JP2005351135A - Fuel supply device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply device of an internal combustion engine capable of restraining generation of noise. <P>SOLUTION: First and second high pressure fuel pumps 30a and 30b further pressurize fuel supplied from a feed pump 11. The first high pressure fuel pump 30a is formed of a quantity adjustable high pressure fuel pump capable of adjusting a delivery quantity, and the second high pressure fuel pump 30b is formed of a quantity nonadjustable high pressure fuel pump. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel supply device for an internal combustion engine that includes a plurality of high-pressure fuel pumps that further pressurize fuel supplied from a feed pump.

Conventionally, as this type of device, for example, the one shown in Patent Document 1 is known.
In other words, this apparatus includes a metering type high-pressure fuel pump having an electromagnetic valve for overflowing fuel sucked into a pressurizing chamber defined by a cylinder and a plunger that reciprocates in the cylinder. Configured. In this metering type high pressure fuel pump, a fixed amount of fuel corresponding to the lift amount of the plunger is sucked into the pressurizing chamber in the suction stroke. On the other hand, in the pressurizing stroke, the amount of fuel overflowing from the pressurizing chamber is adjusted through the opening / closing control of the solenoid valve according to the required fuel amount of the internal combustion engine, thereby reducing the fuel discharge amount. It is metered.

Further, in this device, for example, in correspondence with an internal combustion engine having a large amount of required fuel such as a direct injection internal combustion engine composed of V type 8 cylinders, one such metering type high pressure fuel pump is provided for each bank, That is, it is set as the structure provided with two in total. However, in this case, as the number of pumps increases, the noise associated with the opening / closing operation of the electromagnetic valve increases as a whole. Therefore, in this apparatus, when the required fuel amount of the internal combustion engine is small, such as when idling, the fuel is pressurized and pressure-fed using only one of the two pumps, thereby noise caused by the opening / closing operation of the electromagnetic valve. We try to reduce it as a whole.
JP 2002-213326 A

  However, in the above device, even when the amount of required fuel is small, the noise accompanying the opening / closing operation of the solenoid valve can be reduced as a whole, but both when the required fuel amount is large, such as when the vehicle on which the internal combustion engine is mounted is running. The metering type high-pressure fuel pump is operated, and the opening / closing operation of the solenoid valve, in other words, the noise accompanying the metering operation of the discharge amount increases as the whole apparatus.

  The metering type high-pressure fuel pump is not limited to the metering of the discharge amount using the electromagnetic valve as described above. For example, the profile of the cam for reciprocating the plunger is set with respect to the axis of the camshaft. It is conceivable to adjust the stroke of the plunger and thus the discharge amount by controlling the amount of movement of the shaft in the axial direction. However, in any case, both metering type high pressure fuel pumps are operated when the required fuel amount is large, and the problem that the noise accompanying the metering operation increases as a whole still remains as described above. .

  The present invention has been made in view of such circumstances, and an object thereof is to provide a fuel supply device for an internal combustion engine that can suppress the generation of noise.

In the following, means for achieving the above object and its effects are described.
First, the invention according to claim 1 is a fuel supply apparatus for an internal combustion engine comprising a plurality of high-pressure fuel pumps that further pressurize fuel supplied from a feed pump, and discharges some of the plurality of high-pressure fuel pumps. The gist is that the metering type high-pressure fuel pump is capable of metering, and the other pumps are non-metering type high-pressure fuel pumps.

  According to this configuration, unlike the configuration in which all of the plurality of high-pressure fuel pumps are metering-type high-pressure fuel pumps, it is possible to suppress the generation of noise associated with the discharge amount metering operation as a whole apparatus.

The gist of the invention according to claim 2 is that, in the invention according to claim 1, the metering type high-pressure fuel pump regulates the discharge amount through open / close control of the electromagnetic valve.
According to this configuration, it is possible to suppress noise generated with the opening / closing operation of the solenoid valve as a whole.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the discharge amount of the non-metering type high pressure fuel pump is set to be smaller than the maximum discharge amount of the metering type high pressure fuel pump. Is the gist.

  According to the same configuration, for example, the maximum discharge amount of the entire apparatus is the same as that of the configuration in which the discharge amount of the non-metering type high pressure fuel pump is set larger than the maximum discharge amount of the metering type high pressure fuel pump. In this case, a wide adjustment range of the discharge amount can be secured.

  According to a fourth aspect of the present invention, in the third aspect of the invention, the discharge amount of the non-metering type high-pressure fuel pump is made smaller than the minimum discharge amount in the metering range of the discharge amount of the metering type high-pressure fuel pump. The gist is that it is set to a small amount.

  For example, in a configuration in which all high-pressure fuel pumps are metering-type high-pressure fuel pumps, all the high-pressure fuel pumps are stopped and set to “0” with respect to the discharge amount of the entire apparatus, or high-pressure fuel pumps are used. Even if only one pump is operated and this can be set to the lower limit side metering limit of the pump, that is, the above-mentioned minimum discharge amount, it cannot be made smaller than this minimum discharge amount.

  In that respect, according to the present invention, the operation of the metering type high-pressure fuel pump is stopped, and the fuel discharge is performed only by the non-metering type high-pressure fuel pump. The amount can be made smaller than the amount. Therefore, when the required fuel amount of the internal combustion engine is smaller than the minimum discharge amount, the discharge amount of the entire apparatus can be made closer to the required fuel amount, and finer adjustment of the discharge amount is possible. It becomes.

  The “minimum discharge amount” in the present invention refers to the discharge amount adjustment range when the metering type high-pressure fuel pump is in operation, and the discharge amount when the pump is stopped (ie, “0”). Different from

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, when the required fuel amount in the internal combustion engine is equal to or less than a discharge amount of the non-metering type high-pressure fuel pump, The gist is that the operation of the metering type high-pressure fuel pump is stopped and fuel is discharged only by the non-metering type high-pressure fuel pump.

According to this configuration, when the required fuel amount in the internal combustion engine is equal to or less than the discharge amount of the non-metering fuel pump, it is possible to completely prevent the generation of noise associated with the metering operation.
According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the amount of discharge of the non-metering type high pressure fuel pump is a required fuel when the internal combustion engine is in an idle operation state. The gist is that the amount is set.

  If the required fuel amount when the internal combustion engine is in the idle operation state is controlled through the metering operation of the discharge amount of the metering type high-pressure fuel pump, generation of noise due to the metering operation cannot be avoided. On the other hand, when the required fuel amount during idle operation is secured by fuel discharge by the non-metering type high-pressure fuel pump, noise generation due to such metering operation can be suppressed, but the non-metering type high-pressure fuel pump If the discharge amount exceeds the required fuel amount during idle operation, energy loss associated with the driving of the non-metering type high-pressure fuel pump will occur accordingly.

  In that respect, according to the present invention, when the internal combustion engine is in the idling operation state, the operation of the metering type high-pressure fuel pump is stopped so that the minimum discharge amount as the entire apparatus is equal to the required fuel amount during the idling operation. Therefore, useless fuel discharge exceeding the required fuel amount during idle operation can be avoided as much as possible. As a result, wasteful energy consumption can be suppressed and fuel consumption can be improved.

  In addition, during idling, the combustion noise of the internal combustion engine is reduced, and other noises are relatively easily recognized by the driver. In that respect, according to the present invention, since noise generated in the discharge amount adjustment operation can be eliminated in a state where noise can be recognized relatively easily, the noise prevention effect becomes even more remarkable.

  A seventh aspect of the present invention is the metering high-pressure fuel pump according to any one of the first to sixth aspects, wherein the metering type high-pressure fuel pump includes an amount of fuel overflowing from the pressurizing chamber and the pressurizing chamber. The discharge amount is adjusted through adjustment of at least one of the amounts of fuel to be sucked, and the fuel from the feed pump is supplied to the high-pressure fuel pumps via a plurality of branch paths connected to the high-pressure fuel pumps. The length of the branch path from the branch point of the branch path to the metering type high pressure fuel pump is larger than the length of the branch path from the branch point to the non-metering type high pressure fuel pump. The gist is that it is set for a long time.

  In a metering type high-pressure fuel pump that regulates the discharge amount through the metering of at least one of the amount of fuel overflowing from the pressurizing chamber and the amount of fuel sucked into the pressurizing chamber, it propagates to the feed pump side. Pressure pulsation is likely to occur in the branch path with the discharge amount adjustment operation. When such a pressure pulsation reaches a branch point, there is a concern that fuel intake of the non-metering type high-pressure fuel pump, and thus pump efficiency, may be adversely affected.

  In this regard, in the present invention, regarding the length of the branch path from the branch point, the length to the metering type high-pressure fuel pump is set longer than the length to the non-metering type high-pressure fuel pump. The pressure pulsation from the high pressure fuel pump is preferably damped by the time the branch point is reached. Accordingly, it is possible to suppress a decrease in pump efficiency in the non-metering type high-pressure fuel pump.

Hereinafter, an embodiment in which the present invention is embodied as a fuel supply device applied to an in-cylinder direct injection internal combustion engine will be described with reference to FIGS. 1 and 2.
The cylinder arrangement of the internal combustion engine to which the present invention is applied is a V-type 8-cylinder arrangement in which each of the first and second banks has four cylinders. In the following description, among components having the same number as the reference numeral, it is necessary to distinguish each bank. Components are distinguished by adding “b” at the end. In particular, for those that do not need to be distinguished from each other, only numbers are assigned as symbols.

  As shown in FIG. 1, the fuel supply device for an internal combustion engine includes a feed pump 11 and first and second high-pressure fuel pumps 30a and 30b. The feed pump 11 pumps up fuel stored in the fuel tank 10, and the high-pressure fuel pumps 30a and 30b further pressurize and pump out the pumped fuel. The high-pressure fuel delivered from the high-pressure fuel pumps 30a and 30b is pressure-fed to the corresponding high-pressure fuel pipes (delivery pipes) 17a and 17b. The high-pressure fuel sent to the high-pressure fuel pipes 17a and 17b is stored in a state where it is maintained at a necessary pressure, and is distributed to the injectors 22 provided for each cylinder of the internal combustion engine. The injector 22 injects and supplies the required amount of fuel to the internal combustion engine at the required timing.

  In this internal combustion engine, one bank is provided with one high-pressure fuel pipe 17a, 17b, and four injectors 22 for one bank are connected to each high-pressure fuel pipe 17a, 17b. Has been. One high-pressure fuel pump 30a, 30b is provided for each corresponding high-pressure fuel pipe 17a, 17b. Incidentally, in the internal combustion engine, the two high-pressure fuel pipes 17a and 17b are connected through the connection pipe 18, and substantially function as an integrated high-pressure fuel pipe.

  The fuel pumped up by the feed pump 11 in the fuel supply apparatus is sent to the high-pressure fuel pumps 30a and 30b through the fuel supply path 12. The fuel supply path 12 is for supplying the fuel in the fuel tank 10 to the high-pressure fuel pipes 17a and 17b. The branch point 13 and the high-pressure fuel pipes 17a and 17b set in the middle of the fuel supply path 12 are separately provided. It has branching paths 14a and 14b to be connected. The high-pressure fuel pumps 30a and 30b are provided in the middle of the corresponding branch paths 14a and 14b, respectively. Each high-pressure fuel pump 30a, 30b is capable of pumping pressurized high-pressure fuel to each high-pressure fuel pipe 17a, 17b through the corresponding branch path 14a, 14b. A check valve 19 is provided in the middle of each branch passage 14a, 14b where the high-pressure fuel is pumped, and the fuel flows backward from the high-pressure fuel pipes 17a, 17b to the high-pressure fuel pumps 30a, 30b. Is to be prevented.

  A drain passage 21 is connected to a high-pressure fuel pipe 17 b that is one high-pressure fuel pipe via a relief valve 20. The relief valve 20 is opened when the fuel pressure in the high-pressure fuel pipe 17b and thus in the high-pressure fuel pipe 17a exceeds a predetermined pressure (for example, 14 to 14.5 MPa), and a part of the fuel stored in the pipe is removed. It returns to the fuel tank 10 through the drain passage 21. This prevents an excessive increase in fuel pressure in the high-pressure fuel pipes 17a and 17b.

  Each high-pressure fuel pump 30a, 30b includes a cylinder 32 and a plunger 33 therein. The plunger 33 is disposed so as to reciprocate within the cylinder 32. On the camshaft 23 for the intake valve or exhaust valve of the internal combustion engine, pump cams 24a and 24b are provided corresponding to the high-pressure fuel pumps 30a and 30b, respectively. Each corresponding plunger 33 is reciprocated with a constant stroke by the rotation of 24b.

  Inside each of the high-pressure fuel pumps 30a and 30b, a pressurizing chamber 34 is defined by a cylinder 32 and a plunger 33. Each pressurizing chamber 34 is connected to the branch point 13 via valve chambers 31a and 31b formed in the corresponding high-pressure fuel pumps 30a and 30b and a part of each branch passage 14a and 14b. Each check valve 19 is connected to the high-pressure fuel pipes 17a and 17b via the other branches 14a and 14b.

  The volume of the pressurizing chamber 34 changes according to the reciprocation of the plunger 33. In the suction stroke of each high-pressure fuel pump 30a, 30b in which the volume of the pressurizing chamber 34 is expanded by this reciprocating motion, the fuel enters the pressurizing chamber 34 from the branch point 13 side via the respective branch paths 14a, 14b. Inhaled. Further, in the pressurization stroke of each high-pressure fuel pump 30a, 30b in which the volume of the pressurization chamber 34 is reduced, the fuel sucked into the pressurization chamber 34 in the suction stroke is supplied via the check valve 19 to the high-pressure fuel pipe 17a. 17b can be discharged. In each pressurizing chamber 34, since the plunger 33 reciprocates with a constant stroke, the volume change amount (difference between the maximum volume and the minimum volume) accompanying the reciprocation is constant.

  In this embodiment, the cam crests are set at different heights between the pump cams 24a and 24b, and the stroke of the plunger 33 is different between the high-pressure fuel pumps 30a and 30b. That is, in the present embodiment, with such a configuration, the volume change amount of the pressurizing chamber 34 is set to be different between the first high pressure fuel pump 30a and the second high pressure fuel pump 30b. Specifically, the volume change amount in the first high-pressure fuel pump 30a is set larger than that in the second high-pressure fuel pump 30b.

Hereinafter, a characteristic configuration of the present embodiment will be described.
In the present fuel supply apparatus, of the two high-pressure fuel pumps, that is, the first and second high-pressure fuel pumps 30a and 30b, the first high-pressure fuel pump 30a adjusts the discharge amount to the high-pressure fuel pipe 17a side. While the control means for measuring is provided, the second high-pressure fuel pump 30b is configured not to have such control means.

  That is, an electromagnetic spill valve 35 is provided inside the first high-pressure fuel pump 30a. The electromagnetic spill valve 35 is an electromagnetic valve that opens and closes by energization control of the electromagnetic solenoid, thereby blocking communication between the valve chamber 31 a and the pressurizing chamber 34. Here, the electromagnetic spill valve 35 opens in response to the energization stop of the electromagnetic solenoid to connect the valve chamber 31a and the pressurizing chamber 34, and closes in response to the energization of the electromagnetic solenoid. It is configured to block communication.

  Therefore, if the electromagnetic spill valve 35 is opened during the intake stroke, the fuel from the fuel tank 10 side is drawn into the pressurizing chamber 34 through the valve chamber 31a. Here, when the pressurization stroke is reached with the electromagnetic spill valve 35 being opened, the fuel sucked into the pressurization chamber 34 in the suction stroke overflows into the valve chamber 31a. At this time, the fuel is returned from the valve chamber 31a to the fuel tank 10 via the fuel supply path 12 without being pumped to the high-pressure fuel pipe 17a. Therefore, if the electromagnetic spill valve 35 is kept open from the start to the end of the pressurization stroke, the fuel is not pumped to the high pressure fuel pipe 17a, that is, the first high pressure fuel pump 30a is operated. Can be stopped.

  On the other hand, when the electromagnetic spill valve 35 is closed during the pressurization stroke to shut off the valve chamber 31a and the pressurization chamber 34, the pressurization chamber 34 is reduced according to the volume reduction of the pressurization chamber 34 by the plunger 33. The fuel inside is increased in pressure. When the fuel pressure in the pressurizing chamber 34 becomes equal to or higher than a predetermined pressure, the check valve 19 is pushed open, and the fuel is pumped to the high pressure fuel pipe 17a.

  As described above, in the first high-pressure fuel pump 30a, the electromagnetic spill valve 35 is closed during the pressurization stroke so that the fuel is pressurized and discharged to the high-pressure fuel pipe 17a. In the first high-pressure fuel pump 30a, the amount of fuel discharged to the high-pressure fuel pipe 17a is adjusted by controlling the closing timing of the electromagnetic spill valve 35 during the pressurization stroke. That is, in the first high-pressure fuel pump 30a, fuel is discharged from the pressurizing chamber 34 to the high-pressure fuel pipe 17a only during the period in which the electromagnetic spill valve 35 in the pressurization stroke is closed. . Therefore, for example, if the valve closing period during the pressurization stroke is lengthened by, for example, increasing the closing timing of the electromagnetic spill valve 35 during the pressurization stroke, the amount of fuel discharged to the high-pressure fuel pipe 17a increases and the valve is closed. If the valve timing is delayed to shorten the valve closing period, the fuel discharge amount decreases.

  On the other hand, in the second high-pressure fuel pump 30b in which such discharge amount adjustment control is not performed, instead of the electromagnetic spill valve 35 described above, a portion between the pressurizing chamber 34 and the branch point 13 in the branch passage 14b is provided. A check valve 36 for preventing the return of fuel from the pressurizing chamber 34 side to the branch point 13 side is provided. The check valve 36 includes a valve element disposed in the valve chamber 31b and a spring that urges the valve element to close the valve hole.

  Therefore, in the second high pressure fuel pump 30b, during the intake stroke, the fuel from the fuel tank 10 side is supplied via the check valve 36, that is, the valve chamber 31b, according to the volume expansion of the pressurization chamber 34 by the plunger 33. It becomes inhaled in. In this check valve 36, the spring biasing force against the valve body is set to be extremely small so that the fuel suction period in the suction stroke is as close as possible to the volume expansion period of the pressurizing chamber 34 by the plunger 33 (to make it as long as possible). ing.

  In the pressurizing stroke, the fuel in the pressurizing chamber 34 is increased in pressure in accordance with the volume reduction of the pressurizing chamber 34 by the plunger 33, and when the fuel pressure exceeds a predetermined pressure, the check valve 19 is pushed open. The fuel is pumped to the high pressure fuel pipe 17b.

  Thus, in the present embodiment, the first high-pressure fuel pump 30a is provided with the electromagnetic spill valve 35, while the second high-pressure fuel pump 30b is not provided with a control means for adjusting the discharge amount. . According to this, when the operation of the first high-pressure fuel pump 30a is stopped and only the second high-pressure fuel pump 30b is operated, the opening / closing operation sound of the electromagnetic spill valve 35 does not occur at all. Further, even when both of the high-pressure fuel pumps 30a and 30b are operating, for example, the electromagnetic spill valve 35 is compared with a configuration in which the both high-pressure fuel pumps 30a and 30b are provided with the electromagnetic spill valve 35. The noise generated by the opening / closing operation can be suppressed as a whole.

  By the way, in the second high-pressure fuel pump 30b configured as described above, the amount of fuel discharged to the high-pressure fuel pipe 17b depends on the amount of change in the volume of the pressurizing chamber 34 accompanying the reciprocating movement of the plunger 33. It has become. That is, in the second high-pressure fuel pump 30b, the fuel discharge amount (fuel discharge amount per rotation of the camshaft 23) is constant.

  Therefore, when the required fuel amount (required fuel amount per rotation of the camshaft 23) in the internal combustion engine is smaller than the fuel discharge amount of the second high-pressure fuel pump 30b, the operation of the first high-pressure fuel pump 30a is performed. Even if the operation is stopped, useless energy is consumed regarding the difference between the fuel discharge amount and the required fuel amount.

  In the present embodiment, in order to suppress such wasteful energy consumption as much as possible, the fuel discharge amount of the second high-pressure fuel pump 30b is reduced, that is, the maximum discharge amount of the first high-pressure fuel pump 30a (the camshaft 23). The maximum discharge amount per rotation) is set to a small amount. In this way, for example, when the maximum discharge amount of the entire apparatus is the same as compared with the configuration in which the fuel discharge amount of the second high pressure fuel pump 30b is set larger than the maximum discharge amount of the first high pressure fuel pump 30a. In this case, it is possible to secure a wide adjustment range of the discharge amount.

  The setting of the fuel discharge amount of the second high-pressure fuel pump 30b will be described in more detail. In this embodiment, the fuel discharge amount is set to an amount substantially equal to the required fuel amount when the internal combustion engine is in the idling operation state. ing. Specifically, the fuel discharge amount of the second high-pressure fuel pump 30b is set to an amount obtained by adding a predetermined margin α (where α> 0) to the required fuel amount when in the idle operation state. By providing this margin, even if only the second high-pressure fuel pump 30b is responsible for fuel discharge when in the idle operation state, the fuel discharge amount as a whole device is sufficient for the required fuel amount. I have to.

  If the required fuel amount when the internal combustion engine is in the idling state is set through the discharge amount adjustment operation of the first high-pressure fuel pump 30a, the noise accompanying the adjustment operation, that is, the opening / closing operation of the electromagnetic spill valve 35 is performed. The noise that accompanies is unavoidable. On the other hand, when the required fuel amount during idling is ensured by fuel discharge by the second high-pressure fuel pump 30b, generation of noise due to the metering operation can be suppressed, but the discharge amount of the high-pressure fuel pump 30b is low. If the amount of fuel required during idle operation is exceeded, energy loss associated with the drive of the high-pressure fuel pump 30b will occur accordingly.

  In this regard, in this embodiment, when the internal combustion engine is in the idling operation state, the operation of the first high-pressure fuel pump 30a is stopped so that the minimum discharge amount as the entire device is substantially equal to the required fuel amount during the idling operation. Therefore, useless fuel discharge exceeding the required fuel amount during idle operation can be avoided as much as possible. As a result, wasteful energy consumption can be suppressed and fuel consumption can be improved.

  In the present embodiment, the margin α is set to a necessary minimum amount, thereby making the fuel discharge amount of the second high-pressure fuel pump 30b as close as possible to the required fuel amount during the idle operation. The wasteful fuel discharge exceeding the required fuel amount is avoided as much as possible.

  In addition, during idling, the combustion noise of the internal combustion engine is reduced, and other noises are relatively easily recognized by the driver. In this respect, according to the present embodiment, since the generation of noise associated with the discharge amount adjustment operation can be eliminated in a state where noise can be recognized relatively easily, the noise prevention effect becomes even more remarkable.

  Incidentally, in the first high-pressure fuel pump 30a configured as described above, when the amount of fuel to be discharged from the pump 30a is smaller than the maximum discharge amount, the difference fuel is supplied from the pressurizing chamber 34 to the valve. It will overflow to the chamber 31a side. Since such overflow occurs intermittently with the opening / closing operation of the electromagnetic spill valve 35, this causes the pressure pulsation propagating to the branch point 13 side to easily occur in the branch path 14a. When such a pressure pulsation reaches the branch point 13, there is a concern that the fuel intake of the second high-pressure fuel pump 30b, and thus the pump efficiency, may be adversely affected.

  In the present embodiment, for the purpose of avoiding such adverse effects, the length of the branch path 14a from the branch point 13 to the first high-pressure fuel pump 30a is the same as the branch path from the fuel supply path 12 to the second high-pressure fuel pump 30b. It is set longer than the length of 14b. According to this, such a pressure pulsation from the first high-pressure fuel pump 30 a is suitably damped before reaching the branch point 13. As a result, a decrease in pump efficiency in the second high-pressure fuel pump 30b can be suppressed.

Subsequently, a control system of the fuel supply apparatus for performing the operation control of the first high-pressure fuel pump 30a, that is, the discharge amount adjustment operation will be described.
As shown in FIG. 1, the control system of the fuel supply apparatus is configured around an electronic control unit (ECU) 40. The ECU 40 controls the operation state of the internal combustion engine, such as control of the fuel injection amount and fuel injection timing by the control of the injector 22, and also performs opening / closing control of the electromagnetic spill valve 35 as part thereof.

  The ECU 40 is configured as an arithmetic logic operation circuit including a central processing unit (CPU), a memory, and the like, and includes a port for input / output of signals with an external device. Detection signals from various sensors that detect the operating state of the internal combustion engine and the vehicle, such as a crank angle sensor 41, an intake pressure sensor 42, and an accelerator sensor 43, are input to the input port of the ECU 40, for example. The ECU 40 calculates various parameters indicating the engine operating state such as the load of the internal combustion engine and the engine rotation speed based on the detection signals of these sensors, and calculates the above-described required fuel amount in the internal combustion engine based on these. A fuel pressure sensor 44 attached to the high pressure fuel pipe 17b is also connected to the input port of the ECU 40, and the ECU 40 obtains the fuel pressure in the high pressure fuel pipes 17a and 17b based on the detection signal. On the other hand, signal lines to the injector 22, the electromagnetic spill valve 35, etc. are connected to the output port of the ECU 40, and command signals to them are output.

  The ECU 40 configured as described above adjusts the fuel discharge amount of the first high-pressure fuel pump 30a through the opening / closing control of the electromagnetic spill valve 35. In this control, the ECU 40 adjusts the fuel discharge amount of the first high-pressure fuel pump 30a according to the required fuel amount in the internal combustion engine. In particular, when the required fuel amount is equal to or less than the fuel discharge amount of the second high-pressure fuel pump 30b, the opening / closing operation of the electromagnetic spill valve 35 is stopped and the fuel discharge from the first high-pressure fuel pump 30a is stopped. ing. In this state, the fuel is discharged only by the second high-pressure fuel pump 30b. Therefore, the generation of noise accompanying the opening / closing operation of the electromagnetic spill valve 35 is completely prevented.

  FIG. 2 is a diagram showing the relationship between the energy consumption and the engine rotational speed as the whole apparatus regarding such fuel discharge in the fuel supply apparatus. A diagram 101 shown in the figure relates to a mode in which the fuel supply device of the present embodiment, that is, the first high-pressure fuel pump 30a and the second high-pressure fuel pump 30b are provided one by one. A diagram 201 is a comparative example with the present embodiment, in which a second high pressure fuel pump 30b is provided instead of the first high pressure fuel pump 30a, that is, one for each of the high pressure fuel pipes 17a and 17b. This relates to a mode in which the second high-pressure fuel pump 30b is made to correspond. A diagram 202 is also a comparative example with the present embodiment, in which a first high-pressure fuel pump 30a is provided in place of the second high-pressure fuel pump 30b, that is, for both the high-pressure fuel pipes 17a and 17b. This relates to a mode in which the first high-pressure fuel pumps 30a are associated one by one. In FIG. 2, regarding the relationship between the energy consumption and the engine rotational speed, this is shown in the speed range from the engine rotational speed v1 during idle operation to the relatively high engine rotational speed v3 during vehicle travel. Shall be shown.

  That is, in the mode corresponding to the diagram 201, this is constant without performing the metering regarding the fuel discharge amount as the whole apparatus. In this aspect, the energy consumption is larger than that in the other aspects over the entire region from the engine rotational speed v1 during idle operation to the high-speed engine rotational speed v3.

  On the other hand, in the mode corresponding to the diagram 202, the fuel discharge amount of the entire apparatus can be adjusted from the required fuel amount during idle operation to the required fuel amount during operation at the engine rotational speed v3. It is like that. Accordingly, the fuel discharge amount of the entire apparatus can be adjusted to an amount corresponding to the required fuel amount of the internal combustion engine over the entire region from the engine rotation speed v1 to the engine rotation speed v3. Energy consumption is avoided, and the amount of energy consumption is the smallest among the modes shown in FIG.

  In the present embodiment corresponding to the diagram 101, the energy consumption in the rotational range from the relatively low engine rotational speed v2 to the high-speed engine rotational speed v3 when the vehicle is running is an aspect corresponding to the diagram 202 described above. Although it is the same, the energy consumption tends to be larger than that in the above-described mode in the rotational range lower than the engine rotational speed v2. This is because the amount of fuel discharged from the second high-pressure fuel pump 30b is set to be larger by the margin α than the amount of fuel required during idle operation, and the first high-pressure fuel is used in a rotational range lower than the engine rotational speed v2. This is because even if the operation of the pump 30a is stopped, the fuel discharge amount of the entire apparatus exceeds the required fuel amount of the internal combustion engine.

  However, in the present embodiment, as compared with the above-described aspect corresponding to the diagram 202, although there is a difference regarding such energy consumption in the rotational range lower than the engine rotational speed v2, the first in the same rotational range. Since the operation of the high-pressure fuel pump 30a is stopped, no opening / closing operation sound of the electromagnetic spill valve 35 is generated. In the present embodiment, both pumps 30a and 30b are operated in the rotational range higher than the engine rotational speed v2, but only one of the electromagnetic spill valves 35 is operated in the same rotational range. It's just That is, as compared with the mode of the above-described diagram 202 in which the operation of the two electromagnetic spill valves 35 is required, it is possible to suppress the opening / closing operation sound of the electromagnetic spill valve 35 as a whole apparatus.

  In the above-described configuration, the first high pressure fuel pump 30a corresponds to a “metering high pressure fuel pump” and the second high pressure fuel pump 30b is a “non-metering high pressure fuel pump” in relation to the claims. It corresponds to.

In addition, embodiment is not limited above, For example, it is good also as the following aspects.
In the above embodiment, the stroke of the plunger 33 is made different between the pumps 30a and 30b so that the maximum discharge amount of the first high-pressure fuel pump 30a and the discharge amount of the second high-pressure fuel pump 30b are different. For example, the outer diameter of the plunger 33 may be varied (in this case, the inner diameter of the cylinder 32 is also changed).

  In the above-described embodiment, the discharge amount of the second high-pressure fuel pump 30b is set to an amount obtained by adding the margin α to the required fuel amount when the internal combustion engine is in the idling operation state. The amount may be equal to the required fuel amount when in the operating state.

  -In the first high-pressure fuel pump 30a, an electromagnetic spill valve 35 is used in which the valve body is driven by the electromagnetic force of the electromagnetic solenoid. To do. Such a limit causes a limit in the metering range of the discharge amount and becomes a factor of narrowing it. That is, for example, in the above-described embodiment in which the electromagnetic spill valve 35 is started to close when energization to the electromagnetic solenoid is started, the above limit easily acts so as to prevent the valve closing period from being shortened. The minimum discharge amount in the metering range is likely to deviate from the discharge amount (that is, “0”) when the pump 30a is stopped.

  For example, in a configuration in which all high-pressure fuel pumps are metered high-pressure fuel pumps, all metered high-pressure fuel pumps are stopped and set to “0” with respect to the discharge amount of the entire apparatus, or It is possible to operate only one metering type high-pressure fuel pump and set it as the lower limit control limit of the pump, that is, the minimum discharge amount. However, in this case, the discharge amount of the entire apparatus cannot be made smaller than this minimum discharge amount. Therefore, for the purpose of eliminating such a point, the discharge amount of the second high-pressure fuel pump 30b may be set to be smaller than the minimum discharge amount of the first high-pressure fuel pump 30a. According to this, by stopping the operation of the first high-pressure fuel pump 30a and performing the fuel discharge only by the second high-pressure fuel pump 30b, the discharge amount of the entire apparatus can be reduced. The amount can be made smaller than the minimum discharge amount. Therefore, when the required fuel amount of the internal combustion engine is smaller than the above-mentioned minimum discharge amount, the discharge amount of the entire apparatus is determined by the required fuel amount as compared with the configuration in which all the high-pressure fuel pumps are metering type high-pressure fuel pumps. It is possible to make the amount close, and finer adjustment of the discharge amount becomes possible.

  In the above-described embodiment, the electromagnetic spill valve 35 is configured to start closing when energization to the electromagnetic solenoid is started. However, the present invention is not limited to this, and the valve opening is started when starting energization. May be.

  In the above embodiment, the discharge amount of the second high-pressure fuel pump 30b is set to be smaller than the maximum discharge amount of the first high-pressure fuel pump 30a, but not limited to this, the maximum discharge amount of the first high-pressure fuel pump 30a The same or larger amount may be set.

  In the above embodiment, the operation of the first high pressure fuel pump 30a is stopped when the required fuel amount of the internal combustion engine is equal to or less than the discharge amount of the second high pressure fuel pump 30b. The first high-pressure fuel pump 30a may be operated, for example, by discharging in a quantity.

  In the above embodiment, the length of the branch path 14a from the branch point 13 to the first high-pressure fuel pump 30a in the fuel supply path 12 is greater than the length of the branch path 14b from the branch point 13 to the second high-pressure fuel pump 30b. However, the present invention is not limited to this. For example, both may be set to the same length, and the former may be set to be shorter than the latter.

  In the above embodiment, the spill valve that causes the overflow of fuel is adopted as the solenoid valve. However, the present invention is not limited to this. For example, in the intake stroke of the pump, the intake of the fuel is permitted / prohibited according to the opening / closing operation. A suction metering valve that performs this may be employed as the solenoid valve. The suction metering valve may be provided in place of the spill valve, or both of them may be provided.

  In the above embodiment, the discharge amount of the high-pressure fuel pump is adjusted based on the opening / closing operation of the solenoid valve. However, the present invention is not limited to this, and for example, the discharge amount is adjusted by changing the stroke of the plunger 33. You may make it do. In this case, for example, the cam profile for reciprocating the plunger 33 is inclined with respect to the axis of the camshaft 23, and the stroke of the plunger 33 is changed through control of the amount of movement of the shaft 23 in the axial direction.

  In the above embodiment, the high-pressure fuel pumps 30a and 30b are arranged separately in the middle of the branch paths 14a and 14b, that is, arranged in parallel in the fuel supply path 12. However, the present invention is not limited to this. One of the pumps 30a and 30b may be arranged in series, such as being arranged upstream of the other in the fuel supply path 12.

  -You may apply this invention to the fuel supply apparatus of an internal combustion engine provided with three or more high-pressure fuel pumps. In this case, as long as one or more metering type high-pressure fuel pumps and one or more non-metering type high-pressure fuel pumps are provided, the quantity relationship between them may be set in any way.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows schematically the fuel supply apparatus of the internal combustion engine of one Embodiment. The figure which shows the relationship between the energy consumption in the whole apparatus, and an engine speed.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Feed pump, 12 ... Fuel supply path, 13 ... Branch point, 14a, 14b ... Branch path, 17a, 17b ... High pressure fuel piping, 23 ... Cam shaft, 24a, 24b ... Pump cam, 30a ... 1st high pressure fuel Pump, 30b ... 2nd high pressure fuel pump, 33 ... Plunger, 34 ... Pressurizing chamber, 35 ... Electromagnetic spill valve, 40 ... Electronic control unit.

Claims (7)

In a fuel supply device for an internal combustion engine comprising a plurality of high-pressure fuel pumps for further pressurizing fuel supplied from a feed pump,
A fuel for an internal combustion engine, wherein a part of the plurality of high-pressure fuel pumps is a metering-type high-pressure fuel pump capable of adjusting a discharge amount, and the other pump is a non-metering-type high-pressure fuel pump. Feeding device. The fuel supply device for an internal combustion engine according to claim 1, wherein the metering type high-pressure fuel pump regulates a discharge amount through opening / closing control of a solenoid valve. The fuel supply device for an internal combustion engine according to claim 1 or 2, wherein a discharge amount of the non-metering type high pressure fuel pump is set to be smaller than a maximum discharge amount of the metering type high pressure fuel pump. The fuel supply device for an internal combustion engine according to claim 3, wherein a discharge amount of the non-metering type high-pressure fuel pump is set to be smaller than a minimum discharge amount in a metering range of the discharge amount of the metering type high-pressure fuel pump. When the required fuel amount in the internal combustion engine is equal to or less than the discharge amount of the non-metering type high-pressure fuel pump, the operation of the metering type high-pressure fuel pump is stopped and fuel discharge only by the non-metering type high-pressure fuel pump is performed. The fuel supply device for an internal combustion engine according to any one of claims 1 to 4. The fuel supply device for an internal combustion engine according to any one of claims 1 to 5, wherein a discharge amount of the non-metering type high-pressure fuel pump is set to a required fuel amount when the internal combustion engine is in an idle operation state. The metering-type high-pressure fuel pump is configured to meter the discharge amount through metering of at least one of the amount of fuel overflowing from the pressurizing chamber and the amount of fuel sucked into the pressurizing chamber,
Fuel from the feed pump is separately supplied to the high-pressure fuel pumps via a plurality of branch paths connected to the high-pressure fuel pumps, and the fuel from the branch point of the branch path to the metering-type high-pressure fuel pump. The fuel supply for the internal combustion engine according to any one of claims 1 to 6, wherein a length of the branch path is set to be longer than a length of the branch path from the branch point to the non-metering type high-pressure fuel pump. apparatus.

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