A diesel engine electronically controlled high pressure common rail fuel supply pump

Abstract

A diesel engine electronically controlled high-pressure common rail fuel pump, consisting of a camshaft, an aluminum pump body, a gear-type fuel pump, a plunger sleeve, a plunger, a tappet body, a plunger spring, a spring seat, an oil inlet valve, an oil outlet valve, an oil inlet connecting screw with a pressure stabilizing device, an electromagnetic valve, etc.; the camshaft is installed in the middle of the pump body, and the axial direction is the camshaft, the end cover, the pump body and the gear-type fuel pump in sequence; the tappet body contacts the cam of the camshaft, and the other side of the tappet body contacts the plunger; the camshaft rotates to drive the tappet body and the plunger to reciprocate up and down to complete the process of sucking and pumping oil; the oil inlet connecting screw with the pressure stabilizing device is a one-way valve added to the oil inlet screw. When the oil inlet pressure is too large, the stabilizing device opens and the oil inlet pressure is released to stabilize the pressure.

Description

Technical Field

[0001] The invention relates to the technical field of diesel engine high pressure common rail fuel pumps, and in particular to a low-cost electronically controlled high pressure common rail fuel supply pump for non-road diesel engines below 40 kW. Background Art

[0002] The use of high-pressure common rail fuel injection systems on diesel engines has become one of the main development trends in diesel engine technology in the world today. High-pressure common rail fuel injection systems can not only achieve stable high-pressure injection to improve the combustion process, but also independently control the injection characteristics, greatly improving the power, economy and emissions of diesel engines.

[0003] The high-pressure common rail fuel system specifically includes common rail pump, common rail pipe, injector, ECU, sensor and other components. The fuel is fed from the fuel tank to the common rail pump through the fuel filter, and then pressurized in the plunger cavity and sent to the common rail pipe. The pressure in the common rail pipe is controlled according to the pressure regulation signal sent by the ECU. The fuel is fed to the injector through the high-pressure oil pipe. The injector sprays the fuel into the combustion chamber of the diesel engine with appropriate injection action according to the command sent by the ECU. The common rail pump is an important component of this high-pressure common rail fuel injection system with excellent environmental performance, which can realize the rational control of the common rail pressure.

[0004] Most of the existing low-power diesel engines use mechanical pumps. The mechanical inline injection pump system has low injection pressure, slow oil volume control conversion under changing working conditions, and cannot accurately control the oil volume and injection time under all working conditions, resulting in the diesel engines that match it being unable to meet the increasingly stringent emission regulations. The common rail pump has a high sales price, high maintenance cost, and poor oil adaptability. There is a clear demand in the market for low-cost common rail pumps for non-road diesel engines around 40kw. Summary of the invention

[0005] The present invention provides an electronically controlled high-pressure common rail fuel supply pump for a diesel engine, comprising an aluminum pump body, a gear-type fuel pump, a camshaft, an oil pumping component, a tappet body, an oil inlet valve, a solenoid valve and an oil outlet valve, wherein the oil pumping component comprises a plunger sleeve, a plunger and a plunger spring, and only a fuel oil channel is provided in the aluminum pump body; the plunger sleeve is arranged on the upper part of the aluminum pump body; and the pump also comprises an oil inlet connecting screw with an oil inlet pressure stabilizing device, wherein the oil inlet connecting screw is arranged on the left and right sides of the plunger sleeve at the same height as the oil inlet valve and the solenoid valve, and a fuel channel is provided in the plunger sleeve; the oil inlet connecting screw is provided with an oil pressure stabilizing device, and the oil pressure stabilizing device is composed of a steel ball, a spring, an oil return joint and an oil inlet screw, wherein a spring mounting hole is provided in the oil return joint, and a steel ball sealing surface is provided in the oil inlet screw, and after the spring and the steel ball are installed in the oil return joint, they are screwed into the head side of the oil inlet screw together.

[0006] Furthermore, the solenoid valve is in an oil cut-off control mode, and the oil inlet valve is composed of an oil inlet valve seat, an oil inlet valve stem, and a magnet; a magnet is welded on the oil inlet valve stem, and the other side of the magnet is the solenoid valve. The oil inlet valve is in a normally open state. When the solenoid valve is energized, the magnet is attracted to move the oil inlet valve stem toward the solenoid valve side, closing the oil inlet channel.

[0007] Furthermore, the fuel enters the first fuel oil channel of the plunger sleeve from the oil inlet connecting screw, then passes through the oil channel in the oil inlet valve seat, enters the second fuel oil channel of the plunger sleeve when the oil inlet valve stem is normally open, and finally reaches the plunger cavity; the first fuel oil channel and the second fuel oil channel are evenly arranged coaxially with the oil inlet connecting screw, the oil inlet valve, and the solenoid valve, there are 2 first fuel oil channels and 4 second fuel oil channels.

[0008] Furthermore, the camshaft is supported by sliding bearings at both ends, and a forced lubrication oil channel is provided in the pump body to enter the bearings on both sides. The sliding bearing adopts a flanged bearing and is an integrated sliding bearing with axial thrust. The inner hole and thrust surface of the bearing are both designed with a friction-reducing coating.

[0009] Furthermore, a camshaft mounting hole is provided inside the connecting key between the gear-type oil pump and the camshaft, and the outside is in the shape of a six-pointed star. A keyway of the same shape is provided on the gear, into which the connecting key can be inserted. The connecting key material is polyetheretherketone.

[0010] The invention is developed to meet the demand for low-cost common rail pumps for non-road diesel engines with a power of about 40KW in the existing market. The fuel supply pump consists of a camshaft, an aluminum pump body, a gear-type fuel pump, a plunger sleeve, a plunger, a tappet body, a plunger spring, a spring seat, an inlet valve, an outlet valve, an inlet connection screw with a pressure stabilizing device, and a solenoid valve.

[0011] The camshaft is installed in the middle of the pump body, and the axial direction is the camshaft, end cover, pump body and gear oil pump. The tappet body contacts the camshaft cam, and the other side of the tappet body contacts the plunger. The camshaft rotates, driving the tappet body and plunger to reciprocate up and down to complete the process of sucking and pumping oil. The oil inlet connecting screw with a pressure stabilizing device is a one-way valve added to the oil inlet screw. When the oil inlet pressure is too high, the stabilizing device opens and the oil inlet pressure is released to stabilize the pressure.

[0012] The present invention has a higher injection pressure, faster oil quantity control conversion under changing working conditions, and can accurately control the oil quantity and injection time under all working conditions, which can meet the requirements of increasingly stringent emission regulations. In addition, the present invention has low maintenance costs and good oil adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the radial cross-sectional structure of the present invention.

[0014] Figure 2It is a schematic diagram of the axial section structure of the present invention.

[0015] Figure 3 It is a structural schematic diagram of the oil inlet connecting screw with the oil inlet pressure stabilizing device of the present invention.

[0016] Figure 4 It is a schematic diagram of the axial structure of the plunger fuel oil channel of the present invention.

[0017] Figure 5 It is a schematic diagram of the radial structure of the plunger fuel oil channel of the present invention. DETAILED DESCRIPTION

[0018] refer to Figure 1 , 2 , 3, 4 and 5,

[0019] A diesel engine electronically controlled high-pressure common rail fuel supply pump, wherein the camshaft 3 is installed in the middle of an aluminum pump body 1, and the axial direction is the pump body 1, the gear-type oil pump 2, the cam position, and the top of the pump body are installed from bottom to top in sequence. The tappet body 5, the plunger 42, and the plunger sleeve 41 are installed coaxially on the left and right sides of the plunger sleeve 41. The fuel enters the plunger cavity 13 through the plunger sleeve fuel channel 10, the oil channel 11 of the oil inlet valve body, and the oil channel 12 through the oil inlet connecting screws. Under the driving action of the camshaft 3, the plunger 42 presses the fuel in the plunger cavity 13 out of the oil outlet valve 9. The camshaft 3 is supported by sliding bearings at both ends. A forced lubrication oil channel is provided in the pump body 1 to enter the bearings on both sides. The sliding bearing is a flanged axial thrust integrated bearing, and the inner hole and thrust surface of the bearing are designed with a friction-reducing coating. The camshaft 3 is connected to the gear-type oil pump 2 through a connecting key. The connecting key is a plate-type hexagram structure with a camshaft mounting hole in the center and a hexagram shape on the outside. There is a keyway of the same shape on the gear. The outside of the connecting key is inserted into the main drive gear and the inside is connected to the camshaft. The torque is transmitted through the rotation of the camshaft to drive the gear to rotate.

Claims

1. An electronically controlled high-pressure common rail fuel supply pump for a diesel engine, comprising an aluminum pump body (1), a gear-type fuel pump (2), a camshaft (3), an oil pump component (4), a tappet body (5), an oil inlet valve (7), a solenoid valve (8) and an oil outlet valve (9), wherein the oil pump component (4) comprises a plunger sleeve (41), a plunger (42) and a plunger spring (43), and only a fuel oil channel is provided in the aluminum pump body (1); the plunger sleeve (41) is arranged on the upper part of the aluminum pump body (1); and the characteristics are as follows: It also includes an oil inlet connecting screw (6) with an oil inlet pressure stabilizing device. The oil inlet connecting screw (6) is arranged at the same height as the oil inlet valve (7) and the solenoid valve (8) on the left and right sides of the plunger sleeve (41). The plunger sleeve (41) has a fuel passage. The oil inlet connecting screw (6) is provided with an oil pressure stabilizing device. The oil pressure stabilizing device is composed of a steel ball (61), a spring (62), an oil return joint (63) and an oil inlet screw (64). The oil return joint (63) is provided with a spring mounting hole. The oil inlet screw (64) is provided with a steel ball sealing surface. After the spring and the steel ball are installed in the oil return joint (63), they are screwed into the head side of the oil inlet screw (64) together. The solenoid valve (8) is in an oil cut-off control mode. The oil inlet valve (7) is composed of an oil inlet valve seat (71), an oil inlet valve stem (72) and a magnet (73). A magnet (73) is welded on the oil valve stem (72), and the other side of the magnet (73) is a solenoid valve (8). The oil inlet valve (7) is in a normally open state. When the solenoid valve (8) is energized, the magnet (73) is attracted to move the oil inlet valve stem (72) toward the solenoid valve side, thereby closing the oil inlet passage. The fuel enters the first fuel oil passage (10) of the plunger sleeve through the oil inlet connecting screw (6), and then passes through the oil passage (11) in the oil inlet valve seat (71). When the oil inlet valve stem (72) is in a normally open state, the fuel enters the second fuel oil passage (12) of the plunger, and finally reaches the plunger cavity (13). The first fuel oil passage (10) and the second fuel oil passage (12) are evenly arranged coaxially with the oil inlet connecting screw (6), the oil inlet valve (7), and the solenoid valve (8). There are two first fuel oil passages (10) and four second fuel oil passages (12).

2. The diesel engine electronically controlled high pressure common rail fuel pump according to claim 1, characterized in that: The camshaft (3) is supported by sliding bearings at both ends. A forced lubrication oil passage is provided in the pump body (1) to enter the bearings on both sides. The sliding bearing is a flanged bearing and is an integrated sliding bearing with an axial thrust. The inner hole and thrust surface of the bearing are both designed with a friction-reducing coating.

3. The diesel engine electronically controlled high pressure common rail fuel pump according to claim 1, characterized in that: The connecting key between the gear-type oil pump (2) and the camshaft (3) has a camshaft mounting hole inside and a six-pointed star shape outside. A keyway of the same shape is provided on the gear and can be inserted into the connecting key. The connecting key is made of polyetheretherketone.

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