High-pressure common rail fuel system, high-pressure common rail control method and engine system

Abstract

The application belongs to the technical field of engines, and discloses a high-pressure common rail fuel system, a high-pressure common rail control method and an engine system. The high-pressure common rail fuel system comprises a high-pressure common rail pipe, and an oil tank, a coarse filter, an oil pump, a fine filter and an oil injection pump connected in sequence. The oil outlet of the oil injection pump is selectively connected with the high-pressure common rail pipe, and the oil return port of the oil injection pump is selectively connected with the oil inlet of the oil tank or the coarse filter. By using the high-pressure common rail control method, the phenomenon of negative pressure suction in the coarse filter can be effectively improved, and the problem of engine flameout caused by difficult rail pressure building can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine technology, and in particular to a high-pressure common rail fuel system, a high-pressure common rail control method and an engine system. BACKGROUND

[0002] The high-pressure common rail fuel system includes a low-pressure oil circuit and a high-pressure oil circuit. The low-pressure oil circuit is generally under negative pressure, and the high-pressure oil circuit is generally under positive pressure. Fuel in the low-pressure oil circuit is filtered by a coarse filter and a fine filter and is pumped into a high-pressure oil pump by an oil pump. The high-pressure oil pump then pumps high-pressure oil into a common rail pipe. The common rail pipe is connected to injectors of each cylinder of the engine through a high-pressure oil pipe, and the injectors spray oil into the cylinder of the engine.

[0003] Currently, in order to solve the problem of difficult rail pressure build-up and easy engine stall caused by gas in the low-pressure oil circuit during engine starting, an exhaust structure is usually arranged in the low-pressure oil circuit and / or an exhaust hole is arranged on the coarse filter. However, when the exhaust structure on the low-pressure oil circuit and the exhaust hole on the coarse filter cannot exhaust gas abnormally, gas will still accumulate in the coarse filter, causing the coarse filter to still have a negative pressure gas separation phenomenon, which ultimately still causes the engine to stall. When the engine is stopped, the gas on the outside of the filter element cannot be discharged due to the negative pressure on the inside of the filter element. As the gas continues to accumulate, the liquid level on the outside of the filter element continues to drop, the liquid level difference between the inside and outside of the filter element increases, and the air on the outside of the filter element enters the inside of the filter element after the engine stalls. When the engine is started again, the gas on the inside of the filter element will be discharged first to form a continuous gas column, which causes the oil pump to fail to pump oil normally, thereby causing the engine to still have a stall phenomenon. SUMMARY

[0004] The present application aims to provide a high-pressure common rail fuel system, a high-pressure common rail control method and an engine system to solve the above-mentioned problems existing in the prior art high-pressure common rail fuel system.

[0005] To achieve this purpose, the present application adopts the following technical solutions:

[0006] The high-pressure common rail fuel system comprises a high-pressure common rail pipe, and an oil tank, a coarse filter, an oil pump, a fine filter and an oil injection pump connected in sequence. The oil outlet of the oil injection pump is selectively connected to the high-pressure common rail pipe, and the oil return port of the oil injection pump is selectively connected to the oil inlet of the oil tank or the coarse filter.

[0007] As a preferred solution of the above-mentioned high-pressure common rail fuel system, the high-pressure common rail fuel system further comprises a control valve, which selectively connects the oil return port of the oil injection pump to the oil inlet of the oil tank or the coarse filter.

[0008] As a preferred solution of the high-pressure common rail fuel system, the control valve is a two-position three-way electromagnetic valve, an input port of the two-position three-way electromagnetic valve is communicated with the oil return port of the fuel injection pump, one output port of the two-position three-way electromagnetic valve is communicated with the oil tank, and the other output port of the two-position three-way electromagnetic valve is communicated with the oil inlet of the coarse filter.

[0009] As a preferred solution of the high-pressure common rail fuel system, the control valve includes two electromagnetic switch valves, input ports of the two electromagnetic switch valves are communicated with the oil return port of the fuel injection pump, an output port of one of the electromagnetic switch valves is communicated with the oil inlet of the coarse filter, and an output port of the other electromagnetic switch valve is communicated with the oil tank.

[0010] A high-pressure common rail control method is used in the high-pressure common rail fuel system, and the high-pressure common rail control method includes:

[0011] After the T15 is powered on, the working mode is determined according to the T15 power-on state and the engine speed;

[0012] The high-pressure common rail fuel system is controlled to operate in the determined working mode;

[0013] The working mode includes a first working mode and a second working mode;

[0014] The first working mode is that the oil return port of the fuel injection pump is communicated with the oil inlet of the coarse filter;

[0015] The second working mode is that the oil return port of the fuel injection pump is communicated with the oil tank.

[0016] As a preferred solution of the high-pressure common rail control method, the step of determining the working mode according to the T15 power-on state and the engine speed includes:

[0017] It is determined in real time whether the T15 power-on state is changed to a T15 power-off state;

[0018] If the T15 power-on state is changed to the T15 power-off state, the working mode is determined to be the first working mode.

[0019] As a preferred solution of the high-pressure common rail control method, when the T15 power-on state is changed to the T15 power-off state, the oil outlet of the fuel injection pump is controlled to be disconnected from the high-pressure common rail pipe.

[0020] As a preferred solution of the high-pressure common rail control method, the step of determining the working mode according to the T15 power-on state and the engine speed further includes:

[0021] Before the engine is started, the working mode is determined to be a default working mode; the default working mode is the first working mode or the second working mode.

[0022] After the engine starts, it is determined in real time whether the engine speed is in a set critical speed range;

[0023] If the engine speed is in the set critical speed range, the current working mode is kept unchanged;

[0024] If the engine speed is less than the minimum value of the set critical speed range, the working mode is determined as the first working mode;

[0025] If the engine speed is greater than the maximum value of the set critical speed range, the working mode is determined as the second working mode.

[0026] As a preferred solution of the high-pressure common rail control method, when the engine starts, the oil outlet of the fuel injection pump is controlled to be in communication with the high-pressure common rail pipe.

[0027] An engine system comprising the high-pressure common rail fuel system.

[0028] The present application has the following beneficial effects:

[0029] The present application provides a high-pressure common rail fuel system, comprising a high-pressure common rail pipe, and an oil tank, a coarse filter, a fuel delivery pump, a fine filter and a fuel injection pump connected in sequence, wherein the oil outlet of the fuel injection pump is selectively in communication with the high-pressure common rail pipe, and the oil return port of the fuel injection pump is selectively in communication with the oil inlet of the oil tank or the coarse filter. By using the high-pressure common rail fuel system, the phenomenon of negative pressure suction in the coarse filter can be effectively improved, and the problem of engine stall caused by difficulty in building rail pressure can be effectively improved.

[0030] The present application also provides a high-pressure common rail control method for implementing the high-pressure common rail fuel system. The high-pressure common rail control method comprises: determining a working mode according to the T15 power-on state and the engine speed after the T15 is powered on; controlling the high-pressure common rail fuel system to operate according to the determined working mode; the working mode comprises a first working mode and a second working mode; the first working mode is that the oil return port of the fuel injection pump is in communication with the oil inlet of the coarse filter; and the second working mode is that the oil return port of the fuel injection pump is in communication with the oil tank. By using the high-pressure common rail control method to control the high-pressure common rail fuel system, the phenomenon of negative pressure suction in the coarse filter can be effectively improved, and the problem of engine stall caused by difficulty in building rail pressure can be effectively improved.

[0031] The present application also provides an engine system comprising the high-pressure common rail fuel system. By using the high-pressure common rail fuel system, the working reliability of the engine system can be effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1The principle of the high-pressure common rail fuel system provided by the specific embodiment of the present application Figure 1 ;

[0033] Figure 2 The principle of the high-pressure common rail fuel system provided by the specific embodiment of the present application Figure 2 ;

[0034] Figure 3 The flow of the high-pressure common rail control method provided by the specific embodiment of the present application Figure 1 ;

[0035] Figure 4 The flow of the high-pressure common rail control method provided by the specific embodiment of the present application Figure 2 ;

[0036] Figure 5 The flow of the high-pressure common rail control method provided by the specific embodiment of the present application Figure 3 .

[0037] In the drawings:

[0038] 1, oil tank; 2, coarse filter; 3, oil pump; 4, fine filter; 5, fuel injection pump; 61, two-position three-way electromagnetic valve; 62, electromagnetic switch valve. DETAILED DESCRIPTION

[0039] The present application will be further described below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0040] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood in a broad sense, for example, it can be fixedly connected, or detachably connected, or integrated; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0041] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature is "on", "above" and "over" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature is "under", "below" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0042] In the description of the present embodiment, the terms "upper", "lower", "right", "left", and other orientation or position relationships are based on the orientation or position relationships shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used to distinguish in the description and do not have special meanings.

[0043] The present application provides a high-pressure common rail fuel system, such as Figure 1 and Figure 2 shown, comprising a high-pressure common rail pipe, and an oil tank 1, a coarse filter 2, an oil pump 3, a fine filter 4 and an injection pump 5 connected in sequence, the oil outlet of the injection pump 5 can be selectively connected with the high-pressure common rail pipe, and the oil return port of the injection pump 5 can be selectively connected with the oil inlet of the oil tank 1 or the coarse filter 2.

[0044] The present application also provides a high-pressure common rail control method for implementing the above-mentioned high-pressure common rail fuel system. As shown in Figures 3-5 , the high-pressure common rail control method comprises:

[0045] S100, after T15 is powered on, the working mode is determined according to the T15 power-on state and the engine speed.

[0046] Among them, the working mode includes a first working mode and a second working mode.

[0047] The first working mode is that the oil return port of the injection pump 5 is connected with the oil inlet of the coarse filter 2.

[0048] The second working mode is that the oil return port of the injection pump 5 is connected with the oil tank 1.

[0049] Specifically, as shown in Figure 3 and Figure 4 , the step S100 comprises:

[0050] S111, judging whether the T15 power-on state is changed to the T15 power-off state in real time.

[0051] If the T15 power-on state is changed to the T15 power-off state, it is determined that the working mode is the first working mode. Step S210 is executed, and step S112 is executed synchronously.

[0052] Specifically, the T15 power-on state being changed to the T15 power-off state refers to that the T15 power-on state is directly changed to the T15 power-off state, or the engine low-speed running state is directly changed to the T15 power-off state after the engine is started, or the engine high-speed running state is directly changed to the T15 power-off state after the engine is started. That is, any state after the T15 power-on state is directly changed to the T15 power-off state.

[0053] S112, the outlet of the fuel injection pump 5 is controlled to be disconnected from the high-pressure common rail pipe. Fuel injection into the engine cylinder is stopped.

[0054] Specifically, as shown in Figure 3 and Figure 5 , step S100 further includes:

[0055] S121, before the engine is started, it is determined that the working mode is the default working mode. The default working mode is the first working mode or the second working mode.

[0056] It can be understood that, after the T15 power-on state and before the engine is started, the fuel injection pump 5 does not need to inject fuel into the engine cylinder, the outlet of the fuel injection pump 5 is disconnected from the high-pressure common rail pipe, and the fuel in the high-pressure common rail fuel system does not flow. Therefore, at this time, the return port of the fuel injection pump 5 is connected to the inlet of the coarse filter 2, or the return port of the fuel injection pump 5 is connected to the fuel tank 1.

[0057] Alternatively, after the T15 power-on state and before the engine is started, it is determined that the working mode is the first working mode. Step S210 is executed. In this way, the working mode of the high-pressure common rail fuel system after the T15 power-on state and before the engine is started is the same as the working mode of the high-pressure common rail fuel system when the engine speed is less than the minimum value of the set critical speed range, and the number of switching working modes is reduced. As an alternative, after the T15 power-on state and before the engine is started, it is determined that the working mode is the second working mode. Step S220.

[0058] S122, when the engine is started, the outlet of the fuel injection pump 5 is controlled to be connected to the high-pressure common rail pipe. Fuel injection into the engine cylinder is enabled.

[0059] S123, after the engine is started, it is determined in real time whether the engine speed is in the set critical speed range.

[0060] If the engine speed is in the set critical speed range, the current working mode is kept unchanged.

[0061] If the engine speed is less than the minimum value of the set critical speed range, the working mode is determined as the first working mode. Step S210 is performed.

[0062] If the engine speed is greater than the maximum value of the set critical speed range, the working mode is determined as the second working mode. Step S220 is performed.

[0063] It can be understood that if the engine speed is always less than the minimum value of the set critical speed range, the working mode of the high-pressure common rail fuel system is always determined as the first working mode.

[0064] If the engine speed is always greater than the maximum value of the set critical speed range, the working mode of the high-pressure common rail fuel system is always determined as the second working mode.

[0065] If the engine speed decreases from a value greater than the maximum value of the critical speed range to a value within the set critical speed range, the working mode is maintained as the second working mode; when the engine speed further decreases to a value less than the minimum value of the set critical speed range, the working mode is determined as the first working mode.

[0066] If the engine speed increases from a value less than the minimum value of the critical speed range to a value within the set critical speed range, the working mode is maintained as the first working mode; when the engine speed further increases to a value greater than the maximum value of the set critical speed range, the working mode is determined as the second working mode.

[0067] In this way, the working mode of the high-pressure common rail fuel system is avoided from being frequently switched, so that the service life of each component in the high-pressure common rail fuel system can be effectively improved.

[0068] The set critical speed range is an experience range obtained from a large number of previous tests, or the set critical speed range is a set range set according to the working requirements of the engine system.

[0069] Specifically, in the embodiment, the set critical speed range is set as 1000 r / min-1100 r / min.

[0070] S200, controlling the high-pressure common rail fuel system to operate according to the determined working mode.

[0071] Specifically, when the determined working mode is the first working mode, step S210 is performed: controlling the high-pressure common rail fuel system to operate according to the first working mode. That is, the oil return port of the fuel injection pump 5 is controlled to communicate with the oil inlet of the coarse filter 2.

[0072] Specifically, when the determined working mode is the second working mode, step S220 is performed: the common rail fuel system is controlled to operate in the second working mode. That is, the oil return port of the fuel injection pump 5 is controlled to communicate with the fuel tank 1.

[0073] Specifically, when the T15 is powered on, and the engine is in the engine starting state or the engine low-speed running state, that is, the engine speed is less than the minimum value of the set critical speed range, the oil outlet of the fuel injection pump 5 communicates with the high-pressure common rail pipe, the rotation speeds of the fuel pump 3 and the fuel injection pump 5 are both small, the amount of fuel delivered by the fuel injection pump 5 to the fuel injector and injected into the engine cylinder through the high-pressure common rail pipe is small, and is much smaller than the amount of fuel supplied by the fuel tank 1 to the fuel injection pump 5. Therefore, most of the fuel flowing into the fuel injection pump 5 will flow back through the oil return port of the fuel injection pump 5, and the pressure of the fuel flowing out of the oil return port of the fuel injection pump 5 is positive pressure. Therefore, when the engine is in the engine starting state or the engine low-speed running state, the oil return port of the fuel injection pump 5 is controlled to communicate with the oil inlet of the coarse filter 2, so that the coarse filter 2, the fuel pump 3, the fine filter 4 and the fuel injection pump 5 are sequentially communicated and form a circulating loop, so that the fuel flowing out of the oil return port of the fuel injection pump 5 flows into the coarse filter 2 to supplement the fuel in the coarse filter 2, so that the coarse filter 2 becomes a positive pressure environment, avoiding the air in the coarse filter 2 from being precipitated and accumulated, and effectively avoiding the negative pressure air suction phenomenon in the coarse filter 2 when the coarse filter 2 is filled with fuel; after the fuel flowing out of the oil return port of the fuel injection pump 5 flows into the coarse filter 2, it sequentially flows through the fuel pump 3, the fine filter 4 and the fuel injection pump 5, thereby effectively improving the oil pressure of the oil circuit from the coarse filter 2 to the fuel injection pump 5, promoting the flow of fuel, promoting the oil suction of the fuel pump 3 and promoting the oil suction of the fuel injection pump 5, thereby effectively improving the engine stall problem caused by the difficulty in building rail pressure when the engine is in the engine starting state or the engine low-speed running state; secondly, since the fuel pressure flowing out of the oil return port of the fuel injection pump 5 is positive, even if there is air in the coarse filter 2, the part of the fuel flowing into the coarse filter 2 can also disperse the air in the coarse filter 2, so that the air is dispersed and flows in the high-pressure common rail fuel system, thereby effectively avoiding the engine stall problem caused by the air column in the coarse filter 2.

[0074] It can be understood that before the coarse filter 2 is filled with fuel, the fuel flowing out of the oil return port of the fuel injection pump 5 disperses the air in the coarse filter 2, thereby effectively avoiding the engine stall phenomenon caused by the air column in the coarse filter 2. After the coarse filter 2 is filled with fuel, the negative pressure air suction phenomenon in the coarse filter 2 can be directly avoided. When the engine is in the engine starting state or the engine low-speed running state, the oil pressure of the oil circuit from the coarse filter 2 to the fuel injection pump 5 can be effectively improved, thereby effectively improving the engine stall problem caused by the difficulty in building rail pressure when the engine is in the engine starting state or the engine low-speed running state.

[0075] Specifically, the engine operating state further includes an engine high-speed operating state. It can be understood that the engine low-speed operating state and the engine high-speed operating state can be repeatedly switched after the engine starts. The critical speed range is set as the demarcation speed range between the engine low-speed operating state and the engine high-speed operating state.

[0076] When the engine is switched from the low-speed operating state to the high-speed operating state, i.e., the engine speed is greater than the maximum value of the set critical speed range, it indicates that the oil pressure of the oil circuit in which the fuel filter 2 and the fuel injection pump 5 are located meets the oil pressure requirement of the engine system in normal operation, and it is not necessary to continue to deliver fuel from the oil return port of the fuel injection pump 5 to the fuel filter 2 to increase the oil pressure of the oil circuit in which the fuel filter 2 and the fuel injection pump 5 are located. Therefore, the oil return port of the fuel injection pump 5 is controlled to be communicated with the oil tank 1, so that the oil tank 1, the fuel filter 2, the fuel transfer pump 3, the fuel filter 4 and the fuel injection pump 5 are sequentially communicated and form a circulation loop.

[0077] When the T15 is powered on and the T15 power-on state is switched to the T15 power-off state, the fuel injection pump 5 is controlled to be disconnected from the high-pressure common rail pipe, and all the fuel flowing into the fuel injection pump 5 flows out through the oil return port of the fuel injection pump 5. Therefore, when the T15 power-on state is switched to the T15 power-off state, the oil return port of the fuel injection pump 5 is controlled to be communicated with the oil inlet port of the fuel filter 2, so that the fuel filter 2, the fuel transfer pump 3, the fuel filter 4 and the fuel injection pump 5 are sequentially communicated and form a circulation loop. The fuel flowing out of the oil return port of the fuel injection pump 5 is positive pressure fuel, which flows into the fuel filter 2 to supplement the fuel in the fuel filter 2, so that the fuel in the fuel filter 2 is relatively more or even fills the fuel filter 2, thereby effectively improving the phenomenon of negative pressure suction in the fuel filter 2 when the engine starts next time, and effectively improving the problem of difficult rail pressure build-up caused by poor low-pressure fuel supply when the engine starts next time, thereby further reducing the phenomenon of engine stall caused by negative pressure suction and / or difficult rail pressure build-up after the engine starts next time.

[0078] Therefore, by using the high-pressure common rail control method described above to control the high-pressure common rail fuel injection system described above, the phenomenon of negative pressure suction in the fuel filter 2 can be effectively improved, and the problem of engine stall caused by difficult rail pressure build-up can be effectively improved.

[0079] It can be understood that after the engine starts, the fuel filter 2 will supplement the fuel from the oil tank 1 under the negative pressure of the fuel transfer pump 3 because the fuel injection pump 5 will inject fuel into the engine cylinder.

[0080] In the diesel vehicle, T15 power-on refers to that a specific circuit or configuration has been powered on, and the specific circuit and configuration are related to the vehicle model, which will not be described here.

[0081] Wherein, the engine starting refers to the process that the engine is turned from the static state to the running state.

[0082] Wherein, the high pressure common rail fuel system further comprises a control valve, the control valve can selectively connect the oil return port of the fuel injection pump 5 with the oil inlet of the oil tank 1 or the coarse filter 2.

[0083] Specifically, as shown in Figure 1 the control valve is a two-position three-way electromagnetic valve 61, the input port of the two-position three-way electromagnetic valve 61 is communicated with the oil return port of the fuel injection pump 5, one of the output ports of the two-position three-way electromagnetic valve 61 is communicated with the oil tank 1, and the other output port of the two-position three-way electromagnetic valve 61 is communicated with the oil inlet of the coarse filter 2. So as to achieve that the oil return port of the fuel injection pump 5 can be selectively connected with the oil inlet of the oil tank 1 or the coarse filter 2.

[0084] Further, when the two-position three-way electromagnetic valve 61 is powered on, the two-position three-way electromagnetic valve 61 connects the oil return port of the fuel injection pump 5 with the oil inlet of the coarse filter 2, and disconnects the oil return port of the fuel injection pump 5 with the oil tank 1; when the two-position three-way electromagnetic valve 61 is powered off, the two-position three-way electromagnetic valve 61 disconnects the oil return port of the fuel injection pump 5 with the oil inlet of the coarse filter 2, and connects the oil return port of the fuel injection pump 5 with the oil tank 1. As an alternative, when the two-position three-way electromagnetic valve 61 is powered on, the two-position three-way electromagnetic valve 61 disconnects the oil return port of the fuel injection pump 5 with the oil inlet of the coarse filter 2, and connects the oil return port of the fuel injection pump 5 with the oil tank 1; when the two-position three-way electromagnetic valve 61 is powered off, the two-position three-way electromagnetic valve 61 connects the oil return port of the fuel injection pump 5 with the oil inlet of the coarse filter 2, and disconnects the oil return port of the fuel injection pump 5 with the oil tank 1.

[0085] From the perspective of further improving the phenomenon of negative pressure suction in the coarse filter 2, it is preferred that when the two-position three-way electromagnetic valve 61 is powered on, the two-position three-way electromagnetic valve 61 disconnects the oil return port of the fuel injection pump 5 with the oil inlet of the coarse filter 2, and connects the oil return port of the fuel injection pump 5 with the oil tank 1; when the two-position three-way electromagnetic valve 61 is powered off, the two-position three-way electromagnetic valve 61 connects the oil return port of the fuel injection pump 5 with the oil inlet of the coarse filter 2, and disconnects the oil return port of the fuel injection pump 5 with the oil tank 1. So that the next time the engine starts, the fuel flowing out of the oil return port of the fuel injection pump 5 directly flows into the coarse filter 2 to further supplement the oil in the coarse filter 2, thereby further improving the phenomenon of negative pressure suction in the coarse filter 2 when the engine starts next time, and further improving the problem of difficult rail pressure building caused by poor low-pressure fuel supply when the engine starts next time.

[0086] From the perspective of saving control valve energy consumption and extending the service life of the control valve, it is preferred that when the two-position three-way solenoid valve 61 is energized, the two-position three-way solenoid valve 61 connects the oil return port of the fuel pump 5 with the oil inlet of the coarse filter 2, and disconnects the oil return port of the fuel pump 5 from the fuel tank 1. When the two-position three-way solenoid valve 61 is de-energized, the two-position three-way solenoid valve 61 disconnects the oil return port of the fuel pump 5 from the oil inlet of the coarse filter 2, and connects the oil return port of the fuel pump 5 to the fuel tank 1. Since the engine typically spends a longer time in high-speed operation after starting a vehicle than in the combined time spent in the starting and low-speed states, this configuration saves control valve energy consumption and extends the service life of the control valve.

[0087] In this embodiment, for example, when the two-position three-way solenoid valve 61 is energized, the two-position three-way solenoid valve 61 connects the oil return port of the fuel pump 5 with the oil inlet of the coarse filter 2 and disconnects the oil return port of the fuel pump 5 from the fuel tank 1; and when the two-position three-way solenoid valve 61 is de-energized, the two-position three-way solenoid valve 61 disconnects the oil return port of the fuel pump 5 from the oil inlet of the coarse filter 2 and connects the oil return port of the fuel pump 5 to the fuel tank 1. Then, when the vehicle ECU is powered off, the two-position three-way solenoid valve 61 loses power, disconnects the oil return port of the fuel pump 5 from the oil inlet of the coarse filter 2, and connects the oil return port of the fuel pump 5 to the fuel tank 1.

[0088] Specifically, the two-position three-way solenoid valve 61 and the fuel injection pump 5 are both electrically connected to the vehicle ECU.

[0089] Specifically, in this embodiment, when the T15 power-on state changes to the T15 power-off state and the vehicle ECU is powered off, the two-position three-way solenoid valve 61 loses power, and the operating mode of the high-pressure common rail fuel system automatically changes to the second operating mode.

[0090] As an alternative, Figure 2 As shown, the control valve includes two solenoid switch valves 62; the input ports of both solenoid switch valves 62 are connected to the oil return port of the fuel injection pump 5. The output port of one solenoid switch valve 62 is connected to the oil inlet of the coarse filter 2, and the output port of the other solenoid switch valve 62 is connected to the fuel tank 1. This allows the oil return port of the fuel injection pump 5 to be selectively connected to the fuel tank 1 or the oil inlet of the coarse filter 2. Both solenoid switch valves 62 are electrically connected to the vehicle ECU.

[0091] Specifically, the two electromagnetic switch valves 62 are a first electromagnetic switch valve and a second electromagnetic switch valve. The output port of the first electromagnetic switch valve is connected to the oil inlet of the coarse filter 2. The output port of the second electromagnetic switch valve is connected to the oil tank 1.

[0092] Further, when the first electromagnetic switch valve is powered, the input end of the first electromagnetic switch valve and the output end of the first electromagnetic switch valve are communicated; when the first electromagnetic switch valve is powered off, the input end of the first electromagnetic switch valve and the output end of the first electromagnetic switch valve are disconnected. When the second electromagnetic switch valve is powered, the input end of the second electromagnetic switch valve and the output end of the second electromagnetic switch valve are disconnected; when the second electromagnetic switch valve is powered off, the input end of the second electromagnetic switch valve and the output end of the second electromagnetic switch valve are communicated. Alternatively, when the first electromagnetic switch valve is powered, the input end of the first electromagnetic switch valve and the output end of the first electromagnetic switch valve are disconnected; when the first electromagnetic switch valve is powered off, the input end of the first electromagnetic switch valve and the output end of the first electromagnetic switch valve are communicated. When the second electromagnetic switch valve is powered, the input end of the second electromagnetic switch valve and the output end of the second electromagnetic switch valve are communicated; when the second electromagnetic switch valve is powered off, the input end of the second electromagnetic switch valve and the output end of the second electromagnetic switch valve are disconnected.

[0093] From the perspective of further improving the negative pressure suction phenomenon in the coarse filter 2, preferably, when the first electromagnetic switch valve is powered, the input end of the first electromagnetic switch valve and the output end of the first electromagnetic switch valve are disconnected; when the first electromagnetic switch valve is powered off, the input end of the first electromagnetic switch valve and the output end of the first electromagnetic switch valve are communicated. When the second electromagnetic switch valve is powered, the input end of the second electromagnetic switch valve and the output end of the second electromagnetic switch valve are communicated; when the second electromagnetic switch valve is powered off, the input end of the second electromagnetic switch valve and the output end of the second electromagnetic switch valve are disconnected.

[0094] From the perspective of saving the energy consumption of the control valve and prolonging the service life of the control valve, preferably, when the first electromagnetic switch valve is powered, the input end of the first electromagnetic switch valve and the output end of the first electromagnetic switch valve are communicated; when the first electromagnetic switch valve is powered off, the input end of the first electromagnetic switch valve and the output end of the first electromagnetic switch valve are disconnected. When the second electromagnetic switch valve is powered, the input end of the second electromagnetic switch valve and the output end of the second electromagnetic switch valve are disconnected; when the second electromagnetic switch valve is powered off, the input end of the second electromagnetic switch valve and the output end of the second electromagnetic switch valve are communicated.

[0095] Preferably, the oil delivery pump 3 is integrated into the fuel injection pump 5. The integration degree of the high-pressure common rail fuel system can be improved.

[0096] Specifically, the oil delivery pump 3 is a mechanical pump. The specific structure of the oil delivery pump 3 belongs to the prior art and will not be described here. The specific structures of the coarse filter 2 and the fine filter 4 also belong to the prior art and will not be described here.

[0097] The application also provides an engine system comprising the high-pressure common rail fuel system described above. By adopting the high-pressure common rail fuel system described above, the working reliability of the engine system can be effectively improved.

[0098] Obviously, the above embodiments of the present application are merely exemplary but not intended to limit the embodiments of the present application. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the scope of the present application. It is not necessary or possible to enumerate all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A high-pressure common rail control method, which is used in a high-pressure common rail fuel system, the high-pressure common rail fuel system comprising a high-pressure common rail pipe, and a fuel tank (1), a coarse filter (2), a fuel transfer pump (3), a fine filter (4) and a fuel injection pump (5) connected in sequence, and the fuel outlet of the fuel injection pump (5) can be selectively connected with or disconnected from the high-pressure common rail pipe, characterized in that, The oil return port of the fuel injection pump (5) can be selectively connected to the fuel tank (1) or the oil inlet of the coarse filter (2); the high-pressure common rail control method includes: After T15 is powered on, the operating mode is determined based on the T15 power-on status and engine speed; Controlling the high-pressure common rail fuel system to operate according to a determined working mode; The working mode includes a first working mode and a second working mode; The first working mode is: the oil return port of the fuel injection pump (5) is connected to the oil inlet of the coarse filter (2); The second working mode is that the oil return port of the fuel injection pump (5) is connected to the fuel tank (1).

2. The high-pressure common rail control method according to claim 1, characterized by, The high-pressure common rail fuel system further comprises a control valve, which can selectively connect the oil return port of the fuel injection pump (5) to the oil inlet of the fuel tank (1) or the coarse filter (2).

3. The high-pressure common rail control method according to claim 2, characterized by, The control valve is a two-position three-way solenoid valve (61), the input port of the two-position three-way solenoid valve (61) is connected to the oil return port of the fuel injection pump (5), one output port of the two-position three-way solenoid valve (61) is connected to the fuel tank (1), and the other output port of the two-position three-way solenoid valve (61) is connected to the oil inlet of the coarse filter (2).

4. The high-pressure common rail control method according to claim 2, characterized by, The control valve comprises two electromagnetic switch valves (62); the input ports of the two electromagnetic switch valves (62) are both connected to the oil return port of the fuel injection pump (5), the output port of one of the electromagnetic switch valves (62) is connected to the oil inlet of the coarse filter (2), and the output port of the other electromagnetic switch valve (62) is connected to the fuel tank (1).

5. The high-pressure common rail control method according to claim 1, characterized by, The steps for determining the operating mode based on the T15 power-on status and engine speed include: Real-time judgment of whether the T15 power-on state changes to the T15 power-off state; If the T15 power-on state is changed to the T15 power-off state, the operating mode is determined to be the first operating mode.

6. The high-pressure common rail control method according to claim 5, characterized by, When the T15 power-on state is changed to the T15 power-off state, the oil outlet of the fuel injection pump (5) is controlled to be disconnected from the high-pressure common rail pipe.

7. The high-pressure common rail control method according to any one of claims 5-6, characterized in that, The step of determining the operating mode according to the T15 power-on state and the engine speed also includes: Before starting the engine, determining that the operating mode is a default operating mode; the default operating mode is the first operating mode or the second operating mode; After the engine is started, it is determined in real time whether the engine speed is within the set critical speed range; If the engine speed is within the set critical speed range, the current working mode remains unchanged; If the engine speed is less than the minimum value of the set critical speed range, determining the operating mode to be the first operating mode; If the engine speed is greater than the maximum value of the set critical speed range, the operating mode is determined to be the second operating mode.

8. The high-pressure common rail control method according to any one of claims 5-6, characterized in that, When the engine is started, the oil outlet of the fuel injection pump (5) is controlled to communicate with the high-pressure common rail pipe.

9. An engine system characterized by, Used to implement the high-pressure common rail control method according to any one of claims 1 to 8.

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