JPH06248986A - Malfunction detecting device for valve timing control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a low-cost valve timing control device to obviate the need to mount a special sensor by using an existing number of revolutions of engine detecting means. CONSTITUTION:An ECU 23 is operated to effect duty control of a valve timing and a solenoid valve 14, which a valve timing mechanism comprises, according to the operation state of an engine 1. A number of revolutions of engine sensor 22 is operated to output the number of revolutions of an engine to the ECU 23. A difference between a maximum value and a minimum value of a time between signals detected at intervals of 30 deg. is determined by the ECU 23 to compare an abnormality decision level and the difference. When the difference exceeds the abnormality value decision level, a trouble alarm signal is outputted by the ECU 23 to a display arranged at a driver's seat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a malfunction detecting device for a valve timing control device in an engine.

[0002]

2. Description of the Related Art Conventionally, this type of valve timing control device sets a valve timing based on the load of the engine and the number of revolutions of the engine so that a desired characteristic can be maximized by the port pressure. Is being corrected. If the valve timing mechanism that varies the valve timing of this valve timing control device malfunctions, for example, if it is fixed at a position where the overlap becomes large in the idle state, the residual gas ratio becomes large, so that combustion There is a problem that it becomes unstable and causes fuel consumption deterioration, vehicle vibration, engine stall, and the like. Also, if the valve timing mechanism malfunctions in other operating areas such as traveling, the output will decrease,
There is also a possibility that fuel efficiency will deteriorate.

Therefore, in the prior art, when the valve timing mechanism malfunctions, in order to detect this state, in JP-A-64-110844, the operation of the valve timing control device is directly detected. For example, a rocker arm. A motion sensor is provided. In addition, JP-A-2-30
As disclosed in Japanese Patent No. 8913, an intake pressure sensor is provided as means for detecting abnormality of the valve timing control device, and abnormality detection of the valve timing control device is performed based on the intake pressure detected by this intake pressure sensor. It is also suggested to do. Further, in JP-A-3-9010, an intake air amount detection sensor is provided to detect an abnormality in the valve timing control device, and abnormality detection of the valve timing control device is performed based on the intake air amount detected by the intake air amount detection sensor. Some have been suggested to do so.

[0004]

However, in order to detect an abnormality in the valve timing control device as described above,
There is a problem that a new sensor or the like is required. For example, in the case of a V-type engine, the valve timing (overlap) of the valve timing mechanism in each bank is different due to the design restrictions of the intake / exhaust system specifications and the dimensional errors of the valve operating system parts such as the timing belt and cam pulley. There may be a difference in intake air amount between the two. If the intake air amount differs between banks, it becomes difficult to suppress torque fluctuation, the air-fuel ratio controllability deteriorates, and the output cannot be improved. Further, during idle, combustion becomes unstable due to the overlap change, which is disadvantageous for idle vibration and the like. Therefore, when the valve timing control device becomes defective, it is necessary to warn the driver of this. However, conventionally, it was necessary to mount a new sensor as described above, and there was a problem that the cost increased.

It is an object of the present invention to provide an inexpensive malfunction detection device for a valve timing control device by using an existing engine speed detecting means without the need for mounting a special sensor.

[0006]

In order to solve the above problems, the present invention comprises drive control means for driving and controlling a valve timing mechanism according to the operating state of the engine so as to variably control the valve timing of the engine. In the valve timing control device, the engine rotation fluctuation amount detecting means for detecting the engine rotation fluctuation amount and the rotation fluctuation amount detected by the engine rotation fluctuation amount detecting means are compared with a predetermined reference value to determine the engine rotation fluctuation amount. Is large, the valve timing control device is provided with a determination means for determining that the abnormality.

[0007]

With the above construction, the drive control means controls the valve timing of the engine in accordance with the operating state of the engine to drive the valve timing mechanism. When a malfunction occurs in the valve timing control device, the engine rotation fluctuation amount fluctuates compared to the normal time, so the determination means compares the rotation fluctuation amount detected by the engine rotation fluctuation amount detection means with a predetermined reference value, When the rotation fluctuation amount is large, it is determined that the valve timing control device is abnormal.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the valve timing device for an internal combustion engine according to the present invention will be described below with reference to FIGS.

FIG. 1 shows a schematic configuration diagram of a four-cylinder gasoline engine applied to a malfunction detecting device of a valve timing control device of the present invention. Here, the operation control and valve timing control of the gasoline engine 1 are assumed to be well-known controls, and a description thereof will be omitted. Only the malfunction detection device will be described.

On the intake camshaft 5 side provided in each cylinder, a lift of an intake valve (not shown) driven to open and close by the camshaft 5 and a VV for varying the working angle are provided.
T (valve timing mechanism) is provided.

This VVT has a built-in actuator (not shown) driven by hydraulic pressure. These VV
The configuration of T is already well known, and a detailed description thereof will be omitted here. Further, a hydraulic circuit 9 for adjusting the supply of hydraulic pressure to the VVT is provided. This hydraulic circuit 9 is VV
It is composed of an oil passage 10 communicating with T, and a pump unit 15 including a hydraulic pump 13 and an electromagnetic valve 14 for pumping the working oil of the tank 12. When the VVT is hydraulically driven, the point of action of the camshaft forming the VVT with respect to the cam on the rocker arm is changed, whereby the lift amount of the intake valve driven by the rocker arm is made variable, The valve timing is adjusted. The pump unit 15 is the engine 1
It is also possible to share it with the oil pump that is installed in advance.

A crank pulley 16 is fixed to one end of the crankshaft 2. Further, one timing belt 17 is looped between the timing pulleys 7 and 8 provided at one end of each of the intake and exhaust camshafts 5 and 6 and the crank pulley 16, and each of the camshafts 5 and 6 is connected to the crankshaft. 2 is drivingly connected. Also, engine 1
Includes an idler 19 and a tension pulley 20 for applying a required tension to the timing belt 17 that is suspended.
Is provided. The timing pulley 7 of the intake camshaft 5 is provided with a cam rotation speed sensor 21 as an engine rotation speed sensor for detecting the rotation speed of the camshaft 5. The cam rotation speed sensor 21 has a crank angle of 3
A corresponding reference signal (hereinafter referred to as NE signal) is detected every 0 ° (hereinafter referred to as 30 ° CA), and the signal is output.

An intake passage 25 and an exhaust passage (not shown) communicate with the combustion chamber of each cylinder. An intake valve for opening and closing is attached to an intake port opening to the combustion chamber of the intake passage 25. Further, an exhaust valve for opening and closing is attached to the exhaust port opening to the combustion chamber of the exhaust passage. Outside air is introduced into the intake passage 25 through an air cleaner (not shown). An injector (not shown) for injecting fuel is provided in the intake passage 25 in the vicinity of the intake port so that the fuel is taken into the intake passage 25. In the middle of the intake passage 25, a throttle valve 26 that is opened / closed in association with the operation of an accelerator pedal (not shown) is provided. Then, by opening and closing the throttle valve 26, the intake passage 25
The intake air amount to the air is adjusted.

In the vicinity of the throttle valve 26, there are a throttle sensor 27 for detecting the throttle opening, and a fully closed switch 27a which is turned on when the throttle valve 26 is at the fully closed position and outputs a fully closed signal. Each is provided. Further, on the downstream side of the throttle valve 26, the surge tank 2 for smoothing the pulsation of the intake air amount
8 are provided. Further, a well-known air flow meter 29 that detects the amount of intake air taken into the intake passage 25 from the outside is provided upstream of the throttle valve 26.

The cam rotation speed sensor 21, the throttle sensor 27, the fully closed switch 27a, etc. constitute an electronic control unit (EC) which constitutes a judgment means and a drive control means.
U) 23 is connected to the input side. The electromagnetic valve 14 of the pump unit 15 is connected to the output side of the ECU 23. This ECU 23 is a central processing unit (C
PU), a read-only memory (ROM), and a read / write rewritable memory (RAM). Various control maps such as the VVT control map shown in FIG. 3 are stored in the ROM. Note that timing A shown in FIG. 3 is a region where the lift amount and working angle are small, and timing B is a region where the lift amount and working angle are large.

Then, the ECU 23 controls the electromagnetic valve 14 in order to control the valve timing according to the operating state of the engine 1, that is, based on the detection values of the sensors 21 and 22.
Is preferably duty controlled. In this embodiment, the ECU 23 calculates the engine speed (NE) and the intake air amount based on the detection signal from the engine speed sensor 22 and the detection signal from the air flow meter 29, and these values are used as parameters. The electromagnetic valve 14 is controlled based on the VVT control map. In addition,
Since this VVT control is publicly known, a detailed description thereof will be omitted. However, the parameters adopted for the VVT control may be the throttle opening, the vehicle speed, etc. in addition to the intake air amount and the engine speed. Good.

The operation of the malfunction detecting device in the valve timing control device for an internal combustion engine constructed as described above will be described with reference to FIG. The flowchart in FIG. 2 is E
Among the routines executed by the CU 23, the VVT malfunction determination routine is shown. This malfunction determination routine is executed by the ECU 23 by a regular interruption for a predetermined time.

When the processing shifts to this routine, it is judged at step 101 whether or not it is in the idle state. This determination is made based on whether or not the fully closed signal of the fully closed switch 27a of the throttle valve 26 is on. When the fully closed signal is not on, that is, when it is determined that the signal is not in the idle state, the process proceeds to step 111, the counter C is reset to 0, and this routine is once ended. When the fully closed signal is on, that is, when it is determined that the idle state is set, the counter C is incremented in step 102 and the process proceeds to step 103. This counter C is for counting how many times this processing routine has been passed.

At step 103, the current value of the time between NE signals detected at every 30 ° CA (hereinafter referred to as T30) is compared with the maximum value T30MAX so far. Current value T
If 30 is not less than the maximum value T30MAX, the current value T30 is stored in the RAM in step 104, and the process proceeds to step 107. If the current value T30 is smaller than the maximum value T30MAX in step 103, the current value T30 is compared with the minimum value T30MIN in step 105. Current value T30
Is smaller than the minimum value T30MIN, the current value T30 is stored in the RAM in step 106, and the process proceeds to step 107. In step 105, the current value T30 is the minimum value T3.
If it is larger than 0MINS, the process proceeds to step 107.

In step 107, it is determined whether or not the counter C is N times. That is, it is determined whether or not this processing routine has been rotated N times. If it has not reached N times, this processing routine is once ended. If it has reached N times, the minimum value T30MIN is subtracted from the maximum value T30MAX in step 108 to obtain the difference DT, and the process proceeds to step 109. In step 109, the abnormal value determination level T is compared with the difference DT. If the difference DT is less than the abnormal value determination level T, the process proceeds to step 111. The abnormal value determination level T is set as a normal value in the idle state, stored in the ROM, and read when entering this processing routine. Difference D in step 109
If T is equal to or higher than the abnormal value determination level T, the process proceeds to step 110. In step 110, the ECU 23 outputs a VVT failure warning signal to the display provided in the driver's seat, and the process proceeds to step 111. In step 111, the ECU 23 clears the counter C and temporarily ends this processing routine.

As described above, in this embodiment, due to the torque fluctuation of the cam, as shown in FIG. 4, T30 has two peaks and troughs per one revolution of the engine in four cylinders. In this embodiment, the VVT is such that the point of action of the camshaft forming the VVT on the rocker arm is changed, whereby the lift amount of the intake valve driven by the rocker arm is made variable. Therefore, the peak value and the amplitude differ depending on the working angle and the valve lift amount.

Therefore, when the VVT is abnormal, the above-mentioned processing routine detects the changes, and the abnormal operation of the VVT is judged based on the detection result. For example, in FIG. 4, the difference DT1 obtained by subtracting the minimum value T30MIN from the maximum value T30MAX at the time of idling at the time of abnormality
And the difference DT2 obtained by subtracting the minimum value T30MIN from the maximum value T30MAX at the time of idling in the normal state have different magnitudes. In this embodiment, by comparing the difference DT1 at the time of this abnormality with the abnormal value determination level T, the abnormal operation of the VVT can be detected.

Next, a modification of the above embodiment will be described with reference to FIGS. FIG. 5 illustrates a normal state and an abnormal state of T30 in the idle state of this embodiment.

In this embodiment, instead of the cam rotation speed sensor 21 as the engine rotation speed sensor in the construction of the above embodiment, the crankshaft 2 rotates in the same phase as the crankshaft 2 as shown in FIG. Engine speed sensor 2 for detecting the speed of the engine 1 (engine speed)
Two are provided. Further, the VVT configuration is of a known type in which the amount of overlap is variable, and when normal, a characteristic curve of T30 as shown in FIG. 5 is obtained. That is, when the valve overlap is large, combustion becomes unstable. Therefore, as shown in FIG. 5, the peak value and the amplitude are different between the case of abnormality indicated by the solid line and the case of normal state indicated by the dotted line.

Therefore, in this embodiment as well, from the maximum value T30MAX to the minimum value T3 in the case of idling at the time of abnormality
The difference DT1 obtained by subtracting 0MIN and the difference D obtained by subtracting the minimum value T30MIN from the maximum value T30MAX during idling under normal conditions.
The size is different from T2. Therefore, also in the present embodiment, the difference DT1 at the time of abnormality is set to the abnormal value determination level T
By comparing with, it is possible to detect the abnormal operation of the VVT.

Next, a multi-cylinder V type (V type 6 in this embodiment)
An embodiment embodied in a (cylinder) gasoline engine will be described with reference to FIGS. In the configuration of the above embodiment,
Corresponding configurations are assigned the same reference numerals and explanations thereof are omitted.

FIG. 6 shows a schematic configuration diagram of this gasoline engine. In this embodiment, each cylinder of the multi-cylinder V-type engine 31 is divided into two left and right positions with the crankshaft 32 as the center, and the left and right banks 33,
34 are configured.

An intake camshaft 3 is provided in each cylinder of each bank.
5A, 36A and exhaust camshafts 35B, 36B are provided. On the intake camshafts 35A and 36A side provided in each cylinder of each bank, the same camshaft 35 is provided.
A lift (not shown) of an intake valve, which is driven to open and close by A, 36A, and a VVT (valve timing mechanism) that makes the working angle variable are provided. When the VVT is hydraulically driven, the point of action of the camshaft forming the VVT with respect to the cam on the rocker arm is changed, whereby the lift amount of the intake valve driven by the rocker arm is made variable, The valve timing is adjusted. The camshafts 35A, 36A, 3
5B and 36B have cam pulleys 37, 38, 39, and
40 is fixed.

The crank pulley 16 is fixed to one end of the crank shaft 32. And each cam pulley 3
A single timing belt 17 is mounted between 7, 38, 39, 40 and the crank pulley 16, and each camshaft 35A, 36A, 35B, 36B is drivingly connected to the crankshaft 32. Further, the engine 31 is provided with idlers 18 and 19 and a tension pulley 20 for applying a required tension to the timing belt 17 mounted on the engine 31.

The engine number sensor 41 of the camshaft 36A of the right bank 34 is rotated by the engine 1 rotating at the same phase as the crankshaft 2 (engine speed) NE.
It is designed to detect Also, the camshaft 36B
Is provided with a reference position sensor 43 which detects a crank angle reference position of the engine 1 at a predetermined rate (once in every 360 ° in this embodiment) and outputs a reference signal G thereof.
The phase difference sensor 4 is attached to the camshaft 35A of the left bank 33.
Two are provided. The phase difference sensor 42 detects a position deviated by a predetermined amount of phase from the crank angle reference position of the engine 1 at a predetermined ratio (in this embodiment, once every 360 °) and outputs a phase difference signal S. That is, the reference position sensor 43 is detected so as to have a phase difference with respect to the reference signal G output.

The engine speed sensor 41,
The phase difference sensor 42, the reference position sensor 43, etc. are the ECU 23.
Is connected to the input side of. Now, in this embodiment, the engine is a V-type 6-cylinder engine, and one bank has 3 cylinders. Therefore, as shown in FIG.
There are three peaks and valleys during two revolutions of. Further, in this embodiment, the VVT of the right bank 34 has its point of action on the rocker arm with respect to the cam of the camshaft forming the VVT changed, whereby the lift amount of the intake valve driven by the rocker arm is made variable. It is a thing. Therefore, the peak value and the amplitude differ depending on the working angle and the valve lift amount.

The abnormal operation of the VVT on the right bank 34 side is detected by the processing routine of FIG. 2 executed by the ECU 23 similar to that of the first embodiment. Further, the abnormal operation of the VVT on the left bank 33 side is detected by the processing routine shown in FIG. 9 which is executed by the ECU 23 by the regular interruption for a predetermined time after the processing routine of FIG. 2 is finished.

That is, when this processing routine is entered, the ECU 23 calculates the interval TVVT between the reference signal G and the phase difference signal S in step 201, and compares the preset reference value T1 with the interval TVVT in step 202.
The reference value T1 is the same as or slightly smaller than the normal phase difference (interval) in the idle state as described above, and is stored in the ROM in advance. Step 20
If it is not less than the reference value T1 in 2, the processing routine is once ended. In step 202, the reference value T
If it is less than 1, in step 203, the ECU 23 outputs a VVT failure warning signal to the display provided in the driver's seat, and this processing routine is ended once.

That is, when the VVT malfunctions, it is known in advance that the phase difference signal S deviates to the advance side with respect to the reference signal G. Therefore, the phase difference signal S input by the ECU 23 is in this state. And the reference signal G.

Therefore, in this embodiment, on the right bank 34 side where the engine speed sensor 41 is provided, a malfunction of the VVT is detected by the engine speed sensor 41, and in the left bank 33, the reference position sensor 43 and the phase difference sensor 42. Detects a malfunction of VVT.

Thus, in this embodiment, the right bank 34
The engine speed sensor 41 can detect an abnormal VVT operation. Even if the engine speed sensor 41 is conventionally provided, unlike the present embodiment, both banks 33, 34 are provided.
Although it was necessary to provide the phase difference sensor in the above, in the present embodiment, it suffices to provide the phase difference sensor only in one bank where the engine speed sensor 41 is not provided.

The present invention is not limited to the above-mentioned embodiments, and can be arbitrarily modified within a range not departing from the spirit of the present invention. (1) The present invention is not limited to the V-type engine, but includes intake air,
It is also possible to embody one of the types of engine in which the VVT is provided on the exhaust camshaft side so that malfunction detection can be performed by the engine speed sensor.

(2) In the above embodiment, the gasoline engine 1 is embodied, but it may be embodied as a diesel engine.

[0039]

As described above in detail, according to the present invention, since the existing engine speed detecting means is used, it is not necessary to mount a special sensor, and thus the malfunction detecting device for the inexpensive valve timing control device is provided. There is an excellent effect that it can be.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a gasoline engine in an embodiment embodying the present invention.

FIG. 2 is a flow chart for explaining a VVT malfunction processing routine.

FIG. 3 is an explanatory diagram of a map for performing VVT control.

FIG. 4 is an explanatory diagram for explaining normal times and abnormal times of T30 according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram for explaining normal times and abnormal times of T30 according to another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram in another embodiment in which the present invention is embodied in a V-type engine.

FIG. 7 is an explanatory diagram for explaining a normal state and an abnormal state of T30 of another embodiment.

FIG. 8 is an explanatory diagram for explaining a reference signal and a phase difference signal of another embodiment.

FIG. 9 is a flowchart for explaining a VVT malfunction processing routine.

[Explanation of symbols]

1 ... Engine as internal combustion engine, 9 ... Hydraulic circuit, 10,
11 ... Oil passage, 14 ... Electromagnetic valve, 22 ... Engine speed sensor, 23 ... ECU as drive control means, 25 ... Intake passage, 33 ... Left bank, 34 ... Right bank, 41 ... Engine speed sensor, 42 ... Phase difference sensor, 43 ... Reference position sensor.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G01M 15/00 Z 7324-2G

Claims (1)

[Claims] 1. A valve timing control device comprising a drive control means for driving and controlling a valve timing mechanism according to an operating state of the engine so as to variably control the valve timing of the engine, the engine detecting a rotational fluctuation amount of the engine. Rotational fluctuation amount detection means, comparing the rotational fluctuation amount detected by the engine rotational fluctuation amount detection means with a predetermined reference value, when the engine rotational fluctuation amount is large, it is determined that the valve timing control device is abnormal And a malfunction detecting device for a valve timing control device of an internal combustion engine.