention. FIG. 2 is a timing chart showing the relationship between the internal combustion engine cycle and the in-cylinder pressure in normal combustion, the present embodiment, and the comparative example. FIG. 3 is a timing chart showing the relationship between the internal combustion engine cycle and the in-cylinder pressure in the internal combustion engine inspection method according to the embodiment of the present invention. FIG. 4 is a flow chart illustrating an internal combustion engine inspection method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like.

FIG. 1 is a schematic configuration diagram of an internal combustion engine inspection apparatus 100 according to an embodiment of the present invention.

An inspection device 100 for an internal combustion engine is configured by installing an internal combustion engine 1 to be inspected in an inspection device main body. The main body of the inspection apparatus is composed of a compressor (pressurizing mechanism) 2, a constant pressure valve 3, a circulation passage 4, a surge tank 5, a vibration sensor (state detection sensor) 6, a controller 7, and the like. A motor for motoring (not shown) is also connected to the internal combustion engine 1 . Although only one cylinder is shown in FIG. 1, the present embodiment can also be applied to a multi-cylinder internal combustion engine.

The internal combustion engine 1 is, for example, an internal combustion engine for a vehicle such as an automobile, and has an intake passage 11 and an exhaust passage 12 . The intake passage 11 and the exhaust passage 12 are connected via the recirculation passage 4 of the inspection device 100 .

The internal combustion engine 1 is, for example, an in-cylinder direct injection spark ignition internal combustion engine having a cylinder 13. A piston 14 reciprocating in the cylinder 13 and a variable compression ratio mechanism (VCR) for driving the piston 14 are provided in the cylinder block 13A. ) 15.

The internal combustion engine 1 also has a combustion chamber 16 inside the cylinder 13 . The combustion chamber 16 is configured in a so-called pent roof type, and an intake valve 111 and an exhaust valve 121 are arranged on an inclined surface on the intake side and an inclined surface on the exhaust side, respectively. A spark plug 17 is arranged along the axis of the cylinder 13 at a substantially central position of the combustion chamber 16 surrounded by the intake valve 111 and the exhaust valve 121 .

The variable compression ratio mechanism (VCR) 15 is a mechanism known by the applicant and utilizing a multi-link piston crank mechanism. The variable compression ratio mechanism 15 has a link mechanism 15A including a plurality of links 152 and 153 provided between the piston 14 and the crankshaft 151, and regulates (adjusts) the posture of the link mechanism 15A to change the compression ratio. and a compression ratio control mechanism 15B. The link mechanism 15A includes an upper link 152 and a lower link 153, and the compression ratio control mechanism 15B includes a control link 154 and a control shaft 155. The lower link 153 is rotatably fixed to the crankpin 151A of the crankshaft 151 and connected to the piston 14 via the upper link 152 . Also, the lower link 153 is connected to a control shaft 155 via a control link 154 . The control link 154 is connected to a position offset from the rotation axis of the control shaft 155 . The control shaft 155 is rotationally driven by an electric motor 156 via, for example, a rack and pinion mechanism. The electric motor 156 is configured so as to be controllable by the controller 7 of the inspection apparatus 100 .

With the above configuration, when the control shaft 155 rotates and the control link 154 is pulled down, the lower link 153 rotates about the crank pin 151A, and the upper link 152 is pushed up. As a result, the top dead center position of the piston 14 rises. Conversely, when the control link 154 is pushed up, the upper link 152 is pulled down and the top dead center position of the piston 14 is lowered. Thus, the variable compression ratio mechanism 15 can change the so-called mechanical compression ratio by changing the top dead center position of the piston 14 .

The cylinder 13 of the internal combustion engine 1 is provided with an in-cylinder pressure sensor (not shown) for detecting the in-cylinder pressure. Information on the in-cylinder pressure detected by the in-cylinder pressure sensor is transmitted to the controller 7 .

The intake passage 11 is a passage through which gas flowing into the combustion chamber 16 flows, and is connected to the combustion chamber 16 via an intake valve 111 . The exhaust passage 12 is a passage through which exhaust from the combustion chamber 16 flows, and is connected to the combustion chamber 16 via an exhaust valve 121 . The intake passage 11 and the exhaust passage 12 are connected via a recirculation passage 4 . That is, the intake passage 11 and the exhaust passage 12 are configured so that the gas exhausted to the exhaust passage 12 is recirculated to the intake passage 11 via the recirculation passage 4 .

The compressor 2 is a pressurizing mechanism provided outside the internal combustion engine 1 , pressurizes outside air, and supplies the pressurized air to the intake passage 11 through the recirculation passage 4 . Note that the compressor 2 is controlled by a controller 7 .

The constant pressure valve 3 is, for example, a relief valve, and is provided inside the surge tank 5 between the compressor 2 and the recirculation passage 4 . The constant pressure valve 3 is opened when the pressure of the air supplied from the compressor 2 to the intake passage 11 through the recirculation passage 4 falls below a certain level. As a result, the pressure of the air in the intake passage 11 is maintained at a predetermined pressure.

The recirculation passage 4 is a passage that connects the intake passage 11 and the exhaust passage 12 . The gas exhausted to the exhaust passage 12 is led to the intake passage 11 by the recirculation passage 4 .

A surge tank 5 for suppressing air pulsation due to a pressure difference is provided in the return passage 4 .

A pressure sensor (not shown) is provided in each of the passages (intake passage 11, exhaust passage 12, recirculation passage 4) to detect the gas pressure in the passage. Pressure information detected by the pressure sensor is transmitted to the controller 7 .

A vibration sensor (state detection sensor) 6 is installed on the outer wall side surface of the cylinder block 13A of the cylinder 13 and detects vibration of the main body of the internal combustion engine 1 . As will be described later, when the internal combustion engine 1 is inspected, the vibration sensor 6 detects vibration due to the stroke operation of the internal combustion engine 1 when the motoring is started. Vibration information detected by the vibration sensor 6 is transmitted to the controller 7 .

The controller 7 is composed of a computer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM) and an input/output interface (I/O interface), and integrates the internal combustion engine inspection device 100. control. It is also possible to configure the controller 7 with a plurality of microcomputers. The controller 7 performs, for example, drive control of the compressor 2, motoring motor and electric motor 156, determination of normality or abnormality of the variable compression ratio mechanism 15 based on vibration information from the vibration sensor 6, and the like. The controller 7 also executes a process for controlling the internal combustion engine inspection device 100 by executing a specific program.

The internal combustion engine inspection apparatus 100 configured as described above performs so-called motoring, in which a motor for motoring is driven to operate the variable compression ratio mechanism 15 in a stroke, and vibrations of the internal combustion engine 1 during stroke operation are detected. Detected by the vibration sensor 6 . Then, based on the detected vibration information, it is determined whether or not the operating state of the variable compression ratio mechanism 15 is normal.

By the way, in order to fully guarantee the function and performance of the internal combustion engine, it is preferable to inspect the internal combustion engine with the combustion chamber pressure near the design upper limit. In particular, when the combustion chamber pressure is close to the design upper limit, the variable compression ratio mechanism (VCR) is designed carefully to prevent seizure, etc., because the compression ratio control mechanism such as the control link is easily loaded. In addition to quality control, it is preferable to conduct inspections just in case. In this case, it is desirable to reproduce the combustion pressure of the internal combustion engine for inspection. However, in order to actually use the fuel to perform stroke operation and inspect the internal combustion engine, additional equipment such as equipment for handling the fuel, air conditioning, and exhaust treatment is required. Also, it takes time to connect the internal combustion engine to these facilities. For this reason, in mass production, if a combustion process is performed and all internal combustion engines are inspected, the cost becomes enormous. On the other hand, when the internal combustion engine is motored and inspected, even if the air in the combustion chamber is adiabatically compressed to increase the pressure in the combustion chamber, the high pressure at the time of combustion cannot be reproduced.

Therefore, in the present embodiment, the outside air is pressurized by a compressor (pressurizing mechanism) 2 outside the internal combustion engine 1 to a pressure that can reproduce the cylinder internal pressure in the combustion process of the internal combustion engine 1, and the pressurized air is supplied to the intake passage 11. decided to introduce it. As a result, the pressurized air is sucked into the combustion chamber 16 of the internal combustion engine 1 by the motoring, and when the piston 14 rises and is compressed, the pressure in the combustion chamber 16 is equivalent to the combustion pressure of the internal combustion engine 1. rises to In this way, the air pressurized to a pressure that can reproduce the cylinder internal pressure in the combustion stroke of the internal combustion engine 1 is sucked into the combustion chamber 16. The internal combustion engine 1 can be inspected by reproduction.

FIG. 2 is a timing chart showing the relationship between the cycle of the internal combustion engine 1 and the in-cylinder pressure. FIG. 2 compares the in-cylinder pressure when combustion is performed in the internal combustion engine 1 (normal combustion) and the in-cylinder pressure during motoring (this embodiment) in the inspection method of this embodiment. In FIG. 2, t ₁ to t ₂ are intake strokes, t ₂ to t ₃ are compression strokes, t ₃ to t ₄ are expansion strokes, and t ₄ to t ₅ are exhaust strokes. Also, t1 is the _top dead center timing in the intake stroke, t2 is the _bottom dead center timing in the intake stroke (compression stroke) _, t3 is the top dead center timing in the compression stroke ₍ expansion stroke), and t4 is the expansion stroke. This is the timing of the bottom dead center in the stroke. Although gas does not expand due to combustion during motoring _, the period from timing t3 at top dead center to timing _t4 at bottom dead center in the compression stroke is called an expansion stroke for convenience.

As shown in FIG. 2, in normal combustion, the intake valve 111 is opened at t ₁ , and when the piston 14 descends, air at atmospheric pressure Pa is drawn into the combustion chamber 16 . Therefore, the in-cylinder pressure also becomes the atmospheric pressure Pa. On the other hand, in the present embodiment, air compressed by the compressor 2 is taken in, so the cylinder internal pressure becomes P ₁ higher than the atmospheric pressure Pa. Here, P ₁ is a pressure such that the cylinder internal pressure becomes equal to the maximum value P _max of the cylinder internal pressure in normal combustion at the top dead center timing t ₃ in the later-described compression stroke (expansion stroke). The compressor 2 pressurizes outside air so that the pressure of the air taken into the combustion chamber 16 becomes P ₁ and supplies the outside air to the intake passage 11 .

At t2, which is the timing of the _bottom dead center, the intake valve 111 is closed, and in the compression stroke, as the piston 14 rises, the air in the combustion chamber 16 is compressed, and the cylinder pressure gradually increases. go. In normal combustion, fuel is injected during the compression stroke and combustion begins with spark ignition at t ₂ '. As a result, the in-cylinder pressure rises at once and reaches the maximum value P _max at t ₃ '. On the other hand, in the present embodiment, in which air pressurized by the compressor ₂ is taken in, the cylinder internal pressure at t2 at the start of the compression stroke is the pressure P1 that is higher than the atmospheric pressure Pa _, so the _top dead center timing t3 is reached. , the in-cylinder pressure reaches a pressure equivalent to the maximum value _Pmax in normal combustion. On the other hand, when air of atmospheric pressure Pa is introduced into the internal combustion engine ₁ and motoring is performed, the cylinder internal pressure at t2 at the start of the compression stroke is atmospheric pressure Pa _, so the top dead center timing t3 in the compression stroke is , the in-cylinder pressure rises only up to P2, which is smaller _{than Pmax} . In normal combustion, the in-cylinder pressure reaches the maximum value P _max at t ₃ ′ _, which is slightly later than t ₃ which is the timing of top dead center. The maximum value P _max is reached at .

During the expansion stroke from t ₃ to t ₄ , as the piston 14 descends and the air in the combustion chamber 16 expands, the cylinder internal pressure gradually decreases. As described above, in normal combustion, the in-cylinder pressure reaches the maximum value P _max at t ₃ ', which is slightly later than t ₃ , so the in-cylinder pressure decreases from t ₃ ' to t ₄ .

At t4, which is the timing of the bottom dead center, the in _{- cylinder} pressure becomes P3 in both normal combustion and the present embodiment. Here, the cylinder internal pressure P ₃ is higher than the atmospheric pressure Pa, but since gas leaks (blow-by) from the gap between the piston and the cylinder wall (piston-bore), when air is drawn into the combustion chamber 16 in this embodiment, is smaller than the pressure P ₁ of .

When the exhaust valve 121 is opened at t4, the in- _cylinder pressure becomes the atmospheric pressure Pa in normal combustion. On the other hand, in the present embodiment, the exhaust gas from the combustion chamber 16 having a higher pressure than the atmospheric pressure Pa is recirculated from the exhaust passage 12 to the intake passage 11 via the recirculation passage 4 . Therefore, even in the exhaust stroke in which the exhaust valve 121 is open, the in _- cylinder pressure is maintained at P3, which is higher than the atmospheric pressure Pa. Further, as will be described later, in the present embodiment, the air pressurized by the compressor ₂ and the recirculated air (exhaust) are injected into the intake passage 11 so that the cylinder internal pressure becomes P1 at the start of the intake stroke of the next cycle. introduced into

As described above, in the present embodiment, since the air compressed by the compressor 2 is drawn into the combustion chamber 16, it is possible to reproduce an in-cylinder pressure equivalent to the maximum value _Pmax of the in-cylinder pressure in normal combustion.

FIG. 3 is a timing chart showing the relationship between the cycle of the internal combustion engine 1 and the in-cylinder pressure in the internal combustion engine inspection method according to the embodiment of the present invention. FIG. 3 shows the in-cylinder pressure of the internal combustion engine 1 at the (n−1)th cycle and the nth cycle. In FIG. 3, t ₁ to t ₂ , t ₂ to t ₃ , t ₂ to t ₃ , and t ₃ to t ₄ are respectively the intake stroke (t ₁ to t ₂ ) and the compression stroke (t ₂ to t ₃ ), an expansion stroke (t ₃ to t ₄ ), and an exhaust stroke (t ₄ to t ₅ ). Further, t ₅ to t ₆ , t ₆ to t ₇ , t ₇ to t ₈ and t ₈ to t ₉ are respectively the intake stroke (t ₅ to t ₆ ) and the compression stroke (t ₆ to t ₇ ), an expansion stroke (t ₇ to t ₈ ), and an exhaust stroke (t ₈ to t ₉ ). Further, t1, t3 _{, t5} , _t7 and _t9 are top dead center _timings , and _t2 , _t4 , _t6 and _t8 are bottom dead center timings.

The intake stroke (t ₁ to t ₂ ), compression stroke (t ₂ to t ₃ ), and expansion stroke (t ₃ to t ₄ ) of the (n−1)th cycle are the same as in FIG. .

As described above, during the expansion stroke from t3 to t4 _, gas leaks (blow _- by) from the gap between the piston 14 and the cylinder wall (piston-bore), so the cylinder pressure drops to P3 _, which is lower _than P1. do.

When the exhaust valve 121 is opened at t ₄ , the gas (air) in the combustion chamber 16 is exhausted to the exhaust passage 12 during the exhaust stroke from t ₄ to t ₅ . Since the exhaust passage 12 is connected to the intake passage 11 , the air exhausted to the exhaust passage 12 is recirculated to the intake passage 11 . Therefore, in the present embodiment, the in-cylinder pressure does not decrease to the atmospheric pressure Pa in the exhaust stroke, and the in _- cylinder pressure P3 at the start of the exhaust stroke is maintained.

During the exhaust stroke (t ₄ to t ₅ ), outside air pressurized by the compressor 2 is supplied to the intake passage 11 through the constant pressure valve 3 . That is, the air pressurized by the compressor 2 is introduced into the intake passage 11 together with the air (exhaust) recirculated from the exhaust passage 12 .

Here, the constant pressure valve 3 is opened when the pressure of the air supplied to the intake passage 11 from the compressor 2 falls below a certain level, so that the pressure of the gas introduced into the intake passage 11 is maintained at a predetermined pressure. is configured to That is, the constant pressure valve 3 maintains the pressure of the mixture of the recirculated gas introduced into the intake passage 11 and the gas supplied from the compressor 2 at a predetermined pressure. Here, the predetermined pressure is a pressure that can reproduce the in-cylinder pressure during combustion of the internal combustion engine 1 .

In this manner, during the exhaust stroke, the air pressurized by the compressor 2 is introduced into the intake passage 11 together with the recirculated air. Then, the constant pressure valve 3 introduces the air introduced from the compressor 2 into the intake passage 11 so that the pressure of the gas introduced into the intake passage 11 becomes a pressure that can reproduce the in-cylinder pressure during combustion of the internal combustion engine 1. quantity is adjusted. Therefore, the in-cylinder pressure in the intake stroke of the next cycle (nth cycle) of the internal combustion engine 1 reaches a pressure equivalent to the combustion pressure of the internal combustion engine 1 at timing _t7 of the top dead center of the compression stroke (expansion stroke). pressure P ₁ . In other words, during the exhaust stroke, air pressurized from the compressor 2 is introduced into the intake passage 11 to compensate for the pressure that has decreased due to gas leak (blow-by). Therefore, the in-cylinder pressure in the n-1th cycle intake stroke (t ₁ to t ₂ ) becomes equal to the in-cylinder pressure in the nth cycle intake stroke (t ₅ to t ₆ ).

Since the exhaust pressure in the exhaust stroke is lowered due to gas leak (blow-by), when the pressurized air is introduced into the intake passage 11, the passage (intake passage 11, exhaust passage 12, recirculation passage 4) There is a risk that a pressure difference will be generated inside and pulsation will occur. In addition, air is sucked into the combustion chamber 16 during the intake stroke, which may reduce the pressure in the intake passage 11 and cause pulsation. If this pulsation is not absorbed, the in-cylinder pressure in the intake stroke may fall short of the assumed pressure P ₁ due to resonance or the like. In contrast, in the present embodiment, the exhaust passage 12 and the intake passage 11 are connected via the surge tank 5 provided in the recirculation passage 4, so the surge tank 5 absorbs the pulsation in the passage. Further, when the internal combustion engine 1 has a plurality of cylinders, the surge tank 5 also removes pulsation between the cylinders. Therefore, the decrease in pressure during the intake stroke is suppressed.

As described above, the in-cylinder pressure in the n-th cycle intake stroke (t ₅ -t ₆ ) becomes P ₁ equal to the in-cylinder pressure in the (n−1)-th cycle intake stroke (t ₁ -t ₂ ). Therefore, when the piston 14 rises in the n-th cycle compression stroke (t ₆ to t ₇ ), the cylinder pressure at the top dead center timing t ₇ is equivalent to the maximum value P _max of the cylinder pressure during combustion of the internal combustion engine 1. reaches a pressure of That is, the combustion pressure of the internal combustion engine 1 is reproduced at the timing _t7 of the top dead center.

As in the n-1th cycle, in the nth cycle as well, during the expansion stroke (t ₇ to t ₈ ), the in-cylinder pressure drops from P ₁ to P ₃ corresponding to the gas leak (blow-by). Also, during the exhaust stroke (t ₈ to t ₉ ), the air pressurized from the compressor 2 is introduced into the intake passage 11 to compensate for the gas leak (blow-by) pressure.

In this way, the internal combustion engine 1 reproduces the combustion pressure in each cycle during motoring. A vibration sensor 6 for detecting vibration of the main body of the internal combustion engine 1 detects vibration due to stroke operation of the internal combustion engine 1 during motoring. Anomalies can be predicted.

FIG. 4 is a flowchart for explaining the inspection method for the internal combustion engine 1 according to this embodiment. In this embodiment, the object of inspection is the compression ratio control mechanism 15B of the variable compression ratio mechanism 15 in the internal combustion engine 1, which is particularly susceptible to seizure or the like.

As shown in FIG. 4, the method for inspecting the internal combustion engine 1 according to the present embodiment comprises an introduction step (S101) for introducing outside air, a motoring step (S102), and whether or not the compression ratio control mechanism 15B to be inspected is normal. and a determination step (S103) for determining. The following processes in the introduction step (S101), the motoring step (S102), and the determination step (S103) are all executed simultaneously by the controller 7 continuously for a predetermined period of time.

When the internal combustion engine 1 is installed in the inspection device main body and the inspection device 100 for the internal combustion engine 1 is activated, the controller 7 starts inspection processing of the internal combustion engine 1 . During the inspection period, the controller 7 constantly receives information on the gas pressure in the passages (intake passage 11, exhaust passage 12, recirculation passage 4), cylinder internal pressure of the internal combustion engine 1, and vibration of the body of the internal combustion engine 1.

Step S101 is an introduction process for introducing outside air into the internal combustion engine 1 to be inspected. In the introduction step ( S<b>101 ), the controller 7 pressurizes outside air (air) to a predetermined pressure with the compressor 2 and introduces the pressurized air into the intake passage 11 through the recirculation passage 4 . Also, due to the action of the constant pressure valve 3 between the compressor 2 and the intake passage 11, the air in the intake passage 11 is maintained at a predetermined pressure. Here, the predetermined pressure is a pressure that makes the cylinder pressure of the internal combustion engine 1 equal to the cylinder pressure during combustion of the internal combustion engine 1 under the actual environment in the motoring step (S102). As described above, the introduction step (S101) continues for a predetermined period of time, and pressurized air is constantly fed into the intake passage 11 from the compressor 2 during the inspection period.

Step S102 is a motoring step for motoring the internal combustion engine 1 . In the motoring step ( S102 ), the controller 7 drives the motoring motor outside the internal combustion engine 1 to motor the internal combustion engine 1 . As described above, in the intake stroke of motoring, the air pressurized by the compressor 2 is sucked in, and at the timing of the top dead center in the compression stroke, the cylinder internal pressure reaches the maximum value _Pmax of the cylinder internal pressure during combustion of the internal combustion engine 1. pressure is equivalent to That is, the in-cylinder pressure at the time of combustion is reproduced.

Further, at the timing of the bottom dead center in the expansion stroke of the motoring, the in-cylinder pressure is lower than that during the intake stroke by the amount of gas leakage (blow-by). In the exhaust stroke of motoring, the air in the cylinder is exhausted to the exhaust passage 12 , and the exhausted air is returned from the exhaust passage 12 to the intake passage 11 via the surge tank 5 .

In a state where exhaust gas is recirculated, in the introduction step (S101), the air pressurized by the compressor 2 is introduced into the intake passage 11 together with the recirculated exhaust gas (air), and is lowered due to gas leak (blow-by). Compensates for pressure.

Step S103 is a determination process for determining whether or not the compression ratio control mechanism 15B to be inspected is normal. In the determination step (S103), the controller 7 determines whether or not the compression ratio control mechanism 15B is normal based on vibration information of the main body of the internal combustion engine 1 detected by the vibration sensor 6 during motoring. The correlation between the vibration of the main body of the internal combustion engine 1 and whether the compression ratio control mechanism 15B is normal or abnormal can be obtained in advance through experiments or the like. Therefore, from the vibration information of the main body of the internal combustion engine 1, it is possible to predict an abnormality such as seizure in the control link 154 of the compression ratio control mechanism 15B. It should be noted that the abnormality here is not limited to the case where an abnormality such as seizure actually occurs in the compression ratio control mechanism 15B, but it is predicted that an abnormality such as seizure will occur when motoring is continued. It also includes cases where there is a sign of anomaly occurrence.

In the determination step (S103), when an abnormality such as seizure of the compression ratio control mechanism 15B is predicted from the vibration information of the main body of the internal combustion engine 1, the controller 7 determines that there is an abnormality. When it is determined that there is an abnormality, the controller 7 notifies the operator or the like of the abnormality through a monitor or the like.

On the other hand, when the internal combustion engine 1 is predicted to be normal, the controller 7 continues the introduction step (S101), the motoring step (S102) and the determination step (S103).

The controller 7 performs the processing in the introduction step (S101), the motoring step (S102), and the determination step (S103) when a predetermined time has elapsed from the start of the inspection of the internal combustion engine 1, or when the inspection object (compression ratio This is continued until the control mechanism 15B) is determined to be abnormal. It should be noted that the predetermined time here is a time sufficient for an abnormality or a sign of abnormality to appear when the object to be inspected (compression ratio control mechanism 15B) is not normal, and can be set in advance by experiment or the like. can.

According to the method for inspecting the internal combustion engine 1 and the inspection apparatus 100 for the internal combustion engine of the embodiment described above, the following effects can be obtained.

According to the inspection method of the internal combustion engine 1, air (gas) pressurized by a compressor (pressurization mechanism) 2 to a pressure that can reproduce the cylinder internal pressure in the combustion process of the internal combustion engine 1 is introduced into the intake passage 11, and the internal combustion engine 1 is motored and pressurized air (gas) is sucked into the combustion chamber 16 of the internal combustion engine 1 . In this way, since the air (gas) pressurized to a pressure that can reproduce the cylinder internal pressure in the combustion stroke of the internal combustion engine 1 is sucked into the combustion chamber 16, even if the internal combustion engine 1 does not perform combustion, The internal combustion engine 1 can be inspected by reproducing the combustion pressure of . That is, it is possible to provide an inspection method for the internal combustion engine 1 that is low in cost and that sufficiently guarantees the functions and performance of the internal combustion engine 1 .

According to the inspection method of the internal combustion engine 1, the air (gas) exhausted to the exhaust passage 12 of the internal combustion engine 1 is recirculated to the intake passage 11 in the exhaust stroke of the motoring. As a result, it is possible to prevent the in-cylinder pressure of the internal combustion engine 1 from dropping to the atmospheric pressure Pa during the exhaust stroke. Therefore, if the pressure is increased by the amount of the pressure drop due to air (gas) leak (blow-by), the cylinder pressure equivalent to the cylinder pressure during the combustion stroke of the internal combustion engine 1 is reproduced by motoring even in the second and subsequent cycles of the internal combustion engine 1. can. That is, power consumption for pressurization can be suppressed, and a lower-cost inspection method for the internal combustion engine 1 can be provided.

According to the inspection method of the internal combustion engine 1, the pressure of the air (gas) introduced into the intake passage 11 reproduces the in-cylinder pressure in the combustion process of the internal combustion engine 1 by the constant pressure valve 3 between the compressor 2 and the intake passage 11. The amount of air (gas) introduced from the compressor (pressurizing mechanism) 2 is adjusted so that the pressure (predetermined pressure) is maintained. In this manner, the amount of air (gas) introduced from the compressor (pressurizing mechanism) 2 is adjusted so that the pressure of the air in the intake passage 11 is always at a predetermined pressure. In this case as well, the in-cylinder pressure equivalent to the in-cylinder pressure during combustion in the internal combustion engine 1 can be reproduced by motoring. In addition, in the second and subsequent cycles of the internal combustion engine 1, the pressure is increased by the pressure drop due to air (gas) leakage (blow-by), so power consumption for pressurization can be suppressed, and the internal combustion engine can be manufactured at a lower cost. 1 inspection method can be provided.

According to the inspection method of the internal combustion engine 1, it is determined whether or not the compression ratio control mechanism 15B is normal. In this way, since the compression ratio control mechanism 15B, which is particularly prone to seizure, is subject to inspection, the functions and performance of the internal combustion engine 1 can be sufficiently guaranteed by the inspection.

According to the inspection method of the internal combustion engine 1, the vibration sensor 6 detects the vibration of the main body of the internal combustion engine 1 during motoring, and it is determined whether the compression ratio control mechanism 15B is normal based on the detection information. Since it is determined whether or not the compression ratio control mechanism 15B is normal by detecting the vibration during motoring without performing combustion in the internal combustion engine 1, the internal combustion engine 1 can be inspected at low cost. .

According to the inspection device 100 for an internal combustion engine, a compressor (gas) introduced into the internal combustion engine 1 is pressurized to a pressure that can reproduce the cylinder internal pressure in the combustion process of the internal combustion engine 1 by motoring, and is supplied to the intake passage 11 ( pressure mechanism) 2. As a result, even if the internal combustion engine 1 does not perform combustion, the internal combustion engine 1 is motorized and pressurized air (gas) is sucked into the combustion chamber 16 to reproduce the combustion pressure of the internal combustion engine 1 in the compression stroke. can do. That is, the internal combustion engine 1 can be inspected by reproducing the combustion pressure of the internal combustion engine 1 by motoring. Therefore, it is possible to inspect the internal combustion engine 1 at a low cost and sufficiently guarantee the functions and performance of the internal combustion engine 1 .

According to the internal combustion engine inspection device 100, the intake passage 11 and the exhaust passage 12 of the internal combustion engine 1 are connected. As a result, the air (gas) exhausted to the exhaust passage 12 of the internal combustion engine 1 is recirculated to the intake passage 11 in the exhaust stroke of the motoring, so that the cylinder internal pressure of the internal combustion engine 1 decreases to the atmospheric pressure Pa in the exhaust stroke. can be prevented. Therefore, if the pressure is increased by the amount of the pressure drop due to air (gas) leak (blow-by), the cylinder pressure equivalent to the cylinder pressure during the combustion stroke of the internal combustion engine 1 is reproduced by motoring even in the second and subsequent cycles of the internal combustion engine 1. can. That is, power consumption for pressurization can be suppressed, and the internal combustion engine 1 can be inspected at a lower cost.

According to the internal combustion engine inspection device 100 , the constant pressure valve 3 is provided between the compressor (pressurizing mechanism) 2 and the intake passage 11 . Air (gas) from the compressor (pressurization mechanism) 2 is controlled by the constant pressure valve 3 so that the pressure of the air (gas) introduced from the compressor (pressurization mechanism) 2 into the intake passage 11 is maintained at a predetermined pressure. ) is adjusted. As a result, the pressure of the air (gas) in the intake passage 11 is always at a predetermined pressure, so that the cylinder pressure equal to the cylinder pressure in the combustion process of the internal combustion engine 1 is maintained by motoring in any number of cycles of the internal combustion engine 1. can be reproduced. In addition, in the second and subsequent cycles of the internal combustion engine 1, the pressure is increased by the pressure drop due to air (gas) leakage (blow-by), so power consumption for pressurization can be suppressed, and the internal combustion engine can be manufactured at a lower cost. 1 test can be performed.

According to the internal combustion engine inspection device 100 , the exhaust passage 12 and the intake passage 11 are connected via the surge tank 5 . This absorbs the pulsation caused by the pressure difference between the exhaust passage 12 and the intake passage 11 and the pulsation between the cylinders, thereby suppressing the pressure drop during the intake stroke. Therefore, it is possible to reproduce the cylinder pressure equivalent to the cylinder pressure in the combustion stroke of the internal combustion engine 1 by motoring, and the internal combustion engine 1 can be inspected at a low cost so that the functions and performance of the internal combustion engine 1 are sufficiently guaranteed. be able to.

According to the internal combustion engine inspection device 100 , the object of inspection is the compression ratio control mechanism 15</b>B of the variable compression ratio mechanism 15 . In this way, since the compression ratio control mechanism 15B, which is particularly prone to seizure, is subject to inspection, the functions and performance of the internal combustion engine 1 can be sufficiently guaranteed by the inspection.

According to the internal combustion engine inspection device 100 , the vibration sensor 6 is provided for detecting vibration of the main body of the internal combustion engine 1 . As a result, it is possible to detect vibration of the main body of the internal combustion engine 1 during motoring, and to determine whether or not the compression ratio control mechanism 15B is normal based on the detected information. Therefore, it is possible to determine whether the compression ratio control mechanism 15B is normal or not from the vibration during motoring without combustion in the internal combustion engine 1, so the internal combustion engine 1 can be inspected at low cost.

In this embodiment, the compressor 2 is used as a pressurizing mechanism for pressurizing the air introduced into the intake passage 11, but the pressurizing mechanism is not necessarily limited to this as long as the gas introduced into the intake passage 11 can be pressurized. Also, the gas introduced into the intake passage 11 is not limited to air. For example, an inert gas such as nitrogen or argon may be introduced into the intake passage 11 from a pressurized cylinder.

Further, in the present embodiment, the internal combustion engine 1 uses the variable compression ratio mechanism 15 using a multi-link type piston crank mechanism. good too. In this case, the inspection target can be the crank mechanism, and it can be determined whether the crank mechanism is normal or not from the vibration information of the main body of the internal combustion engine 1 .

Furthermore, the object to be inspected is not limited to the crank mechanism, and the inspection items are not limited to the presence or absence of seizure or the like. For example, an abnormality determination may be made for a piston slap sound or the like in the piston 14, or an abnormality determination may be made for a hammering sound caused by vibration of the main body of the internal combustion engine 1.

Further, in the present embodiment, whether or not the compression ratio control mechanism 15B is normal is determined during motoring, but whether or not the compression ratio control mechanism 15B is normal is determined after motoring. good too. That is, after motoring for a predetermined time, the controller 7 may determine whether or not the vibration is normal based on the vibration data detected during the motoring after the motoring is finished.

In the present embodiment, the vibration sensor 6 detects the vibration of the main body of the internal combustion engine 1 as a parameter for determining whether the compression ratio control mechanism 15B, which is the part to be inspected, is normal. is not limited to this. For example, after motoring for a predetermined period of time, a contamination detection sensor may detect foreign matter in the oil in the cylinder block, and based on the detection information, it may be determined whether or not the portion to be inspected is normal. The parameter to be detected is not particularly limited as long as it can be determined whether or not the test object is normal.

In addition, in order to suppress a decrease in the in-cylinder pressure of the internal combustion engine 1 during the exhaust stroke, it is preferable to connect the intake passage 11 and the exhaust passage 12 and recirculate the exhaust gas as in the present embodiment, but this is not necessarily the case. Not limited. Even if the intake passage 11 and the exhaust passage 12 are not connected, the combustion pressure of the internal combustion engine 1 can be reproduced by motoring as long as the gas pressurized by the pressurizing mechanism 2 is supplied to the intake passage 11. be able to. That is, it is possible to provide an inspection method for the internal combustion engine 1 that is low in cost and that sufficiently guarantees the functions and performance of the internal combustion engine 1 .

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. do not have.

1 Internal Combustion Engine 2 Compressor 3 Constant Pressure Valve 4 Circulation Passage 5 Surge Tank 6 Vibration Sensor 7 Controller 11 Intake Passage 12 Exhaust Passage 13 Cylinder 14 Piston 15 Variable Compression Ratio Mechanism 16 Combustion Chamber 100 Internal Combustion Engine Inspection Device

Claims (12)

An internal combustion engine inspection method for inspecting whether an internal combustion engine is normal using an internal combustion engine inspection device,
an introduction step of introducing into an intake passage of the internal combustion engine a gas pressurized to a pressure that can reproduce the cylinder pressure in the combustion process of the internal combustion engine by the pressurization mechanism of the inspection device;
a motoring step of motoring the internal combustion engine;
During or after the motoring, a value of a parameter capable of determining whether the internal combustion engine is normal is detected, and it is determined whether the internal combustion engine is normal from the detected parameter value. a determining step;
Method for inspecting internal combustion engines. An inspection method for an internal combustion engine according to claim 1,
In the exhaust stroke of the motoring, the gas exhausted to the exhaust passage of the internal combustion engine is recirculated to the intake passage;
Method for inspecting internal combustion engines. An inspection method for an internal combustion engine according to claim 2,
The inspection device includes a constant pressure valve between the pressurizing mechanism and the intake passage,
In the introduction step, the gas pressurized by the pressurizing mechanism during the motoring is introduced into the intake passage together with the recirculated gas,
The constant pressure valve adjusts the amount of gas introduced from the pressurization mechanism so that the pressure of the gas introduced into the intake passage is maintained at a predetermined pressure.
Method for inspecting internal combustion engines. An internal combustion engine inspection method according to any one of claims 1 to 3,
The object to be inspected is the crank mechanism of the internal combustion engine,
The determining step includes detecting vibration of the internal combustion engine body with a vibration sensor and determining whether or not the crank mechanism is normal based on the detected information.
Method for inspecting internal combustion engines. An internal combustion engine inspection method according to any one of claims 1 to 3,
The object to be inspected is the crank mechanism of the internal combustion engine,
In the determination step, foreign matter in oil in a cylinder of the internal combustion engine is detected after the motoring is performed, and it is determined whether the crank mechanism is normal based on the detected information.
Method for inspecting internal combustion engines. The inspection method for an internal combustion engine according to claim 4 or 5,
The crank mechanism includes a link mechanism consisting of a plurality of links provided between a piston and a crankshaft, and a compression ratio control mechanism that regulates the attitude of the link mechanism to change the compression ratio,
The determining step determines whether or not the compression ratio control mechanism is normal.
Method for inspecting internal combustion engines. An inspection device for an internal combustion engine for inspecting whether the internal combustion engine is normal,
an internal combustion engine comprising an intake passage and an exhaust passage;
a pressurization mechanism for pressurizing the gas to be introduced into the internal combustion engine to a pressure that can reproduce the in-cylinder pressure in the combustion process of the internal combustion engine by motoring and supplying the gas to the intake passage;
a detection sensor that detects the value of a parameter that can determine whether the internal combustion engine is normal,
Inspection equipment for internal combustion engines. An inspection device for an internal combustion engine according to claim 7,
The intake passage and the exhaust passage are connected so that the gas exhausted to the exhaust passage is recirculated to the intake passage.
Inspection equipment for internal combustion engines. An inspection device for an internal combustion engine according to claim 8,
further comprising a constant pressure valve between the pressurizing mechanism and the intake passage;
The constant pressure valve adjusts the amount of gas introduced from the pressurization mechanism so that the pressure of the gas introduced from the pressurization mechanism into the intake passage becomes a predetermined pressure.
Inspection equipment for internal combustion engines. The inspection device for an internal combustion engine according to claim 8 or 9,
The exhaust passage and the intake passage are connected via a surge tank,
Inspection equipment for internal combustion engines. The internal combustion engine inspection device according to any one of claims 7 to 10,
The object to be inspected is the crank mechanism of the internal combustion engine,
The detection sensor is a vibration sensor that detects vibration of the internal combustion engine body,
Inspection equipment for internal combustion engines. The inspection device for an internal combustion engine according to claim 11,
The crank mechanism includes a link mechanism consisting of a plurality of links provided between a piston and a crankshaft, and a compression ratio control mechanism that regulates the attitude of the link mechanism to change the compression ratio.
Inspection equipment for internal combustion engines.

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