High-power electronic unit pump capable of reducing plunger leakage rate

Abstract

The invention discloses a high-power electronic unit pump capable of reducing plunger leakage rate. The high-power electronic unit pump comprises a guide sleeve matched with an engine, a unit pump body mounted in the guide sleeve, a plunger spring, a roller body, a plunger assembled on the unit pump body, a sealing ring, an electromagnet, an armature, an electromagnetic valve spring, a control valve core, a check block and an adjusting base plate, the single pump body is characterized in that two ring grooves are machined in an inner hole, matched with the plunger, of the single pump body, the first ring groove is communicated with an oil return pipeline through an oil duct, the second ring groove is independently led out through an oil way to be connected with an oil return tank, a sealing ring groove is formed in the lower end of the second ring groove, and a movable sealing ring is assembled in the sealing ring groove. Lubricating oil is prevented from entering a fuel oil cavity through a plunger gap, and engine oil consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of electronically controlled unit pump technology, and in particular to a high-power electronically controlled unit pump that reduces plunger leakage. Background Technology

[0002] With increasingly stringent environmental protection requirements both domestically and internationally, the demands on diesel engine exhaust emissions and control are also rising, as are the performance requirements for the entire diesel engine. Compared to traditional mechanical fuel injection pumps, electronically controlled unit pumps offer better assurance of overall engine performance. However, high-power electronically controlled unit pumps typically require larger plunger diameters and camshaft lifts, resulting in excessive leakage through the plunger gap. On one hand, excessive plunger leakage leads to increased fuel consumption and decreased injection pressure, affecting engine performance and emissions standards. On the other hand, it can cause diesel fuel to leak into the lubrication lines, diluting the lubricating oil and affecting lubrication. In severe cases, it can even cause wear on critical components such as the camshaft and its rotating rollers. Additionally, a small amount of engine oil may enter the fuel chamber through the plunger gap, reducing the lifespan of the electronically controlled unit pump and impacting engine performance and reliability.

[0003] Chinese invention patent application publication number CN106593729A discloses an anti-internal leakage structure for a unit pump, comprising a first-stage groove, a second-stage groove, and a third-stage groove arranged sequentially from top to bottom along the axial direction of the plunger sleeve. The first-stage groove communicates with the fuel chamber through an oblique hole in the plunger sleeve. The third-stage groove communicates with the pressurized oil through an oil inlet channel in the plunger sleeve and an oil inlet hole in the pump body. The second-stage groove communicates with the mixing tank through an oil outlet channel in the plunger sleeve and an oil outlet hole in the pump body. This invention effectively prevents fuel leakage from the gap between the plunger and the plunger sleeve, avoids oil dilution, and effectively improves the service life of the unit pump.

[0004] Chinese Utility Model Patent Publication No. CN207609495U discloses a marine heavy-duty unit pump with an anti-external leakage structure, including a pump body and a plunger sleeve, plunger, oil quantity control rod, plunger spring, plunger spring lower seat, support body component, and oil outlet valve component installed in the pump body. The oil outlet connector on the oil outlet valve body is connected to a high-pressure oil pipe through a pipe connection nut. The oil outlet valve body has a first leakage oil return hole, a leakage oil return channel is provided between the oil outlet valve body and the plunger sleeve, a second leakage oil return hole is provided in the plunger sleeve, a leakage oil return annular cavity is provided between the plunger sleeve and the pump body, and a third leakage oil return hole and a zero-backpressure leakage oil return cavity are provided in the pump body. The oil leakage between the oil outlet connector on the oil outlet valve body, the pipe connection nut, and the high-pressure oil pipe flows back to the zero-backpressure leakage oil return cavity through the first leakage oil return hole, the leakage oil return channel, the second leakage oil return hole, the leakage oil return annular cavity, and the third leakage oil return hole.

[0005] However, the two patents mentioned above still suffer from unreasonable design, complex structure, and inability to effectively reduce plunger leakage. Summary of the Invention

[0006] The purpose of this invention is to address the problems of unreasonable design, complex structure, and inability to effectively reduce plunger leakage in existing technologies by providing a high-power electronically controlled unit pump with reasonable design, simple structure, effective reduction of leakage caused by plunger gap in electronically controlled unit pumps, prevention of fuel entering the lubricating oil line, and reduction of engine oil consumption.

[0007] To achieve the objectives of this invention, the technical solution adopted is as follows:

[0008] A high-power electronically controlled unit pump for reducing plunger leakage includes a guide sleeve that mates with the engine, a unit pump body, a plunger spring, and a roller body installed within the guide sleeve, and a plunger, a sealing ring, an electromagnet, an armature, a solenoid valve spring, a control valve core, a stop block, and an adjusting shim mounted on the unit pump body. The pump body is characterized by having two grooves machined in the inner hole where it mates with the plunger. The first groove connects to the return oil line via an oil passage, while the second groove is separately led out and connected back to the oil tank via an oil passage. A sealing ring groove is provided at the lower end of the second groove, and a suitable dynamic sealing ring is fitted within the sealing ring groove.

[0009] By employing the above technical solution, the present invention avoids lubricating oil from entering the fuel chamber through the plunger gap, thereby reducing oil consumption. Attached Figure Description

[0010] Figure 1 This is one of the internal cross-sectional views of the high-power electronically controlled unit pump for reducing plunger leakage according to the present invention.

[0011] Figure 2This is the second internal cross-sectional view of the high-power electronically controlled unit pump that reduces plunger leakage according to the present invention.

[0012] Figure 3 for Figure 2 Enlarged schematic diagram at point I.

[0013] Figure 4 This is the third internal cross-sectional view of the high-power electronically controlled unit pump used in this invention to reduce plunger leakage. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the invention is not limited to the scope of the embodiments described herein.

[0015] See Figures 1 to 4 The figure discloses a high-power electronically controlled unit pump that reduces plunger leakage. It includes a guide sleeve 11 that is fitted to the engine, a unit pump body 3, a plunger spring 12, and a roller body 13 installed in the guide sleeve 11, a plunger 4 and an electromagnet assembly 1 mounted on the unit pump body 3. Two grooves are machined in the inner hole of the unit pump body 3 and the plunger 4. The first groove 9 is connected to the return oil line through the oil passage 8, and the second groove 10 is led out separately through the oil passage 2 and connected to the oil tank or the zero back pressure return oil line. A sealing groove 6 is set at the lower end of the second groove 10, and a dynamic sealing ring 7 is installed in the sealing groove 6.

[0016] During engine operation, the rotation of the engine camshaft drives the roller assembly 5 to move up and down and compresses the fuel in the high-pressure chamber of the unit pump body 3 through the upward movement of the plunger 4. The high-pressure fuel is pressurized by the electromagnet assembly 1 (composed of a solenoid valve and control valve core, etc.) through the ECU and injected into the engine combustion chamber for combustion and power generation through the high-pressure fuel line and injector. Since the pressure in the high-pressure chamber can reach 100-160 MPa during the operation of the electronically controlled unit pump, high-pressure fuel leaks through the gap of the plunger 4. Most of the leaked oil returns to the return oil line through the first ring groove 9 and oil passage 8, while some leaked oil returns to the zero-backpressure return oil line through the second ring groove 10 and oil passage 2. Because a sealing ring groove 6 and a dynamic sealing ring 7 are added at the lower end, the remaining leaked oil cannot leak into the lubricating oil chamber through the gap of the plunger 4. This structure also prevents lubricating oil from entering the fuel chamber through the plunger gap, reducing oil consumption.

Claims

1. A high-power electronically controlled unit pump for reducing plunger leakage, comprising a guide sleeve for mounting with an engine, a unit pump body, a plunger spring, a roller body installed within the guide sleeve, and a plunger, a sealing ring, an electromagnet, an armature, a solenoid valve spring, a control valve core, a stop block, and an adjusting shim mounted on the unit pump body; characterized in that, Two ring grooves are machined in the inner hole of the unit pump body and the plunger. The first ring groove is connected to the oil return line through the oil passage, and the second ring groove is led out separately through the oil passage and connected back to the oil tank. A sealing ring groove is set at the lower end of the second ring groove, and a dynamic sealing ring is installed in the sealing ring groove.

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