JPH01340A - Engine abnormality detection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an abnormality detection device for an engine equipped with an electronically controlled fuel injection system (EGI).

(Problems to be solved by the prior art and the invention) Conventionally, engines equipped with electronically controlled fuel injection systems (EGI) have been equipped with the following steps to maintain the air-fuel ratio in an optimal state:
The basic fuel injection amount is determined from the function of the engine speed (N) and the intake air amount (Q), and various sensors (for example,
There is also a control means for determining the optimum fuel injection amount for the current operation by adding or multiplying a correction coefficient based on the output signal from the exhaust sensor, water temperature sensor). This is disclosed as a known technique in JP-A-59-183040.

By the way, in a gasoline engine or the like, the amount of intake air supplied to the combustion chamber is determined by a throttle valve installed in the middle of the intake pipe. Therefore, in general, when the throttle valve is fully opened, the amount of intake air is throttled.
The fuel discharged from the injector is also determined based on this throttled intake air ram 1 and is therefore limited. Also, reduction from accelerated driving.

When the vehicle shifts to high-speed driving, fuel is temporarily cut off.

However, for example, in the throttle valve itself, or in the intake pipe downstream of this throttle valve, or
If cracks occur in the vacuum hose connected to this intake pipe due to deterioration over time, the actual intake air amount measured by the above intake air amount sensor may be large even though the throttle valve is fully open, and the above From the control means,
The fuel injection amount during the current operation is determined based on this intake air amount, which may cause overrun or the like.

If the crack is in a relatively early stage, the overrun will not occur and the operation will not be significantly impaired; however, if the engine continues to be operated without being noticed, it will become increasingly difficult to control the engine speed. When the engine speed exceeds a certain high speed, the fuel is automatically cut off, but when the engine speed drops, fuel is injected again, so unless the key switch is turned off, the high speed will be maintained and the engine will be handled from an overrun state. I can't get it out.

[Object of the Invention] The present invention has been made in view of the above circumstances, and is intended to prevent an overrun by notifying the driver of the failure when cracks or damage occur in the intake pipe downstream of the throttle valve. The present invention also aims to provide an engine abnormality detection device that can improve driving safety.

[Means and effects for solving the problem] The engine abnormality detection device according to the present invention detects an intake air amount signal from an intake air amount sensor provided downstream of the throttle valve;
When the intake air amount signal from the intake air amount sensor inputted when the throttle is fully closed to the control means that calculates the basic fuel injection amount based on M based on the rotation speed signal from the rotation speed sensor indicates a set value or more. , a control section that outputs an abnormality signal to the warning drive means is provided.

[Embodiments of the invention] Hereinafter, the present invention will be described in detail with reference to the drawings.

The drawings show an embodiment of the present invention; FIG. 1 is a schematic diagram of an engine control system, FIG. 2 is a block diagram of a control means, and FIG. 3 is a flowchart of an abnormality detection operation.

Reference numeral 1 in FIG. 1 is an engine body, and a combustion chamber 2 of this engine body 1 faces a spark plug 4 connected to a distributor 3. Furthermore, an intake pipe 5 and an exhaust pipe 6 are communicated with the combustion chamber 2, respectively.

A throttle valve 7 is interposed on the upstream side of the intake pipe 5, an air chamber 8 is formed on the downstream side thereof, and further,
The injector 9 faces the downstream side thereof. on the other hand,
The exhaust pipe 6 is connected to a muffler (not shown) via a catalytic converter 10.

Further, reference numeral 11 denotes a control means, and on the input side of this control means 11, a signal TH from a throttle position sensor 12 that detects the opening/closing state of the throttle valve 7,
A signal Q from a pressure sensor 13, which is an example of an intake air amount sensor communicating with the air chamber 8, and a signal N from a rotation speed sensor 14 provided in the distributor 3.
etc. are each input.

The throttle position sensor 12 is provided with an idle contact that is turned on when the throttle valve is fully open, and a power contact that is turned on when the throttle valve is fully open.

On the other hand, on the output side of this control means 11, there is an igniter 15a attached to the ignition coil 15 connected to the distributor 3, and a wear means 17 such as a warning light disposed on an instrument panel (not shown).
is connected.

The control means 11 also includes an performance unit (ALU) 11a, a read-only memory (ROM) 18, and a read/write memory (ALU) 11a, which are connected to each other via a pass line.
RAM) 19 and central processing unit (CPtJ) 1
It is structured around lb.

The input side of the ALtJ11a is a digital analog (
An A/D) converter 20 and an input processing circuit 21 that also functions as waveform shaping are connected.

The input processing circuit 21 receives an engine rotational speed signal N1 from the rotational speed sensor 14 and a throttle open or full open signal TH from the throttle position sensor 12. Note that a sample and hold signal is input to the A/D converter 20.

Furthermore, the output no.j of the ΔLU11a of the control means 11
On the side, an ignition timing drive circuit 22 that outputs an operation signal to the igniter 15a, an injector drive circuit 23 that outputs a fuel injection signal to the injector 9, and the warning means 1.
7 is connected to a warning display drive circuit 24 which outputs an operation signal.

(Function) The control means 11 operates according to a program stored in the ROM 18.

That is, the voltage value from the pressure sensor 13 is
After being converted into a decimal value by the /D converter 20, it is stored as intake pressure data (-intake air amount data) Q in the RAM 19 at predetermined time intervals.

Further, the engine rotation speed signal outputted from the rotation speed sensor 14 at regular intervals is inputted to the input processing circuit 21, and its pulse interval is measured, and the pulse interval is measured.
After being converted in LtJ1'1a, it is stored in the RAM 19 as engine rotation speed data N at predetermined intervals.

Further, the signal output from the throttle position sensor 12, that is, the idle contact ON (throttle closed state rr3), the power contact ON (high load state), or both contacts 0FF (steady operation). is input to the input processing circuit 21, and is input to the ALU 11.
At step a, the state of the throttle valve 7 is determined, and the throttle opening data T is added to the RΔM19 at predetermined intervals.
Stored as H.

Then, each data Q, N, stored in the RAM 19,
Of TH, first, a basic fuel injection amount is determined from a function of intake pressure data Q and engine rotational speed data N by interpolation calculation with a basic fuel injection amount map stored in advance in the ROM 18. Then, this basic fuel injection amount is corrected using detection signals from each sensor (exhaust sensor, water temperature sensor, etc.) to determine the actual fuel injection amount, and the actual fuel injection amount is sent to the injector 9 via the injector drive circuit 23. Outputs fuel injection pulse. Then, the injector 9 is opened according to the pulse interval and injects a predetermined amount of fuel into the combustion chamber 2.

Further, from the throttle opening degree data TH and the intake air amount data Q stored in the RAM 19, the presence or absence of an abnormal state of the intake air amount is detected.

In other words, cracks occur or damage occurs in the intake pipe 5 immediately downstream of the throttle valve 7, or in the vacuum hose (not shown) connected immediately downstream of the throttle valve 7, or in the throttle valve 7 itself. In this case, air is sucked in from this portion, and the intake pressure measured by the pressure sensor 13 increases accordingly.

Then, when the CPU 11b turns on the idle contact, it outputs a warning signal to the warning display drive circuit 24 in accordance with the state of the crack, operates the warning means 17 such as a warning light, and, if necessary, is the injector drive circuit 23
outputs a fuel cut signal to close the injector 9.

The abnormality detection procedure by the control means 11 will be explained with reference to the flowchart of FIG.

First, in step 101, the fuel cut FLAG is set to "1".
If it is 11'', it is determined that the fuel has been cut and the abnormal state is maintained, and the routine jumps to END, leaving the routine.

On the other hand, if the fuel cut FLAG is "≠1", it is determined that the engine is in normal operation or in the early stages of cracking or damage, and the process proceeds to step 102.

In this step 102, it is determined whether the idle contact of the throttle position sensor 12 is ON, that is, whether the throttle valve 7 is fully open. If the idle contact is OFF, the throttle valve 7 is opened, it is determined that the operating state is steady or accelerated, and the routine is exited.

That is, when air is sucked in through the cracks or the like and the engine speed unexpectedly increases, the driver attempts to throttle the throttle valve 7 in order to lower the engine speed. Therefore, the opening in which the throttle valve 7 is opened is considered to be within the range in which the engine speed can be controlled.

If the throttle valve 7 is fully closed and the idle contact of the throttle position sensor 12 is ON, the process proceeds to step 103.

Then, from step 103 onwards, an abnormality in the amount of intake air is detected.

First, in step 103, it is determined whether the amount of intake air (-intake pressure) Qidl when the throttle valve 7 is fully closed is larger than the set intake air (intake pressure) QKPth.

This set intake air amount Q KPHI is set by correcting a reference value determined in advance through experiments etc. based on data from each sensor such as a water temperature sensor, and is set by correcting the reference value determined in advance through experiments etc. This is calculated by converting the upper limit value of the air amount into the idle rotation speed.

The above intake air (ilQidl is the above set intake air amount Q
If it is lower than KPHL, it is determined that it is possible to operate, and the process proceeds to step 107; if it is higher, it is determined that there is an abnormal state, and the process proceeds to step 104.

Then, in step 104, the fuel cut FLAG is set to "1", and in step 105, a fuel cut signal is output to the injector drive circuit 23, the injector 9 is closed, and the fuel is forcibly cut. At the same time, in step 106, a warning signal is output to the warning display drive circuit 24, and the warning means 17, such as a warning light disposed on an instrument panel (not shown), is turned off.
N Operate.

On the other hand, in step 107, the intake air amount Q i
It is determined whether dl is greater than the set intake air IIQ KPH2.

This intake air setting fiQ KPH2 indicates the maximum amount of intake air sufficient for idling, and is set by correcting the reference intake amount determined in advance through experiments etc. based on data from various sensors such as the water temperature sensor. has been done.

The above intake air ff1Qidl is the setting intake air 1i1QK
If it is lower than PH2, it is determined that the engine is in normal idling or deceleration operation, and the routine is removed.

In addition, intake air rP1. Qidl is the set intake air amount Q
If it is higher than KPH2, that is, Q KPth >Q
If idl>QKPH2, it is determined that although there is an abnormality, there is no problem with driving, and the process proceeds to step 106, where only the warning means 17 is turned on.

Typically, cracks and the like progress from minute damage to larger damage. Therefore, at the initial stage of cracking, the process always proceeds to step 107 and the forwarding means 17 is turned on.

Therefore, the driver can accurately grasp the abnormal state before the fuel cut.

Note that the present invention is not limited to the above-mentioned embodiments. For example, in a device that sucks air from a bypass passage of a throttle valve via an idle speed control valve (ISCV) during idling, the amount of intake air is lower than the set value. If the engine speed increases, a warning may be displayed and the idle speed control valve (ISCV) may be operated to throttle the intake air M during idling or deceleration operation.

[Effects of the Invention] As explained above, according to the present invention, the basic fuel is determined based on the intake air amount signal from the intake air amount sensor provided downstream of the throttle valve and the rotation speed signal from the rotation speed sensor. If the intake air amount signal from the intake air amount sensor that is input when the throttle is fully closed is greater than or equal to the set value, the control means that determines the injection rA base outputs an abnormality signal to warn the IJJ.
Since a control unit is provided that outputs an output to the engine, if a crack or damage occurs in the intake pipe downstream of the throttle valve, the driver is immediately alerted to the malfunction.

Therefore, the driver can appropriately deal with failures, and can also prevent overruns before they occur, thereby achieving excellent driving safety.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a schematic diagram of an engine control system, FIG. 2 is a block diagram of a control means, and FIG. 3 is a flowchart of an abnormality detection operation. 7... Throttle valve, 11... Control means, 13
...Intake air amount t? sensor, 14... rotation speed sensor,
17...Warning drive means, N...Engine speed signal, Q...Intake air amount signal, Qidl...Intake air amount signal (when the throttle is fully closed), QKP)it,
Q KPH2...setting 1 air.

Claims (1)

[Claims] When the throttle is fully closed, it is input to a control means that calculates a basic fuel injection amount based on an intake air amount signal from an intake air amount sensor provided on the downstream side of the throttle valve and a rotation speed signal from a rotation speed sensor. An abnormality detection device for an engine, characterized in that the engine abnormality detection device is provided with a control section that outputs an abnormality signal to a warning drive means when the intake air amount signal from the intake air amount sensor indicates a set value or more.