Mixed fuel engine
AssigneeInnovative Fuel Systems Ltd.
InventorsPeter Staykov, Daniel Ivan Handford, Curtis Figley, Andrei Chichak
Life of this patent
Estimating the term…
Abstract
A system, method and circuit restricts the amount of a first fuel being provided to a duel-fuel engine, for example a diesel-natural gas engine; wherein a secondary circuit is provided, in parallel, to the circuit formed between the engine control unit, first fuel injector, and ground comprising a dummy load, and a normally closed switch inserted in the first fuel injection circuit; such that when the normally open switch is in a closed state the dummy load provides a resistance to the second sub-circuit, such that a total resistance in the second sub-circuit is equal to a total resistance in the first sub-circuit when the normally closed switch is in a closed state.
Claims23
A mixed-fuel control circuit comprising:
- an engine control unit that generates an injection signal and a fuel pump signal;
- a fuel pump in fluid communication with a primary fuel source and a primary fuel rail, the fuel pump delivering fuel from the primary fuel source to the primary fuel rail in response to a received pump signal from the engine control unit;
- a fuel injector in fluid communication with the primary fuel rail and a combustion engine, the fuel injector injecting fuel from the primary fuel rail into the combustion engine in response to a received injection signal;
- and
- a mixed-fuel control unit comprising:
- injector switches that selectively connect the engine control unit to a first sub-circuit and a second sub-circuit, the first sub-circuit comprising the fuel injector and a second sub-circuit comprising a dummy load;
- and
- pump switches that control an amount of fuel that is delivered from the primary fuel source to the primary fuel rail;
- wherein the mixed-fuel control unit is configured to:
- switch between the first sub-circuit and the second sub-circuit such that a squelched portion of the injection signal is conducted through the second sub-circuit instead of the first sub-circuit and the received injection signal comprises a non-squelched portion of the injection signal;
- and
- control the pump switches to reduce the amount of fuel that is delivered from the primary fuel source to the primary fuel rail based on the squelched portion of the received injection signal.
A method of controlling delivery of fuel to a mixed-fuel engine, the mixed-fuel engine comprising an engine control unit, a fuel injector that injects fuel from a primary fuel rail into the mixed-fuel engine in response to a received injection signal from the engine control unit, and a mixed-fuel control unit comprising a first sub-circuit comprising the fuel injector and a second sub-circuit comprising a dummy load, the method comprising the steps of:
- controlling an amount of primary fuel injected into the mixed-fuel engine from the primary fuel rail by switching between the first sub-circuit and the second sub-circuit such that a squelched portion of the received injection signal is conducted through the second sub-circuit instead of the first sub-circuit, the received injection signal comprises a non-squelched portion of the injection signal;
- and
- maintaining a primary fuel rail pressure by reducing the amount of primary fuel delivered to the primary fuel rail from a primary fuel source based on the squelched portion of the received injection signal.
A method of converting an engine to a mixed-fuel engine, the engine comprising an engine control unit that generates an injection signal and an injector that injects fuel from a primary fuel rail into the engine in response to a received injection signal, the method comprising the steps of:
- connecting the engine control unit to a first sub-circuit that comprises an injector and a second sub-circuit that comprises a dummy load, the dummy load being connected in parallel with the injector;
- providing a mixed-fuel controller that:
- controls an amount of primary fuel injected into the mixed-fuel engine from a primary fuel rail by switching between the first sub-circuit and the second sub-circuit such that a squelched portion of the injection signal is conducted through the second sub-circuit instead of the first sub-circuit, the received injection signal comprises a non-squelched portion of the injection signal;
- and
- reduces an amount of primary fuel delivered to the primary fuel rail from the primary fuel source based on the squelched portion of the injection signal.
Dependencies are inferred from the claim text.