JP2007071140A - Fuel supply system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To operate two high pressure fuel pumps of a V type engine in the same phase or approximately the same phase while suppressing pulsation. <P>SOLUTION: This fuel supply system 12 includes the first high pressure fuel pump 200 with its pump plunger operated by a first cam 210 attached to an intake camshaft and the second high pressure fuel pump 300 with its pump plunger operated by a second cam 310 attached to the intake camshaft. The first cam 210 and the second cam 310 are operated in the same phase, and also the cam profiles of these cams have approximately the same phase at a top dead center and a bottom dead center, however, these shapes in response to a discharge stroke are different from each other, and different discharge characteristics are developed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention injects fuel into an intake passage or an intake port in addition to an internal combustion engine having a fuel injection means (in-cylinder injector) for injecting fuel at a high pressure into the cylinder. In particular, the present invention relates to a fuel supply device for an internal combustion engine provided with a fuel injection means (intake passage injection injector), and in particular, a fuel pressure in a high-pressure fuel system that supplies fuel to an in-cylinder injector (hereinafter referred to as fuel pressure) The present invention relates to a fuel supply device for an internal combustion engine that prevents pulsation.

  In general, in an automobile engine, fuel is supplied from a fuel tank to an engine (internal combustion engine) via a fuel pump and a fuel pipe, and the fuel is injected into the engine via an injector.

  A direct injection engine having an in-cylinder injector for injecting fuel into a combustion chamber of a gasoline engine, an in-cylinder injector for injecting fuel into a combustion chamber of a gasoline engine, and an intake passage 2. Description of the Related Art An engine that includes an intake manifold injector for fuel injection and that injects fuel between an in-cylinder injector and an intake manifold injector is known in accordance with the engine speed and the load on the internal combustion engine. In a high-pressure fuel system including an in-cylinder injector, fuel whose fuel pressure has been increased by a high-pressure fuel pump is supplied to the in-cylinder injector via a delivery pipe, and the in-cylinder injector is connected to each cylinder of the internal combustion engine. High pressure fuel is injected into the combustion chamber.

  In order to generate such high-pressure fuel, a high-pressure fuel pump that drives a pump plunger by a cam provided on a drive shaft (drive shaft such as an intake cam shaft or an exhaust cam shaft) connected to a crankshaft of an internal combustion engine Is used. The high-pressure fuel pump includes a pump plunger that reciprocates in the cylinder by the rotation of the cam, and a pressurizing chamber that includes the cylinder and the pump plunger. The pressurizing chamber has a pump supply pipe communicating with a feed pump for delivering fuel from the fuel tank, a return pipe for returning leaked fuel from the pump plunger to the fuel tank, and fuel in the pressurizing chamber directed to the in-cylinder injector. High-pressure delivery pipes are connected to each other. The high-pressure fuel pump is provided with an electromagnetic spill valve that opens and closes between the pump supply pipe and the high-pressure delivery pipe and the pressurizing chamber.

  When the electromagnetic spill valve is open and the pump plunger moves in the direction of increasing the volume of the pressurizing chamber, that is, when the high-pressure fuel pump is in the suction stroke, fuel is supplied from the pump supply pipe into the pressurizing chamber. Inhaled. Also, when the pump plunger moves in the direction of decreasing the volume of the pressurizing chamber, that is, when the high-pressure fuel pump is in the discharge stroke, closing the electromagnetic spill valve will disconnect the pump supply pipe from the pressurizing chamber. Then, the fuel in the pressurized chamber is pumped to the in-cylinder injector via the high-pressure delivery pipe.

  In such a high-pressure fuel pump, the fuel is pumped toward the in-cylinder injector only during the closing period of the electromagnetic spill valve during the discharge stroke. The fuel pumping amount is adjusted (by adjusting the closing period of the electromagnetic spill valve). In other words, the fuel pumping amount increases by increasing the closing period by increasing the closing timing of the electromagnetic spill valve, and the fuel pumping amount by shortening the closing period by delaying the closing period of the electromagnetic spill valve. Less. When the fuel pumping amount increases, the fuel pressure in the high-pressure delivery pipe increases. When the fuel pumping amount decreases, the fuel pressure in the high-pressure delivery pipe decreases.

  In this way, the fuel delivered from the feed pump is pressurized by the high-pressure fuel pump, and the pressurized fuel is pumped toward the in-cylinder injector at an appropriate fuel pressure, so that the fuel is directly fed into the combustion chamber. Even in an internal combustion engine that supplies fuel, fuel injection can be performed accurately.

  In such a high-pressure fuel pump, since the discharge pressure of the high-pressure fuel pump pulsates because one plunger repeats the suction stroke and the discharge stroke, the pressure of the fuel in the high-pressure delivery pipe (fuel pressure) ) Varies according to the discharge pulsation of the high-pressure fuel pump. Therefore, the amount of fuel injected from the in-cylinder injector into the cylinder increases when the fuel pressure in the high-pressure delivery pipe is high, and decreases when the fuel pressure is low. As described above, when the injection amount of the fuel injected into the cylinder changes in accordance with the fluctuation of the fuel pressure, there arises a problem that the engine torque also fluctuates and the emission is deteriorated.

  In particular, in a multi-cylinder internal combustion engine such as a V-type 8-cylinder, a high-pressure fuel pump is provided in each of two high-pressure delivery pipes, one for each of the left and right banks. In a fuel injection device configured to supply fuel to each high pressure delivery pipe, for example, the discharge timings of two high pressure fuel pumps are shifted so that the discharge pulsations generated by the two high pressure fuel pumps cancel each other. By doing so, fluctuations in the fuel pressure can be reduced.

For example, FIG. 1 of JP-A-2002-213326 (Patent Document 1) discloses such a fuel supply device for an internal combustion engine. In the fuel supply device disclosed in this publication, the phases of the cams that drive the plungers of the two high-pressure fuel pumps are shifted by 90 °. For this reason, when one high-pressure fuel pump is in the discharge stroke, the other high-pressure fuel pump is in the intake stroke, so the magnitude of fuel pulsation (the absolute value of the difference between the highest pressure and the lowest pressure) is reduced. can do.
JP 2002-213326 A

  However, in order to ensure the reliability of the diaphragm of the pulsation damper provided in the low-pressure piping in front of such a high-pressure fuel system, the phases of the cams that drive the plungers of the two high-pressure fuel pumps are the same or the same. There are cases where it is required to make the phase close to the phase. This is because the amplitude of the diaphragm of the pulsation damper during idling is larger in the case of the opposite phase of the cam than in the case of the same phase.

  In such a case, if the cam phase is set to the same phase or a phase close to the same phase, the number of fuel injections from the injector corresponding to the discharge of one high-pressure fuel pump increases, and the magnitude of the pulsation is reversed. It becomes twice the magnitude of the pulsation when the phase is set. When the magnitude of the pulsation increases, there may occur a problem that the fuel injection amount fluctuates, the engine torque also fluctuates, and the emission deteriorates.

  Thus, reducing the magnitude of the pulsation and making the phase of the cam that drives the high-pressure fuel pump the same phase (or a phase close to the same phase) are contradictory events.

  Although it is conceivable to increase the volume of the high-pressure fuel system in order to reduce the magnitude of pulsation, it takes time to increase the pressure from when the fuel pressure is low. Needless to say, if the high-pressure fuel system is completely distinguished by the left and right banks, two fuel pressure sensors and the like are required, resulting in an increase in cost.

  The present invention has been made to solve the above-described problems, and an object thereof is to suppress pulsation of fuel pressure in an internal combustion engine using a plurality of (for example, two) high-pressure fuel pumps. It is an object of the present invention to provide a fuel supply device for an internal combustion engine capable of operating a high-pressure fuel pump in the same phase or substantially in the same phase.

  A fuel supply apparatus for an internal combustion engine according to a first aspect of the present invention is a fuel supply apparatus for an internal combustion engine that includes a plurality of high-pressure fuel pumps that supply high-pressure fuel from a fuel tank to fuel injection means. The plunger of the high-pressure fuel pump is operated by a cam driven by the internal combustion engine, and the desired discharge is performed by the plunger in the discharge stroke after the on-off valve on the inlet side of the high-pressure fuel pump is closed at a desired timing based on the cam angle. An amount of high pressure fuel is discharged. A different cam is provided for each high-pressure fuel pump. In these cams, the phase of the top dead center and the phase of the bottom dead center are substantially the same, and the shapes of the cams corresponding to the discharge stroke are different.

  According to the first invention, the shape (cam profile) of the cam that operates the plunger of the high-pressure fuel pump differs for each high-pressure fuel pump in the portion corresponding to the discharge stroke. For example, when two high-pressure fuel pumps are provided for each bank of the V-type internal combustion engine, the profiles corresponding to the discharge strokes of the cams of the two high-pressure fuel pumps are different. For this reason, even if the two high-pressure fuel pumps are the same, the discharge characteristics (change in discharge amount with time) can be made different. For this reason, the magnitude of the pulsation generated when the same cam is simply operated in the same phase can be further reduced by the different discharge characteristics. As a result, in an internal combustion engine using two high-pressure fuel pumps, a fuel supply device for an internal combustion engine capable of operating the high-pressure fuel pump in the same phase or substantially in the same phase while suppressing pulsation of fuel pressure. Can be provided.

  In the internal combustion engine fuel supply apparatus according to the second invention, in addition to the configuration of the first invention, these cams have the same cam shape corresponding to the intake stroke before the on-off valve is closed.

  According to the second aspect of the invention, the two high-pressure fuel pumps can be operated in the same way in the intake stroke and differently in the discharge stroke.

  In the fuel supply device for an internal combustion engine according to the third invention, in addition to the configuration of the first or second invention, the internal combustion engine is a V-type internal combustion engine, and a fuel pump is disposed in each bank. Is an institution.

  According to the third invention, the two high-pressure fuel pumps provided in each bank of the V-type internal combustion engine can be operated in the same way in the intake stroke and differently in the discharge stroke.

  A fuel supply device for an internal combustion engine according to a fourth aspect of the invention is a fuel supply device for an internal combustion engine that includes two high-pressure fuel pumps that supply high-pressure fuel from a fuel tank to fuel injection means. The plunger of the high-pressure fuel pump is operated by a cam driven by the internal combustion engine, and the desired discharge is performed by the plunger in the discharge stroke after the on-off valve on the inlet side of the high-pressure fuel pump is closed at a desired timing based on the cam angle. An amount of high pressure fuel is discharged. The internal combustion engine is a V-type internal combustion engine, and has a plurality of cylinders in each bank, and fuel injection means is provided for each cylinder. The discharge pipes from the two high-pressure fuel pumps are connected. The fuel supply device for an internal combustion engine includes two supply pipes that are branched from connected discharge pipes and that supply high-pressure fuel for each bank, and pressure regulating valves that are respectively provided in the branched supply pipes. And a detecting means for detecting the pressure of the high-pressure fuel provided in the connected discharge pipe.

  According to the fourth invention, the discharge pipes from the two high-pressure fuel pumps are once connected and then branched. After the branching, each supply pipe is provided with a pressure regulating valve (a check valve that opens when a preset pressure is reached). For this reason, since two pressure regulating valves are provided in each supply pipe, even if two high-pressure fuel pumps operate in the same phase or in opposite phase, depending on the fuel pressure in each supply pipe, Will be allocated. For this reason, pulsation can be reduced. Furthermore, the detection means is not provided in each supply pipe, but is provided in a connected discharge pipe. As a result, in an internal combustion engine using two high-pressure fuel pumps, a fuel supply device for an internal combustion engine capable of operating the high-pressure fuel pump in the same phase or substantially in the same phase while suppressing pulsation of fuel pressure. Can be provided.

  In the fuel supply device for an internal combustion engine according to the fifth invention, in addition to the configuration of the fourth invention, the pressure regulating valve opens when a preset pressure is reached.

  According to the fifth aspect of the present invention, the valve is set to open at an extremely low pressure, and if even a slight pulsation occurs, the check valve is opened, so that the pulsation can be reduced.

  In the internal combustion engine fuel supply apparatus according to the sixth aspect of the invention, in addition to the structure of any one of the first to fifth aspects, the fuel injection means is a fuel injection means for injecting high-pressure fuel into the cylinder. .

  According to the sixth invention, in a gasoline engine that directly injects high-pressure fuel into a cylinder, the high-pressure fuel pump can be operated in the same phase and with reduced pulsation.

  In the fuel supply device for an internal combustion engine according to the seventh invention, in addition to the configuration of any one of the first to fifth inventions, the fuel injection means is a first fuel injection for injecting high-pressure fuel into the cylinder. The internal combustion engine further includes a feed pump and a second fuel injection means for injecting fuel at a feed pressure into the intake passage.

  According to the seventh aspect of the invention, in the gasoline engine that injects high pressure fuel directly into the cylinder and injects fuel into the intake passage, the high pressure fuel pump can be operated in the same phase and with pulsation suppressed. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
FIG. 1 shows an engine fuel supply system 10 according to an embodiment of the present invention. This engine is a V-type 8-cylinder gasoline engine, and includes an in-cylinder injector 110 that injects fuel into the cylinder of each cylinder, and an intake passage injector 120 that injects fuel into the intake passage of each cylinder. Have It should be noted that the present invention is not limited to such an engine, and is not limited to such an engine, but is a gasoline engine of another type that has at least an in-cylinder injector 110 (an engine shown in FIG. 2 described later) A common rail diesel engine may be used. Furthermore, the number of high-pressure fuel pumps is not limited to two. Further, the type of engine is not limited to the V-type 8-cylinder, but may be a type of V-type 6-cylinder, in-line 4-cylinder, in-line 6-cylinder, or the like. Furthermore, the shape of the cam that drives the high-pressure fuel pump is not limited to the following two shapes (changes depending on the number of cylinders).

  As shown in FIG. 1, the fuel supply system 10 is provided in a fuel tank, and is driven by a feed pump 100 that supplies fuel at a low pressure (pressure regulator pressure of about 400 kPa) and a first cam 210. The high-pressure fuel is supplied to the second high-pressure fuel pump 300 driven by the second cam 310 and the in-cylinder injector 110 that are different in discharge phase from the first high-pressure fuel pump 200 and the first cam 210. High pressure delivery pipe 112 provided for each of the left and right banks, four in-cylinder injectors 110 for each of the left and right banks provided in the high pressure delivery pipe 112, and an intake passage injection injector 120. A low pressure delivery pipe 122 provided for each of the left and right banks for supplying fuel, and the low pressure delivery pipe 12 And a left and right banks intake manifold injectors 120 for each of the four provided. For example, it is assumed that the first high-pressure fuel pump 200 is provided in the left bank and the second high-pressure fuel pump 300 is provided in the right bank.

  The discharge port of the fuel tank feed pump 100 is connected to a low-pressure supply pipe 400, and the low-pressure supply pipe 400 branches into a first low-pressure delivery communication pipe 410 and a pump supply pipe 420. The first low-pressure delivery communication pipe 410 becomes a second low-pressure delivery communication pipe 430 on the downstream side of the branch point with the low-pressure delivery pipe 122 of one bank of the V-shaped bank, and the low-pressure delivery pipe 122 of the other bank. It is connected to the.

  The pump supply pipe 420 is connected to the inlets of the first high-pressure fuel pump 200 and the second high-pressure fuel pump 300, respectively. A first pulsation damper 220 is provided in front of the entrance of the first high-pressure fuel pump 200, and a second pulsation damper 320 is provided in front of the entrance of the second high-pressure fuel pump 300, respectively. The fuel pulsation is reduced.

  The discharge port of the first high-pressure fuel pump 200 is connected to the first high-pressure delivery communication pipe 500, and the first high-pressure delivery communication pipe 500 is connected to the high-pressure delivery pipe 112 of one bank of the V-shaped bank. . The discharge port of the second high-pressure fuel pump 300 is connected to the second high-pressure delivery communication pipe 510, and the second high-pressure delivery communication pipe 510 is connected to the high-pressure delivery pipe 112 of the other bank of the V-shaped bank. The The high-pressure delivery pipe 112 of one bank of the V-type bank and the high-pressure delivery pipe 112 of the other bank are connected by a high-pressure communication pipe 520.

  The electromagnetic relief valve 114 provided in the high pressure delivery pipe 112 is connected to the high pressure fuel pump return pipe 600 via the high pressure delivery return pipe 610. Return ports of the high-pressure fuel pump 200 and the high-pressure fuel pump 300 are connected to a high-pressure fuel pump return pipe 600. The high-pressure fuel pump return pipe 600 is connected to the return pipe 620 and the return pipe 630, and is connected to the fuel tank.

  FIG. 2 shows another engine fuel supply system 12 according to an embodiment of the present invention. The fuel supply system 12 shown in FIG. 2 has the in-cylinder injector 110 of the engine fuel supply system 10 shown in FIG. 1, and does not have the intake passage injector 120. In the engine fuel supply system 12 shown in FIG. 2, the same reference numerals and names are used for the components having the same functions as those of the engine fuel supply system 10 shown in FIG. Therefore, detailed description thereof will not be repeated here. In the engine shown in FIG. 2, as in the engine shown in FIG. 1, the engine type is not limited to the V-type 8-cylinder, but may be a V-type 6-cylinder, in-line 4-cylinder, in-line 6-cylinder, etc. . Furthermore, the shape of the cam that drives the high-pressure fuel pump is not limited to the following two shapes (changes depending on the number of cylinders).

  FIG. 3 shows an enlarged view of the vicinity of the first high-pressure fuel pump 200 of FIGS. 1 and 2. The second high-pressure fuel pump 300 has a similar configuration. What is characteristic is that the cam phase is the same phase (or almost the same phase), but the cam profile corresponding to the discharge stroke is made different to shift the fuel discharge timing to suppress the occurrence of pulsation. It is. Further, it is assumed that the characteristics of the first high-pressure fuel pump 200 and the second high-pressure fuel pump 300 are the same. In the description using FIG. 3, the high-pressure fuel pump 200 will be described, and the components of the high-pressure fuel pump 300 will be shown in parentheses.

  The high pressure fuel pump 200 (high pressure fuel pump 300) includes a pump plunger 206 (pump plunger 306) that is driven by a first cam 210 (second cam 310) and slides up and down, and an electromagnetic spill valve 202 (electromagnetic). The spill valve 302) and the check valve 204 (check valve 304) are main components.

  When the pump plunger 206 (pump plunger 306) is moved downward by the first cam 210 (second cam 310) and the electromagnetic spill valve 202 (electromagnetic spill valve 302) is open. When the pump plunger 206 (pump plunger 306) is moved upward by the first cam 210 (second cam 310), the electromagnetic spill valve 202 (electromagnetic spill valve 202) The timing for closing the valve 302) is changed to control the amount of fuel discharged from the high-pressure fuel pump 200 (high-pressure fuel pump 300). During the discharge stroke in which the pump plunger 206 (pump plunger 306) is moving upward, more fuel is discharged as the timing for closing the electromagnetic spill valve 202 (electromagnetic spill valve 302) is earlier, and less as the fuel is slower. Discharged. The drive duty of the electromagnetic spill valve 202 (electromagnetic spill valve 302) when discharging the most is 100%, and the drive duty of the electromagnetic spill valve 202 (electromagnetic spill valve 302) when discharging the least is 0%. It is said. When the drive duty of the electromagnetic spill valve 202 (electromagnetic spill valve 302) is 0%, the electromagnetic spill valve 202 (electromagnetic spill valve 302) remains open without being closed, and the first cam 210 (first As long as the second cam 310 is rotating (as long as the engine is rotating), the pump plunger 206 (pump plunger 306) slides up and down, but the electromagnetic spill valve 202 (electromagnetic spill valve 302) Since it does not close, the fuel is not pressurized.

  The pressurized fuel pushes open the check valve 204 (check valve 304) (set pressure of about 60 kPa), and the high-pressure delivery pipe 112 through the first high-pressure delivery communication pipe 500 (second high-pressure delivery communication pipe 510). To be pumped. At this time, the high-pressure fuel pumps 200 and 300 are feedback-controlled using the fuel pressures detected by the fuel pressure sensors provided in the high-pressure delivery pipes 112 of the left and right banks, respectively. Further, as described above, the high pressure delivery pipe 112 of one bank of the V type and the high pressure delivery pipe 112 of the other bank are communicated by the high pressure communication pipe 520.

  The first cam 210 and the second cam 310 are provided on the camshaft (intake camshaft or exhaust camshaft) of each bank so as to have the same phase (including substantially the same phase). ing. As described above, the fuel supply system according to the present embodiment is characterized in that the first cam 210 and the second cam 310 have the same phase and the pulsation of the fuel pressure is reduced. The cam profiles of the cam 210 and the second cam 310 are set.

  FIG. 4 shows an enlarged view of the first cam 210, and FIG. 5 shows an enlarged view of the second cam 310, respectively. As shown in FIGS. 4 and 5, these two cams 210 and 310 have the same cam profile corresponding to the suction stroke, but have different cam profiles corresponding to the discharge stroke. 4 and 5 show the rotation direction of the cam, the stroke name corresponding to the rotation angle of the cam (either the suction stroke or the discharge stroke), TDC (Top Dead Center) and BDC (Bottom Dead Center). Show. A cam profile indicated by a dotted line in the discharge stroke in FIGS. 4 and 5 is a cam profile in the suction stroke, and is a normal (for example, conventional cam) cam profile.

  The cam profile of the first cam 210 shown in FIG. 4 is as follows when compared with the cam profile of the second cam 310 shown in FIG.

  The cam profile of the first cam 210 is set so that the pump plunger 206 reaches the vicinity of the maximum lift amount earlier than the second cam 310 in the discharge stroke from BDC to TDC. The cam profile of the first cam 210 is such that the lift amount of the pump plunger 206 is larger than the lift amount of the pump plunger 306 by the second cam 310 in the early phase (on the BDC side) in the discharge stroke. Is set. The opposite is true for the cam profile of the second cam 310. The first cam 210 and the second cam 310 have a cam profile represented by such characteristics.

  The cam profiles in FIGS. 4 and 5 are merely examples, and it is only necessary to develop the above-described characteristics. The present invention is not limited to the shape of the cam profiles themselves in FIGS. 4 and 5. Absent.

The operation of the engine fuel supply system having the above structure will be described.
When the engine is started, the crankshaft is rotated, and the camshaft (two intake camshafts and two exhaust camshafts on the left and right banks) connected to the crankshaft by a timing belt or the like is rotated. For example, a first cam 210 provided between the # 3 and # 4 cylinders of the intake camshaft of the left bank (first high pressure fuel pump 200 side), and the right bank (second high pressure fuel). The second cam 310 provided between the # 7 cylinder and the # 8 cylinder of the intake camshaft of the pump 300 side) rotates. Since the cam profiles of the first cam 210 and the second cam 310 have shapes as shown in FIGS. 4 and 5, different discharge characteristics (discharge amount) are developed in the discharge stroke.

  FIG. 6 shows the relationship between the cam rotation angle (discharge stroke) and the lift amount (discharge amount) in the first high-pressure fuel pump 200 driven by the first cam 210, and FIG. The relationship between the cam rotation angle (discharge stroke) and the lift amount (discharge amount) in the second high-pressure fuel pump 300 driven by 310 is shown. As shown in FIGS. 6 and 7, the discharge characteristics can be made different between the first high-pressure fuel pump 200 in the left bank and the second high-pressure fuel pump 300 in the right bank. For this reason, as shown in FIG. 8, the magnitude of the pulsation can be reduced in the present invention as compared with the conventional case where the same cam is simply used in the same phase (dotted line in FIG. 8) (FIG. 8). Solid line). This is because, when a certain discharge amount is necessary, the pressure increase timing of the fuel pressure by the high pressure fuel pumps in the left and right banks changes, and the pulsation is reduced by overlapping with the fuel injection from the injector.

  As described above, according to the fuel supply apparatus for an engine according to the present embodiment, the profiles in the discharge strokes of the cams that drive the high-pressure fuel pumps provided in the left and right banks are made different. For this reason, the discharge performances of the left and right high-pressure fuel pumps are different, and even if they are operated in the same phase, they do not have the same discharge characteristics, so the pulsation of fuel pressure can be reduced. As a result, the left and right high-pressure fuel pumps are operated in the same phase, so that the problem of operating the left and right high-pressure fuel pumps in the opposite phase can be solved, and the pulsation of the fuel pressure can be reduced, and the fuel resulting from the pulsation Problems such as variations in the injection amount can be avoided.

<Second Embodiment>
Hereinafter, an engine fuel supply system according to a second embodiment of the present invention will be described. The engine fuel supply system 13 according to the present embodiment has the same basic configuration as the engine fuel supply system 12 (FIG. 2) according to the first embodiment described above, and a part of the configuration. Is different. The differences will be described below, and detailed description of the same configuration will not be repeated here.

  FIG. 9 shows an engine fuel supply system 13 according to an embodiment of the present invention. This fuel supply system 13 corresponds to the fuel supply system 12 of FIG. Note that this embodiment may also be applied to an engine having the intake manifold injector 120 in addition to the in-cylinder injector 110, as in the first embodiment.

The fuel supply system 12 shown in FIG. 2 is different from the fuel supply system 13 shown in FIG. 9 in the following points.
1) The high pressure communication pipe 520 is provided in the fuel supply system 12 but is not provided in the fuel supply system 13 (that is, the high pressure delivery pipe 112 is separated by the left and right banks),
2) The first high-pressure delivery communication pipe 500 and the second high-pressure delivery communication pipe 510 are connected before connection to the high-pressure delivery pipe 112.
3) After the connection between the first high-pressure delivery communication pipe 500 and the second high-pressure delivery communication pipe 510, the high pressure in the left bank via the first high-pressure delivery communication pipe 501 connected via the check valve 501B. Point connected to delivery pipe 112,
4) After the connection between the first high-pressure delivery communication pipe 500 and the second high-pressure delivery communication pipe 510, the high-pressure in the right bank via the second high-pressure delivery communication pipe 511 connected via the check valve 511B. Point connected to delivery pipe 112,
5) The fuel pressure sensor 521 is provided after the connection.

  The valve opening pressures of the check valve 501B and the check valve 511B are extremely low pressures. Even if the high-pressure fuel pump 200 and the high-pressure fuel pump 300 are operated in the same phase by the check valve 501B and the check valve 511B, they are distributed according to the fuel pressure in each high-pressure delivery pipe 112. . For this reason, pulsation can be reduced.

  In addition, since the fuel pressure sensor 521 is provided after the first high-pressure delivery communication pipe 500 and the second high-pressure delivery communication pipe 510 are connected, The number of fuel pressure sensors can be smaller than when one is provided.

  In FIG. 9, the relief valve 114 is provided in each of the high-pressure delivery pipes 112 of the left and right banks, but the present invention may be provided in the high-pressure delivery pipe 112 of any one of the banks. By doing so, the number of relief valves can be reduced.

  With this configuration, pulsation can be suppressed regardless of whether the two high-pressure fuel pumps have the same phase or the opposite phase or one high-pressure fuel pump.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall schematic diagram (part 1) of a fuel supply system for a gasoline engine according to a first embodiment of the present invention. It is a whole schematic diagram (the 2) of a fuel supply system of a gasoline engine concerning a 1st embodiment of the present invention. It is the elements on larger scale of FIG. 1 and FIG. FIG. 4 is an enlarged view of the first cam in FIG. 3. FIG. 4 is an enlarged view of the second cam in FIG. 3. It is a figure which shows the relationship between the rotation angle of a 1st cam, and lift amount. It is a figure which shows the relationship between the rotation angle of a 2nd cam, and lift amount. It is a figure which shows the change of the pressure of the high pressure fuel in the fuel supply system of the gasoline engine based on 1st Embodiment. FIG. 3 is an overall schematic diagram of a fuel supply system for a gasoline engine according to a second embodiment of the present invention.

Explanation of symbols

  10, 12, 13 Fuel supply system, 100 Feed pump, 110 In-cylinder injector, 112 High pressure delivery pipe, 114 Electromagnetic relief valve, 120 Intake passage injection injector, 122 Low pressure delivery pipe, 200 First high pressure fuel pump, 202 electromagnetic spill valve, 204 check valve, 206 pump plunger, 210 first cam, 220 first pulsation damper, 300 second high pressure fuel pump, 310 second cam, 320 second pulsation damper, 400 low-pressure supply pipe, 410 first low-pressure delivery communication pipe, 420 pump supply pipe, 430 second low-pressure delivery communication pipe, 500 first high-pressure delivery communication pipe, 510 second high-pressure delivery communication pipe, 520 high-pressure communication pipe Type, 600 high pressure fuel pump return pipe, 610 high pressure delivery return pipe, 620,630 return pipe.

Claims (7)

A fuel supply device for an internal combustion engine including a plurality of high pressure fuel pumps for supplying high pressure fuel from a fuel tank to fuel injection means, wherein a plunger of the high pressure fuel pump is operated by a cam driven by the internal combustion engine, and the cam In the discharge stroke after closing the on-off valve on the inlet side of the high-pressure fuel pump at a desired timing based on the angle of the high-pressure fuel of a desired discharge amount is discharged by the plunger,
A different cam is provided for each high-pressure fuel pump,
The top dead center and bottom dead center phases are almost the same,
A fuel supply device for an internal combustion engine, wherein the shape of the cam corresponding to the discharge stroke is different.   2. The fuel supply device for an internal combustion engine according to claim 1, wherein the cam has the same shape corresponding to an intake stroke before the on-off valve is closed. The internal combustion engine
A V-type internal combustion engine,
The fuel supply device for an internal combustion engine according to claim 1, wherein the fuel pump is disposed in each bank. A fuel supply device for an internal combustion engine including two high-pressure fuel pumps for supplying high-pressure fuel from a fuel tank to fuel injection means, wherein a plunger of the high-pressure fuel pump is operated by a cam driven by the internal combustion engine, In the discharge stroke after closing the on-off valve on the inlet side of the high-pressure fuel pump at a desired timing based on the cam angle, the plunger discharges a high-pressure fuel of a desired discharge amount,
The internal combustion engine is a V-type internal combustion engine having a plurality of cylinders in each bank, provided with fuel injection means for each cylinder, connected to discharge pipes from two high-pressure fuel pumps,
Two supply pipes branched from the connected discharge pipes for supplying high-pressure fuel to each bank;
A pressure regulating valve provided in each of the supply pipes after being branched;
A fuel supply device for an internal combustion engine, comprising: detection means for detecting the pressure of the high-pressure fuel provided in the connected discharge pipe.   The fuel supply device for an internal combustion engine according to claim 4, wherein the pressure regulating valve opens when a preset pressure is reached.   The fuel supply device for an internal combustion engine according to any one of claims 1 to 5, wherein the fuel injection means is fuel injection means for injecting high-pressure fuel into a cylinder. The fuel injection means is a first fuel injection means for injecting high-pressure fuel into a cylinder,
The fuel supply device for an internal combustion engine according to any one of claims 1 to 5, wherein the internal combustion engine further includes a feed pump and a second fuel injection means for injecting fuel at a feed pressure into the intake passage. .

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