Abstract: A pressure regulator includes a valve, mechanical advantage device, actuator, controller and pressure sensor. The valve is disposed between an inlet port and an outlet port. The valve includes a pintle and seat. An actuator is provided to move the pintle away from the seat to allow the flow of gas from the inlet port to the outlet port and a pintle return spring is provided to bias the pintle towards seat. The actuator is configured to move the pintle in response to the magnitude of a control signal. A control system is provided to receive a gas pressure signal from a pressure transducer at the outlet port which detects the gas pressure at the outlet port and generate a control signal having a magnitude proportional to the detected gas pressure.

Abstract: An adaptor for adapting a seat of an engine capable of using a first fuel and having a seat for receiving a first fuel injector means with a discharge nozzle for flowing the first fuel, comprising a body having a bore with side walls for receiving the first fuel injector means, a plurality of spaced apart protuberances extending from the sidewalls for limiting movement of the discharge nozzle, an inlet for receiving a second fuel, and an adaptor hole for communicating with the discharge nozzle and the inlet, the adaptor hole being formed through a portion of the body which is to be fitted within the seat of the engine originally provided for receiving the first fuel injector means. The adaptor can be used to modify an existing engine using the first fuel such that the engine can use both the first fuel and a second fuel.