Controlling the fuel injection in a diesel engine

The invention relates to the Common Rail (CR) injection system for Diesel engines and proposes a device for measuring the instantaneous mass flow-rate in a high pressure liquid flow. A mass based feedback control logic is also proposed to guarantee the control on the quantity of fuel that is actually injected in the combustion chamber.

The device is installed on the pipe connecting the accumulator (rail) to the electro-injector in a Common Rail system in order to measure the flow that feeds the injector during the injection period. It is made of one or two piezoelectric transducers to evaluate the mass of fuel that enters the injector which is directly related to the fuel quantity, which is injected in the combustion chamber. In contrast with current methods, the result is a precise fuel measure that allows to directly control the injected quantity. There is an improvement of the combustion process and a consequent reduction of produced pollutants, especially PM10. The fuel mass at the injector inlet is monitored by the engine Electronic Control Unit and compared to a reference value in order to regulate the energizing time of the injectors and therefore the injected mass. The increased precision allows to perform more efficient multiple injection schedules. The system can be installed on new engines, but it is possible to retrofit old engines , even those already installed on vehicles.

Possible Applications

Light vehicles;
Heavy duty vehicles;
Static engines;
Diesel engines.


Better control on the injected mass;
Potential reduction of consumption;
Potential benefits on pollutants;
Feedback control of injected mass;
Quicker flow regulation during engine transients.


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