Natural gas-diesel dual-fuel layered combustion engine combustion control method based on reactivity control

Abstract

The invention aims to provide a natural gas-diesel dual-fuel layered combustion engine combustion control method based on reactivity control. Fuel gas single-time injection is adopted under the smallload, the multi-time injection strategy is adopted under the medium load, the fuel gas single-time injection strategy is adopted under the high load, and the timing and injection quantity of fuel gasinjection are flexibly adjusted according to the different loads. Diesel is pre-mixed through diesel large-advance-angle injection, active components are formed in a cylinder in the compression process, and the ignition starting point is controlled through ignition diesel injection, so that the dual-fuel engine layered combustion strategy based on chemical reaction kinetics activity control is achieved. According to fuel gas concentration distribution formed in the cylinder through the fuel gas injection strategies under the different loads, the timing and the injection quantity of diesel injection are reasonably matched, reasonable fuel oil and fuel gas coupling stratification is formed in the cylinder, and the optimal in-cylinder combustion effect is achieved under the different loads, so that efficient, stable and low-emission combustion of an engine is achieved.

Description

technical field [0001] The invention relates to an engine control method, in particular to a dual-fuel engine combustion control method. Background technique [0002] Due to its abundant reserves, clean combustion, and easy mixing with air and other physical and chemical properties, natural gas has become a new type of fuel to replace traditional fuels such as diesel and gasoline. [0003] In order to achieve clean, stable, and low-emission combustion of diesel-natural gas dual-fuel engines, low-temperature combustion technologies such as premixed compression ignition combustion (PCCI) and homogeneous compression ignition combustion (HCCI) have been widely studied and applied in recent years. However, PCCI and HCCI combustion methods mainly have problems such as difficult combustion control, difficulty in realizing high-load conditions, difficulty in cold start, and high CO and HC emissions. Existing natural gas engines mostly use single-point injection of gas in the intake...

AI Technical Summary

Problems solved by technology

However, the PCCI and HCCI combustion methods mainly have problems such as difficult combustion control, difficult to achieve high-load conditions, difficult cold start, and high CO and HC emissions.

Existing natural gas engines mostly adopt single-point injection of gas in the intake manifold, but there are technical defects such as lagging gas supply response and prone to scavenging backfire, and it is also difficult to achieve stratified combustion

In order to solve the above problems, it is necessary to provide a stratified combustion control method for natural gas / diesel dual-fuel engines based on reactivity control. The intake port multi-point injection system is used to form a reasonable natural gas concentration stratification in the cylinder. Rail diesel in-cylinder direct injection system realizes multiple injections, uses gas multiple injection strategy to form a reasonable gas concentration stratification in the cylinder that is conducive to the ignition of diesel components, and active reaction diesel injection + pilot diesel injection three injections The strategy realizes the combustion control of dual-fuel engines based on chemical reaction kinetic activity and pilot injection control, and adjusts the timing and injection quantity of gas injection, diesel active reaction diesel injection and pilot diesel injection by the electronic control system under different loads. Solve the problems of high HC and CO emissions, low engine efficiency, and cylinder knocking when expanding to high-load conditions under small and medium loads, so as to improve engine power performance

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