CN210118216U - Fuel injection system for vehicle and vehicle - Google Patents

Fuel injection system for vehicle and vehicle Download PDF

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Publication number
CN210118216U
CN210118216U CN201920910194.7U CN201920910194U CN210118216U CN 210118216 U CN210118216 U CN 210118216U CN 201920910194 U CN201920910194 U CN 201920910194U CN 210118216 U CN210118216 U CN 210118216U
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fuel
pressure pump
injection system
fuel injection
low
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刘京广
田威
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Robert Bosch GmbH
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Robert Bosch GmbH
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Abstract

The present application provides a fuel injection system for a vehicle, comprising a low-pressure pump, a high-pressure pump, an oil inlet line in fluid communication with a fuel inlet of the low-pressure pump, and an intermediate line fluidly communicating a fuel outlet of the low-pressure pump with a fuel inlet of the high-pressure pump, wherein the fuel injection system further comprises a start assist module comprising a control valve, an accumulator, and a safety valve, the control valve includes a first fuel port and a second fuel port, and has an off position and an on position, wherein the first fuel port is in fluid communication with the intermediate line at a location downstream of a fuel outlet of the low pressure pump, the second fuel port is in fluid communication with the accumulator and with the oil inlet line at a location upstream of a fuel inlet of the low pressure pump via the relief valve, the accumulator having a preset maximum pressure. The application also relates to a vehicle comprising the fuel injection system.

Description

Fuel injection system for vehicle and vehicle
Technical Field
The present application relates to a fuel injection system for a vehicle and a vehicle comprising such a fuel injection system.
Background
Currently, fuel (e.g., diesel) injection systems for vehicles generally include a low pressure portion and a high pressure portion. The fuel is first drawn into the low-pressure portion, pre-pressurized to a certain pressure, and then supplied to the high-pressure portion, where the pre-pressurized fuel is further pressurized to a predetermined higher pressure, then supplied to a common rail portion of a fuel injection system, and finally injected into an engine of a vehicle via an injector.
However, it has been found that starting of the engine may be delayed or malfunction when replacing components in the system, such as filters or pipes, or after a long period of vehicle standstill (a night after shutdown), which is particularly problematic in work or farm machinery applications. The reasons for this problem may be: the presence of air in the low-pressure portion, such as in the aforementioned case, which may enter the low-pressure portion through poorly sealed connectors and return lines and accumulate in the intake line and in the filter on the intake line; or the oil level in the vehicle oil tank is lower than the oil absorption point of the oil inlet pipeline; or when the engine works under the working condition of high altitude, the viscosity of the fuel is higher, or the required oil inlet pressure of the low-pressure pump cannot be achieved due to other reasons; or the user may not deflate the associated tubing as correctly specified.
Therefore, it is necessary to perform an operation of discharging air in the system before the engine is started. A common way of deflating is to manually press a hand pump arranged upstream of the low pressure pump. The hand pump is a mechanical pump, and is relatively laborious and inconvenient to operate.
The provision of an electric transfer pump upstream of the low pressure pump can reduce the air build up in the low pressure part of the system and can assist in starting in cold conditions or high altitude conditions. However, the outlet pressure of the electric transfer pump may exceed the allowable range of the inlet pressure of the low pressure pump at engine start, which may, on the one hand, affect or shorten the service life of the low pressure pump and associated components, and on the other hand, may cause excessive fuel to enter the high pressure pump, resulting in a loss of rail pressure after engine start. Further, the addition of the electric oil feed pump leads to a large cost increase.
It is desirable to solve the above technical problems.
SUMMERY OF THE UTILITY MODEL
The object of the utility model is to discharge the air in the fuel injection system, especially in the low pressure part fast and then promote the startability of engine.
To this end, the present invention provides a fuel injection system for a vehicle comprising a low pressure pump, a high pressure pump, an inlet line in fluid communication with a fuel inlet of the low pressure pump, and an intermediate line in fluid communication with a fuel inlet of the high pressure pump for the fuel outlet of the low pressure pump. The fuel injection system further includes a start assist module including a control valve including a first fuel port and a second fuel port, the first fuel port being in fluid communication with the intermediate line at a location downstream of the low pressure pump, an accumulator, and a relief valve, the control valve having an off position fluidly disconnecting the first fuel port and the second fuel port when de-energized, and an on position fluidly communicating the first fuel port and the second fuel port when energized, the second fuel port being in fluid communication with the accumulator and the intake line via the relief valve at a location upstream of the low pressure pump.
In one embodiment, the control valve may be a solenoid valve, such as a pilot solenoid flow valve. The safety valve may be a one-way valve or a check valve. The accumulator may have a preset maximum pressure.
In one embodiment, the fuel injection system may further comprise any one or more of: the hand pump and the filter are arranged on the oil inlet pipeline; a deflation screw arranged on the intermediate pipeline; a metering unit arranged on the intermediate line between the low-pressure pump and the high-pressure pump; a zero transfer valve having a first fuel port in fluid communication with the intermediate line at a location between the metering unit and the high pressure pump and a second fuel port connected to the inlet line at a location upstream of the low pressure pump.
The utility model also provides a vehicle of including above-mentioned fuel injection system.
According to the fuel injection system, the starting auxiliary module is arranged, so that the aim of quickly exhausting air in a low-pressure part of the system is fulfilled on the one hand, and the starting performance can be improved in the subsequent starting process of the engine on the other hand, particularly after system components are replaced or the engine is stopped for a long time. The required cost is reduced compared to providing an electric fuel delivery pump. And a safety valve is arranged in the starting auxiliary module, so that the service life and the reliability of the pump or the whole system are improved.
Drawings
FIG. 1 is a simplified block diagram of a fuel injection system according to the present invention;
fig. 2 is a partial enlarged view of the rectangular area in fig. 1.
Detailed Description
The fuel injection system of the present application solves the above technical problem by providing a start assist module, which is described in detail below with reference to the accompanying drawings.
The fuel injection system of the present application may be a high pressure common rail system for a vehicle, and particularly, the fuel injection system of the present application may be applied to a construction machine or an agricultural machine.
As shown in fig. 1, the fuel injection system mainly includes a low pressure portion including the low pressure pump 12, a high pressure portion including the high pressure pump 22, a common rail portion 40 storing high pressure fuel from the high pressure portion, and an injection portion injecting the stored high pressure fuel. Optionally, the fuel injection system of the present application may further include a fuel accumulator 10. The fuel injection system may include an oil feed line L1 through which fuel from the fuel reservoir 10 flows into the low pressure pump 12 and an intermediate line L2 fluidly communicating the low pressure pump 12 and the high pressure pump 22.
Generally, fuel is drawn from a fuel accumulator 10, through an oil feed line L1, through a filter 14 provided on an oil feed line L1, into a low-pressure pump 12, and is pre-pressurized at the low-pressure pump 12. The pre-pressurized fuel is discharged from the low-pressure pump 12 via an intermediate line L2, via a metering unit 16 provided on an intermediate line L2, into the high-pressure pump 22, where the fuel is further pressurized to a predetermined high pressure. Fuel having a predetermined high pressure is supplied to the common rail portion 40 and is finally injected into an engine (not shown) of a vehicle via an injector (not shown). The terms "upstream" and "downstream" in this application are defined with respect to the direction D of flow of the fuel in the process.
Also shown in fig. 1 is a zero delivery valve 15 that prevents a little fuel from the metering unit 16 from entering the high-pressure pump 22 when the low-pressure pump 12 is deactivated, and a spill valve 17 that prevents an excess of fuel from being supplied to the high-pressure pump 22 via the metering unit 16 when the outlet pressure of the low-pressure pump 12 is too high. In the illustration, the first fuel port of the spill valve 17 and the first fuel port of the zero delivery valve 15 are connected to the intermediate line L2 at positions upstream and downstream of the metering unit 16, respectively, and the second fuel port of the spill valve 17 and the second fuel port of the zero delivery valve 15 are both connected to the oil feed line L1 at positions upstream of the low pressure portion 12.
It can also be seen from fig. 1 that intermediate line L2 is also provided with a bleeder screw 13, particularly for bleeding air from low pressure pump 12 and intermediate line L2 downstream thereof. The first fuel port of spill valve 17 is connected to intermediate line L2 at a location downstream of bleeder screw 13. FIG. 1 also shows a hand pump 11 that may be used to manually displace air in the low pressure portion of the system, particularly in the oil inlet line L1 and the filter 14.
Fig. 1 also shows a start assist module 30 of the fuel injection system of the present application, and fig. 2 shows an enlarged view of the start assist module 30.
The start assist module 30 basically includes a control valve 32 having an off position (right position in fig. 1 and 2) and an on position (left position in fig. 1 and 2), an accumulator 34 having a preset maximum pressure, and a protective check valve 36. In the exemplary embodiment shown in the figures, the control valve 32 may be a solenoid valve, such as a pilot solenoid flow valve; the preset maximum pressure of the accumulator 34 may be 2-6 bar, preferably 4 bar. However, it will be understood by those skilled in the art that the control valve 32 may be configured as any type of valve capable of performing the same function, the preset maximum pressure of the accumulator 34 may be changed according to actual needs, and the check valve 36 may be replaced with any other type of relief valve.
In this particular embodiment, the control valve 32 has a first fuel port 32a in fluid communication with the intermediate line L2 at a location downstream of the fuel outlet of the low pressure pump 12; and a second fuel port 32b in fluid communication with the accumulator 34 and with the oil inlet line L1 via the check valve 36 at a location upstream of the fuel inlet of the low pressure pump 32. In the case where the control valve 32 is not energized, the control valve 32 is held at the shutoff position where the first fuel port 32a and the second fuel port 32b are not fluidly communicated by the spring force provided by the spring provided in the control valve 32; with the control valve 32 energized, the electromagnetic force counteracts the spring force to switch the control valve 32 to an on position that fluidly communicates its first and second fuel ports 32a, 32 b.
The following describes the principles by which vehicle engine starting can be improved using the start assist module 30.
Initially, prior to engine start-up, the control valve 32 is de-energized. As described above, control valve 32 is in its default open position under the influence of its spring force, and fuel in accumulator 34 is not communicated to fuel in intermediate line L2 between low and high pressure pumps 12, 22.
The control valve 32 is energized and the resulting electromagnetic force counteracts the spring force of the control valve 32 to switch the control valve 32 to the on position. At this time, the engine is not yet started, and the low-pressure pump 12 is not operated. The pressure at the first fuel port 32a of the control valve 32 is lower than the pressure at the second fuel port 32b of the control valve 32, which is provided by the accumulator 34, and the fuel of the accumulator 34 flows via the second fuel port 32b, via the control valve 32 and the first fuel port 32a, to the intermediate line L2, which is located downstream of the low-pressure pump 12. The fuel flows in the direction of the metering unit 16, so that the air in the intermediate line L2 is discharged via the bleeder screw 13. While venting air, the flowing fuel builds up pressure in intermediate line L2 to assist in subsequent engine starts.
Then, the engine of the vehicle is started. As the low pressure pump 12 starts to operate, the pressure at the fuel outlet of the low pressure pump 12 increases, with a consequent increase in the pressure at the first fuel port 32a of the control valve 32. The direction of fuel flow in the control valve changes when the pressure at the first fuel port 32a increases to exceed the pressure at the second fuel port 32b, which is in fluid communication with the accumulator 34. Fuel from the fuel outlet of the low pressure pump 12 begins to flow to the accumulator 34 via the control valve 32, effecting filling of the accumulator 34. At the same time, this prevents the pressure at the then outlet of the low-pressure pump 12 from being too high, and thus prevents too much fuel from entering the high-pressure pump 22 via the metering unit 16.
During this time, as fuel is filled into the accumulator 34, the pressure of the accumulator 34 increases. When the pressure of the accumulator 34 increases to its predetermined maximum pressure, the relief valve 36 opens and fuel from the second fuel port 32b of the control valve 32 no longer fills the accumulator 34 but flows upstream of the low pressure pump 12 via the relief valve 36 and into the low pressure pump 12 until the control valve 32 is de-energized. This serves to protect the accumulator 34.
Typically, the control valve 34 has a preset on period, i.e., the control valve 32 is in the on position for the preset on period and then automatically de-energized, the control valve 32 returning to the off position.
In one embodiment of the present application, the pressure at the fuel outlet of the low pressure pump 12 may be about 1 bar before engine start and greater than 4 bar after engine start. The pressure in the accumulator 34 may be greater than 3 bar before the engine is started and the preset maximum pressure may be about 4 bar.
According to the above, before the engine is started, the control valve 32 is first energized and the fuel of the accumulator 34 first builds up pressure in the intermediate line L2 between the low-pressure pump 12 and the high-pressure pump 22, on the one hand enabling a rapid evacuation of air from the low-pressure part of the system and on the other hand improving the starting performance during the subsequent engine start, in particular after a replacement of system components or in the case of a long engine stop. In addition, the engine starting capability can be improved under the cold working condition and the high-altitude working condition. Providing a start assist module reduces the cost required compared to providing an electric fuel delivery pump.
In addition, a relief valve 36 is provided in the start assist module 30 to avoid excessive pressure at the fuel outlet of the low pressure pump 12 from affecting or reducing the life of associated components in the system, improving the life and reliability of the pump or the overall system.
The embodiments shown in the drawings and described above are provided for purposes of illustration and description and are not intended to limit the scope of the present application. On reading the present application, those skilled in the art may modify the details of construction, forms and so on, or substitute equivalents thereof, without departing from the scope of protection defined by the following claims, which are intended to be covered by the present disclosure.

Claims (10)

1. A fuel injection system for a vehicle includes a low-pressure pump (12), a high-pressure pump (22), an oil feed line (L1) in fluid communication with a fuel inlet of the low-pressure pump (12), and an intermediate line (L2) fluidly communicating a fuel outlet of the low-pressure pump (12) with a fuel inlet of the high-pressure pump (22),
characterized in that the fuel injection system further comprises a start assist module (30) comprising a control valve (32), an accumulator (34) and a safety valve (36), the control valve (32) comprising a first fuel port (32a) and a second fuel port (32b), and has an off position in which the first and second fuel ports (32a, 32b) are not fluidly connected when de-energized and an on position in which the first and second fuel ports (32a, 32b) are fluidly connected when energized, wherein the first fuel port (32a) is in fluid communication with the intermediate line (L2) at a location downstream of the low pressure pump (12), the second fuel port (32b) is in fluid communication with the accumulator (34) and with the oil inlet line (L1) at a location upstream of the low pressure pump (12) via the relief valve (36).
2. A fuel injection system according to claim 1, characterized in that the control valve (32) is a solenoid valve.
3. A fuel injection system according to claim 2, characterized in that the control valve (32) is a pilot operated electromagnetic flow valve.
4. A fuel injection system according to claim 1, characterized in that the safety valve (36) is a one-way valve or a check valve.
5. A fuel injection system according to claim 1, characterized in that the accumulator (34) has a preset maximum pressure.
6. The fuel injection system of claim 1, further comprising a hand pump (11) and a filter (14) disposed on the oil feed line (L1).
7. The fuel injection system according to claim 1, further comprising a bleeder screw (13) provided on the intermediate line (L2).
8. Fuel injection system according to claim 1, characterized in that it further comprises a metering unit (16) arranged on the intermediate line (L2) between the low-pressure pump (12) and the high-pressure pump (22).
9. Fuel injection system according to claim 8, characterized in that it further comprises a zero delivery valve (15), said zero delivery valve (15) being in fluid communication with said intermediate line (L2) at a position located between the metering unit (16) and the high-pressure pump (22) and being connected to said inlet line (L1) at a position upstream of said low-pressure pump (12).
10. A vehicle characterized by comprising a fuel injection system according to any one of claims 1-9.
CN201920910194.7U 2019-06-17 2019-06-17 Fuel injection system for vehicle and vehicle Active CN210118216U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201920910194.7U CN210118216U (en) 2019-06-17 2019-06-17 Fuel injection system for vehicle and vehicle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201920910194.7U CN210118216U (en) 2019-06-17 2019-06-17 Fuel injection system for vehicle and vehicle

Publications (1)

Publication Number Publication Date
CN210118216U true CN210118216U (en) 2020-02-28

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN201920910194.7U Active CN210118216U (en) 2019-06-17 2019-06-17 Fuel injection system for vehicle and vehicle

Country Status (1)

Country Link
CN (1) CN210118216U (en)

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