JPH0575906B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fuel injection system for an internal combustion engine, and more particularly, the present invention relates to a fuel injection system for an internal combustion engine, and more particularly, a signal indicating the position of a fuel adjustment member drives an actuator that drives the fuel adjustment member. This invention relates to an electronically controlled fuel injection device that receives feedback from a control system.

Prior Art This type of conventional electronic fuel injection device calculates the optimal fuel injection amount at any given time according to information indicating the operating state of the engine, such as the engine speed, accelerator position, etc. The position of the fuel adjustment member is controlled so that the difference between the target fuel adjustment member position required to obtain the desired injection amount and the actual fuel adjustment member position becomes zero. Therefore, a sensor is provided that outputs a signal indicating the position of the fuel adjustment member, and this signal is fed back to form a closed loop control system. When a failure occurred, control became completely impossible, and engine operation had to be stopped. However, the reliability of the system is significantly impaired if the engine operation has to be stopped simply due to a failure of the sensor that detects the position of the fuel adjustment member. Particularly in the case of equipment for vehicles, if the engine becomes completely unable to operate, it is extremely inconvenient as it makes it impossible to move by one's own power. In some cases, there is a risk that an accident may occur that threatens the lives of the passengers.

For this reason, we have proposed a device that is configured to change the return path of the control system and continue controlling the injection amount by using the engine rotation reference as the feedback signal in the event that any of the above-mentioned sensors malfunctions. (Utility Model Application Publication No. 57-53040). However, if the return route is switched as described above while the vehicle is running,
Due to sudden changes in torque, etc., sudden deceleration, sudden acceleration, etc. suddenly occur, resulting in a problem that drivability deteriorates.

OBJECT OF THE INVENTION Accordingly, an object of the present invention is to stop the operation of the engine once a failure occurs in the sensor that detects the position of the fuel adjustment member, and then, if desired, to stop the operation of the engine using the signal from the sensor. It is an object of the present invention to provide an electronic fuel injection device that can stably perform fuel injection without any fuel injection.

Configuration of the Invention The configuration of the present invention includes a fuel injection pump for injecting and supplying fuel to an internal combustion engine, a means for outputting a reference pulse every time a crankshaft of the internal combustion engine reaches a predetermined reference rotation position, and a fuel injection pump for supplying fuel to an internal combustion engine. The apparatus includes a position sensor that outputs a position signal indicative of the position of a fuel adjustment member of the injection pump, and is responsive to at least the reference pulse and the position signal to obtain a desired target injection amount depending on the current operating state of the internal combustion engine. an electronically controlled fuel comprising: a servo control unit that outputs a servo signal for positioning the fuel adjustment member; and a drive unit that performs a positioning operation of the fuel adjustment member in response to the servo signal; In the injection device, a determining means for determining whether or not a failure has occurred in the servo control unit, and in response to a determination result of the determining unit, stopping operation of the internal combustion engine when a failure occurs in the servo control unit. means for outputting an accelerator signal indicating the amount of operation of the accelerator operating member; and calculating means for calculating a control target position of the fuel regulating member in response to the accelerator signal and the reference pulse. , means for releasing the stopped state of the internal combustion engine in response to turning on of a start switch when the determining means determines that a failure has occurred in the servo control section, and the servo signal The present invention is characterized in that it is provided with means capable of supplying a signal indicating the calculation result in the calculation means to the drive section instead of the calculation means.

According to the above configuration, if any failure occurs in the servo control section, the operation of the internal combustion engine is temporarily stopped, an appropriate failure display is displayed to inform the driver of the occurrence of a failure, and the start switch is then turned on. If set to , the engine can be released from the stopped state. In conjunction with this release operation, the position of the fuel adjustment member can be controlled by open-loop control, and thereby the internal combustion engine can be continuously controlled. Therefore, in the case of a vehicle internal combustion engine, even if the servo control section fails, the vehicle can be moved by itself.

Furthermore, since the failure display continues even when the position of the fuel adjustment member is controlled by open-loop control, it is possible to make the driver aware that emergency operation is occurring, which is extremely desirable from a safety standpoint. .

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to illustrated examples.

FIG. 1 shows a block diagram of an embodiment of an electronically controlled fuel injection system according to the present invention.
The fuel injection device 1 electronically controls the position of a control sleeve (not shown), which is a fuel adjustment member of the fuel injection pump 2, and adjusts the fuel supplied to the diesel engine 4 to a required value commensurate with its operating state. This is a device for controlling the In order to calculate the optimum fuel injection amount according to the operating conditions between aircraft at that time, accelerator data A indicating the operation amount of the accelerator pedal 6, speed data N indicating the rotation speed of the diesel engine 4, and boost of the diesel engine 4 are used. A first calculation unit 5 is provided to which boost pressure data 9 indicating the pressure is input. Accelerator data A is output from an accelerator sensor 7 that converts the operation amount of the accelerator pedal 6 into an electrical signal. In order to obtain the speed data N, a TDC sensor 8 is installed on the crankshaft of the diesel engine 4 to output a top dead center pulse TDC at the rotation angle position of the crankshaft when the cylinder piston of the diesel engine 4 reaches the top dead center. is installed, and by calculating the period of this top dead center pulse TDC with the speed calculator 9, speed data N indicating the rotational speed of the diesel engine 4 at any given moment is outputted from the speed calculator 9.

The calculation result calculated in the first calculation section 5 based on the above data A, N, P is the target injection amount.
It is output as data D ₁ indicating Q _t . data D ₁
is input to the converter 10, where the target injection amount
It is converted into target position data D ₂ indicating the target position R _t of the control sleeve necessary to obtain Q _t ,
The signals are input to the error detection section 11 and the failure determination section 12, respectively.

The error detection unit 11 receives data D ₃ indicating the current position R _a of the control sleeve from the position sensor 13 . The error detection unit 11 determines the target position of position R _a based on the data D ₂ and D ₃ .
The deviation from R _t is calculated, and the deviation ΔR (= R _t − R _a )
Data _D4 indicating this is output. Data D ₄ is PID
The data is input to the calculation unit 14 and subjected to data processing necessary for performing PID control, and as a result, the actuator 15 is controlled by PID so that the position R _a of the control sleeve matches the target position R _t based on the deviation ΔR.
PID control data _D5 for control is output.
The PID control data D ₅ is input to the drive circuit 17 via the changeover switch 16 , where it is converted into a control signal S ₁ , and this control signal S ₁ is applied to the actuator 15 .

In the above-mentioned servo control unit to which the data D ₃ output from the position sensor 13 is input as feedback data, closed loop control is performed so that the target injection amount Q _A calculated by the first calculation unit 5 is obtained. Data _D5 is output as the output of the servo control section.

Even if some abnormality occurs in this servo control unit and the above-mentioned servo control no longer operates normally,
A second calculation section 18 is provided so that the injection amount can be controlled as desired. Second
Accelerator data A, speed data N, and top dead center pulse TDC are input to the calculation unit 18, and a target injection amount for open loop control is calculated according to the accelerator data A and speed data N. Then, data indicating the position of the control sleeve required to obtain the injection amount according to this calculation result is output as preliminary control data _D6 . The above-mentioned calculation in the second calculation unit 18 is performed by storing data in accordance with predetermined speed regulating characteristics for open-loop control in the memory in advance, and then calculating data according to the contents of each data A and N at that time. The control sleeve can be read out from the memory as data indicating the control target position of the control sleeve. Second calculation unit 18
The above-mentioned calculation in is configured to be performed in synchronization with the generation timing of the top dead center pulse TDC. Calculation of preliminary control data D ₆ is top dead center pulse
When executed in synchronization with the timing of TDC occurrence,
Since the preliminary control data _D6 can be obtained while the operating conditions of the diesel engine 4 are always the same, the diesel engine 4 can be stably controlled using the preliminary control data _D6 .

The preliminary control data D ₆ obtained in this way is
When the data is input to the changeover switch 16 and it is determined that some kind of failure has occurred in the servo control unit as will be described later, data D ₆ is applied to the drive circuit 17 in place of data D ₅ .

In order to determine whether there is a failure in the servo control section, a failure determination section 12 to which data D ₂ and D ₃ are input is provided. The failure determination unit 12 determines whether or not the difference between the target position R _t of the control sleeve and the actual position _Ra continues to be greater than or equal to a predetermined value for a predetermined period of time based on the data D _{2 and} D 3 . Based on the result of this determination, it is determined whether or not some kind of failure has occurred in the servo control section. In other words, if the difference remains at a predetermined value or higher for a predetermined period of time or more, it is determined that some kind of failure has occurred in the servo control section, and in other cases, the servo control section does not operate normally. It is determined that there is. A determination signal _S2 indicating the determination result is output from the failure determination section 12 and input to the switch control section 23 and the display 24, respectively.

When the discrimination signal _S2 indicates a failure in the servo control section, the display 24 displays the occurrence of the failure using appropriate means such as a lamp or a buzzer. The switch control unit 23 is for controlling the switching of the changeover switch 16 and for controlling the fuel cut electromagnetic valve 25, which is provided in the fuel injection pump 2 and performs fuel supply and stop control, on and off. The control unit 23 operates in response to a starting signal ST and a discrimination signal _S2 that are output when a starting switch 26 for starting the diesel engine 4 is turned on.

The switch control section 23 closes the fuel cut solenoid valve 25 to cut off the fuel when the discrimination signal _S2 indicates that a failure has occurred in the servo control section while the engine is running. i.e. starting signal
In the state where ST is output, the discrimination signal S ₂
indicates the occurrence of a fault, the selector switch 16 is switched from the state shown by the solid line to the state shown by the dotted line, and the fuel cut solenoid valve 2 is switched.
5 is opened and the start signal ST is being output, if the content of the discrimination signal _S2 indicates that the servo control etc. is normal, the changeover switch 16 is opened.
With fuel cut solenoid valve 2 switched as shown by the solid line,
A control signal S ₃ for controlling the opening and closing of the fuel cut electromagnetic valve 25 and a control signal S ₄ for controlling the changeover switch 16 are output so as to open the fuel cut solenoid valve 25 .

According to such a configuration, when the failure determination unit 8 determines that some kind of failure has occurred in the servo control unit during operation of the diesel engine 4, the fuel cut solenoid valve 25 is closed and the diesel engine 4 is stopped from operating. It will be in a stopped state. At this time, the occurrence of the fault is displayed on the display 24, so the driver can immediately know that the fault has occurred, and the diesel engine 4
Necessary measures can be taken immediately by stopping the operation of the equipment.

After the operation of the diesel engine 4 has been stopped in this way, when the start switch 26 is turned on, the fuel cut solenoid valve 25 is opened by the control signal _S3 from the switch control section 23, and at this time, the changeover switch 16 is turned on. It is switched by the signal _S4 as shown by the dotted line. Therefore, instead of data D ₅ , data D ₆ is supplied to the drive circuit 17 and the second calculation unit 1
The position of the control sleeve is controlled by open-loop control so that the speed regulating characteristic is achieved based on the control calculation in step 8. During each of the above control operations,
When the rotational speed of the diesel engine 4 becomes equal to or higher than the predetermined upper limit rotational speed _Nnax , the diesel engine 4
In order to stop the operation of the engine, it is equipped with a speed determination section 27 into which data _D6 indicating the value of the rotational speed N _nax and speed data N are input, and when N>N _nax , the fuel cut electromagnetic A control signal S ₅ for closing the valve 25 is output from the speed determining section 27 . Therefore, if the engine speed increases abnormally for some reason during the control operation based on the data _D5 or _D6 , the speed determination section 27 will stop the fuel supply to the diesel engine 4 to ensure the safety of the engine. It is possible to ensure safe driving.

As mentioned above, in this device, if a failure occurs in the servo control section, it switches to open loop control according to data D ₆ , so in the case of an internal combustion engine device for a vehicle, for example, the vehicle can be safely operated by itself. You can move it to any location. In this case as well, the display 24 displays a message indicating that the vehicle is in emergency operation mode, which can draw the driver's attention and is useful for safe driving.

2 and 3 show flowcharts of a control program in the case where the portion of the control system of the apparatus shown in FIG. 1, surrounded by a chain line, is constructed using a microcomputer.

To explain the control program with reference to FIG. 2, after starting the program, first step 3 is executed.
1, initialization is performed and each flag F _E , F _ST
is reset, and the counter CTR is also reset to zero. Next, data such as data A, N, and P are read (step 32), and it is determined whether the flag _FE is "1" (step 33). Flag F _E is a flag that is set to "1" when some abnormality occurs in the servo control system, and in this case, flag F _E is "0".
It is becoming. Next, in step 34, a target injection amount Q _t is calculated based on the data N, A, and P, and this calculation result Q _t is converted into a corresponding target sleeve position R _t (step 35), and the converted data is converted into data. It is output as _D2 (step 36).

Next, data D ₃ is read (step 37), a deviation ΔR is calculated based on data D ₂ and D ₃ (step 38), and it is determined whether ΔR is smaller than a predetermined value A ( Step 39). ΔR<
In the case of A, the value of the counter CTR is reset to zero (step 40), and the process returns to step 32.

If ΔR≧A, 1 is added to the contents of the counter CTR (step 41), and the counter CTR is
A determination is made as to whether or not the value is greater than a predetermined value B (step 42). If the value of the counter CTR is less than or equal to B, the process returns to step 32, but CTR>
If B is selected, the program proceeds to step 43 and the flag F _E is set to "1". That is, if the state in which the value of ΔR is greater than the predetermined value A continues for a period of time indicated by the predetermined value B, the flag F _E is set to "1",
A message indicating that some kind of failure has occurred in the servo control unit is displayed, and the fuel cut solenoid valve 25 is closed (step 44).

When the flag _F becomes "1", the determination result in step 33 becomes YES, and in step 45 it is determined whether or not the start switch 26 is on. If the start switch 26 is off, the flag F is set in step 46. A determination is made as to whether _ST is "1" or not. The flag F _ST is a flag indicating whether or not the start switch 26 is turned on when the flag F _E is "1". Therefore, in this case the flag F _ST
is "0", and the process proceeds to step 44. Therefore, when it is detected that a fault has occurred in the servo control section, the fuel cut solenoid valve 25 is closed and the display 16 continues to display the occurrence of the fault until the start switch 26 is turned on. Become.

When the start switch 26 is turned on, step 4
The determination result in step 5 is YES, and the flag F _ST is “1”.
(step 47), and the fuel cut solenoid valve 25 is opened (step 48). After that,
The switch 16 is switched as shown by the dotted line in FIG. 1 to enter the emergency control mode (step 49).

If the determination result in step 46 is YES,
That is, when the start switch 26 is turned on while the flag F _E is "1", step 4 is executed.
8, the fuel cut solenoid valve 25 is opened and the emergency control mode is entered (step 49).

FIG. 3 shows a detailed flowchart of the program when the emergency control mode is entered.
To explain the flowchart of FIG. 3, first, in step 50, the switch 16 is switched as shown by the dotted line in FIG.

Next, speed data N and boost pressure data P
It is determined whether or not they are larger than predetermined maximum values _Nnax and _Pnax , respectively (steps 51 and 52), and if both of the determination results in steps 51 and 52 are NO, the steps shown in FIG. Return to 32.

If the determination result is YES in at least one of steps 51 and 52, the fuel cut solenoid valve 25 is closed (step 53).
As a result, the operation of diesel engine 4 is stopped,
Set _FST to "0" (step 61) and return to step 32 in FIG.

That is, if N>N _nax or P>P _nax , it is dangerous to continue operating the engine, so the engine operation is forcibly stopped.

When the top dead center pulse TDC is output, the interrupt program INT shown in FIG. 3 is executed. The interrupt program sets the flag in step 54.
Determine whether F _T is "1" or not. The flag F _T is used to determine whether or not a timer that operates in response to the top dead center pulse TDC is in operation in order to measure the period of the top dead center pulse TDC. F _T
= "0", it indicates that the timer is in a stopped state, and therefore, the timer is started in response to the input of the top dead center pulse TDC, and the flag F _T is set to "1" (step 55). ). If the determination result at step 54 is NO, the execution of this interrupt program is completed by executing only step 55, and the process returns to the control program shown in FIG. Note that the timer is still operating in this case, and when the interrupt program INT is executed in response to the occurrence of the next top dead center pulse TDC, in this case, the determination result at step 54 becomes YES. ,
At step 56, the timer is stopped and flag F _T is reset to "0". Therefore, the timing content of the timer indicates the time from when one top dead center pulse TDC is output until the next top dead center pulse TDC is output, and based on the timing content of this timer, the diesel engine Speed data N indicating the current rotational speed of 4 is calculated (step 5).
7), it is determined whether the flag F _E is "1" (step 58).

If the flag F _E is "0", the control program shown in Fig. 2 is returned after just calculating the data N, indicating that some kind of failure has occurred in the servo control section and the flag F _E is "1". If so, proceed to step 59 and enter the data for open loop control.
D ₆ operation is performed. Since the computation of the data _D6 has been explained in detail with reference to FIG. 1, the details of the computation will be omitted here. In this way, the calculation of data _D6 is based on the top dead center pulse TDC
is executed when D6 is output, and data _D6 is output at step 60. That is, the calculation of data _D6 is configured to be executed in synchronization with the generation of the top dead center pulse TDC, and is executed by open loop control of the control sleeve, which is executed when a failure occurs in the servo control section. Position control can be performed stably.

In the above embodiment, when some kind of failure occurs in the servo control section, the switch 16 is automatically switched as shown by the dotted line using the control signal _S4 , but the switch 16 can be switched manually if desired by the driver. It is also possible to have a configuration in which this is performed. In this case, if a failure occurs in the servo control section and the engine operation is stopped once, then if the switch 16 is switched as shown by the dotted line before turning on the start switch 26, the failure will occur. After that, when the engine is started, the position of the control sleeve can be controlled by open loop control.

Effects of the Invention According to the present invention, as described above, when any failure occurs in the servo control section, the operation of the diesel engine is temporarily stopped and a display indicating that the failure has occurred is displayed to the driver. can be informed. Then, when the start switch is turned on, the stopped state of the engine is released, and the engine can be operated in the emergency control mode if desired. Therefore, even if a failure occurs in the servo control section, the engine will not become inoperable, and the vehicle or the like will be able to move on its own. In addition, when operating in emergency mode, after the engine has stopped,
This is executed when the start switch is turned on by the driver, so unlike the case where the control mode is suddenly changed while the engine is running, it prevents the engine from suddenly accelerating or decelerating, and also displays failures. This makes it possible to drive safely, which is extremely desirable from a safety standpoint. Furthermore, since the operation in the emergency control mode is the control of the fuel adjustment member position by open loop control, control that is almost the same as normal control can be expected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one implementation of the present invention, and FIGS. 2 and 3 are flowcharts showing a program when a microcomputer executes some of the functions of the blocks shown in FIG. 1...Fuel injection device, 2...Fuel injection pump, 4...
Diesel engine, 5... First calculation unit, 6... Accelerator pedal, 8... TDC sensor, 9... Speed calculator, 1
2... Failure determination section, 13... Position sensor, 15... Actuator, 16... Changeover switch, 18... Second calculation section, 23... Switch control section, 24... Display, 25
...Fuel cut solenoid valve, 26...Start switch, D ₅ ,
_D6 ...data, N...speed data, A...accelerator data, _S2 ...discrimination signal, _S3 , _S4 ...control signal, ST...
Starting signal.

Claims (1)

[Claims] 1. A fuel injection pump for injecting and supplying fuel to an internal combustion engine, means for outputting a reference pulse every time the crankshaft of the internal combustion engine reaches a predetermined reference rotational position, and a position of a fuel adjustment member of the fuel injection pump. positioning of the fuel adjustment member so as to provide a desired target injection amount in response to at least the reference pulse and the position signal in accordance with the current operating state of the internal combustion engine; In an electronically controlled fuel injection device, the electronically controlled fuel injection device includes a servo control unit that outputs a servo signal for performing the servo control, and a drive unit that performs a positioning operation of the fuel adjustment member in response to the servo signal. determining means for determining whether or not a failure has occurred in the internal combustion engine; and means for stopping operation of the internal combustion engine and displaying a failure indication when a failure occurs in the servo control unit in response to the determination result of the determining means. , and a calculation means for calculating a control target position of the fuel adjustment member in response to the reference pulse;
means for releasing the stopped state of the internal combustion engine in response to turning on of a start switch when the determining means determines that a failure has occurred in the servo control section; A fuel injection device characterized by comprising means capable of supplying a signal indicating a calculation result of the calculation means to the drive section instead.