JP4827758B2 - Fault diagnosis device for variable valve timing control device - Google Patents

Description

The present invention relates to an improvement of a device for performing a failure diagnosis of a variable valve timing control device .

Conventionally, as a self-diagnosis device for a variable valve timing control device, there is a technique for determining a failure of a control device from a deviation between an actual intake air amount and a predicted value obtained by calculating an intake air amount from a throttle valve opening and a rotational speed.
JP-A-6-317114

  However, if the variable valve timing control device on the intake side fails, the intake air amount changes, and the above-mentioned deviation becomes large and it is possible to determine the failure. This technology was applied to an engine with a turbocharger. In this case, there is a problem that the change in intake air amount due to the action of the turbocharger cannot be dealt with, and as a result, the accuracy of failure diagnosis is lowered.

  Furthermore, assuming that the prior art is applied to the exhaust side, if the valve timing control device on the exhaust side fails, the intake air amount does not necessarily change, and a failure diagnosis is performed using the deviation of the intake air amount. There is a problem that can not be.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a variable valve timing control device failure diagnosis apparatus that solves the above-described problems.

According to a first aspect of the present invention, there is provided a failure diagnosing device for a variable valve timing control device that variably controls a valve timing of an intake valve of an engine with a turbocharger, the engine rotation speed detecting means for detecting the rotation speed of the engine, and the turbocharger. The boost pressure detecting means for detecting the pressure of the intake air supplied to the engine, the intake air amount detecting means for detecting the amount of air sucked into the engine, and the engine rotation when the variable valve timing control device is normal Based on the setting means for setting the relationship among the speed, the intake air amount and the supercharging pressure as reference characteristics, the detection value of the engine rotation speed detection means and the detection value of the intake air amount detection means, A reference value of the supply pressure is obtained, and the variable valve timing is determined based on a comparison between the reference value and a detection value of the supercharging pressure detection means. A failure diagnosis means for performing a fault diagnosis of the grayed controller, a trouble diagnosis device for the variable valve timing control apparatus according to claim. According to a second aspect of the present invention, there is provided a failure diagnosis device for a variable valve timing control device that variably controls a valve timing of an exhaust valve of an engine equipped with a turbocharger. A boost pressure detecting means for detecting the pressure of the intake air supplied to the engine, a fuel injection amount detecting means for detecting the fuel injection amount of the engine, and an engine speed when the variable valve timing control device is normal. The setting means for setting the relationship between the supercharging pressure and the fuel injection amount as a reference characteristic, the supercharging pressure from the setting means based on the detection value of the engine speed detection means and the detection value of the fuel injection amount detection means And a variable valve timing control based on a comparison between the reference value and the detected value of the supercharging pressure detecting means. A failure diagnosis means for performing a fault diagnosis of the device, a failure diagnosis device for a variable valve timing control apparatus comprising: a.

According to a third aspect of the present invention, there is provided a failure diagnosis device for a variable valve timing control device that variably controls a valve timing of an engine with a turbocharger, wherein an engine rotation speed detecting means for detecting the rotation speed of the engine and an engine via the turbocharger Boost pressure detecting means for detecting the pressure of the supplied intake air, intake air amount detecting means for detecting the amount of air sucked into the engine, fuel injection amount detecting means for detecting the fuel injection amount of the engine, and intake air A first setting means for setting, as a reference characteristic, a relationship between an engine speed, an intake air amount, and a supercharging pressure when a variable valve timing control device that variably controls a valve timing of the valve is normal; and the engine speed detecting means Based on the detected value of the intake air amount and the detected value of the intake air amount detecting means. A first failure diagnosis means for diagnosing a failure of the variable valve timing control device based on a comparison between the reference value and a detection value of the supercharging pressure detection means, and a variable for variably controlling the valve timing of the exhaust valve. Second setting means for setting, as a reference characteristic, a relationship among an engine speed, a supercharging pressure, and a fuel injection amount when the valve timing control device is normal; a detection value of the engine speed detection means; and a fuel injection amount detection A reference value of the boost pressure is obtained from the second setting means based on the detected value of the means, and the failure of the variable valve timing control device is determined based on a comparison between the reference value and the detected value of the boost pressure detecting means. A failure diagnosis device for a variable valve timing control device, comprising: a second failure diagnosis means for performing diagnosis .

In the first invention or the third invention , the reference value of the supercharging pressure is obtained from the reference characteristic based on the detection value of the engine speed detection means and the detection value of the intake air amount detection means, and the reference value and Since the failure diagnosis of the variable valve timing control device that variably controls the valve timing of the intake valve based on the comparison with the detection value of the supply pressure detection means, even if it is a variable valve timing control device of a turbocharged engine, the accuracy Often, variable valve timing control devices for intake valves can also perform fault diagnosis.

In the second or third aspect of the invention , the reference value of the supercharging pressure is obtained from the reference characteristic based on the detection value of the engine speed detection means and the detection value of the fuel injection amount detection means, and the reference value and Since the failure diagnosis of the variable valve timing control device that variably controls the valve timing of the exhaust valve based on the comparison with the detection value of the supply pressure detection means is performed , even if it is a variable valve timing control device of a turbocharged engine, the accuracy Often, a variable valve timing control device for an exhaust valve can also perform failure diagnosis.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an overall configuration diagram of a turbocharged engine to which a variable valve timing control device according to the present invention is applied.

  An engine 10 includes a so-called variable valve timing mechanism that can variably control the opening / closing timing of the intake / exhaust valves according to the operating state. An intake manifold 12 is connected to the engine 10, and intake air purified by an air cleaner 16 is introduced from the intake passage 14. Here, the engine 10 may be a gasoline engine or a diesel engine. The configuration of the variable valve timing mechanism provided in the engine 10 may be a known configuration, for example, the configuration described in Patent Document 1.

  A compressor 18A of the turbocharger 18 is disposed in the middle of the intake passage 14, and an intercooler 20 for cooling the intake air heated by the action of the compressor 18A is installed downstream of the compressor 18A.

  An exhaust manifold 22 for discharging exhaust gas is connected to the engine 10, and an exhaust passage 24 is connected to the exhaust manifold 22. The exhaust gas is purified by a purification means (not shown) and discharged to the outside. In the middle of the exhaust passage 24, the turbine 18B of the turbocharger 18 is disposed. The kinetic energy of the exhaust rotates the turbine 18B, and the compressor 18A connected to the turbine 18B rotates. The intake air is supercharged by the rotation of the compressor 18A, and the supercharged intake air is introduced into the engine 10.

  A variable valve timing control device 26 for variable valve timing control of the engine 10 is installed. The variable valve timing control device 26 includes an intake air temperature sensor 28 for detecting the intake air temperature, an intake air pressure sensor 30 for detecting the intake air pressure upstream of the turbocharger 18, an intake air amount sensor 32 for detecting the intake air flow rate, and the rotation of the turbocharger 18. The output signal of the turbo rotation sensor 34 that detects the speed is input.

  Further, the variable valve timing control device 26 includes a supercharging pressure sensor 36 that detects the pressure of the intake air (= supercharging pressure) downstream of the turbocharger 18, an engine rotation sensor 38 that detects the rotational speed of the engine 10, and the exhaust temperature. Output signals of the exhaust temperature sensor 40 to be detected and the accelerator opening sensor 42 to detect the opening of the accelerator pedal are input. In the case of a gasoline engine, the supercharging pressure sensor 36 is installed downstream of the throttle valve.

Next, failure diagnosis (self-failure diagnosis) of the variable valve timing control device 26 will be described separately for the intake valve and the exhaust valve.

  First, in the self-failure diagnosis of the variable valve timing control device 26 for the intake valve of the present invention, the reference relationship between the supercharging pressure and the intake air amount is obtained in advance by experiment or the like for each predetermined engine speed, and the variable valve timing is determined. This is characterized in that a fault diagnosis is performed by storing the first map in the control device 26 and comparing the reference characteristic with the actual detection value.

  During normal variable valve timing control, the intake valve timing changes according to the operating state. At this time, the relationship between the supercharging pressure and the intake air amount at each engine speed is shown as a characteristic shown in FIG. When the variable valve timing control device 26 of the intake valve breaks down, for example, the kinetic energy that the exhaust gives to the turbocharger 18 changes, and the intake air amount does not change even if the supercharging pressure changes. Therefore, a failure diagnosis of the intake side variable valve timing control device 26 can be performed by comparing the change in the characteristic with the reference characteristic.

  The self-failure diagnosis of the variable valve timing control device 26 for the intake valve will be described below using the flowchart of FIG. This failure diagnosis is performed at predetermined intervals.

  In steps S1 to S3, the engine speed, the intake air amount, and the supercharging pressure are read using each sensor.

  The first map showing the reference characteristic of the intake air amount and the boost pressure as shown in FIG. 3 corresponding to the read engine rotation speed, and the region where the intake air amount and the boost pressure read in step S4 perform fault diagnosis It is determined whether or not. As shown in FIG. 3, this region is set so as not to make a failure determination when the intake air amount is small or the supercharging pressure is low, and is stored in the variable valve timing control device 26 in advance. In this region, even if a failure of the variable valve timing control device 26 occurs, it is considered that the influence is small, so failure diagnosis is not performed in this region. The first map shows characteristics serving as a reference for the intake air amount and the supercharging pressure, and the other reference value within a predetermined range can be set from one value using this map.

  In the following step S5, an allowable boost pressure (or intake air amount) is calculated based on the intake air amount (or boost pressure) detected from the read first map, and the boost pressure detected in step S6 is calculated. It is compared whether or not it is within the range of the allowable boost pressure, and if it is within the range, it is determined that it is normal (step S7). If it is outside the allowable range, it is determined that the variable valve timing control device 26 has failed (step S8). If it is determined that the variable valve timing device 26 has failed, the process proceeds to step S9, and a failure processing routine for coping with the failure is performed.

  The OK region shown in the first map shown in FIG. 3 indicates an allowable range for the design value indicated by the solid line, and is set based on experiments or the like in advance.

  In the self-diagnosis device of the variable valve timing control device 26 for the intake valve, the present invention stores the reference characteristics of the supercharging pressure and the intake air amount in advance as a map in the variable valve timing control device 26 for each engine speed. The actual engine speed, supercharging pressure, and intake air amount are detected, and the reference supercharging pressure is set from the actual engine speed and intake air amount, and compared with the actual supercharging pressure. Since the failure of the variable valve timing control device 26 for the intake valve is diagnosed, the failure of the variable valve timing control device 26 for the intake valve can be accurately determined based on the change in the supercharging pressure.

  Next, the self-failure diagnosis of the variable valve timing control device 26 for the exhaust valve will be described.

  In the self-failure diagnosis of the variable valve timing control device 26 of the exhaust valve according to the present invention, a relationship that serves as a reference between a supercharging pressure (or intake air amount) and a load (for example, fuel injection amount or accelerator opening) is set to a predetermined value. It is characterized in that a failure diagnosis is performed by previously finding it by experiment or the like for each engine rotation speed and storing it as a second map in the variable valve timing control device 26, and comparing this reference characteristic with the actual detection value. .

  Relationship between supercharging pressure (or intake air amount) for each engine speed and fuel injection amount (or accelerator opening) during normal variable valve timing control when the exhaust valve timing is changed according to the operating state Is shown as a characteristic as shown in FIG. When the variable valve timing control device 26 of the exhaust valve fails, the exhaust valve timing changes, the kinetic energy that the exhaust gives to the turbocharger 18 changes from the normal state, and the supercharging pressure and the intake air amount change. Therefore, a failure diagnosis of the exhaust-side variable valve timing control device 26 can be performed by comparing the change in the characteristic with the reference characteristic.

  Hereinafter, the self-failure diagnosis of the variable valve timing control device 26 will be described with reference to the flowchart of FIG. This failure diagnosis is performed at predetermined intervals.

  In steps S1, S10, and S3, the engine speed, the fuel injection amount, and the supercharging pressure are read using each sensor.

  The second map indicating the reference characteristic of the fuel injection amount and the boost pressure as shown in FIG. 5 corresponding to the read engine rotation speed is read, and the region in which the fuel injection amount and the boost pressure read in step S4 perform fault diagnosis It is determined whether or not. This region is set so as not to make a failure determination when the fuel injection amount is small or the supercharging pressure is low as shown in FIG. 5, and is stored in advance in the variable valve timing control device 26. In this region, even if a failure of the variable valve timing control device 26 occurs, it is considered that the influence is small, so failure diagnosis is not performed in this region. Note that the second map shows characteristics serving as a reference for the fuel injection amount and the supercharging pressure, and the other reference value in a predetermined range can be set from one value using this map.

  In the following step S11, an allowable supercharging pressure (or fuel injection amount) is calculated based on the fuel injection amount (or supercharging pressure) detected from the read second map, and the supercharging pressure detected in step S6 is calculated. It is compared whether or not it is within the range of the allowable boost pressure, and if it is within the range, it is determined that it is normal (step S7). If it is outside the allowable range, it is determined that the variable valve timing control device 26 has failed (step S8). If it is determined that the variable valve timing device 26 has failed, the process proceeds to step S9, and a failure processing routine for coping with the failure is performed.

  The accelerator opening may be used instead of the fuel injection amount, and the intake air amount may be used instead of the supercharging pressure. The OK region shown in the second map shown in FIG. 5 indicates an allowable range for the design value indicated by the solid line, and is set based on experiments or the like in advance.

In the self-diagnosis device of the exhaust-side variable valve timing control device 26, the present invention stores the reference characteristics of the boost pressure and the fuel injection amount in advance as a map in the variable valve timing control device 26 for each engine speed. The actual engine speed, supercharging pressure, and fuel injection amount are detected, and the reference supercharging pressure is set from the actual engine speed and fuel injection amount and compared with the actual supercharging pressure. Since the failure of the variable valve timing control device 26 for the exhaust valve is diagnosed, the failure of the variable valve timing control device 26 for the exhaust valve can be accurately determined based on the change in the supercharging pressure.

  In the embodiment described so far, the failure diagnosis is performed based on the change in the supercharging pressure. However, the present invention is not limited to this. For example, the upstream or downstream of the turbine 18B of the turbocharger 18 can be detected. The temperature may be detected and compared with a reference temperature for failure diagnosis.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

1 is an overall configuration diagram of a turbocharged engine of an embodiment. It is a flowchart which determines the failure of valve timing control on the intake side. It is a map used at the time of failure determination of valve timing control on the intake side. It is a flowchart which determines the failure of valve timing control on the exhaust side. It is a map used at the time of the failure determination of the exhaust side valve timing control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 12 Intake manifold 14 Intake passage 16 Air cleaner 18 Turbocharger 18A Compressor 18B Turbine 20 Intercooler 22 Exhaust manifold 24 Exhaust passage 26 Controller 28 Intake air temperature sensor 30 Intake pressure sensor 32 Intake air amount sensor 34 Turbo rotation sensor 36 Supercharging pressure Sensor 38 Engine rotation sensor 40 Exhaust temperature sensor 42 Accelerator opening sensor

Claims (3)

In the fault diagnosis device of the variable valve timing control device that variably controls the valve timing of the intake valve of the turbocharged engine,
Engine rotation speed detection means for detecting the rotation speed of the engine;
Supercharging pressure detecting means for detecting the pressure of intake air supplied to the engine via the turbocharger;
Intake air amount detection means for detecting the amount of air taken into the engine;
Setting means for setting, as a reference characteristic, a relationship among the engine rotation speed, the intake air amount, and the supercharging pressure when the variable valve timing control device is normal ;
Based on the detection value of the engine rotation speed detection means and the detection value of the intake air amount detection means, a reference value of supercharging pressure is obtained from the setting means, and this reference value and the detection value of the supercharging pressure detection means Failure diagnosis means for performing failure diagnosis of the variable valve timing control device based on the comparison of
A fault diagnosis device for a variable valve timing control device . In the fault diagnosis device of the variable valve timing control device that variably controls the valve timing of the exhaust valve of the turbocharged engine,
Engine rotation speed detection means for detecting the rotation speed of the engine;
Supercharging pressure detecting means for detecting the pressure of intake air supplied to the engine via the turbocharger;
Fuel injection amount detection means for detecting the fuel injection amount of the engine;
Setting means for setting, as a reference characteristic, a relationship among the engine rotation speed, the supercharging pressure, and the fuel injection amount when the variable valve timing control device is normal ;
Based on the detection value of the engine rotation speed detection means and the detection value of the fuel injection amount detection means, a reference value of supercharging pressure is obtained from the setting means, and this reference value and the detection value of the supercharging pressure detection means Failure diagnosis means for performing failure diagnosis of the variable valve timing control device based on the comparison of
A fault diagnosis device for a variable valve timing control device comprising: In a fault diagnosis device for a variable valve timing control device that variably controls the valve timing of a turbocharged engine,
Engine rotation speed detection means for detecting the rotation speed of the engine;
Supercharging pressure detecting means for detecting the pressure of intake air supplied to the engine via the turbocharger;
Intake air amount detection means for detecting the amount of air taken into the engine;
Fuel injection amount detection means for detecting the fuel injection amount of the engine;
First setting means for setting, as a reference characteristic, a relationship among the engine speed, the intake air amount, and the supercharging pressure when the variable valve timing control device that variably controls the valve timing of the intake valve is normal;
Based on the detection value of the engine speed detection means and the detection value of the intake air amount detection means, a reference value of the boost pressure is obtained from the first setting means, and the reference value and detection of the boost pressure detection means First failure diagnosing means for diagnosing the variable valve timing control device based on a comparison with a value;
Second setting means for setting, as a reference characteristic, a relationship among the engine speed, the supercharging pressure, and the fuel injection amount when the variable valve timing control device that variably controls the valve timing of the exhaust valve is normal;
Based on the detection value of the engine speed detection means and the detection value of the fuel injection amount detection means, a reference value of the boost pressure is obtained from the second setting means, and the reference value and detection of the boost pressure detection means Second failure diagnosis means for performing failure diagnosis of the variable valve timing control device based on comparison with a value;
A fault diagnosis device for a variable valve timing control device comprising:

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