Apparatus and method for converting conventionally fueled engines to operate on an alternative fuel

Apparatus for converting a conventionally fueled internal combustion engine to operate with an alternative fuel, the engine having an electronic control module which generates a control signal (t.sub.1) for output to a conventional fuel injector, the apparatus comprising:

• an alternative fuel introduction assembly including a housing having an interior chamber, an inlet passage in fluid communication with a source of alternative fuel, and an alternative fuel injector moveable between an open position adapted to place the interior chamber in fluid communication with the engine and a closed position adapted to seal the interior chamber from fluid communication with the engine;
• a temperature sensor adapted to measure the temperature of the alternative fuel and to generate an output signal (T.sub.1) indicative of the measured temperature;
• and
• an electronic translator in electrical contact with the alternative fuel introduction assembly, the temperature sensor, and the electronic control module, the electronic translator adapted to receive the control signal and the output signal, and to generate an intermediate alternative fuel injector base pulse width control signal (t.sub.2) in accordance with the energy content differential of conventional fuel and the alternative fuel according to the expression ##EQU12## and the electronic translator further adapted to adjust the intermediate control signal (t.sub.2) to a final alternative fuel injector control signal (t.sub.3) in accordance with the flow and operating characteristics of the alternative fuel injector, and to output the final alternative fuel injector control signal (t.sub.3) to the alternative fuel introduction assembly, the final alternative fuel injector control signal (t.sub.3) controlling the period of time the alternative fuel injector remains in the open position so as to meter the flow of the alternative fuel to the engine.

A method of converting a conventionally fueled internal combustion engine to operate with an alternative fuel, the engine having an electronic control module which generates a control signal to a conventional fuel injector, the method comprising:

• providing an alternative fuel introduction assembly having an alternative fuel injector, the alternative fuel injector movable between an open position adapted to supply the alternative fuel to the engine and a closed position adapted to seal the alternative fuel from the engine;
• providing a source of alternative fuel in fluid communication with the alternative fuel introduction assembly;
• measuring the temperature of the alternative fuel and generating an output signal indicative of the measured temperature;
• generating an intermediate alternative fuel injector control signal in response to the temperature of the alternative fuel (T.sub.1) and the energy content differential of conventional fuel and the alternative fuel;
• adjusting the intermediate alternative fuel injector control signal to a final alternative fuel injector control signal in accordance with the flow and operating characteristics of the alternative fuel injector;
• and
• transmitting the final alternative fuel injector control signal to the alternative fuel introduction assembly to control the movement of the alternative fuel injector.