Natural gas supply system for electric control natural gas engine

Abstract

The invention provides a technical proposal of a natural gas supply system used in an electrically controlled natural gas engine. The natural gas supply system comprises a natural gas tank, an on-off electromagnetic valve and a reducing valve which are in gas connection in turn, and leads natural gas in an engine intake manifold through a natural gas lead-in device, wherein a small gas tank which can stabilize pressure is arranged between the reducing valve and the natural gas lead-in device, so as to ensure stable operation of a natural gas engine and an electronic control system of the natural gas engine. Moreover, the technical proposal further provides the following two operating systems of the electronically controlled natural gas engine: one is an economical type self-priming system; and the other is a direct-injection system with better performance, which can meet the emission requirements of automobiles and has excellent acceleration performance and high efficiency.

Description

technical field [0001] The invention belongs to the technical field of automotive electronics, and relates to an electronically controlled natural gas engine working system, in particular to its natural gas supply system. Background technique [0002] The main component of natural gas is CH4, which is a high-quality clean fuel. Natural gas can be used without complicated refining process and additives during production, so the price is cheap; the outstanding advantage of natural gas is that it burns completely and the exhaust gas is relatively clean, which can meet the needs of more and more The stricter emission regulations are beneficial to purify the environment. The greenhouse effect produced by the combustion of natural gas is 54% of that of petroleum. After combustion, there is basically no smoke and dust, and other toxic emissions are also the least. [0003] With the development of automotive electronic control technology, the current natural gas engine basically ado...

AI Technical Summary

Problems solved by technology

There are two types of regulating valves, one is a manual regulating valve, which cannot be changed during operation after one-time adjustment, because the air intake volume changes greatly under different working conditions when the vehicle is running, and the natural gas entering through the fixed valve cannot It is adjusted with the intake air volume, so that only a suitable "air-fuel ratio" can be formed at a certain point. In most working conditions, it is either too lean or too rich, and the gas consumption, power, and emissions are not good.

The other is to use an electronic regulating valve to control the flow, but because the inertia of the regulating valve cannot follow the change of the throttle opening in time, and because of the change of the negative pressure of the intake manifold (the negative pressure varies with the engine speed and the throttle opening The change of two variables) is not detected, and the pressure formed at the outlet of the regulating valve is constantly changing and unknown, which will cause inaccurate control of the natural gas intake, so the air-fuel ratio cannot be well controlled, and the control effect is not good.

[0007] 2. Injection type: When it is used to transform the EFI gasoline engine, the original gasoline EFI control system remains basically unchanged, and an electromagnetic injection valve is connected to each intake manifold of the engine, and the natural gas is decompressed by the decompression valve The injection quantity of gas is controlled by the added solenoid valve, and the signal of the original electronic injection unit (ECU) controlling the fuel injector is linearly extended through a control unit to control the solenoid valve. Although this scheme is operated by the original ECU through the sensor pair of the system The optimal fuel injection quantity can be obtained through state detection, but the optimal air-fuel ratio of a gasoline engine is different from that of natural gas, and the fuels with the same calorific value of natural gas and gasoline have different operating states on the engine, so this The control of natural gas intake volume by this method is also inaccurate

However, since the flow regulating valve or injector works in a pulse mode, that is, the nozzle is switched on and off periodically, the response of the pressure reducing valve cannot be very fast, and the volume of the pipeline from the pressure reducing valve to the nozzle rail is very small, and the injection process will inevitably cause Large fluctuations in the natural gas pressure at the inlet end of the injection rail affect the stability of the working system of the electronically controlled natural gas engine

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