US 7,607,422 B2 · Methods of flexible fuel engine conversions

Abstract

Methods and apparatus are disclosed for converting and optimizing the fuel system of an internal combustion engine in a pre-existing (used) vehicle to be fuel flexible and thus to operate on a mixture of fuels (like ethanol and gasoline) from a single fuel tank. The conversion includes adding a fuel composition sensor installed in the fuel line and/or adding an exhaust gas oxygen sensor installed in the engine's exhaust in addition to adding an electronic control unit with at least one fuel injector driver circuit for controlling an output signal to at least one fuel injector for controlling the air to fuel ratio of the engine. The electronic control unit can control both engine ignition timing and the air to fuel ratio of the engine based upon the composition of fuel mixture in the fuel tank. The electronic control unit can also control other aspects of engine operation like intake manifold boost for those engines that have turbo or superchargers.

Claims27

Dependent claims

An apparatus converting an OEM type engine having an OEM type of fuel system and exhaust system using an OEM type recommended fuel fed to the engine from an OEM type fuel tank, the apparatus comprising:

varying proportions of an alternate fuel being mixed with the OEM recommended fuel in the OEM type fuel tank to form a varying fuel mixture;
a sensor added to detect the proportional amount of alternative fuel in the fuel mixture being fed to the OEM fuel system from the OEM fuel tank, the sensor being selected from a group consisting of:
a) an exhaust gas O2 sensor;
and
b) a fuel composition sensor;
a fuel injector driver circuit added to the OEM type engine to control an output signal to a fuel injector;
an electronic control unit added to the OEM type engine to control the fuel injector driver circuit, the electronic control unit being arranged to receive an input signal from the sensor;
and
the electronic control unit being arranged to change the output signal from the fuel injector driver circuit to the fuel injector to vary the amount of the fuel being metered into the OEM type engine to control the engine's operating condition to maintain a correct air-to-fuel ratio needed for proper combustion of the fuel mixture fed from the OEM fuel tank.

6 more elements

A method of converting OEM type engine using an OEM type recommended fuel fed to the engine from an OEM type fuel tank, the method comprising:

varying proportions of an alternate fuel being mixed with the OEM recommended fuel in the OEM type fuel tank to form a varying fuel mixture;
adding a sensor to detect the proportional amount of alternative fuel in the fuel mixture being fed to the OEM fuel system to the OEM fuel tank selected from a group consisting of:
a) an exhaust gas O2 sensor;
and
b) a fuel composition sensor;
adding a fuel injector driver circuit to control an output signal to a fuel injector;
providing an electronic control unit controlling the fuel injector driver circuit and receiving an input signal from the sensor;
and
arranging the electronic control unit to change the output signal from the fuel injector driver circuit to the fuel injector to vary the amount of the fuel being metered into the OEM type engine to control the engine's operating condition to maintain a correct air-to-fuel ratio needed for proper combustion of the mixed fuel fed from the OEM fuel tank.

6 more elements

Dependencies are inferred from the claim text.

Methods of flexible fuel engine conversions

Life of this patent

Methods of flexible fuel engine conversions

Life of this patent

Abstract

Claims27