An investigation has been carried out on clean automotive technologies at the Southwest Research Institute. This is to allow traditional internal combustion (IC) engines to run effectively on hydrogen fuel.
Dr. Graham Conway, pictured here with a Hydrogen-fueled internal combustion engine, and colleagues Dr. Thomas E. Briggs, SwRI Staff Engineer, and Dr. Terry Alger, director of SwRI’s Automotive Propulsion Systems Department, recently ran simulations of four novel approaches for using spark-ignited combustion of hydrogen to fuel an IC engine. Image Credit: Southwest Research Institute.
Over the past few years, government and industry scientists sought techniques to transition transportation energy usage away from fuels that release carbon dioxide (CO2) - a greenhouse gas (GHG) that adds to climate change issues - to hydrogen and other alternative fuels that liberate less CO2 on a well-to-wheel basis. As per the US Environmental Protection Agency, transportation alone generated around 29% of total US GHG emissions in 2019, which is considered the biggest share.
The long-term goal of the researchers was to utilize hydrogen instead of diesel, natural gas and gasoline in IC engines. As a result of a high flame speed, hydrogen tends to burn well inside IC engines, and its special properties, like low ignition energy, pose engineering difficulties to be overcome.
Such properties encourage pre-ignition, a process at the time of which a mixture of air and fuel kindles in the unburned fuel. This will result in uncontrolled combustion and later damages the engine.
SwRI’s Powertrain Engineering Division is investigating possible solutions to such difficulties. This is inclusive of higher-efficiency methods to preexisting hydrogen IC engine ideas.
The belief is that automakers could utilize the enhanced hydrogen-fueled engines to transition from present CO2-emitting engines to the zero-emission future.
If we can adapt an existing IC engine design to burn hydrogen efficiently, then we have another option to reach zero CO2 emissions. An efficient hydrogen IC engine can give us that necessary zero- CO2 emission characteristic while also providing an economically-attractive solution to the transportation industry.
Dr. Thomas E. Briggs Jr, Staff Engineer, Southwest Research Institute
Recently, Briggs, Dr. Graham Conway, SwRI principal engineer and Dr. Terry Alger, director of SwRI’s Automotive Propulsion Systems Department, performed simulations of four novel methods for utilizing spark-ignited combustion of hydrogen to fuel an IC engine.
Briggs stated, “In the late 2000s, hydrogen IC engine development was being heavily funded by the U.S. Department of Energy and internally by a number of automakers. Our research builds upon some of the ideas that came about from that research period.”
Briggs felt that the study performed at that time illustrated a hydrogen-fueled SI engine that could obtain 45% brake thermal efficiency (BTE) in the laboratory. This was competitive with diesel engines at the time.
Normally, gasoline engines available at present have BTEs of 30–43% and modern diesel engines have BTE’s from 42 to 50%. By comparison, each of SwRI’s simulated methods displays a development path to obtain at least 50% BTE.
Higher brake thermal efficiency translates to lower fuel consumption. None of the simulations we completed represent fully optimized calibrations for a combustion system, but they all show thermal efficiencies comparable to a baseline diesel engine, with nitrogen oxides (NOx) emissions consistent with diesel combustion but no carbon monoxide, hydrocarbon, soot, or CO2 emissions. It is very promising.
Dr. Thomas E. Briggs Jr, Staff Engineer, Southwest Research Institute
Briggs, Conway and Alger recently got a patent for technology that enhances hydrogen fuel injection management. This improves air-fuel mixtures and reduces the threat of pre-ignition. The researchers are collaborating with engine suppliers to obtain a suitable fuel injector to shift into the second phase of their research.
SwRI is in a strong position to pick up the threads from previous hydrogen engine developments and improve on them. With a strong background in automotive engineering, emissions testing, and hydrogen energy research, we are well-positioned to lead a shift to cleaner hydrogen-fueled vehicles.
Dr. Thomas E. Briggs Jr, Staff Engineer, Southwest Research Institute
SwRI consists of a multidisciplinary team dedicated to hydrogen energy research initiatives for decarbonization technologies to be deployed throughout a wide spectrum of industries.