JP3882207B2 - Fuel supply device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel supply device in a system that supplies fuel from a fuel tank to an engine via a fuel injection valve, particularly a cylinder injection engine in which a fuel injection valve is provided in each cylinder of the engine. The present invention relates to a fuel supply device for an internal combustion engine that requires a high injection pressure.
[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. In addition, 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, piping on the fuel injection valve side of the fuel supply system is likely to receive heat from the engine body. Particularly, when the atmospheric temperature of the engine is relatively high, the fuel returning from the return path is likely to become high temperature, and the amount of evaporated fuel increases.
[0003]
In order to cope with this, the evaporated fuel generated in the fuel tank is adsorbed by an adsorbent such as activated carbon in the canister and liquefied to prevent high pressure in the fuel tank. Is sent to the intake system, and the canister is purged.
Incidentally, an in-cylinder injection gasoline engine is known in which gasoline fuel is injected directly into a cylinder by a fuel injection valve in order to improve the responsiveness of fuel supply and the controllability of combustion. The fuel supply system of this in-cylinder injection engine is known in Japanese Patent Laid-Open Nos. 7-77120 and 7-83134, and basically forms a fuel supply system as shown in FIG.
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.
[0004]
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. Reference numeral 12 denotes a high-pressure pump bypass passage provided with a check valve 15, and reference numeral 13 denotes a high-pressure regulator bypass passage provided with an on-off valve 14. In this case, the rise of the fuel pressure of the high-pressure pump 5 is delayed when the engine is started. Meanwhile, the relatively low-pressure fuel of the electric feed pump 2 is supplied to the delivery pipe 8 through the high-pressure pump bypass 12, and surplus fuel is supplied to the on-off valve 14. Is returned to the return path 11 through the open high-pressure regulator bypass path 13 to ensure startability. During normal operation after startup, the high-pressure regulator bypass 13 is closed, the fuel in the fuel tank 1 is sequentially pressurized by the feed pump 2 and the high-pressure pump 5, and returned to the return path 11 via the high-pressure regulator 10.
[0005]
In this way, in particular, in the fuel supply system of the direct injection engine, the fuel is pressurized by the high pressure pump 5, so that surplus fuel returning from the fuel injection valve 9 to the return path 11 is compared with the case of the conventional intake port injection. As a result of the increased pressure, the temperature tends to increase, and when the high-temperature fuel returns to the fuel tank, a relatively large amount of evaporated fuel is generated. To cope with this, a relatively large canister needs to be provided.
[0006]
[Problems to be solved by the invention]
As described above, the piping on the fuel injection valve side of the fuel supply system is susceptible to the heat of the engine body when the engine ambient temperature is relatively high. In particular, in the case of an in-cylinder injection engine, the engine supply atmosphere In addition to the temperature, heat generated by high compression is also added, so that the fuel returning from the return path tends to have a higher temperature, and a relatively large amount of evaporated fuel tends to be generated. In order to cope with this, simply increasing the size of the canister has a limit in terms of layout and purging, and an improvement for preventing evaporation more appropriately is desired.
[0007]
In addition, a large number of pipes are connected to the high-pressure pump that is driven directly by the engine, and the piping structure around the high-pressure pump is complicated, and problems are likely to occur in terms of improving workability in terms of layout. It is desired.
An object of the present invention is to provide a fuel supply device for an internal combustion engine that can regulate the generation of evaporated fuel in a fuel tank and simplify piping of a fuel supply system.
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, the invention of claim 1
  A low pressure pump interposed in a fuel passage connecting the fuel injection valve and the fuel tank;
A high-pressure pump provided between the low-pressure pump and the fuel injection valve;
  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;
  Fuel pressure adjusting means provided downstream of the delivery pipe so that the fuel pressure supplied to the fuel injection valve is adjusted to a set pressure;
  A high pressure return passage for returning surplus fuel passing through the fuel pressure adjusting means to a fuel passage between the high pressure pump and the low pressure pump;And
A second return passage branched from the high pressure return passage and connected downstream to the fuel tank is disposed;
Switching valve means for switching so as to guide the surplus fuel to either the downstream end of the high pressure return passage or the second return passage is provided.It is characterized by.
[0013]
  Claim2The invention of
  Claim1In the fuel supply device for an internal combustion engine as described,
  The switching valve means includes control means for controlling the excess fuel to be switched upstream of the high-pressure pump in a normal operation state of the internal combustion engine and to a second return passage in a specific operation state.
[0014]
  Claim3The invention of
  Claim1In the fuel supply device for an internal combustion engine as described,
  A bypass passage connecting the upstream and downstream fuel passage portions of the fuel pressure adjusting means is disposed;
  An on-off valve for opening and closing the bypass passage is provided.
[0015]
  Claim4The invention of
  Claim3In the fuel supply device for an internal combustion engine as described,
  The on-off valve includes control means for controlling opening and closing so that the internal combustion engine is closed in a normal operation state and opened in a specific operation state.
[0016]
  Claim5The invention of
  Claim2Or claim4In the fuel supply device for an internal combustion engine as described,
  The specific operation state is a state where the discharge pressure of the high-pressure pump is not sufficient.
[0017]
  Claim6The invention of
  Claim5In the fuel supply device for an internal combustion engine as described,
  The high-pressure pump is driven by the internal combustion engine, and the specific operation state is when the internal combustion engine is started.
[0024]
  Claim7The invention of
  Claim1In the fuel supply device for an internal combustion engine as described,
  A fuel supply device for an internal combustion engine, comprising a low pressure return passage for returning fuel upstream of the high pressure pump to the fuel tank via the low pressure fuel adjusting means.
[0025]
  Claim8The invention of
  Claim7In the fuel supply device for an internal combustion engine as described,
  The upstream side of the low pressure return passage is located on the downstream side of the high pressure return passage and the upstream side of the upstream end of the second bypass passage.
[0026]
  Claim9The invention of
  Claim8In the fuel supply device for an internal combustion engine as described,
  An internal combustion engine characterized in that an upstream side of the low pressure return passage is provided close to the low pressure pump, and a downstream end of the high pressure return passage and an upstream end of the second bypass passage are provided close to the high pressure pump. Fuel supply device.
[0028]
【Example】
FIG. 1 shows a fuel supply device 20a for a direct injection engine as a first embodiment of the present invention.
This in-cylinder injection engine fuel supply device 20a is mounted on a fuel supply system of a four-cylinder DOHC gasoline engine (hereinafter simply referred to as an engine) 21 shown in FIGS. 9 and 10, and includes a fuel injection valve I and a fuel tank 22. The low pressure pump P1 interposed in the fuel passage 23 to be connected, the high pressure pump P2 provided between the low pressure pump P1 and the fuel injection valve I, and the fuel pressure supplied to the fuel injection valve I are adjusted to the set pressure. Therefore, a high pressure regulator R2 as a fuel pressure adjusting means provided in parallel with the fuel injection valve I, and a high pressure for returning surplus fuel passing through the high pressure regulator R2 to the fuel passage 23 between the high pressure pump P2 and the low pressure pump P1. And a return passage r2.
[0029]
Here, as shown in FIG. 10, 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 mounted at the rear of the vehicle C, and a low-pressure pump P1 as an electric feed pump is mounted in the tank. The fuel in the fuel tank 22 is shown in FIG. 1 when the low-pressure pump P1 is driven. As described above, the fuel is discharged into the fuel passage 23 through the check valve 27 and the filter 28. The 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.
[0030]
As shown in FIG. 9, the engine 21 includes a cylinder block 30 into which the 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. 10). Each fuel injection valve I is longer than the delivery pipe 38 that 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.
[0031]
As shown by the solid line, the delivery pipe 38 of the fuel supply device for the direct injection engine shown in FIG. 1 is connected to a high pressure passage 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 passage 40 allows the high pressure pump P2 and the delivery pipe 38 to communicate with each other. The high-pressure pump P2 is directly moved by an exhaust camshaft (not shown) on the engine body side, receives low-pressure fuel from the low-pressure pump P1 through the fuel passage 23, increases its pressure, and discharges it to the high-pressure passage 40 side.
[0032]
Here, a part of the high-pressure passage 40 branches, and a high-pressure regulator R2 and a high-pressure return passage r2 as fuel pressure adjusting means provided in parallel with the fuel injection valve I are connected thereto. The downstream end of the high pressure return passage r2 communicates with the fuel passage 23 on the upstream side of the high pressure pump P2. The high pressure regulator R2 takes in the fuel pressure (fuel pressure) of the high pressure passage 40 at the pilot port a, and receives the fuel pressure and the biasing force of the compression spring (not shown) from the opposite direction, and the fuel pressure of the high pressure passage 40 according to the balancing operation of the plunger (not shown). Is adjusted to a predetermined value, and surplus fuel passing through the high pressure regulator R2 is returned to the fuel passage 23 on the low pressure side.
[0033]
Here, the fuel passage 23 between the discharge position b of the filter 28 on the fuel tank 22 side and the suction position c on the suction port side of the high-pressure pump P2 is the longitudinal direction of the compartment 41 of the vehicle C as shown in FIG. It is longer than the length of the direction and is formed by a single pipe-like pipe. On the other hand, the length between the suction port position d (see FIG. 1) on the fuel tank 22 side and the discharge side position b of the filter 28, or the length between the suction position c and the delivery pipe 38 is the fuel passage 23. Shorter than that.
[0034]
In the engine 21 equipped with the fuel supply device 20a for the in-cylinder injection engine of FIG. 1, 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 is increased in pressure by the high-pressure pump P2 performing a predetermined pressurizing operation, and the fuel discharged from the high-pressure pump P2 passes through the high-pressure passage 40 to each fuel injection valve on the delivery pipe 38 side. When each fuel injection valve I receives a drive pulse from the ECU 39, the fuel injection valve I is opened to cause in-cylinder injection of gasoline and to generate output torque in the engine 21.
At this time, the fuel pressure in the delivery pipe 38 and the high-pressure passage 40 is regulated 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 at the downstream end of the high-pressure return passage r2. The fuel passage 23 is returned to the suction position c.
[0035]
Thus, the high-pressure fuel pressurized by the high-pressure pump P2 and heated to high temperature passes through the high-pressure regulator R2 instead of the fuel tank 22 side, reaches the suction position c of the high-pressure return passage r2, and is sucked into the high-pressure pump P2 again. It is supplied to the fuel injection valve I on the high pressure passage 40 side and consumed. For this reason, since the high-pressure fuel having a high temperature 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, and the capacity of a canister (not shown) is compared. Can be made small.
The fuel supply device 20a of the direct injection engine in FIG. 1 has its high pressure regulator R2 arranged in parallel with the fuel injection valve I. As a modified example instead of this, as shown by a two-dot chain line in FIG. You may comprise the fuel supply apparatus of the cylinder injection engine provided in the downstream of the delivery pipe 38 which equips the fuel injection valve I.
[0036]
In this case, the high pressure passage 40 extends from the downstream end side of the delivery pipe 38, the high pressure regulator R2 and the high pressure return passage r2 are sequentially connected, and the downstream end of the high pressure return passage r2 is connected to the suction position c of the fuel passage 23. The As shown by a two-dot chain line in FIG. 9, in the case of this modification, a double high-pressure passage 40 is formed in the delivery pipe 38 so that the other end forms a U-shape and communicates with the outer high-pressure passage. One end of the passage 40 communicates with the high-pressure regulator R2 side.
Also in this modified example, the high pressure regulator R2 adjusts the fuel pressure of the delivery pipe 38 and the high pressure passage 40 to a predetermined pressure, and returns the surplus fuel to the suction position c of the fuel passage 23 which is the downstream end of the high pressure return passage r2. Therefore, since the high-pressure fuel having a high temperature is not returned to the fuel tank 22, the problem that the fuel temperature in the fuel tank 22 increases and the evaporated fuel increases does not occur.
FIG. 2 shows a fuel supply device 20b for a direct injection engine as a second embodiment of the present invention.
[0037]
The in-cylinder injection engine fuel supply device 20b includes many of the same members as those in the in-cylinder injection engine fuel supply device 20a of FIG.
This in-cylinder injection engine fuel supply device 20b is provided between the low pressure pump P1 interposed in the fuel passage 23 connecting the fuel injection valve I and the fuel tank 22, and between the low pressure pump P1 and the fuel injection valve I. The high-pressure pump P2, the fuel pressure supplied to the fuel injection valve I, the high-pressure regulator R2 as a fuel pressure adjusting means provided in parallel with the fuel injection valve I so as to be adjusted to the set pressure, and the high-pressure regulator R2 The high pressure return passage r2 for returning surplus fuel to be returned to the fuel passage 23, and the fuel passage 23 between the high pressure return passage r2 and the low pressure pump P1 are connected to the fuel tank 22 via a low pressure regulator R1 as low pressure fuel adjustment means. And a low-pressure return passage r1.
[0038]
Here, the electric low-pressure pump P1 in the fuel tank 22 is sequentially connected to the check valve 27, the filter 28, the discharge side position b and the fuel passage 23 as shown in FIG.
In particular, the discharge side position b of the fuel passage 23 branches and extends through the low pressure return passage r1 where the other end opening reaches the fuel tank 22. The low pressure return passage r1 is equipped with a low pressure regulator R1 as a low pressure fuel adjusting means in the middle thereof. The low-pressure regulator R1 takes in the low-pressure fuel in the fuel passage 23 at the pilot port e, and changes the fuel pressure in the fuel passage 23 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 excess fuel discharged from the low-pressure pump P 1 is returned to the fuel tank 22.
[0039]
In the engine 21 equipped with the fuel supply device for the in-cylinder injection engine of FIG. 2, first, the electric low-pressure pump P1 discharges the low-pressure fuel to the fuel passage 23 with good response. The low-pressure fuel that has reached the fuel passage 23 is increased in pressure by the high-pressure pump P2 performing a predetermined pressurizing operation, and the fuel discharged from the high-pressure pump P2 passes through the high-pressure passage 40 to each fuel injection valve on the delivery pipe 38 side. When each fuel injection valve I receives a drive pulse from the ECU 39, the fuel injection valve I is opened to cause in-cylinder injection of gasoline and to generate output torque in the engine 21.
[0040]
In the operating range where the total amount of low pressure fuel discharged from the low pressure pump P1 and fuel from the high pressure return passage r2 is relatively larger than the suction amount of the high pressure pump P2, the low pressure fuel discharged from the low pressure pump P1, which is the surplus fuel, is used. Is returned to the fuel tank 22 through the low pressure regulator R1 and the low pressure return passage r1. As a result, the required amount of fuel is always stably supplied to the suction position c of the high-pressure pump P2. Note that the return fuel in this case is the discharge fuel of the low-pressure pump P1 and is at a relatively low temperature, and it is possible to prevent the evaporated fuel in the fuel tank 22 from increasing. On the other hand, the fuel pressure in the high-pressure passage 40 is adjusted to a predetermined pressure by the high-pressure regulator R 2, consumed by the fuel injection valve I, and surplus fuel is returned to the suction position c in the fuel passage 23.
In this way, the fuel supply device 20b for the direct injection engine as the second embodiment can always stably supply the required amount of fuel to the suction position c of the high pressure pump P2. Further, the surplus fuel in the high-pressure fuel from the high-pressure pump P2 passes through the high-pressure regulator R2 and reaches the suction position c, and is supplied to the high-pressure pump P2 and consumed again, and is not returned to the fuel tank 22. There is no problem that the fuel temperature in the tank 22 increases and the evaporated fuel increases.
[0041]
Further, the fuel passage length L1 between the discharge side position b of the fuel passage 23 which is the upstream end of the low pressure return passage r1 and the suction position c which is the downstream end of the high pressure return passage r2 is the longitudinal direction of the vehicle compartment 41. The fuel passage length L2 between the high-pressure pump P2 and the suction position c at the downstream end of the high-pressure return passage, and the fuel passage length L3 between the low-pressure pump P1 and the low-pressure return passage r1 are fuel passages. It is set to be sufficiently shorter than the length L1. Here, as compared with the case where return paths (return paths on the low pressure side and high pressure side) returning to the fuel tank side are provided in parallel with the fuel passage 23 as in a general engine fuel supply system, the low pressure here The return path r1 and the high-pressure return path r2 do not require much length. For this reason, the portion of the fuel passage 23 provided as a single pipe-like pipe is relatively large, the pipe as the whole fuel supply device is relatively short, waste can be eliminated, and cost reduction is easy to achieve.
[0042]
FIG. 3 shows a fuel supply apparatus 20c for a direct injection engine as a third embodiment of the present invention.
This in-cylinder injection engine fuel supply device 20c includes many of the same members as the in-cylinder injection engine fuel supply device 20a of FIG. 1, and here, the same reference numerals are given to the same members, and redundant description is omitted.
The in-cylinder injection engine fuel supply device 20c is provided between a low pressure pump P1 interposed in a fuel passage 23 connecting the fuel injection valve I and the fuel tank 22, and between the low pressure pump P1 and the fuel injection valve I. The high-pressure pump P2, the high-pressure regulator R2 as fuel pressure adjusting means connected downstream of the fuel injection valve I, and the high-pressure regulator R2 so that the fuel pressure supplied to the fuel injection valve I is adjusted to the set pressure. High-pressure return passage r2 for returning surplus fuel to the suction position c of the fuel passage 23, a second return passage rd branched from the high-pressure return passage r2 and connected downstream to the fuel tank 22 side, and a high-pressure return passage r2 There is provided switching valve means 42 for switching so as to guide the surplus fuel to either the suction position c at the downstream end or the second return passage rd.
[0043]
The fuel passage 23 includes a low pressure return passage r1 that connects the discharge side position b of the filter 28 to the fuel tank 22 via the low pressure regulator R1.
An electromagnetic actuator (not shown) of the switching valve means 42 is connected to an ECU 39c (which has the same configuration as that of the ECU 39a in FIG. 1 except that only the control program is partially different). In the normal operation state, a function of switching and controlling the surplus fuel upstream of the low-pressure pump and leading to the second return passage rd at the start of the specific operation state is provided. The specific operation state is set to an operation region before the start is completed (an operation region equal to or lower than a predetermined cranking speed), and is set to an operation region where the discharge pressure of the high-pressure pump P2 is not sufficient.
For this reason, the discharge pressure of the high-pressure pump P2 is low before the start is completed. Even in this case, the discharge pressure of the electric low-pressure pump P1 is added to the fuel injection valve I through the high-pressure pump P2 with good responsiveness. Is possible.
[0044]
Assume that the engine 21 equipped with the fuel supply device for the in-cylinder injection engine of FIG. 3 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 pump P2 at the beginning of the start and is added to the fuel injection valve I. Thereafter, the low-pressure fuel is increased in pressure by the pressurization operation of the high-pressure pump P2 as the engine speed increases. And is supplied to each fuel injection valve I on the delivery pipe 38 side via the high-pressure passage 40, and is opened when each fuel injection valve I receives a drive pulse of the ECU 39c, to execute in-cylinder injection of gasoline, An output torque is generated in the engine 21.
[0045]
At the time of starting, the high pressure pump P2 starts driving. At this time, the switching valve means 42 downstream of the high pressure regulator R2 switches to the second switching position s2 in accordance with the ON signal output at the time of starting from the ECU 39c. Be Thereafter, when the surplus fuel passes through the high pressure regulator r2 in the normal operation state, the bubbles staying in the delivery pipe 38 and the high pressure return passage r2 are returned to the fuel tank 22 from the second return passage rd to remove the bubbles. Can be done. Note that after completion of the normal operation for a predetermined time, the ECU 39c outputs an OFF signal to the switching valve means 42, and switches the switching valve means 42 to the first switching position s1.
The switching valve means 42 determines whether there is no problem even if the excess fuel is returned to the fuel tank based on the detection means for detecting the fuel temperature or the like in the fuel tank 22 or the engine operating state detection means. If there is no problem, it may be controlled to switch to the second switching position s2, and if there is a problem, control may be performed to switch to the first switching position s1.
[0046]
In normal operation after completion of the start-up, in the operating region where the total amount of low-pressure fuel discharged from the low-pressure pump P1 and fuel from the high-pressure return passage r2 is relatively large relative to the suction amount of the high-pressure pump P2, the surplus fuel is The fuel is returned to the fuel tank 22 via the low pressure regulator R1, and the required amount of fuel is always stably supplied to the suction position c of the high pressure pump P2. Note that the return fuel in this case is the discharge fuel of the low-pressure pump P1 and is at a relatively low temperature, and it is possible to prevent the evaporated fuel in the fuel tank 22 from increasing.
[0047]
On the other hand, the fuel pressure in the high-pressure passage 40 is adjusted to a predetermined pressure by the high-pressure regulator R2, consumed by the fuel injection valve I, and the surplus fuel passes through the switching valve means 42 in the first switching position s1 and the suction position c in the fuel passage 23. Returned to For this reason, the required amount of fuel can always be stably supplied to the suction position c of the high-pressure pump P2, and excess fuel is not returned to the fuel tank 22, so that the fuel temperature in the fuel tank 22 increases and the evaporated fuel increases. Does not cause the problem of
Note that the second return passage rd communicated when the switching valve means 42 is switched to the second switching position s2 is directly returned to the fuel tank 22 in FIG. 3, but instead of this, FIG. As indicated by a two-dot chain line, the downstream end of the second return passage rd may be connected to the low pressure return passage r1 between the low pressure regulator R1 and the discharge side position b.
[0048]
FIG. 4 shows a fuel supply device 20d for a direct injection engine as a fourth embodiment of the present invention.
This in-cylinder injection engine fuel supply device 20d includes many of the same members as the in-cylinder injection engine fuel supply device 20c of FIG.
[0049]
The in-cylinder injection engine fuel supply device 20c is provided between a low pressure pump P1 interposed in a fuel passage 23 connecting the fuel injection valve I and the fuel tank 22, and between the low pressure pump P1 and the fuel injection valve I. The high-pressure pump P2, the high-pressure regulator R2 as fuel pressure adjusting means connected downstream of the fuel injection valve I, and the high-pressure regulator R2 so that the fuel pressure supplied to the fuel injection valve I is adjusted to the set pressure. A high pressure return passage r2 for returning surplus fuel to be returned to the suction position c of the fuel passage 23, a second return passage rd branched from the high pressure return passage r2 and connected downstream to the fuel tank 22 side, and a high pressure return passage r2 A switching valve means 42 for switching so as to guide surplus fuel to either the suction position c at the downstream end or the second return passage rd, and a high pressure regulator Comprises a bypass passage rb for connecting the upstream side and the downstream side fuel passage 23 parts of 2, the opening and closing valve 43 for opening and closing the bypass passage rb. An orifice OS is provided in the bypass passage rb.
[0050]
Each electromagnetic actuator (not shown) of the switching valve means 42 and the on-off valve 43 is connected to an ECU 39d as a control means, and the ECU 39d particularly in the switching control of the switching valve means 42 performs a normal operation other than when the internal combustion engine is started. In the state, the surplus fuel is switched to the upstream of the high-pressure pump P2 so as to be led to the second return passage rd at the time of starting as the specific operating state, and in the switching control of the on-off valve 43, it is turned off in the normal operating state other than the starting time of the internal combustion engine. Then, the valve is operated to the valve closing position q1 and is turned on at the time of starting as the specific operation state to operate to the valve opening position q2.
The specific operation state is set to an operation region before the start is completed (an operation region equal to or lower than a predetermined cranking speed), and is set to an operation region where the discharge pressure of the high-pressure pump P2 is not sufficient.
[0051]
For this reason, the discharge pressure of the high-pressure pump P2 is low before the start is completed. Even in this case, the discharge pressure of the electric low-pressure pump P1 is added to the fuel injection valve I through the high-pressure pump P2 with good responsiveness. Is possible.
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 P 1 discharges the low-pressure fuel into the fuel passage 23. The low-pressure fuel that has reached the fuel passage 23 passes through the high-pressure pump P2 in the initial stage of startup and is added to the fuel injection valve I.
[0052]
At the time of starting, the high-pressure pump P2 starts driving. At this time, the switching valve means 42 downstream of the high-pressure regulator R2 and the opening / closing valve 43 of the bypass passage rb are in response to an ON signal output at the time of starting from the ECU 39. The position is switched to the second switching position s2 and the valve opening position q2. For this reason, the bubbles staying in the delivery pipe 38 and the high pressure return passage r2 are returned to the fuel tank 22 from the bypass passage rb, the high pressure return passage r2 and the second return passage rd at the time of starting, and the bubbles can be removed. Can be improved. In addition, the high pressure regulator R2 can be bypassed at the time of starting, air bubbles can be reliably removed, the fuel flow at the time of starting can be promoted, and the startability is improved. Further, the fuel pressure in the fuel injection valve I is set to a pressure slightly lower than the fuel pressure set by the low pressure regulator R1 due to the presence of the orifice OS, so that the fuel supply amount at the start can be adjusted accurately.
[0053]
After completion of the start-up, the ECU 39d can output an OFF signal to the switching valve means 42 and the on-off valve 43, respectively, switch the switching valve means 42 to the first switching position s1, and switch the on-off valve 43 to the valve closing position q1. At this time, the low-pressure fuel that has reached the high-pressure pump is increased in pressure by the pressurizing operation of the high-pressure pump P2, and is supplied to each fuel injection valve I on the delivery pipe 38 side through the high-pressure passage 40, and each fuel injection valve I is connected to the ECU 39d. 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.
[0054]
The fuel supply device 20d for the in-cylinder injection engine of the fourth embodiment can achieve the same effects as the fuel supply device 20c for the in-cylinder injection engine of the third embodiment, and the opening / closing valve 43 is particularly open at the time of starting. Since the valve position q2 is switched, the bubbles staying in the delivery pipe 38 and the high-pressure return passage r2 are bypassed the high-pressure regulator R2 to the fuel tank 22 through the bypass passage rb, the high-pressure return passage r2, and the second return passage rd. Since it can be returned, it is possible to surely remove bubbles, promote the flow of fuel at the start, and improve the startability.
FIG. 5 shows a fuel supply device 20e for a direct injection engine as a fifth embodiment of the present invention.
The fuel supply device 20e for the in-cylinder injection engine includes many of the same members as those of the fuel supply device 20a for the in-cylinder injection engine of FIG.
[0055]
This in-cylinder injection engine fuel supply device 20e is provided between the low pressure pump P1 interposed in the fuel passage 23 connecting the fuel injection valve I and the fuel tank 22, and between the low pressure pump P1 and the fuel injection valve I. The high-pressure pump P2, the fuel pressure supplied to the fuel injection valve I, the high-pressure regulator R2 as a fuel pressure adjusting means provided in parallel with the fuel injection valve I so as to be adjusted to the set pressure, and the high-pressure regulator R2 A high-pressure return passage r2 for returning surplus fuel to be returned to the fuel passage 23 between the high-pressure pump P2 and the low-pressure pump P1, and a second fuel passage upstream and downstream of the high-pressure pump P2 so as not to pass through the high-pressure regulator R2. And a bypass passage rb2.
[0056]
Here, the second bypass passage rb2 functions as an inherent squeezing for the fuel passing through the flow path, and in particular, has a flow resistance to such an extent that the discharge pressure of the high-pressure pump P2 can be secured at a predetermined value during normal operation. It is formed so that it can be generated. That is, it is set so that a differential pressure is generated between the upstream side and the downstream side of the high-pressure regulator R2. In addition, when the flow rate is low at the beginning of startup, the fuel discharged from the low pressure pump P1 can be guided to the fuel injection valve I on the delivery pipe 38 side through the fuel passage 23, the second bypass passage rb2, and the high pressure passage 40.
[0057]
In the engine 21 equipped with the fuel supply device for the in-cylinder injection engine of FIG. 5, 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, passes through the second bypass passage rb2 and the high-pressure passage 40, and reaches the fuel injection valve I on the delivery pipe 38 side. When the engine is received, the engine is opened to cause in-cylinder injection of gasoline to be executed, and the engine 21 generates output torque.
After this start-up operation, during normal operation, the low-pressure fuel discharged from the low-pressure pump P1 is supplied to the suction position c of the high-pressure pump P2, and the required amount of fuel is always supplied stably. The fuel discharged from the high pressure pump P2 during this normal operation acts as a squeeze for the fuel flowing into the second bypass passage rb2, and generates a higher fuel pressure in the high pressure passage 40 than on the fuel passage 23 side. Moreover, the fuel pressure generated here is regulated to a predetermined pressure in the high-pressure passage 40 by the high-pressure regulator R2.
[0058]
The fuel in the high pressure passage 40 is consumed by the fuel injection valve I, and the surplus fuel is returned to the suction position c of the fuel passage 23 through the second bypass passage rb2 and the high pressure regulator R2.
Thus, the fuel supply device 20e of the direct injection engine as the fifth embodiment can always stably supply the required amount of fuel to the suction position c of the high pressure pump P2. Further, surplus fuel in the high-pressure fuel from the high-pressure pump P2 passes through the second bypass passage rb2 and the high-pressure regulator R2, is returned to the suction position c, is supplied again to the high-pressure pump P2, is consumed, and 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.
[0059]
FIG. 6 shows a fuel supply apparatus 20f for a direct injection engine as a sixth embodiment of the present invention.
The in-cylinder injection engine fuel supply device 20f includes many of the same members as the in-cylinder injection engine fuel supply device 20e of FIG. 5, and the same members are denoted by the same reference numerals and redundant description is omitted.
[0060]
This in-cylinder injection engine fuel supply device 20f is provided between the low pressure pump P1 interposed in the fuel passage 23 connecting the fuel injection valve I and the fuel tank 22, and between the low pressure pump P1 and the fuel injection valve I. The high-pressure pump P2, the fuel pressure supplied to the fuel injection valve I, the high-pressure regulator R2 as a fuel pressure adjusting means provided in parallel with the fuel injection valve I so as to be adjusted to the set pressure, and the high-pressure regulator R2 A high-pressure return passage r2 for returning surplus fuel to be returned to the fuel passage 23 between the high-pressure pump P2 and the low-pressure pump P1, and a second fuel passage upstream and downstream of the high-pressure pump P2 so as not to pass through the high-pressure regulator R2. A bypass passage rb2 and a second on-off valve 44 provided in the second bypass passage rb2 are provided.
[0061]
Here, the second on-off valve 44 of the second bypass passage rb2 is connected to an ECU 39f (not shown) having an electromagnetic actuator (not shown) having the same configuration as the ECU 39c in FIG. It is held at the valve closing position u1 according to the off signal output at the time, and is switched and held at the valve opening position u2 according to the on signal output at the start.
In particular, in the switching control of the second on-off valve 44, the ECU 39f has a function of switching to the valve closing position u1 in a normal operation state other than at the time of starting the internal combustion engine, and switching to the valve opening position u2 at the time of starting as a specific operation state. The specific operation state is set to an operation region before the start is completed (an operation region equal to or lower than a predetermined cranking speed), and is set to an operation region where the discharge pressure of the high-pressure pump P2 is not sufficient.
[0062]
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). At the time of starting, the ECU 39f outputs an ON signal to the second on-off valve 44. At this time, 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, passes through the second bypass passage rb2 and the high-pressure passage 40, reaches the fuel injection valve I on the delivery pipe 38 side, and each fuel injection valve I is connected to the ECU 39f. When the drive pulse is received, the opening operation is performed, the gasoline is injected into the cylinder, and the engine 21 generates an output torque.
Immediately after the start, when the engine speed increases, the high-pressure pump P2 starts driving. At this time, the ECU 39f outputs an OFF output to the second on-off valve 44, and in the subsequent normal operation state, the first position is at the valve closing position u1. 2 The on-off valve 44 is held.
[0063]
As described above, the fuel supply device 20f for the direct injection engine according to the sixth embodiment can prevent the high pressure pump P2 that is not discharging at the time of start-up from acting as a squeeze, and the low pressure bypassing the second bypass passage rb2. The low-pressure fuel of the pump P1 can be directly guided to the fuel injection valve I on the delivery pipe 38 side, and startability can be improved.
On the other hand, in the normal operation state, the second bypass passage rb2 is closed, and the high pressure regulator R2 adjusts the fuel pressure on the high pressure return passage r2 side to return surplus fuel to the suction position c, thereby enabling high pressure injection and the suction position c. Can always supply the required amount of fuel stably. Further, the surplus fuel in the high-pressure fuel from the high-pressure pump P2 is returned to the suction position c, supplied to the high-pressure pump P2 and consumed again, and is not returned to the fuel tank 22. Therefore, the fuel temperature in the fuel tank 22 This raises the problem of increasing the amount of evaporated fuel.
[0064]
FIG. 7 shows a fuel supply device 20j for a direct injection engine as a seventh embodiment of the present invention.
The fuel supply device 20j for this direct injection engine has many identical components except that a check valve 45 is provided instead of the second on-off valve 44 in the fuel supply device 20e for the direct injection engine shown in FIG. Here, the same members are denoted by the same reference numerals, and redundant description is omitted.
The second bypass passage rb2 of the fuel supply device 20j of the direct injection engine is equipped with a check valve 45 that allows only the flow from the fuel passage 23 toward the high pressure passage 40. This check valve 45 can flow the low-pressure fuel of the low-pressure pump P1 to the high-pressure passage 40 by bypassing the high-pressure pump P2 from the fuel passage 23, and the flow of the high-pressure fuel in the high-pressure passage 40 to the fuel passage 23 at the normal time. Stop.
[0065]
Assume that the engine 21 equipped with the fuel supply device 20j for the in-cylinder injection engine of FIG. 7 is started by turning on a key switch (not shown). At the time of starting, 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, passes through the check valve 45, the second bypass passage rb2, and the high-pressure passage 40 and reaches the fuel injection valve I on the delivery pipe 38 side. Is opened when the ECU 39f receives a driving pulse, and in-cylinder injection of gasoline is executed to cause the engine 21 to generate output torque.
[0066]
Immediately after the start, when the engine speed increases, the high pressure pump P2 starts to be driven. At this time, the check valve 45 prevents the flow of the high pressure fuel into the fuel passage 23 as the fuel pressure in the high pressure oil passage 40 increases. The fuel pressure in the high-pressure oil passage 40 is adjusted by the high-pressure regulator R2, and the surplus fuel is returned to the suction position c through the high-pressure return passage r2.
[0067]
As described above, the fuel supply device 20j for the direct injection engine according to the seventh embodiment can prevent the high pressure pump P2 that is not discharged at the time of start-up from acting as a squeeze, and the low pressure bypassing the second bypass passage rb2. The low-pressure fuel of the pump P1 can be directly guided to the fuel injection valve I on the delivery pipe 38 side, and startability can be improved.
On the other hand, in the normal operation state, the check valve 45 closes the second bypass passage rb2, guides the low pressure fuel from the low pressure pump P1 to the fuel injection valve I through the high pressure pump P2, and the high pressure regulator R2 is connected to the high pressure return passage r2 side. Since the fuel pressure is adjusted and the surplus fuel is returned to the suction position c, stable high-pressure injection can be performed and a necessary amount of fuel can always be supplied to the suction position c. Furthermore, since the surplus fuel in the high-pressure fuel from the high-pressure pump P2 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.
[0068]
In the above description, when the flow resistance of the high-pressure pump P2 is large and a sufficient fuel pressure cannot be generated for the fuel injection valve in a specific operation state such as at the time of starting, the seventh implementation is performed. It is preferable to provide the check valve 45 and the second bypass passage rb2 as shown in the examples also for the second to fourth embodiments.
Note that the high pressure regulator R2 in the seventh embodiment may be provided on the downstream side of the delivery pipe 38, as indicated by the two-dot chain line in the first embodiment.
FIG. 8 shows a fuel supply device 20h for a direct injection engine as an eighth embodiment of the present invention.
[0069]
The in-cylinder injection engine fuel supply device 20h is identical to the in-cylinder injection engine fuel supply device 20f of FIG. 6 except that a low-pressure return passage r1 is provided upstream of the fuel passage 23. In many cases, the same members are denoted by the same reference numerals, and redundant description is omitted.
Here, the discharge side position b of the fuel passage 23 branches and extends through the low-pressure return passage r <b> 1 whose other end opening reaches the fuel tank 22. The low pressure return passage r1 is equipped with a low pressure regulator R1 as a low pressure fuel adjusting means in the middle thereof. The low-pressure regulator R1 takes in the low-pressure fuel in the fuel passage 23 at the pilot port e, and determines the hydraulic pressure in the low-pressure return passage r1 in accordance with the balance operation of the plunger (not shown) that receives the fuel pressure and the urging force of the compression spring (not shown) from the opposite direction. The pressure is adjusted to the value, and the surplus fuel discharged from the low pressure pump P1 is returned to the fuel tank 22.
[0070]
The second bypass passage rb2 is provided with a switching valve means 44, which closes in response to an OFF signal that is normally output from the ECU 39h (which has the same configuration as the ECU 39f in FIG. 6 except that only the control program is partially different). The valve position is held at the valve position u1, and is switched and held at the valve opening position u2 in accordance with an ON signal output at the time of starting.
An ECU 39h is connected to an electromagnetic actuator (not shown) of the switching valve means 44, and the ECU 39h exhibits the same control function as the ECU 39f.
[0071]
It is assumed that the engine 21 equipped with the fuel supply device 20h for the in-cylinder injection engine of FIG. 8 is started by turning on a key switch (not shown). At the time of starting, the ECU 39h outputs an ON signal to the second on-off valve 44. At this time, 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, passes through the second bypass passage rb2 and the high-pressure passage 40, reaches the fuel injection valve I on the delivery pipe 38 side, and each fuel injection valve I drives the drive pulse of the ECU 39f. When the engine is received, the engine is opened to cause in-cylinder injection of gasoline to be executed, and the engine 21 generates output torque.
[0072]
Immediately after the start, when the engine speed increases, the high pressure pump P2 starts to be driven. At this time, the second on-off valve 44 of the high pressure passage 40 is switched and held at the valve closing position u1 by the ECU 39h. The flow to the passage 23 is blocked, the hydraulic pressure in the high pressure oil passage 40 is regulated by the high pressure regulator R2, and the surplus fuel is returned to the suction position c.
[0073]
During normal operation after the start-up operation, the surplus fuel in the operating range where the total amount of low-pressure fuel discharged from the low-pressure pump P1 and fuel from the high-pressure return passage r2 is relatively larger than the suction amount of the high-pressure pump P2. The low pressure fuel discharged from the low pressure pump P1 is returned to the fuel tank 22 via the low pressure regulator R1 and the low pressure return passage r1. As a result, the required amount of fuel is always stably supplied to the suction position c of the high-pressure pump P2. Note that the return fuel in this case is the discharge fuel of the low-pressure pump P1 and is at a relatively low temperature, and it is possible to prevent the evaporated fuel in the fuel tank 22 from increasing.
[0074]
On the other hand, after the second on-off valve 44 is held at the valve closing position u1, the fuel pressure in the high pressure passage 40 is regulated to a predetermined pressure by the high pressure regulator R2, consumed by the fuel injection valve I, and surplus fuel is consumed in the fuel passage 23. Is returned to the suction position c.
In this way, the fuel supply device 20h for the direct injection engine as the eighth embodiment can always stably supply the required amount of fuel to the suction position c of the high-pressure pump P2. Further, since the surplus fuel from the high pressure pump P2 is supplied again to the high pressure pump P2 from the suction position c and is consumed, it is not returned to the fuel tank 22, so that the fuel temperature in the fuel tank 22 increases and the evaporated fuel Does not cause the problem of increase.
[0075]
Further, the fuel passage length L1 ′ between the discharge side position b of the fuel passage 23 that is the upstream end of the low pressure return passage r1 and the suction position c that is the downstream end of the high pressure return passage r2 is the vehicle interior 41 (FIG. 10). The fuel passage length L2 ′ between the high pressure pump P2 and the suction position c at the downstream end of the high pressure return passage and the fuel passage length between the low pressure pump P1 and the low pressure return passage r1. It is set sufficiently longer than the length L3 ′. That is, as shown in FIG. 10, the fuel passage length L2 ′ is longer than the length in the longitudinal direction of the passenger compartment 41, but this portion is formed as a single pipe-like pipe, and this part is formed by a plurality of pipes. Compared to the case, the use of a single pipe eliminates the waste of the pipe and facilitates cost reduction.
[0076]
FIG. 11 shows a fuel supply device 20i for a diesel engine as a ninth embodiment of the present invention.
As shown in FIG. 11, the fuel supply device 20 i is provided with a low-pressure pump P <b> 1 in the fuel tank 22 that pressurizes the fuel in the fuel tank 22 and supplies it to the fuel injection valve I side. Further, a check valve 27 and a filter 28 are sequentially interposed in the fuel passage 23 between the low pressure pump P1 and the fuel injection valve I, and a distribution type for supplying high pressure fuel to each fuel injection valve I. Is provided with a high-pressure fuel injection pump P2. In this embodiment, the distribution-type high-pressure fuel injection pump P2 is provided, but a row-type high-pressure fuel injection pump may be used. Further, a high-pressure return passage r2 is provided in which surplus fuel generated after fuel injection of each fuel injection valve I is connected to the suction position c on the upstream side of the high-pressure fuel injection pump P2.
[0077]
Next, the fuel injection valve I here will be described. As shown in FIG. 12, the fuel injection valve I has an injection hole 51 formed at the tip of a holder body 50, and a slidable needle 53 provided therein. The needle 53 is urged toward the nozzle hole 51 by a spring member (spring) 52 of a spring chamber formed on the side opposite to the nozzle hole 51. The needle 53 communicates with the high-pressure fuel injection pump P2 and is connected to an oil reservoir 54 formed between the needle 53 and the holder body 50 via a fuel passage 55 formed in the holder body 50. When the high-pressure fuel metered in P2 is applied, it is configured to move upward against the urging force of the spring member 52 to open the injection hole 51 and inject fuel into a combustion chamber (not shown). Yes.
[0078]
When the high-pressure fuel from the high-pressure fuel injection pump P2 is not applied, the injection is finished, and the needle 53 returns to the original state in which the injection hole 51 is closed. In this case, surplus fuel flows to the spring chamber side through the gap between the holder body 50 and the needle 53. In order to prevent the surplus fuel from increasing the internal pressure in the spring chamber and suppressing the operation of the needle 53, An escape passage 56 for allowing the surplus fuel to escape is formed inside the adjusting screw 57. The escape passage 56 is connected to the high pressure return passage r2.
[0079]
As described above, also in the fuel supply device 20i for the diesel engine of the ninth embodiment, the surplus fuel that has been increased in pressure and increased in temperature by the high-pressure fuel injection pump P2 can be returned to the fuel tank 22 in the same manner as each of the embodiments described above. Therefore, it is possible to prevent the fuel in the fuel tank 22 from increasing in temperature and evaporating fuel from increasing. Further, since the high pressure return passage r2 is not returned to the fuel tank 22, it is advantageous in terms of piping, and there is an effect that the cost can be reduced.
[0080]
In the above description, the present invention is not limited to the above embodiments, and the engine 21 is mounted on the fuel supply system of a four-cylinder DOHC gasoline engine. Alternatively, it can be mounted on a multi-cylinder engine using alcohol fuel other than gasoline. In the present invention, the high-pressure pump is an engine drive type, but may be a motor drive type. Further, each of the above embodiments relates to an in-cylinder injection type engine in which a fuel injection valve directly faces the combustion chamber. However, the present invention is also applicable to an intake port injection type engine.
[0081]
【The invention's effect】
  As described above, according to the first aspect of the present invention, the fuel in the fuel tank is sequentially pressurized by the low pressure pump and the high pressure pump, and the high pressure fuel is injected by the fuel pressure adjusting means provided downstream of the delivery pipe. Since the fuel pressure supplied to the valve is adjusted to the set pressure, and in particular, a high pressure return passage is provided for returning surplus fuel passing through the fuel pressure adjusting means to the fuel passage between the high pressure pump and the low pressure pump. You can regulate the return to the tank.
For this reason, generation of evaporated fuel in the fuel tank can be reduced. In particular, a second return passage branched from the high pressure return passage and connected downstream to the fuel tank side is disposed, and switching is performed so as to guide surplus fuel to either the downstream end of the high pressure return passage or the second return passage. Since the valve means is provided, surplus fuel after passing through the fuel pressure adjusting means is selectively guided to the downstream end of the high-pressure return passage and the fuel tank side in accordance with the switching of the switching valve means. For this reason, generation | occurrence | production of evaporative fuel in a fuel tank can be reduced, and surplus fuel can be returned to a fuel tank as needed, such as bubble removal.
[0086]
  Claim2The invention of claim1In the fuel supply device for an internal combustion engine described above, in particular, the switching valve means is controlled by the control means, and surplus fuel is guided upstream of the high-pressure pump in the normal operation state of the internal combustion engine and to the second return passage in the specific operation state. In accordance with the normal operation state and the specific operation state, surplus fuel after passing through the fuel pressure adjusting means is selectively guided to the downstream end of the high-pressure return passage and the fuel tank side.
  For this reason, generation | occurrence | production of evaporative fuel in a fuel tank can be reduced in a normal operation state, and surplus fuel can be returned to a fuel tank as needed, such as bubble extraction, in a specific operation state.
[0087]
  Claim3The invention of claim1In the fuel supply device for an internal combustion engine described above, the fuel passage portions on the upstream side and the downstream side of the fuel pressure adjusting means are connected by the bypass passage provided with the on-off valve, so that the bypass passage can be opened and closed as necessary.
  For this reason, a bypass channel can be opened and closed according to an engine operating state, and the characteristic of a fuel supply system can be improved.
[0088]
  Claim4The invention of claim3In the internal combustion engine fuel supply apparatus described above, the on-off valve is controlled by the control means, and the on-off valve is closed in the normal operation state of the internal combustion engine and opened in the specific operation state. Therefore, the bypass passage is specified as the normal operation state. It can be opened and closed as needed depending on the driving state.
  For this reason, the bypass passage can be opened in the specific operation state to improve air bleeding and startability.
[0089]
  Claim5The invention of claim2Or claim4In the fuel supply device for an internal combustion engine described above, the specific operation state is set, in particular, a state in which the discharge pressure of the high-pressure pump is not sufficient.
  For this reason, even when the discharge pressure of the high pressure pump is not sufficient, the excess fuel after passing through the fuel pressure adjusting means is returned to the fuel tank side by the second return passage, or the bypass pressure is opened to bypass the fuel pressure adjusting means. Can be improved.
[0090]
  Claim6The invention of claim5In the fuel supply device for an internal combustion engine described above, in particular, since the high pressure pump is driven by the internal combustion engine and the specific operation state is when the internal combustion engine is started, the high pressure pump can be driven when the internal combustion engine is driven. The surplus fuel after passing through the fuel pressure adjusting means can be returned to the fuel tank side by the second return passage.
  For this reason, at the time of start-up, the bypass passage can be opened to bypass the fuel pressure adjusting means, thereby removing air bubbles.
[0097]
  Claim7The invention of claim1In the fuel supply apparatus for an internal combustion engine described above, the low pressure return passage for returning the fuel upstream of the high pressure pump to the fuel tank is disposed via the low pressure fuel adjusting means, so that a relatively large amount of surplus fuel with respect to the suction amount of the high pressure pump Even in certain operating areas, excess fuel is returned to the high pressure pump again,ofExcess fuel in the discharged low-pressure fuel is returned to the fuel tank.
  For this reason, the high pressure pumpofSuction positionInAlways supplies the required amount of fuel stably, can regulate the temperature rise in the fuel tank, and can reduce the generation of evaporated fuel.
[0098]
  Claim8The invention of claim7In the fuel supply device for an internal combustion engine described above, the upstream side of the low pressure return passage is located downstream of the high pressure return passage and upstream of the upstream end of the second bypass passage. It becomes easy to secure a relatively long distance between the side and the second bypass passage with a single pipe.
  For this reason, the portion of the single pipe becomes longer, the high-pressure return passage, the second bypass passage, and the low-pressure return passage can be set short, and the cost can be reduced by simplifying the piping.
[0099]
  Claim9The invention of claim8In the fuel supply device for an internal combustion engine described above, the upstream side of the low pressure return passage is provided close to the low pressure pump, and the downstream end of the high pressure return passage and the upstream end of the second bypass passage are provided close to the high pressure pump. Therefore, it is easy to ensure a relatively long distance between the upstream side of the low pressure return passage and the downstream end side of the high pressure return passage.
  For this reason, the portion of the single pipe becomes longer, and the high-pressure return passage, the second bypass passage, and the low-pressure return passage can be set to be short, and the cost can be reduced by simplifying the piping.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a fuel supply device for a direct injection engine according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a fuel supply device for a direct injection engine according to a second embodiment of the present invention.
FIG. 3 is a schematic configuration diagram of a fuel supply device for a direct injection engine according to a third embodiment of the present invention.
FIG. 4 is a schematic configuration diagram of a fuel supply device for a direct injection engine according to a fourth embodiment of the present invention.
FIG. 5 is a schematic configuration diagram of a fuel supply device for a direct injection engine according to a fifth embodiment of the present invention.
FIG. 6 is a schematic configuration diagram of a fuel supply device for a direct injection engine according to a sixth embodiment of the present invention.
FIG. 7 is a schematic configuration diagram of a fuel supply device for a direct injection engine as a seventh embodiment of the present invention.
FIG. 8 is a schematic configuration diagram of a fuel supply device for a direct injection engine according to an eighth embodiment of the present invention.
FIG. 9 is a longitudinal sectional view of a direct injection engine as a first embodiment of the present invention.
FIG. 10 is a schematic layout view of a vehicle equipped with an in-cylinder injection engine as a first embodiment of the present invention.
FIG. 11 is a schematic configuration diagram of a fuel supply device for a diesel engine as a ninth embodiment of the present invention.
12 is a cross-sectional view of a fuel injection valve used by the fuel supply device of FIG.
FIG. 13 is a schematic configuration diagram of a conventional fuel supply device for a direct injection engine.
[Explanation of symbols]
20a-20i Fuel supply device for in-cylinder injection engine
21 engine
22 Fuel tank
23 Fuel passage
28 Filter
38 Delivery pipe
39a, 39c, 39d, 39f, 39h
ECU
40 High pressure passage
a Pilot port
c Suction position
b Discharge side position
e Pilot port
rb bypass passage
rb2 second bypass passage
rd second return passage
r1 Low pressure return passage
r2 High pressure return passage
I Fuel injection valve
P1 Low pressure pump
P2 high pressure pump
R1 Low pressure regulator
R2 high pressure regulator

Claims (9)

A low pressure pump interposed in a fuel passage connecting the fuel injection valve and the fuel tank;
A high-pressure pump provided between the low-pressure pump and the fuel injection valve;
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;
Fuel pressure adjusting means provided downstream of the delivery pipe so that the fuel pressure supplied to the fuel injection valve is adjusted to a set pressure;
The surplus fuel passing through the fuel pressure adjusting means possess a high pressure return passage to return to the fuel passage between the high pressure pump and the low-pressure pump,
A second return passage branched from the high pressure return passage and connected downstream to the fuel tank is disposed;
A fuel supply device for an internal combustion engine, characterized in that switching valve means for switching the surplus fuel to guide either the downstream end of the high-pressure return passage or the second return passage is provided. The fuel supply device for an internal combustion engine according to claim 1 ,
The switching valve means includes a control means for controlling the surplus fuel to be switched upstream of the high-pressure pump in a normal operation state of the internal combustion engine and to a second return passage in a specific operation state. apparatus. The fuel supply device for an internal combustion engine according to claim 1 ,
A bypass passage connecting the upstream and downstream fuel passage portions of the fuel pressure adjusting means is disposed;
An on-off valve for opening and closing the bypass passage is provided. The fuel supply device for an internal combustion engine according to claim 3 ,
The fuel supply device for an internal combustion engine, characterized in that the open / close valve includes a control means for performing open / close control so that the open / close valve is closed in a normal operation state and opened in a specific operation state . The fuel supply device for an internal combustion engine according to claim 2 or 4,
The fuel supply device for an internal combustion engine , wherein the specific operation state is a state where the discharge pressure of the high-pressure pump is not sufficient . The fuel supply device for an internal combustion engine according to claim 5 ,
A fuel supply device for an internal combustion engine, wherein the high-pressure pump is driven by the internal combustion engine, and the specific operation state is when the internal combustion engine is started . The fuel supply device for an internal combustion engine according to claim 1,
A fuel supply apparatus for an internal combustion engine, characterized in that a low-pressure return passage is provided for returning fuel upstream of the high-pressure pump to the fuel tank via low-pressure fuel adjusting means. The fuel supply device for an internal combustion engine according to claim 7,
A second bypass passage having an on-off valve connected to the upstream and downstream fuel passages of the high-pressure pump is disposed so as not to pass through the fuel pressure adjusting means, and the upstream side of the low-pressure return passage is downstream of the high-pressure return passage. And a fuel supply device for an internal combustion engine, which is located upstream of the upstream end of the second bypass passage. The fuel supply device for an internal combustion engine according to claim 8,
An internal combustion engine characterized in that an upstream side of the low pressure return passage is provided close to the low pressure pump, and a downstream end of the high pressure return passage and an upstream end of the second bypass passage are provided close to the high pressure pump . Fuel supply device.

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