Fuel injection systems for internal combustion engines

Claim 1

A FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES COMPRISING AT LEAST ONE ELECTROMAGNETICALLY OPERATED FUEL INJECTION VALVE, A CONTROL CIRCUIT PRODUCING ELECTRICAL PULSES FOR ENERGIZING SAID AT LEAST ONE INJECTION VALVE, SO THAT SAID VALVE IS OPENED FOR A PERIOD DEPENDING ON THE DURATION OF EACH OF THE PULSES TO PASS FUEL TO THE ENGINE SAID CONTROL CIRCUIT COMPRISING A TIMING CIRCUIT CONSISTING ONLY OF COMPONENTS HAVING VALUES WHICH ARE INVARIABLE DURING THE OPERATION OF THE SYSTEM AND MEANS FOR FEEDING SAID TIMING CIRCUIT WITH AT LEAST ONE VARIABLE VOLTAGE WHICH VARIES AS A FUNCTION OF AT LEAST ONE PARAMETER OF ENGINE OPERATION TO CONTROL THE DURATION OF THE OUTPUT PULSES FED TO ENERGIZE SAID AT LEAST ONE INJECTION VALVE AND WHEREIN AT LEAST ONE VARIABLE VOLTAGE FED TO THE TIMING CIRCUIT IS DERIVED FROM A COMPUTER DEVICE, INDEPENDENT OF THE CONTROL CIRCUIT AND COMPRISING A PLURALITY OF VARIABLE RESISTANCE DEVICES CONNECTED ACROSS A VOLTAGE SUPPLY, AND MEANS FOR RESPECTIVELY VARYING SAID RESISTANCE DEVICES IN RESPONSE TO DIFFERENT OF ENGINE OPERATION.