Common rail fuel system for heavy duty 12v diesel engines

Abstract

The utility model discloses a kind of common rail fuel systems of heavy 12V diesel engine, belong to engine technical field, including the cylinder block of V-type arrangement, six cylinder holes are arranged on each side cylinder block;The high-pressure common rail pump is arranged in the inner wall middle part of the cylinder block of V-type arrangement, high-pressure oil pump is arranged in the lower part of the inner wall of the cylinder block of V-type arrangement, and the high-pressure oil pump is connected with common rail pipe by high-pressure oil pipe respectively;Fuel injector is arranged on the cylinder hole, and each side common rail pipe is connected with corresponding side several fuel injectors by several high-pressure oil pipes respectively.The utility model installs high-pressure common rail pump in fuel system according to diesel engine demand state, provides sufficient fuel supply for diesel engine, solves the arrangement problem in the V-type included angle of heavy 12V diesel engine common rail fuel system, and guarantees the sufficient fuel supply of heavy 12V diesel engine.

Description

Technical Field

[0001] This utility model relates to the field of engine technology, and in particular to a common rail fuel system for a heavy-duty 12V diesel engine. Background Technology

[0002] A common rail system typically includes a high-pressure fuel pump, a common rail, and high-pressure injectors. It's a fuel supply method that separates the fuel injection and pressure build-up processes. The high-pressure fuel pump builds up high pressure and delivers it to the common rail, which then connects to the injectors via high-pressure fuel lines. Most existing high-pressure common rail pumps have relatively small fuel capacity, and their size and mounting joints are too large. When matched with V-type diesel engines, they are often externally mounted on the outside of the crankcase, which cannot meet the requirements of heavy-duty 12V applications.

[0003] Matching a heavy-duty 12V diesel engine requires a rail pressure of 180 MPa, a transmission ratio of 1:1, a power of 900 kW, and the installation position must be within the V-angle, with an installation stop of only φ110 mm. Most existing high-pressure common rail pumps have a small oil volume, a large shape, and a large installation stop, and when matched with a V-type diesel engine, they are mostly mounted externally on the outside of the diesel engine crankcase. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a common rail fuel system for a heavy-duty 12V diesel engine. The high-pressure common rail pump in the fuel system is installed according to the requirements of the diesel engine to provide sufficient fuel supply to the diesel engine. This solves the problem of the arrangement of the common rail fuel system within the V-shaped angle of the heavy-duty 12V diesel engine and ensures sufficient fuel supply to the heavy-duty 12V diesel engine.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0006] A common rail fuel system for a heavy-duty 12V diesel engine includes a V-shaped cylinder block with six cylinder bores on each side; a common rail is installed in the middle of the inner wall of the V-shaped cylinder block, and a high-pressure fuel pump is installed in the lower part of the inner wall of the V-shaped cylinder block, with the high-pressure fuel pump connected to the common rail via high-pressure fuel lines; fuel injectors are installed on the cylinder bores, and the common rail on each side is connected to several fuel injectors on the corresponding side via several high-pressure fuel lines.

[0007] A further improvement of this utility model's technical solution is as follows: the high-pressure oil pump includes a low-pressure chamber, a high-pressure chamber, and a lubrication chamber connected in sequence; the low-pressure chamber includes an oil pump, a filter, and an oil inlet metering valve connected in sequence; an overflow valve is provided between the filter and the oil inlet metering valve; the oil pump is connected to the oil tank, and a pressure limiting valve and a venting valve are provided on the bypass of the oil pump; the high-pressure chamber includes an oil inlet valve and an oil outlet valve; the lubrication chamber includes a plunger sleeve, a plunger body disposed within the plunger sleeve, a tappet disposed at the bottom of the plunger body, and a camshaft disposed at the bottom of the tappet; the upper end of the plunger sleeve is connected to the high-pressure chamber, and a pressure relief hole is provided on the side of the plunger sleeve; the oil inlet metering valve and the oil discharge hole are both connected to a zero-flow valve, and then connected to the oil tank through an external return oil circuit.

[0008] A further improvement of this utility model is that the plunger of the high-pressure oil pump has a diameter of φ9mm, a lift of 15mm, and a circulating oil injection volume of more than 3800ml, and is a two-cylinder, two-action pump.

[0009] A further improvement of this utility model's technical solution is that: the injector includes a body, an electromagnet disposed on the top of the body, an armature disposed inside the body, a valve assembly connected to the armature, and a needle valve disposed at the bottom of the body; the body is inverted conical in shape, with a central high-pressure chamber inside, a high-pressure oil inlet hole connected to the central high-pressure chamber in the middle of the body, and a spray hole disposed at the bottom of the body; the bottom of the needle valve blocks the oil outlet hole, a coupling sleeve is fitted on the upper part, and the side is connected to the valve assembly through a valve stem; an oil outlet throttling hole is disposed below the armature.

[0010] A further improvement of the present invention is that the fuel injector is provided with eight holes, each with a diameter of 1.76 mm, a flow rate of 1.8 L / min, a cone angle of 148°, and axial distribution.

[0011] A further improvement of this utility model is that: the common rail includes an A-side common rail and a B-side common rail; eight oil ports are provided on the common rail, one of which is connected to the high-pressure oil pump, six of which are connected to the injector, and one is used as a balance port connected to the balance port on another common rail; the A-side common rail is connected to the rail pressure sensor; the B-side common rail is connected to the pressure relief valve through a pressure relief port that matches the pressure relief valve.

[0012] A further improvement of this utility model is that the inner length of the common rail tube is 303mm and the inner diameter is φ10mm.

[0013] The technological advancements achieved by this utility model due to the adoption of the above technical solution are as follows:

[0014] This invention solves the problem of large size and insufficient space for existing high-flow pumps within the V-angle of the common rail high-pressure pump for heavy-duty 12V diesel engines by using a high-pressure oil pump and injectors to gradually increase pressure. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the common rail fuel system of the medium and heavy-duty 12V diesel engine of this utility model;

[0016] Figure 2 This is a schematic diagram of the medium-high pressure oil pump of this utility model;

[0017] Figure 3 This is an external view of the medium-high pressure oil pump of this utility model;

[0018] Figure 4 This is a cross-sectional view of the fuel injector in this utility model;

[0019] Figure 5 This is a schematic diagram of the injector in this utility model.

[0020] Figure 6 This is a schematic diagram of the common rail pipe on side A in this utility model;

[0021] Figure 7 This is a schematic diagram of the common rail pipe on side B in this utility model;

[0022] Figure 8 This is a schematic diagram of the common rail fuel system operation principle of the medium and heavy-duty 12V diesel engine of this utility model;

[0023] Among them, 1. High-pressure oil pump, 101. Oil pump, 102. Filter, 103. Oil inlet metering valve, 104. Overflow valve, 105. Pressure limiting valve, 106. Vent valve, 107. Oil inlet valve, 108. Oil outlet valve, 109. Plunger sleeve, 110. Plunger body, 111. Tappet, 112. Camshaft, 113. Pressure relief hole, 114. Zero flow valve;

[0024] 2. Injector, 201. Body, 202. Electromagnet, 203. Armature, 204. Needle valve, 205. High-pressure chamber in the middle hole, 206. High-pressure oil inlet, 207. Coupling sleeve, 208. Valve stem, 209. Oil outlet throttle hole, 210. Valve assembly;

[0025] 3. Common rail pipe, 301. Rail pressure sensor, 302. Pressure relief valve;

[0026] 4. High-pressure oil pipe; 5. Diesel coarse filter; 6. Diesel fine filter. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0028] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0029] In the description of this utility model, "a number of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0030] like Figure 1 As shown, the common rail fuel system of the heavy-duty 12V diesel engine includes a V-shaped cylinder block with six cylinder bores on each side; a common rail pipe 3 is installed in the middle of the inner wall of the V-shaped cylinder block, and a high-pressure fuel pump 1 is installed in the lower part of the inner wall of the V-shaped cylinder block. The high-pressure fuel pump 1 is connected to the common rail pipe 3 through high-pressure fuel pipes 4; fuel injectors are installed on the cylinder bores, and the common rail pipe 3 on each side is connected to several fuel injectors on the corresponding side through several high-pressure fuel pipes 4.

[0031] like Figure 2 As shown, the high-pressure oil pump 1 includes a low-pressure chamber, a high-pressure chamber, and a lubrication chamber connected in sequence; the low-pressure chamber includes an oil pump 101, a filter 102, and an oil inlet metering valve 103 connected in sequence; an overflow valve 104 is provided between the filter 102 and the oil inlet metering valve 103; the oil pump 101 is connected to the oil tank, and a pressure limiting valve 105 and a vent valve 106 are provided on the bypass of the oil pump 101; the high-pressure chamber includes an oil inlet valve 107 and an oil outlet valve 108; the lubrication chamber includes a plunger sleeve 109, a plunger body 110 disposed within the plunger sleeve 109, a tappet 111 disposed at the bottom of the plunger body 110, and a camshaft 112 disposed at the bottom of the tappet 111; the upper end of the plunger sleeve 109 is connected to the high-pressure chamber, and a pressure relief hole 113 is provided on the side of the plunger sleeve 109; the oil inlet metering valve 103 and the oil discharge hole 113 are both connected to a zero-flow valve 114, and then connected to the oil tank through an external return oil circuit.

[0032] like Figure 3 As shown, in order to meet the fuel supply requirements of the heavy-duty 12V diesel engine, the length, width and height of the high-pressure oil pump 1 are 347mm, 123mm and 438mm respectively in the existing space. The plunger body 110 of the high-pressure oil pump 1 has a diameter of φ9mm, a lift of 15mm and a circulating fuel injection volume of 3817ml. It is a two-cylinder two-action pump.

[0033] like Figure 4As shown, the injector 2 includes a body 201, an electromagnet 202 disposed on the top of the body 201, an armature 203 disposed inside the body 201, a valve assembly 210 connected to the armature 203, and a needle valve 204 disposed at the bottom of the body 201. The body 201 is inverted conical in shape, with a central high-pressure chamber 205 inside. A high-pressure oil inlet 206 communicating with the central high-pressure chamber 205 is opened in the middle of the body 201, and a spray hole is disposed at the bottom of the body 201. The bottom of the needle valve 204 blocks the oil outlet, and a coupling sleeve 207 is clamped on the upper part. The side is connected to the valve assembly 210 through a valve stem 208. An oil outlet throttling hole 209 is disposed below the armature 203.

[0034] like Figure 5 As shown, the injector 2 has a length of 196mm and a maximum outer diameter of φ29mm.

[0035] like Figure 6 , Figure 7 As shown, the common rail pipe 3 includes an A-side common rail pipe and a B-side common rail pipe; the common rail pipe 3 is provided with eight oil ports, one of which is connected to the high-pressure oil pump 1, six of which are connected to the injector, and one is used as a balance port to communicate with the balance port on the other common rail pipe 3 to balance the pressure on both sides; the A-side common rail pipe is connected to the rail pressure sensor 301 to detect the rail pressure; the B-side common rail pipe is connected to the pressure relief valve 302 through a pressure relief port that matches the pressure relief valve 302, and is used for overpressure protection.

[0036] The common rail 3 has an inner length of 303mm and an inner diameter of φ10mm. The rail material is F38MnVS, and the rail hardness is 265~300HBW5 / 750, which can meet the rated working pressure of 180MPa for diesel engines.

[0037] Working principle:

[0038] like Figure 8 As shown, the oil pump 101 integrated on the high-pressure oil pump 1 draws oil from the oil tank and enters the high-pressure pump chamber through the diesel coarse filter 5 and the diesel fine filter 6. The high-pressure oil pump 1 establishes high pressure and supplies oil to the high-pressure injector 2 through the high-pressure oil pipe 4 and the common rail pipe 3, and the injector 2 performs direct injection in the cylinder.

[0039] In the high-pressure oil pump 1, the camshaft 112 drives the plunger to reciprocate. The oil pump 101 delivers fuel from the tank to the inlet of the inlet valve 107. When the plunger moves downward, the pressure of the oil pump 101 pushes open the inlet valve 107, allowing fuel to enter the plunger chamber. When the plunger body 110 moves upward, the pressure of the plunger chamber closes the inlet valve 107 and opens the outlet valve 108, allowing high-pressure oil to enter the common rail 3. Changing the duty cycle of the PWM control signal of the metering valve 103 can change the flow area of ​​the metering valve 103, thereby changing the high-pressure flow rate to meet the injection quantity and rail pressure requirements of the common rail system. The overflow valve is used to return excess flow from the oil pump 101 to the tank, and the zero-flow valve 114 is used to return leakage flow from the solenoid valve to the tank when the high-pressure pump stops.

[0040] In injector 2, high-pressure fuel enters the injector 2 assembly from the high-pressure inlet and directly enters the high-pressure chamber 205 in the middle hole. When the electromagnet 202 is not energized, the needle valve 204 experiences a downward force, closing the injection orifice. When the electromagnet 202 is energized, the valve stem 208 moves upward against the spring force of the coupling sleeve 207, opening the needle valve 204. Unlike traditional mechanical injectors, this injector uses an electronically controlled injector. Injector 2 has a solenoid valve circuit interface at one end. When the ECU issues an injection command, high-pressure fuel is injected into the diesel engine cylinder through injector 2, while a small amount of return fuel enters the return pipe and returns to the diesel tank. Injector 2 uses a coupling sleeve 207 structure. The solenoid valve includes an electromagnet 202 and an armature 203, with the solenoid valve positioned at the top. A servo system controls the injector nozzle. The injector nozzle has eight holes with a diameter of 0.176 mm, a flow rate of 1.8 L / min, a cone angle of 148°, axial distribution, and no static leakage.

[0041] In summary, this utility model installs the high-pressure common rail pump in the fuel system according to the diesel engine's requirements, providing sufficient fuel supply to the diesel engine, solving the arrangement problem within the V-angle of the common rail fuel system for heavy-duty 12V diesel engines, and ensuring sufficient fuel supply for heavy-duty 12V diesel engines.

Claims

1. A common rail fuel system for a heavy-duty 12V diesel engine, comprising a V-shaped cylinder block with six cylinder bores arranged on each side of the cylinder block; characterized in that: The cylinder body wall of the V-shaped arrangement is provided with a common rail pipe (3) in the middle part, and a high-pressure oil pump (1) is provided at the lower part of the cylinder body wall of the V-shaped arrangement. The high-pressure oil pump (1) is connected to the common rail pipe (3) through a high-pressure oil pipe (4). The cylinder bore is provided with an injector, and the common rail pipe (3) on each side is connected to a number of injectors on the corresponding side through a number of high-pressure oil pipes (4).

2. The common rail fuel system for a heavy-duty 12V diesel engine according to claim 1, characterized in that: The high-pressure oil pump (1) includes a low-pressure chamber, a high-pressure chamber, and a lubrication chamber connected in sequence; the low-pressure chamber includes an oil pump (101), a filter (102), and an inlet metering valve (103) connected in sequence; an overflow valve (104) is provided between the filter (102) and the inlet metering valve (103); the oil pump (101) is connected to the oil tank, and a pressure limiting valve (105) and a vent valve (106) are provided on the bypass of the oil pump (101); the high-pressure chamber includes an inlet valve (107) and an outlet valve (108). 8); The lubrication chamber includes a plunger sleeve (109), a plunger body (110) disposed inside the plunger sleeve (109), a tappet (111) disposed at the bottom of the plunger body (110), and a camshaft (112) disposed at the bottom of the tappet (111); the upper end of the plunger sleeve (109) is connected to the high pressure chamber, and a pressure relief hole (113) is provided on the side of the plunger sleeve (109); the oil inlet metering valve (103) and the pressure relief hole (113) are both connected to the zero flow valve (114), and then connected to the oil tank through the external return oil circuit.

3. The common rail fuel system for a heavy-duty 12V diesel engine according to claim 2, characterized in that: The high-pressure oil pump (1) has a plunger body (110) with a diameter of φ9mm, a lift of 15mm, and a circulating oil injection volume of more than 3800ml. It is a two-cylinder, two-action pump.

4. The common rail fuel system for a heavy-duty 12V diesel engine according to claim 1, characterized in that: The injector (2) includes a body (201), an electromagnet (202) disposed on the top of the body (201), an armature (203) disposed inside the body (201), a valve assembly (210) connected to the armature (203), and a needle valve (204) disposed at the bottom of the body (201). The body (201) is inverted conical in shape, with a central high-pressure chamber (205) disposed inside. A high-pressure oil inlet (206) is opened in the middle of the body (201) to connect with the central high-pressure chamber (205). A spray hole is disposed at the bottom of the body (201). The needle valve (204) blocks the oil outlet hole at the bottom, and a coupling sleeve (207) is clamped at the top. It is connected to the valve assembly (210) on the side through a valve stem (208). An oil outlet throttling hole (209) is disposed below the armature (203).

5. The common rail fuel system for a heavy-duty 12V diesel engine according to claim 4, characterized in that: The fuel injector has eight holes with a diameter of 1.76 mm, a flow rate of 1.8 L / min, a cone angle of 148°, and is axially distributed.

6. The common rail fuel system for a heavy-duty 12V diesel engine according to claim 1, characterized in that: The common rail (3) includes an A-side common rail and a B-side common rail; the common rail (3) is provided with eight oil ports, one of which is connected to the high-pressure oil pump (1), six of which are connected to the injector, and one is used as a balance port to communicate with the balance port on another common rail (3); the A-side common rail is connected to the rail pressure sensor (301); the B-side common rail is connected to the pressure relief valve (302) through a pressure relief port that matches the pressure relief valve (302).

7. The common rail fuel system for a heavy-duty 12V diesel engine according to claim 6, characterized in that: The common rail tube (3) has an inner length of 303 mm and an inner diameter of φ10 mm.

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