A FLEX-FUEL SENSOR AND CONTROL STRATEGY FOR VARIABLE CONCENTRATIONS OF HYDROGEN-NATURAL GAS BLEND FUEL IN AN INTERNAL COMBUSTION ENGINE

This paper proposes an ultrasonic sensor methodology to measure concentrations in a binary gaseous alternative fuel system of hydrogen and natural gas for automotive applications. Further, it proposes a sensing and control architecture that enables alternative fuel vehicles, in this case a series hybrid electric vehicle, to fuel and operate their conventional IC engines on variable concentrations of hydrogen and compressed natural gas (HCNG). This represents a new type of flex fueling capability namely Flex-HCNG. The proposed Flex-HCNG system includes the ability to refuel from any hydrogen or natural gas fueling station into a single high-pressure on-board storage tank and then to start and run under changing fuel concentrations. The benefits of Flex-HCNG will be greater demand for both natural gas and hydrogen by effectively increasing available fueling infrastructure and providing security through greater fuel choice. Increasing demand for hydrogen prior to widespread availability of fuel cell vehicles will facilitate faster transition to renewable hydrogen and natural gas economy.