JP3752704B2 - Fuel supply device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel supply device that guides fuel in a fuel tank to a fuel injection valve provided in each cylinder of the engine body. In particular, the fuel in the fuel tank is increased in pressure by a high-pressure pump and guided to a fuel injection valve on the engine body side. The present invention relates to a fuel supply device for an internal combustion engine.
[0002]
[Prior art]
In general, an engine fuel supply system pressurizes fuel in a fuel tank with a low-pressure pump (feed pump) and supplies the fuel to a fuel injection valve of each cylinder of the engine body via a fuel pipe and a delivery pipe. Moreover, the surplus fuel that has not been consumed by the fuel injection valve is generally configured to return to the fuel tank via the return path.
By the way, in order to improve the responsiveness of the fuel supply and improve the controllability of the combustion, an in-cylinder injection engine in which fuel is directly injected into the cylinder by a fuel injection valve is known. The fuel supply system of this in-cylinder injection engine is known from Japanese Patent Laid-Open Nos. 7-77120 and 7-83134, and basically forms a fuel supply system as shown in FIG.
[0003]
Here, the fuel in the fuel tank 1 is pressurized by the feed pump 2 and led to the high pressure pump 5 via the check valve 3 and the filter 4, and the fuel pressure of the feed pump 2 is stabilized by the low pressure regulator 6. Further, the high-pressure pump 5 is driven by engine rotation and supplies pressurized fuel to each fuel injection valve 9 via the high-pressure pipe 7 and delivery pipe 8, and the high-pressure fuel is supplied by the fuel injection valve 9. Finely spray in the cylinder.
Here, surplus fuel that has passed through the delivery pipe 8 passes through the high-pressure regulator 10 to be reduced in pressure, and is returned to the fuel tank 1 through the low-pressure return path 11.
[0004]
In this case, when the engine is driven, the high-pressure pump 5 is always driven according to the engine rotation, and the driving force uses a part of the engine output. For this reason, the high pressure pump consumes a relatively large driving force at a high rotation speed, and when a part of the discharged fuel is returned to the fuel tank 1 as surplus fuel, a part of the driving force of the high pressure pump is wasted. Will be.
[0005]
[Problems to be solved by the invention]
In this way, in the high-pressure pump 5 that is always driven according to the engine rotation when the engine is driven, the discharge amount of surplus fuel per unit time varies depending on the engine operating range. For example, in the high-speed and low-load range, the high-pressure pump Compared with the amount of fuel discharged from the fuel, the amount of fuel injected and consumed by the fuel injection valve is very small, and most of the work performed by the high-pressure pump is converted into thermal energy and discharged as wasted work.
[0006]
For this reason, in the conventional fuel supply device, there are many ratios in which the high-pressure pump provided in the device is operated in an operation region that wastes engine output, resulting in a decrease in engine output and fuel consumption. Improvement is desired.
An object of the present invention is to provide a fuel supply device for a cylinder injection engine that can eliminate wasteful work of a high-pressure pump and prevent a decrease in engine output and fuel consumption due to driving of the high-pressure pump.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, a first aspect of the present invention is directed to a fuel passage provided between a fuel injection valve and a fuel tank, a high pressure pump provided in the fuel passage, and upstream of the high pressure pump. Holding means provided and holding the pressure of the high-pressure pump inlet;A delivery pipe for supplying the high-pressure fuel supplied from the high-pressure pump by branching to the fuel injection valves arranged in parallel with each other;It is provided downstream of the high pressure pump and discharged from the high pressure pump.Supplied to delivery pipePressure adjusting means for adjusting the fuel pressure, passage means for bypassing the high-pressure pump between the pressure adjusting means and the holding means to connect the inlet side and the outlet side thereof, and a control valve for opening and closing the passage means ,The control valve is opened at least at the time of starting or when the engine speed is a predetermined value or more.And a control means.
[0008]
  Claim2The invention of
  Claim1 describedIn a fuel supply device for an internal combustion engine,
The passage means is a return passage for returning fuel discharged from the high-pressure pump.
[0009]
  Claim3The invention of
  Claim 1Or claim 2In the fuel supply device for an internal combustion engine as described,
The pressure adjusting means is disposed between the fuel injection valve and the high pressure pump.
[0010]
  Claim4The invention of
  Claim 1Or claim 2In the fuel supply device for an internal combustion engine as described,
The pressure adjusting means isDelivery pipeIt is arranged downstream.
[0011]
  Claim5The invention of
  Claim3Or claim4In the fuel supply device for an internal combustion engine as described,
One end of the passage means is connected between the fuel injection valve and the high pressure pump.
[0012]
  Claim6The invention of
  Claim5In the fuel supply device for an internal combustion engine as described,
One end of the passage means isDelivery pipeIt is connected downstream.
[0013]
  Claim7The invention of
  Claims 1 to6In the fuel supply device for an internal combustion engine according to any one of
The holding means includes at least one of a feed pump, a check valve, and a low pressure regulator.
[0014]
  Claim8The invention of
  Claims 1 to6In the fuel supply device for an internal combustion engine according to any one of
The downstream end of the pressure adjusting means is connected to the vicinity of the upstream of the holding means.
[0015]
  Claim9The invention of
  Claims 1 to6In the fuel supply device for an internal combustion engine according to any one of
The downstream side of the pressure adjusting means is connected to a fuel tank.
[0016]
  Claim10The invention of
  Claims 1 to9In the fuel supply device for an internal combustion engine according to any one of
The control means opens the control valve when the discharge amount has a margin with respect to the set discharge amount set by the fuel amount injected by the fuel injection valve.
[0018]
  Claim11The invention of
  Claim8Or claim9In the fuel supply device for an internal combustion engine as described,
Bypass means for bypassing the pressure adjusting means at start-up is provided.
[0019]
  Claim12The invention of
  Claim11In the fuel supply device for an internal combustion engine as described,
A control valve is disposed in the passage means.
[0020]
  Claim13The invention of
  Claim12In the fuel supply device for an internal combustion engine as described,
Control means for opening the control valve at least at the time of starting or when the engine rotation is equal to or higher than a predetermined value is additionally provided.
[0021]
  Claim14The invention of
  Claim13In the fuel supply device for an internal combustion engine as described,
The control means closes the control valve in a range where the engine rotation is not more than a predetermined value after the start is completed.
[0022]
【Example】
  In FIG.First referenceThe fuel supply apparatus 20a of the cylinder injection engine as an example was shown.
  This in-cylinder engine fuel supply device 20a is attached to a fuel supply system of a four-cylinder DOHC gasoline engine (hereinafter simply referred to as an engine) 21 shown in FIGS. As shown in FIG. 1, the fuel supply device 20a includes a fuel passage 23 provided between the fuel injection valve I and the fuel tank 22, a high-pressure pump P2 provided in the fuel passage 23, and a high-pressure pump P2. A holding means 42 that is provided upstream and holds the pressure at the suction position c on the high pressure pump inlet side, and a pressure adjusting means that is provided downstream of the high pressure pump P2 and adjusts the fuel pressure discharged from the high pressure pump P2. A high pressure regulator R2 and a first return passage r1 as a passage means for bypassing the high pressure pump P2 and connecting the inlet side in and the outlet side ex between the high pressure regulator R2 and the pressure holding means 42 are provided.
[0023]
Here, as shown in FIG. 9, the engine 21 is mounted sideways in the engine room 24 at the front portion of the vehicle C, and the engine 21 and the front wheels 26 that are driving wheels are connected by a power transmission system 25. .
A fuel tank 22 is attached to the rear part of the vehicle C, and an electric feed pump P1 is attached in and around the tank, and the fuel in the fuel tank 22 is driven as shown in FIG. 1 when the feed pump P1 is driven. Then, the fuel is discharged into the fuel passage 23 through the check valve 27 and the filter 28.
[0024]
  In additionThe fuel tank 22 is provided with a relatively small canister (not shown) so as to adsorb a relatively small amount of evaporated fuel and perform a purge operation in a timely manner.
[0025]
As shown in FIG. 8, the engine 21 includes a cylinder block 30 into which a piston 29 is inserted at the center, and a cylinder head 31 and a head cover 32 are stacked on the upper portion of the cylinder block 30 in this order and integrally coupled. The cylinder head 31 is formed with intake / exhaust ports 35, 36 that are opened and closed by intake / exhaust valves 33, 34. In particular, the intake port 35 is formed long in the vertical direction, and the fuel injection valve I is formed at the side end of the intake port 35. And the fuel injection valve I enables direct fuel injection into the combustion chamber 37.
A fuel injection valve I is provided for each cylinder (see the broken line in FIG. 9). Each fuel injection valve I is longer than the delivery pipe 38 which is integrally attached to the cylinder head 31 in the engine longitudinal direction (vehicle width direction). High pressure fuel is supplied, valve opening operation is performed in accordance with a drive signal from an engine control unit (hereinafter simply referred to as ECU) 39a, and high pressure fuel can be atomized and sprayed.
[0026]
As shown by the solid line, the delivery pipe 38 of the in-cylinder injection engine fuel supply device shown in FIG. 1 is connected to a high-pressure portion 40 that receives the discharge pressure of the high-pressure pump P2, and is constantly supplied with high-pressure fuel during steady operation of the engine. Yes. The high-pressure part 40 is formed of high-pressure piping, and communicates the high-pressure pump P2 and the delivery pipe 38. The high-pressure pump P2 is directly moved by an exhaust camshaft (not shown) on the engine body side, and the number of rotations is increased or decreased according to the number of engine revolutions. Discharge to the side.
[0027]
Here, in the high-pressure unit 40, the fuel injection valve I and the high-pressure pump P2 branch, and the high-pressure regulator R2 and the return passage rp1 are connected thereto. The downstream end of the high pressure return path rp1 communicates with the downstream of the return path rd. The high pressure regulator R2 takes in the fuel pressure of the high pressure portion 40 at the pilot port a, and sets the fuel pressure of the high pressure portion 40 to a predetermined value in accordance with the balance operation of the plunger (not shown) that receives the fuel pressure and the biasing force of the compression spring (not shown) from the opposite direction. The pressure is adjusted, and surplus fuel passing through the high pressure regulator R2 is returned to the fuel tank 22.
Here, the fuel passage 23 between the discharge side position b of the filter 28 on the fuel tank 22 side and the suction position c of the high pressure pump P2, and the high pressure return passage rp1 and the return path rd between the high pressure regulator R2 and the fuel tank 22 are provided. 9 is piped in parallel along the longitudinal direction of the compartment 41 of the vehicle C, as shown in FIG.
[0028]
It is assumed that the engine 21 equipped with the fuel supply device 20a for the in-cylinder injection engine of FIG. 1 is started by turning on a key switch (not shown). In this case, first, the electric low-pressure pump P1 discharges the low-pressure fuel to the fuel passage 23 with good responsiveness. The low-pressure fuel that has reached the fuel passage 23 passes through the front check valve 43, is supplied to the suction position c of the high-pressure pump P2, bypasses the pump, and is delivered via the first return passage r1 via the high-pressure portion 40. It is supplied to each fuel injection valve I on the pipe 38 side, and when each fuel injection valve I receives a drive pulse of the ECU 39, it opens and causes gasoline in-cylinder injection to be performed, so that the engine 21 generates output torque. Yes.
In this case, when the fuel pressure is lower on the downstream side than on the upstream side of the high pressure pump P2, the low pressure fuel pressurized by the low pressure pump P1 is guided to the fuel injection valve I via the first return passage r1, thereby increasing the pressure. It is possible to prevent the pump P2 from being sufficiently driven at the time of starting and acting as a squeeze, and to improve startability.
[0029]
After this starting operation, during normal operation, the high pressure pump P2 is driven to some extent, so that the low pressure fuel is increased in pressure by the pressurizing operation of the high pressure pump P2 and supplied to the fuel injection valve I. The fuel pressure in the delivery pipe 38 and the high pressure section 40 is adjusted to a predetermined pressure by the high pressure regulator R2, and surplus fuel generated according to the engine speed passes through the high pressure regulator R2 and passes through the high pressure return passage rp1. It returns to the fuel tank 22 through a return path rd which is the downstream end of R1. In the operating range where the fuel consumption with respect to the pump discharge amount is relatively small and the surplus fuel increases, a part of the discharged fuel is returned from the inlet side in of the first return passage r1 to the outlet side ex. The fuel pressure on the outlet side ex is prevented from being lowered by the front check valve 43 which is the pressure holding means 42, and is again sucked and pressurized by the high pressure pump from the suction position c without greatly reducing the discharge pressure.
[0030]
For this reason, most of the excess fuel of the high pressure pump is sucked again by the high pressure pump from the suction position c without being reduced in pressure, and as a result, less energy is required for the pressurizing operation of the high pressure pump, and the high pressure pump is wasted. This can reduce the output of the engine and prevent the fuel consumption from deteriorating.
Further, most of the excess fuel of the high-pressure pump is returned to the first return passage r1, and as a result, the amount of fuel flowing down to the high-pressure return passage rp1 side by the pressure adjustment operation in the high-pressure regulator R2 is relatively reduced, and the temperature is increased. Can be reduced, the problem that the fuel temperature in the fuel tank 22 increases and the evaporated fuel increases, and the capacity of the canister (not shown) can be made relatively small.
In the in-cylinder injection engine fuel supply device of FIG. 1, the inlet side in and the outlet side ex are arranged so that the first return passage r1 bypasses only the high-pressure pump P2, but as a modified example instead of this, As indicated by a two-dot chain line in FIG. 1, the inlet side in and the outlet side ex may be disposed so as to bypass both the fuel injection valve I and the high pressure pump P2.
[0031]
  Also in the modification of the fuel supply device 20a of the direct injection engine, most of the excess fuel of the high pressure pump is sucked into the high pressure pump again from the suction position c without being greatly reduced in pressure after passing through the delivery pipe 38, as a result. The energy required for the pressurizing operation of the high-pressure pump can be reduced, and wasteful work of the high-pressure pump can be reduced, so that the engine output can be reduced and fuel consumption can be prevented from deteriorating.
  In FIG.Second referenceThe fuel supply apparatus 20b of the cylinder injection engine as an example was shown.
  This in-cylinder injection engine fuel supply device 20b includes many of the same members except for the difference in the configuration of the high-pressure return passage rp2 compared to the in-cylinder injection engine fuel supply device 20a of FIG. The same reference numerals are assigned to the same members, and duplicate descriptions are omitted.
[0032]
The fuel supply device 20b for the direct injection engine includes a high pressure regulator R2 that is provided downstream of the high pressure pump P2 and adjusts the fuel pressure discharged from the high pressure pump P2. Here, the downstream end of the delivery pipe 38 which is the high pressure section 40 and downstream of each fuel injection valve I is connected to the high pressure regulator R2, the high pressure return path rp2, and the return path rd.
The high pressure regulator R2 adjusts the fuel pressure of the high pressure section 40 after passing through the delivery pipe 38 to a predetermined value, and returns the surplus fuel passing through the high pressure regulator R2 to the fuel tank 22.
[0033]
The downstream end side of the delivery pipe 38 here extends from the high-pressure part 40. However, as shown by a two-dot chain line in FIG. Are formed in a U-shape and communicate with each other, and one end of the outer high-pressure portion 40 is sequentially communicated with the high-pressure regulator R2 and the high-pressure return passage rp2.
The downstream end of the high-pressure return passage rp2 is communicated with the fuel tank 22 via the return passage rd. However, in some cases, the downstream end of the high-pressure return passage rp2 is not connected to the return passage rd. It is directly connected between the low-pressure pump P1 upstream and the suction port position d (see the two-dot chain line in FIG. 2), so that the return fuel is not actively mixed with the fuel in the fuel tank 22, and the tank temperature You may suppress the rise of.
[0034]
Also in the case of the second embodiment, as in the first embodiment, the holding means 42 works effectively, and most of the excess fuel of the high-pressure pump is reduced in pressure through the first or second return passages r1 and r2. Without being sucked into the high-pressure pump again from the suction position c, wasteful work of the high-pressure pump can be reduced, engine output can be reduced, and fuel consumption can be prevented from deteriorating. In addition, the high pressure regulator R2 regulates the fuel pressure in the delivery pipe 38 and the high pressure passage 40 to a predetermined pressure, and returns excess fuel to the fuel tank 22 via the high pressure return passage rp2, but the high-temperature fuel is returned to the fuel tank 22. Therefore, the problem that the fuel temperature in the fuel tank 22 increases and the evaporated fuel increases can be reduced.
[0035]
  In FIG.Third referenceThe fuel supply apparatus 20c of the cylinder injection engine as an example was shown.
  The fuel supply device 20c for the in-cylinder injection engine is the same as the fuel supply device 20a for the in-cylinder injection engine of FIG. 1 except that the configurations of the high-pressure return passage rp2 and the first return passage r1 are different. In this example, the same members are denoted by the same reference numerals, and redundant description is omitted.
  The fuel supply device 20c for the in-cylinder injection engine includes a high-pressure regulator R2 and a high-pressure return passage rp3 that branch from between the high-pressure pump P2 and the delivery pipe 38 and adjust the fuel pressure discharged from the high-pressure pump P2. The high pressure return passage rp3 here is in communication with the upstream side of the front check valve 43.
[0036]
The high pressure regulator R2 adjusts the fuel pressure of the high pressure section 40 after passing through the delivery pipe 38 to a predetermined value, and returns excess fuel passing through the high pressure regulator R2 to the upstream side of the front check valve 43.
On the other hand, a first return passage r1 is provided that bypasses the high-pressure pump P2 between the high-pressure pump P2 and the fuel injection valve I and has an inlet side in and an outlet side ex. In particular, the outlet-side ex portion here is connected to the suction position c of the fuel passage 23 and communicates with a suction port (not shown) of the high-pressure pump P2. Note that the fuel supply device 20c for the direct injection engine in FIG. 3 has the inlet side in and the outlet side ex so that the first return passage r1 is bypassed only by the high pressure pump P2. As an example, the inlet side in and the outlet side ex may be disposed so as to bypass both the fuel injection valve I and the high pressure pump P2 as indicated by a two-dot chain line in FIG.
[0037]
  This thirdreferenceThe first example alsoreferenceAs in the example, the holding means 42 works effectively, and most of the excess fuel of the high-pressure pump passes through the first or second return passages r1 and r2 and is again sucked into the high-pressure pump P2 from the outlet side ex without being reduced in pressure. In addition, surplus fuel that passes through the high pressure regulator R2 is also sucked into the high pressure pump P2 from the suction position c, and waste work of the pump P2 can be more reliably reduced, and engine output reduction and fuel consumption deterioration can be prevented. In addition, the present apparatus 20c can eliminate the problem that the fuel at a high temperature is not returned to the fuel tank 22 and the fuel temperature in the fuel tank 22 increases and the evaporated fuel increases. Further, since the high-pressure return passage rp3 does not extend to the fuel tank 22 side, the piping is shortened and the cost can be reduced.
[0038]
  FIG. 4 shows the first aspect of the present invention.1An in-cylinder injection fuel supply apparatus 20d as an embodiment is shown.
  The fuel supply device 20d for the in-cylinder injection engine is the same as the fuel supply device 20c for the in-cylinder injection engine shown in FIG. 3 except that the configuration of the first or second return passages r1 and r2 is different. In many cases, the same members are denoted by the same reference numerals, and redundant description is omitted.
[0039]
The high pressure regulator R2 adjusts the fuel pressure of the high pressure section 40 after passing through the delivery pipe 38 to a predetermined value, and returns the surplus fuel passing through the high pressure regulator R2 to the suction position c. The first return passage r1 is a flow path that bypasses the high pressure pump P2, and connects the inlet side in that is the discharge side of the high pressure pump P2 and the outlet side ex that is the suction side via the switching valve means V that is a control valve. . The outlet side ex portion here communicates with the suction port of the high-pressure pump P2. In place of the first return passage r1 in FIG. 4, an inlet side in and an outlet side ex are provided so as to bypass both the fuel injection valve I and the high pressure pump P2 as shown by a two-dot chain line in FIG. May be.
[0040]
Here, an ECU 39d (which has the same configuration as the ECU 39a of FIG. 1 except that only a part of the control program is different) is connected to an electromagnetic actuator (not shown) of the switching valve means V. The ECU 39d as a control means for controlling the switching valve means V according to the operating state opens the switching valve means V when the internal combustion engine is started, and the engine speed is higher than a predetermined speed in a normal operating state other than the starting time. The switching valve means V is opened in the range, and the switching valve means V is closed in the low speed range where the engine speed is equal to or lower than the predetermined speed.
It should be noted that the valve opening allowable operation range in which the switching valve means V is allowed to open is set in accordance with each engine speed and load, and the operation state is within the valve opening allowable operation region. In this case, that is, in an operating state where a margin width ΔQ (excess fuel amount) is generated, a valve opening signal may be issued to the switching valve means V.
[0041]
Assume that the engine 21 equipped with the fuel supply device for the in-cylinder injection engine of FIG. 4 is started by turning on a key switch (not shown).
In this case, first, the electric low-pressure pump P1 discharges the low-pressure fuel to the fuel passage 23 with good responsiveness. The low-pressure fuel that has reached the fuel passage 23 bypasses the high-pressure pump P2 at the initial start and is added to the fuel injection valve I via the first return passage r1, and then the switching valve means V is closed and the high-pressure pump P2 is sucked in. The pressure is increased by the pressurizing operation, and is supplied to each fuel injection valve I on the delivery pipe 38 side through the high-pressure passage 40. When each fuel injection valve I receives a drive pulse from the ECU 39d, the opening operation is performed. Injection is executed, and output torque is generated in the engine 21. In this way, before the start is completed, the switching valve means V is turned on by the ECU 39d and held at the valve open position h2, the first return passage r1 is opened, the fuel pressure is increased quickly, and early start is possible.
[0042]
During normal operation after completion of the start-up, the switching valve means V is closed in the low speed range where the engine speed is equal to or lower than the predetermined speed, the capacity on the delivery pipe 38 side is narrowed, and the fuel pressure of the high-pressure unit 40 is reduced by the discharge amount of the high-pressure pump P2. Is increasing. When each engine speed reaches a high speed range equal to or higher than a predetermined speed, the ECU 39d outputs an ON signal to the switching valve means V to switch to the valve opening position h2, and opens the first return passage r1. At this time, surplus fuel in the high-pressure section 40 is returned to the outlet side ex via the first return passage r1, and the high-pressure level fuel is relatively stably supplied to the suction side of the high-pressure pump P2 by the action of the holding means 42. Is done. For this reason, it is possible to more reliably reduce useless work of the high-pressure pump P2 in the high rotation range during normal operation, and to prevent engine output reduction and fuel consumption deterioration. Moreover, since the surplus fuel that passes through the high pressure regulator R2 is not returned to the fuel tank 22, there is no problem that the fuel temperature in the fuel tank 22 increases and the evaporated fuel increases.
[0043]
  FIG. 5 shows the first aspect of the present invention.2An in-cylinder injection engine fuel supply device 20e as an example is shown.
  The fuel supply device 20e for the in-cylinder injection engine includes many of the same members except for the difference in the configuration of the high-pressure return passage rp2 compared to the fuel supply device 20d for the in-cylinder injection engine of FIG. The same reference numerals are assigned to the same members, and duplicate descriptions are omitted.
[0044]
The fuel supply device 20e for the in-cylinder injection engine includes a high pressure regulator R2 that is provided downstream of the high pressure pump P2 and the delivery pipe 38 and adjusts the fuel pressure discharged from the high pressure pump P2 and passing through the delivery pipe 38. Here, the downstream end of the delivery pipe 38 downstream of each fuel injection valve I is connected to the high pressure regulator R2, the high pressure return passage rp2, and the return passage rd.
In the case of this device 20e, the high pressure regulator R2 adjusts the fuel pressure of the high pressure section 40 after passing through the delivery pipe 38 to a predetermined value, and returns the surplus fuel passing through the high pressure regulator R2 to the fuel tank 22.
[0045]
Here again, the first return passage r1 connects the inlet side in which is the discharge side of the high-pressure pump P2 and the outlet side ex which is the suction side via the switching valve means V. The exit side ex portion here joins the suction position c of the fuel passage 23. In place of the first return passage r1 in FIG. 5, an inlet side in and an outlet side ex are provided so as to bypass both the fuel injection valve I and the high pressure pump P2 as shown by a two-dot chain line in FIG. May be.
Here, an ECU 39e (which has the same configuration as the ECU 39d in FIG. 4 except that only a control program is partially different) is connected to an electromagnetic actuator (not shown) of the switching valve means V. The ECU 39e as a control means for controlling the switching valve means V according to the operating state opens the switching valve means V at the start of the internal combustion engine and in a high speed range where the engine speed is equal to or higher than a predetermined speed. In the operating state, the switching valve means V is closed.
[0046]
It should be noted that the valve opening allowable operation range in which the switching valve means V is allowed to open is set in accordance with each engine speed and load, and the operation state is within the valve opening allowable operation region. In this case, that is, in an operating state where a margin width ΔQ (excess fuel amount) is generated, a valve opening signal may be issued to the switching valve means V.
Assume that the engine 21 equipped with the fuel supply device 20e for the cylinder injection engine of FIG. 5 is started by turning on a key switch (not shown).
[0047]
In this case, first, the electric low-pressure pump P1 discharges the low-pressure fuel to the fuel passage 23 with good responsiveness. The low-pressure fuel that has reached the fuel passage 23 bypasses the high-pressure pump P2 at the initial start, passes through the switching valve means V and the first return passage r1, and is added to the fuel injection valve I via the high-pressure portion 40. Thereafter, the switching valve means V is closed, and the low pressure fuel is increased in pressure by the suction and pressurization operation of the high pressure pump P2, and is supplied to each fuel injection valve I on the delivery pipe 38 side via the high pressure path 40, and each fuel injection valve I is connected to the ECU 39e. When the driving pulse is received, the opening operation is performed, in-cylinder injection of gasoline is executed, and the engine 21 generates output torque.
In particular, before the start is completed, the switching valve means V is turned on by the ECU 39e and held at the valve open position h2, the first return passage r1 is opened, and the fuel pressure on the delivery pipe 38 side is quickly increased, thereby enabling early start.
[0048]
During normal operation after completion of the start-up, in a low engine speed range where the engine speed is equal to or lower than the predetermined engine speed, the ECU 39e outputs an off signal to the switching valve means V to switch to the valve closing position h1, and the first return Close the passage r1. Thereby, the capacity | capacitance by the side of the delivery pipe 38 is narrowed, and it prevents that the fuel pressure of the high voltage | pressure part 40 falls. When the engine speed reaches a high speed range equal to or higher than a predetermined speed, the ECU 39d outputs an ON signal to the switching valve means V to switch to the valve opening position h2, and opens the first return passage r1. At this time, surplus fuel in the high-pressure section 40 is returned to the outlet side ex via the first return passage r1, and the high-pressure level fuel is relatively stable at the suction position c of the high-pressure pump P2 by the action of the holding means 42. Supplied. For this reason, the suction side fuel pressure of the high-pressure pump P2 is maintained at a high level during normal operation, and wasteful work can be more reliably reduced, and engine output reduction and deterioration of fuel consumption due to driving of the high-pressure pump P2 can be prevented. In addition, surplus fuel in the high-pressure section 40 is returned to the high-pressure pump P2 via the first return passage r1, so that the fuel returned to the fuel tank 22 via the high-pressure regulator R2 is reduced, and the fuel temperature in the fuel tank 22 is increased and evaporated. The problem of increased fuel is less likely to occur.
[0049]
  FIG. 6 shows the first aspect of the present invention.3An in-cylinder injection engine fuel supply device 20f as an example is shown.
  The fuel supply device 20f for the in-cylinder injection engine is different from the fuel supply device 20d for the in-cylinder injection engine shown in FIG. 4 in that the configurations of the high-pressure return path rp3 and the outlet side ex of the first return path r1 are different. The same members are denoted by the same reference numerals and redundant description is omitted here.
  The high pressure regulator R2 here regulates the fuel pressure of the high pressure section 40 to a predetermined value. The high pressure regulator R2 returns the surplus fuel passing through the high pressure regulator R2 to the suction position c via the high pressure return passage rp3. The high-pressure return passage rp3 includes a regulator bypass passage rb that is provided in parallel with the high-pressure regulator R2, and an on-off valve B is attached to the passage rb. The electromagnetic actuator (not shown) of the on-off valve B is connected to an ECU 39f (takes the same configuration as the ECU 39d in FIG. 4 except that only the control program is partially different).
[0050]
The first return passage r1 connects the inlet side in which is the discharge side of the high-pressure pump P2 and the outlet side ex which is the suction side via the switching valve means V which is a control valve. Here, the outlet side ex portion and the suction position c of the fuel passage 23 are arranged in parallel to each other, and both communicate with the suction port of the high-pressure pump P2. In place of the first return passage r1 in FIG. 6, an inlet side in and an outlet side ex are arranged so as to bypass both the fuel injection valve I and the high pressure pump P2 as shown by a two-dot chain line in FIG. May be.
[0051]
Here, the ECU 39f is connected to an electromagnetic actuator (not shown) of the switching valve means V. The ECU 39f as a control means for controlling the on-off valve B and the switching valve means V in accordance with the operating state closes the switching valve means V when the internal combustion engine is started, opens the on-off valve B, and operates in the normal operating state other than at the start. The switching valve means V and the on-off valve B are closed in a low speed range where the rotational speed is less than or equal to a predetermined speed, and the switching valve means V is closed and the switching valve means V is opened in a high speed range above the predetermined speed. It should be noted that the valve opening allowable operation range in which the switching valve means V is allowed to open is set in accordance with each engine speed and load, and the operation state is within the valve opening allowable operation region. In this case, that is, in an operating state where a margin width ΔQ (excess fuel amount) is generated, a valve opening signal may be issued to the switching valve means V.
[0052]
Assume that the engine 21 equipped with the fuel supply device 20f for the in-cylinder injection engine of FIG. 6 is started by turning on a key switch (not shown).
In this case, first, the electric low-pressure pump P1 discharges the low-pressure fuel to the fuel passage 23 with good responsiveness. The low-pressure fuel that has reached the fuel passage 23 passes through the high-pressure return passage rp3, the regulator bypass passage rb, and the on-off valve B, is supplied to the high-pressure section 40, and is added to each fuel injection valve I on the delivery pipe 38 side. Further, each fuel injection valve I is opened when a drive pulse of the ECU 39d is received, in-cylinder injection of gasoline is executed, and output torque is generated in the engine 21.
In particular, before the start is completed, the switching valve means V is turned off by the ECU 39f and held at the valve closing position h1, the first return passage r1 is closed, the capacity on the delivery pipe 38 side is narrowed, and at the same time, the opening / closing valve B is opened. By switching to, the low-pressure fuel is added to the high-pressure unit 40, so that the fuel pressure is increased quickly, fuel movement is promoted, and early start is possible.
[0053]
During normal operation after the start is completed, the ECU 39f outputs an OFF signal to the switching valve means V and the on-off valve B in the predetermined speed range where the engine speed is equal to or lower than the predetermined speed, and the first return is set as the valve closing positions h1, k1. The passage r1 and the regulator bypass rb are closed. Thereby, the discharge pressure of the high-pressure pump P2 can be secured, and the spray of the fuel injection valve I can be stabilized. When the engine speed reaches a high speed range equal to or higher than the predetermined speed, the ECU 39f outputs an ON signal to the switching valve means V to switch to the valve opening position h2, and opens the first return passage r1. At this time, surplus fuel in the high-pressure section 40 is returned to the outlet side ex via the first return passage r1, and high-pressure level fuel is relatively stably supplied to the suction side of the high-pressure pump P2. The on-off valve B is switched to the closed position k1, and maintains the fuel pressure on the high pressure unit 40 side at a predetermined level.
[0054]
  For this reason, the wasteful work of the high-pressure pump P2 can be more reliably reduced during normal operation, and the fuel can be refined by promoting the appropriate combustion by ensuring a predetermined fuel pressure, thereby preventing engine output reduction and fuel consumption deterioration. it can. In addition, since the surplus fuel is returned to the downstream side of the front check valve 43 via the high pressure regulator R2, a part of the fuel supplied to the high pressure pump P2 can be secured, and the high-temperature fuel is returned to the fuel tank 22. Therefore, there is no problem that the fuel temperature in the fuel tank 22 increases and the evaporated fuel increases. Furthermore, it is not necessary to extend the high-pressure return passage rp3 to the fuel tank 22, and the cost can be reduced.
  FIG. 7 shows the first aspect of the present invention.4An in-cylinder injection engine fuel supply device 20g as an example is shown.
[0055]
The fuel supply device 20g for the in-cylinder injection engine includes many of the same members except for the difference in the configuration of the high-pressure return passage rp2 compared to the fuel supply device 20e for the in-cylinder injection engine of FIG. The same reference numerals are assigned to the same members, and duplicate descriptions are omitted.
The in-cylinder injection engine fuel supply device 20g includes, in particular, a high-pressure regulator R2 that adjusts the fuel pressure that has passed through the delivery pipe 38, and the downstream end of the delivery pipe 38 that is downstream of each fuel injection valve I is the high-pressure regulator R2. , Connected to the high pressure return path rp2 and the return path rd.
[0056]
In the case of this device 20g, the high pressure regulator R2 adjusts the fuel pressure of the high pressure section 40 after passing through the delivery pipe 38 to a predetermined value, and returns the surplus fuel passing through the high pressure regulator R2 to the fuel tank 22. The high-pressure return passage rp2 includes a regulator bypass passage rb that is provided in parallel with the high-pressure regulator R2, and an on-off valve B is mounted on the passage rb. Further, an orifice OS is provided downstream of the on-off valve B. The electromagnetic actuator (not shown) of the on-off valve B is connected to an ECU 39g (takes the same configuration as the ECU 39e in FIG. 5 except that only a control program is partially different).
Here again, the first return passage r1 connects the inlet side in which is the discharge side of the high-pressure pump P2 and the outlet side ex which is the suction side via the switching valve means V. The exit side ex portion here joins the suction position c of the fuel passage 23.
[0057]
Here, the ECU 39g is connected to an electromagnetic actuator (not shown) of the switching valve means V. The ECU 39g as a control means for controlling the on-off valve B and the switching valve means V according to the operating state closes the switching valve means V when the internal combustion engine is started, opens the on-off valve B, and in the normal operating state other than the starting time, the engine The function of closing the on-off valve B and the switching valve means V in the low speed range where the rotational speed is equal to or lower than the predetermined speed, and closing the on-off valve B and opening the switching valve means V in the high speed range where the engine speed is higher than the predetermined speed. Is provided.
In place of the first return passage r1 in FIG. 7, an inlet side in and an outlet side ex are arranged so as to bypass both the fuel injection valve I and the high pressure pump P2 as shown by a two-dot chain line in FIG. In this case, in order to remove bubbles remaining in the delivery pipe 38 and the like at the start, it is preferable to set the switching valve means V to be closed at the start.
[0058]
It should be noted that the valve opening allowable operation range in which the switching valve means V is allowed to open is set in accordance with each engine speed and load, and the operation state is within the valve opening allowable operation region. In this case, that is, in an operating state where a margin width ΔQ (excess fuel amount) is generated, a valve opening signal may be issued to the switching valve means V.
Assume that the engine 21 equipped with the fuel supply device 20g for the in-cylinder injection engine of FIG. 7 is started by turning on a key switch (not shown).
[0059]
In this case, first, the electric low-pressure pump P1 discharges the low-pressure fuel to the fuel passage 23 with good responsiveness. The low-pressure fuel that has reached the fuel passage 23 bypasses the high-pressure pump P2 at the start of the start, passes through the switching valve means V and the first return passage r1, and is added to the fuel injection valve I via the high-pressure portion 40. Thereafter, in the low rotation range, the switching valve means V is closed, the pressure is increased by the suction and pressurization operation of the high pressure pump P2, and is supplied to each fuel injection valve I on the delivery pipe 38 side via the high pressure path 40. Is opened when the ECU 39g receives a drive pulse, causing gasoline to be injected into the cylinder and causing the engine 21 to generate output torque.
[0060]
In particular, before the start is completed, the switching valve means V is turned on by the ECU 39g and held at the valve open position h2, the first return passage r1 is opened, the fuel pressure on the delivery pipe 38 side is quickly raised, fuel movement is promoted, and early Start is possible. At the same time, the on-off valve B is switched to the open position k2 to reliably remove bubbles remaining in the delivery pipe 38 and the like. Further, a pressure slightly lower than the fuel pressure set by the low pressure regulator R1 is set on the high pressure portion 40 side upstream of the regulator bypass rb due to the presence of the orifice OS, so that the fuel supply amount at the start can be accurately adjusted. Become.
During normal operation after the start is completed, in the low speed range where the engine speed is equal to or lower than the predetermined speed, the ECU 39g outputs an OFF signal to the switching valve means V and the on-off valve B to output the first return passage r1 and the regulator bypass passage. Close rb. In this case, the fuel pressure applied to the fuel injection valve I can be adjusted by the high-pressure regulator R2, and stable high-pressure injection is possible.
[0061]
When the engine speed reaches a high speed range equal to or higher than the predetermined speed, the ECU 39g outputs an ON signal to the switching valve means V to switch to the valve opening position h2, and opens the first return passage r1. At this time, the surplus fuel returned to the outlet side ex through the first return passage r1 is held at a high pressure level by the action of the holding means 42, and is supplied relatively stably to the suction side of the high pressure pump P2. At the same time, the on-off valve B is switched to the closed position k1, and the fuel pressure on the high pressure part 40 side is held at a predetermined level. Excess fuel in the high pressure section 40 is returned to the fuel tank 22 via the high pressure regulator R2.
For this reason, the wasteful work of the high-pressure pump P2 can be more reliably reduced during normal operation, and the fuel can be refined by promoting the appropriate combustion by ensuring a predetermined fuel pressure, thereby preventing engine output reduction and fuel consumption deterioration. it can. In addition, surplus fuel in the high-pressure section 40 is returned to the high-pressure pump P2 via the first return passage r1, so that the fuel returned to the fuel tank 22 via the high-pressure regulator R2 is reduced, and the fuel temperature in the fuel tank 22 is increased and evaporated. The problem of increased fuel is less likely to occur.
[0062]
The present invention is not limited to the above-described embodiments. For example, in the above description, the engine 21 is mounted on the fuel supply system of a four-cylinder DOHC gasoline engine. It can be mounted on a cylinder gasoline engine or a multi-cylinder engine using alcohol fuel other than gasoline. The present invention can also be applied to a diesel engine having a known unit injector. It can also be applied to an intake port injection type engine. Further, each of the above-described high-pressure pumps is an engine drive type, but may be a motor drive type. In this case, the startability is not particularly a problem. Therefore, in the fuel supply system (for example, see the control valve in FIGS. 4 to 7) provided with the control valve in the first return passage r1, the control valve is controlled according to the engine load. It ’s fine.
[0063]
【The invention's effect】
  As described above, according to the first aspect of the present invention, the control valve is disposed in the passage means, and the control meansLessIn both cases, since the control valve is opened when starting or when the engine speed is equal to or higher than a predetermined value, it is possible to start the engine at an early stage and to reduce unnecessary work of the high-pressure pump in the high engine speed range.
[0064]
  Claim2The invention of
  Claim1In the internal-combustion-engine fuel supply apparatus described above, in particular, since the passage means is set as a return passage for returning the fuel discharged from the high-pressure pump, this return passage can reduce unnecessary work of the high-pressure pump.
[0065]
  Claim3The invention of
  Claim 1Or claim 2In the fuel supply device for an internal combustion engine described above, in particular, the pressure adjusting means can adjust the fuel pressure between the fuel injection valve and the high-pressure pump. For this reason, the pressure of the fuel from the high pressure pump can be maintained at an appropriate value, and the spray of the fuel injection valve can be stabilized.
[0066]
  Claim4The invention of
  Claim 1Or claim 2In the fuel supply apparatus for an internal combustion engine described above, in particular, the pressure adjusting meansDelivery pipeThe downstream fuel pressure can be adjusted. For this reason, the pressure of the fuel from the high pressure pump can be maintained at an appropriate value, and the spray of the fuel injection valve can be stabilized.
[0067]
  Claim5The invention of
  Claim3Or claim4In the fuel supply device for an internal combustion engine described above, in particular, since one end of the passage means is connected between the fuel injection valve and the high-pressure pump, surplus fuel from the high-pressure pump is returned again to the suction side of the high-pressure pump. Unnecessary work can be reduced.
[0068]
  Claim6The invention of
  Claim5In the fuel supply device for an internal combustion engine described above, in particular, one end of the passage means isDelivery pipeSince it is connected downstream, surplus fuel that has not been consumed by the fuel injection valve is returned to the suction side of the high-pressure pump again, and wasteful work of the high-pressure pump can be reduced.
[0069]
  Claim7The invention of
  Claims 1 to6In the fuel supply apparatus for an internal combustion engine according to any one of the above, in particular, since the holding means is composed of at least one of a feed pump, a check valve, and a low pressure regulator, the pressure of the excess fuel from the high pressure pump is maintained. It is reliably held by the means, and wasteful work of the high-pressure pump can be reduced.
[0070]
  Claim8The invention of
  Claims 1 to6In the fuel supply device for an internal combustion engine according to any one of the above, in particular, since the downstream end of the pressure adjusting means is connected in the vicinity of the upstream of the holding means, excess fuel does not return to the fuel tank side, The fuel temperature is not increased, and the piping can be set short to reduce the cost.
[0071]
  Claim9The invention of
  Claims 1 to6In the fuel supply apparatus for an internal combustion engine according to any one of the above, in particular, the downstream of the pressure adjusting means may be connected to a fuel tank, and in this case also, the surplus fuel from the high pressure pump is again supplied to the high pressure pump by the passage means. It is possible to reduce the wasteful work of the high-pressure pump by returning to the suction side.
[0072]
  Claim10The invention of
  Claims 1 to9In the fuel supply device for an internal combustion engine according to any one of the above, the control means opens the control valve when the discharge amount has a margin with respect to the set discharge amount set by the fuel amount injected by the fuel injection valve. Only when the high-pressure pump is driven with a margin for the set discharge amount, the fuel is sucked back to the suction side through the passage means, so that unnecessary work of the high-pressure pump can be reduced.
[0074]
  Claim11The invention of
  Claim8 or claim 9In the internal-combustion-engine fuel supply apparatus described above, in particular, a bypass means for bypassing the pressure adjusting means at the time of start-up is provided, so that the fuel flow at the time of start-up can be performed smoothly and startability can be improved.
[0075]
  Claim12The invention of
  Claim11In the internal combustion engine fuel supply apparatus described above, in particular, since the control valve is disposed in the passage means, the flow resistance of the passage means can be reduced at a predetermined time, and the fuel flow at the predetermined time can be smoothly performed.
[0076]
  Claim13The invention of
  Claim12In the fuel supply device for an internal combustion engine described above, in particular, the control valve is provided with a control means that opens at least at the time of starting or when the engine speed is a predetermined value or less, so that startability can be improved, and in the high engine speed range. Unnecessary work of the high-pressure pump can be reduced.
[0077]
  Claim14The invention of
  Claim13In the internal-combustion engine fuel supply apparatus described above, the control means closes the control valve in a range where the engine rotation is not more than a predetermined value since the start is completed. Can be secured, and the spray of the fuel injection valve can be stabilized.
[Brief description of the drawings]
[Figure 1]First reference exampleIt is a schematic block diagram of the fuel supply apparatus of the cylinder injection engine as.
[Figure 2]Second reference exampleIt is a schematic block diagram of the fuel supply apparatus of the cylinder injection engine as.
[Fig. 3]Third reference exampleIt is a schematic block diagram of the fuel supply apparatus of the cylinder injection engine as.
FIG. 4 shows the first aspect of the present invention.1It is a schematic block diagram of the fuel supply apparatus of the cylinder injection engine as an Example.
FIG. 5 shows the first of the present invention.2It is a schematic block diagram of the fuel supply apparatus of the cylinder injection engine as an Example.
FIG. 6 shows the first of the present invention.3It is a schematic block diagram of the fuel supply apparatus of the cylinder injection engine as an Example.
FIG. 7 shows the first of the present invention.4It is a schematic block diagram of the fuel supply apparatus of the cylinder injection engine as an Example.
FIG. 8 is a longitudinal sectional view of a direct injection engine as the first embodiment of the present invention.
FIG. 9 is a schematic layout diagram of a vehicle equipped with an in-cylinder injection engine as a first embodiment of the present invention.
FIG. 10 is a schematic configuration diagram of a conventional fuel supply device for a direct injection engine.
[Explanation of symbols]
  20a-20g Fuel supply device for in-cylinder injection engine
  21 engine
  22 Fuel tank
  23 Fuel passage
  38 Delivery pipe
  39a, 39d, 39e, 39f, 39g
                  ECU
  40 High pressure section
  42 Holding means
  43 Front check valve
  c Suction position
  b Discharge side position
  e Pilot port
  in entrance side
  ex Exit side
  rd return passage
  r1 first return passage
  r2 Second return passage
  rp1, rp2, rp3
                  High pressure return passage
  I Fuel injection valve
  P1 feed pump
  P2 high pressure pump
  R1 Low pressure regulator
  R2 high pressure regulator
  V switching valve means
  B Open / close valve

Claims (14)

A fuel passage provided between the fuel injection valve and the fuel tank;
A high-pressure pump provided in the fuel passage;
A holding means that is provided upstream of the high-pressure pump and holds the pressure of the high-pressure pump inlet;
A delivery pipe for supplying the high-pressure fuel supplied from the high-pressure pump by branching to the fuel injection valves arranged in parallel with each other;
A pressure adjusting means provided downstream of the high pressure pump, for adjusting the fuel pressure discharged from the high pressure pump and supplied to the delivery pipe ;
Passage means for bypassing the high-pressure pump between the pressure adjusting means and the holding means and connecting the inlet side and the outlet side thereof;
A control valve for opening and closing the passage means;
A fuel supply device for an internal combustion engine, comprising: a control means for opening the control valve at least when starting or when the engine speed is equal to or higher than a predetermined value . The fuel supply device for an internal combustion engine according to claim 1,
The fuel supply device for an internal combustion engine, wherein the passage means is a return passage for returning the fuel discharged from the high-pressure pump . The fuel supply device for an internal combustion engine according to claim 1 or 2,
A fuel supply apparatus for an internal combustion engine, wherein the pressure adjusting means is disposed between a fuel injection valve and a high pressure pump . The fuel supply device for an internal combustion engine according to claim 1 or 2 ,
A fuel supply apparatus for an internal combustion engine, wherein the pressure adjusting means is disposed downstream of a delivery pipe . The fuel supply device for an internal combustion engine according to claim 3 or 4 ,
A fuel supply device for an internal combustion engine , wherein one end of the passage means is connected between a fuel injection valve and a high pressure pump . The fuel supply device for an internal combustion engine according to claim 5 ,
A fuel supply apparatus for an internal combustion engine, wherein one end of the passage means is connected downstream of a delivery pipe . The fuel supply device for an internal combustion engine according to any one of claims 1 to 6 ,
The fuel supply apparatus for an internal combustion engine , wherein the holding means is composed of at least one of a feed pump, a check valve, and a low pressure regulator . The fuel supply device for an internal combustion engine according to any one of claims 1 to 6 ,
A fuel supply apparatus for an internal combustion engine, characterized in that the downstream end of the pressure adjusting means is connected in the vicinity of the upstream of the holding means . The fuel supply device for an internal combustion engine according to any one of claims 1 to 6 ,
A fuel supply apparatus for an internal combustion engine, wherein a downstream of the pressure adjusting means is connected to a fuel tank . The fuel supply device for an internal combustion engine according to any one of claims 1 to 9 ,
The fuel supply apparatus for an internal combustion engine, wherein the control means opens the control valve when the discharge amount has a margin with respect to a set discharge amount set by the fuel amount injected by the fuel injection valve . The fuel supply device for an internal combustion engine according to claim 8 or 9 ,
A fuel supply apparatus for an internal combustion engine, comprising bypass means for bypassing the pressure adjusting means at start-up . The fuel supply device for an internal combustion engine according to claim 11 ,
A fuel supply device for an internal combustion engine , wherein a control valve is disposed in the passage means . The fuel supply device for an internal combustion engine according to claim 12,
A fuel supply apparatus for an internal combustion engine, comprising a control means for opening the control valve at least when starting or when the engine rotation is greater than a predetermined value . The fuel supply device for an internal combustion engine according to claim 13,
The fuel supply device for an internal combustion engine, wherein the control means closes the control valve in a range where the engine rotation is not more than a predetermined value after the start is completed .

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