Engine combustion control via fuel reactivity stratification

摘要

A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

主权项

1. A compression ignition combustion method for an internal combustion engine wherein:
a. the engine has a combustion chamber containing an at least substantially homogeneous mixture of fuel and air distributed throughout the combustion chamber; b. the method includes the steps of:
(1) supplying a fuel charge into the combustion chamber, wherein the reactivity of the fuel charge differs from the reactivity of the fuel within the fuel and air mixture; and(2) compressing the fuel and air mixture:
i. before the fuel charge significantly disperses within the combustion chamber, whereby the combustion chamber has a stratified distribution of fuel reactivity such that the fuel charge defines a volume within the combustion chamber having different reactivity than the remainder of the combustion chamber,ii. until ignition occurs within the combustion chamber,thereby causing combustion of the fuel charge and the fuel and air mixture.