JP3172607U - Apparatus for regulating pressure / flow in an internal combustion engine fuel injector - Google Patents

Abstract

An apparatus is provided for optimizing storage volume pressure regulation to improve the efficiency of an injection system.
The injection system 1 defines a storage volume 6 of pressurized fuel supplied by a high-pressure pump 7 along a delivery pipe 8 and a required fuel pressure of the storage volume 6 as a function of the operating state of the engine 2. And a control device 16 for. The adjusting device includes a bypass solenoid valve 14 and a pair of check valves 32 and 33 connected in antiparallel and disposed between the bypass valve 14 and the storage volume 6. When the control device 16 determines a predetermined drop Δp in the fuel pressure of the storage volume 6, one of the check valves 32, 33 enables fuel discharge from the storage volume 6 to the bypass valve 14.
[Selection] Figure 1

Description

  The present invention provides a pressure / pressure in an internal combustion engine fuel injector comprising a pressurized fuel storage volume supplied by a high pressure pump along a delivery pipe to optimize system control. It relates to a device for regulating the flow.

  As is known, in modern internal combustion engines, the high-pressure pump is a common rail that has a predetermined storage volume for supplying many injectors associated with the engine cylinder. Supply fuel to (rail). In order for the fuel to mist properly, it must be brought to ultra-high pressures at about 1600 bar at maximum engine load. Also, the required common rail fuel pressure is usually determined by the electronic controller as a function of engine operating conditions.

  A drain solenoid valve directly connected to the common rail is used to control the drain when the actual pressure on the common rail is higher than what is required to discharge excess fuel to the fuel tank. An injection system opened by is known. When the required fuel pressure suddenly drops due to the operating state of the engine, for example when the vehicle is stopped immediately after driving at high engine speed, the drain solenoid valve will allow sufficient fuel pressure in the common rail. Can't adapt quickly. As a result, the engine is supplied with fuel at a pressure higher than the required pressure, increasing the emission noise.

  A pressure regulator with a bypass solenoid valve fitted to the delivery pipe of the pump, controlled by the controller so that the freshly pumped fuel is discharged directly to the tank before it reaches the common rail Is also known. Such a device comprises a valve means, possibly controlled by a control device, in order to discharge the extra fuel in the common rail directly to the tank if the required fuel pressure suddenly drops.

  In the above case, since the flow of the high pressure pump is usually dependent on the rotational speed of the drive shaft, the pump is usually designed to provide the maximum flow and pressure required in various engine operating conditions. As a result, in certain operating conditions, for example, at maximum speed but at the minimum fuel flow required by the engine, the pump flow is excessive and the excess fuel is drained by a common rail drain solenoid valve or bypass. It is simply discharged into the tank by a solenoid valve. Thus, the known adjusting device has the disadvantage of consuming part of the compression work of the high-pressure pump in the form of heat.

  The object of the present invention is to provide an apparatus for optimizing the storage volume pressure regulation to improve the efficiency of the injection system.

  According to the invention, this object is achieved by supplying a storage volume of pressurized fuel along the delivery pipe by means of a high-pressure pump, and the required fuel pressure of the storage volume is controlled by the controller by a function of the engine operating state. This is achieved by an adjusting device for adjusting the pressure / flow in the fuel injection device of the internal combustion engine. The adjusting device includes a bypass solenoid valve that is fitted to the delivery pipe and controlled by the controller to discharge excess fuel pumped by the pump to the tank, and the controller controls the storage volume. in order to quickly drain excess fuel from the storage volume by the bypass solenoid valve when forming a predetermined drop in the required fuel pressure in the volume) It is characterized by being provided between.

  When adjusting the pressure / flow, as long as the pressure difference on one side of the valve means exceeds a predetermined value, the valve means allows fuel flow from the storage volume to the bypass solenoid valve.

  When adjusting the pressure / flow, only a portion of the fuel in the storage volume is discharged into the tank. As a result, not all work performed on the fuel by the pump is consumed in the form of heat.

It is a figure explaining the fuel-injection apparatus of the internal combustion engine which features the pressurized fuel pressure adjustment apparatus based on this invention.

  Preferred but non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings. The accompanying drawings show a diagram of an internal combustion engine fuel injection device featuring a pressurized fuel pressure regulator according to the present invention.

  Reference numeral 1 in the accompanying drawings indicates a fuel injection device for a common rail of an internal combustion engine 2 (for example, a 4-stroke diesel engine) as a whole. The engine 2 includes many cylinders 3, for example. The cylinder 3 cooperates with each piston (not shown) operable to rotate the drive shaft 4.

  The injection system 1 includes a number of electrical injectors 5 associated with the cylinder 3 for injecting high pressure fuel into the cylinder 3. The injector 5 is connected to the storage volume. The storage volume has a predetermined volume for one or more injectors 5. In the embodiment shown, the storage volume is formed by the usual common rail 6 (all injectors 5 are connected to it).

  High-pressure fuel from a high-pressure pump indicated as a whole by 7 is supplied along a delivery pipe 8 to a common rail 6. The high-pressure pump 7 is supplied in turn by a low-pressure pump (eg, a motor-driven pump 9) along the intake pipe 10 of the pump 7. The motor-driven pump 9 is supplied to the fuel tank 11. The fuel tank 11 is usually accommodated for discharging excess fuel from the injection system 1 and connected to a drain pipe 12 for supplying drain fuel from the injector 5 to the tank 11.

  In order to control the fuel pressure in the common rail 6, the bypass solenoid valve 14 was also normally taken by the injector 5 along the corresponding drain pipe 13 to maintain the required pressure in the common rail 6 ( In order to supply any fuel more than the drawn) to the tank 11, it is placed between the high pressure pump 7 and the common rail 6.

  The fuel in the tank 11 is under atmospheric pressure. In actual use, the motor driven pump 9 compresses low pressure fuel, for example, at about 2 to 5 bars. The high pressure pump 7 compresses the incoming fuel along the intake pipe 10 to supply high pressure fuel along the high pressure pipe 8 to the common rail 6 at, for example, about 1600 bars. Each injector 5 injects an amount of fuel in a range between a minimum value and a maximum value into each cylinder 3 under the control of the electronic control device 16. The electronic control unit 16 may be formed by a normal microprocessor control unit of the engine 2.

  The control device 16 controls the operating state of the engine 2 such as the accelerator pedal position and the rotational speed of the drive shaft 4 detected by corresponding sensors (not shown) and the fuel pressure in the common rail 6 detected by the pressure sensor 17. Accept the signal shown. By processing the received signal with an appropriate program, the control device 16 controls when and how long the injector 5 operates as well as the opening and closing of the solenoid valve 14.

  The high-pressure pump 7 includes one or more reciprocating pumping members 18. Each pumping member 18 is formed by a cylinder 19 having a compression chamber 20 in which a piston 21 slides. Each compression chamber 20 communicates with the intake pipe 10 by a suction valve 25 and communicates with the delivery pipe 8 by a discharge valve 30.

  The piston 21 is moved back and forth to perform an intake stroke and a compression or discharge stroke by an eccentric cam means 22 fitted to a shaft 23 that drives the pump 7. In the described embodiment, two coaxially opposed pumping members 18 are provided and actuated by a single eccentric cam 22. The shaft 23 is connected to the drive shaft 4 by a transmission device 26. As a result, in the embodiment shown, the device 26 commands a compression stroke of one piston 21 for injection by each injector 5 into each cylinder 3 of the engine 2.

  According to the present invention, the fuel injection device 1 includes a device for adjusting the pressure in the common rail 6 in addition to the bypass solenoid valve 14, and includes a valve means indicated by 31 as a whole. The valve means 31 is located between the bypass solenoid valve 14 and the common rail 6, and is provided for quickly discharging excess fuel from the common rail 6 to the delivery pipe 8 with the bypass solenoid valve 14. . More specifically, when the control device 16 forms a predetermined sudden drop in the required fuel pressure in the common rail 6, the valve means 31 is shared between the pump 7 and the bypass solenoid valve 14. Two non-return valves 32, 33, which are provided to drain excess fuel from the rail 6 into the delivery pipe 8 and are connected in antiparallel, for example balls Provide a valve. More specifically, as long as the actual fuel pressure in the common rail 6 is lower than that in the delivery pipe 8 of the pump 7, the pair of first check valves 32 allow the fuel to flow from the pump 7 to the common rail 6. enable. The pair of second check valves 33 is disposed along the pipe 34. The pipe 34 communicates with the delivery pipe 8 at a point 35 upstream from the check valve 32 and at a point 36 downstream from the check valve 32.

  The check valve 33 allows the fuel from the common rail 6 to the solenoid valve 14 to be discharged. Therefore, the two check valves 32 and 33 are connected in antiparallel. Both check valves 32, 33 are preferably of the ball type, and the second check valve 33 has an additional spring 37 with a force corresponding to a predetermined pressure drop or threshold value Δp. Except for, it is substantially similar. Therefore, the difference between the actual fuel pressure at the common rail 6 and the actual fuel pressure determined by the bypass solenoid valve 14 at the delivery pipe 8 of the pump 7 is the threshold at the outlet of the two discharge valves 30. A spring 37 allows the valve 33 to simply open when the value Δp is exceeded.

  Preferably, the threshold value Δp will be set in the region of 1000 bar. Such a pressure drop will occur when the engine 2 operates suddenly at a low load (eg, neutral state) after the engine 2 has been operated at a high load for a predetermined time. In that case, the control device 16 forms a low fuel pressure in the common rail 6 so as to be the best for the operation of the engine 2, ie for the control of the injectors 5. ) Valve 33 opens to quickly reduce the pressure. Fuel consumption and exhaust gas pollutants are greatly reduced. Also, not all pressurized fuel is discharged into the tank 11 (which is at atmospheric pressure), so work already done by the pump 7 is not dissipated or converted to heat.

  The advantages of the fuel pressure adjusting device according to the present invention compared to known techniques will become clear from the foregoing description. In particular, in the case of a sudden pressure drop at the optimum pressure, as formed by the operating state of the engine 2, the fuel pressure in the common rail 6 dissipates the work already pumped. Adapt quickly without reducing energy consumption.

  Obviously, the adjustment device as described herein can be modified without departing from the scope of the appended utility model registration claims. For example, the transmission device 26 and the shaft 23 of the high-pressure pump 7 operated at a speed unrelated to that of the drive shaft 4 may be removed. The high-pressure pump 7 may be formed by two parallel pumping members 18 so as to face each other coaxially. The pump 7 may include other than the two pumping members. Further, the valve means 31, the bypass electromagnetic valve 14, and the delivery pipe 8 may be integrated into the body of the high-pressure pump 7.

DESCRIPTION OF SYMBOLS 1 Fuel injection apparatus 2 Engine 3 Cylinder 6 Rail 7 Pump 8 Delivery pipe 11 Tank 14 Bypass solenoid valve 16 Control apparatus 18 Pumping member 20 Compression chamber 22 Eccentric cam 23 Shaft 31 Valve means 32 First check valve 33 Second check valve 34 Pipe 37 Spring

Claims (7)

An adjusting device for adjusting pressure / flow in a fuel injection device of an internal combustion engine, wherein a storage volume (6) of pressurized fuel is supplied along a delivery pipe (8) by a high-pressure pump (7), and the storage volume The required fuel pressure of (6) is determined by the control device (16) as a function of the operating state of the engine (2),
The adjusting device fits to the delivery pipe (8) and bypass electromagnetic controlled by the control device (16) to discharge excess fuel pumped by the pump (7) to the tank (11). With a valve (14),
Excess fuel from the storage volume (6) to the bypass solenoid valve (14) when the control device (16) forms a predetermined rapid drop (Δp) in the required fuel pressure of the storage volume (6) In order to expedite discharge, valve means (31) is provided between the bypass solenoid valve (14) and the storage volume (6).   The said valve | bulb means (31) discharges | emits the said excess fuel to the said delivery pipe (8) between the said pump (7) and the said bypass solenoid valve (14). Equipment.   3. A device according to claim 2, characterized in that the valve means (31) comprises a pair of check valves (32, 33) connected in antiparallel.   The pair of check valves (32, 33) includes a first check valve (32) that enables fuel flow from the pump (7) to the storage volume (6), and the storage volume (6) to Device according to any of claims 2 or 3, characterized in that the delivery pipe (8) comprises a second check valve (33) enabling fuel discharge. The pump (7) has a suction valve (25) communicating with the intake pipe (10), and a discharge valve (30) communicating with the delivery pipe (8),
The second check valve (33) opens according to a predetermined pressure difference (Δp) between the fuel pressure in the storage volume (6) and the fuel pressure at the outlet of the discharge valve (30). The apparatus of claim 4.   6. Device according to claim 5, characterized in that the second check valve (33) is loaded by an additional spring (37) with a force corresponding to the pressure difference (Δp).   The valve means (31), the bypass electromagnetic valve (14), and the delivery pipe (8) are integrated with a body of the pump (7), according to any one of claims 1 to 6. The device according to one.

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