Fuel systems for compression ignition engines

Claim 1

A fuel system for supplying a high quality liquid fuel and a fuel of lower quality to a compression ignition engine having combustion spaces, comprising: a plurality of fuel injection nozzles for directing the high quality liquid fuel directly to the combustion spaces of the engine respectively, a fuel pumping apparatus connected to said injection nozzles for supplying the high quality fuel to the injection nozzles in turn and in timed relationship with the engine, said fuel pumping apparatus including a control means for adjusting the quantity of high quality fuel supplied to the combustion spaces and timing means for adjusting the timing of delivery of said fuel, said timing means being operatively connected to the engine so as to be responsive to the speed of the associated engine and the quantity of said fuel supplied to the engine, whereby with increasing engine speed the timing is advanced and for a given speed, the timing of delivery is retarded as the quantity of fuel delivered increases, an adjustable throttle disposed in a conduit conveying air to the combustion spaces of the engine, means for adjusting the size of said throttle in accordance with the air flow through the conduit, a fuel jet disposed to allow low quality fuel to flow into the stream of air passing through said conduit a tapered needle adjustably mounted in said fuel jet, said needle being operatively connected to said throttle and said jet being adjustably mounted and operatively connected to said timing means, whereby the relative position of said needle and said jet is in part determined by the means which adjust the size of said throttle and in part by said timing means, and conduit means through which the low quality fuel is supplied to said jet.