JP2005248807A - Fuel supply device and fuel supply control device - Google Patents

Abstract

Dispersion of a fuel injection amount caused by temperature characteristics of a fuel injection valve is suppressed.
The fuel supply device 50 supplies fuel to an internal combustion engine. The fuel supply device 50 is attached to the internal combustion engine 1, and stores a delivery pipe 2 that stores fuel supplied from the high-pressure pump 10, and is attached to the delivery pipe 2 and supplies fuel supplied from the delivery pipe 2 to the internal combustion engine. The fuel injection valves 3 _{1 to} 3 ₄ that are injected into the respective cylinders 1 s _{1 to 1} s ₄ , and the relief valve 11 that allows excess fuel in the delivery pipe 2 to escape. Then, the amount of fuel supplied to the delivery pipe 2 is changed based on the amount of heat transferred from the internal combustion engine 1 to the fuel in the delivery pipe 2.
[Selection] Figure 2

Description

  The present invention relates to a reciprocating internal combustion engine that directly injects fuel into a cylinder by means of a fuel injection valve, and more particularly to supply of fuel to the fuel injection valve.

A so-called direct injection internal combustion engine that injects fuel directly into a cylinder and ignites it directly injects fuel during the compression stroke to form a mixture that is easily ignited by retaining fuel spray near the spark plug, It separates from the surrounding air layer, that is, stratifies. In this state, an ultra lean combustion operation can be realized by igniting and burning the air-fuel mixture in the vicinity of the spark plug and operating under so-called stratified combustion. As a result, the fuel consumption of the internal combustion engine can be improved and the amount of CO ₂ emission can be reduced.

  A direct-injection internal combustion engine is operated under a so-called homogeneous combustion in which fuel is directly injected into the cylinder during the intake stroke to diffuse the fuel into the cylinder to form and burn a homogeneous mixture. You can also. In the homogeneous combustion region, the intake air can be further cooled by the heat of vaporization of the fuel directly injected into the cylinder during the intake stroke, so that the charging efficiency can be increased. Thereby, a high output can be obtained in the operation in the homogeneous combustion region of the direct injection internal combustion engine. Due to such advantages, in recent years, direct-injection spark ignition internal combustion engines have attracted attention and have been put into practical use.

  The direct injection internal combustion engine includes a fuel injection valve that injects fuel into the cylinder. The fuel injection valve is attached to a fuel distribution pipe called a delivery pipe, from which high-pressure fuel is supplied. In Patent Document 1, for the purpose of preventing rotational fluctuation caused by the difference in fuel temperature between cylinders, when the temperature distribution of fuel flowing through the delivery pipe exceeds an allowable range, the amount of fuel supplied to the delivery pipe is set. A technique for reducing the temperature distribution range of the fuel by increasing it is disclosed.

JP-A-11-336629

  By the way, the fuel injection valve is configured to open and close the fuel injection hole by operating a needle valve provided in the outer shell of the fuel injection valve, and to inject high-pressure fuel supplied to the fuel injection valve from the fuel injection hole. Things are common. In such a fuel injection valve, a difference in thermal expansion occurs between the needle valve and the fuel injection valve outer shell due to the difference between the temperature of the fuel flowing inside and the external temperature. Since the stroke of the needle valve is regulated by the outer shell of the fuel injection valve, when the difference in thermal expansion occurs, the stroke of the needle valve changes and the fuel injection amount changes. This is called the temperature characteristic of the fuel injection valve.

  As in the technique disclosed in Patent Document 1, when the temperature distribution of the fuel flowing through the delivery pipe exceeds the allowable range, the temperature characteristic of the fuel injection valve is not increased only by increasing the amount of fuel supplied to the delivery pipe. This is insufficient to suppress the resulting variation in the fuel injection amount. In particular, when the fuel injection amount changes abruptly, it is difficult to control following the temperature characteristics of the fuel injection valve, and the air-fuel ratio may be distorted due to variations in the fuel injection amount. Therefore, the present invention has been made in view of the above, and an object of the present invention is to provide a fuel supply device and a fuel supply control device that can suppress variations in the fuel injection amount due to the temperature characteristics of the fuel injection valve. .

  In order to solve the above-described problems and achieve the object, a fuel supply apparatus according to the present invention supplies fuel to an internal combustion engine, is attached to the internal combustion engine, and is supplied from fuel pumping means. A delivery pipe that stores fuel, a fuel injection valve that is attached to the delivery pipe and injects fuel supplied from the delivery pipe into a cylinder of the internal combustion engine, and a relief valve that allows excess fuel in the delivery pipe to escape The amount of fuel supplied to the delivery pipe is changed based on the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe.

  The fuel supply device changes the amount of fuel supplied to the delivery pipe based on the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe. If the amount of fuel supplied to the delivery pipe is determined in this way, the fuel injection amount of the fuel injection valve, that is, the fuel temperature in the delivery pipe can be maintained within a predetermined range regardless of the load of the internal combustion engine. As a result, variations in the fuel injection amount due to the temperature characteristics of the fuel injection valve can be suppressed.

  The fuel supply apparatus according to the present invention is characterized in that, in the fuel supply apparatus, the amount of fuel supplied to the delivery pipe is increased while the amount of heat increases.

  This fuel supply device changes the amount of fuel supplied to the delivery pipe as the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe increases. By determining the amount of fuel supplied to the delivery pipe in this way, the fuel temperature in the delivery pipe can be maintained within a predetermined range even if the fuel injection amount of the fuel injection valve changes. As a result, variations in the fuel injection amount due to the temperature characteristics of the fuel injection valve can be suppressed.

  In the fuel supply apparatus according to the next aspect of the present invention, in the fuel supply apparatus, the amount of heat is a difference between a water temperature of cooling water that cools the internal combustion engine and an intake air temperature of air that is taken in by the internal combustion engine. Features.

  Since this fuel supply apparatus has the same configuration as the fuel supply apparatus, the same operation and effect as the fuel supply apparatus are achieved. Further, in this fuel supply device, the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe is represented by the difference between the coolant temperature for cooling the internal combustion engine and the intake air temperature taken in by the internal combustion engine. Thereby, since the coolant temperature and the intake air temperature can be measured using existing sensors, there is no need to provide separate sensors.

  The fuel supply apparatus according to the present invention is characterized in that, in the fuel supply apparatus, the relief valve has a fuel pressure adjustment function capable of changing a pressure of fuel in the delivery pipe.

  Since this fuel supply apparatus has the same configuration as the fuel supply apparatus, the same operation and effect as the fuel supply apparatus are achieved. Further, in this fuel supply device, since the relief valve has a fuel pressure adjusting function, the amount of fuel passing through the delivery pipe can be made constant. Thereby, the fuel temperature in the delivery pipe can be maintained within a predetermined range, and variations in the fuel injection amount due to the temperature characteristics of the fuel injection valve can be suppressed. In addition, since the relief valve has a fuel pressure adjustment function, the pressure of the fuel in the delivery pipe can be varied.

  In the fuel supply device according to the next invention, in the fuel supply device, when the control device that controls the operation of the internal combustion engine learns a correction value of the fuel injection amount injected from the fuel injection valve, Alternatively, the amount of fuel supplied to the delivery pipe is adjusted based on the amount of heat under at least one of the conditions when the air-fuel ratio feedback of the exhaust gas of the internal combustion engine cannot be performed.

  Since this fuel supply apparatus has the same configuration as the fuel supply apparatus, the same operation and effect as the fuel supply apparatus are achieved. Further, the fuel supply device adjusts the amount of fuel supplied to the delivery pipe under specific conditions. Thereby, since the amount of fuel supplied to the delivery pipe can be adjusted within a necessary and sufficient range, it is possible to reduce the driving force loss of the internal combustion engine caused by driving the fuel pumping means.

  A fuel supply control device according to the present invention includes a delivery pipe that stores fuel to be supplied to an internal combustion engine, and a fuel that is attached to the delivery pipe and is supplied from the delivery pipe into a cylinder of the internal combustion engine. A fuel injection valve that controls the amount of fuel supplied to the delivery pipe based on the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe. A fuel amount determining unit for determining the amount of the fuel is provided.

  The fuel supply control device controls the amount of fuel supplied to the delivery pipe based on the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe. As a result, the fuel injection amount of the fuel injection valve, that is, the fuel temperature in the delivery pipe can be maintained within a predetermined range regardless of the load of the internal combustion engine. As a result, variations in the fuel injection amount due to the temperature characteristics of the fuel injection valve can be suppressed.

  In the fuel supply control device according to the next aspect of the present invention, in the fuel supply control device, the fuel amount determination unit increases the amount of fuel supplied to the delivery pipe as the heat amount increases. It is characterized by determining the quantity.

  The fuel supply control device controls the amount of fuel supplied to the delivery pipe to be changed as the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe increases. Thereby, even if the fuel injection amount of the fuel injection valve changes, the fuel temperature in the delivery pipe can be maintained within a predetermined range. As a result, variations in the fuel injection amount due to the temperature characteristics of the fuel injection valve can be suppressed.

  In the fuel supply control apparatus according to the next aspect of the present invention, in the fuel supply control apparatus, the amount of heat is a difference between a water temperature of cooling water that cools the internal combustion engine and an intake air temperature of air that is taken in by the internal combustion engine. It is characterized by that.

  Since the fuel supply control device has the same configuration as the fuel supply control device, the fuel supply control device has the same operations and effects as the fuel supply control device. Further, this fuel supply control device handles the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe by the difference between the coolant temperature for cooling the internal combustion engine and the intake air temperature taken in by the internal combustion engine. This makes it possible to measure the coolant temperature and the intake air temperature using sensors already attached to the internal combustion engine, so that there is no need to provide separate sensors.

  The fuel supply control device according to the present invention is characterized in that, in the fuel supply control device, the control device that controls the operation of the internal combustion engine learns a correction value of the fuel injection amount injected from the fuel injection valve. Or a control condition determination unit that determines that at least one of the conditions when the air-fuel ratio feedback of the exhaust gas of the internal combustion engine cannot be performed, and when the fuel amount determination unit meets the condition, The amount of fuel supplied to the delivery pipe is determined based on the amount of heat.

  Since the fuel supply control device has the same configuration as the fuel supply control device, the fuel supply control device has the same operations and effects as the fuel supply control device. Further, the fuel supply control device controls to adjust the amount of fuel supplied to the delivery pipe under specific conditions. Thereby, since the amount of fuel supplied to the delivery pipe can be adjusted within a necessary and sufficient range, it is possible to reduce the driving force loss of the internal combustion engine caused by driving the fuel pumping means.

  According to the fuel supply device and the fuel supply control device of the present invention, it is possible to suppress the variation in the fuel injection amount caused by the temperature characteristic of the fuel injection valve.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the best mode for carrying out the invention. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same. The present invention can be applied to any reciprocating internal combustion engine that directly injects fuel into a cylinder, and can also be applied to a diesel engine in addition to a direct injection spark ignition internal combustion engine. In particular, it can be preferably applied to an internal combustion engine mounted on a vehicle such as a passenger car, a bus, or a truck.

  The fuel supply device and the fuel supply control device according to this embodiment are characterized in that the amount of fuel supplied to the delivery pipe is adjusted based on the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe.

  FIG. 1 is a cross-sectional view of one cylinder provided in the internal combustion engine according to this embodiment. The internal combustion engine 1 is a spark ignition type reciprocating internal combustion engine, in which fuel is directly injected into a cylinder 1 s by a fuel injection valve 3 to form an air-fuel mixture. A piston 5 is disposed in the cylinder 1s of the internal combustion engine 1 and reciprocates by combustion of the air-fuel mixture. The fuel injection valve 3 is supplied with fuel from a delivery pipe 2 serving as fuel distribution means, and directly injects the fuel into the cylinder 1s. The fuel directly injected into the cylinder 1s by the fuel injection valve 3 forms an air-fuel mixture with the air A introduced through the intake manifold 4 into the cylinder 1s.

  Fuel is injected into the cylinder 1s from the fuel injection valve 3 at a timing and a required amount according to the load KL of the internal combustion engine 1 and the engine speed NE. The fuel injected from the fuel injection valve 3 into the cylinder 1 s is led to the intake manifold 4 and then forms an air-fuel mixture with the air A introduced into the cylinder 1 s through the intake valve 58. It is ignited and burns. The combustion pressure of the air-fuel mixture is transmitted to the piston 5 and causes the piston 5 to reciprocate.

  The reciprocating motion of the piston 5 is transmitted to the crankshaft 6 through the connecting rod 6e, where it is converted into rotational motion and taken out as the output of the internal combustion engine 1. The combusted air-fuel mixture becomes exhaust gas Ex and is discharged to the exhaust passage 9 through the exhaust valve 59. The exhaust gas is purified by the catalyst 51 provided in the exhaust passage 9 and released into the atmosphere.

An engine ECU 30 (Electronic Control Unit) that controls the operation of the internal combustion engine 1 includes a crank angle sensor 41, an accelerator opening sensor 42, an air flow sensor 43, a cooling water temperature sensor 44, an intake air temperature sensor 45, and an O ₂ attached to the internal combustion engine 1. The output from the sensor 46 and other various sensors is acquired, and the operation of the internal combustion engine 1 is controlled. As will be described later, a fuel supply control device according to this embodiment is incorporated in the engine ECU 30.

FIG. 2 is a conceptual diagram showing an example of a fuel supply apparatus according to this embodiment. The internal combustion engine 1 to which the fuel supply device 50 supplies fuel is a four-cylinder internal combustion engine, but the application target of the present invention is not limited to this, and may be a six-cylinder, eight-cylinder, or single-cylinder internal combustion engine. The fuel in the fuel tank 26 is sent by the feed pump 12 through the fuel supply pipe 60 to the high pressure pump 10 that is a fuel pressure sending means. The high-pressure pump 10 is driven by the camshaft 13 of the internal combustion engine 1 and raises the fuel to a pressure required for the fuel injection valves 3 _{1 to} 3 ₄ . The fuel sent out from the high-pressure pump 10 is sent to the delivery pipe 2 and distributed to the respective fuel injection valves 3 _{1 to} 3 ₄ for injecting the fuel into the cylinders 1s ₁ to 1s ₄ .

  A relief valve 11 is attached to the outlet 2 o of the delivery pipe 2. In order to prevent the fuel in the delivery pipe 2 from exceeding the set pressure, the relief valve 11 is opened when the fuel pressure in the delivery pipe 2 exceeds the set pressure. Then, excess fuel is returned to the fuel tank 26 through the fuel relief passage 62. The relief valve 11 is configured to press the valve body 11v against the relief valve inlet 11i by a spring 11s. When the pressure of the fuel in the delivery pipe 2 rises and exceeds the pressing force of the spring 11s, the valve body 11v is pushed up, and the fuel in the delivery pipe 2 passes the fuel through the fuel relief passage 62 to the fuel tank 26. Returned to Next, the high pressure pump 10 that supplies fuel to the fuel injection valve 3 will be described.

  FIGS. 3-1 to 3-4 are explanatory diagrams illustrating the operation of the high-pressure pump according to this embodiment. The high pressure pump 10 includes a metering pressure feeding mechanism. As shown in FIGS. 3-1 to 3-3, the high-pressure pump 10 includes a spill valve 10s, a plunger 10p, and a check valve 10c. The high-pressure pump 10 pressurizes the fuel as the plunger 10p reciprocates. Then, by closing the spill valve 10s provided on the fuel suction port 10i side at an optimal timing during the pressurization stroke of the high-pressure pump 10, the fuel pressure and the fuel amount required for the internal combustion engine 1 can be controlled. . Here, the spill valve 10 s can be opened and closed by electromagnetic force, and the spill valve 10 s is opened and closed by a control signal from the engine ECU 30.

  FIG. 3A shows a state where the spill valve 10s is opened and the plunger 10p is stroked toward the suction side (corresponding to a portion indicated by A in FIG. 3-4). In this state, fuel is sucked into the plunger 10p from the fuel inlet 10i. 3-2 shows a state in which the spill valve 10s is opened and the plunger 10p is stroked to the discharge side (corresponding to a portion indicated by B in FIG. 3-4). In this state, the spill valve 10s is open, and the discharge pressure of the plunger 10p is lower than the valve opening pressure of the check valve 10c. For this reason, the fuel sucked into the plunger 10p is returned to the fuel tank from the fuel inlet 10i. FIG. 3C shows a state in which the spill valve 10s is closed and the plunger 10p is stroked to the discharge side (corresponding to a portion indicated by C in FIG. 3-4). In this state, since the spill valve 10s is closed, the discharge pressure of the plunger 10p is higher than the valve opening pressure of the check valve 10c. As a result, the check valve 10c is opened, and the fuel sucked into the plunger 10p is discharged from the fuel discharge port 10o to the delivery pipe 2.

  If the spill valve 10s is closed at an early timing, the effective stroke of the plunger 10p can be lengthened, so that the pressure of the fuel can be increased. With such a metering pressure feeding mechanism, the high-pressure pump 10 can change the amount of fuel supplied to the delivery pipe 2. In this embodiment, the fuel pressure in the delivery pipe 2 is determined by the valve opening pressure of the relief valve 11 provided in the delivery pipe 2.

  FIG. 4 is a conceptual diagram showing another example of the fuel supply device used in the internal combustion engine according to this embodiment. In this fuel supply device 50 ′, a relief valve having a fuel pressure adjusting function capable of changing the pressure of the fuel in the delivery pipe 2 is used instead of the relief valve 11 provided in the delivery pipe 2. In order to realize the fuel pressure adjustment function, the fuel supply device 50 ′ uses an electromagnetic relief valve 14. The electromagnetic relief valve 14 operates the valve body 14v by energizing the electromagnetic solenoid 14e. Further, the valve body 14v is pressed against the relief valve inlet 14i by the spring 14s. Thereby, when the energization of the electromagnetic solenoid 14e is cut off, the relief valve inlet 14i is closed by the valve body 14v.

  By controlling the operation amount of the electromagnetic relief valve 14, the fuel pressure in the delivery pipe 2 can be changed. A pressure sensor 47 for measuring the internal fuel pressure is attached to the delivery pipe 2. The engine ECU 30 acquires a signal from the pressure sensor 47 and performs feedback control, whereby the fuel pressure in the delivery pipe 2 can be controlled to a predetermined value.

  By using the electromagnetic relief valve 14, the fuel pressure supplied to the delivery pipe 2 can be varied even when a constant pressure is fed by the high-pressure pump 10. Further, the amount of fuel passing through the delivery pipe 2 can be controlled to be constant by operating the electromagnetic relief valve. Thereby, it becomes easy to control the fuel temperature in the delivery pipe 2 to be constant. Furthermore, as in the configuration shown in FIG. 4, if the high-pressure pump 10 has a metering function, the control of the fuel supply amount and the control of the fuel pressure can be executed simultaneously.

  In the fuel supply system shown in FIGS. 2 and 4, the relief valve 11 or the electromagnetic relief valve 14 provided in the delivery pipe 2 is the flow direction of the fuel flowing in the delivery pipe 2 (the direction of arrow F in FIGS. 2 and 4). Is attached to the most downstream. If it does in this way, it can control that the temperature of the fuel in delivery pipe 2 changes locally. Further, the fuel temperature distribution in the delivery pipe 2 can also be suppressed. As a result, it is possible to suppress variations in the fuel injection amount between the fuel injection valves, and to suppress A / F (Air / Fuel: air-fuel ratio) deviation. The relief valve 11 or the electromagnetic relief valve 14 may be arranged at a location other than the most downstream side of the delivery pipe 2 in consideration of mounting the internal combustion engine 1 on a vehicle and the layout of auxiliary machinery.

  FIG. 5 is an explanatory view showing a fuel supply control device according to this embodiment. The fuel supply control according to this embodiment can be realized by the fuel supply control device 20 according to this embodiment. The fuel supply control device 20 is configured to be incorporated in the engine ECU 30. In addition, the fuel supply control device 20 according to this embodiment may be prepared separately from the engine ECU 30 and connected to the engine ECU 30. In realizing the operation control method for the internal combustion engine according to this embodiment, the fuel supply control device 20 may be configured to use the control function of the internal combustion engine 1 provided in the engine ECU 30.

  The fuel supply control device 20 includes a control condition determination unit 21 and a fuel amount determination unit 22. These are the parts that execute the operation control method for the internal combustion engine according to this embodiment. The control condition determination unit 21 and the fuel amount determination unit 22 are connected via an input / output port (I / O) 39 of the engine ECU 30. Thereby, the control condition determination part 21 and the fuel quantity determination part 22 are comprised so that each can exchange data bidirectionally. Note that data may be transmitted and received in one direction as required in the apparatus configuration (the same applies hereinafter).

  The fuel supply control device 20, the processing unit 30p of the engine ECU 30 and the storage unit 30m are connected via an input / output port (I / O) 39 provided in the engine ECU 30, and exchange data with each other. can do. As a result, the fuel supply control device 20 acquires the load, engine speed, and other operation control data of the internal combustion engine of the engine ECU 30, and controls the fuel supply control device 20 to operate the internal combustion engine of the engine ECU 30. Or interrupt the control routine.

The input / output port (I / O) 39 includes a crank angle sensor 41, an accelerator opening sensor 42, an air flow sensor 43, a cooling water temperature sensor 44, an intake air temperature sensor 45, an O ₂ sensor 46, and other components of the internal combustion engine 1. Sensors that acquire information related to driving are connected. Thereby, the engine ECU 30 and the fuel supply control device 20 can acquire information necessary for operation control of the internal combustion engine 1. The input / output port (I / O) 39 is connected to a control target of the internal combustion engine 1 such as the high-pressure pump 10. These operations are controlled by control signals from the fuel amount determination unit 22 provided in the fuel supply control device 20 and the processing unit 30p of the engine ECU 30.

  The storage unit 30m stores a computer program including a processing procedure of the operation control method of the internal combustion engine according to this embodiment, a data map of a fuel injection amount used for operation control of the internal combustion engine 1, and the like. Here, the storage unit 30m can be configured by a volatile memory such as a RAM (Random Access Memory), a nonvolatile memory such as a flash memory, or a combination thereof. Further, the fuel supply control device 20 and the processing unit 30p of the engine ECU 30 can be configured by a memory and a CPU.

  The computer program may be capable of realizing the processing procedure of the fuel supply control according to this embodiment in combination with the computer program already recorded in the control condition determination unit 21 and the fuel amount determination unit 22. The fuel supply control device 20 may realize the functions of the control condition determination unit 21 and the fuel amount determination unit 22 using dedicated hardware instead of the computer program. Next, a procedure for realizing the operation control method for the internal combustion engine according to this embodiment using the fuel supply control device 20 will be described. In the following description, please refer to FIGS. 1, 2, 4, and 5 as appropriate.

FIG. 6 is a flowchart showing the procedure of fuel supply control according to this embodiment. When executing the fuel supply control according to this embodiment, the control condition determination unit 21 included in the fuel supply control device 20 determines whether or not to shift to the fuel supply control according to the first embodiment (step S501). . The condition for entering this control is, for example, when the engine ECU 30 is learning the fuel injection amount or when the A / F feedback of the exhaust gas by the O ₂ sensor 46 is not possible. The learning of the fuel injection amount is executed to correct the fuel injection amount of the fuel injection valve 3 that has changed due to secular change. The case where the A / F feedback of the exhaust gas cannot be performed by the O ₂ sensor 46 is, for example, a case where the O ₂ sensor 46 is out of order immediately after the start of the internal combustion engine 1 and before the warm-up is completed.

If the fuel supply control according to this embodiment is executed when the A / F feedback of the exhaust gas cannot be performed by the O ₂ sensor 46, the variation in the fuel injection amount due to the temperature characteristics of the fuel injection valve 3 can be suppressed. Thereby, since the change of the shift | offset | difference of fuel injection amount is suppressed and the internal combustion engine 1 can be drive | operated under set A / F, the deterioration of an emission can also be suppressed. Further, if the fuel supply control according to this embodiment is executed while the engine ECU 30 is learning the fuel injection amount, there is a risk that the fuel injection amount due to the temperature characteristic of the fuel injection valve 3 will be erroneously learned. Can be reduced.

  Thus, if the fuel supply control according to this embodiment is executed under conditions necessary to avoid the influence due to the temperature characteristics of the fuel injection valve 3, the driving force of the internal combustion engine 1 driven by the high-pressure pump 10 is achieved. Loss can be reduced. When the fuel is returned from the relief valve 11 or the electromagnetic relief valve 14 to the fuel tank 26, the fuel temperature in the fuel tank 26 rises. However, if the fuel supply control according to this embodiment is executed under conditions necessary to avoid the influence due to the temperature characteristics of the fuel injection valve 3, and otherwise the normal fuel supply control is performed, the fuel tank 26 The rise of the fuel temperature inside can be suppressed. Thereby, deterioration of the evaporation emission can be suppressed.

  When the control condition determination unit 21 determines not to shift to the fuel supply control according to this embodiment (step S501; No), the fuel supply control according to this embodiment ends. When the control condition determination unit 21 determines to shift to fuel supply control (step S501; Yes), the fuel amount determination unit 22 determines the amount of fuel to be supplied to the delivery pipe 2. First, the fuel amount determination unit 22 acquires the intake air temperature Ti and the coolant temperature Tw from the intake air temperature sensor 45 and the coolant temperature sensor 44 (step S502).

  The amount of heat transferred from the internal combustion engine 1 to the fuel in the delivery pipe 2 is proportional to the difference between the temperature of the internal combustion engine and the fuel temperature in the delivery pipe 2. Here, the temperature of the internal combustion engine is represented by the coolant temperature Tw, and the fuel temperature in the delivery pipe 2 is represented by the intake air temperature Ti. The fuel amount determination unit 22 obtains a temperature difference ΔT between the acquired intake air temperature Ti and the water temperature Tw (step S503). Here, ΔT = | Tw−Ti |. This is a parameter representing the amount of heat transferred from the internal combustion engine 1 to the delivery pipe 2. The intake air temperature Ti and the coolant temperature Tw can be measured by the existing intake temperature sensor 45 and the coolant temperature sensor 44. Therefore, by expressing the amount of heat transferred from the internal combustion engine 1 to the delivery pipe 2 as a temperature difference ΔT between the intake air temperature Ti and the water temperature Tw, these can be measured using existing sensors, so it is necessary to provide separate sensors. Absent. Thereby, the structure of the fuel supply apparatus 50 can be simplified.

Based on this temperature difference ΔT, the amount of fuel supplied to the delivery pipe 2 is determined. Specifically, the fuel supply amount Q _H discharged from the high-pressure pump 10 to the delivery pipe 2 is determined (step S504). Then, the high-pressure pump 10 discharges the fuel to the delivery pipe 2 with the fuel supply amount Q _H (step S505). Note that the amount of fuel supplied to the delivery pipe 2 is set to be larger than the amount injected from the fuel injection valve 3, and the surplus is discharged from the relief valve 11 or the electromagnetic relief valve 14. Thereafter, the process returns to step S501 and the operation state of the internal combustion engine 1 is monitored.

  FIG. 7 is an explanatory diagram illustrating an example of a flow rate determination map of the high-pressure pump. The flow rate of the high-pressure pump 10 can be obtained by giving the temperature difference ΔT to the flow rate determination map 70 shown in FIG. The temperature difference ΔT increases, that is, the amount of heat transferred from the internal combustion engine 1 to the fuel in the delivery pipe 2 increases, and the flow rate of the high-pressure pump 10 is increased to increase the amount of fuel supplied to the delivery pipe 2. . By determining the flow rate of the high-pressure pump 10 in this way, the fuel temperature in the delivery pipe 2 can be maintained within a predetermined range regardless of the load of the internal combustion engine 1.

  FIGS. 8A and 8B are explanatory diagrams illustrating the relationship between the fuel injection amount of the fuel injection valve and the deviation amount of the fuel injection amount of the fuel injection valve according to the conventional fuel supply control. In the conventional fuel supply control that does not consider heat transfer from the internal combustion engine to the delivery pipe, when the fuel injection amount of the fuel injection valve increases, the temperature of the fuel supplied to the fuel injection valve decreases. As a result, the stroke of the fuel injection valve increases due to the difference in thermal expansion between the inside and the outside of the fuel injection valve. As a result, as shown in FIG. 8A, when the fuel injection amount of the fuel injection valve increases, the deviation ΔQi of the fuel injection amount of the fuel injection valve 3 is rich, that is, the fuel injection amount is larger than the set value. Change. This becomes more significant as the difference between the coolant temperature of the internal combustion engine and the intake air temperature increases.

  The fuel injection amount deviation ΔQi changes depending on the fuel injection amount of the fuel injection valve, that is, the load of the internal combustion engine. If the change in the fuel injection amount of the fuel injection valve is gradual, the fuel injection amount deviation ΔQi can be corrected by a control such as the engine ECU learning a correction value for the fuel injection amount. As a result, there is no A / F shift or emission deterioration caused by it. However, when the vehicle suddenly accelerates or decelerates, the fuel injection amount of the fuel injection valve changes rapidly.

For example, consider the case where the fuel injection amount of the fuel injection valve suddenly changes from a large state to a small state (change from Qi ₁ to Qi _{2 in} FIG. 8-2). At point a in FIG. 8-2, since the fuel injection amount is large, the stroke of the fuel injection valve is large, and the fuel injection amount deviation ΔQi is shifted to the rich side. When the fuel injection amount is Qi ₂ , the original fuel injection amount deviation ΔQi is the point c in FIG.

However, when the fuel injection amount suddenly changes to a small state (Qi ₂ ), immediately after the fuel injection amount changes, the difference ΔQi in the fuel injection amount shifts to the rich side from the original (FIG. 8-2). B point). This is because there is a delay in the temperature change of the fuel injection valve. Thereafter, the difference ΔQi in the fuel injection amount gradually changes to the point c. Thus, immediately after the fuel injection amount is changed, the fuel injection amount deviation ΔQi is shifted to the rich side from the original by (ΔQib−ΔQic). When the change in the fuel injection amount is abrupt, correction by the exhaust gas A / F feedback cannot completely correct the change in the fuel injection amount deviation ΔQi. For this reason, the A / F in the combustion chamber becomes rich, and this causes the emission to deteriorate.

  FIG. 9 is an explanatory diagram showing the relationship between the fuel injection amount of the fuel injection valve and the deviation amount of the fuel injection amount of the fuel injection valve when the fuel supply control according to this embodiment is used. The fuel injection amount of the fuel injection valve 3 increases as the load on the internal combustion engine 1 increases. In the fuel supply control according to this embodiment, the amount of fuel supplied to the delivery pipe 2 is changed based on the amount of heat transferred from the internal combustion engine 1 to the fuel in the delivery pipe 2. More specifically, fuel is supplied to the delivery pipe 2 regardless of the fuel injection amount of the fuel injection valve 3 based on the temperature difference ΔT between the intake air temperature and the coolant temperature. For this reason, the fuel temperature in the delivery pipe 2 can be kept within a predetermined range regardless of the fuel injection amount of the fuel injection valve 3, that is, the load of the internal combustion engine 1.

  Thereby, the fuel whose temperature is maintained within the predetermined range is supplied to the fuel injection valve 3. As a result, as shown in FIG. 9, it is possible to suppress the change in the fuel injection amount of the fuel injection valve 3, that is, the deviation ΔQi of the fuel injection amount of the fuel injection valve 3 caused by the load fluctuation of the internal combustion engine 1. Thereby, the dispersion | variation in the fuel injection quantity resulting from the temperature characteristic of the fuel injection valve 3 can be suppressed. Note that the deviation ΔQi of the fuel injection amount of the fuel injection valve 3 changes due to the temperature change of the cooling water of the internal combustion engine 1. However, since the temperature change of the cooling water of the internal combustion engine 1 is gradual, the fuel injection amount deviation ΔQi can be corrected by the control such as the engine ECU 30 learning the correction value of the fuel injection amount.

  Further, since the amount of fuel supplied to the delivery pipe 2 is determined based on the amount of heat transferred from the internal combustion engine 1 to the fuel in the delivery pipe 2, an amount necessary and sufficient to avoid the influence of the temperature characteristics of the fuel injection valve 3. You can only supply fuel. Thereby, the driving force loss of the internal combustion engine 1 due to the driving of the high-pressure pump 10 can be reduced. In addition, since the amount of fuel returning to the fuel tank 26 can be suppressed, an increase in the fuel temperature in the fuel tank 26 can be suppressed. Thereby, deterioration of the evaporation emission can be suppressed.

  As described above, the fuel supply device and the fuel supply control device according to the present invention are useful for an internal combustion engine that directly injects fuel into a cylinder, and in particular, variations in the fuel injection amount due to the temperature characteristics of the fuel injection valve. It is suitable for suppressing.

It is sectional drawing of one cylinder with which the internal combustion engine which concerns on this Example is provided. It is a conceptual diagram which shows an example of the fuel supply apparatus which concerns on this Example. It is explanatory drawing showing operation | movement of the high pressure pump which concerns on this Example. It is explanatory drawing showing operation | movement of the high pressure pump which concerns on this Example. It is explanatory drawing showing operation | movement of the high pressure pump which concerns on this Example. It is explanatory drawing showing operation | movement of the high pressure pump which concerns on this Example. It is a conceptual diagram which shows the other example of the fuel supply apparatus used for the internal combustion engine which concerns on this Example. It is explanatory drawing which shows the fuel supply control apparatus which concerns on this Example. It is a flowchart which shows the procedure of the fuel supply control which concerns on this Example. It is explanatory drawing which shows an example of the flow volume determination map of a high pressure pump. It is explanatory drawing which shows the relationship between the fuel injection quantity of the fuel injection valve by the conventional fuel supply control, and the deviation | shift amount of the fuel injection quantity of a fuel injection valve. It is explanatory drawing which shows the relationship between the fuel injection quantity of the fuel injection valve by the conventional fuel supply control, and the deviation | shift amount of the fuel injection quantity of a fuel injection valve. It is explanatory drawing which shows the relationship between the fuel injection quantity of a fuel injection valve at the time of using the fuel supply control which concerns on this Example, and the deviation | shift amount of the fuel injection quantity of a fuel injection valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 1s Cylinder 2 Delivery pipe 3 Fuel injection valve 10 High pressure pump 11 Relief valve 12 Feed pump 13 Camshaft 14 Electromagnetic relief valve 20 Fuel supply control apparatus 21 Control condition determination part 22 Fuel amount determination part 30 Engine ECU
44 Cooling water temperature sensor 45 Intake air temperature sensor 50, 50 'Fuel supply device 51 Catalyst 70 Flow rate determination map

Claims (9)

Supplying fuel to an internal combustion engine,
A delivery pipe that is attached to the internal combustion engine and stores fuel supplied from the fuel pressure feeding means;
A fuel injection valve attached to the delivery pipe for injecting fuel supplied from the delivery pipe into a cylinder of the internal combustion engine;
A relief valve for releasing excess fuel in the delivery pipe,
A fuel supply device that changes the amount of fuel supplied to the delivery pipe based on the amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe.   The fuel supply device according to claim 1, wherein the amount of fuel supplied to the delivery pipe is increased as the amount of heat increases.   3. The fuel supply device according to claim 1, wherein the amount of heat is a difference between a water temperature of cooling water for cooling the internal combustion engine and an intake air temperature of air taken in by the internal combustion engine. 4.   The fuel supply device according to any one of claims 1 to 3, wherein the relief valve has a fuel pressure adjustment function capable of changing a pressure of fuel in the delivery pipe.   When the control device that controls the operation of the internal combustion engine learns the correction value of the fuel injection amount injected from the fuel injection valve, or at least when the air-fuel ratio feedback of the exhaust gas of the internal combustion engine cannot be performed 5. The fuel supply device according to claim 1, wherein an amount of fuel supplied to the delivery pipe is adjusted based on the amount of heat under conditions. Control of a fuel supply device having a delivery pipe for storing fuel to be supplied to an internal combustion engine, and a fuel injection valve attached to the delivery pipe and for injecting fuel supplied from the delivery pipe into the cylinder of the internal combustion engine Used for
A fuel supply comprising a fuel amount determination unit that determines the amount of fuel by changing an amount of fuel supplied to the delivery pipe based on an amount of heat transferred from the internal combustion engine to the fuel in the delivery pipe. Control device.   The fuel supply control device according to claim 6, wherein the fuel amount determination unit determines the amount of the fuel so that the amount of fuel supplied to the delivery pipe increases as the heat amount increases. .   The fuel supply control device according to claim 6 or 7, wherein the amount of heat is a difference between a water temperature of cooling water for cooling the internal combustion engine and an intake air temperature of air taken in by the internal combustion engine. Further, at least when the control device that controls the operation of the internal combustion engine learns a correction value of the fuel injection amount injected from the fuel injection valve, or when the air-fuel ratio feedback of the exhaust gas of the internal combustion engine is not possible A control condition determination unit that determines that one of the conditions is satisfied,
9. The fuel according to claim 6, wherein the fuel amount determination unit determines an amount of fuel to be supplied to the delivery pipe based on the heat amount when the condition is satisfied. Supply control device.

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