Hydrogen fuel injection

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Hydrogen fuel injection, or HFI, is a system to reduce exhaust emissions of internal combustion engines and improve fuel economy. HFI systems work by injecting hydrogen as a combustion enhancement into the intake manifold of an internal combustion engine to achieve these benefits. A small amount of hydrogen added to the intake air-fuel charge enhances the flame velocity and thus permits the engine to operate with leaner air-to-fuel mixture than otherwise possible. The result is lower pollution with more power and better mileage.

A simplified single-step combustion reaction is represented as: [FUEL] + [HYDROGEN] + [AIR] -> HC + CO + CO₂ + H₂O + NOx

For incomplete combustion, the above results in exhaust products including unburned hydrocarbons (HC) and carbon monoxide (CO). The NOx is formed mainly from the combustion air, and is highly temperature-dependent.

In 1974 John Houseman and D.J Cerini of the Jet Propulsion Laboratory, California Institute of Technology produced a report for the Society of Automotive Engineers entitled "On-Board Hydrogen Generator for a Partial Hydrogen Injection Internal Combustion Engine". In the same year, F.W. Hoehn and M.W. Dowy, also of the Jet Propulsion Lab, prepared a report for the 9th Intersociety Energy Conversion Engineering Conference, entitled "Feasibility Demonstration of a Road Vehicle Fueled with Hydrogen Enriched Gasoline." This research utilized onboard storage tanks to supply the hydrogen combustion enhancement.

More recent investigations have highlighted the potential for pollutant reduction. Research performed by scientists at the University of Birmingham, United Kingdom, released a study in June of 1995 at the HYPOTHESIS Conference at the University of Cassino, Italy in which it was presented that "hydrogen, when used as a fractional additive at extreme lean engine operation, yields benefits in improved combustion stability and reduced nitrogen oxides and hydrocarbon emissions." Similar results have been presented by a team of scientists representing the Department of Energy Engineering, Zhejiang University, China in the Spring of 1997 at an international conference held by the University of Calgary. Practical tests have been performed by California Environmental Engineering (CEE), The American Hydrogen Association Test Lab and Corrections Canada in which reduction in toxic exhaust emissions and fuel consumption were realized.

Commercially, Canadian Hydrogen Energy Company, LTD, produces an HFI system which generates hydrogen during vehicle operation by electrolyzing water (from an onboard storage tank) using power from the vehicle's electrical system. In dynamometer tests with 1992 60 series diesel engine fueled by low-sulphur (<15 PPM) diesel fuel, the system draws a maximum of 35 amps (12V DC) and yields 4.44% reduced fuel consumption, 6.17% reduced HC emissions, 0.39% reduces CO emissions, 4.34% reduced NOx emissions, and 7.0% reduced PM (particulate matter) emissions.

Publicly, Canadian Eagle Research Company produces the HyZor on-board electrolyzer that is comparable to coexisting commercial devices primarily being scaled down to fit Sedans, Coupes, SUV's, and Hybrids. A unique feature of the system is its design not to remove oxygen giving the output gas properties extremely similar to the HFI system while eliminating the required ducting components necessary to separate oxygen. These systems are fully automated only requiring occasional refills of distilled water when the system informs the driver by dash mounted led’s controlled by an electronic circuit integrated with the vehicles ignition.