A Combustion Control Method for Dual Fuel Engines Based on Reactivity Control

Abstract

The purpose of the present invention is to provide a combustion control method for a stratified combustion natural gas-diesel dual-fuel engine based on reactive activity control, which adopts a single injection of gas at small loads, multiple injection strategies under medium loads, and adopts a strategy of multiple injections under high loads. Gas single injection strategy, and flexibly adjust gas injection timing and injection amount according to different loads. The pre-mixing of diesel fuel is realized by the large advance angle injection of diesel, and the active components are formed in the cylinder during the compression process, and the ignition starting point is controlled by the pilot diesel injection, so as to realize the stratified combustion of dual-fuel engine based on chemical reaction kinetic activity control Strategy. According to the gas concentration distribution in the cylinder formed by the gas injection strategy under different loads, the matching of diesel injection timing and injection quantity is carried out reasonably, and a reasonable fuel-gas coupling stratification is formed in the cylinder to achieve optimal in-cylinder combustion under different loads. Therefore, the engine can achieve efficient, stable and low-emission combustion.

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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