34402 results about "Combustion chamber" patented technology

A variety of methods and arrangements for improving the fuel efficiency of internal combustion engines are described. Generally, selected combustion events are skipped during operation of the internal combustion engine so that other working cycles can operate at a better thermodynamic efficiency. In one aspect of the invention, an engine is controlled to operate in a variable displacement mode. In the variable displacement mode, fuel is not delivered to the working chambers (e.g. cylinders) during selected “skipped” working cycles. During active (“non-skipped”) working cycles, a maximum (e.g., unthrottled) amount of air and an optimized amount of fuel is delivered to the relevant working chambers so that the fired working chambers can operate at efficiencies closer to their optimal efficiency. A controller is used to dynamically determine the chamber firings required to provide the engine torque based on the engine's current operational state and conditions. The chamber firings may be sequenced in real time or in near real time in a manner that helps reduce undesirable vibrations of the engine.

In an internal combustion engine that can burn two fuels, the main fuel may become unavailable, either temporarily or until the main fuel is replenished. The present apparatus determines when to fuel an engine with main fuel and secondary fuel, or secondary fuel alone. The apparatus includes a main-fuel supply system comprising a main-fuel injection valve that introduces main fuel into an engine combustion chamber; a secondary-fuel injection system comprising a secondary-fuel injection valve that introduces secondary fuel directly into the combustion chamber; a pressure sensor associated with the main-fuel supply system for determining injection pressure inside the main-fuel injection valve; and an electronic controller in communication with the pressure sensor and programmable to separately command actuation of the secondary-fuel and the main-fuel injection valve when injection pressure is greater than a predetermined threshold, and to otherwise command actuation of the secondary-fuel injection valve and not the main-fuel injection valve.

A fuel injection system includes a first fuel injector that injects a lower-octane fuel into a combustion chamber of an internal combustion engine, and a second fuel injector that injects a higher-octane fuel into an intake passage of the engine. When the engine temperature is equal to or lower than a predetermined temperature during a start-up period of the internal combustion engine, fuel having the lower octane is injected via the first injector while prohibiting injection of the higher octane fuel via the second fuel injector.