Engine exhaust emission regulations are becoming increasingly restrictive. One way in which the stricter emission standards can be met is to tailor the rate, or rate-shape the quantity and timing of the fuel injected into the combustion chamber to match the engine cycle. The ability to match the desired fuel/air ratio can result in reduced levels of particulate and oxides of nitrogen in the engine exhaust.
A second problem which rate-shaping improves is engine noise. By injecting the fuel slower during the early phase of the combustion process, combustion is less harsh which results in less engine noise. The present invention is directed to overcome one or more of the problems as set forth above.