JP3345933B2 - Accumulator type fuel injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply pump, in which fuel fed from a fuel supply pump is stored in a high pressure state in a pressure accumulating chamber (common rail), and the high pressure fuel is stored in a fuel injection valve provided in each cylinder of an internal combustion engine. More specifically, the present invention relates to an accumulator-type fuel injection device capable of detecting fuel leakage from the fuel supply system.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. Sho 62-2581
As disclosed in Japanese Patent Application Laid-Open No. 60-260, there is known an apparatus in which fuel fed from a fuel supply pump is temporarily stored in a common rail, and this is supplied to a diesel engine via a fuel injection valve. Further, in this type of accumulator type fuel injection device, since the fuel injection pressure from the fuel injection valve is determined by the fuel pressure in the common rail (common rail pressure), a pressure sensor for detecting the common rail pressure is provided, and the detected pressure is detected. The amount of fuel pumped from the fuel supply pump is controlled based on the common rail pressure.

As described above, in the device in which the high-pressure fuel is temporarily stored in the common rail, the fuel injection pressure can be controlled by the common rail pressure, and the fuel injection amount and the fuel injection timing are determined by the opening time and the opening timing of the fuel injection valve. Can be controlled respectively. Therefore, as compared with a general fuel injection device including a fuel injection pump and a nozzle, this type of device can perform more precise fuel injection control.

[0004]

However, in this type of fuel injection device, when an abnormality such as a pipe break occurs in the fuel supply system from the fuel supply pump to the fuel injection valve, the following problem occurs. I was In such a case,
The common rail pressure decreases due to fuel leakage. Therefore, in order to control the common rail pressure to a desired value, the amount of fuel pumped from the fuel supply pump must be increased. As a result, a vicious cycle may occur, in which the amount of fuel leakage further increases.

[0005] The applicant of the present invention has proposed a device capable of promptly detecting such a fuel leak in the fuel supply system without using a special sensor, as disclosed in Japanese Patent Application No. 3-97324. A device has been proposed in which fuel leakage is determined based on a control amount that determines the pumping amount. However, when the load of the diesel engine fluctuates, the target value of the common rail pressure (hereinafter referred to as target common rail pressure) also changes. Then, the control amount of the fuel supply pump also changes greatly, and it may not be possible to determine the fuel leakage. For this reason, during the operation of the diesel engine, it has not always been possible to detect fuel leakage.

[0006] The threshold value of the control amount used for determining fuel leakage varies depending on the rotational speed of the diesel engine. Because the fuel supply pump normally rotates in synchronization with the diesel engine, the correspondence between the control amount of the fuel supply pump and the fuel pumping amount changes depending on the rotation speed of the diesel engine. Therefore, even if the target common rail pressure and the fuel injection amount are the same, the threshold value of the control amount changes according to the rotation speed of the diesel engine. However, it is difficult to set a map for calculating the above-mentioned threshold value for every rotational speed of the diesel engine. Accordingly, it has not been easy to accurately detect fuel leakage at any rotational speed of a diesel engine.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an accumulator type fuel injection device capable of accurately detecting fuel leakage irrespective of engine load fluctuations and engine speed.

[0008]

SUMMARY OF THE INVENTION The present invention of claim 1, wherein has been made in order to achieve the above object, as illustrated in FIG. 8, the accumulator chamber storing fuel under high pressure, for each predetermined period < a fuel supply pump for pumping fuel into the accumulator , a fuel injection valve for injecting the high-pressure fuel stored in the accumulator into each cylinder of the internal combustion engine, and a fuel for detecting the fuel pressure in the accumulator Pressure detecting means, and the pressure detected by the fuel pressure detecting means.
Fuel pressure is set based on the operating state of the internal combustion engine.
Fuel supply pump so that it matches the target fuel pressure
The pumping amount of the pump to the pressure accumulating chamber in the predetermined cycle is controlled.
In the pressure accumulating type fuel injection device, during the operation of the internal combustion engine, the fuel supply pump supplies the fuel at every predetermined cycle.
Fuel pumping by the pumping amount of
Determination period detection means for detecting a predetermined determination period during which none of the fuel injection into each cylinder is performed; and fuel for calculating a change in fuel pressure in the accumulator chamber detected by the fuel pressure detection means during the determination period. Pressure change calculating means, and fuel leak determining means for determining fuel leak from a fuel supply system from the fuel supply pump to the fuel injection valve based on the calculated fuel pressure change. The gist of the present invention is a pressure accumulating fuel injection device. According to another aspect of the present invention, there is provided a pressure storage chamber for storing fuel in a high pressure state, a fuel supply pump for pumping fuel to the pressure storage chamber at predetermined intervals , and A fuel injection valve for injecting the stored high-pressure fuel into each cylinder of the internal combustion engine; and a fuel pressure detecting means for detecting a fuel pressure in the pressure accumulating chamber, wherein the fuel pressure detected by the fuel pressure detecting means is ,the above
Target fuel pressure set based on the operating state of the internal combustion engine
As match, before Symbol every predetermined cycle of the fuel supply pump
In the pressure- accumulation type fuel injection device in which the amount of pressure supplied to the pressure accumulating chamber is controlled , during operation of the internal combustion engine, the fuel supply pump is supplied to the pressure accumulating chamber by the amount of pressure supplied at the predetermined cycle . Determination period detection means for detecting a predetermined determination period during which neither the inflow of fuel nor the outflow of fuel from the pressure accumulation chamber is executed; and the accumulation chamber detected by the fuel pressure detection means during the determination period A fuel pressure change calculating means for calculating a change in fuel pressure; and a fuel leak determining means for determining fuel leak from a fuel supply system from the fuel supply pump to the fuel injection valve based on the calculated fuel pressure change. , Are provided.

[0009]

According to the first aspect of the present invention, the fuel pressure detected by the fuel pressure detecting means is controlled by the internal combustion engine.
It matches the target fuel pressure set based on the operating conditions.
As described above, the pumping amount of the fuel supply pump is controlled,
The supply pump pumps the above-mentioned pumping amount into the accumulator at predetermined intervals.
Then, the fuel injection valve injects the fuel stored in the accumulator into each cylinder. For this reason, the fuel pressure in the accumulator chamber detected by the fuel pressure detecting means increases when the fuel supply pump feeds the fuel, and decreases when the fuel injection valve injects the fuel. On the other hand, even during the operation of the internal combustion engine, there is a predetermined determination period during which neither fuel pumping nor fuel injection is performed. During this period, the fuel pressure in the accumulator is usually kept substantially constant.
Then, the fuel pressure during this determination period shows the above behavior regardless of the load fluctuation and the number of revolutions of the engine.

However, when fuel leaks from the fuel supply system from the fuel supply pump to the fuel injection valve, the fuel pressure in the accumulator drops significantly during the determination period. According to the present invention, the fuel pressure change in the accumulator chamber detected during the determination period is calculated, and the fuel leakage from the fuel supply system is determined based on the fuel pressure change. Regardless, fuel leakage can be accurately detected even during operation of the internal combustion engine. Further, according to the second aspect of the present invention, the fuel pressure detected by the fuel pressure detecting means is determined.
Target fuel whose pressure is set based on the operating state of the internal combustion engine
The pumping rate of the fuel supply pump is controlled to match the pressure.
The fuel supply pump is set up in the accumulator at regular intervals.
The fuel injection valve injects the fuel stored in the pressure accumulating chamber into each cylinder by pumping the pressure feeding amount . For this reason, the fuel pressure in the accumulator chamber detected by the fuel pressure detecting means increases when the fuel supply pump feeds the fuel, and decreases when the fuel injection valve injects the fuel. On the other hand, even during the operation of the internal combustion engine, there is a predetermined determination period during which neither the inflow of fuel into the accumulator or the outflow of fuel from the accumulator is performed. During this period, the fuel pressure in the accumulator is usually kept substantially constant. And
The fuel pressure during this determination period exhibits the above-described behavior regardless of the engine load fluctuation and engine speed. However, when fuel leaks from the fuel supply system from the fuel supply pump to the fuel injection valve, the fuel pressure in the accumulator significantly decreases during the determination period. According to the present invention, the fuel pressure change in the accumulator chamber detected during the determination period is calculated, and the fuel leakage from the fuel supply system is determined based on the fuel pressure change. Regardless, fuel leakage can be accurately detected even during operation of the internal combustion engine.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a schematic configuration diagram showing the configuration of the entire pressure accumulating fuel injection device of the embodiment. As shown in the figure, a pressure-accumulation type fuel injection device 1 of the present embodiment is a six-cylinder diesel engine 2
A fuel injection valve (injector) 3 for injecting fuel into each cylinder of the diesel engine 2; a pressure accumulating chamber (common rail) 4 for accumulating high-pressure fuel supplied to the injector 3; A fuel supply pump 5 and an electronic control circuit 6 for controlling the fuel supply pump 5 are provided.

The electronic control circuit 6 controls the rotational speed NE of the diesel engine 2 and the accelerator opening AF (the diesel engine 2) detected by the rotational speed sensor 7 and the accelerator sensor 8.
Corresponding to the load of the diesel engine 2
A target common rail pressure for realizing a fuel injection pressure such that the combustion state of the fuel cell becomes optimum in accordance with the detected operation state is calculated, and the actual common rail pressure detected in the common rail 4 by the pressure sensor 9 as the fuel pressure detecting means is calculated. The feedback control for driving and controlling the fuel supply pump 5 is performed so that the fuel pressure (common rail pressure Pc) of the fuel supply pump coincides with the target common rail pressure.

The fuel supply pump 5 comprises a pair of plunger pumps (hereinafter, referred to as a first pump 5a and a second pump 5b) for pumping fuel at a 240 ° CA cycle. Each pump 5a, 5b sets the phase of each plunger to 120 ° C.
A Different. Further, each of the pumps 5a and 5b sucks the fuel stored in the fuel tank 10 through the low-pressure pump 11 according to a control command from the electronic control circuit 6, and pressurizes the fuel internally to a high pressure. The high-pressure fuel is pressure-fed to the common rail 4 via the supply pipes 12a and 12b.
The control command for the fuel supply pump 5 is output at a predetermined timing based on a detection value from the rotation speed sensor 7 or a cylinder discrimination sensor (not shown). The internal structure of each of the pumps 5a and 5b is well known, and will not be described in detail here.

Each injector 3 is connected by a pipe 13
It is connected to a common rail 4 storing high-pressure fuel.
Then, by opening and closing the control valve 14 disposed in each injector 3, high-pressure fuel that has been accumulated by the common rail 4 and has reached the target fuel pressure is injected into the combustion chamber of each cylinder of the diesel engine 2. You. The opening and closing operation of the control valve 14 of the injector 3 is executed based on an injector drive pulse from the electronic control circuit 6.

Next, the change of the common rail pressure Pc in the pressure-accumulation type fuel injection device 1 configured as described above will be described with reference to a time chart of FIG. As shown in (b) and (d), the plungers (not shown) of the first pump 5a and the second pump 5b slide at a 240 ° CA cycle.
When the drive pulse shown in (a) and (c) is input from the electronic control circuit to the pump (the first pump 5a or the second pump 5b) whose plunger is rising, the pump operates the common rail 4 after a predetermined delay time TC. Start pumping fuel to The pump continues to pump fuel until the plunger reaches the top dead center, and pumps an amount of fuel proportional to the amount of plunger movement to the common rail 4 during that time. That is, when the electronic control circuit 6 outputs the first pump drive pulse or the second pump drive pulse at the predetermined timing TF,
Then, at timing Te after TC, the common rail pressure Pc
Begins to rise.

Each time the cylinder of the diesel engine 2 reaches the ignition timing, the electronic control circuit 6 controls the control valve 14 of the injector 3 belonging to the ignition cylinder to (e).
Is output. Then, almost at the same time as the pulse output, the injector 3 opens, and the fuel stored in the common rail 4 is injected into the cylinder. Therefore, when the electronic control circuit 6 outputs the injector drive pulse at a predetermined timing, the common rail pressure Pc decreases almost simultaneously. When the injector drive pulse is stopped at the predetermined timing Ti, the injector 3 closes and the fuel injection ends. The timings TF, Te, and Ti are defined by the time from a reference signal for cylinder determination to the timing.

Since the common rail pressure Pc exhibits such a behavior, the common rail pressure Pc is generally substantially equal to a period from the timing Ti when the injector driving pulse is stopped to the timing Te when the fuel supply of the fuel supply pump 5 is started. It is kept constant. However, when fuel leakage from the fuel supply system from the fuel supply pump 5 to the injector 3 occurs, the common rail pressure Pc decreases significantly during this period. Therefore, in the present embodiment, the common rail pressure Pc is measured at two points in the above period (this is referred to as Pc1, Pc1).
c2), and the fuel leakage from the fuel supply system is detected based on the pressure difference between the two common rail pressures Pc1 and Pc2. Subsequently, the fuel leak detection process executed by the electronic control circuit 6 will be described with reference to FIGS.

First, FIG. 3 is a flowchart showing a main routine of the fuel leak detection processing of the present embodiment. In addition,
This process is executed every predetermined period (for example, 3 msec.) During the operation of the diesel engine 2. When the process is started, first, in step 301, a threshold value Pt of the pressure decrease rate DPc used for determining fuel leakage is calculated based on the average value Pcc of the common rail pressure Pc and the fuel temperature using the map shown in FIG. The pressure drop rate DPc is a pressure drop rate per 1 msec while the common rail pressure Pc changes from Pc1 to Pc2, and is calculated by a process described later. Further, the average value Pcc can be substituted by the common rail pressure Pc detected at a predetermined timing (for example, between the timing Ti and the timing Te). Further, the fuel temperature is detected by a well-known fuel temperature sensor 20 provided in the fuel tank 10.

The map shown in FIG. 4 has the following characteristics. During a period from the timing Ti when the fuel is not supplied to the common rail 4 to the timing Te to the timing Te, even if the fuel supply system is normal, a small amount of fuel flows out of the gap of the valve of the injector 3. Therefore,
During this time, the common rail pressure Pc slightly decreases as illustrated in FIG. Further, as shown by a dashed line in the figure, the decreasing tendency of the common rail pressure Pc becomes more remarkable as the common rail pressure Pc becomes higher, and the lower the fuel viscosity becomes, the more the common rail pressure Pc becomes.
For example, it becomes remarkable as the fuel temperature increases. Therefore, the map of FIG. 4 is also prepared such that the higher the average value Pcc of the common rail pressure Pc and the higher the fuel temperature, the larger the threshold value Pt. In FIG. 5, the maximum value of the common rail pressure Pc is illustrated for comparison. Also,
In FIGS. 4 and 5, the fuel temperature is used as a viscosity parameter, but the viscosity of the fuel changes depending on parameters other than the temperature, for example, the type of fuel. Therefore, a higher-order map may be created in consideration of these parameters.

Returning to FIG. 3, in the following step 303,
Based on the pressure difference between the common rail pressures Pc1 and Pc2, it is determined whether or not the pressure reduction rate DPc calculated in a process described later has exceeded a threshold value Pt. When DPc> Pt, the process proceeds to the subsequent step 305, and when DPc ≦ Pt, the process is once terminated. When the determination at step 303 is affirmative and the routine proceeds to step 305, the abnormality counter N reset when the diesel engine 2 is started is incremented, and the routine proceeds to step 307. In step 307, it is determined whether or not the value of the abnormality counter N has exceeded 10. If it exceeds 10, at step 309, an abnormal flag Er indicating fuel leakage is set, and the process is temporarily terminated.
If N ≦ 10, the process is temporarily terminated. In addition,
When the abnormality flag Er is set, predetermined processing such as notification of abnormality to the driver is performed by another routine (not shown).

Next, a process for calculating the above-mentioned pressure drop rate DPc will be described. FIG. 6 shows the common rail pressure Pc1.
Is a flow chart showing a detection timing setting routine for detecting the common rail pressure Pc2 and detecting the common rail pressure Pc2. Note that this routine is executed as an interrupt process to the main routine when 2 msec. Has elapsed from the timing Ti.

When the process is started, in step 601,
The common rail pressure Pc detected at that time is defined as a common rail pressure Pc1. In the following step 603, it is determined whether the period from the timing Ti to the timing Te is longer than 7 msec. If an affirmative determination is made here, the routine proceeds to the subsequent step 605, where the determination period flag F is set to 2. Subsequently, in step 607, the timer Tm is set to 4 msec.
To end the process. Note that the determination period flag F
Is a flag indicating the length of a period (hereinafter, referred to as a determination period) from the detection timing of the common rail pressure Pc1 to the detection timing of the common rail pressure Pc2.

Also, Te-Ti ≦ 7 (msec.),
If a negative determination is made in step 603, the process moves to step 611. In step 611, Te-Ti is 4 msec.
Determine if it is longer. If an affirmative determination is made here, the routine proceeds to the subsequent step 613, where the determination period flag F is set to 1. Subsequently, at step 615, the timer Tm is set to 1 m.
Set to sec. and end the process.

On the other hand, Te−Tm ≦ 4 (msec.)
If a negative determination is made in step 611, the process is terminated after setting the determination period flag F to 0 in step 617.
When the determination period flag F is set to 0, the electronic control circuit 6 does not execute the pressure reduction rate calculation routine described below. Next, FIG. 7 is a flowchart showing a pressure reduction rate calculation routine for detecting the common rail pressure Pc2 and calculating the pressure reduction rate DPc. This routine is executed as an interrupt process to the main routine when the set time elapses after the timer Tm is set in step 607 or 615 described above.

When the process is started, in step 701,
The common rail pressure Pc detected at that time is defined as a common rail pressure Pc2. In the following step 703, the common rail pressure Pc2 detected in step 701 is subtracted from the common rail pressure Pc1 detected in step 601 described above, and the value is set as a pressure reduction rate DPc. In the following step 705, it is determined whether or not the determination period flag F is 1. When F = 1, the processing is terminated as it is, and F ≠ 1
That is, when F = 2, the process proceeds to the subsequent step 707. In step 707, the pressure drop rate DPc calculated in step 703 is divided by 4, and the process is terminated as a new pressure drop rate DPc.

That is, when the judgment period flag F is 1, the judgment period is 1 msec. Therefore, Pc1 -P
c2 is the pressure drop rate per 1 msec. However, when the determination period flag F is 2, the determination period is 4 msec. Therefore, Pc1-Pc2 is 4 msec.
Pressure reduction rate. Therefore, when F = 2, (Pc1−Pc2) / 4 is calculated as the pressure drop rate D in step 707.
Pc.

In the above processing, step 603 is executed.
Steps 703 to 615 correspond to the determination period detecting means, step 703 corresponds to the fuel pressure change calculating means, and steps 301 to 309 correspond to the fuel leakage determining means. By the above processing, in the present embodiment, as illustrated in FIG. 2F, 2 ms of the timing Ti at which the injector driving pulse stops is exemplified.
c. The common rail pressure Pc1 is detected later, and the common rail pressure Pc2 is detected 1 msec. or 4 msec. later. Further, the detection timing of the common rail pressure Pc2,
There is an interval of at least 1 msec between the fuel supply pump 5 and the timing Te at which the fuel is pumped to the common rail 4. Therefore, during the above-described determination period, the fuel injection by the injector 3 and the fuel supply by the fuel supply pump 5 hardly affect the change of the common rail pressure Pc. Therefore,
During the above-described determination period, the common rail pressure Pc is normally kept substantially constant regardless of the load fluctuation and the rotation speed of the diesel engine 2. In the case of fuel leakage, the common rail pressure Pc significantly decreases during the above-described determination period.

In the present embodiment, 1 m
The pressure drop rate DPc per sec. is calculated, and when the number of times the pressure drop rate exceeds the threshold value Pt exceeds 10 times, it is determined that the fuel leaks from the fuel supply system from the fuel supply pump 5 to the injector 3. . Therefore, in the accumulator-type fuel injection device 1 of the present embodiment, fuel leakage can be accurately detected regardless of the load fluctuation and the rotation speed of the diesel engine 2.

The present invention can be applied not only to a diesel engine but also to various internal combustion engines, for example, a direct injection spark ignition gasoline engine.

[0030]

As described above in detail, in the pressure accumulating fuel injection device according to the first aspect of the present invention, based on the change in the fuel pressure in the pressure accumulating chamber during the predetermined determination period during which neither the fuel pumping nor the fuel injection is executed. , The fuel leakage of the fuel supply system is detected. During this determination period , during operation of the internal combustion engine
Even, regardless of the load change and the rotational speed of the engine, the fuel pressure in the accumulation chamber is usually kept substantially constant. In the case of a fuel leak, the fuel pressure is significantly reduced during the determination period. For this reason, according to the first aspect of the present invention, fuel leakage is detected during operation of the internal combustion engine irrespective of engine load fluctuations and engine speed.
It can be detected accurately even. Further, in the pressure accumulating fuel injection device according to the second aspect of the present invention, based on a change in fuel pressure in the pressure accumulating chamber during a predetermined determination period during which neither fuel inflow to the pressure accumulating chamber nor fuel outflow from the pressure accumulating chamber is executed. Thus, fuel leakage of the fuel supply system is detected. During this determination period , the fuel pressure in the accumulator is normally kept substantially constant irrespective of the load fluctuation and the rotation speed of the engine even during the operation of the internal combustion engine . In the case of a fuel leak, the fuel pressure is significantly reduced during the determination period. For this reason, according to the second aspect of the present invention, fuel leakage can be accurately detected even during operation of the internal combustion engine , regardless of the load fluctuation and the engine speed of the engine .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a configuration of an entire pressure accumulating fuel injection device according to an embodiment.

FIG. 2 is a time chart showing a change in a common rail pressure in the embodiment.

FIG. 3 is a flowchart illustrating a main routine of a fuel leakage detection process according to the embodiment.

FIG. 4 is a map showing a relationship between a threshold value of a pressure decrease rate, a common rail pressure, and a fuel temperature.

FIG. 5 is a time chart showing differences in common rail pressure changes depending on average common rail pressure and fuel temperature.

FIG. 6 is a flowchart illustrating a detection timing setting routine according to the embodiment.

FIG. 7 is a flowchart illustrating a pressure reduction rate calculation routine according to the embodiment.

FIG. 8 is a diagram illustrating a configuration example of the present invention.

[Explanation of symbols]

1. Accumulation type fuel injection device 2. Diesel engine
3. Injector 4. Common rail 5. Fuel pump
6 Electronic control circuit 9 Pressure sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 41/00-45/00 F02M 39/00-71/04

Claims (5)

(57) [Claims] An accumulator for storing fuel in a high-pressure state, a fuel supply pump for pumping fuel to the accumulator at predetermined intervals , and an injector for supplying high-pressure fuel stored in the accumulator to each cylinder of an internal combustion engine. a fuel injection valve for, and a fuel pressure detecting means for detecting the fuel pressure in the accumulation chamber, the fuel pressure detected by the fuel pressure detecting means, the
Target fuel pressure set based on the operating state of the internal combustion engine
So that they coincide with each other in the predetermined cycle of the fuel supply pump.
In the accumulator fuel injection apparatus amount pumping is controlled to the pressure accumulation chamber, during operation of the internal combustion engine, or the fuel supply pump
Determination period detection means for detecting a predetermined determination period in which none of the fuel pumping by the pumping amount in the predetermined cycle and the fuel injection into each cylinder by the fuel injection valve is performed. Fuel pressure change calculating means for calculating a fuel pressure change in the accumulator detected by the fuel pressure detecting means; and a fuel supply system from the fuel supply pump to the fuel injection valve based on the calculated fuel pressure change. And a fuel leak determining means for determining fuel leak from the fuel tank. Wherein the accumulator chamber storing at high pressure fuel, a fuel supply pump for pumping fuel to the accumulating chamber at predetermined intervals, inject and supply high-pressure fuel stored in the accumulator chamber to each cylinder of the internal combustion engine a fuel injection valve for, and a fuel pressure detecting means for detecting the fuel pressure in the accumulation chamber, the fuel pressure detected by the fuel pressure detecting means, the
Target fuel pressure set based on the operating state of the internal combustion engine
So that they coincide with each other in the predetermined cycle of the fuel supply pump.
A pressure- accumulation-type fuel injection device in which the amount of pressure supplied to the pressure accumulation chamber is controlled ;
Determination period detection means for detecting a predetermined determination period during which neither inflow of fuel into the accumulator chamber and outflow of fuel from the accumulator chamber due to the pumping amount at the predetermined cycle is executed, and the determination period A fuel pressure change calculating means for calculating a fuel pressure change in the accumulator detected by the fuel pressure detecting means; and a fuel from the fuel supply pump to the fuel injection valve based on the calculated fuel pressure change. An accumulator-type fuel injection device, comprising: fuel leakage determination means for determining fuel leakage from a supply system. (3) The fuel leak determining means calculates
The change in fuel pressure is compared with a predetermined threshold value, and the
Is determined to be a fuel leak when
The predetermined threshold value of the fuel supply during the determination period is
Set in consideration of fuel pressure drop when supply system is normal.
The storage according to claim 1 or 2, wherein
Pressure fuel injector. (4) The above threshold value indicates that the fuel pressure in the accumulator is high.
4. The storage according to claim 3, wherein
Pressure fuel injector. (5) The above threshold value increases as the fuel temperature increases.
5. The storage according to claim 3, wherein the storage capacity is increased.
Pressure fuel injector.