JPH0861133A - Accumulator fuel injection device and controlling method thereof - Google Patents

Abstract

PURPOSE: To accurately judge the content of a malfunction in response to the various abnormal condition generated in an accumulator fuel injection device. CONSTITUTION: A feed pump 6, a high-pressure pump 4, a common rail 1, injector control valves 3a-3f are provided in this order between a fuel tank 7 and injectors 2a-2f. The device is also provided with an engine speed sensor 14, an accelerator open degree sensor 15, return passages 21a, 21b, common rail pressure control valves 5a, 5b, common rail internal pressure sensor 11, 12, a fuel passage internal pressure sensor 13 and a controller 9, which judges abnormality of the common rail internal pressure sensors 11, 12, abnormality of the common rail pressure control valves 5a, 5b, abnormality of the high pressure valve 4 or the fuel leakage on the basis of the detected values of each sensor and which displays it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-accumulation fuel injection device which detects an abnormal portion when an abnormality occurs in the pressure-accumulation fuel injection device and performs backup in accordance with each abnormal state, and its It relates to a control method.

[0002]

2. Description of the Related Art As a conventional pressure-accumulation type fuel injection device for a diesel engine, one proposed in, for example, Japanese Patent Laid-Open No. 5-52146 is known. This device is a so-called feedback control system that corrects the basic control amount of the fuel discharge control valve so that the fuel pressure becomes the target fuel pressure, and calculates the target control amount for actually driving the fuel discharge control valve. When a fuel leak occurs in the fuel supply system, the correction amount increases as the fuel leak amount increases, and thus the target control amount of the discharge control valve increases. By determining the fuel leak from the value, a sensor for detecting the fuel leak is unnecessary.

When learning control is performed, even if the amount of fuel leaking from the gap of the sliding portion of the injector or pump greatly changes due to aging, or the property of fuel is different, these It is possible to avoid an error in the basic energization start timing due to the influence, and the feedback correction amount is always a small value. Therefore, when the amount of feedback correction amount becomes large, this is due to the amount of fuel to be discharged and the amount to be injected from the high pressure pump, such as fuel blowout due to looseness or cracks in the pipe, high pressure pump abnormality, injection valve abnormality, etc. It means that either of them is abnormal.

[0004]

According to the conventional pressure-accumulation fuel injection device for a diesel engine as described above, it may be abnormal when a problem occurs in the common rail pressure sensor, the injector, the solenoid valve, the high pressure pump, or the like. Detected,
There is a problem that it is not possible to determine in which part of them the abnormality has occurred. In addition, there is a problem that an appropriate backup corresponding to each abnormality cannot be performed.

In view of the above problems, the present invention provides a pressure-accumulation fuel injection device and a control method therefor capable of accurately determining the content of a failure in response to various abnormalities occurring in the pressure-accumulation fuel injection device. It is intended to be provided. Another object of the present invention is to provide a pressure-accumulation fuel injection device and a control method thereof that can perform appropriate backup according to the status of an abnormality that has occurred.

[0006]

A pressure-accumulation type fuel injection device for a diesel engine according to the present invention for achieving the above object includes a feed pump and a feed pump between a fuel tank and an injector for injecting fuel into a combustion chamber. A high-pressure pump for increasing the pressure of fuel supplied from the feed pump, a common rail for storing high-pressure fuel, and an injector control valve for adjusting the injection amount of high-pressure fuel in the common rail for injecting from the injector are provided in this order. An engine speed sensor that detects an engine speed, an accelerator opening sensor that detects an accelerator opening, a plurality of return passages that connect the fuel passage between the high-pressure pump and a common rail and the fuel tank, The common rail pressure control valve arranged in each of these return passages and the fuel pressure in the common rail are detected. And the pressure sensor number of the common rail,
A fuel passage internal pressure sensor for detecting the fuel pressure in the fuel passage between the feed pump and the high pressure pump; detection values of the engine speed sensor, accelerator opening sensor, common rail internal pressure sensor, and fuel passage internal pressure sensor. Based on the above, there is provided a controller for discriminating and displaying whether there is an abnormality in the common rail pressure sensor, an abnormality in the common rail pressure control valve, an abnormality in the high pressure pump, or a fuel leak.

Further, a pressure-accumulation type fuel injection device for a diesel engine according to the present invention for achieving the above-mentioned another object is provided between a fuel tank and an injector for injecting fuel into a combustion chamber.
A feed pump, a high-pressure pump for increasing the pressure of fuel supplied from the feed pump, a common rail for storing high-pressure fuel, and an injector control valve for adjusting the injection amount of high-pressure fuel in the common rail for injecting from the injector, A plurality of engine speed sensors for detecting the engine speed, an accelerator opening sensor for detecting the accelerator opening, a fuel passage between the high-pressure pump and a common rail, and the fuel tank are provided in this order. Return passages, common rail pressure control valves arranged in each of these return passages, a plurality of common rail pressure sensors for detecting fuel pressure in the common rail, and a fuel passage in the fuel passage between the feed pump and the high pressure pump. The fuel passage pressure sensor for detecting the fuel pressure, the engine speed sensor and the actuator Based on the detected value of the Le opening sensor and the common rail pressure sensor and the fuel passage pressure sensor, it is provided with a controller for controlling the injector control valve and the common rail pressure control valve.

A fuel temperature sensor for detecting the fuel temperature in the fuel passage between the feed pump and the high pressure pump is provided, or a safety valve is provided on the common rail and a return passage opened and closed by the safety valve is provided. It is preferable to provide it between this common rail and the fuel tank. Also, in the injector control valve,
It is preferable to connect a return passage for returning the overflow fuel to the fuel tank.

On the other hand, the control method of the pressure-accumulation type fuel injection device of the present invention for achieving the above object is such that a feed pump is provided between the fuel tank and the injector for injecting the fuel into the combustion chamber, and the feed pump supplies the fuel. A high-pressure pump for increasing the pressure of fuel, a common rail for storing high-pressure fuel, and an injector control valve for adjusting the injection amount of high-pressure fuel in the common rail for injecting from the injector,
A plurality of engine speed sensors for detecting the engine speed, an accelerator opening sensor for detecting the accelerator opening, a fuel passage between the high-pressure pump and a common rail, and the fuel tank are provided in this order. Return passages, common rail pressure control valves arranged in each of these return passages, a plurality of common rail pressure sensors for detecting fuel pressure in the common rail, and a fuel passage in the fuel passage between the feed pump and the high pressure pump. In a pressure-accumulation fuel injection device of a diesel engine equipped with a fuel passage pressure sensor for detecting fuel pressure, if the common rail pressure control valve energization time is out of a predetermined range, this energization time must be longer than the predetermined range. Check that the common rail pressure sensor is abnormal and check that this energization time is shorter than the specified range. After confirming the above, a step of determining whether the absolute value of the difference between the plurality of common rail internal pressure sensors is larger than a predetermined value and determining whether the common rail internal pressure sensor is abnormal or the injection system is abnormal. When it is determined that the injection system is abnormal, the step of determining that the high-pressure pump is abnormal when the detection value of the fuel passage internal pressure sensor is larger than a predetermined value, and the detection value of the fuel passage internal pressure sensor is predetermined. If the value is less than the value, the method is based on a program including a step of checking whether or not the abnormality flag of the common rail pressure sensor is turned on and determining whether the fuel is leaking or the common rail pressure control valve is abnormal.

Further, a control method of a pressure accumulating fuel injection device of the present invention for achieving the above-mentioned another object is to provide a feed pump between a fuel tank and an injector for injecting fuel into a combustion chamber, and the feed pump. A high-pressure pump for increasing the pressure of fuel supplied from the engine, a common rail for storing high-pressure fuel, and an injector control valve for adjusting the injection amount of high-pressure fuel in the common rail for injecting from the injector are provided in this order, and the engine is also provided. An engine speed sensor that detects a rotation speed, an accelerator opening sensor that detects an accelerator opening, a plurality of return passages that connect the fuel passage between the high-pressure pump and a common rail and the fuel tank, and these A common rail pressure control valve arranged in each return passage and a plurality of commons for detecting the fuel pressure in the common rail. In the fuel injection device of the diesel engine, which is provided with a fuel pressure sensor in the fuel passage between the feed pump and the high-pressure pump, a plurality of common rail pressure sensors Check if the sensor abnormality flag is turned on, and if at least one of them is determined to be abnormal, the detection value of the common rail pressure sensor for which the abnormality flag is off is set to a predetermined value. It judges whether it is within the range.If it is within the predetermined range, the abnormality flag is turned off.Control is performed based on the detection value of the common rail pressure sensor. There is a program to judge that the common rail pressure sensor is abnormal and stop the feedback control, and to control based on the backup control map. It is a method.

Further, in order to achieve another object, the control method of the pressure-accumulation type fuel injection device of the present invention includes a feed pump between the fuel tank and the injector for injecting the fuel into the combustion chamber, and the feed pump. A high-pressure pump for increasing the pressure of supplied fuel, a common rail for storing high-pressure fuel, and an injector control valve for adjusting the injection amount of high-pressure fuel in the common rail for injecting from the injector,
A plurality of engine speed sensors for detecting the engine speed, an accelerator opening sensor for detecting the accelerator opening, a fuel passage between the high-pressure pump and a common rail, and the fuel tank are provided in this order. Return passages, common rail pressure control valves arranged in each of these return passages, a plurality of common rail pressure sensors for detecting fuel pressure in the common rail, and a fuel passage in the fuel passage between the feed pump and the high pressure pump. In a pressure-accumulation fuel injection device for a diesel engine provided with a fuel passage pressure sensor for detecting fuel pressure, it is confirmed whether or not the abnormality flag of the common rail pressure control valve is turned on, and if it is determined that abnormality has occurred, Shuts off the power supply to the abnormal common rail pressure control valve, and when the backup common rail pressure control valve is powered on. It is a method that has a program for determining the.

It is preferable that the target injection pressure is read from the control map stored in the ROM and set based on the detection values of the engine speed sensor and the accelerator opening sensor. The energization time of the common rail pressure control valve is It is preferable to perform control based on comparison between the common rail actual pressure calculated based on the detection value of the common rail internal pressure sensor and the target injection pressure set by reading from the control map stored in the ROM.

Further, the energization time of the injector control valve is based on the detected value of the engine speed sensor and the detected value of the accelerator opening sensor, the target injection amount read from the control map stored in the ROM, and the common rail. It is preferable to control based on the common rail actual pressure calculated based on the detection value of the internal pressure sensor.

[0014]

[Operation] Since the pressure-accumulation fuel injection device and the control method thereof according to the present invention have the above-mentioned configuration, the common rail actual pressure approaches the target injection pressure based on the detection values of the engine speed sensor and the accelerator opening sensor. As described above, the energization time to the common rail pressure control valve is controlled, and when the energization time is out of the upper limit of the predetermined range, the controller can determine that the common rail pressure sensor is abnormal and display it.

Further, when the energization time is out of the lower limit of the predetermined range, the absolute value of the difference between the detection values of the plurality of common rail pressure sensors is determined by the controller.
It is possible to judge whether or not it is larger than a predetermined value, and if it is larger than the predetermined value, it can be judged and displayed as an abnormality of the common rail pressure sensor, and if it is smaller than the predetermined value, it can be judged as an abnormality of the injection system. Then, if the detected value of the fuel passage internal pressure sensor is larger than a predetermined value, it can be judged and displayed as an abnormality of the high-pressure pump, and conversely, the detected value of the fuel passage internal pressure sensor can be displayed. Is below a predetermined value, check whether the abnormality flag of the common rail pressure sensor is on, and if it is on, fuel leak,
If it is off, it can be determined that the common rail pressure control valve is abnormal.

Explaining these abnormality determination methods in detail, first, for the abnormality of the pressure sensor in the common rail, a plurality of pressure sensors are provided in the common rail, and normally, the average value is controlled as a true pressure value, and at the same time, each pressure is measured. When the variation amount of the detected value of the sensor is obtained and the variation amount exceeding the preset predetermined variation amount is detected, it is determined that at least one of the plurality of pressure sensors has become abnormal.

Next, it is necessary to identify the abnormal pressure sensor, and the method is as follows. That is, when the engine speed and the accelerator opening are determined in the common rail, the fuel injection amount and the fuel injection pressure are controlled to be constant correspondingly, and at the same time, the discharge capacity of the high-pressure pump is also controlled to be constant. The open / close time ratio of is also constant. However, when the opening time of the common rail pressure control valve becomes longer than the normal state, it means that the fuel injection amount is smaller than the predetermined amount for some reason or the pressure sensor is detected higher than normal. ,in this case,
It can be concluded that the one showing the highest value among the pressure sensors is abnormal. Further, when the opening time of the common rail pressure control valve becomes shorter than the normal state, it can be concluded that the one showing the lowest value is abnormal.

On the other hand, in order to determine the abnormality of the high-pressure pump, a fuel passage pressure sensor is provided between the high-pressure pump and the feed pump that sucks the fuel from the fuel tank and supplies it to the high-pressure pump. The pressure on the primary side (upstream side) of the high-pressure pump is determined by the pressure-feeding capacity of the feed pump and the pressure-feeding capacity of the high-pressure pump.
If the engine speed and accelerator opening are determined, it will be a constant value. Therefore, the pressure value in the normal state determined by the engine speed and the accelerator opening is stored as a map in the storage device of the controller in advance, and the pressure value detected by the pressure sensor is set to the map to some extent. When a high pressure value is detected exceeding the allowable error of, it can be determined that the discharge capacity of the high-pressure pump has deteriorated.

When a fuel temperature sensor for detecting the fuel temperature in the fuel passage between the feed pump and the high-pressure pump is provided, it is possible to compensate for the expansion caused by the increase in the fuel temperature. Therefore, there is an advantage that the fuel injection amount becomes more accurate. Also, not only the display of abnormalities,
When performing backup control, it is checked whether or not the abnormality flags of the plurality of common rail pressure sensors are turned on, and if at least one of them is determined to be abnormal, the abnormality flag is set. It is determined whether the detected value of the common rail internal pressure sensor that is off is within the predetermined range, and if it is within the predetermined range, the abnormality flag is based on the detected value of the common rail internal pressure sensor that is off. If it is outside the predetermined range, it is judged that all the pressure sensors in the common rail are abnormal, the feedback control is stopped, and the control can be performed based on the backup control map. it can.

Explaining this backup, first, when all the common rail pressure sensors become abnormal, in order to control the fuel injection amount, the fuel injection pressure is always kept constant regardless of at least the engine operating condition.
In order to create this situation, the common rail pressure control valve is forcibly closed and fuel is continuously pumped. In addition, the common rail will be equipped with a mechanical safety valve that opens at the maximum pressure + α during normal control. As a result, the fuel pressure becomes the valve opening pressure of this safety valve, and a certain degree of accuracy is guaranteed. This backup prevents the fuel injection control from being completely disabled, and enables self-propelled operation to a repairable place.

Further, a plurality of common rail pressure control valves are provided,
Check whether the abnormality flag of the common rail pressure control valve that is normally used is turned on, and if it is determined to be abnormal, shut off the power supply to the common rail pressure control valve and control the common rail pressure for backup. The valve can be switched to control and its energization time can be determined.

[0022]

Embodiments of the present invention will now be described with reference to the drawings. First, FIG. 1 shows an outline of a pressure-accumulation type fuel injection device for a diesel engine of the present embodiment. Fuel in a fuel tank 7 is sucked up by a feed pump 6 and sent to a high pressure pump 4. In the high-pressure pump 4, the fuel sent from the feed pump 6 is further increased in pressure and sent to the common rail 1, and the high-pressure fuel in the common rail 1 has injector control valves 3a to 3f (usually solenoid valves are used). By controlling the valve opening timing and the valve opening time of, the fuel is injected from the six injectors 2a to 2f corresponding to each cylinder.

A safety valve 8 is provided to regulate the upper limit of the pressure inside the common rail 1. The safety valve 8 is provided.
A return passage 21 connects the fuel tank 7 and the fuel tank 7. Further, the return passage 21 is also extended and connected to each of the injector control valves 3a to 3f (in the figure, only the injector control valve 3a is connected for simplification),
The fuel overflowing from each injector control valve 3a to 3f is returned to the fuel tank 7. Further, the high pressure fuel passage 22 between the high pressure pump 4 and the common rail 1 also has 2
Book return passages 21a and 21b are connected, and these return passages 21 join the return passage 21 and communicate with the fuel tank 7. The common rail pressure control valves 5a, 21b are respectively provided in the two return passages 21a, 21b.
5b (usually using a solenoid valve) is provided.

On the other hand, each of the above injector control valves
The controller (ECU) 9 for controlling the opening and closing of the common rail pressure control valves 5a, 5b and 3a to 3f includes a signal line connected to various sensors (not shown) for detecting the status of the diesel engine and the pressure accumulating fuel injection device. Are connected.
That is, the common rail 1 is provided with two common rail internal pressure sensors 11 and 12 for detecting the internal pressure (fuel pressure) of the common rail 1.
11 and 12 are connected to the ECU 9 via pressure signal lines 11a and 12b.
It is connected to the. A similar fuel passage pressure sensor 13 is also provided in the fuel supply passage 22a between the feed pump 6 and the high pressure pump 4, and this pressure sensor 13 is also connected to the ECU 9 via the pressure signal line 13a. There is.

Further, a fuel temperature sensor 16 is provided in the fuel supply passage 22a and is connected to the ECU 9 via a temperature signal line 16a. Further, the diesel engine is provided with an accelerator opening sensor 15 for detecting an accelerator opening to obtain a load and an engine speed sensor 14 for detecting a rotation speed, and these detection signals are also output from the ECU 9
It is designed to be input to.

Then, as described above, the control signals are sent to the injector control valves 3a to 3f and the common rail pressure control valves 5a and 5b via the control valve drive signal lines 30a to 30f, 50a and 50b, respectively. It controls opening and closing. Further, when the abnormality of the pressure accumulating fuel injection device is detected, the ECU 9
The display is controlled so that any one of the pressure sensor abnormality lamp 17, the common rail pressure control valve abnormality lamp 18, the high pressure pump abnormality lamp 19, and the fuel leak lamp 20 are turned on.

Next, the control contents of the ECU 9 are shown in FIG.
~ It demonstrates based on the flowchart shown in FIG. First, in a normal state, in step S1 shown in FIG. 4, the engine speed sensor 14 detects the engine speed Ne, and then in step S2, the accelerator opening sensor 15 detects the accelerator opening _VL . Then, in step S3, the target injection pressure P _I of the common rail 1 is read from the predetermined pressure map (see FIG. 2) stored in the ROM in the ECU 9 based on Ne and V _L.

Next, in step S4, the pressure sensor 1
It is determined whether or not the abnormality flags 1 and 12 are turned on. If YES, the process proceeds to step S14, which will be described later, and NO.
If so, the process proceeds to step S5. In step S5, the pressures Pi ₁ and Pi ₂ of the common rail 1 are detected by the pressure sensors 11 and 12, and subsequently, in step S6, the average value of these pressures Pi ₁ and Pi ₂ is used as the actual pressure of the common rail 1 based on the detected values Pi ₁ and Pi _2. Pi =
It is calculated as (Pi ₁ + Pi ₂ ) / 2.

Next, in step S7, it is confirmed whether or not the abnormality flag of the common rail pressure control valve 5a is turned on. If YES, the process proceeds to step S20 described later, and if NO, the process proceeds to step S8. In step S8, the energization time of the common rail pressure control valve 5a (the opening time of the return passage 21a) T is determined so that the common rail actual pressure Pi becomes the target injection pressure P _I (PID control: proportional / integral / derivative control). .

In step S9, the energization time T of the common rail pressure control valve 5a or 5b determined in step S8 or step S20 described later falls within a predetermined range (To _{MIN to} To _MAX ) given in the map in the ROM. It is confirmed whether or not there is, and if YES, the process proceeds to step S10 (see FIG. 5), and if NO, step S21 of the abnormal mode described later.
(See FIG. 6).

Next, in step S10 shown in FIG.
Based on e and V _L , the target injection amount Q is read from the map (see FIG. 3) in the ROM. In step S11, the target injection amount Q, the common rail actual pressure Pi (≈P _I or P described later)
Based on the i _SAFE), calculates the energization time T _D of the injector control valve 3a to 3f. In step S12, the injection timing T _INJ is read from the map in the ROM based on Ne and V _L. Then, in step S13, the injector control valves 3a to 3f are energized (fuel injection) for a time T _D from the injection timing T _INJ, and the process returns to step S1.

Next, FIG. 4 shows the control contents when an abnormality occurs.
Let's go back and explain. First, in step S14 (when YES is determined in step S4), the detection value Pi ₁ (or Pi ₂ ) of the pressure sensor 11 (or 12) whose abnormality flag is off is within a predetermined range ( P _{MIN to} P _MAX )
Check if it is inside, and if YES, the pressure sensor
11 (or 12) is judged to be normal, and the process proceeds to step S15,
If NO, it is judged that both pressure sensors 11 and 12 are abnormal,
The process proceeds to step S16 described below.

In step S15, the detected value Pi of the pressure sensor 11 (or 12) determined to be normal in step S14
₁ (or Pi ₂ ) is set as the actual pressure Pi of the common rail 1 and the process proceeds to step S7. On the other hand, in step S16 (when NO is determined in step S14), both pressure sensors 11 and 12 are determined to be abnormal.
The abnormality flags of both pressure sensors 11 and 12 are turned on, and the pressure sensor abnormality lamp 17 is turned on. Then, step S1
At 7, the power supply to the common rail pressure control valves 5a and 5b is cut off, and the feedback control of the common rail pressure is stopped.

Then, in step S18, the actual pressure P of the common rail 1 is replaced with the feedback control.
i is set to the valve opening pressure Pi _SAFE of the safety valve 8, and step S
The map of the target injection amount Q is switched to the emergency map at 19 and the process returns to step S10. However, step S19 may be omitted. On the other hand, the above step S20 (step S
In case it is determined as YES) at 7, while blocking the power supply to the common rail pressure control valve 5a, as the common rail actual pressure Pi becomes equal to the target injection pressure P _I, the common rail pressure control valve 5b conduction time of the backup (Return passage 21
b open time) T is determined (PID control).

Next, referring to FIG. 6, in step S9, N
A program at the time of abnormality when it is determined to be O will be described. First, in step S21, the energization time T is To
Check if it is larger than _MAX (T> To _MAX )
If ES, it is determined that the pressure sensor 11 or 12 is abnormal, and the process proceeds to step S22. If NO, step S26 described later.
Go to.

[0036] In step S22, the difference between the detected value Pi ₂ detected value Pi ₁ and the pressure sensor 12 of the pressure sensor 11 .DELTA.Pi (= P
i ₁ −Pi ₂ ) is calculated. In the next step S23, ΔP
Check whether i is greater than 0 (ΔPi> 0), and
If ES, the process proceeds to step S24, and if NO, the process proceeds to step S25 described later. When the process proceeds to step S24, it is determined that the pressure sensor 11 is abnormal, the abnormality flag of the pressure sensor 11 is turned on, the pressure sensor abnormality lamp 17 is turned on, and the process proceeds to step S10. On the other hand, step S25
When it proceeds to, it is determined that the pressure sensor 12 is abnormal, the abnormality flag of the pressure sensor 12 is turned on, and it is preferable that the pressure sensor abnormality lamp 17 (an abnormality lamp corresponding to each pressure sensor is independently provided). ) Is lit, and step S1
Go to 0.

Further, the above-mentioned step S26 (step S
21), the absolute value of the difference between the detection value Pi ₁ of the pressure sensor 11 and the detection value Pi ₂ of the pressure sensor 12 | ΔP
Calculate i |. In the next step S27, | ΔPi |
Is greater than a predetermined value Po (| ΔPi |> Po)
If YES, it is determined that the pressure sensor 11 or 12 is abnormal, and the process proceeds to step S28. If NO, the pressure sensor 1
It is determined that there is an abnormality in the injection system other than 1 and 12, and the process proceeds to step S30 described later.

[0038] At step S28, the difference between the detected value Pi ₂ detected value Pi ₁ and the pressure sensor 12 of the pressure sensor 11 .DELTA.Pi (= P
i ₁ −Pi ₂ ) is calculated. Then, in the next step S29, it is confirmed whether or not .DELTA.Pi is larger than 0 (.DELTA.P
i> 0), if YES, then go to step S25 above,
If NO, the process proceeds to step S24. In step S30 shown in FIG. 7 (when NO is determined in step S27), the primary pressure Pi _{3 of the} high-pressure pump 4 is determined by the pressure sensor 13.
Is detected, and in the next step S31, it is confirmed whether or not this Pi ₃ is larger than a predetermined value P ₁₃ (Pi ₃ > P ₁₃ ).
If S, it is determined that the high-pressure pump 4 is abnormal, and step S32 is performed.
If NO, the process proceeds to step S33, which will be described later.

In step S32, the high-pressure pump abnormality lamp 19 is turned on, the process proceeds to step S10 described above, and in step S33 (when NO is determined in step S31), the abnormality flags of the common rail pressure control valves 5a and 5b are turned on. If YES, step S3
If NO, the process proceeds to step S35. In step S34, it is determined that there is a fuel leak in the common rail 1, the injectors 2a to 2f, or the fuel supply pipe connecting these, and the fuel leak lamp 20 is turned on, and all controls are stopped to stop the engine, Ends.

On the other hand, the above-mentioned step S35 (step S
If NO in 33), the abnormality flags of the common rail pressure control valves 5a and 5b are turned on, the common rail pressure control valve abnormality lamp 18 is turned on, and the process proceeds to step S10. Next, a second embodiment of the present invention will be described based on the flowcharts shown in FIGS. The following programs 1 and 2 are processed in parallel, and the program 3 is interrupted at an arbitrary cycle time for control.

First, the program 1 will be described with reference to the flowchart of FIG. In step S1 and step S2, the engine speed Ne and the accelerator opening _VL are detected and read from the engine speed sensor 14 and the accelerator opening sensor 15, respectively. Next, in step S3, the target injection pressure P _I of the common rail 1 is read from the map in the ROM based on Ne and V _L.

In the next step S4, the pressure sensor 11
Alternatively, it is confirmed whether or not the abnormality flag 12 is turned on. If YES, the process proceeds to step S14 described later, and if NO, the process proceeds to step S5. In step S5, the pressures Pi ₁ and Pi ₂ of the common rail 1 are detected and read by the pressure sensors 11 and 12. Then, in step S6, Pi ₁ , P i
The actual pressure Pi (average value) of the common rail 1 is calculated based on i ₂ .

In step S7, the common rail pressure control valve
Check if the abnormal flag of 5a is turned on, and
If ES, the process proceeds to step S20, and if NO, the process proceeds to step S8 to control the energization time T of the common rail pressure control valve 5a, and returns to step S1. Further, if the procedure advances to step S20, as well as to cut off the power supply to the common rail pressure control valve 5a, as the common rail actual pressure Pi becomes equal to the target injection pressure P _I, the common rail pressure control valve 5b conduction time of the backup Determine T (PID control).

On the other hand, if the process proceeds to step S14,
Pressure sensor 11 (or the one whose abnormality flag is off)
12) Detection value Pi₁(Or Pi₂) Is a predetermined range (To_MIN~
To _MAX) Inside, and if YES, pressure
It is determined that the sensor 11 (or 12) is normal, and the process proceeds to step S15.
If NO, the process proceeds to step S16. Step S1
In 5, the pressure sensor determined to be normal in step S14
11 (or 12) detection value Pi₁(Or Pi₂) To the common rail
The actual pressure Pi is set and the operation proceeds to step S7.

On the other hand, in step S16, the pressure sensor 1
Both 1 and 12 are determined to be abnormal, the abnormality flags of both pressure sensors 11 and 12 are turned on, and the pressure sensor abnormality lamp 17 is turned on. Then, in step S17, the common rail pressure control valves 5a and 5b are de-energized, and the common rail pressure feedback control is stopped. In the next step S18, the common rail actual pressure Pi is set to the valve opening pressure Pi of the safety valve 8.
Set as _SAFE and return. However, step S19 may be provided after that, and the map of the target injection amount Q may be switched to the emergency map in step S19, and then the process may return.

Next, the program 2 will be described with reference to the flowchart of FIG. First, in steps 1 and 2,
From the engine speed sensor 14 and the accelerator opening sensor 15,
The engine speed Ne and the accelerator opening _VL are detected and read respectively. In the next step S10, the target injection amount Q is read from the map in the ROM based on Ne and V _L.

In step S11, the pressure sensors 11 and 12 are
ON (YES)
In the case of, the target injection amount Q and the valve opening pressure Pi of the safety valve 8
From _SAFE, it calculates the energization time T _D of the injector 2a to 2f, when off (NO), the target injection amount Q and the common rail actual pressure Pi, calculates the energization time T _D of the injector 2a to 2f.

In step S12, the injection timing T _INJ is read from the map in the ROM based on Ne and V _L ,
In the next step S13, the time T _D from the injection timing T _INJ
Energize injector control valves 3a-3f only
Fuel is injected from 2a to 2f, and the process returns to step S1. The programs 1 and 2 described above are processed in parallel to perform normal control, and the next program 3 shown in FIGS. 10 to 12 is interrupted at an arbitrary cycle time to perform control at the time of abnormality.

First, in step S0 shown in FIG.
The energization time T of the rail pressure control valve 5a or 5b is detected. Next
In step S21 of, the energization time T is the upper limit value of the control range.
To _MAXGreater than or equal to (T> To_MAX)confirm
If YES, it is judged that the pressure sensor 11 or 12 is abnormal,
If the process proceeds to mode 1 and the result is NO, the energization time T is within the control range.
Lower limit value To_MINIs smaller than (T <To_MIN)
Confirm and proceed to mode 2 if YES or step 2 if NO
Return to step S0.

[0050] In the case of the mode 1 shown in FIG. 11 first proceeds to step S22, the difference ΔPi between the detection value Pi ₂ detected value Pi ₁ and the pressure sensor 12 of the pressure sensor 11 (= Pi ₁ -Pi ₂₎ To calculate. In step S23, it is confirmed whether or not .DELTA.Pi is greater than 0 (.DELTA.Pi> 0). If YES, the process proceeds to step S24, the abnormality flag of the pressure sensor 11 is turned on, and the pressure sensor abnormality lamp 17 is turned on. If NO, the process proceeds to step S25, the abnormality flag of the pressure sensor 12 is turned on, the pressure sensor abnormality lamp 17 is turned on, and the process returns.

[0051] In the case of the mode 2 shown in FIG. 12, first in step S26, the absolute value of the difference between the detection value Pi ₂ detected value Pi ₁ and the pressure sensor 12 of the pressure sensor 11 | ΔPi | (= | P
i ₁ −Pi ₂ |) is calculated. Next, in step S27,
Whether │ΔPi│ is larger than a predetermined value Po (│ΔPi
│> Po) and if YES, pressure sensor 11 or 12
Of the pressure sensors 11 and 12 is determined to be abnormal, and the process proceeds to step S30 described later.

[0052] At step S28, the difference between the detected value Pi ₂ detected value Pi ₁ and the pressure sensor 12 of the pressure sensor 11 .DELTA.Pi (= P
i ₁ −Pi ₂ ) is calculated. Then, in the next step S29, it is confirmed whether or not .DELTA.Pi is larger than 0 (.DELTA.P
i> 0), the process proceeds to step S25 if YES, conversely the process proceeds to step S24 if NO. On the other hand, if the process proceeds to step S30, the primary pressure Pi ₃ of the high-pressure pump 4 is detected by the pressure sensor 13, and this Pi ₃ is detected at the next step S31.
Is larger than a predetermined value P ₁₃ (Pi ₃ > P ₁₃ ), and if YES, it is judged that the high-pressure pump 4 is abnormal, the process proceeds to step S 32, the high-pressure pump abnormal lamp 19 is turned on, and the process returns. . If NO, the process proceeds to step S33 to check whether the abnormality flag of the common rail pressure control valve 5a is turned on, and if YES, the process proceeds to step S34, NO.
If so, the process proceeds to step S35.

In the case of step S34, it is judged that there is a fuel leak in the common rail 1, the injectors 2a to 2f, or the fuel supply pipe connecting these, and the fuel leak lamp 20 is turned on, and all controls are stopped. Stop the engine,
The program ends. On the other hand, in the case of step S35, the abnormality flag of the common rail pressure control valve 5a is turned on,
The common rail pressure control valve error lamp 18 is turned on and the process returns.

[0054]

The pressure-accumulation type fuel injection device for a diesel engine of the present invention has the above-mentioned configuration, and the common rail actual pressure approaches the target injection pressure based on the detection values of the engine speed sensor and the accelerator opening sensor. The control of the energization time to the common rail pressure control valve is performed as described above, and if this energization time deviates from the upper limit of the predetermined range, the controller
It is possible to judge and display the abnormality of the pressure sensor in the common rail.

When the energized time is out of the lower limit of the predetermined range, the absolute value of the difference between the detected values of the plurality of common rail pressure sensors is determined by the controller.
It is possible to judge whether or not it is larger than a predetermined value, and if it is larger than the predetermined value, it can be judged and displayed as an abnormality of the common rail pressure sensor, and if it is smaller than the predetermined value, it can be judged as an abnormality of the injection system. Then, if the detected value of the fuel passage internal pressure sensor is larger than a predetermined value, it can be judged and displayed as an abnormality of the high-pressure pump, and conversely, the detected value of the fuel passage internal pressure sensor can be displayed. Is below a predetermined value, check whether the abnormality flag of the common rail pressure sensor is on, and if it is on, fuel leak,
If it is off, it can be determined that the common rail pressure control valve is abnormal.

Therefore, it is possible to determine whether there is an abnormality in the common rail pressure sensor, an abnormality in the common rail pressure control valve, an abnormality in the high pressure pump, or a fuel leak. It can be displayed so that the type of abnormality can be known. When performing backup control as well as displaying the abnormality, it is confirmed whether or not the abnormality flags of the plurality of common rail pressure sensors are turned on, and at least one of them is abnormal. If it is determined that the abnormality flag is off, it is determined whether the detected value of the common rail pressure sensor is within the predetermined range. If it is within the predetermined range, the abnormality flag is off. Control can be performed based on the detection value of the common rail pressure sensor, and if it is outside the specified range, it is judged that all the common rail pressure sensors are abnormal, feedback control is stopped, and backup It can be controlled based on the control map.

Further, a plurality of common rail pressure control valves are provided,
Check whether the abnormality flag of the common rail pressure control valve that is normally used is turned on, and if it is determined to be abnormal, shut off the power supply to the common rail pressure control valve and control the common rail pressure for backup. The valve can be switched to control and its energization time can be determined.

In addition, when an abnormality occurs, the most suitable backup can be performed according to the type of abnormality. Therefore, except when the engine must be stopped (fuel leakage), self-propelling is performed. can do.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a pressure-accumulation fuel injection device of the present invention.

FIG. 2 is an engine speed-accelerator opening degree map stored in a ROM incorporated in the controller of the pressure-accumulation fuel injection device of the present invention.

FIG. 3 is an engine speed-fuel injection amount map stored in a ROM incorporated in the controller of the pressure-accumulation fuel injection device of the present invention.

FIG. 4 is a part of a flowchart in the first embodiment of the control method for the pressure accumulation type fuel injection device of the present invention.

FIG. 5 is a part of a flowchart in the first embodiment of the control method for the pressure accumulation type fuel injection device of the present invention.

FIG. 6 is a part of a flowchart in the first embodiment of the control method for the pressure accumulation type fuel injection device of the present invention.

FIG. 7 is a part of a flowchart in the first embodiment of the control method for the pressure accumulation type fuel injection device of the present invention.

FIG. 8 is a part of a flowchart in a second embodiment of the control method for the pressure accumulation type fuel injection device of the present invention.

FIG. 9 is a part of a flowchart in a second embodiment of the control method of the pressure accumulation type fuel injection device of the present invention.

FIG. 10 is a part of a flowchart in a second embodiment of the control method for the pressure accumulation type fuel injection device of the present invention.

FIG. 11 is a part of a flowchart in a second embodiment of the control method for the pressure accumulation type fuel injection device of the present invention.

FIG. 12 is a part of a flowchart in a second embodiment of the control method for the pressure accumulation type fuel injection device of the present invention.

[Explanation of symbols]

1 common rail 2a injector 2b injector 2c injector 2d injector 2e injector 2f injector 3a injector control valve 3b injector control valve 3c injector control valve 3d injector control valve 3e injector control valve 3f injector control valve 4 high pressure pump 5a common rail pressure control valve 5b common rail pressure control Valve 6 Feed pump 7 Fuel tank 8 Safety valve 9 Controller (ECU) 11 Common rail internal pressure sensor 12 Common rail internal pressure sensor 13 Fuel passage internal pressure sensor 14 Accelerator position sensor 15 Engine speed sensor 17 Pressure sensor error lamp 18 Common rail pressure control valve Error lamp 19 High-pressure pump failure lamp 20 Fuel leak lamp 21 Return passage 21a Return passage 21b Return passage

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location F02M 51/00 F 55/02 350 P 63/00 C

Claims (11)

[Claims] 1. A feed pump between a fuel tank and an injector for injecting fuel into the combustion chamber, a high-pressure pump for increasing the pressure of fuel supplied from the feed pump, and a common rail for storing high-pressure fuel. An injector control valve that adjusts the injection amount of high-pressure fuel in a common rail that is injected from the injector is provided in this order, and an engine speed sensor that detects an engine speed, and an accelerator opening sensor that detects an accelerator opening. A plurality of return passages connecting a fuel passage between the high-pressure pump and a common rail and the fuel tank, a common rail pressure control valve arranged in each of the return passages, and a plurality of fuel pressure detecting elements in the common rail. Common rail pressure sensor, and the fuel in the fuel passage between the feed pump and the high pressure pump. Based on the detection values of the fuel passage internal pressure sensor that detects the fuel pressure, the engine speed sensor, the accelerator opening sensor, the common rail internal pressure sensor, and the fuel passage internal pressure sensor, whether the common rail internal pressure sensor is abnormal or common rail A pressure-accumulation fuel injection device provided with a controller for discriminating and displaying whether the pressure control valve is abnormal, the high-pressure pump is abnormal, or a fuel leak. 2. A feed pump between a fuel tank and an injector for injecting fuel into the combustion chamber, a high-pressure pump for increasing the pressure of fuel supplied from the feed pump, and a common rail for storing high-pressure fuel. An injector control valve that adjusts the injection amount of high-pressure fuel in a common rail that is injected from the injector is provided in this order, and an engine speed sensor that detects an engine speed, and an accelerator opening sensor that detects an accelerator opening. A plurality of return passages connecting a fuel passage between the high-pressure pump and a common rail and the fuel tank, a common rail pressure control valve arranged in each of the return passages, and a plurality of fuel pressure detecting elements in the common rail. Common rail pressure sensor, and the fuel in the fuel passage between the feed pump and the high pressure pump. Based on the detection values of the fuel passage pressure sensor for detecting the fuel pressure, the engine speed sensor, the accelerator opening sensor, the common rail pressure sensor, and the fuel passage pressure sensor, the injector control valve and the common rail pressure control valve are set. An accumulator fuel injection device provided with a controller for controlling. 3. The pressure-accumulation fuel injection device according to claim 1, further comprising a fuel temperature sensor for detecting a fuel temperature in a fuel passage between the feed pump and the high pressure pump. . 4. The safety valve is provided on the common rail, and a return passage opened and closed by the safety valve is provided between the common rail and the fuel tank. Accumulation type fuel injection device. 5. The pressure-accumulation fuel injection device according to claim 1, wherein a return passage for returning overflow fuel to the fuel tank is connected to the injector control valve. 6. A feed pump between a fuel tank and an injector for injecting fuel into the combustion chamber, a high-pressure pump for increasing the pressure of fuel supplied from the feed pump, and a common rail for storing high-pressure fuel. An injector control valve that adjusts the injection amount of high-pressure fuel in a common rail that is injected from the injector is provided in this order, and an engine speed sensor that detects an engine speed, and an accelerator opening sensor that detects an accelerator opening. A plurality of return passages connecting a fuel passage between the high-pressure pump and a common rail and the fuel tank, a common rail pressure control valve arranged in each of the return passages, and a plurality of fuel pressure detecting elements in the common rail. Common rail pressure sensor, and the fuel in the fuel passage between the feed pump and the high pressure pump. In a pressure-accumulation fuel injection device for a diesel engine equipped with a fuel passage pressure sensor that detects the fuel pressure, if the common rail pressure control valve energization time deviates from the specified range, this energization time must be longer than the specified range. After confirming that the common rail pressure sensor is abnormal, and confirming that this energization time is shorter than the predetermined range, the absolute value of the difference between the common rail pressure sensors is less than the predetermined value. A step of determining whether the pressure is larger than the common rail internal pressure sensor or the injection system is abnormal, and a detection value of the fuel passage internal pressure sensor is a predetermined value when the injection system is abnormal. If it is larger than the above, it is determined that the high pressure pump is abnormal,
When the detected value of the fuel passage internal pressure sensor is less than or equal to a predetermined value, it is checked whether the abnormality flag of the common rail internal pressure sensor is on, and it is determined whether the fuel is leaking or the common rail pressure control valve is abnormal. A method for controlling an accumulator fuel injection device based on a program having a step of performing. 7. A feed pump between a fuel tank and an injector for injecting fuel into the combustion chamber, a high-pressure pump for increasing the pressure of fuel supplied from the feed pump, and a common rail for storing high-pressure fuel. An injector control valve that adjusts the injection amount of high-pressure fuel in a common rail that is injected from the injector is provided in this order, and an engine speed sensor that detects an engine speed, and an accelerator opening sensor that detects an accelerator opening. A plurality of return passages connecting a fuel passage between the high-pressure pump and a common rail and the fuel tank, a common rail pressure control valve arranged in each of the return passages, and a plurality of fuel pressure detecting elements in the common rail. Common rail pressure sensor, and the fuel in the fuel passage between the feed pump and the high pressure pump. In a pressure-accumulation type fuel injection device for a diesel engine provided with a fuel passage internal pressure sensor for detecting the fuel pressure, it is confirmed whether or not an abnormality flag of the plurality of common rail internal pressure sensors is turned on, and at least one of them is selected. When it is determined that the individual pieces are abnormal, the abnormality flag is off.It is determined whether the detected value of the common rail pressure sensor is within the predetermined range. If it is within the predetermined range, the abnormality flag is detected. Is off, control is performed based on the detection value of the common rail pressure sensor, and if it is outside the specified range, it is judged that all common rail pressure sensors are abnormal, feedback control is stopped, and backup is performed. Control method for a pressure-accumulation fuel injection device having a program for performing control based on a control map for a vehicle. 8. A feed pump between a fuel tank and an injector for injecting fuel into the combustion chamber, a high-pressure pump for increasing the pressure of fuel supplied from the feed pump, and a common rail for storing high-pressure fuel. An injector control valve that adjusts the injection amount of high-pressure fuel in a common rail that is injected from the injector is provided in this order, and an engine speed sensor that detects an engine speed, and an accelerator opening sensor that detects an accelerator opening. A plurality of return passages connecting a fuel passage between the high-pressure pump and a common rail and the fuel tank, a common rail pressure control valve arranged in each of the return passages, and a plurality of fuel pressure detecting elements in the common rail. Common rail pressure sensor, and the fuel in the fuel passage between the feed pump and the high pressure pump. In a pressure-accumulation fuel injection device of a diesel engine provided with a fuel passage pressure sensor for detecting the fuel pressure, it is confirmed whether or not an abnormality flag of the common rail pressure control valve is turned on, and if it is determined that an abnormality has occurred, Is a control method for a pressure-accumulation fuel injection device, which has a program that cuts off energization of an abnormal common rail pressure control valve and determines an energization time of a backup common rail pressure control valve. 9. The target injection pressure is read from a control map stored in a ROM and set based on the detection values of the engine speed sensor and the accelerator opening sensor. A method for controlling a pressure-accumulation fuel injection device according to any one of 1. 10. The energization time of the common rail pressure control valve includes a common rail actual pressure calculated based on a detection value of a common rail internal pressure sensor, and a target injection pressure set by reading from a control map stored in ROM. 9. The control method for the pressure-accumulation type fuel injection device according to claim 6, wherein the control method is performed based on the comparison of FIG. 11. The energization time of the injector control valve is
Based on the detection value of the engine speed sensor and the detection value of the accelerator opening sensor, the target injection amount read from the control map stored in the ROM, and the common rail actual value calculated based on the detection value of the common rail pressure sensor The method for controlling the pressure-accumulation fuel injection device according to claim 6, wherein the method is controlled based on the pressure.