JP5246003B2 - Fuel supply control device and fuel supply system using the same - Google Patents

Description

  The present invention supplies fuel injected from a fuel injection valve to a cylinder of an internal combustion engine from a feed pump. When the feed pressure of the feed pump exceeds a predetermined pressure, the relief valve opens to reduce the feed pressure. The present invention relates to a fuel supply control device used in a fuel supply system in which a check valve is installed in a bypass passage to bypass, and fuel is prohibited from flowing from the downstream side to the upstream side of the feed pump through the bypass passage.

  Conventionally, in a fuel supply system, when a feed pressure of a feed pump exceeds a predetermined pressure, a relief valve is opened to reduce the feed pressure of the feed pump. As a result, it is possible to prevent parts installed on the downstream side of the feed pump from being damaged due to excessive feed pressure.

  For example, in Patent Document 1, foreign matter in fuel supplied from a feed pump is prevented from getting caught in a downstream high-pressure pump, a sliding portion of a fuel injection valve, a valve portion of a fuel injection valve, or the like. In addition, foreign matters in the fuel are removed by a fuel filter installed on the downstream side of the feed pump. When the feed pressure of the feed pump exceeds a predetermined pressure, the relief valve opens to reduce the feed pressure of the feed pump, thereby preventing an excessive fuel pressure from being applied and damaging the fuel filter.

  In Patent Document 1, a check valve is installed in a bypass passage that can bypass the feed pump and supply fuel from the upstream side to the downstream side of the feed pump. A check valve installed in the bypass passage allows fuel flow from the upstream side to the downstream side of the feed pump and prohibits fuel flow from the downstream side to the upstream side of the feed pump.

  Thus, for example, after the fuel supply system is assembled, after the fuel filter is replaced, or when air enters the fuel passage due to the fuel tank running out of fuel, the feed pump is bypassed and the feed pump is bypassed. The check valve permits the fuel to flow through the bypass passage to the downstream side of the fuel, and the air that has entered the fuel passage can be removed. On the other hand, during the operation of the internal combustion engine (also referred to as an engine), the check valve prohibits the fuel pumped from the feed pump from returning from the downstream side to the upstream side of the feed pump through the bypass passage.

JP 2006-207499 A

  By the way, in the relief valve and the check valve installed in the bypass passage, if foreign matter is caught in the sliding part or the valve part, there is a possibility that the valve is stuck and the relief valve and the check valve are always opened. .

If the relief valve or the check valve is stuck open, the feed pressure of the feed pump does not rise sufficiently, which may cause engine start failure.
Further, during normal operation of the engine, the feed pressure of the feed pump does not increase sufficiently, so that, for example, the fuel injection pressure decreases, which may lead to insufficient output of the internal combustion engine or deterioration of emissions.

Therefore, it is desired that the fuel supply system detects that the relief valve and the check valve are stuck open and takes appropriate measures.
The present invention has been made to solve the above problems, and provides a fuel supply control device for determining whether or not a relief valve and a check valve are fixedly open and a fuel supply system using the same. For the purpose.

According to the first to fourth aspects of the present invention, the feed pressure detecting means detects the feed pressure of the feed pump based on the detection signal of the pressure sensor, and the feed pressure estimating means determines the feed pressure based on the operating state of the feed pump. The abnormality determining means detects that the relief valve and the check valve are fixedly opened based on the detected value of the feed pressure detected by the feed pressure detecting means and the estimated value of the feed pressure estimated by the feed pressure estimating means. It is determined whether or not.

  Since the relief valve opens when the feed pressure of the feed pump exceeds a predetermined pressure and reduces the feed pressure, the relief valve does not open or close correctly depending on the feed pressure when the valve is fixed. As a result, a deviation occurs between the detected value of the feed pressure detected based on the detection signal of the pressure sensor and the estimated value of the feed pressure estimated based on the operation state of the feed pump.

  Also, if the check valve installed in the bypass passage that bypasses the feed pump is stuck open, the fuel pumped from the feed pump returns from the downstream side of the feed pump to the upstream side through the check valve. A deviation occurs between the detected value of the feed pressure and the estimated value of the feed pressure.

Thereby, it can be determined whether the relief valve and the check valve are fixedly open based on the detected value and the estimated value of the feed pressure. As a result, it is possible to detect the valve sticking of the relief valve and the check valve and perform appropriate measures.
According to the first aspect of the present invention, the abnormality determination means is configured to detect at least one of the relief valve and the check valve when the detected value of the feed pressure is lower than the estimated value by a predetermined value during operation of the internal combustion engine. It is determined that one of the valves is stuck open.
When at least one of the relief valve and the check valve is stuck open, the detected value of the feed pressure becomes lower than the estimated value of the feed pressure beyond a predetermined range in consideration of tolerances. Therefore, when the detected value of the feed pressure is lower than the estimated value by a predetermined range, it can be determined that at least one of the relief valve and the check valve is stuck open.
Furthermore, according to the first aspect of the present invention, the abnormality determination means is configured such that, during operation of the internal combustion engine, the detected value of the feed pressure is lower than the estimated value by a predetermined range and the detected value of the feed pressure is the relief valve. When the check valve is equal to or higher than the estimated value of the feed pressure when the check valve is fully open when the check valve is normal, it is determined that the check valve is stuck open.
If the check valve is stuck open when the relief valve is operating normally according to the feed pressure, the feed pressure detection value is the estimated feed pressure when the check valve is fully open. That should be more. Therefore, during operation of the internal combustion engine, the detected value of the feed pressure is lower than the estimated value by a predetermined range, and the detected value of the feed pressure is the value of the feed pressure when the check valve is fully opened when the relief valve is normal. If it is equal to or greater than the estimated value, it can be determined that the check valve is stuck open.

  According to the second aspect of the present invention, when the abnormality determination means does not determine that the check valve is stuck open during operation of the internal combustion engine, the feed pressure is increased when the operation of the internal combustion engine is stopped. It is determined whether or not the relief valve is stuck open based on the amount of decrease in the estimated value and the amount of decrease in the detected value of the feed pressure.

When the operation of the internal combustion engine is stopped, the operation of the feed pump is also stopped, so that the fuel gradually leaks to the low pressure side, so that the residual pressure on the downstream side of the feed pump detected by the pressure sensor decreases. If the relief valve and the check valve are not stuck open and are normal, when the internal combustion engine is stopped, the detected value of the feed pressure decreases at substantially the same rate as the estimated value of the feed pressure. On the other hand, when the check valve is normal but the relief valve is stuck open, when the internal combustion engine stops, the amount of decrease in the detected value of the feed pressure is greater than the amount of decrease in the estimated value of the feed pressure. Therefore, if it is not determined that the check valve is stuck open during operation of the internal combustion engine, when the internal combustion engine stops, the amount of decrease in the detected value of the feed pressure and the estimated value of the feed pressure The abnormality of the relief valve can be determined based on the reduction amount.

According to the third aspect of the present invention, the feed pressure estimating means estimates the feed pressure based on the rotation speed of the feed pump.
Since the feed pressure of the feed pump changes according to the rotation speed of the feed pump, the feed pressure of the feed pump can be estimated with high accuracy based on the rotation speed of the feed pump.

  The functions of the plurality of means provided in the present invention are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of the plurality of means are not limited to those realized by hardware resources that are physically independent of each other.

The block diagram which shows the fuel supply system by this embodiment. (A) is a characteristic diagram showing the relationship between the rotation speed of the feed pump and the feed pressure, and (B) is a characteristic diagram showing the relationship between the passage of time after the engine is stopped and the residual pressure. The flowchart which shows the abnormality determination routine during engine operation. The flowchart which shows the abnormality determination routine when an engine stops.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A fuel supply system according to an embodiment of the present invention is shown in FIG.
(Fuel supply system 10)
The accumulator fuel supply system 10 of this embodiment supplies fuel pressurized by the fuel supply pump 30 to a fuel injection valve 80 that injects fuel into a cylinder of a four-cylinder diesel engine (not shown), for example.

  The fuel supply pump 30 includes a feed pump 32, a metering valve 42, a high-pressure pump 50, and the like, and the high-pressure pump 50 pressurizes fuel pumped up from the fuel tank 12 and pumped by the feed pump 32.

  The filters 14 and 34 are installed in the fuel passage 200 where the feed pump 32 sucks fuel from the fuel tank 12 and removes foreign matters in the fuel before the fuel is sucked into the feed pump 32. In FIG. 1, filters 14 and 34 and a filter 40 described later are relatively coarse filters such as a metal mesh.

  The priming pump 16 bypasses the feed pump 32 via the bypass passage 202 and supplies fuel to the downstream side of the feed pump 32 when the vehicle is assembled. The bypass passage 202 bypasses the feed pump 32 and connects the fuel filter 20 and the feed pump 32 that are upstream of the feed pump 32 and downstream of the feed pump 32.

  The fuel filter 20 is installed on the downstream side of the feed pump 32. For this reason, the feed pressure of the feed pump 32 is applied to the fuel filter 20. Thus, the fuel filter 20 is less likely to be clogged than the filters 14 and 34 installed on the fuel suction side of the feed pump 32 and on the upstream side of the feed pump 32. As a result, a filter element that is finer than the filters 14 and 34 can be used for the fuel filter 20, so that the filtration performance of the fuel filter 20 is higher than that of the filters 14 and 34.

  A pressure sensor 22 is installed between the feed pump 32 and the fuel filter 20. The pressure sensor 22 outputs a detection signal corresponding to the fuel pressure between the feed pump 32 and the fuel filter 20, that is, the feed pressure of the feed pump 32.

The relief valve 24 opens when the fuel pressure applied to the fuel filter 20 exceeds a predetermined pressure, and discharges excess fuel from the escape passage 204 to the fuel tank 12.
The feed pump 32 is a known trochoid pump or vane pump. The feed pump 32 is rotationally driven by the camshaft 52 in the same manner as the high-pressure pump 50. The camshaft 52 is rotationally driven by the crankshaft of the engine. As indicated by a solid line 300 in FIG. 2A, the feed pressure Fp of the feed pump 32 increases as the feed pump speed Np increases. However, when the feed pump speed Np exceeds Np0 and the feed pressure exceeds a predetermined pressure, which is the valve opening pressure of the relief valve 36, the relief valve 36 opens, so the feed pump speed Np is Np0. If it exceeds, the rate of increase of the feed pressure decreases.

  The relief valve 36 opens when the feed pressure of the feed pump 32 exceeds a predetermined pressure that is the opening pressure of the relief valve 36. As a result, the fuel on the downstream side of the feed pump 32 is returned from the relief valve 36 to the upstream side of the feed pump 32, so that the feed pressure of the feed pump 32 is reduced.

  The check valve 38 is installed in the bypass passage 202. The check valve 38 prohibits fuel flow from the downstream side of the feed pump 32 to the upstream side of the feed pump 32, and permits fuel flow from the upstream side of the feed pump 32 to the downstream side of the feed pump 32. In FIG. 1, the check valve 38 is installed inside the fuel supply pump 30, but may be installed outside the fuel supply pump 30.

  For example, when the priming pump 16 is operated after the fuel supply system 10 is assembled, the check valve 38 opens, bypasses the feed pump 32, passes through the bypass passage 202, and fuel flows from the fuel filter 20 to the high pressure pump 50. Supplied. As a result, the air entering the fuel passage for supplying fuel from the feed pump 32 to the high-pressure pump 50 can be eliminated.

  The fuel from which foreign matter has been removed by the fuel filter 20 passes through the fuel passage 210 and is supplied to the metering valve 42. The filter 40 is installed on the upstream side of the metering valve 42 and removes foreign matters in the fuel supplied to the metering valve 42.

  The metering valve 42 is an electromagnetic valve whose opening degree is controlled based on the engine operating state. When the opening of the metering valve 42 is controlled, the fuel intake amount sucked into the high-pressure pump 50 is adjusted, and the fuel discharge amount discharged from the high-pressure pump 50 is adjusted.

  The fuel passage 212 returns the fuel leaking from the metering valve 42 to the upstream side of the feed pump 32 when the metering valve 42 is closed. The fuel passage 214 supplies part of the fuel supplied from the feed pump 32 to the cam chamber of the high-pressure pump 50 as lubricating oil.

  The plunger 56 of the high-pressure pump 50 reciprocates as the cam 54 rotates together with the cam shaft 52, and pressurizes the fuel sucked into the pressurizing chamber. Two plungers 56 are installed on the opposite side in the radial direction across the camshaft 52.

  The intake valve 60 opens when fuel is sucked from the metering valve 42 into the pressurizing chamber, and closes when fuel is discharged from the pressurizing chamber. On the other hand, the discharge valve 62 is closed when fuel is sucked into the pressurizing chamber from the metering valve 42, and is opened when fuel is discharged from the pressurizing chamber.

  The fuel discharged from the high-pressure pump 50 is supplied to the common rail 70 through the fuel passage 216. The common rail 70 accumulates the fuel supplied from the high pressure pump 50. The pressure limiter 72 opens when the fuel pressure in the common rail 70 (hereinafter also referred to as common rail pressure) exceeds a predetermined pressure, and reduces the common rail pressure. When the pressure limiter 72 is opened, the fuel in the common rail 70 is discharged from the fuel passage 220 to the fuel tank 12. The fuel leaking from the high-pressure pump 50 and the fuel injection valve 80 is also discharged into the fuel passage 220.

The fuel accumulated in the common rail 70 is injected from the fuel injection valve 80 into the cylinder of the diesel engine.
An electronic control unit (ECU: Electronic Control Unit) 90 is configured by a microcomputer centering on a CPU, ROM, RAM, flash memory, and the like. The ECU 90 takes in detection signals from various sensors including the pressure sensor 22, an accelerator opening (Accp) sensor, and an engine speed (NE) sensor, and controls the engine operating state.

  For example, the ECU 90 regulates the fuel discharge amount of the high-pressure pump 50 by controlling the amount of current supplied to the metering valve 42 and adjusting the fuel intake amount of the high-pressure pump 50. Further, the ECU 90 controls the fuel injection amount of the fuel injection valve 80, the fuel injection timing, and the multi-stage injection pattern in which pilot injection, post injection, etc. are performed before and after the main injection.

The ECU 90 functions as the following means by a control program stored in the ROM or flash memory.
(Feed pressure detection means)
The ECU 90 detects the feed pressure of the feed pump 32 based on the detection signal of the pressure sensor 22 installed between the feed pump 32 and the fuel filter 20.

(Feed pressure estimation means)
The feed pressure of the feed pump 32 is determined by the discharge amount of the feed pump 32, and the discharge amount of the feed pump 32 is determined by the rotation speed of the feed pump 32. As described above, since the feed pump 32 is rotationally driven by the camshaft 52, the rotational speed of the feed pump 32 is determined by the engine rotational speed (NE). The ECU 90 stores the relationship between the rotation speed Np of the feed pump 32 and the feed pressure Fp as a characteristic indicated by a solid line 300 in FIG. Thus, the ECU 90 can estimate the feed pressure Fp with high accuracy based on the rotation speed Np of the feed pump 32.

(Abnormality judgment means)
The ECU 90 detects the feed pressure detection value Psout of the feed pump 32 detected by the feed pressure detection means based on the detection signal of the pressure sensor 22, and the feed pressure estimated by the feed pressure estimation means based on the rotation speed Np of the feed pump 32. Whether or not the relief valve 36 and the check valve 38 are stuck open is determined based on the difference between the estimated value Fp and the estimated value Fp.

(Determination of valve opening sticking during engine operation)
(1) During operation of the engine, if the relief valve 36 and the check valve 38 are not stuck open and normal, the relationship between the rotational speed Np of the feed pump 32 and the feed pressure Fp is the detected value of the feed pressure. Including the range of the tolerance Pt of Psout, the characteristics shown by the solid line 300 in FIG.

  When the rotational speed Np of the feed pump 32 is lower than the idle rotational speed Npi, the rotational speed Np becomes unstable. Therefore, the relief valve 36 and the check valve are checked based on the detected value Psout of the feed pressure and the estimated value Fp. It may be difficult to determine whether the valve 38 is stuck open. Therefore, it is desirable to determine whether or not the relief valve 36 and the check valve 38 are stuck open in a range where the rotational speed Np of the feed pump 32 is equal to or higher than the idle rotational speed Npi.

  The feed pressure detection value Psout detected from the detection signal of the pressure sensor 22 is estimated from the solid line 300 in the range where the rotation speed Np of the feed pump 32 is equal to or higher than the idle rotation speed Npi as the predetermined rotation speed. When the feed pressure detection value Psout is lower than the estimated value Fp by exceeding a predetermined range, at least one of the relief valve 36 and the check valve 38 is stuck open. Therefore, it can be determined that the feed pressure has decreased.

  Here, when the relief valve 36 is normal but the check valve 38 is stuck open, the estimated value Fp is equal to or higher than the pressure when the check valve 38 is fully open. In FIG. 2A, a solid line 302 indicates an estimated value Fp when the check valve 38 is fully opened when the relief valve 36 is normal.

Therefore, when the detected value Psout of the feed pressure indicated by the dotted line 304 is lower than the value obtained by subtracting the tolerance Pt from the estimated value Fp of the feed pressure indicated by the solid line 300 and is equal to or greater than the value indicated by the solid line 302, the relief valve 36 is used. Is normal, but it is determined that the check valve 38 is stuck open.
(2) When the detected value Psout of the feed pressure is lower than the solid line 302, it is determined that both the relief valve 36 and the check valve 38 are stuck open.
(3) Although the check valve 38 is normal and is not stuck open, it is difficult to determine during operation of the engine that the relief valve 36 is stuck open. Originally, when the rotational speed Np of the feed pump 32 increases and the feed pressure increases, the relief valve 36 is opened to reduce the feed pressure, so that the rotational speed of the feed pump 32 is maintained even if the relief valve 36 is fixedly open. When Np increases and the detection value Psout increases, the difference between the detection value Psout and the estimated value Fp decreases. Therefore, it is difficult to determine whether the relief valve 36 is stuck open based on the detected value Psout and the estimated value Fp.

(Determination of valve opening sticking when the engine stops)
When the engine is stopped, the detected value of the residual pressure detected by the pressure sensor 22 between the feed pump 32 and the fuel filter 20 gradually decreases as indicated by the solid line 310 in FIG.

  However, if the check valve 38 is not fixed and the relief valve 36 is fixed, the feed pump 32 and the fuel filter 20 are not connected as shown by the dotted line 312 in FIG. The residual pressure in between decreases to the atmospheric pressure earlier than a predetermined time required when the relief valve 36 decreases to the atmospheric pressure when it is normal. When the engine is stopped, the ECU 90 detects the amount of decrease in the detected value of the residual pressure between the feed pump 32 and the fuel filter 20, that is, the detected value of the detected feed pressure based on the detected signal of the pressure sensor 22. It is determined that the relief valve 36 is stuck open when the estimated value is larger than the estimated decrease amount.

(Abnormality judgment routine)
Next, an abnormality determination routine for determining whether the relief valve 36 and the check valve 38 are stuck open will be described with reference to the flowcharts shown in FIGS. FIG. 3 is an abnormality determination routine during engine operation, and FIG. 4 is an abnormality determination routine when the engine is stopped. The routine of FIG. 3 is always executed. The routine of FIG. 4 is executed when it is not determined in the routine of FIG. 3 that the check valve 38 is stuck open. In FIG. 3 and FIG. 4, “S” represents a step.

(Abnormality judgment routine during engine operation)
In S400 of FIG. 3, the ECU 90 determines whether or not the rotational speed Np of the feed pump 32 is higher than the idle rotational speed Npi as a predetermined rotational speed. When the rotation speed Np of the feed pump 32 is equal to or lower than the idle rotation speed Npi (S400: No), the ECU 90 ends this routine.

  When the engine is in operation and the rotational speed Np of the feed pump 32 is higher than the idle rotational speed Npi (S400: Yes), in S402, the ECU 90 determines that the detected value Psout of the feed pressure is the tolerance Pt from the estimated value Fp of the feed pressure. It is determined whether or not the value is lower than the value obtained by subtracting (Fp−Pt). If Psout ≧ Fp−Pt (S402: No), the ECU 90 ends this routine.

  If Psout <Fp−Pt (S402: Yes), in S404, the ECU 90 causes the detected value Psout of the feed pressure to be fully opened when the relief valve 36 is not open and fixed and the check valve 38 is in a normal state. It is determined whether or not the estimated value of the feed pressure is Fcfo or more.

  If Fcfo ≦ Psout is satisfied (S404: Yes), the ECU 90 determines that the relief valve 36 is normal and not open, but the check valve 38 is fixed and open (S406). When the check valve 38 is stuck open, the ECU 90 preferably notifies the driver of the abnormality of the check valve 38 by a warning light or the like. As a result, appropriate measures such as replacing the check valve 38 can be quickly implemented.

  If Fcfo> Psout (S404: No), the ECU 90 determines that both the relief valve 36 and the check valve 38 are stuck open (S408). Also in this case, it is desirable that the ECU 90 informs the driver of the abnormality of the relief valve 36 and the check valve 38 by a warning light or the like. As a result, appropriate measures such as exchanging the relief valve 36 and the check valve 38 can be quickly implemented.

(Abnormal judgment routine when the engine stops)
In S420 of FIG. 4, the ECU 90 determines whether the engine has stopped and the rotation speed Np of the feed pump 32 has become zero. If Np = 0 is not satisfied (S420: No), it is determined that the engine is not stopped, and the ECU 90 ends this routine.

  If Np = 0 (S420: Yes), the ECU 90 determines that the engine has stopped, and counts the elapsed time after the engine stops (S422). When the predetermined time has elapsed (S424: Yes), in S426, the ECU 90 detects the detected elapsed time T required until the detected value of the residual pressure between the feed pump 32 and the fuel filter 20 becomes 0 corresponding to the atmospheric pressure (see FIG. 2 (see (B)) is shorter than the estimated elapsed time t estimated that the residual pressure between the feed pump 32 and the fuel filter 20 is zero when the relief valve 36 and the check valve 38 are normal. That is, it is determined whether or not the detected value of the feed pressure decreases earlier than the predetermined time with respect to the estimated value of the feed pressure. In other words, it is determined whether or not the amount of decrease in the detected value of the feed pressure is larger than the amount of decrease in the estimated value of the feed pressure.

  When t> T (S426: Yes), the ECU 90 determines that the relief valve 36 is stuck open while it is not determined that the check valve 38 is stuck open during engine operation. To do.

  When the relief valve 36 is stuck open, as described above, the ECU 90 desirably notifies the driver of the abnormality of the relief valve 36 by a warning light or the like. Thereby, appropriate measures, such as exchanging the relief valve 36, can be implemented quickly.

If t ≦ T (S426: No), the ECU 90 determines that the relief valve 36 is not stuck open, and ends this routine.
In the present embodiment, the relief valve 36 corresponds to the relief valve described in the claims. In this embodiment, the function of referring to the detected value Psout of the feed pump 32 in S402 and S404 corresponds to the function of the feed pressure detecting means, and the function of referring to the estimated value Fp of the feed pump 32 in S402. Corresponds to the function of the feed pressure estimation means. In S402 and S404, the function of determining whether the relief valve 36 and the check valve 38 are stuck open based on the detected value Psout of the feed pump 32 and the estimated value Fp corresponds to the function of the abnormality determining means.

  In the present embodiment described above, during the engine operation, whether or not the check valve 38 is stuck open based on the detected value Psout and the estimated value Fp of the feed pump 32, or the relief valve 36 and the reverse valve It is determined whether or not both stop valves 38 are stuck open.

  Further, when it is determined that the check valve 38 is not stuck open during engine operation when the engine is stopped, the amount of decrease in the detected value Psout of the feed pump 32 and the amount of decrease in the estimated value Fp Based on the above, it is determined whether the relief valve 36 is stuck open.

  Accordingly, when at least one of the relief valve 36 and the check valve 38 is stuck open, an abnormality is notified, and at least one of the relief valve 36 and the check valve 38 is replaced. Can be implemented promptly.

[Other Embodiments]
In the above-described embodiment, the example in which the present invention is applied to the fuel supply system of a common rail type diesel engine that pressurizes the fuel supplied by the feed pump 32 with the high-pressure pump 50 and accumulates the fuel with the common rail 70 has been described. In contrast, when the feed pressure of the feed pump exceeds a predetermined pressure, the relief valve opens to reduce the feed pressure, and a check valve is installed in the bypass passage that bypasses the feed pump. As long as the check valve prohibits fuel flow to the side and the check valve permits fuel flow from the upstream side to the downstream side of the feed pump, it is not limited to common rail or diesel engines, The present invention may be applied to a fuel supply system for an engine.

  In addition, the relief valve may be used not only for protecting the fuel filter but also for other purposes, and the check valve installed in the bypass passage for bypassing the feed pump is used not only for priming but also for other purposes. Also good.

  In the above embodiment, the functions of the feed pressure detection means, the feed pressure estimation means, and the abnormality determination means are realized by the ECU 90 whose functions are specified by the control program. On the other hand, at least a part of the functions of the above means may be realized by hardware whose function is specified by the circuit configuration itself.

  As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

10: fuel supply system, 16: priming pump, 20: fuel filter, 22: pressure sensor, 30: fuel supply pump, 32: feed pump, 36: relief valve, 38: check valve, 50 high pressure pump, 70: common rail 80: Fuel injection valve, 90: ECU (fuel supply control device, feed pressure detecting means, feed pressure estimating means, abnormality determining means)

Claims (4)

A feed pump for supplying fuel to be injected into a cylinder of the internal combustion engine by a fuel injection valve;
A relief valve that opens when the feed pressure of the feed pump exceeds a predetermined pressure to reduce the feed pressure;
The fuel flow is installed in a bypass passage that bypasses the feed pump, prohibits fuel flow from the downstream side of the feed pump to the upstream side of the feed pump, and flows from the upstream side of the feed pump to the downstream side of the feed pump. A check valve that permits
In a fuel supply control device used for a fuel supply system comprising:
A feed pressure detecting means for detecting a feed pressure of the feed pump based on a detection signal of a pressure sensor installed downstream of the feed pump;
A feed pressure estimating means for estimating the feed pressure based on an operating state of the feed pump;
Whether the relief valve and the check valve are fixedly open based on the detected value of the feed pressure detected by the feed pressure detecting means and the estimated value of the feed pressure estimated by the feed pressure estimating means An abnormality determination means for determining whether or not
With
When the detected value is lower than the estimated value during the operation of the internal combustion engine during the operation of the internal combustion engine, the abnormality determination unit is configured to fix at least one of the relief valve and the check valve. Further, during the operation of the internal combustion engine, the check valve is fully opened when the detected value is lower than the estimated value by a predetermined range and the detected value is normal. If it is greater than or equal to the estimated value at the time, it is determined that the check valve is stuck open,
A fuel supply control device.   If the abnormality determining means does not determine that the check valve is stuck open during operation of the internal combustion engine, and the operation of the internal combustion engine stops, the amount of decrease in the estimated value and the 2. The fuel supply control device according to claim 1, wherein it is determined whether or not the relief valve is stuck open based on a decrease amount of the detected value. 3. The fuel supply control device according to claim 1, wherein the feed pressure estimation unit estimates the feed pressure based on a rotation speed of the feed pump. A common rail that supplies fuel accumulated in a fuel injection valve that injects fuel into a cylinder of the internal combustion engine;
A high pressure pump for supplying pressurized fuel to the common rail;
A feed pump that pumps fuel sucked up from a fuel tank to the high-pressure pump;
A fuel filter installed on the downstream side of the feed pump to remove foreign matters in the fuel supplied from the feed pump;
A priming pump that supplies fuel to a bypass passage that bypasses the feed pump during priming;
A relief valve that opens when the feed pressure of the feed pump exceeds a predetermined pressure to reduce the feed pressure;
Fuel that is installed in the bypass passage, prohibits fuel flow from the downstream side of the feed pump to the upstream side of the feed pump, and from the upstream side of the feed pump to the downstream side of the feed pump during priming by the priming pump A check valve that allows flow; and
The fuel supply control device according to any one of claims 1 to 3 ,
A fuel supply system comprising:

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