JPH11190247A - Engine fuel supply diagnostic device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To previously prevent erroneous judgement and to properly carry out fail-safe control by forbidding injector diagnosis in the case when detection timing is delayed by furnishing a means to detect that the timing detect a signal from an injector drive unit is delayed. SOLUTION: An injector 13 of an engine is controlled through an injector drive unit 50 by an injector driving pulse 51 from a control unit 15 to compute and process output signals of a crank angle sensor, an air flow meter, an acceleration sensor, etc., by inputting them. An opening valve electric current and a holding electric current are respectively input to the control unit 15 as diagnostic results 52, 53, and injector diagnosis is carried out by an injector diagnostic device 54. However, in the case when an injector diagnosis inhibiting factor such as timing to detect a signal from the drive unit 50 is delayed, etc., injector diagnosis by the injector diagnostic device 54 is forbidden.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine fuel supply and diagnosis device and a diagnosis method.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No. Hei 8-210168 discloses a fuel injection valve for injecting fuel into an intake system, an abnormality detecting means for detecting an operation abnormality of the fuel injection valve based on a voltage of a drive circuit, Abnormality processing means for performing an engine protection process or a warning process when an abnormal operation of a fuel injection valve is detected is described.

[0003] Japanese Patent Application Laid-Open No. Hei 8-170552 discloses an apparatus ECU for calculating an optimal drive duty from an engine speed and water temperature and controlling a solenoid valve with a plurality of coils.
In order to accurately detect the abnormality including the open destruction of the solenoid valve drive transistor in, the mutual induction generated between the coils is converted to a drive frequency or duty ratio that does not affect the abnormality detection, and the abnormality is compared with a comparator It is described to detect.

[0004]

There is a need for a diagnosis of an injector drive unit. The present invention investigates the cause of the erroneous determination of the diagnostic device in order to perform this diagnosis correctly,
For example, it is an object of the present invention to provide an engine fuel supply device in which injector diagnosis is immediately prohibited when a diagnosis timing is lost due to occurrence of a high-priority interrupt and a risk of erroneous determination occurs. Further, a diagnostic device and a diagnostic method used in the fuel supply device are provided.

[0005]

One of the causes of the erroneous determination by the diagnostic apparatus is that the processing is held by a higher priority interrupt task, and the pulse for diagnosis does not already exist at the time of processing, and "pulse exists""No" may be output. That is, one of the features of the present invention is to prohibit the diagnosis when there is an inappropriate diagnosis inhibiting factor for performing the diagnosis of the injector drive unit.
One example is to prohibit injector diagnosis if the timing is late.

[0006] In addition, even when the injector drive current has not reached the failure determination current, the injector diagnosis is not performed.

Further, when the engine is idling and at a high speed, or when a failure occurs in the control unit, the injector diagnosis is prohibited.

The present invention specifically provides the following apparatus and method.

Means for detecting operating conditions; means for calculating a fuel injection pulse width based on the operating state; means for detecting a signal from an injector drive unit (drive circuit); and based on a signal from the injector drive unit. In the engine fuel supply device having means for performing injector diagnosis, means for detecting that the timing of detecting a signal from the injector drive unit is delayed, and means for prohibiting the injector diagnosis when the timing is delayed. An engine fuel supply device comprising:

The injector diagnosis can be performed by reading a signal from the injector drive unit when a predetermined time has elapsed since the end of the injector injection.

The means for detecting that the timing of detecting the signal from the injector drive unit is delayed measures a predetermined time from the end of the injector injection and determines whether or not the predetermined time has elapsed. can do.

Means for detecting operating conditions; means for calculating a fuel injection pulse width based on the operating state; means for detecting a signal from the injector drive unit; and injector diagnosis based on a signal from the injector drive unit. An engine fuel supply device comprising: means for specifying the fuel injection pulse width; and means for prohibiting the injector diagnosis when the fuel injection pulse width is equal to or less than a predetermined value. Engine fuel supply.

Means for detecting operating conditions; means for calculating a fuel injection pulse width based on the operating state; means for detecting a signal from the injector drive unit; and performing injector diagnosis based on a signal from the injector drive unit. Means and a circuit for forcibly cutting a fuel injection pulse at idle and at high speeds, wherein the engine fuel for inhibiting the injector diagnosis at idle and at high speeds is provided. Feeding device.

Means for detecting operating conditions, a control unit for calculating a fuel injection pulse width based on the operating state, means for detecting a signal from the injector drive unit, and injector diagnosis based on a signal from the injector drive unit In the engine fuel supply device having means for performing, a control unit failure response circuit is provided in the control unit,
An engine fuel supply device comprising means for inhibiting the injector diagnosis based on a signal from the failure response circuit.

A switching element connected in series to an electromagnetic coil of the injector and connected in series to a power supply, and a capacitor branched and connected between the electromagnetic coil and the switching element are provided. Current detecting means for detecting a current when a valve opening voltage and a holding voltage of an injection voltage pulse supplied to the electromagnetic coil are supplied to the voltage diagnostic device of the injector driving device for supplying the energy to the electromagnetic coil of the injector; Pulse generating means for outputting the result of the output as a signal pulse, and diagnosis prohibiting means for prohibiting valve opening voltage diagnosis and holding voltage detection diagnosis when the read timing of the output pulse exceeds the pulse width. An injector diagnostic device composed of:

A switching element connected in series with an electromagnetic coil of the injector and connected in series to a power supply, and a capacitor branched and connected from between the electromagnetic coil and the switching element are provided. In the voltage diagnostic method of the injector driving device for supplying the discharged energy to the electromagnetic coil of the injector, the valve opening voltage and the holding voltage of the injection voltage pulse supplied to the electromagnetic coil are output as corresponding signals, respectively, and 500 μs after the end of injector injection Is an injector diagnostic method for inhibiting injector diagnostics using the signal pulse.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an engine system to which the present invention is applied. In the drawing, air to be taken in by an engine 1 is taken in from an inlet 4 of an air cleaner 3 and enters a collector 8 through a throttle valve device 7 provided with a throttle valve 6 for controlling the amount of intake air. The throttle valve 6 is
The throttle valve 6 is connected to the motor 10, and the throttle valve 6 is operated by driving the motor 10. By operating the throttle valve 6,
The intake air volume is controlled. The intake air reaching the collector 8 is distributed to each intake air pipe 19 connected to each cylinder 2 of the engine 1 and guided to the cylinder 2.

On the other hand, fuel such as gasoline is sucked and pressurized from a fuel tank 11 by a fuel pump 12, and then supplied to a fuel system 21 in which a fuel injection valve (injector) 13 and a variable fuel pressure regulator 14 are piped. Is done. The fuel system is adjusted to a predetermined pressure by the above-described variable fuel pressure regulator 14, and is injected into the cylinder 2 from the injector 13 having a fuel injection opening in each cylinder 2. Further, a signal representing the intake flow rate is output from the air flow meter 5 and input to the control unit 15.

Further, a throttle sensor 18 for detecting the opening of the throttle valve 6 is attached to the throttle valve device 7, and the output thereof is also input to the control unit 15.

Reference numeral 16 denotes a crank angle sensor which is driven to rotate by a camshaft 27 and outputs a signal indicating the rotational position of the crankshaft. This signal is also input to the control unit 15.

Reference numeral 20 denotes an A / F provided in the exhaust pipe 28.
An (air-fuel ratio) sensor detects and outputs the actual operating air-fuel ratio from the exhaust gas component, and the signal is input to the control unit 15 in the same manner.

Reference numeral 9 denotes an accelerator sensor provided integrally with the throttle valve device 7 and connected to an accelerator pedal 49. The accelerator sensor 49 detects and outputs the amount by which the driver operates the accelerator pedal 49, and outputs the signal to the control unit 15. Is input to

The control unit 15 has a processing means (CPU) 26 and receives as input signals signals from various sensors for detecting the operating state of the engine, such as the above-described crank angle signal and accelerator opening signal. ,
A predetermined operation is performed, and various control signals calculated as a result of the operation are output. A predetermined control signal is output to the injector 13, the ignition coil 17, and the motor 10 for operating the throttle valve, and the fuel supply is performed. Control, ignition timing control, and intake air amount control are executed.

A motor driver relay 31, a control unit relay 32, and an ignition switch 33 are provided between the power supply (battery) 30 and the control unit 15. Reference numeral 35 denotes a warning device including various warning lights.

Since these configurations are well known, no further description is required. A fuel pressure sensor 22 is provided adjacent to a variable fuel pressure regulator 14 provided in the fuel system.
Is provided, and the signal is input to the control unit 15.

FIG. 2 shows an engine fuel supply control device.

The processing means (CPU) 100 (indicated by 26 in FIG. 1) in the control unit 15 is a bus 10.
The bus 101 is connected to an input processing circuit 102 and an output processing circuit 103. The input processing circuit 102 includes a fuel pressure sensor 107 and an air flow sensor 10.
8, crank angle sensor 109, throttle sensor 11
0, the accelerator sensor 111, a water temperature sensor 112, O ₂ sensor 113, an ignition switch 114 (shown in FIG. 1 33.), The signal from the starter switch 115 and the battery voltage 116 is input. A processing signal from the input processing circuit 102 is input to the bus 101 and also to the interrupt controller 104. Timer 10
5, the required time is measured. The output signal from the output circuit 103 is supplied to the variable pressure regulator 117, the injector 118, the injector 119, the injector 120, the injector 121, the fuel pump 122,
It is output to an igniter 123 and a warning device 124 (indicated by 36 in FIG. 1). The signal recorded in the ROM 131 is input to the bus 101, and the signal from the bus 101 is
The data is output to the RAM 132 and the backup RAM 106 and recorded. These configurations are well known.
The CPU 100 includes a failure determination unit 135 described later.

FIG. 3 shows a block diagram for an embodiment of the present invention. The injector drive unit 50 is controlled by an injector drive pulse 51 from the control unit 15 and controls fuel injection to the injector 13. The valve opening current at this time is used as the diagnostic result 52 as
The holding current is signal-input to the control unit as a diagnosis result 53, and injector diagnosis is performed by an injector diagnosis device 54, which is one of the functions. 55 is a battery.

FIG. 4 shows the injector drive pulse, injector valve opening voltage,
The relationship between the injector holding voltage, the injector driving current including the valve opening current and the holding current, the injector lift, the signal of the valve opening current diagnosis result, and the signal of the holding current diagnosis result is shown in relation to time. In the normal state, it can be extracted as a one-shot signal as shown in the figure.

FIG. 5 is for explaining the necessity of the injector diagnosis, and shows data on the fuel injection amount, the fuel consumption, the engine torque, the exhaust emission, and the exhaust temperature at the time of normal operation and at the time of failure.

FIG. 6 is a block diagram showing an embodiment of the present invention. As shown in the figure, the signals from the battery voltage, the crank angle sensor, the air flow meter, the accelerator sensor, and the drive unit diagnostic signal line are input-processed 61 and used in the injector injection pulse width calculation 62. The calculation result is used for the injector drive control 63 and transmitted to the injector drive unit. Based on this result and the result of the input processing, a failure detection necessity determination and a hindrance factor determination 64 are made. Details of the failure necessity determination will be described later. A failure diagnosis 65 or a failure diagnosis prohibition 66 is performed based on the failure necessity determination. When a failure diagnosis 65 is made and a failure determination 67 is made, a fail-safe control 68 is performed,
The result is output to a warning light to issue a warning, and is used for the injector injection pulse width calculation 62.

The drive unit 50 supplies a high voltage, that is, a valve opening voltage, and a low voltage, that is, a holding voltage, to the injector. At this time, the current when the valve opening voltage and the holding voltage are supplied is detected by the current detecting means. The injector drive unit performs a diagnosis based on the current value, and sends a diagnosis result to the control unit 15 via a communication line. Based on this result, the control unit 15 makes a failure determination. This failure determination is prohibited in the following cases.

FIG. 7 shows the relationship between the injector pulse, the drive unit diagnostic communication line, and the timer. As shown in the figure, when there is a valve opening current or a holding current on the drive unit communication line, it appears as a low pulse signal. In the normal case, the detection timing is set at the set time point of the Low pulse from the end of the injector pulse, and the presence of each current signal is detected. This is point A71 when viewed from the timer. However, the detection timing is delayed by the interrupt operation of the higher priority operation, and the point B72 is detected.
In some cases.

FIG. 8 shows the relationship between the drive unit diagnostic communication line and the normal and fault reading values. The High signal output when there is an interrupt in the normal state and the High signal output in the case of a failure are the same, and the failure is diagnosed and determined at the time of the interruption. In such a case, the diagnosis is canceled.

FIG. 9 shows a flow chart for dealing with this case. It is determined whether an injector injection end interrupt has occurred (step 901), and a communication line detection timing is set (step 902). Next, it is determined whether or not the detection timing has been waited (step 903). If No, the communication line output value is read (step 905), and the injector drive unit diagnosis is performed (step 90).
6). If Yes, cancel the diagnosis (step 90
4).

FIG. 10 is a time chart showing another example in which the injector diagnosis is not performed. This figure shows the injector drive pulse for performing the operation of minimizing the required injection pulse width when the fuel is cut or the like, the injector valve opening voltage,
The injector holding voltage, injector driving current, injector lift amount, valve opening current diagnosis result signal, and holding current diagnosis result signal are displayed in relation to time. In this figure, when the required injection pulse width is extremely small, the injector drive current may be cleared before reaching the failure determination current. In such a case, the signal of the valve opening current diagnosis result and the signal of the holding current diagnosis result do not show a one-shot signal output even in a normal operation. For this reason, the one-shot signal is not detected, and there is a possibility that an erroneous determination of a failure may be made despite normal operation. Therefore, in such a case, the injector diagnosis must be prohibited. FIG. 11 shows a flow chart for dealing with this case. The injector injection pulse width T1 is calculated (step 1101), and it is determined whether T1 is smaller than a predetermined minimum value or T1 ≧ DUTIMIN (step 1102). Ye
In the case of s, drive unit diagnosis is permitted (step 1).
103), and read the communication line output value (step 11).
04), an injector drive unit diagnosis is performed (step 1105). If No, drive unit diagnosis is prohibited (step 1106).

FIG. 12 is a block diagram showing another example in which the injector diagnosis is not performed. The same components as those in FIG. 3 are denoted by the same reference numerals. The control unit outputs the injector drive pulse 56 during normal operation, but a circuit for forcibly cutting the fuel injection pulse during idling and high rotation, that is, the failure response circuit 57 does not output the injector drive pulse 51 during operation. Things happen. Therefore, the valve opening current diagnosis result 52 and the holding current diagnosis result 53 are not output from the injector drive unit 50. When the valve opening current diagnosis result 52 and the holding current diagnosis result 53 are not output, the control unit 15 determines whether the injector drive pulse 56 is normally output from the control unit. Take the drive unit diagnosis prohibition action.

FIG. 13 is a flowchart showing another example in which the injector diagnosis is not performed in the case of FIG. This example includes a means for detecting an operating condition, a means for calculating a fuel injection pulse width based on the operating state, a means for detecting a signal from an injector drive circuit, and an injector based on a signal from the injector drive circuit. In the engine fuel supply and diagnosis device including a means for performing diagnosis and a circuit for forcibly cutting a fuel injection pulse at idle and at high rotation, the injector diagnosis is prohibited at the time of idling and at high rotation. Is what you do.

In the figure, the engine speed MNRPM is calculated, and the idle-time switch SW is detected (step 1).
301). It is determined whether the idle switch SW is ON and whether the engine speed MNRPM is greater than a predetermined maximum speed DUNEMN (step 1302). If No, drive unit diagnosis is permitted (step 130).
3), and read the communication line output value (step 130)
4) Injector drive unit diagnosis is performed (step 1305). If Yes, the drive unit diagnosis is prohibited (step 1306).

[0041]

According to the present invention, when the following erroneous judgment is made in the injector diagnosis, the injector diagnosis prohibition process can be taken immediately, so that a warning is issued, for example, as shown in FIG. Fuel injection amount,
Corresponding measures can be taken to make the fuel consumption, engine torque, exhaust emission and exhaust temperature appropriate. That is, the fail-safe control can be appropriately performed as shown in FIG.

When the diagnostic timing is delayed due to the occurrence of a high-priority interrupt When the prohibition injection pulse width is reduced to a predetermined value or less When the engine is idling and rotating at a high speed When a failure occurs in the control unit

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an engine fuel supply control device.

FIG. 3 is a block diagram of an embodiment of the present invention.

FIG. 4 is a time chart showing timing for performing injector diagnosis.

FIG. 5 is an explanatory diagram showing the necessity of injector diagnosis.

FIG. 6 is a block diagram of an embodiment of the present invention.

FIG. 7 is a time chart showing timings at which injector diagnosis may be performed.

FIG. 8 is a diagram showing signal values.

FIG. 9 is a flowchart of the embodiment of the present invention.

FIG. 10 is a time chart showing the necessity of prohibiting injector diagnosis.

FIG. 11 is a flowchart of the embodiment of the present invention.

FIG. 12 is a block diagram of an embodiment of the present invention.

FIG. 13 is a flowchart of the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 13 ... Fuel injection valve (injector) 15
... Control unit, 17 ... Ignition coil, 20 ... A
/ F sensor, 26 processing unit, 33 ignition switch, 50 injector drive unit, 51
Injector drive pulse, 52 ... valve opening current diagnosis result, 5
3 ... holding current diagnosis result, 54 ... injector diagnosis device,
55 ... battery.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Hori 2520 Address Takaba, Hitachinaka City, Ibaraki Prefecture Within the Automotive Equipment Division of Hitachi, Ltd.

Claims (8)

[Claims] A means for detecting an operating condition; a means for calculating a fuel injection pulse width based on the operating state; a means for detecting a signal from an injector drive unit;
In an engine fuel supply device comprising means for performing injector diagnosis based on a signal from the injector drive unit, a means for detecting an impeding factor for detecting a signal from the injector drive unit; and Means for prohibiting injector diagnosis. 2. The engine fuel supply diagnostic device according to claim 1, wherein the injector diagnosis includes prohibiting reading of a signal from an injector drive unit when a predetermined time has elapsed from the end of injector injection. 3. The engine fuel supply according to claim 2, further comprising means for detecting a delay in detecting a signal from the injector drive unit to determine whether or not a predetermined time has elapsed. apparatus. 4. A means for detecting an operating condition, a means for calculating a fuel injection pulse width based on the operating state, a means for detecting a signal from an injector drive unit, and an injector diagnosis based on a signal from the injector drive unit. An engine fuel supply device comprising: means for specifying the fuel injection pulse width; and means for prohibiting the injector diagnosis when the fuel injection pulse width is equal to or less than a predetermined value. An engine fuel supply device characterized in that: 5. A means for detecting an operating condition, a means for calculating a fuel injection pulse width based on the operating state, a means for detecting a signal from an injector drive unit, and an injector diagnosis based on a signal from the injector drive unit. And an engine fuel supply provided with a circuit for forcibly cutting a fuel injection pulse during idling and high rotation. In the case of idling and high rotation, a means for inhibiting the injector diagnosis is provided. An engine fuel supply device characterized in that: 6. A means for detecting an operating condition, a control unit for calculating a fuel injection pulse width based on the operating state, a means for detecting a signal from an injector drive unit, and a signal based on a signal from the injector drive unit. An engine fuel supply device comprising means for performing injector diagnosis, wherein the control unit is provided with a control unit failure response circuit, and the control unit is provided with means for inhibiting the injector diagnosis based on a signal from the failure response circuit. An engine fuel supply device characterized by the following. 7. A switching element connected in series with an electromagnetic coil of an injector and connected in series to a power supply, and a capacitor branched and connected between the electromagnetic coil and the switching element. In a diagnostic device for an injector drive unit that supplies stored energy to an electromagnetic coil of an injector, current detection means for detecting a current when supplying a valve opening voltage and a holding voltage of an injection voltage pulse supplied to the electromagnetic coil; Pulse generating means for outputting the result as a signal pulse, and detection inhibiting means for inhibiting valve opening voltage detection and holding voltage detection when the read timing of the output pulse exceeds the pulse width. An injector diagnostic device, comprising: 8. A switching element connected in series with an electromagnetic coil of an injector and connected in series to a power supply, and a capacitor branched and connected between the electromagnetic coil and the switching element. A diagnostic device for an injector drive unit that supplies stored energy to an electromagnetic coil of an injector, wherein the valve opening voltage and the holding voltage of an injection voltage pulse supplied to the electromagnetic coil are output as corresponding signals, and 500 μs from the end of injector injection. An injector diagnostic method comprising prohibiting injector diagnostics using the corresponding signal pulse after a lapse of time.