JPH0746737Y2 - Control device for engine with supercharger - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a control device for an engine with a supercharger, and in particular, to a device incorporating measures against abnormal conditions of a relief valve that relieves supercharged air during deceleration.

[Prior art]

Conventionally, in a supercharged engine, as described in Japanese Patent Laid-Open No. 59-29726, in order to prevent the supercharger and the air flow meter from being damaged by excessive supercharging pressure during deceleration of the engine. , A relief passage bypassing the turbocharger in the intake passage and a relief valve (air bypass valve) interposed in the relief passage, and the relief valve is opened at the time of deceleration so that the supercharging air is discharged from the relief passage upstream of the supercharger. It is designed to relieve the intake passage.

On the other hand, in recent engines, a duty solenoid IS is installed in the bypass passage that bypasses the throttle valve in the intake passage.
The C valve (idle speed control valve) is installed to precisely control the engine speed during idling.

[Problems to be solved by the device]

In the above engine with a supercharger, combustion gas may flow into the intake passage due to blowback from the combustion chamber, and when the blowback is significant, the combustion gas may be blown back to the air cleaner. Further, since the blow-by gas of the engine is introduced into the intake passage, sludge and oil also flow into the intake passage.

Such foreign matter such as carbon, sludge, and oil may flow into the intake passage and the relief passage around the intake passage, and the valve body of the relief valve may be stuck with the carbon or oil to cause a failure.

If the relief valve fails in this way and the throttle valve is closed during engine deceleration, excess supercharging will not be relieved and its pressure will increase, causing the turbocharger's rotating shaft system to seize or become abnormally abnormal. The pulsation of the supply pressure propagates through the supercharger to the upstream side of the intake passage, causing a problem that the measuring plate of the air flow meter repeatedly vibrates and fails.

An object of the present invention is to provide a control device for an engine with a supercharger that can surely relieve supercharged air during deceleration even when a relief valve fails.

[Means for Solving the Problems]

A control device for a supercharged engine according to the present invention is provided with a supercharger and a throttle valve in an intake passage in order from an upstream side thereof, and a relief passage that bypasses the supercharger and a relief passage that opens during deceleration. In an engine provided with a valve, a bypass passage bypassing a throttle valve, an idle speed control valve interposed in the bypass passage, an abnormality detecting means for detecting an abnormality of the relief valve, and a deceleration detection for detecting an engine deceleration state. And a relief control means for receiving the outputs of both of the detection means and increasing the opening degree of the idle speed control valve during deceleration when the relief valve is in an abnormal state.

[Action]

In the control device for the engine with the supercharger according to the present invention,
Supercharging of intake air is performed by the supercharger in the intake passage, and the relief valve in the relief passage is opened during deceleration, so that the supercharged air is relieved to the intake passage upstream of the supercharger. Also, when the engine is idle, the intake air amount is adjusted via the idle speed control valve.

On the other hand, when the relief valve is in an abnormal state, it is detected by the abnormality detecting means, and the deceleration state of the engine is detected by the deceleration detecting means. The relief control means increases the opening degree of the idle speed control valve during deceleration when the relief valve is in an abnormal state. Therefore, the supercharged air flows to the intake port through the bypass passage, and the abnormal increase in the supercharging pressure is prevented.

In this case, the reduction of the engine speed is hindered,
Measures such as retard control of ignition timing can be taken.

[Effect of device]

According to the control device for a supercharged engine according to the present invention, as described above, by providing the bypass passage, the idle speed control valve, the abnormality detecting means, the relief control means, etc. The supercharged air trapped in the intake passage between the supercharger and the throttle valve during deceleration in an abnormal state can be reliably relieved by effectively utilizing the idle speed control valve normally provided in the engine.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

The present embodiment is an example of the case where the present invention is applied to a vertical turbocharged engine for an automobile.

As shown in FIG. 1, the intake passage 2 connected to the intake port 1 of the engine E has an air cleaner 3 in order from the upstream side.
The air flow meter 4, the blower 6B of the turbocharger 6, the intercooler 7, the throttle valve 8, the surge tank 9, and the injector 10 are provided, and the turbocharger 6 is provided in the exhaust passage 12 extending from the exhaust port 11. The turbine 6A and the catalytic converter 13 are provided.

The intake passage 2 is provided with a relief passage 14 that branches from a passage portion between the intercooler 7 and the throttle valve 8 and is connected to a passage portion on the upstream side of the blower 6B. (Bypass air valve) is installed.

The relief valve 15 has a structure in which the diaphragm 15c is pressed by the compression coil spring 15b of the negative pressure introducing chamber 15a to bring the valve seat 15d into contact with the partition member 15e, as shown in FIG.
The negative pressure introducing chamber 15a is connected to the surge tank 9 by the negative pressure introducing passage 16, and when the throttle valve 8 is closed, a large boost negative pressure is introduced into the negative pressure introducing chamber 15a, the diaphragm 15 is displaced upward, and the valve seat is closed. The space between 15d and the partition member 15e is opened.

The intake passage 2 is provided with a bypass passage 17 that bypasses the throttle valve 8. The bypass passage 17 is provided with a rotary ISC valve 18 (idle speed control valve) driven by a duty solenoid.

Regarding the control system of the engine E, in addition to the air flow meter 4, a crank angle sensor 20 for detecting the crank angle of the crankshaft 19, a throttle opening sensor 21 for detecting the opening of the throttle valve 8, and a throttle valve 8 ON when fully closed
An idle switch 22, which is used to set the temperature of the cooling water, and a water temperature sensor 23 that detects the temperature of the cooling water. The signal from the start / stop switch 25 of the control unit 30
Has been entered into.

The control unit 30 is for controlling the injector 10, the ISC valve 18, etc. based on the various detection signals, and A / D converts the detection signals from the sensors 4, 21, 23.
It is equipped with a / D converter, a waveform shaping circuit for shaping the crank angle signal, an input / output interface, a microcomputer, an injector drive circuit, and an ISC valve drive circuit. The ROM of the microcomputer is a control program for idle speed control, which will be described later performed via the ISC valve 18, which includes a supercharging relief control performed via the ISC valve 18, and an abnormality of the relief valve 15. A control program for the abnormality detection control to be detected is input and stored in advance.

First, the abnormality detection control will be described with reference to the flowchart of FIG. However, in the figure Si (i = 40, 41, ...
...) indicates each step.

When this control is started by interrupt processing for each crank angle of 180 ° based on the crank angle signal of the crank angle sensor 20,
Various necessary signals are read (S40), and it is judged from the signal from the neutral position switch 24 whether the gear position is in neutral (S41). When the signal is ON and in neutral, the process proceeds to S44 and the relief valve 15 is abnormal. The flag FG indicating that the relief valve 15 is abnormal is reset as none and the routine returns to the main routine.

Next, when it is not in neutral, it is determined whether or not the vehicle is in a deceleration state (S42). In this case, the engine speed N _e obtained from the interrupt cycle is N _e ≧ 2000 (rpm), the signal of the idle switch 22 is ON, and the detection signal from the throttle opening sensor 21 (previous throttle opening and current throttle opening). )
When the throttle opening reduction rate obtained in step S4 is larger than the predetermined value, it is determined that the vehicle is in the deceleration state, and the process proceeds to step S43. When it is not in the deceleration state, the process proceeds to S44.

In the deceleration state, it is judged whether or not | ΔV _S | ≧ α (predetermined threshold value) as the deviation ΔV _S (see FIG. 4) of the detection signal V _S of the air flow meter 4 (S43), and when No S because the relief valve 15 is normal
The routine proceeds to 44, and when the result is Yes, the relief valve 15 is abnormal, so the flag FG is set (S45), and then the routine returns to the main routine.

A supplementary explanation of the above abnormality determination will be made. When the relief valve 15 is normal, the detection signal V _S of the air flow meter 4 is
Although it oscillates with a small amplitude as shown by the curve A in the figure, if the relief valve 15 is locked in the closed state due to foreign matter or the like, the blower 6B and the throttle valve 8 when the throttle valve 8 is fully closed during deceleration.
The supercharged air confined in the intake passage 2 part between the two rises abnormally, and its pulsating pressure propagates to the upstream part of the intake passage 2 via the blower 6B, and the measuring plate of the air flow meter 4 vibrates and is detected. Since the signal V _S oscillates with a large amplitude as shown by the curve B in FIG. 4, the detection signal V _S of the predetermined number of times in the past is updated and stored in the memory, and the current detection signal V _{S with} respect to the time average value thereof is stored. The determination of S43 is performed by obtaining the deviation ΔV _S of. When the relief valve 15 becomes abnormal, the abnormality is surely detected during the execution of interrupt processing several times.

As described above, it is determined whether the relief valve 15 is normal or abnormal. When the relief valve 15 is normal, the flag FG is held at FG = 0, and when the relief valve 15 is abnormal, the flag FG is FG.
= 1 and this flag FG is used in the control described below.

Next, regarding the idle speed control and the supercharging air relief control included therein, the flowchart of FIG.
This will be described with reference to FIGS. In the figure, Si (i = 1,
2, ...) indicates each step, F / B is an abbreviation for feedback and ISC is an abbreviation for idle speed control.

When the control is started with the start of the engine E, necessary necessary signals are read after the necessary initialization such as clearing the RAM memory is executed (S1), and then whether or not the ISC feedback condition is satisfied. It is judged (S2). That is, the throttle valve 8 is fully closed and the signal of the idle switch 22 is ON,
In addition, the engine speed N _e obtained by separately calculating from the crank angle signal is N _e ≦ N _o (idle target speed) + β (for example, 300 rpm), and the gear position is neutral, and the signal of the neutral position switch 24 is ON, If these conditions are satisfied, the ISCF / B condition is satisfied. However, the target idle speed N _o is set in advance as in the sixth diagram the temperature of the cooling water as a parameter, is calculated using a detection signal from a water temperature sensor 23.

When the ISCF / B condition is satisfied, the target idle speed N _o
Is set using the value obtained above (S3), then ISC valve 1
The basic control amount G _B for controlling the 8 duty solenoid is set (S4). This basic control amount G _B is preset using the water temperature as a parameter as shown in FIG. 7, and therefore is calculated using the detected water temperature.

Next, the rotation speed deviation ΔN = (N _e -N _o ) is calculated (S5),
Next, the F / B correction amount G _FB is the previous feedback correction amount G _FB.
Is calculated by G _FB = G _FB + ΔG _FB (S6) by adding the increment ΔG _FB calculated by the preset characteristic as shown in Fig.8, and then another correction amount G _C is calculated. Done (S
7). The other correction amount G _C is added to the correction amount according to the engine load when the cooling compressor and other engine loads are activated based on the signal from the start / stop switch 24 or the like.

Then, the final air amount G is calculated by the equation _{G = G B + G FB +} G C (S8), the driving pulse corresponding to a final air quantity G to the duty solenoid of the ISC valve 18 is output (S16), Then S
Move to 1.

On the other hand, as a result of the determination in S2, if the ISCF / B condition is not satisfied, it is determined in S9 whether or not the vehicle is in the deceleration state. This deceleration determination is made in the same manner as in the case of step S42 in FIG. As a result of the deceleration determination, if it is not in the deceleration state, S15
At, the final air amount G corresponding to the operating state (engine speed N _e and intake air amount or throttle opening) is set based on the arithmetic expression and the table, and the process proceeds from S15 to S16.

In the deceleration state as a result of the determination in S9, in S10, the flag FG indicating the abnormality of the relief valve 15 is read from the memory of the RAM and it is determined whether or not FG = 1. If FG = 0, the relief valve 15 is normal. Sometimes G _B = 0 and G _FB = 0 are set (S12, S1
3) Then, the predetermined dash pod air G _DP is set (S1
4), shift to S16.

Next, when FG = 1 (relief valve is abnormal) in the deceleration state, the process shifts from S10 to S11, and the final air amount G reaches the predetermined maximum value G _{max because the} ISC valve 18 is fully opened in S11. It is set and then shifts to S16.

Thus, when the relief valve 15 is abnormal with FG = 1 and the final air amount G is set to G _max during deceleration, and the ISC valve 18 is opened to the maximum opening, the blower 6B and the throttle valve 8 are connected. The supercharged air is supplied to the intake port 1 through the intake passage 2.

However, in this case, in order to prevent the engine speed N _e from increasing due to an increase in the intake air amount, a command signal for retarding the ignition timing by a predetermined angle is output to the ignition time control, and the ignition timing retard reduces the combustibility. The increase in the number of rotations shall be suppressed (see the time chart in FIG. 9).

As described above, in the above engine control device, the detection signal from the air flow meter 4 is used to detect the abnormal state of the relief valve 15, and when the relief valve 15 is in the abnormal state, the ISC valve 18 is maximized during deceleration. Open to allow the bypass passage 17 to be relieved to the downstream portion of the intake passage 2,
It is possible to reliably prevent supercharged air from being trapped between the blower 6B and the throttle valve 8.

In particular, in this control device, the air flow meter 4, the bypass passage 17 and the ISC valve 18, which are usually provided in the engine E, can be effectively used without adding sensors and other devices, and can be implemented only by the control software. Therefore, it can be implemented easily and economically.

As a means for detecting the abnormality of the relief valve 15, a pressure sensor for detecting the supercharging pressure in the intake passage 2 between the blower 6B and the throttle valve 8 can be used. Further, the present invention can be similarly applied to an engine provided with a supercharger driven by a crankshaft instead of the turbocharger 6, and can be applied to a rotary piston engine in substantially the same manner.

[Brief description of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is an overall configuration diagram of an engine with a supercharger, Fig. 2 is a sectional view of a relief valve,
FIG. 3 is a flow chart of abnormality detection control, FIG. 4 is an explanatory diagram of detection signals of the air flow meter, and FIG. 5 is a flow chart of idle speed control including supercharging air relief control,
FIG. 6 is a characteristic diagram of the target idle speed, FIG. 7 is a characteristic diagram of the basic control amount, FIG. 8 is a characteristic diagram of the F / B correction amount, and FIG. 9 is I.
It is a time chart such as SC valve opening. 2 ... Intake passage, 4 ... Air flow meter, 6 ... Turbocharger, 8 ... Throttle valve, 14 ... Relief passage, 15 ... Relief valve, 17 ... Bypass passage, 18 ... IS
C valve, 20 ... crank angle sensor, 21 ... throttle opening sensor, 22 ... idle switch, 24 ... neutral position switch, 30 ... control unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Takayuki Okano 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) Reference JP-A-63-186929 (JP, A) 21532 (JP, U) Actually opened 64-25426 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A throttle valve for an engine, comprising: an intake passage provided with a supercharger and a throttle valve in order from an upstream side thereof, and a relief passage bypassing the supercharger and a relief valve opening a relief passage at the time of deceleration. A bypass passage for bypassing the engine, an idle speed control valve interposed in the bypass passage, an abnormality detecting means for detecting an abnormality in the relief valve, a deceleration detecting means for detecting a deceleration state of the engine, and outputs of the both detecting means. Accordingly, the control device for the engine with a supercharger, comprising: a relief control means for increasing the opening degree of the idle speed control valve during deceleration when the relief valve is in an abnormal state.