One of the main objectives of #HugYourEngine is to shine a spotlight on individuals who are helping make internal combustion engines cleaner and more efficient. This spotlight is on Robert McCormick.
Bob McCormick is a senior research fellow and platform leader for advanced biofuels and combustion research and development in fuels performance at NREL. He is also an SAE Fellow. His research is focused on end-use issues and fuel-engine interactions with alternative fuels, primarily biofuels—including ethanol and biodiesel, as well as next generation and futuristic fuels. A hallmark of his work is the application of foundational chemistry principles to the understanding of fuel-engine interactions and setting of ASTM fuel quality standards. His research has included studies on biodiesel chemistry effects that led to the development of ASTM fuel quality standards and research into oxygenate chemical structure effects on gasoline properties, spark-ignition engine efficiency, and emissions. Breakthrough work by McCormick's research team on how heating and cooling cycles affect the cold weather performance of biodiesel continues to serve as a foundation for low-cost solutions to cold weather problems. The studies have contributed to dramatic improvements in the quality of biodiesel and in the size of the biodiesel market in the United States, which has grown from less than 50 million gallons in 2004 to nearly two billion gallons in 2015. In addition, McCormick has contributed to the development and expansion of markets for ethanol, the most-used low-carbon transportation fuel worldwide.
Kelly Senecal (KS): When and why did you get started in combustion research?
Robert McCormick (RM): After obtaining my PhD in chemical engineering, I worked for almost 7 years for a Fortune 500 corporation doing research primarily on coal conversion (pyrolysis and gasification). In a shortsighted move, this company closed its R&D lab and laid off the staff. I was the PI on a DOE funded project to explore catalysts for methane conversion and was able to take this contract to the Colorado School of Mines and set myself up as a Research Professor. This is a cool job, but you only get paid if you have research funding. My DOE project could only support me part time. There was another professor who had just built a heavy-duty engine emissions test laboratory (engine dynamometer laboratory) who had funding and needed some help. I had always been interested in air pollution, so I joined his team. This was in 1994.
Emissions research involves making careful measurements of what is going in and out of the engine – chemical species, heat, and work – much like a chemical engineering pilot plant. Except that the chemical reactor – the engine – has varying volume, pressure, and temperature combined with rapid and highly exothermic reactions! A bit more complex than the reactors I studied in graduate school. Nevertheless, we were successful at revealing some important aspects of how fuel chemical composition affected diesel engine pollutant emissions, especially for oxygenates such as biodiesel. We also performed foundational work on emissions from natural gas fueled heavy-duty engines and vehicles. Many would not really call this combustion research because the engine itself is almost treated as a black box – the OEM calibration was left unchanged and the focus was on how introducing a new fuel into the market would impact emissions from existing engines.
In 2001 I decided I needed a real job – and was lucky enough to move to the the National Renewable Energy Laboratory. I continued to be involved in emissions research, but also many other aspects of fuel properties and chemistry such as oxidation stability in storage, diesel fuel cold temperature operability, and many other areas. Only in recent years have we expanded into what others might consider to be combustion research – working with single cylinder engines equipped with high speed pressure transducers and other instrumentation that is not very common in an emission test cell.
KS: What are you working on now?
RM: My team's primary focus today is the USDOE’s Fuel-Engine Co-Optimization project. This involves work with spark-ignition engines, diesel engines, and advanced compression ignition engines (for example, homogeneous charge compression ignition). The project seeks to identify fuel chemistries that allow optimal engine operation from an efficiency and emissions perspective, and furthermore to optimize fuel chemical structure and engine design/operating strategy in tandem.
KS: Describe your lab facilities.
RM: At NREL we have a fuel chemistry laboratory where we measure many fuel properties as well as detailed chemical composition for gasoline range fuels. Properties we measure include vapor pressure, heating value, cloud point, cold soak filterability, filter blocking tendency, acid number, peroxide content, and heat of vaporization. The lab also has constant volume combustion experiments for predicting cetane number and for combustion kinetics studies, a laminar flow reactor for autoignition and soot precursor formation mechanism and kinetics studies, as well as a differential scanning calorimeter/thermogravimetric analyzer coupled to a high-resolution mass spectrometer for studying gasoline evaporation and other problems.
Our engine and vehicle research laboratory has a single cylinder engine test cell with two engines – one on each end of a common dyno. One is a direct injection spark ignition engine, the other is a diesel engine that we are modifying to conduct advanced compression ignition research. We also have a larger dynamometer for multicylinder engines and FTP-style emissions studies. This is commonly used for diesel, natural gas, and propane engines. Finally, we have a heavy-duty chassis dynamometer where we conduct emissions, fuel economy, and vehicle performance studies on a broad range of heavy-duty vehicle technologies including diesel, natural gas, hybrid electric, full electric, and fuel cell powered vehicles.
KS: What’s your favorite type of flame?
RM: A diesel spray flame, the physics are so complex – turbulent, multiphase, mixing controlled reaction rates, large gradients in temperature and composition, chemical reactions producing a lot of heat, radiant heat transfer matters. What’s not to like?
KS: What’s your favorite fuel?
RM: Biodiesel! Relatively easy and low cost to make, high sustainability in terms of life-cycle GHG emissions reduction.
KS: What advice would you give students thinking about going into combustion research?
RM: Be as interdisciplinary as possible. Get degrees in chemistry and mechanical engineering (as an extreme example). Important outstanding problems are at the interface of different traditional fields of study.
KS: Is the IC Engine dead?
RM: No. But we are in the middle of a major transition. Personal cars are likely to become largely hybrid electric over the next decade – with an engine that is somewhat different than today’s engines. The IC engine will remain even more important in the heavy-duty on-road and off-highway markets – but will continue to evolve to meet even more strict emission standards.
KS: How is your work helping improve fuel efficiency or reduce emissions?
RM: We have worked to improve our understanding of how the fuel’s octane number, octane sensitivity, and heat of vaporization can be leveraged to design more efficient spark ignition engines. We have also worked to reveal the mechanism by which fuels blend non-linearly and synergistically for octane number – potentially pointing the way to blending higher octane number fuels. In diesel combustion, we are working to identify low-net-carbon bio-derived blendstocks that can be blended into conventional diesel and significantly lower engine-out emissions.