JP4589039B2 - Fuel supply device for internal combustion engine - Google Patents

Description

  The present invention relates to a fuel supply device for an internal combustion engine that pumps up fuel in a fuel tank by a low-pressure pump (feed pump), boosts the fuel to a required pressure (fuel pressure) by a high-pressure pump, and sends the pressure to a fuel injection valve. Is.

  In a diesel engine that directly injects fuel into a cylinder, it is necessary to increase the injection pressure in order to atomize the injected fuel. Therefore, in a general fuel supply apparatus driven by a diesel engine, a low-pressure pump (feed pump), a suction metering valve, and a high-pressure pump are arranged in series in the fuel flow path connecting the fuel tank and the fuel injection valve. Configuration is adopted. In this fuel supply device, fuel in the fuel tank is pumped up by a feed pump (low pressure pump), metered to a predetermined amount by a suction metering valve, and sent to a high pressure pump. In the high-pressure pump, the metered fuel sucked in as described above is boosted to a required pressure (fuel pressure) and discharged. The discharged high-pressure fuel is pumped to the fuel injection valve via a high-pressure fuel pipe (common rail).

  By the way, the fuel amount per unit time necessary for the operation of the diesel engine (more precisely, the maximum value) is the engine speed except for the extremely low speed range at the time of engine start, as indicated by the characteristic line L1 in FIG. Increase with the rise of. In the extremely low rotational speed range at the time of engine start, the amount of fuel required increases for the purpose of ensuring ignitability.

  On the other hand, the discharge amount per unit time of the fuel supply device is originally small (when calculated) when the rotational speed is low, and increases proportionally with the increase in rotational speed, as indicated by the characteristic line L2. However, in actuality, not a small amount of fuel leaks from the movable part. Therefore, the characteristic of the discharge amount with respect to the rotational speed becomes smaller than the calculated value as shown by the characteristic line L3, and the difference between the two (volume efficiency) Decrease) occurs. This decrease in volumetric efficiency increases as the rotational speed decreases. This is because the lower the rotation speed, the longer the fuel leakage time.

  Therefore, in order to secure the required fuel amount in the entire rotational speed range from the extremely low rotational speed range to the high rotational speed range at the time of starting the engine, usually, the extremely low rotational speed at which the fuel discharge amount in the fuel supply device is minimized. The discharge characteristic of the fuel supply device is set based on the speed range. That is, the discharge characteristic of the fuel supply device is set so that a slightly larger amount of fuel than the required fuel amount is discharged in the extremely low rotational speed range (see characteristic line L3).

In addition, as a prior art document concerning this invention, the following patent documents 1 are mentioned, for example.
JP-A-9-250426

  However, if the discharge characteristics are set as described above, an amount of fuel that satisfies the requirement can be discharged at the start of the engine with a large amount of required fuel (very low rotational speed range), but in other rotational speed ranges. More fuel than the required amount of fuel is discharged. The difference between the required amount of fuel and the amount of fuel actually discharged becomes surplus fuel, and the discharge operation of the fuel supply apparatus corresponding to that amount is wasted. In particular, in the extremely low rotation speed region, the above-described reduction in volumetric efficiency is large, so that surplus fuel is further increased, and the above-described problem becomes more remarkable.

  In Patent Document 1, a bypass flow path that bypasses the intake metering valve and the high-pressure pump is connected in parallel to the fuel flow path, and an open / close valve in the middle of the bypass flow path is connected to the fuel pressure in the delivery pipe from the feed pressure. By opening the valve when the engine pressure is low, the fuel pressure is immediately increased to the feed pressure when the engine is started to reduce the pressure increase time.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a fuel for an internal combustion engine that can supply a required amount of fuel to a fuel injection valve without excess or deficiency over the entire rotational speed range of the internal combustion engine. It is to provide a supply device.

In the following, means for achieving the above object and its effects are described.
(1) The invention according to claim 1 is a fuel supply apparatus for an internal combustion engine in which a low-pressure pump and a high-pressure pump are provided in a fuel flow path connecting a fuel tank and a fuel injection valve. A first bypass passage that bypasses the pump and is connected in parallel to the fuel passage; a second bypass passage that bypasses the high-pressure pump and is connected in parallel to the fuel passage; The fuel flow path is switched between after the engine is started and when the engine is started, the fuel in the fuel tank is supplied to the fuel injection valve via the first bypass flow path and the high-pressure pump. And a flow path of fuel supplied to the fuel injection valve via the low pressure pump and the second bypass flow path, and after the engine is started, the fuel in the fuel tank is transferred to the low pressure pump and the high pressure pump. Switching means for forming a flow path of the fuel supplied to the fuel injection valve in order, and the first bypass flow path has an upstream end upstream of the low-pressure pump and the first bypass flow path. It is connected to the fuel flow path, and its downstream end is connected to the fuel flow path between the low-pressure pump and the high-pressure pump, and the upstream end of the second bypass flow path is the first bypass flow path. The downstream end is connected to the fuel flow path between the low pressure pump and the low pressure pump, and the downstream end is connected to the fuel flow path downstream of the high pressure pump. A first on-off valve that is provided in the bypass passage and opens only when the engine is started; and is provided between the upstream end of the second bypass passage and the downstream end of the first bypass passage in the fuel passage. Second open that closes only when the engine starts A valve and a third on-off valve that opens only when the engine is started and allows the flow of fuel from the upstream to the downstream of the second bypass flow path, and the fuel flow path is the second open / close An intake metering valve that adjusts an amount of fuel sucked into the high-pressure pump by changing a degree of restriction of the passage of fuel between the valve and the high-pressure pump; And the second on-off valve and the intake metering valve are provided at a junction at the downstream end of the first bypass passage with respect to the fuel passage, and the first on-off valve and the second on-off valve are Reciprocating a common main valve element to open or close the downstream end of the first bypass passage with respect to the fuel passage and to open and close the fuel passage upstream of the intake metering valve. The main valve body is the suction metering valve A first open / close position that closes the fuel flow path upstream and communicates the downstream end of the first bypass flow path with the fuel flow path, and the downstream end of the first bypass flow path for the fuel flow. The cylinder is provided so as to be reciprocable between a second opening and closing position that is closed with respect to the passage and opens the fuel flow path upstream of the intake metering valve, and has a communication hole. The main valve body is configured so that the internal space and the communication hole thereof are part of the fuel flow path, and the intake metering valve is provided in the main valve body to the main valve body. A secondary valve body that moves, by adjusting an overlapping amount of the communication hole of the main valve body and the communication hole of the secondary valve body through relative movement of the main valve body and the secondary valve body; The gist is that the amount of fuel sucked into the high-pressure pump is adjusted.

  According to the above configuration, when the engine is started, a part of the fuel in the fuel tank is directly sucked by the operation of the high-pressure pump according to the switching of the flow path by the switching means. Due to this suction, in the process of flowing through the fuel flow path, the fuel separates from the fuel flow path upstream from the low pressure pump and flows into the first bypass flow path. After passing through the first bypass flow path, the fuel joins the fuel flow path between the low pressure pump and the high pressure pump. Then, the fuel is sucked into the high-pressure pump and pressurized, and then discharged. The amount of fuel discharged from the high-pressure pump is smaller than when passing through the low-pressure pump and the high-pressure pump in this order. Moreover, the pressure of the fuel discharged from the high pressure pump is lower than that in the case of passing through the low pressure pump and the high pressure pump in this order. The fuel discharged from the high-pressure pump is sent to the fuel injection valve through the fuel flow path.

  Further, according to the switching, a part of the fuel in the fuel tank is sucked by the operation of the low pressure pump. By this suction, the fuel is sucked into the low-pressure pump through the fuel flow path, and is discharged after being pressurized. The amount of fuel discharged from the low-pressure pump is larger than when passing through the low-pressure pump and the high-pressure pump in this order. Moreover, the pressure of the fuel discharged from the low pressure pump is lower than that in the case of passing through the low pressure pump and the high pressure pump in this order. The fuel discharged from the low pressure pump separates from the fuel flow path between the low pressure pump and the high pressure pump and flows into the second bypass flow path. This fuel passes through the second bypass flow path, and then merges with the fuel flow path downstream from the high-pressure pump. Together with the fuel that has passed through the first bypass flow path and the high-pressure pump in turn, the fuel is injected into the fuel injection valve. Sent.

  As a result, when the engine is started, the total amount discharged by each of the high-pressure pump and the low-pressure pump is larger than the case where the low-pressure pump and the high-pressure pump are sequentially passed. Further, when the engine is started, fuel having a fuel pressure lower than that in the case of passing through the low pressure pump and the high pressure pump in order is supplied to the fuel injection valve. Therefore, in the extremely low rotational speed range at the time of starting the engine, more fuel is required than when passing through the low-pressure pump and the high-pressure pump in order, but this requirement can be satisfied. Further, when starting the engine, although it is not as high as when passing through the low-pressure pump and the high-pressure pump in order, a moderate fuel pressure is required for the ignition of the fuel, this requirement can be satisfied.

  Further, after the engine is started, the fuel in the fuel tank is sucked by the low pressure pump in accordance with the switching of the flow path by the switching means. By this suction, the fuel flows only through the fuel flow path without flowing through the first bypass flow path and the second bypass flow path. That is, the fuel in the fuel tank is sucked by the low pressure pump and the pressure is increased. A large amount of fuel is discharged from the low-pressure pump, although the fuel pressure is lower than that of the high-pressure pump alone. The fuel discharged in this way is sucked up by the high-pressure pump and the pressure is increased. From the high-pressure pump, a small amount of fuel having a higher fuel pressure than that at the time of passing through the low-pressure pump is discharged and sent to the fuel injection valve. Therefore, in the engine speed range after the engine is started, a smaller amount of fuel is required at a higher fuel pressure than when the engine is started (very low speed range), but this requirement can be satisfied.

Thus, according to the first aspect of the present invention, the required amount of fuel can be supplied to the fuel injection valve without excess or deficiency over the entire rotational speed range of the internal combustion engine .

Also, according to the above configuration, the first on-off valve is opened at the time of engine startup, the second on-off valve is closed. Further, the third on-off valve is opened, and the fuel is allowed to flow from upstream to downstream of the second bypass flow path.

  The first bypass channel is opened by opening the first on-off valve, and fuel can be distributed in the first bypass channel. Therefore, due to the operation of the high pressure pump, a part of the fuel in the fuel tank flows into the first bypass passage while flowing through the fuel passage, and after passing through the first bypass passage, Also joins the fuel flow path downstream. This fuel is sucked into the high-pressure pump and boosted to be discharged. The amount of fuel discharged from the high-pressure pump is smaller than when passing through the low-pressure pump and the high-pressure pump in this order. Moreover, the pressure of the fuel discharged from the high pressure pump is lower than that in the case of passing through the low pressure pump and the high pressure pump in this order. The fuel discharged from the high-pressure pump is sent to the fuel injection valve through the fuel flow path. Since the second on-off valve is closed, the fuel that has joined the fuel passage from the downstream end of the first bypass passage does not flow to the upstream side (second on-off valve side).

  Further, when the engine is started, a part of the fuel in the fuel tank is sucked into the low-pressure pump through the fuel flow path by the operation of the low-pressure pump, and is pressurized and discharged. The amount of fuel discharged from the low-pressure pump is larger than when passing through the low-pressure pump and the high-pressure pump in this order. Moreover, the pressure of the fuel discharged from the low pressure pump is lower than that in the case of passing through the low pressure pump and the high pressure pump in this order. The fuel discharged from the low-pressure pump flows downstream in the fuel flow path, but the second on-off valve is closed and the third on-off valve is opened. It flows into the second bypass channel upstream. The fuel passes through the second bypass flow path and the third on-off valve in order, and then merges with the fuel flow path, and is sent to the fuel injection valve together with the fuel that has passed through the first bypass flow path and the high-pressure pump in order. It is done.

As a result, at the time of starting the engine, the amount of fuel is larger than that when passing through the low-pressure pump and the high-pressure pump in order, and fuel with a low pressure is supplied to the fuel injection valve.
On the other hand, after the engine is started, both the first on-off valve and the third on-off valve are closed, and the second on-off valve is opened. The first bypass flow path is closed by closing the first on-off valve, and the fuel does not flow through the first bypass flow path. Therefore, the operation of the low-pressure pump causes the fuel in the fuel tank to be sucked into the low-pressure pump through the fuel flow path and boosted without flowing into the first bypass flow path. The low-pressure pump discharges a larger amount of fuel, although at a lower pressure than the high-pressure pump alone. Further, the second bypass flow path is closed by closing the third on-off valve, and the fuel does not flow through the second bypass flow path. Therefore, the fuel discharged from the low pressure pump flows through the fuel flow path without flowing into the second bypass flow path, is sucked into the high pressure pump, and is pressurized. From the high pressure pump, higher pressure fuel is discharged than when discharged from the low pressure pump.

As a result, in the engine speed range after the engine is started, a smaller amount of fuel can be supplied to the fuel injection valve at a higher fuel pressure than when the engine is started (very low speed range).
Further, according to the above configuration, after the engine is started, the fuel discharged from the low pressure pump is sucked into the high pressure pump through the second on-off valve and the suction metering valve. When the fuel passes through the intake metering valve, the passage of the fuel is restricted by the intake metering valve, and the degree of restriction is changed. This change adjusts the amount of fuel drawn into the high-pressure pump.
Moreover, according to said structure, a 1st on-off valve, a 2nd on-off valve, and an intake metering valve are arrange | positioned in the state collected by the confluence | merging part of the 1st bypass flow path with respect to a fuel flow path. For this reason, it is possible to share parts, and it is possible to reduce the size of the fuel supply device as compared with the case where the valves are arranged apart from each other.
According to the above configuration, when the main valve element moves to the first opening / closing position by reciprocation, the fuel flow path is closed upstream of the intake metering valve, and the downstream end of the first bypass flow path is the fuel flow path. Is communicated to. Further, when the main valve body moves to the second opening / closing position, the downstream end of the first bypass passage is blocked from the fuel passage, and the fuel passage is opened upstream of the intake metering valve. As described above, the main valve body reciprocates between the first opening / closing position and the second opening / closing position, whereby each opening / closing of the first bypass passage and the fuel passage is performed. The effect of is obtained with certainty.
According to the above configuration, when the main valve element moves to the second opening / closing position, the fuel flows through the internal space of the main valve element and the respective communication holes of the main valve element and the sub-valve element as fuel flow paths. . At this time, in the intake metering valve, the sub-valve element moves relative to the main valve element to adjust the overlapping amount of the two communication holes, thereby adjusting the fuel.

(2) The invention according to claim 2 is a fuel supply apparatus for an internal combustion engine in which a low-pressure pump and a high-pressure pump are provided in a fuel flow path connecting a fuel tank and a fuel injection valve. A first bypass passage that bypasses the pump and is connected in parallel to the fuel passage; a second bypass passage that bypasses the high-pressure pump and is connected in parallel to the fuel passage; The fuel flow path is switched between after the engine is started and when the engine is started, the fuel in the fuel tank is supplied to the fuel injection valve via the first bypass flow path and the high-pressure pump. And a flow path of fuel supplied to the fuel injection valve via the low pressure pump and the second bypass flow path, and after the engine is started, the fuel in the fuel tank is transferred to the low pressure pump and the high pressure pump. Switching means for forming a flow path of the fuel supplied to the fuel injection valve in order, and the first bypass flow path has an upstream end upstream of the low-pressure pump and the first bypass flow path. It is connected to the fuel flow path, and its downstream end is connected to the fuel flow path between the low-pressure pump and the high-pressure pump, and the upstream end of the second bypass flow path is the first bypass flow path. The downstream end is connected to the fuel flow path between the low pressure pump and the low pressure pump, and the downstream end is connected to the fuel flow path downstream of the high pressure pump. A first on-off valve that is provided in the bypass passage and opens only when the engine is started; and is provided between the upstream end of the second bypass passage and the downstream end of the first bypass passage in the fuel passage. Second open that closes only when the engine starts A valve and a third on-off valve that opens only when the engine is started and allows the flow of fuel from the upstream to the downstream of the second bypass flow path, and the fuel flow path is the second open / close An intake metering valve that adjusts an amount of fuel sucked into the high-pressure pump by changing a degree of restriction of the passage of fuel between the valve and the high-pressure pump; And the second on-off valve and the intake metering valve are provided at a junction at the downstream end of the first bypass passage with respect to the fuel passage, and the first on-off valve reciprocates the main valve body. The downstream end of the first bypass passage is communicated with or shut off from the fuel passage by moving the second on-off valve and the intake metering valve in addition to the main valve body, It is provided in the main valve body and moves relative to the main valve body. Each of the main valve body and the sub-valve body is provided with a communication hole, and the second on-off valve is formed between the main valve body and the sub-valve body. The suction metering valve is opened and closed by changing whether or not the communication hole of the main valve body and the communication hole of the sub-valve body overlap each other through relative movement, and the suction metering valve is the main valve Adjusting the amount of fuel sucked into the high-pressure pump by adjusting the amount of overlap between the communication hole of the main valve body and the communication hole of the sub-valve body through relative movement of the body and the sub-valve body There is a summary.

According to said structure, in a 1st on-off valve, the downstream end of a 1st bypass flow path is connected or interrupted | blocked with respect to a fuel flow path by reciprocating a main valve body.
  On the other hand, in the second on-off valve, the positional relationship between the communication holes of both the main and sub-valve elements changes as the sub-valve element is relatively moved within the main valve element. When both communication holes overlap, the fuel flow path is opened upstream of the intake metering valve, and when there is no overlap, the fuel flow path is closed.
  In the intake metering valve, fuel is metered by adjusting the amount of overlap between the two communication holes by relatively moving the sub-valve in the main valve body.
  In this way, by causing the main valve body to reciprocate and moving the sub-valve element relative to the main valve body, the first on-off valve, the second on-off valve, and the intake metering valve can perform their respective functions. Is possible.

(3) The invention according to claim 3 is the fuel supply apparatus for an internal combustion engine according to claim 2, wherein the downstream end of the first bypass passage is in communication with the fuel passage. When the communication hole of the main valve body and the communication hole of the sub-valve body are maintained in a state that does not overlap each other, and the downstream end of the first bypass flow path is blocked from the fuel flow path, the main valve body The main point is that the communication hole of the main valve body and the communication hole of the sub valve body are maintained in either a non-overlapping state or a overlapping state depending on the positional relationship between the main valve body and the sub-valve body.
  By providing both communication holes at a location satisfying the above conditions, when the downstream end of the first bypass flow path communicates with the fuel flow path by the main valve body, the two communication holes do not overlap with each other, and suction control is performed. The fuel flow path is closed upstream of the quantity valve. In addition, when the main valve body cuts off the communication with the fuel flow path at the downstream end of the first bypass flow path, when the sub-valve element moves relative to the main valve body in this state, the two communication holes overlap each other, and the suction control is performed. The fuel flow path is opened upstream of the quantity valve. Further, the amount of overlap between the two communication holes is changed in accordance with the amount of relative movement of the sub-valve, and fuel metering is performed.
  Thus, the main valve body moves and the sub-valve element moves relative to the main valve body, whereby the fuel flow path is opened and closed upstream of the intake metering valve and the fuel is metered.

(4) According to a fourth aspect of the present invention, in the fuel supply device for an internal combustion engine according to the third aspect, the main valve is arranged in a direction in which the downstream end of the first bypass passage is communicated with the fuel passage. A first urging member for urging the body, and a second urging member provided between the main valve body and the sub-valve body to urge the main valve body in a direction opposite to the first urging member. The gist is to further include a member.
  According to said structure, when a subvalve body moves, the movement will be transmitted to a main valve body via a 2nd biasing member. Then, the main valve body is displaced in a direction in which the urging force of the first urging member and the urging force of the second urging member are balanced. Due to the displacement of the main valve body, the downstream end of the first bypass passage is connected to or cut off from the fuel passage. Due to the displacement of the sub-valve element, the fuel flow path is opened and closed upstream of the intake metering valve, and fuel metering is performed.

(5) According to a fifth aspect of the present invention, in the fuel supply device for an internal combustion engine according to the fourth aspect, the urging force of the second urging member is set larger than the urging force of the first urging member. This is the gist.
  According to the above configuration, when the downstream end of the first bypass channel is in communication with the fuel channel, the two communication holes do not overlap each other, and the fuel channel is closed upstream of the intake metering valve. . From this state, when the sub-valve element is displaced in a direction that blocks the communication between the downstream end of the first bypass flow path and the fuel flow path, the urging force of the second urging member is changed to the urging force of the first urging member. Therefore, the main valve body is displaced in the same direction as the sub valve body is displaced. When the communication is blocked by the main valve body and the displacement of the main valve body stops, only the sub-valve body is displaced. Thus, when communication with the fuel flow path at the downstream end of the first bypass flow path is interrupted, the sub-valve element moves relative to the main valve element with a slight delay. Then, with this relative movement, the positional relationship between the two communication holes changes, and the two communication holes overlap to enable fuel to be sent to the intake metering valve and the high-pressure pump. Therefore, it is possible to suppress the fuel that has passed through the intake metering valve from leaking to the first bypass flow path side, and to send the fuel to the high-pressure pump at an early stage so that the fuel pressure can be quickly increased to the required fuel pressure. .

(6) The invention according to claim 6 is the fuel supply apparatus for an internal combustion engine according to any one of claims 1 to 5, wherein the intake metering valve is provided from a downstream end of the first bypass flow path. Is also provided on the upstream side.
  According to the above configuration, when the engine is started, the fuel that has separated from the fuel flow path and flows into the first bypass flow path joins the fuel flow path downstream of the intake metering valve. The fuel is sucked into the high-pressure pump without passing through the intake metering valve, that is, without being restricted in passage. Accordingly, more fuel is sucked into the high-pressure pump than when passing through the intake metering valve, so that more fuel is efficiently supplied to the fuel injection valve.

(7) The invention according to claim 7 is the fuel supply device for an internal combustion engine according to any one of claims 1 to 6, wherein the intake metering valve has a variable cross-sectional area of the fuel flow path. The gist is that it consists of a throttle valve.
  According to the above configuration, when the fuel discharged from the low-pressure pump passes through the intake valve through the second on-off valve, the cross-sectional area of the fuel flow path is changed by the throttle valve, so that the fuel The passage is restricted and the degree of restriction is changed.

(8) The invention according to claim 8 is provided in a fuel tank that stores fuel, a fuel injection valve that injects fuel, a fuel flow path that connects the fuel tank and the fuel injection valve, and a fuel flow path. In a fuel supply device for an internal combustion engine comprising a low pressure pump and a high pressure pump for pressurizing fuel, the fuel supply device switches a fuel flow path in the fuel path to a different one between when the engine is started and after the engine is started. The switching unit further includes a switching unit configured to cause the fuel to flow from the fuel tank to the fuel injection valve via only the low-pressure pump of the low-pressure pump and the high-pressure pump when the engine is started. And a second distribution path through which fuel flows from the fuel tank to the fuel injection valve via only the high-pressure pump of the low-pressure pump and the high-pressure pump. And after the engine is started, the third low-pressure pump and the high-pressure pump pass through these pumps in order to form a third flow path through which the fuel flows from the fuel tank to the fuel injection valve. Is the gist.
  (9) The invention according to claim 9 is the fuel supply apparatus for an internal combustion engine according to claim 8, wherein the fuel supply apparatus is provided between the low-pressure pump and the high-pressure pump, and is provided from the low-pressure pump. A suction metering valve that adjusts a flow rate of the fuel that is discharged and flows into the high-pressure pump, and the switching means includes, as the third flow path, the low-pressure pump, the suction amount metering valve, and The gist of the invention is that it forms a passage through which fuel flows in the order of the high-pressure pump.

(10) The invention according to claim 10 is the fuel supply device for an internal combustion engine according to claim 8 or 9, wherein the fuel flow path is a first flow connecting the fuel tank and an inlet of the low-pressure pump. A second flow path connecting the outlet, the low pressure pump outlet and the high pressure pump inlet, a third flow path connecting the high pressure pump outlet and the fuel injection valve, and bypassing the low pressure pump A low pressure bypass flow path connecting the first flow path and the second flow path, and connecting the second flow path and the third flow path bypassing the high pressure pump. It includes a high-pressure bypass flow path that connects the second flow path portion and the third flow path that are closer to the low-pressure pump than the connection portion of the low-pressure bypass flow path with respect to two flow paths. And the switching means includes the second flow path, the low pressure bypass flow path, and the high pressure bypass flow. By switching the open / close state of the flow path, the first flow path and the second flow path are formed as a fuel flow path when the engine is started, and the third flow path is set as the fuel flow path after the engine is started. The gist is that it is formed.

(11) The invention according to claim 11 is the fuel supply apparatus for an internal combustion engine according to claim 10, wherein the switching means serves as the first flow path, the first flow path, the low-pressure pump, and the A path through which fuel flows is formed in the order of the high-pressure bypass flow path and the third flow path, and the first flow path, the low-pressure bypass flow path, the second flow path, and the high-pressure pump are used as the second flow path. And a path through which fuel flows in the order of the third flow path, and a path through which fuel flows in the order of the first flow path, the second flow path, and the third flow path as the third flow path. The gist is that it is formed.

(12) The invention according to a twelfth aspect is the internal combustion engine fuel supply apparatus according to the tenth or eleventh aspect, wherein the switching means includes a branch point of the second flow path and the high-pressure bypass flow path. The part between the branch point of the low-pressure bypass flow path and the branch point is used as an inter-branch flow path, and when the engine is started, the low-pressure bypass flow path and the high-pressure bypass flow path are opened and the flow path between the branch points is closed. By forming the first flow path and the second flow path by closing the low-pressure bypass flow path and the high-pressure bypass flow path after starting the engine and opening the inter-branch flow path The gist is to form the third distribution channel.

(13) The invention according to claim 13 is the fuel supply apparatus for an internal combustion engine according to claim 8 or 9, wherein the fuel flow path is connected to the fuel tank at the inlet and has two passages at the outlet. A first common flow path that branches off, a second common flow path whose outlet is connected to the fuel injection valve and two passages merge at the inlet, an outlet of the first common flow path, and an inlet of the low-pressure pump A first branch channel that connects the outlet, a second branch channel that connects an outlet of the low-pressure pump and an inlet of the second common channel, an outlet of the first supply channel, and an inlet of the high-pressure pump A third branch channel that connects the outlet, a fourth branch channel that connects an outlet of the high-pressure pump and an inlet of the second supply channel, the second branch channel and the third branch channel Including an intermediate branch flow path to be connected. The means includes a communication state of the first common flow channel with respect to the third branch flow channel, a communication state of the intermediate branch flow channel with respect to the third branch flow channel, and the second branch flow with respect to the second common flow channel. By switching the communication state of the road, the first distribution path and the second distribution path are formed as a fuel distribution path when the engine is started, and the third distribution path is formed as a fuel distribution path after the engine is started. The gist is to do.

(14) The invention according to claim 14 is the fuel supply apparatus for an internal combustion engine according to claim 13, wherein the switching means serves as the first common flow path and the first branch as the first flow path. A flow path is formed in the order of the flow path, the low-pressure pump, the second branch flow path, and the second common flow path, and the first common flow path and the third branch are formed as the second flow path. A flow path is formed in the order of the flow path, the high-pressure pump, the fourth branch flow path, and the second common flow path, and the first common flow path and the first branch are formed as the third flow path. The fuel flows in the order of the flow path, the low pressure pump, the second branch flow path, the intermediate branch flow path, the third branch flow path, the high pressure pump, the fourth branch flow path, and the second common flow path. Summary that it forms a route It is.

(15) The invention according to claim 15 is the fuel supply apparatus for an internal combustion engine according to claim 13 or 14, wherein the switching means is arranged in the third branch flow path from the outlet of the first common flow path. The connection to the intermediate branch flow path is the third branch flow path upstream, and the connection from the intermediate branch flow path to the inlet of the high pressure pump in the third branch flow path is the third branch flow path downstream. As a communication state between the third branch flow channel upstream portion, the third branch flow channel downstream portion and the intermediate branch flow channel, and a communication state between the second branch flow channel and the second common flow channel When the engine is started, the third branch flow path upstream part and the third branch flow path downstream part communicate with each other, and the third branch flow path and the intermediate branch flow path Between the second branch channel and the second common channel. Thereby forming the first flow path and the second flow path, and after starting the engine, shuts off the upstream portion of the third branch flow path and the downstream portion of the third branch flow path, and The third flow path is established by communicating between the intermediate branch flow path and the downstream portion of the third branch flow path and blocking between the second branch flow path and the second common flow path. The gist is that it is formed.

(16) The invention according to claim 16 is the fuel supply apparatus for an internal combustion engine according to claim 15, wherein the switching means includes a port A to which the downstream portion of the third branch flow path is connected and the intermediate branch flow. A port B to which a path is connected, a port C to which the upstream portion of the third branch flow path is connected, and a valve body that switches a communication state between the ports by movement with respect to these ports, When in the first open / close position, the port A and the port C communicate with each other and the port A and the port B are blocked, whereby the third branch flow path upstream portion and the first The port communicates with the downstream portion of the three-branch channel and blocks between the third branch channel and the intermediate branch channel, and the port is located when the valve body is in the second opening / closing position. Block between A and port C and front The port A and the port B communicate with each other, thereby blocking between the upstream portion of the third branch flow channel and the downstream portion of the third branch flow channel, and the intermediate branch flow channel and the third branch flow The gist is that it communicates with the downstream of the road.

(17) The invention according to claim 17 is the fuel supply apparatus for an internal combustion engine according to claim 15, wherein the switching means includes a port A to which the downstream portion of the third branch flow path is connected and the intermediate branch flow. A port B to which a path is connected and a port C to which the upstream portion of the third branch flow path is connected, and a valve body and an auxiliary valve body for switching a communication state between the ports by movement with respect to these ports, When the valve body is in the first open / close position and the auxiliary valve body is in the first adjustment position, the port A communicates with the port C and between the port A and the port B. And thereby communicating between the upstream portion of the third branch flow channel and the downstream portion of the third branch flow channel and blocking between the third branch flow channel and the intermediate branch flow channel. And the valve body is in the second open / close position. And when the auxiliary valve body is in the second adjustment position, the port A and the port C are blocked and the port A and the port B are communicated, thereby the third branch flow. The gist is that the upstream portion of the road and the downstream portion of the third branch channel are blocked and the intermediate branch channel and the downstream portion of the third branch channel are communicated .
(18) According to an eighteenth aspect of the present invention, in the fuel supply device for an internal combustion engine according to the seventeenth aspect, the switching means is configured such that the valve body is in the second opening / closing position and the auxiliary valve body is in the second position. When in the first open / close position, the port A and the port C are blocked and the port A and the port B are blocked, thereby the third branch flow path upstream portion and the first The gist of the invention is to block between the downstream portion of the three-branch channel and to block between the third branch channel and the intermediate branch channel .

(19) The invention according to claim 19 is provided in a fuel tank for storing fuel, a fuel injection valve for injecting fuel, a fuel flow path connecting the fuel tank and the fuel injection valve, and a fuel flow path. In a fuel supply device for an internal combustion engine comprising a low pressure pump and a high pressure pump for pressurizing fuel, the fuel supply device switches a fuel flow path in the fuel path to a different one between when the engine is started and after the engine is started. The switching unit further includes a switching unit configured to cause the fuel to flow from the fuel tank to the fuel injection valve via only the low-pressure pump of the low-pressure pump and the high-pressure pump when the engine is started. And a second flow in which the fuel flows from the fuel tank to the fuel injection valve via only the high-pressure pump of the low-pressure pump and the high-pressure pump. And a third flow path through which the fuel passes through the low-pressure pump and the high-pressure pump in this order and flows from the fuel tank to the fuel injection valve after the engine is started. The fuel flow path includes a first common flow path having an inlet connected to the fuel tank and branching into two passages at an outlet, and an outlet connected to the fuel injection valve and two passages at the inlet. A second common channel that merges, a first branch channel that connects an outlet of the first common channel and an inlet of the low-pressure pump, an outlet of the low-pressure pump and an inlet of the second common channel. A second branch channel to be connected; a third branch channel connecting an outlet of the first supply channel and an inlet of the high pressure pump; an outlet of the high pressure pump and an inlet of the second supply channel; Connected fourth branch flow path And the intermediate branch flow path connecting the second branch flow path and the third branch flow path, and the switching means includes the first common flow with respect to the third branch flow path. By switching the communication state of the road, the communication state of the intermediate branch flow channel with respect to the third branch flow channel, and the communication state of the second branch flow channel with respect to the second common flow channel, the fuel flow at engine startup The first circulation path and the second circulation path are formed as a path, and the third circulation path is formed as a fuel circulation path after the engine is started. From the exit of the road to the connection portion with the intermediate branch flow channel in the third branch flow channel is the third branch flow channel upstream portion, and the high pressure from the connection portion with the intermediate branch flow channel in the third branch flow channel The downstream of the third branch channel up to the pump inlet The communication state between the upstream portion of the third branch flow channel, the downstream portion of the third branch flow channel, and the intermediate branch flow channel, and the communication between the second branch flow channel and the second common flow channel When the engine is started, the third branch flow path upstream portion and the third branch flow path downstream portion are communicated, and the third branch flow path and the intermediate branch flow are switched. After the engine is started, the first flow path and the second flow path are formed by blocking the passage and communicating between the second branch flow path and the second common flow path. The third branch flow path upstream part and the third branch flow path downstream part, and between the intermediate branch flow path and the third branch flow path downstream part, and The third flow path is formed by blocking between the second branch flow path and the second common flow path. The switching means includes a port A to which the downstream portion of the third branch flow path is connected, a port B to which the intermediate branch flow path is connected, a port C to which the upstream portion of the third branch flow path is connected, and these ports. A valve body that switches a communication state between the ports by movement, and communicates between the port A and the port C when the valve body is in the first open / close position, and the port A Blocking between the port B and thereby communicating between the upstream portion of the third branch flow path and the downstream portion of the third branch flow path, and between the third branch flow path and the intermediate branch flow path And when the valve body is in the second open / close position, the port A and the port C are blocked and the port A and the port B are communicated with each other. The third branch flow path upstream and the third branch And the intermediate branch flow path and the third branch flow path downstream section are communicated with each other, and the switching means is configured such that the valve body is in the second opening / closing position. At some time, fuel is circulated from the port B to the port A through a valve body passage provided in the valve body, and the opening area of the valve body passage is changed to change the port B to the port A. The gist of the invention is that it includes an intake metering valve that adjusts the flow rate of the flowing fuel .
(20) The invention according to claim 20 is the fuel supply apparatus for an internal combustion engine according to claim 19, wherein the switching means is provided on the inlet side of the valve body passage and moves relative to the valve body. The gist of the invention is that it further includes an auxiliary valve body that changes the opening area of the inlet of the valve body passage .

(21) The invention according to claim 21 is the fuel supply apparatus for an internal combustion engine according to claim 20, wherein the switching means is configured such that the valve body is in the second opening / closing position and the auxiliary valve body is in the first position. A part of the inlet of the valve body passage is closed by the auxiliary valve body when the valve body is in the first adjustment position, the valve body is in the second opening / closing position, and the auxiliary valve body is in the second position. The gist is that the inlet of the valve body passage is opened from the auxiliary valve body when in the adjustment position .

(22) The invention according to claim 22 is the fuel supply device for an internal combustion engine according to any one of claims 19 to 21, wherein the switching means is based on an engine operating state after engine start. By changing the opening area of the valve body passage, the inter-port flow rate, which is the flow rate of fuel flowing from the port B to the port A, is adjusted, and the engine operating state is based on the low load operating state. The inter-port flow rate is set to the first flow rate on the small flow rate side, and the inter-port flow rate is set to the second flow rate on the large flow rate side based on the engine operation state being the high load operation state. It is a summary.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is embodied in a fuel supply device for a diesel engine will be described with reference to FIGS. 1, 2, and 10.

  As shown in FIG. 1, the fuel supply device 11 includes a low pressure pump (feed pump) 15 and a high pressure pump in a fuel flow path 14 that connects a fuel tank 12 and a fuel injection valve 13 of a diesel engine (hereinafter simply referred to as an engine) 10. 16 is provided. The low pressure pump 15 and the high pressure pump 16 are arranged in series in this order from the fuel tank 12 toward the fuel injection valve 13, and are both driven by the engine 10. A first bypass passage 17 bypasses the low pressure pump 15 and is connected to the fuel passage 14 in parallel. The upstream end of the first bypass channel 17 is connected to the fuel channel 14 upstream of the low pressure pump 15, and the downstream end is connected to the fuel channel 14 between the low pressure pump 15 and the high pressure pump 16. A second bypass passage 18 is connected to the fuel passage 14 in parallel so as to bypass the high-pressure pump 16. The upstream end of the second bypass passage 18 is connected to the fuel passage 14 between the downstream end of the first bypass passage 17 and the low pressure pump 15, and the downstream end is connected to the fuel passage 14 downstream of the high pressure pump 16. It is connected.

  The fuel supply device 11 is provided with switching means for switching the fuel flow path between when the engine 10 is started and after it is started. The flow path when the engine 10 is started by the switching means supplies fuel to the fuel injection valve 13 via the first bypass flow path 17 and the high-pressure pump 16 as shown by a thick line in FIG. This is a flow path that is supplied to the fuel injection valve 13 via the pump 15 and the second bypass flow path 18. Further, the flow path after the engine 10 is started is a flow path for supplying the fuel in the fuel tank 12 to the fuel injection valve 13 through the low pressure pump 15 and the high pressure pump 16 in this order, as indicated by a thick line in FIG. is there.

  The switching means includes the first on-off valve 21, the second on-off valve 22, the third on-off valve 23, and the electronic control device 24 that controls the first on-off valve 21, the second on-off valve 22, etc. according to the operating state of the engine 10. With. A signal related to the state (on / off) of the ignition (IG) switch 29 is input to the electronic control unit 24 as a signal related to the operating state of the engine 10. The ignition switch 29 is a switch operated by the driver for starting or stopping the engine 10, and is turned on for starting and turned off for stopping. When the engine is stopped, the ignition switch 29 is off. In addition, detection signals from various sensors 30 provided in the engine 10 and the like are input to the electronic control unit 24. These sensors include, for example, a throttle sensor that detects the opening degree of the throttle valve (throttle opening) provided in the intake passage of the engine 10, an accelerator sensor that detects the amount of depression of the accelerator pedal by the driver, and an intake passage An intake pressure sensor or the like that detects pressure (intake pressure) may be used. The detection values of these sensors are used, for example, for calculating the engine load or the like in the electronic control unit 24.

  The first on-off valve 21 is provided in the first bypass passage 17 and is opened only when the engine 10 is started by the electronic control unit 24. The second on-off valve 22 is provided between the upstream end of the second bypass passage 18 and the downstream end of the first bypass passage 17 in the fuel passage 14, and is closed only when the engine 10 is started by the electronic control unit 24. Is done. The third on-off valve 23 is a valve that opens only when the engine 10 is started and allows the fuel to flow from upstream to downstream of the second bypass passage 18. The third on-off valve 23 includes a valve seat 25, a valve body 26 disposed on the downstream side of the valve seat 25, and a spring 27 disposed on the downstream side of the valve body 26. In the third on-off valve 23, the second bypass flow path 18 is closed when the valve body 26 contacts the valve seat 25, and the second bypass flow path 18 is opened when the valve body 26 is separated from the valve seat 25. The The spring 27 always urges the valve body 26 toward the upstream side, that is, the side closing the second bypass flow path 18. In the third on-off valve 23 having such a configuration, only when the fuel pressure upstream of the third on-off valve 23 overcomes the downstream fuel pressure and the urging force of the spring 27 in the second bypass flow path 18. Open the valve. Such a situation only occurs when the engine 10 is started.

  With respect to the fuel flow path 14, between the second on-off valve 22 and the high-pressure pump 16 and upstream of the downstream end of the first bypass flow path 17, the intake metering controlled by the electronic control device 24 is provided. A valve 28 is provided. The intake metering valve 28 is for regulating the amount of fuel sucked into the high-pressure pump 16 by restricting the passage of fuel and changing the degree of restriction. The throttle valve has a variable area.

Next, the operation of the fuel supply device 11 configured as described above will be described separately when the engine 10 is started and after it is started.
<When starting engine 10>
When the ignition switch 29 is turned on by the driver to start the engine 10 from the state where the engine 10 is stopped, the first on-off valve 21 is opened by the electronic control unit 24 as shown in FIG. Then, the second on-off valve 22 is closed.

  The first bypass passage 17 is opened by opening the first on-off valve 21, and fuel can be distributed in the first bypass passage 17. A part of the fuel in the fuel tank 12 is sucked by the operation of the high-pressure pump 16. As a result of this suction, a part of the fuel flows into the first bypass passage 17 separately from the fuel passage 14 upstream of the low-pressure pump 15 in the course of flowing through the fuel passage 14 as shown by a thick line in FIG. To do. After passing through the first bypass flow path 17, the fuel joins the fuel flow path 14 downstream of the intake metering valve 28. The fuel is sucked into the high-pressure pump 16 without passing through the suction metering valve 28, that is, without being restricted in passage. The amount of fuel sucked is greater than that when the downstream end of the first bypass passage 17 is connected to the fuel passage 14 upstream of the suction metering valve 28 and the fuel passes through the suction metering valve 28. Many. Then, the sucked fuel is discharged after being pressurized by the high-pressure pump 16. The amount of fuel discharged from the high-pressure pump 16 is smaller than when passing through the low-pressure pump 15 and the high-pressure pump 16 in order. Further, the pressure of the fuel discharged from the high pressure pump 16 is lower than that in the case of passing through the low pressure pump 15 and the high pressure pump 16 in order. The fuel discharged from the high-pressure pump 16 is sent to the fuel injection valve 13 through the fuel flow path 14. In this way, more fuel is supplied to the fuel injection valve 13 more efficiently than when passing through the intake metering valve 28.

Since the second on-off valve 22 is closed, the fuel joined from the downstream end of the first bypass passage 17 to the fuel passage 14 does not flow to the upstream side (second on-off valve 22 side). .
When the engine 10 is started, a part of the fuel in the fuel tank 12 is sucked by the low pressure pump 15. By this suction, the fuel is sucked into the low-pressure pump 15 through the fuel flow path 14, and is discharged after being pressurized. The amount of fuel discharged from the low-pressure pump 15 is larger than when passing through the low-pressure pump 15 and the high-pressure pump 16 in order. Further, the pressure of the fuel discharged from the low pressure pump 15 is lower than that in the case of passing through the low pressure pump 15 and the high pressure pump 16 in order. The fuel discharged from the low pressure pump 15 flows toward the downstream side of the fuel flow path 14.

  Here, in addition to the second on-off valve 22 being closed, the fuel pressure upstream of the third on-off valve 23 in the second bypass flow path 18 is the fuel pressure on the downstream side and the biasing force of the spring 27. The third on-off valve 23 is opened by overcoming the above. By opening the valve, the fuel is allowed to flow from upstream to downstream of the second bypass passage 18. Therefore, fuel separates from the fuel flow path 14 upstream of the second on-off valve 22 and flows into the second bypass flow path 18. The fuel passes through the second bypass passage 18 and the third on-off valve 23, and then joins the fuel passage 14 downstream of the high-pressure pump 16, and sequentially passes through the first bypass passage 17 and the high-pressure pump 16 described above. It is sent to the fuel injection valve 13 together with the spent fuel.

  As a result, when the engine 10 is started, the fuel is supplied to the fuel injection valve 13 in a larger amount than when the low-pressure pump 15 and the high-pressure pump 16 are sequentially passed, and the fuel pressure is low. As shown in FIG. 10, a lot of fuel is required in the extremely low rotation speed region when the engine 10 is started, and this requirement is satisfied. At the same time, although the fuel pressure is not as high as when passing through the low-pressure pump 15 and the high-pressure pump 16 in order, a moderate fuel pressure is required for the ignition of the fuel, this requirement is also satisfied.

<After starting engine 10>
After the engine 10 is started, as shown in FIG. 2, the first on-off valve 21 is closed and the second on-off valve 22 is opened by the electronic control unit 24. The first bypass passage 17 is closed by closing the first on-off valve 21, and the fuel does not flow through the first bypass passage 17. Therefore, the fuel in the fuel tank 12 is sucked by the low pressure pump 15. As a result of this suction, the fuel flows through the fuel flow path 14 without flowing into the first bypass flow path 17 as shown by a thick line in FIG. That is, the fuel in the fuel tank 12 is sucked into the low-pressure pump 15 and the pressure is increased. A large amount of fuel is discharged from the low pressure pump 15 although the fuel pressure is lower than that of the high pressure pump 16 alone.

  The fuel discharged from the low pressure pump 15 is sucked by the high pressure pump 16. By this suction, the fuel passes through the second on-off valve 22 and the suction metering valve 28 in order. At this time, the passage of fuel is restricted by the intake metering valve 28. Further, the degree of the restriction is changed by changing the cross-sectional area of the fuel flow path 14 by the throttle valve constituting the intake metering valve 28. By this change, the amount of fuel sucked into the high-pressure pump 16 is adjusted. The fuel metered in this way is sucked into the high-pressure pump 16 and pressurized. From the high-pressure pump 16, a small amount of fuel whose fuel pressure is higher than that at the time of passing through the low-pressure pump 15 is discharged and sent to the fuel injector 13.

  Since the discharge pressure of the high pressure pump 16 is higher than the discharge pressure of the low pressure pump 15, the third on-off valve 23 is closed. The second bypass flow path 18 is closed by this valve closing, and the fuel does not flow through the second bypass flow path 18.

  In this way, the engine speed range after the engine 10 is started, that is, the speed range excluding the extremely low speed range when the engine 10 is started, is greater than when the engine 10 is started (very low speed range). A small amount of fuel is supplied to the fuel injection valve 13 at a high fuel pressure. As shown in FIG. 10, in the engine speed range after the engine 10 is started, a smaller amount of fuel is required at a higher fuel pressure than when the engine 10 is started (very low speed range). It is.

According to the first embodiment described in detail above, the following effects can be obtained.
(1) A first bypass flow path 17 that bypasses the low pressure pump 15 is connected in parallel to the fuel flow path 14, and a second bypass flow path 18 that bypasses the high pressure pump 16 is connected in parallel to the fuel flow path 14, and the engine The fuel flow path is switched at the time of starting 10 and after the starting. With this switching, when the engine 10 is started, fuel is supplied to the fuel injection valve 13 via the first bypass passage 17 and the high-pressure pump 16, and via the low-pressure pump 15 and the second bypass passage 18. The fuel is supplied to the fuel injection valve 13. Further, by the above switching, after the engine 10 is started, the fuel is supplied to the fuel injection valve 13 through the low pressure pump 15 and the high pressure pump 16 in order.

  Therefore, unlike the case where the fuel is passed through the low-pressure pump 15, the intake metering valve 28, and the high-pressure pump 16 in this order (corresponding to the background art) during and after the start of the engine 10, the characteristic line L4 in FIG. As shown, a large amount of fuel can be sent to the fuel injection valve 13 at a fuel pressure lower than that in the non-very low rotation speed region in the extremely low rotation speed region when the engine 10 is started. Further, in the engine speed range after the engine 10 is started, a smaller amount of fuel can be sent to the fuel injection valve 13 at a higher fuel pressure than when the engine 10 is started (very low speed range). In this way, the required amount of fuel can be supplied to the fuel injection valve 13 without excess or deficiency over the entire rotational speed range of the internal combustion engine. The surplus capacity of the fuel supply device 11 can be suppressed, and the fuel supply device 11 can be reduced in size and drive energy can be reduced as compared with the background art.

  (2) In the general fuel supply device 11, a plunger type pump is used as the high-pressure pump 16 in order to increase the volumetric efficiency. However, while this type of pump is highly efficient, its structure is complicated, and many plungers are used to avoid fuel pressure pulsation, resulting in a large number of parts and high cost.

  In this respect, in the first embodiment, it becomes easy to secure a large amount of fuel required when the engine 10 is started, so that the high-pressure pump 16 can be changed to a rotary type that is cheaper than the plunger type. Thus, the cost of the fuel supply device 11 can be reduced.

  (3) The upstream end of the first bypass passage 17 is connected to the fuel passage 14 upstream from the low pressure pump 15, and the downstream end is connected to the fuel passage 14 between the low pressure pump 15 and the high pressure pump 16. Further, the upstream end of the second bypass passage 18 is connected to the fuel passage 14 between the downstream end of the first bypass passage 17 and the low pressure pump 15, and the downstream end is connected to the fuel passage downstream of the high pressure pump 16. 14 is connected. Further, in order to switch the fuel flow path between when the engine 10 is started and after the engine is started, a first on-off valve 21 that opens only when the engine 10 is started is provided in the first bypass flow path 17. A second on-off valve 22 that only closes is provided between the upstream end of the second bypass passage 18 and the downstream end of the first bypass passage 17. Further, a third opening / closing valve 23 that opens only when the engine 10 is started and allows fuel to flow from upstream to downstream of the second bypass passage 18 is provided.

  By adopting such a configuration, it is possible to supply a large amount of fuel to the fuel injection valve 13 while ensuring the fuel pressure necessary for combustion in the extremely low rotation speed region when the engine 10 is started. In the engine rotation speed range after the start, the fuel pressure is higher than that at the start of the engine 10 (very low rotation speed range), and a small amount of fuel can be reliably supplied to the fuel injection valve 13.

  (4) The intake metering valve 28 is provided upstream of the downstream end of the first bypass flow path 17. For this reason, by providing the first bypass flow path 17 on the downstream side of the downstream end, more fuel is sucked into the high-pressure pump 16 than when the intake metering valve 28 is allowed to pass, and thus more when starting the engine. This fuel can be efficiently supplied to the fuel injection valve 13.

(Second Embodiment)
Next, a second embodiment embodying the present invention will be described with reference to FIGS.
In the second embodiment, the first on-off valve 21, the second on-off valve 22, and the intake metering valve 28 are disposed at the downstream end of the first bypass passage 17 with respect to the fuel passage 14, as shown in FIGS. In the point provided in the confluence | merging part 31, it differs greatly from 1st Embodiment. In the following, the second embodiment will be described focusing on this difference. In addition, the same code | symbol is attached | subjected to the member, location, etc. similar to 1st Embodiment, and description is abbreviate | omitted.

  FIG. 5 shows the internal structure of the merging portion 31. The junction 31 employs a configuration in which fuel flows in from two ports (port Pb, port Pc) and flows out from one port (port Pa). Immediately downstream of the intake metering valve 28 corresponds to “port Pa”, immediately upstream of the intake metering valve 28 corresponds to “port Pb”, and the downstream end of the first bypass flow path 17 corresponds to “port Pc”. Equivalent to. The port Pb and the port Pc are located at locations facing each other (upper and lower sides in FIG. 5) in the merging portion 31.

  The first on-off valve 21 and the second on-off valve 22 have a common main valve body 32. The main valve body 32 consists of a cylindrical body with one end (the upper end in FIG. 5) opened. A large-diameter portion 33 having a larger diameter than other portions is formed on the outer periphery of the open end of the main valve body 32. In the large-diameter portion 33, the main valve body 32 is liquid-tight ( It is slidably fitted in the (seal) state. In the peripheral wall portion 32 </ b> A of the main valve body 32, a communication hole 34 is formed at a location corresponding to the port Pa (on the right side in FIG. 5) for communicating the internal space of the main valve body 32 with the port Pa.

  The main valve body 32 can reciprocate between a first opening / closing position shown in FIG. 5 and a second opening / closing position shown in FIGS. 6 (A) and 6 (B). In the first opening / closing position, the main valve body 32 blocks between the port Pb and the port Pa and allows communication between the port Pc and the port Pa. Therefore, the fuel flow path 14 is closed upstream of the intake metering valve 28, and the downstream end of the first bypass flow path 17 is communicated with the fuel flow path 14. In the second opening / closing position, the main valve body 32 communicates between the port Pb and the port Pa and blocks between the port Pc and the port Pa. Therefore, the downstream end of the first bypass channel 17 is blocked from the fuel channel 14, and the fuel channel 14 is opened upstream of the intake metering valve 28. As described above, the main valve body 32 reciprocates between the first opening / closing position and the second opening / closing position, whereby the downstream end of the first bypass passage 17 is communicated with or cut off from the fuel passage 14. The fuel flow path 14 is opened and closed upstream of the intake metering valve 28.

  As shown in FIG. 5, an outer spring 35 serving as a first biasing member that constantly biases the main valve body 32 toward the port Pb is provided in the junction portion 31. The urging direction of the outer spring 35 is a direction in which the downstream end of the first bypass channel 17 communicates with the fuel channel 14 (upward in FIG. 5).

  The intake metering valve 28 includes a sub-valve element 36 disposed in the main valve element 32. The sub-valve body 36 is formed of a cylindrical body with one end (the lower end in FIG. 5) opened, and is slidably fitted to the inner wall surface of the main valve body 32 in a liquid-tight (sealed) state. The sub-valve body 36 is connected to an electromagnetic actuator 37 and is driven to reciprocate by controlling the energization of the solenoid 38 of the electromagnetic actuator 37 by the electronic control device 24 (see FIGS. 1 and 2). An inner spring 39 as a second urging member is provided between the bottom portion 32B of the main valve body 32 and the ceiling portion 36B of the sub-valve body 36. The inner spring 39 causes the main valve body 32 to move to the outer spring. 35 is biased in the opposite direction (downward in FIG. 5).

  A communication hole 41 is formed in the ceiling portion 36 </ b> B of the sub-valve element 36 to communicate the port Pb and the internal space of the sub-valve element 36. Further, in the peripheral wall portion 36A of the sub-valve element 36, a communication hole 42 is opened at a location corresponding to the port Pa (right side in FIG. 5). The positional relationship between the communication hole 42 and the communication hole 34 of the main valve body 32 changes as the sub valve body 36 moves relative to the main valve body 32 in the vertical direction. Along with this, the overlapping amount of both communication holes 42 and 34 also changes, the cross-sectional area of the fuel flow path changes, and the fuel flowing from the port Pb to the port Pa is metered.

  In the fuel supply device 11 of the second embodiment configured as described above, the electronic control device 24 supplies the electromagnetic actuator 37 to the electromagnetic actuator 37 according to the state of the ignition switch 29 (ON / OFF) and the engine load (low load / high load). Is controlled. By this control, the fuel supply device 11 operates as shown in FIG.

<When engine 10 is stopped>
When the engine 10 is stopped (IG: off), the discharge pressure (required discharge pressure) requested by the electronic control device 24 to the fuel supply device 11 is “0”, and the discharge amount (required discharge amount) is “0”. is there. In the merging portion 31, as shown in FIG. 5, the energization to the electromagnetic actuator 37 is stopped, and the sub-valve element 36 is stopped at the uppermost position in the movable range. Further, the main valve element 32 biased upward by the outer spring 35 is stopped at the first opening / closing position.

  By these main valve body 32 and sub valve body 36, the fuel flow path 14 is closed above the intake metering valve 28 (both communication holes 34, 42), and the port Pb and the port Pa are shut off. Further, the port Pc and the port Pa are communicated. In other words, both the port Pa and the port Pc are opened and the port Pb is closed. Since the low pressure pump 15 and the high pressure pump 16 are also stopped along with the stop of the engine 10, the fuel does not flow through the junction 31 (discharge amount: 0). The fuel pressures at the ports Pa, Pb, and Pc are all “0”, and both the required discharge pressure and the required discharge amount are satisfied.

<When engine 10 is started (IG: ON)>
When the engine 10 is started (IG: on), a medium pressure discharge pressure and a large discharge amount are required. At this time, energization to the electromagnetic actuator 37 continues to be stopped, and the state of each part in the merging portion 31 is the same as when the engine 10 is stopped. In the junction part 31, between the port Pb and the port Pa is interrupted | blocked, and between the port Pc and the port Pa is connected. Both the port Pa and the port Pc are opened, and the port Pb is closed.

  The first bypass passage 17 is opened by the communication between the port Pc and the port Pa, and the fuel can flow through the first bypass passage 17. A part of the fuel in the fuel tank 12 is sucked by the operation of the high-pressure pump 16. As a result of this suction, a part of the fuel in the fuel tank 12 is separated from the fuel flow path 14 upstream of the low pressure pump 15 in the process of flowing through the fuel flow path 14 as shown in FIG. It flows into the path 17. After passing through the first bypass flow path 17, the fuel flows into the fuel flow path 14 (merging portion 31) between the low pressure pump 15 and the high pressure pump 16 and downstream of the intake metering valve 28. The fuel is sucked into the high-pressure pump 16 without passing through the intake metering valve 28 and thus without being restricted in passage. For this reason, both the fuel pressures of the port Pc and the port Pa are low. The amount of fuel discharged from the high-pressure pump 16 is smaller than when passing through the low-pressure pump 15 and the high-pressure pump 16 in this order. Further, the pressure of the fuel discharged from the high pressure pump 16 is lower than that in the case of passing through the low pressure pump 15 and the high pressure pump 16 in order. The fuel discharged from the high-pressure pump 16 is sent to the fuel injection valve 13 through the fuel flow path 14.

  Since the port Pb and the port Pa are blocked, the fuel flowing from the downstream end of the first bypass channel 17 to the fuel channel 14 (merging portion 31) is upstream, that is, the main valve body 32. , The internal space of the sub-valve element 36, and thus, does not flow to the port Pb side. Since the fuel discharged from the low pressure pump 15 flows into the port Pb while the port Pb and the port Pa are disconnected, the fuel pressure at the port Pb increases from “low” to “medium”.

  When the engine 10 is started, a part of the fuel in the fuel tank 12 is sucked by the low pressure pump 15. By this suction, the fuel is sucked into the low-pressure pump 15 through the fuel flow path 14, and is discharged after being pressurized. The amount of fuel discharged from the low-pressure pump 15 is larger than when passing through the low-pressure pump 15 and the high-pressure pump 16 in order. Further, the pressure of the fuel discharged from the low pressure pump 15 is lower than that in the case of passing through the low pressure pump 15 and the high pressure pump 16 in order. The fuel discharged from the low-pressure pump 15 flows toward the downstream side of the fuel flow path 14, but in addition to the port Pb being closed, the fuel pressure at the port Pb is “medium” and the third on-off valve Since the valve 23 is opened, the fuel is allowed to flow from the upstream side to the downstream side of the second bypass passage 18. Therefore, the fuel discharged from the low pressure pump 15 flows upstream of the second on-off valve 22 (port Pb), that is, between the low pressure pump 15 and the high pressure pump 16 and separates from the fuel flow path 14 and flows into the second bypass flow path 18. To do. The fuel passes through the second bypass passage 18 and the third on-off valve 23, and then joins the fuel passage 14 downstream of the high-pressure pump 16, and sequentially passes through the first bypass passage 17 and the high-pressure pump 16 described above. It is sent to the fuel injection valve 13 together with the spent fuel.

  Thus, when the engine 10 is started, the amount of fuel pressure is larger in the region where the engine rotational speed is extremely low (very low rotational speed region) than when passing through the low pressure pump 15 and the high pressure pump 16 in order. Low fuel is supplied to the fuel injector 13. Therefore, in the extremely low rotational speed region at the time of starting, more fuel is required than when passing through the low pressure pump 15 and the high pressure pump 16 in order, but this requirement is satisfied. At the same time, although the fuel pressure is not as high as when passing through the low-pressure pump 15 and the high-pressure pump 16 in order, a moderate fuel pressure is required for the ignition of the fuel, this requirement is also satisfied.

<Immediately after starting the engine 10 (at the first explosion)>
At the time of the first combustion (at the first explosion) according to the ON operation of the ignition switch 29, the discharge pressure is switched from “medium” to “high”, and the discharge amount is switched from “many” to “small”. Required. At this time, as shown in FIG. 6A, the sub-valve element 36 is displaced toward the port Pc by energizing the electromagnetic actuator 37, and this displacement is transmitted to the main valve element 32 via the inner spring 39. The outer spring 35 is compressed, and the main valve body 32 is displaced to the port Pc side in conjunction with the auxiliary valve body 36. The closed port Pb is opened by the above displacement, and fuel can flow into the internal spaces of the main and sub valve bodies 32 and 36 from the port Pb. At this time, the communication holes 42 and 34 are somewhat overlapped, that is, “small opening”, and the fuel in the internal space of the main and sub valve bodies 32 and 36 passes through the communication holes 42 and 34. It can flow out to port Pa. In this way, the fuel at the port Pb can flow to the port Pa through the intake metering valve 28 (both communication holes 42 and 34).

  Further, the connection between the port Pc and the port Pa is blocked, and the inflow of fuel from the port Pc, that is, the first bypass flow path 17 to the port Pa becomes impossible. In this way, the opened port Pc is closed, and the fuel flow in the first bypass passage 17 becomes impossible. The suction force of the high-pressure pump 16 does not reach the port Pc, and the fuel pressure at the port Pc is low.

  For this reason, the fuel in the fuel tank 12 is sucked into the low-pressure pump 15 as shown in FIG. A large amount of fuel is discharged from the low pressure pump 15 although the fuel pressure is lower than that of the high pressure pump 16 alone. The fuel pressure at the port Pb is “medium” as when the engine 10 is started (IG: on). The fuel discharged from the low pressure pump 15 is sucked by the high pressure pump 16. Due to this suction, the fuel sequentially passes through the second on-off valve 22 (port Pb) and the suction metering valve 28 (both communication holes 42 and 34). At this time, the passage of fuel is restricted by the intake metering valve 28, and the fuel pressure at the port Pa increases from “low” to “medium”. The fuel is sucked into the high-pressure pump 16 and pressurized. From the high-pressure pump 16, fuel having a fuel pressure (high pressure) higher than that at the time of passing through the low-pressure pump 15 and the intake metering valve 28 is discharged and sent to the fuel injection valve 13.

  In addition, since the fuel pressure of the fuel discharged from the high pressure pump 16 is higher than the pressure of the fuel discharged from the low pressure pump 15, the third on-off valve 23 is closed. By this valve closing, the second bypass flow path 18 is closed, and the fuel flow in the second bypass flow path 18 becomes impossible.

  In this way, when the engine 10 is started (at the time of the first explosion), a small amount of fuel is supplied to the fuel injection valve 13 at a fuel pressure higher than the extremely low rotational speed range when the engine 10 is started (IG: on). Supplied. Therefore, both the above-described required discharge pressure (medium → high) and the required discharge amount (high → low) are satisfied.

<After starting (at low load)>
When the engine 10 is under a low load, a high discharge pressure and a small discharge amount are required. Therefore, the open / closed state and the fuel pressure for the ports Pa, Pb, and Pc are the same as those immediately after the engine 10 is started (at the time of the first explosion). That is, the port Pa is slightly opened, the port Pb is opened, and the port Pc is closed. Each fuel pressure at the port Pa and the port Pb is medium, and the fuel pressure at the port Pc is low.

<After starting (at high load)>
When the engine 10 is under a high load, a high discharge pressure and a medium discharge amount are required. At this time, the state of each part is basically the same as that at the time of the low load described above. The difference is that the sub-valve element 36 is further displaced toward the port Pc while the electromagnetic actuator 37 compresses the inner spring 39 as shown in FIG. Due to this displacement, the sub-valve element 36 moves relative to the main valve element 32, and the amount of overlap between the communication holes 42, 34 increases. The throttle action by the suction metering valve 28 is weakened, and the port Pa is opened largely. The amount of fuel flowing from the port Pb to the port Pa through the intake metering valve 28 (both communication holes 42 and 34) increases, and the demand for the discharge amount (required discharge amount: medium) is satisfied.

<When the ignition switch 29 is turned off>
When the ignition switch 29 is turned off by the driver to stop the engine 10, the discharge pressure is switched from “high” to “0”, and the discharge amount is “low (at low load)” or “medium ( It is required to switch from “at high load” to “0”. In response to the off operation, in the merging portion 31, as shown in FIG. 5, energization to the electromagnetic actuator 37 is stopped and the sub-valve element 36 is displaced to the uppermost position in the movable range. Further, the main valve body 32 is displaced from the second opening / closing position to the first opening / closing position by the urging force of the outer spring 35.

  Due to the displacement of the main valve body 32 and the sub-valve body 36, the port Pb and the port Pa are blocked, and the port Pc and the port Pa are communicated. In other words, both the port Pa and the port Pc are opened and the port Pb is closed. Since the low-pressure pump 15 and the high-pressure pump 16 are stopped when the engine 10 is stopped, the fuel does not flow through the junction 31. The fuel pressures at the ports Pa, Pb, and Pc all decrease to “0”, and both the required discharge pressure (high → 0) and the required discharge amount (0) are satisfied.

Therefore, according to the second embodiment, the following effects can be obtained in addition to the above (1) to (4).
(5) By providing the first on-off valve 21, the second on-off valve 22 and the intake metering valve 28 at the junction 31 at the downstream end of the first bypass passage 17 with respect to the fuel passage 14, these three valves 21 , 22 and 28 are arranged in a state where they are collected in one place. Therefore, it is possible to share parts, and it is possible to reduce the size of the fuel supply device 11 as compared with the case where the valves 21, 22, and 28 are arranged apart from each other.

  (6) A common main valve body 32 is provided for the first on-off valve 21 and the second on-off valve 22, and the main valve body 32 is reciprocated to connect or block between the port Pb and the port Pa. Pc and port Pa are communicated or blocked. In other words, the fuel flow path 14 is opened and closed upstream of the intake metering valve 28, and the downstream end of the first bypass flow path 17 is communicated with or cut off from the fuel flow path 14. As described above, since the fuel flow path 14 and the first bypass flow path 17 are opened and closed by reciprocating the common main valve body 32, compared to the case where the valve bodies are provided for each opening and closing, the parts The score can be reduced.

  (7) The first opening / closing position and the second opening / closing position are set, and the range sandwiched between the both opening / closing positions is the movable range of the main valve element 32. In the first opening / closing position, the fuel flow path 14 is closed upstream of the intake metering valve 28, and the downstream end of the first bypass flow path 17 is communicated with the fuel flow path 14, while the second opening / closing position. Then, the downstream end of the first bypass passage 17 is blocked from the fuel passage 14, and the fuel passage 14 is opened upstream of the intake metering valve 28. Thus, by reciprocating the main valve body 32 between the first opening / closing position and the second opening / closing position, each opening / closing of the first bypass passage 17 and the fuel passage 14 can be performed, and (6) The effect of is obtained with certainty.

  (8) The main valve body 32 is formed in a cylindrical shape, and the communication hole 34 is provided in the peripheral wall portion 32 </ b> A, and the internal space of the main valve body 32 and the communication hole 34 are part of the fuel flow path 14. Further, as a part of the intake metering valve 28, a sub-valve body 36 that reciprocates in the main valve body 32 is provided, and a communication hole 42 is provided in the peripheral wall portion 36A. For this reason, the fuel supplied to the high-pressure pump 16 can be regulated by adjusting the amount of overlap between the two communication holes 42 and 34 by relatively moving the sub-valve element 36 in the main valve element 32.

  (9) The configuration of the suction metering valve generally used in the background art is the same as that in FIG. 5 in which the port Pc and the outer spring 35 are omitted and the main valve body 32 is immovable. This suction metering valve is supplied to the high-pressure pump 16 by displacing the sub-valve element 36 in the main valve element 32 by the electromagnetic actuator 37 and adjusting the overlapping amount of the two communication holes 42 and 34 according to the displacement. The fuel is to be metered.

  In the second embodiment, the basic structure of the suction metering valve 28 in this background art is used, the main valve body 32 can be reciprocated, and the port Pc and the outer spring 35 are added. For this reason, as the suction force of the solenoid 38 in the electromagnetic actuator 37 is increased, the fuel flow path (port Pb → port Pa, port Pc → port Pa) at the junction 31 is switched and the communication holes 42 and 34 are changed. Variable aperture can be performed, and it is easy to follow the metering control in the background art.

(Third embodiment)
Next, a third embodiment embodying the present invention will be described with reference to FIGS. 8 and 9 focusing on differences from the second embodiment.

  In the third embodiment, the lower limit of the movable range of the main valve body 32 is the second opening / closing position as in the second embodiment (see FIGS. 9A and 9B), but the upper limit is not particularly set. . Accordingly, the main valve body 32 itself has a function of communicating or blocking the downstream end of the first bypass flow channel 17 with respect to the fuel flow channel 14 (function of communicating or blocking between the port Pc and the port Pa). It does not have a function of opening and closing the fuel flow path 14 upstream of the quantity valve 28 (function of communicating or blocking between the port Pb and the port Pa).

  In the third embodiment, this latter function is performed by the communication holes 34 and 42 instead of the main valve body 32 itself. For this purpose, the communication holes 34 and 42 are provided at locations satisfying the following conditions (i) and (ii) in the peripheral wall portion 32A of the main valve body 32 and the peripheral wall portion 36A of the auxiliary valve body 36.

Condition (i): In the state where the downstream end of the first bypass passage 17 communicates with the fuel passage 14, both the communication holes 42 and 34 do not overlap each other (see FIG. 8).
Condition (ii): When the downstream end of the first bypass passage 17 is blocked from the fuel passage 14, the sub valve body 36 moves relative to the main valve body 32, so that the two communication holes 42 and 34 are formed. Overlapping each other (see FIG. 9B).

  Furthermore, in the third embodiment, the inner spring 39 having a larger biasing force (set load) than the outer spring 35 is used. The third embodiment is different from the second embodiment in the above points. In addition, the same code | symbol is attached | subjected to the member, location, etc. similar to 2nd Embodiment, and description is abbreviate | omitted.

  The operation of the fuel supply device 11 configured as described above is basically the same as that of the second embodiment. The difference is the action at the time of the first explosion (immediately after the start) according to the ON operation of the ignition switch 29, as will be described next.

<Immediately after starting the engine 10 (at the first explosion)>
At this time, it is required that the discharge pressure is switched from “medium” to “high” and the discharge amount is switched from “high” to “low”. In order to meet this requirement, the discharge pressure can be quickly increased by avoiding a decrease in the fuel pressure at the port Pa due to the displacement of the main and sub valve bodies 32, 36 at the junction 31. is important.

  In this regard, in the third embodiment, when the sub-valve element 36 is displaced from the state shown in FIG. 8 to the port Pc side by energizing the electromagnetic actuator 37, the urging force of the inner spring 39 is changed to the urging force of the outer spring 35. Therefore, the sub-valve body 36, the inner spring 39, and the main valve body 32 are integrally displaced toward the port Pc while compressing the outer spring 35. In this state, the communication holes 42 and 34 do not overlap each other. Therefore, fuel can be circulated from the port Pc to the port Pa, but fuel cannot be circulated from the port Pb to the port Pa.

  When the main valve body 32 comes into contact with the valve seat of the port Pc as shown in FIG. 9A due to the above displacement, the port Pc and the port Pa are blocked, and the fuel cannot flow from the port Pc to the port Pa. It becomes. In this state, the communication holes 42 and 34 are not yet overlapped with each other. Therefore, the fuel cannot be circulated from the port Pb to the port Pa.

  Since the main valve body 32 is restricted from being further displaced to the port Pc side by the above contact, the sub-valve body 36 compresses the inner spring 39 while compressing the port Pc, as shown in FIG. Displace to the side. With this displacement, the communication hole 42 of the sub-valve element 36 approaches the communication hole 34 of the main valve element 32. The communication holes 42 and 34 are overlapped with a slight delay from the disconnection between the port Pc and the port Pa (see FIG. 9A), and the fuel in the internal space of the main and sub valve bodies 32 and 36 is passed through the communication holes. It becomes possible to flow into the port Pa through 42 and 34. That is, the port Pb and the port Pa communicate with each other, and fuel can be distributed from the port Pb to the port Pa. At this time, since the port Pc and the port Pa are blocked as described above, the fuel flowing into the port Pa through both the communication holes 42 and 34 is prevented from leaking to the port Pc side. As described above, the main valve body 32 reliably shuts off the port Pc and the port Pa, and then the communication holes 42 and 34 overlap each other so that the fuel flows into the port Pa from the port Pb. The decrease is avoided, and the discharge pressure of the high-pressure pump 16 is quickly increased. The above-mentioned required discharge pressure (medium → high) is satisfied.

Therefore, according to the third embodiment, in addition to the above (1) to (5), (8), (9), the following effects can be obtained.
(10) A main valve body 32 having a communication hole 34 is provided so as to be able to reciprocate, and a sub-valve body 36 having a communication hole 42 is provided in the main valve body 32 so as to be able to reciprocate. For this reason, the downstream end of the first bypass passage 17 can be communicated with or blocked from the fuel passage 14 by reciprocating the main valve body 32. The fuel flow path 14 can be opened and closed upstream of the intake metering valve 28 by changing the positional relationship between the two communication holes 42 and 34 by relatively moving the sub-valve element 36 within the main valve element 32. Furthermore, fuel can be regulated by adjusting the amount of overlap between the two communication holes 42 and 34 by relatively moving the sub-valve element 36 within the main valve element 32. In this way, by moving the main valve body 32 back and forth and moving the sub valve body 36 relative to the main valve body 32, the first on-off valve 21, the second on-off valve 22 and the intake metering valve 28 are respectively moved. The function of can be demonstrated.

  (11) The two communication holes 34 and 42 are not overlapped with each other in the state where the downstream end of the first bypass passage 17 communicates with the fuel passage 14 with respect to the main valve body 32 and the subvalve body 36. In this state, the sub-valve element 36 is provided at a position where the sub-valve element 36 overlaps with each other by moving relative to the main valve element 32. For this reason, the main valve body 32 is reciprocated and the sub-valve body 36 is moved relative to the main valve body 32 so that the fuel flow path 14 is opened and closed upstream of the intake metering valve 28 and fuel metering is performed. Can be performed reliably.

  (12) By using the inner spring 39 having a larger urging force than the outer spring 35, the main valve body 32 is first brought into contact with the valve seat of the port Pc when the engine 10 is first exploded. Block communication between Pa. In addition, the communication holes 42 and 34 are overlapped with each other to allow fuel to flow from the port Pb to the port Pa. Therefore, it is possible to avoid a decrease in the fuel pressure at the port Pa and to quickly increase the discharge pressure of the high-pressure pump 16.

Note that the present invention can be embodied in another embodiment described below.
As the low-pressure pump 15 in each of the above embodiments, an electric pump may be used instead of the pump driven by the engine 10.

The present invention can be applied not only to a diesel engine but also to a fuel supply device for a gasoline engine.
-In 2nd and 3rd embodiment, while forming the valve seat of the connection part of the port Pc with respect to the confluence | merging part 31 in a taper shape, the outer peripheral surface of the bottom part 32B of the main valve body 32 is formed in a taper shape, and this taper shape The ports Pc and Pa may be blocked by bringing these portions into contact with each other.

  -As the 3rd on-off valve 23, you may use what is opened and closed by electricity supply instead of what was demonstrated in said each embodiment. In this case, the third on-off valve is opened only when the engine 10 is started.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the fuel flow path at the time of engine starting about the fuel supply apparatus concerning 1st Embodiment. 1 is a schematic diagram showing a fuel flow path after engine startup. The schematic which shows the flow path of the fuel at the time of engine starting about the fuel supply apparatus concerning 2nd Embodiment. 1 is a schematic diagram showing a fuel flow path after engine startup. The schematic sectional drawing which shows the internal structure of the confluence | merging part with respect to the fuel flow path of the 1st bypass flow path downstream end. (A), (B) is a schematic sectional drawing explaining operation | movement of each part in a confluence | merging part. Explanatory drawing explaining the state of each part in a confluence | merging part. The schematic sectional drawing which shows the internal structure of the confluence | merging part with respect to the fuel flow path of the 1st bypass flow path downstream end about the fuel supply apparatus concerning 3rd Embodiment. (A), (B) is a schematic sectional drawing explaining operation | movement of each part in a confluence | merging part. The characteristic view which shows the relationship between the rotational speed and discharge amount in a fuel supply apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Diesel engine (internal combustion engine), 11 ... Fuel supply apparatus, 12 ... Fuel tank, 13 ... Fuel injection valve, 14 ... Fuel flow path, 15 ... Low pressure pump, 16 ... High pressure pump, 17 ... 1st bypass flow path, DESCRIPTION OF SYMBOLS 18 ... 2nd bypass flow path, 21 ... 1st on-off valve, 22 ... 2nd on-off valve, 23 ... 3rd on-off valve, 24 ... Electronic control unit, 28 ... Inhalation metering valve, 31 ... Merging part, 32 ... Main Valve body, 34, 41, 42 ... communication hole, 35 ... outer spring (first biasing member), 36 ... sub-valve, 39 ... inner spring (second biasing member).

Claims (22)

In a fuel supply device for an internal combustion engine, in which a low pressure pump and a high pressure pump are provided in a fuel flow path connecting a fuel tank and a fuel injection valve,
The fuel supply device bypasses the low pressure pump and is connected in parallel to the fuel flow path, and the second bypass bypasses the high pressure pump and is connected in parallel to the fuel flow path. The fuel flow path is switched between the flow path and when the engine is started and after the engine is started. When the engine is started, the fuel in the fuel tank passes through the first bypass flow path and the high-pressure pump. A flow path of fuel supplied to the fuel injection valve and supplied to the fuel injection valve via the low pressure pump and the second bypass flow path is formed, and after the engine is started, the fuel in the fuel tank is A switching means for forming a flow path of fuel supplied to the fuel injection valve via the low-pressure pump and the high-pressure pump in order,
The first bypass channel has an upstream end connected to the fuel channel upstream of the low pressure pump, and a downstream end connected to the fuel channel between the low pressure pump and the high pressure pump. Yes,
The upstream end of the second bypass passage is connected to the fuel passage between the downstream end of the first bypass passage and the low pressure pump, and the downstream end of the second bypass passage is downstream of the high pressure pump and the fuel. Connected to the flow path,
The switching means includes a first on-off valve that is provided in the first bypass passage and opens only when the engine is started, and an upstream end of the second bypass passage and the first bypass passage in the fuel passage. A second opening / closing valve provided between the downstream ends and closing only at the time of engine start, and a third opening / closing valve that opens only at the time of engine start and allows the flow of fuel from upstream to downstream of the second bypass passage. With a valve,
The fuel flow path is provided with an intake metering valve that adjusts the amount of fuel drawn into the high-pressure pump by changing the degree of restriction of the passage of fuel between the second on-off valve and the high-pressure pump. Is,
The first on-off valve, the second on-off valve, and the intake metering valve are provided at a junction at a downstream end of the first bypass passage with respect to the fuel passage,
The first on-off valve and the second on-off valve reciprocate a common main valve body to communicate or block the downstream end of the first bypass passage with respect to the fuel passage and to the intake metering valve. Open and close the fuel flow path upstream of
The main valve body has a first open / close position that closes the fuel flow path upstream of the intake metering valve and communicates a downstream end of the first bypass flow path with the fuel flow path; 1 provided so as to be able to reciprocate between a second open / close position that blocks the downstream end of the bypass flow path from the fuel flow path and opens the fuel flow path upstream of the intake metering valve. And is constituted by a cylindrical body having a communication hole, and the internal space of the main valve body and the communication hole are part of the fuel flow path,
The intake metering valve includes a sub-valve element that is provided in the main valve body and moves with respect to the main valve element, and the main valve body and the sub-valve element are moved through relative movement. A fuel supply device for an internal combustion engine, wherein the amount of fuel sucked into the high-pressure pump is adjusted by adjusting the amount of overlap between the communication hole of the valve body and the communication hole of the sub-valve body. In a fuel supply device for an internal combustion engine, in which a low pressure pump and a high pressure pump are provided in a fuel flow path connecting a fuel tank and a fuel injection valve,
The fuel supply device bypasses the low pressure pump and is connected in parallel to the fuel flow path, and the second bypass bypasses the high pressure pump and is connected in parallel to the fuel flow path. The fuel flow path is switched between the flow path and when the engine is started and after the engine is started. When the engine is started, the fuel in the fuel tank passes through the first bypass flow path and the high-pressure pump. A flow path of fuel supplied to the fuel injection valve and supplied to the fuel injection valve via the low pressure pump and the second bypass flow path is formed, and after the engine is started, the fuel in the fuel tank is A switching means for forming a flow path of fuel supplied to the fuel injection valve via the low-pressure pump and the high-pressure pump in order,
The first bypass channel has an upstream end connected to the fuel channel upstream of the low pressure pump, and a downstream end connected to the fuel channel between the low pressure pump and the high pressure pump. Yes,
The upstream end of the second bypass passage is connected to the fuel passage between the downstream end of the first bypass passage and the low pressure pump, and the downstream end of the second bypass passage is downstream of the high pressure pump and the fuel. Connected to the flow path,
The switching means includes a first on-off valve that is provided in the first bypass passage and opens only when the engine is started, and an upstream end of the second bypass passage and the first bypass passage in the fuel passage. A second opening / closing valve provided between the downstream ends and closing only at the time of engine start, and a third opening / closing valve that opens only at the time of engine start and allows the flow of fuel from upstream to downstream of the second bypass passage. With a valve,
The fuel flow path is provided with an intake metering valve that adjusts the amount of fuel drawn into the high-pressure pump by changing the degree of restriction of the passage of fuel between the second on-off valve and the high-pressure pump. Is,
The first on-off valve, the second on-off valve, and the intake metering valve are provided at a junction at a downstream end of the first bypass passage with respect to the fuel passage,
The first on-off valve communicates or blocks the downstream end of the first bypass passage with respect to the fuel passage by reciprocating a main valve body,
The second on-off valve and the intake metering valve include, in addition to the main valve body, a sub-valve body that is provided in the main valve body and moves relative to the main valve body, A communication hole is provided in each of the valve body and the sub-valve body,
The second on-off valve changes the suction metering by changing whether or not the communication hole of the main valve body and the communication hole of the sub valve body are overlapped through relative movement of the main valve body and the sub valve body. Open and close the valve,
The suction metering valve is sucked into the high-pressure pump by adjusting the amount of overlap between the communication hole of the main valve body and the communication hole of the sub-valve body through relative movement of the main valve body and the sub-valve body. A fuel supply device for an internal combustion engine characterized by adjusting the amount of fuel to be produced. The fuel supply apparatus for an internal combustion engine according to claim 2,
When the downstream end of the first bypass passage communicates with the fuel passage, the communication hole of the main valve body and the communication hole of the sub valve body are maintained in a state that does not overlap each other, When the downstream end of the bypass flow path is blocked from the fuel flow path, the communication hole of the main valve body and the communication of the sub valve body according to the positional relationship between the main valve body and the sub valve body A fuel supply device for an internal combustion engine, wherein the holes are maintained in a state where the holes do not overlap each other or in a state where they overlap each other. The fuel supply device for an internal combustion engine according to claim 3,
A first urging member that urges the main valve body in a direction in which a downstream end of the first bypass flow path communicates with the fuel flow path; and is provided between the main valve body and the sub-valve body. And a second urging member that urges the main valve body in a direction opposite to the first urging member. The fuel supply device for an internal combustion engine according to claim 4,
The fuel supply device for an internal combustion engine, wherein an urging force of the second urging member is set larger than an urging force of the first urging member. In the fuel supply device for an internal combustion engine according to any one of claims 1 to 5,
The fuel supply device for an internal combustion engine, wherein the intake metering valve is provided upstream of the downstream end of the first bypass flow path. The fuel supply apparatus for an internal combustion engine according to any one of claims 1 to 6,
The fuel supply device for an internal combustion engine, wherein the intake metering valve is a throttle valve that varies a cross-sectional area of the fuel flow path. A fuel tank for storing fuel, a fuel injection valve for injecting fuel, a fuel flow path connecting the fuel tank and the fuel injection valve, and a low pressure pump and a high pressure pump provided in the fuel flow path for pressurizing the fuel In a fuel supply device for an internal combustion engine,
The fuel supply device further includes switching means for switching the fuel flow path in the fuel path to a different one between when the engine is started and after the engine is started,
The switching means includes a first flow path through which fuel flows from the fuel tank to the fuel injection valve only through the low-pressure pump of the low-pressure pump and the high-pressure pump when the engine is started, and the fuel is the low-pressure pump. A second flow path that flows from the fuel tank to the fuel injection valve via only the high-pressure pump among the pump and the high-pressure pump, and after the engine is started, fuel is supplied to the low-pressure pump and the high-pressure pump. A fuel supply device for an internal combustion engine, characterized by forming a third flow path that passes through these pumps in this order and flows from the fuel tank to the fuel injection valve. The fuel supply device for an internal combustion engine according to claim 8,
The fuel supply device further includes an intake metering valve that is provided between the low-pressure pump and the high-pressure pump and adjusts a flow rate of fuel discharged from the low-pressure pump and flowing into the high-pressure pump,
The switching means forms, as the third flow path, a path through which fuel flows in the order of the low-pressure pump, the suction amount metering valve, and the high-pressure pump. apparatus. The fuel supply device for an internal combustion engine according to claim 8 or 9,
The fuel flow path includes a first flow path connecting the fuel tank and the inlet of the low pressure pump, a second flow path connecting the outlet of the low pressure pump and the inlet of the high pressure pump, and the high pressure pump. A third flow path connecting the outlet and the fuel injection valve; a low pressure bypass flow path bypassing the low pressure pump and connecting the first flow path and the second flow path; and bypassing the high pressure pump A portion of the second flow path that connects the second flow path and the third flow path and that is closer to the low pressure pump than a connection portion of the low pressure bypass flow path with respect to the second flow path. Including a high-pressure bypass channel connecting the third channel,
The switching means switches the open / closed states of the second flow path, the low pressure bypass flow path, and the high pressure bypass flow path, so that the first flow path and the second flow path are used as fuel flow paths when the engine is started. A fuel supply device for an internal combustion engine, characterized in that a third flow path is formed as a fuel flow path after the engine is started. The fuel supply device for an internal combustion engine according to claim 10,
The switching means forms, as the first flow path, a path through which fuel flows in the order of the first flow path, the low pressure pump, the high pressure bypass flow path, and the third flow path, and the second flow path. As a path, a path through which fuel flows in the order of the first flow path, the low pressure bypass flow path, the second flow path, the high pressure pump, and the third flow path is formed, and the third flow path, A fuel supply device for an internal combustion engine, characterized in that a path through which fuel flows is formed in the order of the first flow path, the second flow path, and the third flow path. The fuel supply device for an internal combustion engine according to claim 10 or 11,
The switching means uses a portion between the branch point of the high-pressure bypass channel and the branch point of the low-pressure bypass channel in the second channel as an inter-branch channel when the engine is started. The low-pressure bypass flow path and the high-pressure bypass flow path are opened and the branch-flow path is closed to form the first flow path and the second flow path, and the low-pressure bypass flow after the engine is started. A fuel supply device for an internal combustion engine, wherein the third flow path is formed by closing a passage and the high-pressure bypass flow path and opening the flow path between the branch points. The fuel supply device for an internal combustion engine according to claim 8 or 9,
The fuel flow path includes a first common flow path whose inlet is connected to the fuel tank and branches into two passages at the outlet, and an outlet connected to the fuel injection valve and the two passages merge at the inlet. Connecting a second common flow path, a first branch flow path connecting the outlet of the first common flow path and the inlet of the low pressure pump, and connecting the outlet of the low pressure pump and the inlet of the second common flow path A second branch channel, a third branch channel connecting the outlet of the first supply channel and the inlet of the high pressure pump, and an outlet of the high pressure pump and the inlet of the second supply channel are connected. Comprising a fourth branch flow path, and an intermediate branch flow path connecting the second branch flow path and the third branch flow path,
The switching means includes a communication state of the first common flow channel with respect to the third branch flow channel, a communication state of the intermediate branch flow channel with respect to the third branch flow channel, and the second with respect to the second common flow channel. By switching the communication state of the branch flow path, the first flow path and the second flow path are formed as the fuel flow path when the engine is started, and the third flow path is used as the fuel flow path after the engine is started. A fuel supply device for an internal combustion engine characterized by comprising: The fuel supply device for an internal combustion engine according to claim 13,
The switching means causes the fuel to flow in the order of the first common flow path, the first branch flow path, the low pressure pump, the second branch flow path, and the second common flow path as the first flow path. A path is formed, and fuel is circulated in the order of the first common flow path, the third branch flow path, the high-pressure pump, the fourth branch flow path, and the second common flow path as the second flow path. A first common flow path, the first branch flow path, the low pressure pump, the second branch flow path, the intermediate branch flow path, and the third branch flow path. And a fuel supply device for an internal combustion engine, wherein a passage through which fuel flows is formed in the order of the high-pressure pump, the fourth branch passage, and the second common passage. The fuel supply device for an internal combustion engine according to claim 13 or 14,
The switching means has a third branch flow channel upstream portion from an outlet of the first common flow channel to a connection portion with the intermediate branch flow channel in the third branch flow channel, and the intermediate in the third branch flow channel. Communication from the connection part with the branch flow path to the inlet of the high-pressure pump as the third branch flow path downstream part with the third branch flow path upstream part, the third branch flow path downstream part, and the intermediate branch flow path And the communication state between the second branch flow path and the second common flow path, and when the engine is started, the upstream portion of the third branch flow path and the third branch flow path Communicating with the downstream portion, blocking between the third branch channel and the intermediate branch channel, and communicating between the second branch channel and the second common channel. To form the first distribution path and the second distribution path, and after the engine is started, the third distribution path Blocking between the upstream portion of the flow path and the downstream portion of the third branch flow path, communicating between the intermediate branch flow path and the downstream portion of the third branch flow path, and the second branch flow path The fuel supply device for an internal combustion engine, wherein the third flow path is formed by blocking between the second common flow path. The fuel supply device for an internal combustion engine according to claim 15,
The switching means includes a port A to which the downstream portion of the third branch channel is connected, a port B to which the intermediate branch channel is connected, and a port C to which the upstream portion of the third branch channel is connected, and these ports And a valve body that switches a communication state between the ports by movement relative to the port A. When the valve body is in the first open / close position, the port A communicates with the port C and the port A And the port B, thereby communicating between the third branch channel upstream portion and the third branch channel downstream portion, and the third branch channel and the intermediate branch channel. Between the port A and the port C and communicating between the port A and the port B when the valve body is in the second open / close position, As a result, the third branch channel upstream portion and the third branch The fuel supply apparatus for an internal combustion engine, characterized in that in which communicating between said intermediate branch flow path and the third branch flow channel downstream portion with interrupting the connection between the flow path downstream portion.   The fuel supply device for an internal combustion engine according to claim 15,
  The switching means includes a port A to which the downstream portion of the third branch channel is connected, a port B to which the intermediate branch channel is connected, and a port C to which the upstream portion of the third branch channel is connected, and these ports Further comprising a valve body and an auxiliary valve body for switching the communication state between the ports by movement with respect to the port, wherein the valve body is in the first opening / closing position and the auxiliary valve body is in the first adjustment position, The port A and the port C communicate with each other, and the port A and the port B are blocked from each other, whereby the third branch channel upstream portion and the third branch channel downstream portion are connected. Is connected to the third branch flow path and the intermediate branch flow path, the valve body is in the second opening / closing position and the auxiliary valve body is in the second adjustment position. Block between port A and port C In addition, the port A and the port B communicate with each other, thereby blocking between the upstream portion of the third branch channel and the downstream portion of the third branch channel, and the intermediate branch channel and the third It communicates with the downstream of the branch channel
  A fuel supply device for an internal combustion engine.   The fuel supply device for an internal combustion engine according to claim 17,
  The switching means shuts off between the port A and the port C and the port A when the valve body is in the second opening / closing position and the auxiliary valve body is in the first opening / closing position. And the port B, thereby blocking between the third branch flow path upstream portion and the third branch flow path downstream portion, and the third branch flow path and the intermediate branch flow path, Is to block between
  A fuel supply device for an internal combustion engine.   A fuel tank for storing fuel, a fuel injection valve for injecting fuel, a fuel flow path connecting the fuel tank and the fuel injection valve, and a low pressure pump and a high pressure pump provided in the fuel flow path for pressurizing the fuel In a fuel supply device for an internal combustion engine,
  The fuel supply device further includes switching means for switching the fuel flow path in the fuel path to a different one between when the engine is started and after the engine is started,
  The switching means includes a first flow path through which fuel flows from the fuel tank to the fuel injection valve only through the low-pressure pump of the low-pressure pump and the high-pressure pump when the engine is started, and the fuel is the low-pressure pump. A second flow path that flows from the fuel tank to the fuel injection valve via only the high-pressure pump among the pump and the high-pressure pump, and after the engine is started, fuel is supplied to the low-pressure pump and the high-pressure pump. A third flow path that passes through these pumps in this order and flows from the fuel tank to the fuel injection valve,
  The fuel flow path includes a first common flow path whose inlet is connected to the fuel tank and branches into two passages at the outlet, and an outlet connected to the fuel injection valve and the two passages merge at the inlet. Connecting a second common flow path, a first branch flow path connecting the outlet of the first common flow path and the inlet of the low pressure pump, and connecting the outlet of the low pressure pump and the inlet of the second common flow path A second branch channel, a third branch channel connecting the outlet of the first supply channel and the inlet of the high pressure pump, and an outlet of the high pressure pump and the inlet of the second supply channel are connected. Comprising a fourth branch flow path, an intermediate branch flow path connecting the second branch flow path and the third branch flow path,
  The switching means includes a communication state of the first common flow channel with respect to the third branch flow channel, a communication state of the intermediate branch flow channel with respect to the third branch flow channel, and the second with respect to the second common flow channel. By switching the communication state of the branch flow path, the first flow path and the second flow path are formed as a fuel flow path when the engine is started, and the third flow path is used as a fuel flow path after the engine is started. That form
  The switching means has a third branch flow channel upstream portion from an outlet of the first common flow channel to a connection portion with the intermediate branch flow channel in the third branch flow channel, and the intermediate in the third branch flow channel. Communication from the connection part with the branch flow path to the inlet of the high-pressure pump as the third branch flow path downstream part with the third branch flow path upstream part, the third branch flow path downstream part, and the intermediate branch flow path And the communication state between the second branch flow path and the second common flow path, and when the engine is started, the upstream portion of the third branch flow path and the third branch flow path Communicating with the downstream portion, blocking between the third branch channel and the intermediate branch channel, and communicating between the second branch channel and the second common channel. To form the first distribution path and the second distribution path, and after the engine is started, the third distribution path Blocking between the upstream portion of the flow path and the downstream portion of the third branch flow path, communicating between the intermediate branch flow path and the downstream portion of the third branch flow path, and the second branch flow path The third flow path is formed by blocking between the second common flow path,
  The switching means includes a port A to which the downstream portion of the third branch channel is connected, a port B to which the intermediate branch channel is connected, and a port C to which the upstream portion of the third branch channel is connected, and these ports And a valve body that switches a communication state between the ports by movement relative to the port A. When the valve body is in the first open / close position, the port A communicates with the port C and the port A And the port B, thereby communicating between the third branch channel upstream portion and the third branch channel downstream portion, and the third branch channel and the intermediate branch channel. Between the port A and the port C and communicating between the port A and the port B when the valve body is in the second open / close position, As a result, the third branch channel upstream portion and the third branch Is intended to communicating between said intermediate branch flow path and the third branch flow channel downstream portion with interrupting the connection between the flow path downstream portion,
  The switching means causes fuel to flow from the port B to the port A through a valve body passage provided in the valve body when the valve body is in the second opening / closing position. The intake metering valve is configured to adjust the flow rate of the fuel flowing from the port B to the port A by changing the opening area of the valve.
  A fuel supply device for an internal combustion engine.   The fuel supply device for an internal combustion engine according to claim 19,
  The switching means further includes an auxiliary valve body that is provided on the inlet side of the valve body passage and changes an opening area of the inlet of the valve body passage by moving with respect to the valve body.
  A fuel supply device for an internal combustion engine.   The fuel supply device for an internal combustion engine according to claim 20,
  The switching means closes a part of the inlet of the valve body passage by the auxiliary valve body when the valve body is in the second opening / closing position and the auxiliary valve body is in the first adjustment position. And when the valve body is in the second opening / closing position and the auxiliary valve body is in the second adjustment position, the inlet of the valve body passage is opened from the auxiliary valve body.
  A fuel supply device for an internal combustion engine.   The fuel supply device for an internal combustion engine according to any one of claims 19 to 21,
  The switching means adjusts a flow rate between ports, which is a flow rate of fuel flowing from the port B to the port A, by changing an opening area of the valve body passage based on an engine operating state after the engine is started. And the inter-port flow rate is set to the first flow rate on the small flow rate side based on the engine operation state being a low load operation state, and the inter-port flow based on the engine operation state being a high load operation state. The flow rate is set to the second flow rate on the large flow rate side.
  A fuel supply device for an internal combustion engine.

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