This invention relates to an internal combustion engine of the fuel injection type and more particularly to an improved induction system for such an engine.
It is well known that the idle and low speed running conditions of an internal combustion engine offer the most difficult phase in which to control fuel economy and exhaust emissions. Although fuel injection systems have been proposed as a possible solution to this problem, the systems heretofore known have not completely solved the problems of low speed running. Specifically, the fuel injection nozzle discharges at a relatively high pressure. At low speeds the air is flowing very slowly through the induction system and the likelihood of wetting of the induction system passages is extremely great. Of course, if the liquid fuel impinges on the induction system passages poor running results, which is normally compensated for by providing an over-rich mixture under this condition. In addition to adversely affecting fuel economy, the use of such over-rich mixtures aggravates the problem of exhaust emission control.
It is, therefore, a principal object of this invention to provide an improved fuel injected internal combustion engine that offers significant improvements in performance at low speeds.
It is another object of the invention to provide an induction system for a fuel injected internal combustion engine that minimizes the likelihood of fuel condensation at low speeds.