Describes an injection device comprising a centrally-located injection valve of the standard Diesel type together with one or more fuel-valves.
The cylinder head is arranged in some cases to permit of two compression spaces, the space situated in the annular chamber being the most convenient for the reception of the pump injection. The object of the invention is to greatly reduce the power absorbed by the air compressor, as well as to obviate the danger of mechanical trouble arising from the employment of compressed air only for the injection of an initial charge of fuel supplementary to a subsequent mechanically injected charge.
This preliminary injection takes place at the moment of highest compression and its combustion serves to ignite the subsequent charges, which are timed to occur at a period when the pressure within the cylinders has somewhat fallen. Force pumps of the type used in hot-bulb engines are used, the fuel being subjected to no pulverising action.