In-line type fuel pump with variable pre-travel as well as accurately-controlled SCR (selective catalyst reduction) system of in-line type fuel pump

Abstract

The invention relates to an in-line type fuel pump with a variable pre-travel as well as an accurately-controlled SCR (selective catalyst reduction) system of the in-line type fuel pump. The fuel pump comprises a fuel pump assembly and the SCR system, wherein a fuel pump body is connected with a pump body of a urea pump; a fuel pump cam shaft is connected with a urea pump cam shaft; a fuel pump pull rod is connected with a urea pump pull rod; the fuel pump is connected with the SCR system through the urea pump; a speed regulator of the fuel pump synchronously and accurately controls the fuel injection quantity of the fuel pump and the liquid spraying quantity of the urea pump according to the work condition of a diesel engine. The pump end pressure is increased by reducing the diameter of a plunger of the fuel pump; the content of CO (carbon monoxide), HC (hydrocarbon compounds) and especially NOx in tail gas of the diesel engine of the fuel pump with the variable pre-travel can be effectively reduced due to shape change of a work surface of the plunger; the urea pump synchronously and accurately controlled by the speed regulator can spray a urea solution matched with the content of NOx in the tail gas of the diesel engine at any time, and the urea solution can have a chemical reaction after entering an SCR box to further eliminate remaining NOx; the fuel consumption, the urea consumption and the fault rate of the diesel engine can be effectively reduced on the premise that exhaust emission meets a standard.

Description

technical field [0001] The invention relates to a fuel pump and an SCR system for a diesel engine, in particular to an in-line variable pre-stroke fuel pump and a precisely controlled SCR system. Background technique [0002] With the development of society, the traditional in-line fuel pump can no longer meet the emission standards of vehicle diesel engines. The "Opinions of the General Office of the State Council on Strengthening Energy Conservation and Emission Reduction in the Internal Combustion Engine Industry - National Law Office (2013) No. 12" requires: "...By 2015, all newly produced diesel engines for vehicles will use high-pressure fuel injection systems...", currently , almost all domestic automotive diesel engine manufacturers have used electronically controlled high-pressure fuel injection systems. [0003] The electronically controlled high-pressure fuel injection system developed by developed countries greatly reduces the smoke and particulate matter of the...

AI Technical Summary

Problems solved by technology

[0004] The unique structure of the electronically controlled high-pressure fuel injection system makes the high-pressure oil pump consume a lot of power of the diesel engine. The pre-injection of the electronically controlled high-pressure fuel injection system before the compression top dead center of the diesel engine increases the cylinder pressure of the diesel engine in advance and consumes additional power of the diesel engine. Raising the exhaust temperature of the diesel engine makes the electronically controlled SCR system work better. The electronically controlled high-pressure fuel injection system sometimes injects a little fuel before the exhaust valve of the diesel engine is about to open, which is the so-called post-injection, which causes waste. In addition, The electronically controlled high-pressure fuel injection system and the electronically controlled SCR system have complex structures, high cost, squeamish use methods, unsatisfactory starting and climbing performance, extreme dependence on clean fuel, and inconvenient maintenance services, which make users purchase , use, and maintenance costs are greatly increased and are not welcomed by users. Therefore, the electronic control system also has many shortcomings.

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