JP2017031932A - Fuel supply device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a drive load of a fuel pump 71 while protecting a pressure regulator 76 arranged in a fuel return pipe 74 in a liquefied gas fuel supply system 7 of an engine 1.SOLUTION: A fuel supply device for an engine includes first flow rate calculating means (step ST1) for calculating a fuel flow rate required for fuel injection by an injector 4, second flow rate calculating means (steps ST2-ST6) for calculating a return flow rate required for protecting the pressure regulator 76, and fuel pump control means (step ST7) for controlling a flow rate of LPG fuel pressure-fed from the fuel pump 71 based on the calculated flow rates. The return flow rate calculated by the second flow rate calculating means in stopping of the engine 1 is made to be smaller than in operation of the engine 1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fuel supply device for an engine using liquefied gas fuel, and particularly to a technical field of fuel pump control suitable when a pressure regulator is provided in a fuel return passage.

  Conventionally, it is known to use a liquefied gas fuel such as LPG (Liquefied Petroleum Gas) as a fuel for an engine mounted on a vehicle. For example, in the fuel supply device described in Patent Document 1, liquefied gas fuel is supplied to a fuel injection valve in a liquid phase state and injected into an intake port. Since the fuel often contains vapor (vapor phase fuel) when starting the engine, the amount of fuel pumped from the fuel pump is increased in order to suppress deterioration in startability.

  Further, in liquefied gas fuel such as LPG, vapor is generated by receiving heat from an engine in a delivery pipe or the like, and the mixing ratio varies depending on the composition and properties of the fuel. Focusing on this point, the fuel supply device of Patent Document 2 estimates the fuel composition by detecting the temperature and pressure in the fuel tank, and also considers the temperature of the fuel in the delivery pipe, and the liquid density of the fuel. And the vapor mixing ratio are estimated, and the fuel injection amount is corrected accordingly.

JP 2003-200140 A JP-A-2005-337023

  By the way, in the fuel supply device described in Patent Document 2, a pressure regulator is disposed in a return passage for returning surplus fuel that has not been injected to the fuel tank. It is desirable to let the fuel flow. However, if the flow rate of the fuel flowing through the return passage is larger than necessary, the driving load of the fuel pump increases unnecessarily.

  In this regard, as described in Patent Document 2, the amount of fuel injected from the fuel injection valve during the operation of the engine varies depending on the composition, properties, vapor mixing ratio, and the like. In view of the variation, conventionally, it is necessary to supply a large amount of fuel so that the flow rate of the fuel in the return passage is not insufficient, and there remains room for reducing the driving load of the fuel pump in this respect. .

  In view of such problems, an object of the present invention is to reduce the driving load of the fuel pump as compared with the prior art while protecting the pressure regulator disposed in the return passage in the apparatus for supplying liquefied gas fuel to the engine. There is to do.

  In order to achieve the above object, in the present invention, it is assumed that the engine is repeatedly operated and stopped as in a hybrid vehicle, for example, and it is not necessary to consider the variation in the fuel injection amount while the engine is stopped. did.

  Specifically, the present invention includes a supply passage for supplying liquefied gas fuel to the fuel injection valve in a liquid phase and a return passage for returning excess fuel to the fuel tank, and a pressure regulator is disposed in the return passage. The target is the fuel supply device of the engine. And the 1st flow rate calculation means which calculates the fuel flow rate required for fuel injection by the fuel injection valve, and the 2nd flow rate calculation means which calculates the fuel flow rate of the return passage required for protection of the pressure regulator And a fuel pump control means for controlling the flow rate of the fuel pumped from the fuel pump to the supply passage based on the fuel flow rates calculated by the first and second flow rate calculation means, respectively, and stopping the engine The fuel flow rate calculated by the second flow rate calculation means is smaller than that during engine operation.

  According to the above specific matter, first, during the operation of the engine, the fuel flow rate required for fuel injection is calculated by the first flow rate calculation means, and the fuel flow rate in the return passage required for protecting the pressure regulator ( Hereinafter, the return flow rate) is calculated by the second flow rate calculation means. Based on the calculated fuel flow rate and return flow rate, the fuel pump control means controls the flow rate of the fuel pumped from the fuel pump.

  Here, during the operation of the engine, in consideration of the variation in the fuel injection amount, the return flow rate is calculated by the second flow rate calculation means so that the fuel flow rate is not insufficient in the return passage. On the other hand, since fuel injection is not performed while the engine is stopped, there is no need to consider the variation, and the return flow rate is calculated to be smaller than that during engine operation. For this reason, the flow rate of the fuel pumped from the fuel pump is reduced, and the driving load is reduced.

  As described above, according to the fuel supply apparatus for an engine according to the present invention, the fuel flow rate required for fuel injection and the return flow rate required for protection of the pressure regulator are calculated, and based on these, the fuel pump While controlling the flow rate of fuel to be pumped and reducing the return flow rate when the engine is stopped compared to during operation, it is possible to protect the pressure regulator and reduce the driving load of the fuel pump than before. it can.

It is a schematic structure figure of an engine concerning an embodiment. It is a flowchart of the flow control routine of a fuel pump. It is an image figure showing generation | occurrence | production of the vapor | steam by the raise of the fuel temperature in a delivery pipe, and the countermeasure for preventing this on the vapor pressure diagram of LPG fuel.

  Hereinafter, an embodiment in which the present invention is applied to an engine mounted on a hybrid vehicle will be described with reference to the drawings. In the present embodiment, an engine that uses LPG fuel as liquefied gas fuel will be described.

  As schematically shown in FIG. 1, in the present embodiment, the engine 1 is a four-cylinder reciprocating engine as an example, and the first to fourth cylinders # 1 to # 4 have pistons 2 respectively. It is accommodated and reciprocates in the cylinder in synchronization with the rotation of a crankshaft (not shown). A crank angle sensor 101 for detecting the rotation speed of the crankshaft, that is, the engine rotation speed is provided.

  In the intake passage 3 of the engine 1, the downstream side of the surge tank 30 (downstream side of the intake flow) branches for each cylinder, and there is liquefied gas fuel (hereinafter referred to as LPG fuel) toward the intake port. 4 injectors (fuel injection valves) 4 are arranged. The injector 4 is operated in accordance with a control signal from the ECU 100, and LPG fuel injected in a liquid phase from the injection hole is mixed with intake air while being vaporized, thereby forming an air-fuel mixture in a combustion chamber in the cylinder.

  Further, a throttle valve 31 is disposed upstream of the surge tank 30 in the intake passage 3 and is driven by a throttle motor 31a in accordance with a control signal from the ECU 100, thereby adjusting the flow rate of intake air. ing. The opening of the throttle valve 31 (throttle opening) is detected by a throttle opening sensor 102. An air flow meter 103 and an intake air temperature sensor 104 that measure the flow rate of intake air are disposed upstream of the throttle valve 31.

  The mixture of the intake air and the LPG fuel that have been passed through the intake passage 3 and sucked into the cylinder is ignited and burned by the spark plug 5, and the combustion gas generated thereby is discharged into the exhaust passage 6. The combustion gas, that is, the exhaust gas from the engine 1 gathers in the exhaust manifold 60 that is the most upstream part of the exhaust passage 6, is purified by the catalytic converter 61 provided on the downstream side thereof, and then is discharged into the atmosphere. In the exhaust passage 6, an air-fuel ratio sensor 105 is disposed upstream of the catalytic converter 61, and an oxygen concentration sensor 106 is disposed downstream.

-Fuel supply system-
A fuel supply system 7 (fuel supply device) that supplies LPG fuel to the four injectors 4 includes a fuel tank 70 that stores LPG fuel, a fuel pump 71 that is an electric pump, and an LPG that is pumped from the fuel pump 71. A fuel supply pipe (supply path) 73 that supplies fuel to the delivery pipe 72 and a fuel return pipe (return path) 74 that returns excess LPG fuel to the fuel tank 70 are provided.

  In the fuel pump 71, the electric motor 71 a is operated in accordance with a control signal from the ECU 100, sucks LPG fuel in the fuel tank 70, and pumps it to the fuel supply pipe 73. The LPG fuel flows through the fuel supply pipe 73 and is distributed from the delivery pipe 72 to the injector 4. The fuel tank 70 is provided with an in-tank fuel temperature sensor 107 and an in-tank fuel pressure sensor 108 so as to detect the temperature and pressure of the LPG fuel, respectively.

  The delivery pipe 72 has a function as a pressure accumulating container that temporarily stores the LPG fuel that is circulated through the fuel supply pipe 73 as described above, and detects the temperature and pressure of the LPG fuel, respectively. In addition, an in-delivery fuel temperature sensor 109 and an in-delivery fuel pressure sensor 110 are provided. In addition, an electromagnetic valve 75 is disposed in the fuel supply pipe 73 so that the fuel supply pipe 73 can be switched to an open state or a closed state in accordance with a control signal from the ECU 100.

  On the other hand, in the fuel return pipe 74, a pressure regulator 76, an electromagnetic valve 77, and a fuel cooler 78 are arranged in order from the upstream side of the flow of LPG fuel returning to the fuel tank 70. The pressure regulator 76 is opened when the fuel pressure in the delivery pipe 72 becomes higher than a predetermined level, whereby the fuel pressure in the delivery pipe 72 can be adjusted to a predetermined pressure. The electromagnetic valve 77 is switched to an open state or a closed state according to a control signal from the ECU 100.

  In the fuel supply system configured as described above, the electromagnetic valves 75 and 77 of the fuel supply pipe 73 and the fuel return pipe 74 are both opened during the operation of the engine 1. Of the LPG fuel that is pumped to the delivery pipe 72 by the operation of the fuel pump 71, surplus LPG fuel excluding that injected from the injector 4 flows through the fuel return pipe 74 and is returned to the fuel tank 70. It becomes like this.

  Even when the engine 1 is stopped, the solenoid valves 75 and 77 are opened in a predetermined state during operation of the hybrid system of the vehicle, and the LPG fuel pumped to the delivery pipe 72 by the operation of the fuel pump 71 is The fuel is returned to the fuel tank 70 through the fuel return pipe 74. Thereby, the pressure regulator 76 is protected. The fuel cooler 78 cools the LPG fuel flowing through the fuel return pipe 74 by heat exchange with a refrigerant of an air conditioner (not shown).

-ECU-
The ECU 100 is a known electronic control unit, and includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a backup RAM, and the like (not shown). The CPU executes various arithmetic processes based on the control program and map stored in the ROM. In addition, the RAM temporarily stores calculation results in the CPU, data input from each sensor, and the like, and the backup RAM stores data to be saved when the engine 1 is stopped, for example.

  The ECU 100 includes a crank angle sensor 101, a throttle opening sensor 102, an air flow meter 103, an intake air temperature sensor 104, an air-fuel ratio sensor 105, an oxygen concentration sensor 106, an in-tank fuel temperature sensor 107, an in-tank fuel pressure sensor 108, An in-delivery fuel temperature sensor 109, an in-delivery fuel pressure sensor 110, and the like are connected, and although not shown, an accelerator opening sensor that detects an operation amount (accelerator opening) of an accelerator pedal is also connected. Yes.

  On the other hand, the throttle motor 31a, the injector 4, the electric motor 71a of the fuel pump 71, and actuators such as the electromagnetic valves 75 and 77 are connected to the ECU 100. In addition, an igniter for adjusting the ignition timing of the ignition plug 5 and the like. Is also connected. Then, the ECU 100 executes various control programs based on signals input from the various sensors and the like, thereby appropriately operating the various actuators to execute operation control of the engine 1.

  For example, the ECU 100 calculates the required torque for the engine 1 based on the accelerator opening, the load factor and the rotational speed of the engine 1, the vehicle speed, and the like, and controls the throttle opening (that is, the intake air intake so that the required torque can be output). Volume control). Further, the ECU 100 calculates the amount of intake air charged into the cylinder from the flow rate of intake air and the engine speed, and controls the fuel injection amount by the injector 4 in accordance with this, so that the stoichiometric air-fuel ratio is obtained. Furthermore, the ECU 100 also performs overall control of the hybrid system (motor generator torque control, battery charge / discharge control, etc.).

  In addition, in the present embodiment, the ECU 100 controls the flow rate of the LPG fuel that is pumped to the fuel supply pipe 73 by controlling the rotational speed of the electric motor 71a of the fuel pump 71 as described below. That is, the ECU 100 calculates a fuel flow rate required for fuel injection by the injector 4 and a return flow rate required for protection of the pressure regulator 76, adds these, and adds the fuel flow rate from the fuel pump 71 to the fuel supply pipe. The flow rate of the LPG fuel pumped to 73 is calculated.

-Fuel pump flow control-
Next, flow control of the fuel pump 71, which is a feature of this embodiment, will be described. As described above, the ECU 100 controls the fuel pump 71 so that the return flow rate of the LPG fuel becomes necessary for protection of the pressure regulator 76 in a predetermined state even when the engine 1 is stopped. Yes. This is because it is necessary to constantly flow LPG fuel through the fuel return pipe 74 so that the seal portion of the on-off valve of the diaphragm is not fixed in the pressure regulator 76.

  However, if the amount of LPG fuel flowing through the fuel return pipe 74 is larger than necessary, the driving load of the fuel pump 71 will increase unnecessarily. That is, the amount of LPG fuel injected from the injector 4 during the operation of the engine 1 varies depending on its composition, properties, vapor mixing ratio, and the like. This is because the flow rate of the LPG fuel pumped from 71 must be increased.

  On the other hand, in the hybrid vehicle as in the present embodiment, the engine 1 is appropriately stopped according to the traveling state and the battery state, and fuel injection is not performed while the engine is stopped. There is no need. Focusing on this point, in the present embodiment, when the engine 1 is stopped, the return flow rate is calculated to be smaller than that during operation, and the pumping amount of LPG fuel from the fuel pump 71 is reduced, thereby reducing the driving load. I try to reduce it.

  Hereinafter, the flow control routine of the fuel pump 71 in the present embodiment will be specifically described with reference to FIG. This routine is repeatedly executed at a predetermined timing during operation of the hybrid system of the vehicle. In the flowchart shown in FIG. 2, step ST1 after the start and steps ST2 to ST6 are performed in parallel, but this may be performed in order.

  In the illustrated example, first, in step ST1, based on a predetermined number of fuel injection amounts by the injector 4, the supply amount of LPG fuel necessary for these fuel injections (the flow rate of LPG fuel pumped from the fuel pump 71) is calculated. Then, the process proceeds to step ST7 described later. The fuel injection amount by the injector 4 may be calculated using the control target value of the fuel injection amount calculated for the operation control of the engine 1 by the ECU 100 and stored in the RAM.

  More specifically, the charge amount of intake air into the cylinder is calculated based on the intake air flow rate measured by the air flow meter 103 and the engine speed (calculated from the signal of the crank angle sensor 101). The amount of LPG fuel that can achieve the stoichiometric air-fuel ratio is calculated. Further, at that time, based on the estimated fuel composition (propane ratio) and the like, correction according to the liquid density of LPG fuel and the mixing ratio of vapor is performed.

  The composition and properties of the LPG fuel are estimated based on the temperature and pressure of the LPG fuel in the fuel tank 70 detected by the in-tank fuel temperature sensor 107 and the in-tank fuel pressure sensor 108 by experiments and simulations in advance. This is performed with reference to a set fuel composition map (not shown). Based on the estimated fuel composition and the temperature of the LPG fuel in the delivery pipe 72 detected by the in-delivery fuel temperature sensor 109, a correction coefficient for the liquid density and the vapor mixing ratio is calculated.

  On the other hand, in steps ST2 to ST6, the return flow rate of the LPG fuel necessary for protecting the pressure regulator 76 is calculated. First, in step ST2, it is determined whether or not the fuel cooler 78 of the fuel return pipe 74 is operating. For example, the fuel temperature detected by the in-delivery fuel temperature sensor 109 is equal to or higher than a predetermined temperature, and the fuel cooler 78 is operating. If affirmative determination is made (YES), the process proceeds to step ST3, a large flow rate set in advance is selected (high return flow rate), and the process proceeds to step ST7 described later.

The fuel cooler 78 supplies the LPG fuel that circulates in the fuel return pipe 74 in order to ensure fuel supply when the temperature of the LPG fuel in the fuel tank 70 is equal to or higher than a predetermined temperature and the pressure is high. It is to be cooled. In order to efficiently cool the LPG fuel in the fuel cooler 78, a flow rate suitable as the large flow rate (for example, 40 L / sec) is adapted in advance by experiments and simulations, while the fuel cooler 78 is activated in the step ST2. If the determination is negative (NO), the process proceeds to step ST4, where it is determined whether the engine 1 is stopped. For example, if an affirmative determination is made that the engine 1 is stopped based on the signal from the crank angle sensor 101, the operating state of the injector 4, etc. (YES), the routine proceeds to step ST5 and is set in advance to protect the pressure regulator 76. The selected small flow rate is selected (return flow rate is small), and the process proceeds to Step ST7 described later.

  If it is determined that the engine 1 is not stopped (NO), the process proceeds to step ST6, an intermediate flow rate between the large flow rate and the small flow rate is selected (during return flow rate), and the flow proceeds to step ST7 described later. The small flow rate (for example, 5 L / sec) is obtained by adapting the minimum flow rate of the required LPG fuel by experiments and simulations in advance so that the seal portion of the diaphragm on-off valve does not stick in the pressure regulator 76. is there. Further, the intermediate flow rate (for example, 20 L / sec) is obtained by adding a predetermined amount to the small flow rate so that the return flow rate is not insufficient even when the variation in the fuel injection amount is large.

  In step ST7, the fuel flow rate for fuel injection calculated in step ST1 is added to the return flow rate calculated in any of steps ST3, ST5, ST6. The flow rate of LPG fuel to be pumped (target value for flow rate control) is calculated. The flow rate of the LPG fuel is controlled by controlling the rotational speed of the electric motor 71a of the fuel pump 71 by a control signal output from the ECU 100 based on the fuel flow rate.

  However, in this embodiment, in step ST8, it is determined whether or not a vehicle collision or an abnormality of the fuel supply system 7 (for example, malfunction of the fuel pump 71, leakage of LPG fuel from the piping, etc.) has occurred. The collision of the vehicle is determined based on a signal from an acceleration sensor mounted on the vehicle, for example. Further, malfunction of the fuel pump 71, leakage of LPG fuel, and the like are determined based on signals from the in-tank fuel pressure sensor 108 and the in-delivery fuel pressure sensor 110.

  If a negative determination is made that no collision or abnormality in the fuel supply system 7 has occurred (NO), the routine proceeds to step ST9, where the lower limit guard process is applied to the pumping amount of the LPG fuel by the fuel pump 71, and then the routine is executed. End (end). This lower limit guard process is a process of increasing the flow rate of the LPG fuel pumped from the fuel pump 71 so that the LPG fuel is maintained in the liquid phase state in the delivery pipe 72.

  Specifically, as schematically shown in FIG. 3, when the temperature of the LPG fuel is plotted on the horizontal axis and the pressure is plotted on the vertical axis, the vapor pressure diagram of the LPG fuel is represented. When the LPG fuel is pumped to the delivery pipe 72 by the fuel pump 71, the fuel pressure rises as indicated by an arrow, and the fuel is usually received from the point A to the point B due to heat received from the engine 1 in the delivery pipe 72. The temperature also rises. In this case, the LPG fuel in the delivery pipe 72 is kept in a liquid phase state above the saturated vapor pressure line.

  On the other hand, when the engine 1 is in an operation state with a large calorific value, such as high load and high rotation, and the amount of heat received in the delivery pipe 72 increases, the temperature of the LPG fuel rises significantly as shown by point C. A gas phase is formed below the pressure line, and a large amount of bubbles (vapor) are generated. In this case, the amount of fuel injected from the injector 4 cannot be controlled as intended.

  Therefore, as described above, the saturated vapor pressure line as shown in FIG. 3 is obtained from the fuel composition (propane ratio and the like) estimated based on the temperature and pressure of the LPG fuel in the fuel tank 70, and then delivered. Based on the temperature of the LPG fuel in the delivery pipe 72 detected by the internal fuel temperature sensor 109, if the differential pressure between the pressure of the LPG fuel and the saturated vapor pressure is below a predetermined threshold, the fuel pump is accordingly The flow rate of the LPG fuel pumped from 71 is increased.

  As the flow rate of the LPG fuel from the fuel pump 71 is increased in this way, the fuel pressure in the delivery pipe 72 is further increased, and the rise in fuel temperature due to heat received from the engine 1 is mitigated, and the vapor pressure line in FIG. In the figure, the LPG fuel is maintained in a liquid phase state as schematically shown as point C → point D. Thereby, the fuel injection as intended can be performed by the injector 4.

  On the other hand, if an affirmative determination is made in step ST8 that a collision or abnormality in the fuel supply system 7 has occurred (YES), the process proceeds to step ST10, the lower limit guard process is prohibited, and the routine is terminated ( End). As a result, when a component of the fuel supply system 7 is out of order, it is possible to prevent the degree of failure from being deteriorated due to an increase in the flow rate of the LPG fuel or an increase in the amount of leakage of LPG fuel. Further, if the vehicle is in a collision, an increase in the amount of leakage can be prevented before the expected leakage of LPG fuel occurs.

  By executing step ST1 of the flow of FIG. 2, the ECU 100 constitutes a first flow rate calculating means for calculating the fuel flow rate required for fuel injection by the injector 4, and by executing steps ST2 to ST6. The ECU 100 constitutes a second flow rate calculation means for calculating a return flow rate necessary for protecting the pressure regulator 76. Further, by executing step ST7, the ECU 100 constitutes a fuel pump control means for controlling the flow rate of the LPG fuel pumped from the fuel pump 71 by adding the values calculated by the first and second flow rate calculation means. .

  As described above, in the fuel supply system 7 of the engine 1 according to the present embodiment, the fuel flow rate necessary for fuel injection from the injector 4 and the return flow rate necessary for protecting the pressure regulator 76 are Based on the above, by controlling the flow rate of the LPG fuel pumped from the fuel pump 71, the drive load of the fuel pump 71 is suppressed as much as possible, thereby reducing the power consumption of the electric motor 71a, Fuel consumption can be reduced.

  In addition, while the engine 1 is stopped, it is not necessary to calculate a large return flow rate due to the variation in the fuel injection amount. Therefore, in this embodiment, the return flow rate is the minimum required for protecting the pressure regulator 76. The flow rate (a small flow rate set in advance) is set, and accordingly, the fuel flow rate from the fuel pump 71 can be reduced to further reduce the driving load.

-Other embodiments-
The description of the above-described embodiment is merely an example, and is not intended to limit the configuration or application of the present invention. For example, in the above-described embodiment, as shown in the flowchart of FIG. 2, it is determined in step ST2 whether or not the fuel cooler 78 is operating, and if it is operating, the process proceeds to step ST3 and the return flow rate is set to a large flow rate. However, the steps ST2 and ST3 need not be executed.

  Similarly, in the above embodiment, in step ST8 of the flowchart of FIG. 2, it is determined whether there is a vehicle collision or an abnormality in the fuel supply system 7, and if these occur, the process proceeds to step ST10 and the lower limit guard process is prohibited. However, the steps ST8 and ST10 need not be executed.

  Moreover, although the said embodiment demonstrated the case where this invention was applied to the engine 1 mounted in the hybrid vehicle, this invention is applicable not only to this but vehicles other than a hybrid vehicle. Further, the liquefied gas fuel used in the engine 1 is not limited to LPG, and liquefied natural gas (LNG), dimethyl ether, liquid hydrogen, or the like may be used, or a plurality of types of fuels are used in combination. May be.

  The present invention is applied to an engine using a liquefied gas fuel such as LPG and reduces the driving load of the fuel pump as much as possible, thereby contributing to improvement of fuel consumption. Is expensive.

1 Engine 4 Injector (fuel injection valve)
7 Fuel supply system (fuel supply system)
70 Fuel tank 71 Fuel pump 72 Delivery pipe 73 Fuel supply pipe (supply passage)
74 Fuel return pipe (return passage)
76 Pressure regulator 100 ECU (first flow rate calculation means, second flow rate calculation means, fuel pump control means)

Claims (1)

An engine fuel supply device comprising a supply passage for supplying liquefied gas fuel to a fuel injection valve in a liquid phase state and a return passage for returning surplus fuel to a fuel tank, wherein a pressure regulator is provided in the return passage. There,
First flow rate calculating means for calculating a fuel flow rate required for fuel injection by the fuel injection valve;
A second flow rate calculating means for calculating a fuel flow rate of the return passage required for protecting the pressure regulator;
Fuel pump control means for controlling the flow rate of fuel pumped from the fuel pump to the supply passage based on the fuel flow rates respectively calculated by the first and second flow rate calculation means,
A fuel supply apparatus for an engine, wherein the fuel flow rate calculated by the second flow rate calculation means when the engine is stopped is smaller than that during engine operation.

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