JP5733113B2 - Fuel supply device for internal combustion engine - Google Patents

Description

  The present invention relates to a fuel supply device for an internal combustion engine.

  In an internal combustion engine such as a diesel engine that injects high-pressure fuel into a cylinder, a common rail fuel supply device is frequently used. In this type of fuel supply device, high-pressure fuel is accumulated and stored in a common rail, and this high-pressure fuel is supplied to the fuel injection valves of the respective cylinders at an equal pressure. The fuel is brought to high pressure by two-stage compression of a feed pump and a high pressure pump. Further, the amount of suction into the high-pressure pump is controlled by a suction metering valve. The fuel pressure in the common rail is controlled by the intake metering valve so as to follow the target fuel pressure corresponding to the operating state of the engine.

  The high pressure pump is provided in the cylinder head cover. The high pressure pump includes a pressurizing chamber and a plunger. The pressurizing chamber is connected to the discharge pipe of the feed pump. The plunger reciprocates in the pressurizing chamber using the camshaft of the engine as a drive source, thereby pressurizing and discharging the fuel from the feed pump introduced into the pressurizing chamber.

  Here, since the plunger of the high-pressure pump is driven by the camshaft, it always reciprocates during operation of the engine. For this reason, during operation of the engine, the plunger of the high-pressure pump and the pressure chamber wall are heated by frictional heat. Further, since the high pressure pump is provided in the cylinder head cover, high heat of the engine body is easily conducted.

  Further, when no fuel is discharged from the high pressure pump as in fuel cut, the flow rate of fuel passing through the high pressure pump becomes zero. The fuel that passes through the high-pressure pump also serves to cool and lubricate the high-pressure pump. For this reason, when the fuel flow rate passing through the high-pressure pump becomes zero, the high-pressure pump is not sufficiently cooled, the temperature of the high-pressure pump rises, and the fuel temperature in the pipe rises.

  As a result, the temperature of the fuel in the high-pressure pump rises excessively, resulting in the generation of vapor and a decrease in fuel viscosity. When vapor is generated in the fuel, a so-called vapor lock phenomenon occurs in the fuel, and there is a possibility that the fuel cannot be supplied to the fuel injection valve at a desired pressure. Moreover, due to the decrease in the viscosity of the fuel, a sufficient lubricating oil film cannot be secured at the sliding part of the high-pressure pump, the sliding friction of the sliding part of the high-pressure pump increases, resulting in fuel consumption deterioration and increased wear, Problems such as seizure may occur.

  Therefore, a fuel supply device is known that is provided with a cooling fan that air-cools the high-pressure pump in order to suppress heating of the high-pressure pump (see, for example, Patent Document 1). The fuel supply device includes a temperature sensor that detects the temperature of the high-pressure pump, and a control circuit that drives the cooling fan when the temperature detected by the temperature sensor is equal to or higher than a predetermined temperature.

  According to this fuel supply device, for example, when the fuel is not supplied to the high pressure pump at the time of fuel cut or at the time of PFI operation in the dual injection system, and when the temperature of the high pressure pump exceeds a predetermined temperature, the control circuit Drive. As a result, the high-pressure pump is cooled by the cooling fan, and heating of the high-pressure pump is suppressed.

Special table 2003-515695 gazette

  However, in the conventional fuel supply device, the cooling fan is always driven when the temperature of the high-pressure pump exceeds a predetermined temperature. For this reason, even when the heating temperature of the high-pressure pump is slightly higher than the predetermined temperature and there is no need to output strong air from the cooling fan, air cooling may be performed sufficiently. As a result, a high load is applied to the cooling fan, and the life of the cooling fan is shortened.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a fuel supply device for an internal combustion engine that can extend the life of a cooling fan that cools a high-pressure pump.

  In order to achieve the above object, a fuel supply apparatus for an internal combustion engine according to the present invention includes (1) a feed pump that sucks, pressurizes and discharges fuel of the internal combustion engine, and sucks and pressurizes fuel discharged from the feed pump. At least one of the high-pressure pump and the cooling medium; the high-pressure pump that discharges the cooling medium; the cooling medium circulation means that circulates the cooling medium that can cool the high-pressure pump; the cooling medium temperature detection means that detects the temperature of the cooling medium; An internal combustion engine fuel supply device comprising: an electric cooling fan capable of cooling the air; and a control means for controlling the amount of fuel supplied from the feed pump to the high pressure pump and controlling the cooling fan. The control means is provided on the condition that supply of the fuel from the feed pump to the high-pressure pump is stopped while the internal combustion engine is being driven. To cool at least one of the high-pressure pump and the cooling medium to operate the fan, the temperature of said detected coolant by the coolant temperature detecting means is smaller air volume of the cooling fan as is at a low temperature.

  With this configuration, when the supply of fuel from the feed pump to the high-pressure pump is stopped by driving the internal combustion engine, for example, due to fuel cut or the like, the cooling fan is operated by the control means. The cooling fan cools at least one of the high-pressure pump and the cooling medium. When the cooling fan cools the cooling medium, the cooled cooling medium cools the high-pressure pump. For this reason, the cooling fan can cool the high-pressure pump directly or indirectly through the cooling medium. Thereby, it can suppress that the fuel which accumulated in the high-pressure pump turns into a vapor | steam because of high temperature.

  Here, when the temperature of the cooling medium is low, the cooling capacity of the high-pressure pump by the cooling medium is high, and therefore the degree of direct cooling of the high-pressure pump by the cooling fan can be lowered. For this reason, the air volume of a cooling fan is made small, so that the temperature of a cooling medium is low temperature. For this reason, the load of the cooling fan can be reduced as compared with the case where the cooling fan is continuously driven regardless of the temperature of the cooling medium as in the prior art. As a result, the life of the cooling fan can be extended, and maintenance and parts costs can be reduced.

  In the fuel supply device for an internal combustion engine according to (1), (2) the cooling medium circulation means is a cooling water circulation system that circulates cooling water to each part of the internal combustion engine, and the cooling medium includes: It is cooling water, and the cooling medium temperature detecting means is preferably a water temperature meter for measuring the temperature of the cooling water.

  With this configuration, when the cooling fan cools the cooling water, the cooled cooling water cools the high-pressure pump. For this reason, the cooling fan can cool the high-pressure pump directly or indirectly through the cooling water. Thereby, it can suppress that the fuel which accumulated in the high-pressure pump turns into a vapor | steam because of high temperature.

In the fuel supply device for an internal combustion engine according to (2 ) above, ( 3 ) the cooling fan is preferably a radiator fan that air-cools a radiator that cools the cooling water. With this configuration, by operating the cooling fan, the radiator is cooled to cool the cooling water, and air is taken into the engine room from the outside, so that the high-pressure pump and the internal combustion engine can be air-cooled.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel supply apparatus of the internal combustion engine which can aim at the lifetime improvement of the cooling fan which cools a high pressure pump can be provided.

1 is a schematic diagram showing a fuel supply device for an internal combustion engine according to an embodiment of the present invention. It is the schematic which shows the intake device and engine main body which concern on embodiment of this invention. It is the schematic which shows the fuel pumping part which concerns on embodiment of this invention. It is the schematic which shows the high pressure pump part which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the fuel supply apparatus of the internal combustion engine which concerns on embodiment of this invention. 3 is a time chart showing the operation of the fuel supply device for an internal combustion engine according to the embodiment of the present invention, in which the horizontal axis is the time axis, and (a) is whether fuel supply to the high-pressure pump unit is stopped or not. (B) shows the driving voltage supplied to the cooling fan, (c) shows the temperature of the cooling water, and (d) is measured when the fuel supply to the high-pressure pump unit is stopped. Counter C.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present embodiment, the present invention is applied to a fuel supply device for an internal combustion engine for a vehicle. The fuel supply device for an internal combustion engine according to the present embodiment is mounted on a dual injection internal combustion engine that uses both in-cylinder injection and port injection, for example, an in-line four-cylinder internal combustion engine.

  First, the configuration will be described.

  As shown in FIGS. 1 and 2, an internal combustion engine (hereinafter referred to as an engine) 1 includes an engine body 2, an intake device 3, an exhaust device 4, a fuel supply device 5, and a cooling device as cooling medium circulation means. 6 and an ECU (Electronic Control Unit) 7 as a control means.

  The engine body 2 includes a cylinder block 10 and a cylinder head 20. The cylinder block 10 and the cylinder head 20 include four cylinders 11. The cylinder 11 is provided with the vertical direction as the longitudinal direction.

  The cylinder block 10 includes a piston 12, a connecting rod 13, a crankshaft 14, and a crank angle sensor 15. The piston 12 is provided so as to reciprocate within the cylinder 11. The piston 12 is rotatably connected to the connecting rod 13. The connecting rod 13 is rotatably connected to the crankshaft 14. The crank angle sensor 15 measures the rotational speed of the crankshaft 14 and inputs it to the ECU 7.

  In the engine body 2, a combustion chamber 16 is formed by the cylinder block 10, the cylinder head 20, and the piston 12. The engine body 2 is configured to reciprocate the piston 12 by burning a mixture of fuel and air in the combustion chamber 16 at a desired timing, and to rotate the crankshaft 14 via the connecting rod 13.

  The cylinder head 20 includes an intake port 21, an intake valve 22, an intake camshaft (not shown), an exhaust port 23, an exhaust valve 24, an exhaust camshaft (not shown), and an ignition plug 25. The intake port 21 communicates the intake passage of the intake device 3 and the combustion chamber 16. The intake valve 22 opens and closes between the intake port 21 and the combustion chamber 16 by moving up and down, and controls the introduction of the intake air A from the intake passage of the intake device 3 to the combustion chamber 16. The intake camshaft moves the intake valve 22 up and down.

  The exhaust port 23 communicates the combustion chamber 16 and the exhaust passage of the exhaust device 4. The exhaust valve 24 opens and closes the combustion chamber 16 and the exhaust port 23 by raising and lowering, and controls the discharge of the exhaust gas G from the combustion chamber 16 to the exhaust passage of the exhaust device 4. The exhaust camshaft moves the exhaust valve 24 up and down.

  The intake valve 22 communicates the combustion chamber 16 with the intake passage when the valve is opened, and the exhaust valve 24 communicates the combustion chamber 16 with the exhaust passage when the valve is opened. When the piston 12 descends with the combustion chamber 16 communicating with the intake passage by opening the intake valve 22, the combustion chamber 16 can suck the intake air A through the intake passage. Further, when the piston 12 rises in a state where the combustion chamber 16 communicates with the exhaust passage by opening the exhaust valve 24, the combustion chamber 16 can exhaust the exhaust gas G through the exhaust passage.

  The spark plug 25 is provided in the combustion chamber 16 so as to be capable of spark ignition. The ignition plug 25 is configured so that the ignition timing is controlled by the ECU 7.

  The intake device 3 includes an intake pipe 30, an air cleaner 31, an intake pipe 32, an aero flow meter 33, a throttle valve 34, a surge tank 35, and an intake manifold 36. The air cleaner 31 is cleaned by removing dust and the like from the intake air A with a filter at an upstream portion of the intake device 3. The aero flow meter 33 detects the intake flow rate of the intake air A.

  The throttle valve 34 is provided between the air cleaner 31 and the surge tank 35 and adjusts the intake flow rate of the intake air A supplied to each cylinder 11 by electronic control. The intake manifold 36 connects the intake pipe 32 and each cylinder 11.

  The intake air A is distributed from the intake pipe 30 in the order of air cleaner 31 → throttle valve 34 → surge tank 35 → intake manifold 36 and flows into each cylinder 11. Further, the engine body 2 and the intake device 3 are connected by the connection between the intake manifold 36 and each cylinder 11.

  The exhaust device 4 includes an exhaust manifold 40, an exhaust gas pipe 41, and an exhaust after-treatment device (not shown).

  The exhaust manifold 40 circulates the exhaust gas G discharged from each cylinder 11. By connecting the exhaust manifold 40 and each cylinder 11, the engine body 2 and the exhaust device 4 are connected. The exhaust gas pipe 41 connects the exhaust manifold 40 and the exhaust aftertreatment device.

  The fuel supply device 5 includes a fuel supply mechanism 50 and a relief mechanism 70. The fuel supply mechanism 50 includes a fuel pump 51, a low-pressure fuel pipe 52, a low-pressure delivery pipe 53, a low-pressure injector 54, a high-pressure pump 55, a high-pressure fuel pipe 56, and a high-pressure delivery pipe 58. And a high-pressure side injector 59. The fuel supply mechanism 50 is configured to pump and supply fuel to the engine body 2.

  As shown in FIG. 3, the fuel pump 51 includes a fuel tank 511, a feed pump unit 512, a suction filter 513, a fuel filter 514, a fuel pressure control valve 515, a jet pump 516, and a fuel that connects them. A tube 517.

  The fuel tank 511 stores fuel consumed by the engine body 2, for example, gasoline. The fuel tank 511 is bowl-shaped and includes a first fuel storage unit 511a and a second fuel storage unit 511b. A sub tank 511c is provided inside the first fuel storage unit 511a. A part of the fuel pumping unit 51 is disposed in the sub tank 511c. Here, in this specification, the fuel tank 511 is used in a general sense including the sub tank 511c. For example, the fuel stored in the fuel tank 511 includes the fuel stored in the sub tank 511c. And

  The feed pump unit 512 is disposed in the sub tank 511c, and includes, for example, a feed pump 512a having an impeller for operating the pump, a pump drive motor 512b that is a built-in DC motor that rotationally drives the feed pump 512a, and a check (not shown) And a valve. The feed pump 512a is driven and stopped by ON / OFF control of energization to the pump drive motor 512b based on the ON / OFF command signal transmitted from the ECU 7.

  The feed pump 512a can pump up the fuel from the fuel tank 511 by driving the pump drive motor 512b, and pressurize the pumped fuel to a pressure within a constant variable range of, for example, less than 1 [MPa] and discharge the fuel. Yes. Further, the feed pump 512a can change the discharge amount and discharge pressure per unit time by changing the rotational speed [rpm] of the pump drive motor 512b with respect to the same supply voltage under the control of the ECU 7. . Alternatively, the feed pump 512a can change the discharge amount and discharge pressure per unit time by changing the rotation speed of the pump drive motor 512b in response to the change in the supply voltage.

  That is, the feed pump 512a is capable of variably controlling the discharge amount and discharge pressure per unit time by the ON / OFF drive and the rotational speed control of the feed pump 512a. The feed pump 512a is a variable fuel pump or a variable fuel pressure pump capable of increasing at least one of a fuel supply flow rate and a supply pressure through supply pipes such as the low-pressure delivery pipe 53 and the high-pressure delivery pipe 58. Yes.

  The check valve is a check valve provided at the discharge portion of the feed pump 512a. The check valve opens in the fuel supply direction from the feed pump 512a to the low-pressure side fuel pipe 52, and closes in the reverse flow direction of fuel from the low-pressure side fuel pipe 52 to the feed pump 512a. As a result, the check valve prevents the backflow of the pressurized fuel.

  The suction filter 513 is provided at the suction port of the feed pump unit 512, and prevents suction of foreign matter. The fuel filter 514 is provided at the discharge port of the feed pump unit 512 and removes foreign matters in the discharged fuel.

  The fuel pressure control valve 515 includes a diaphragm (not shown) that receives the pressure of the fuel discharged from the feed pump unit 512 in the valve opening direction, and a compression coil spring (not shown) that urges the diaphragm in the valve closing direction. The fuel pressure control valve 515 opens when the pressure of the fuel received by the diaphragm exceeds the set pressure, and maintains the closed state while the pressure of the fuel received by the diaphragm does not reach the set pressure. Thereby, the fuel pressure control valve 515 adjusts the pressure of the fuel discharged into the low pressure side fuel pipe 52 to a preset low pressure side supply pressure, for example, 400 [kPa].

  The jet pump 516 is a known one that introduces fuel from the second fuel reservoir 511b to the sub tank 511c by surplus fuel discharged into the fuel tank 511 by the fuel pressure control valve 515.

  As shown in FIGS. 1 and 2, the low-pressure side fuel pipe 52 includes a pipe that connects the fuel pumping unit 51 to the low-pressure side delivery pipe 53. However, the low-pressure side fuel pipe 52 is an arbitrary member that forms a fuel passage, and is not limited to a fuel pipe. One member through which the fuel passage is formed or a fuel passage between the members is formed. A plurality of members may be formed.

  The low-pressure delivery pipe 53 is connected to the low-pressure fuel pipe 52 at one end of the cylinder 11 in the series arrangement direction. A low-pressure injector 54 is connected to the low-pressure delivery pipe 53 at the same interval as the cylinder 11 in the series arrangement direction of the cylinders 11. The low-pressure delivery pipe 53 distributes the fuel from the fuel pumping unit 51 to each low-pressure injector 54 at an equivalent pressure.

  The low pressure side injector 54 is provided as a port injection injector with the injection hole portion 54 a exposed in the intake port 21 corresponding to each cylinder 11. The low pressure side injector 54 is opened by an electromagnetic valve portion (not shown) driven by an injection command signal from the ECU 7 and a valve opening operation to inject fuel into the intake port 21 from the injection hole portion 54a when energizing the electromagnetic valve portion. It consists of a fuel injection valve provided with a nozzle part that does not. When any one of the plurality of low-pressure injectors 54 opens, the pressurized fuel in the low-pressure delivery pipe 53 is injected into the intake port 21 from the injection hole portion 54a of the low-pressure injector 54. It has become.

  As shown in FIG. 4, the high-pressure pump unit 55 includes an upstream pipe 80, a downstream pipe 81, a pulsation damper 82, a high-pressure pump body 83, and an electromagnetic spill valve 84. The high-pressure pump unit 55 is attached to the upper side of the cylinder head 20 and is connected between the low-pressure side fuel pipe 52 and the high-pressure side fuel pipe 56. The upstream side pipe 80 is connected to the branch pipe 52 a of the low pressure side fuel pipe 52. The downstream side pipe 81 is connected to the high pressure side fuel pipe 56.

  The pulsation damper 82 is provided in the upstream pipe 80, and has an elastic diaphragm 82a that receives the fuel pressure, and a compression coil spring 82b. The pulsation damper 82 changes the internal volume by elastic deformation of the diaphragm 82a and suppresses the pressure pulsation of the fuel in the upstream pipe 80.

  The high-pressure pump main body 83 includes a pump housing 831, a plunger 832, a cam shaft 833, a follower lifter 834, and a return spring 835.

  The pump housing 831 includes a cylindrical pressurizing chamber 831a formed inside, a fuel introduction port portion 831b, and a fuel discharge port portion 831c. The fuel introduction port portion 831b is connected to the downstream end of the upstream side pipe 80 and introduces fuel from the branch pipe 52a of the low pressure side fuel pipe 52 into the pressurizing chamber 831a. The fuel discharge port 831c is connected to the upstream end of the downstream pipe 81 and discharges fuel from the pressurizing chamber 831a to the high-pressure fuel pipe 56.

  The plunger 832 has a cylindrical shape and is slidably provided in the pump housing 831. The plunger 832 changes the volume of the pressurizing chamber 831a by sliding. The camshaft 833 is provided at one end of the exhaust camshaft of the engine body 2 and has a cam 833a at the end. The follower lifter 834 is integrated with the plunger 832, and the plunger 832 is slid by being pressed by the cam 833a. The return spring 835 is a compression coil spring provided between the pump housing 831 and the follower lifter 834, and urges the follower lifter 834 toward the cam 833a.

  In the high-pressure pump body 83, the pressurizing chamber 831 a defined by the pump housing 831 and the plunger 832 changes its volume by the reciprocating movement of the plunger 832, thereby sucking and pressurizing fuel from the feed pump unit 512. And a discharge operation. In other words, the high-pressure pump main body 83 sucks fuel pressurized by the feed pump 512a from the fuel introduction port portion 831b and discharges it from the fuel discharge port portion 831c. When the high-pressure pump main body 83 is operated, the fuel is pressurized in the pressurizing chamber 831a and discharged from the fuel discharge port portion 831c.

  In addition, since the cam 833a is provided on the camshaft 833, the plunger 832 reciprocates while the engine 1 is operating even when the fuel is not fed into the pressurizing chamber 831a.

  The high-pressure pump main body 83 pressurizes the fuel introduced into the pressurizing chamber 831a from the low-pressure side fuel pipe 52 from, for example, about 400 [kPa] to, for example, about 4 [MPa] to 13 [MPa]. It discharges to the pipe 56.

  The electromagnetic spill valve 84 includes a valve body 841, an electromagnetic drive coil 842, and a pressing spring 843. The electromagnetic spill valve 84 is provided in the fuel introduction port portion 831 b of the high-pressure pump main body 83.

  The valve body 841 has a substantially cylindrical shape, and includes a valve body main body portion 841a and an iron core portion 841b. The valve body main body 841a is formed at an end portion of the valve body 841 located inside the pressurizing chamber 831a, and is formed in a poppet valve body shape capable of opening and closing the fuel introduction port portion 831b. The iron core portion 841b is formed at an end portion of the valve body 841 located outside the pressurizing chamber 831a, and is inserted along the longitudinal direction into the central portion of the electromagnetic drive coil 842.

  The valve body 841 is slidably provided with respect to the pump housing 831. The valve body body 841a is closed by being pressed by the fuel introduction port portion 831b, and the valve body main body portion 841a is fuel-introduced. The valve is opened by being separated from the port portion 831b. The electromagnetic drive coil 842 is energized by the ECU 7 to electromagnetically drive the valve body 841. The pressing spring 843 is composed of a compression coil spring, and always biases the valve body 841 in the valve opening direction.

  The valve body 841 opens so as to introduce the fuel fed from the feed pump 512a into the pressurizing chamber 831a when the electromagnetic drive coil 842 is in a non-excited state. In addition, the valve body 841 is configured to perform a valve closing operation so that the high pressure pump main body 83 can be pressurized and discharged when the electromagnetic drive coil 842 is driven to be excited.

  When the electromagnetic spill valve 84 is closed in response to an input signal from the ECU 7, the electromagnetic spill valve 84 has a check valve function for preventing a high-pressure backflow. Further, when the electromagnetic spill valve 84 is opened in response to an input signal from the ECU 7, the suction of fuel into the pressurizing chamber 831a or the low pressure side fuel piping 52 of the fuel in the pressurizing chamber 831a is performed according to the displacement of the plunger 832. It is designed to allow leakage into

  The electromagnetic spill valve 84 closes the fuel introduction port portion 831b with the valve body 841 when the electromagnetic drive coil 842 is excited. The electromagnetic spill valve 84 sucks fuel into the pressurizing chamber 831a, pressurizes the fuel in the pressurizing chamber 831a, and pressurizes by the volume change of the pressurizing chamber 831a due to the reciprocating movement of the plunger 832. The fuel is discharged from the chamber 831a.

  The high-pressure side fuel pipe 56 is composed of a pipe connecting the high-pressure pump unit 55 to the high-pressure side delivery pipe 58 and includes a check valve 57 in the middle. The high-pressure side fuel pipe 56 is an arbitrary member that forms a fuel passage, and is not limited to a fuel pipe. One member through which the fuel passage is formed or a fuel passage is formed between the members. A plurality of members may be used.

  The check valve 57 is provided in the vicinity of the high-pressure pump unit 55 and has a valve body 571 and a compression coil spring 572. The check valve 57 opens when the fuel pressure on the high-pressure pump unit 55 side becomes larger than the fuel pressure on the high-pressure injector 59 side with a significant differential pressure of about 100 [kPa], for example, while the high-pressure pump unit 55 When the pressure on the side is substantially equal to or smaller than the pressure on the high pressure side injector 59 side, the valve is closed.

  As shown in FIG. 1, the high-pressure delivery pipe 58 is connected to the high-pressure fuel pipe 56 on one end side in the series arrangement direction of the cylinders 11. A high pressure side injector 59 is connected to the high pressure side delivery pipe 58 at the same interval as the cylinder 11 in the series arrangement direction of the cylinders 11. As a result, the high-pressure delivery pipe 58 distributes the fuel from the high-pressure pump unit 55 to each high-pressure injector 59 at an equivalent pressure. The high-pressure delivery pipe 58 is equipped with a fuel pressure sensor 58a that detects the internal fuel pressure.

  The high-pressure injector 59 is provided as an in-cylinder injector with the injection hole portion 59a exposed in the combustion chamber 16 of each cylinder 11. The high-pressure side injector 59 is opened by an electromagnetic valve portion (not shown) driven by an injection command signal from the ECU 7 and a valve opening operation to inject fuel into the combustion chamber 16 from the injection hole portion 59a when the electromagnetic valve portion is energized. It consists of a fuel injection valve provided with a nozzle part that does not. When any one of the plurality of high-pressure injectors 59 opens, the pressurized fuel in the high-pressure delivery pipe 58 is injected into the combustion chamber 16 from the injection hole portion 59a of the high-pressure injector 59. It has become.

  The relief mechanism 70 includes a low pressure side relief portion 71 and a high pressure side relief portion 72.

  The low-pressure side relief portion 71 includes a low-pressure side relief pipe 71a and a low-pressure side electromagnetic relief valve 71b. The low pressure side relief pipe 71 a is piped between the fuel tank 511 and the end of the low pressure side delivery pipe 53 opposite to the end to which the low pressure side fuel pipe 52 is connected. The low-pressure side electromagnetic relief valve 71b is provided in the middle of the low-pressure side relief pipe 71a, and includes a valve body, an urging spring, and an electromagnetic operation unit (not shown).

  The valve body receives the fuel pressure in the low-pressure delivery pipe 53 as a pilot pressure. The urging spring normally urges the valve body in the valve closing direction and is compressed in the valve opening direction by the valve body when the pilot pressure reaches a preset pressure. The electromagnetic operating portion can urge the valve body in the valve opening direction similar to the pilot pressure against the urging force of the urging spring.

  The high pressure side relief portion 72 includes a high pressure side relief pipe 72a and a high pressure side electromagnetic relief valve 72b. The high-pressure side relief pipe 72 a is piped between the fuel tank 511 and the end of the high-pressure side delivery pipe 58 opposite to the end to which the high-pressure side fuel pipe 56 is connected. The high-pressure side electromagnetic relief valve 72b is provided in the middle of the high-pressure side relief pipe 72a, and includes a valve body (not shown), an urging spring, and an electromagnetic operation unit. Since the configuration of the high-pressure side electromagnetic relief valve 72b is the same as that of the low-pressure side electromagnetic relief valve 71b, detailed description thereof is omitted.

  The cooling device 6 includes a water pump 60, a water jacket 61, a radiator 62, a cooling fan 63, and a connection pipe 64. The water pump 60, the water jacket 61, and the radiator 62 are connected by a connection pipe 64. The cooling water W is circulated in the order of the water pump 60 → the water jacket 61 → the radiator 62 → the water pump 60.

  The water jacket 61 includes a cylinder block water jacket 61a formed on the cylinder block 10, a cylinder head water jacket 61b formed on the cylinder head 20, and a cooling water temperature sensor 61c as a cooling medium temperature detecting means. . The cylinder block water jacket 61 a and the cylinder head water jacket 61 b are connected to each other and provided around each cylinder 11. The water jacket 61 cools the engine body 2 by circulating the cooling water W therein.

  The radiator 62 cools the cooling water W by exchanging heat between the cooling water W and external air. For example, two cooling fans 63 are provided behind the radiator 62. Each cooling fan 63 includes a blade 63a and a drive motor 63b. The blades 63a are configured to send air backward by the rotation of the drive motor 63b. The drive motor 63b is controlled by the ECU 7.

  When the drive motor 63b is driven, the blades 63a are rotated, and air is sent backward. As a result, as indicated by arrows in the figure, outside air is circulated from the front to the rear of the radiator 62, and the radiator 62 is air-cooled. Further, the air after the radiator 62 is air-cooled is taken into the engine room, and the air-cooling of the engine body 2 and the high-pressure pump unit 55 is performed.

  The ECU 7 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores fixed data, a RAM (Random Access Memory) that temporarily stores data, and a rewritable nonvolatile memory. A backup memory, an input interface circuit having an A / D converter, a buffer, and the like, and an output interface circuit having a drive circuit and the like. The ECU 7 receives an ON / OFF signal of an ignition switch of the vehicle and is supplied with power from a battery (not shown).

  In accordance with a control program stored in advance in the ROM, the ECU 7 determines the basic injection amount required for each combustion based on the intake air amount detected by the aeroflow meter 33, the engine speed detected by the crank angle sensor 15, and the like. Is calculated. Further, the ECU 7 calculates a fuel injection amount subjected to various corrections and air-fuel ratio feedback corrections according to the operating state of the engine 1 based on the basic injection amount and set value information stored in advance in a backup memory. It is like that. Furthermore, the ECU 7 outputs an injection command signal to the low-pressure injector 54 and the high-pressure injector 59, a valve drive instruction signal for driving the electromagnetic spill valve 84, and the like based on the calculated fuel injection amount. It has become.

  The ECU 7 adjusts the amount of fuel leaked from the pressurizing chamber 831 a to the low-pressure side fuel pipe 52 by the electromagnetic spill valve 84. The ECU 7 can control the pressure of the fuel supplied from the high-pressure pump main body 83 to the high-pressure delivery pipe 58 to an optimum fuel pressure according to the operating state of the engine 1 and the injection characteristics of the high-pressure injector 59 by at least this adjustment. It has become.

  For example, the ECU 7 can set an ON time during which the electromagnetic drive coil 842 of the electromagnetic spill valve 84 is in an excited state and an OFF time during which the excited state is released within a certain signal period. The ECU 7 adjusts the amount of leakage of fuel from the pressurizing chamber 831a by the electromagnetic spill valve 84 by changing the ratio of ON time (0% to 100%; hereinafter referred to as duty ratio) within the signal period. be able to.

  In addition, the ECU 7 first performs fuel injection by the low-pressure injector 54 when the engine 1 is started. The ECU 7 can reach the fuel pressure level required for fuel injection by the high-pressure injector 59 when the fuel pressure in the high-pressure delivery pipe 58 detected by the fuel pressure sensor 58a exceeds a preset pressure value. It comes to judge that it was in a state. Based on this determination, the ECU 7 starts outputting an injection command signal to the high pressure side injector 59.

  Further, the ECU 7 is based on the in-cylinder injection from the high-pressure side injector 59, for example. The port injection is used together under the operating condition. Alternatively, the ECU 7 performs port injection from the low pressure side injector 54 at the time of high rotation and high load in which port injection is effective, for example, based on in-cylinder injection from the high pressure side injector 59, for example. Alternatively, the ECU 7 is configured to perform an operation (hereinafter referred to as a PFI operation) in which the engine 1 is only in port injection without in-cylinder injection.

  In addition, the ECU 7 stops the energization of the electromagnetic drive coil 842 of the electromagnetic spill valve 84 when, for example, the accelerator is turned off while the vehicle is traveling at a high speed, and the high-pressure pump unit 55 cannot perform the pressurizing operation. It is supposed to be in a state.

  Here, the high-pressure pump unit 55, the cooling fan 63, and the ECU 7 in the present embodiment constitute a fuel supply device for an internal combustion engine of the present invention.

  Next, the operation will be described.

  The flowchart shown in FIG. 5 is a program for a fuel supply process for an internal combustion engine that is executed by the CPU of the ECU 7 using the RAM as a work area. The program for the fuel supply process for the internal combustion engine is stored in the ROM of the ECU 7.

  In the fuel supply device 5 of the present embodiment configured as described above, the fuel supply process of the internal combustion engine is executed at predetermined time intervals (for example, 10 ms) by the ECU 7. .

As shown in FIG. 5, the ECU 7 determines whether or not a fuel cut (F / C) is performed in the high-pressure pump unit 55 of the fuel supply device 5 (step S1). When the ECU 7 determines that the fuel cut is not performed in the high pressure pump unit 55 of the fuel supply device 5 (step S1; NO), it determines whether or not the engine 1 is performing the PFI operation (step 2). . When the ECU 7 determines that the engine 1 is not performing the PFI operation (step S2; NO), the ECU 7 sets the flag F to 0 (step S3). Step S3 is a process in t ₀ in the time chart shown in FIG. 6 (a), for example.

  On the other hand, when the ECU 7 determines that the fuel cut is being performed in the high-pressure pump unit 55 of the fuel supply device 5 (step S1; YES), or when the engine 1 determines that the PFI operation is being performed (step S1). S2; YES), the ECU 7 determines that fuel is not supplied to the high-pressure pump unit 55. At this time, the fuel is not supplied to the pressurizing chamber 831a of the high-pressure pump main body 83, and the plunger 832 reciprocates. For this reason, since friction is generated without supplying fuel between the plunger 832 and the pump housing 831, the high-pressure pump main body 83 easily generates heat.

Then, the ECU 7 determines whether or not the flag F is 1 (step S4). When the ECU 7 determines that the flag F is not 1 (step S4; NO), the ECU 7 sets the flag F to 1 (step S5). Processing in step S5, for example, a process in the t ₁ in the time chart shown in Figure 6 (a). Further, ECU 7 sets the _{C 0} which sets the counter C in advance (step S6). The process of step S6, for example, a process in the t ₁ in the time chart shown in FIG. 6 (d).

Then, ECU 7 is, when set to _{C 0} is set to the counter C in advance (step S6), and or when the flag F is judged to be 1 (Step S4; YES), ECU 7 is the temperature of the cooling water W in advance or higher than the set the high temperature side threshold value T _H whether the judged (step S7).

ECU 7 is, when the temperature of the cooling water W was determined to be higher than the high temperature side threshold _{T H} (step S7; YES), ECU 7 the high side drive voltage value _{V H} of the drive voltage is set in advance of the cooling fan 63 Set (step S8). Thereby, the cooling fan 63 is rotated at a high rotational speed. The processing when the temperature of the cooling water W is higher than the high temperature side threshold T _H is, for example, processing in the t ₁ in the time chart shown in FIG. 6 (c).

In this case, the temperature of the cooling water W is higher than the high temperature side threshold T _H, the cooling water W flowing through the cylinder head water jacket 61b is not able to sufficiently cool the cylinder head 20, as a result, the high-pressure pump The part 55 is also difficult to be cooled. On the other hand, the cooling water W is cooled in the radiator 62 when the cooling fan 63 rotates at a high rotational speed. Then, the cooled cooling water W flows through the cylinder head water jacket 61b, whereby the cylinder head 20 is cooled and the high-pressure pump unit 55 is also cooled.

  The high-pressure pump unit 55 is also cooled by air taken into the engine room from the cooling fan 63. This suppresses the high-pressure pump unit 55 from being heated, so that the fuel staying in the high-pressure pump unit 55 during the fuel cut is prevented from becoming vapor due to heat.

On the other hand, ECU 7 is, when the temperature of the cooling water W was judged to not higher than the high temperature side threshold _{T H} (step S7; NO), ECU 7 reduces the counter C by 1 (Step S9). Process when the temperature of the cooling water W is not higher than the high temperature side threshold T _H is, for example, processing in t ₂ at the time chart shown in FIG. 6 (d).

The ECU 7 determines whether or not the counter C exceeds 0 (step S10). ECU 7 is, when it is determined that the counter C is greater than zero (Step S10; YES), ECU 7 is set to the high drive voltage value _{V H} which is set a driving voltage of the cooling fan 63 in advance (step S8 ). Thereby, the cooling fan 63 is rotated at a high rotational speed. The processing when the counter C is greater than zero, for example, a t ₂ in the time chart shown in FIG. 6 (d) and the processing in the t _3.

When the ECU 7 determines that the counter C does not exceed 0 (step S10; NO), the ECU 7 determines whether or not the temperature of the cooling water W is higher than a preset low temperature side threshold value _TL (step S11). ).

When the ECU 7 determines that the temperature of the cooling water W is higher than the low temperature side threshold _TL (step S11; YES), the ECU 7 sets the driving voltage of the cooling fan 63 to the preset high side driving voltage value _VH . Set (step S8). Thereby, the cooling fan 63 is rotated at a high rotational speed. Process when the temperature of the cooling water W is higher than the low temperature side threshold T _L is made of, for example, t ₂ in the time chart shown in FIG. 6 (c) and processing in t _a.

When the ECU 7 determines that the temperature of the cooling water W is not higher than the low temperature side threshold _TL (step S11; NO), the ECU 7 sets the drive voltage of the cooling fan 63 to 0 (step S12). Thereby, the driving of the cooling fan 63 is stopped. Process when the temperature of the cooling water W is not higher than the low temperature side threshold T _L, for example a process in t ₃ of the time chart shown in FIG. 6 (c) and FIG. 6 (d).

At this time, since the temperature of the cooling water W is equal to or lower than the low temperature side threshold _TL , the high-pressure pump unit 55 is sufficiently cooled by the cooling water W flowing through the cylinder head water jacket 61b. Further, since the counter C has decreased to 0 or less, a sufficient time has elapsed since the temperature of the cooling water W has decreased to the high temperature side threshold value _TH or less. For this reason, although the oil temperature of the lubricating oil is not directly detected, the lubricating oil is also sufficiently cooled. Therefore, even if the cooling fan 63 is not rotating, the high-pressure pump unit 55 is prevented from being heated, so the fuel staying in the high-pressure pump unit 55 during the fuel cut becomes heat vapor. It is prevented.

Here, in order for the ECU 7 to set the driving voltage of the cooling fan 63 to 0, the two conditions of the counter C being 0 or less and the temperature of the cooling water W being the low temperature side threshold _TL or less are satisfied. Only when That is, as shown by the solid line in FIG. 6 (c) and FIG. 6 (d), the before the counter C goes to zero or below, for example, when at t _a temperature of the cooling water W is equal to or less than the low temperature side threshold value T _L is The ECU 7 sets the drive voltage of the cooling fan 63 to 0 when the counter C becomes 0 or less. Further, as indicated by one-dot chain line in FIG. 6 (c) and FIG. 6 (d), the case where the temperature of the cooling water W before the following low-temperature side threshold T _L, the counter C in the example t _b becomes 0 or less The ECU 7 sets the drive voltage of the cooling fan 63 to 0 when the temperature of the cooling water W becomes equal to or lower than the low temperature side threshold _TL .

  As described above, according to the fuel supply device 3 according to the present embodiment, when the supply of fuel from the feed pump 512a to the high-pressure pump unit 55 is stopped due to, for example, a fuel cut during the driving of the engine 1, The cooling fan 63 is operated by the ECU 7. The cooling fan 63 cools the cooling water W by the radiator 62. The cooled cooling water W cools the cylinder head 20 and cools the high-pressure pump unit 55. Moreover, the cooling fan 63 air-cools the high-pressure pump part 55 by sending air into an engine room. Thereby, it can suppress that the fuel which accumulated in the pressurization chamber 831a of the high-pressure pump main body 83 turns into a vapor | steam because of high temperature.

Further, when the temperature of the cooling water W is a low temperature equal to or lower than the low temperature side threshold value _TL and the lubricating oil is at a low temperature due to the standby time using the counter C, the cooling fan 63 is stopped to eliminate the air volume Yes. For this reason, the load of the cooling fan 63 can be reduced as compared with the conventional case where the cooling fan is continuously driven regardless of the temperature of the cooling water W. As a result, the life of the cooling fan 63 can be extended, and maintenance and component costs can be reduced.

In the fuel supply device 3 for the internal combustion engine of the present embodiment described above, the driving voltage of the cooling fan 63 is set to the high-side driving voltage value V _H or two steps of 0. However, the fuel supply device for an internal combustion engine according to the present invention is not limited to this, and may change in multiple steps or steplessly according to the temperature of the cooling water W or the lubricating oil. That is, it is preferable that the driving voltage of the cooling fan 63 is reduced to reduce the air volume and the load of the cooling fan 63 as the temperature of at least one of the cooling water W and the lubricating oil decreases.

  Further, in the fuel supply device 3 for the internal combustion engine of the present embodiment described above, both the cooling water W and the high-pressure pump unit 55 are cooled by the cooling fan 63. However, the fuel supply device for an internal combustion engine according to the present invention is not limited to this, and only one of the cooling water W and the high-pressure pump unit 55 may be cooled.

  Further, in the fuel supply device 3 for the internal combustion engine of the present embodiment described above, the cooling fan 63 of the radiator 62 is used to air-cool the high-pressure pump unit 55. However, the fuel supply device for an internal combustion engine according to the present invention is not limited to this, and a dedicated fan for air-cooling the high-pressure pump unit 55 may be provided.

  In the fuel supply device 3 for the internal combustion engine of the present embodiment described above, the fuel supply device 3 is applied to a gasoline engine. However, the fuel supply device for an internal combustion engine according to the present invention is not limited to this and may be applied to a diesel engine.

  As described above, the fuel supply device for an internal combustion engine according to the present invention has an effect of extending the life of the cooling fan for cooling the high-pressure pump, and is useful for the fuel supply device for the internal combustion engine. is there.

1 engine (internal combustion engine)
5 Fuel supply device 6 Cooling device (cooling medium circulation means)
7 ECU (control means)
55 High Pressure Pump (High Pressure Pump)
61c Cooling water temperature sensor (cooling medium temperature detecting means)
62 Radiator 63 Cooling fan 512a Feed pump W Cooling water (cooling medium)

Claims (3)

A feed pump for sucking, pressurizing and discharging the fuel of the internal combustion engine;
A high-pressure pump that sucks, pressurizes and discharges fuel discharged from the feed pump;
A cooling medium circulating means for circulating a cooling medium capable of cooling the high-pressure pump;
Cooling medium temperature detecting means for detecting the temperature of the cooling medium;
An electric cooling fan capable of cooling at least one of the high-pressure pump and the cooling medium;
A control unit for controlling the amount of fuel supplied from the feed pump to the high-pressure pump and controlling the cooling fan;
The control means operates at least one of the high-pressure pump and the cooling medium by operating the cooling fan on the condition that supply of the fuel from the feed pump to the high-pressure pump is stopped during driving of the internal combustion engine. A fuel supply device for an internal combustion engine, wherein the air volume of the cooling fan is reduced as the temperature of the cooling medium detected by the cooling medium temperature detecting means decreases. The cooling medium circulation means is a cooling water circulation system for circulating cooling water to each part of the internal combustion engine,
The cooling medium is the cooling water;
2. The fuel supply device for an internal combustion engine according to claim 1, wherein the cooling medium temperature detecting means is a water temperature meter for measuring a temperature of the cooling water. The fuel supply device for an internal combustion engine according to claim 2, wherein the cooling fan is a radiator fan that air-cools a radiator that cools the cooling water.

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