Common-rail fuel oil jet system controlled by double electromagnetic valves and applied to low-speed diesel engine for ship

Abstract

The invention provides a common-rail fuel oil jet system controlled by double electromagnetic valves and applied to a low-speed diesel engine for a ship. The common-rail fuel oil jet system comprises a fuel oil supply portion and a common-rail jet device. The fuel oil supply portion supplies fuel oil and servo oil to the common-rail jet device. In the common-rail jet device, an upper pressurizing piston cavity and a lower pressurizing piston cavity are formed between a pressurizing piston and a pressurizing piston body, and the pressurizing piston control valve controls the fuel oil supply portion to be communicated or not communicated with the upper pressurizing piston cavity, so that fuel oil pressurization or fuel oil suction is achieved; the electromagnetic fuel oil jet control valve conducts fuel oil-working-condition accurate flexible control over fuel oil jet timing and the circulation jet amount, a pressurized high-pressure fuel oil path in the lower pressurizing piston cavity is divided into two paths, one path reaches a control cavity, and the other path reaches a fuel oil containing groove. According to the common-rail fuel oil jet system, the two electromagnetic valves are used for control, fuel oil is used as fuel and servo oil at the same time, the structure is simplified, cost is reduced, mutual independence between fuel oil pressurization and jet and repeated jet are achieved, fuel oil jet timing, the fuel oil jet rule and the circulating fuel oil jet amount are more accurately controlled, the fuel oil economical efficiency and the emission performance of the diesel engine are improved.

Description

technical field [0001] The invention relates to an engine fuel injector, in particular to a common rail fuel injection system controlled by double solenoid valves for a marine low-speed diesel engine, and belongs to the technical field of diesel engines. Background technique [0002] The common rail fuel injection system for diesel engines can realize precise and flexible control of fuel injection timing and cycle fuel injection volume, and is an effective means for high-power marine diesel engines to achieve high fuel economy and low harmful emissions. A pressure-accumulating medium-pressure common rail fuel injection system developed by Caterpillar uses a two-position three-way solenoid valve to control the movement of the booster piston, which realizes the mutual independence of fuel injection pressure and engine speed, but the process of fuel boosting And the fuel injection process is still interrelated and cannot be independent of each other, so multiple injections cann...

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Problems solved by technology

But its shortcoming is that this patent is the same as patents CN 102022241A and CN 102705121A. It realizes the control of the movement of the booster piston through the control of fuel drain and oil filling in the control chamber under the small head of the booster piston, thereby Complete the fuel pressurization process and the oil suction process, however, this control method for the movement of the booster piston requires precise matching of the oil inlet orifice and the oil discharge orifice on the control chamber, which will inevitably lead to increased processing costs and difficulty in manufacturing increase, and because the upper part of the booster piston always has high-pressure fuel, when the booster piston resets upward, due to the downward force generated by the high-pressure fuel, the booster piston is difficult to reset quickly, which will significantly reduce the effective filling time , which limits the coverage of diesel engine power

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