Positioned for the Future

Internal combustion engines are the foundation of the global economy. They provide the mobility, the power and means for people and economies to thrive and grow.

They are diverse in size and configuration, the kinds of fuels they can use, and the work they can perform. From small engines of only a few horsepower, to the largest engines of several thousand horsepower, the internal combustion engine is a marvel of invention, innovation, and continuous improvement.

Nowhere has progress been more evident than the internal combustion engine’s relationship with the environment. Emissions from new internal combustion engines have declined to near zero levels over the last decade.

With efforts increasingly focused on reducing carbon emissions, the future of the internal combustion engine and the fuels that it uses comes clearer into focus. Decarbonizing the economy will take time and require many different types of solutions for different sectors.

How are Internal Combustion Engines Positioned for the future? 

Internal combustion engines (ICE) are a technology known for continuous improvement, and future milestones are already in place. By making changes to the types of fuels used in internal combustion engines, immediate progress can be made in lowering greenhouse gas and other emissions. New engine designs and architectures are also being introduced.

Manufacturers Continue to Improve Efficiency and Lower Emissions in Future ICE Products

Both the U.S. Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) have proposed new rules that impact future light-duty passenger vehicles, SUVs, and pickup trucks powered by internal combustion engines.

NHTSA recently proposed new CAFE standards for passenger cars and light trucks built in model years 2027-2032, and new fuel efficiency standards for heavy-duty pickup trucks and vans built in model years 2030-2035. If finalized, the proposal would require an industry fleet-wide average of approximately 58 miles per gallon for passenger cars and light trucks in MY 2032, by increasing fuel economy by 2% year over year for passenger cars and by 4% year over year for light trucks. For heavy-duty pickup trucks and vans, the proposal would increase fuel efficiency by 10% year over year.

EPA announced on April 12, 2023, more ambitious proposed standards to further reduce harmful air pollutant emissions from light-duty and medium-duty vehicles starting with model year 2027. The proposal builds upon EPA’s final standards for federal greenhouse gas emissions standards for passenger cars and light trucks for model years 2023 through 2026 and leverages advances in clean car technology to unlock benefits to Americans ranging from reducing climate pollution, to improving public health, to saving drivers money through reduced fuel and maintenance costs. The proposed standards would phase in over model years 2027 through 2032.

For heavy-duty commercial trucks, the EPA adopted a final rule, “Control of Air Pollution from New Motor Vehicles: Heavy-Duty Engine and Vehicle Standards,” on December 20, 2022. It sets stronger emissions standards to further reduce air pollution, including pollutants that create ozone and particulate matter, from heavy-duty vehicles and engines starting in model year 2027.   

ICEs Can Be Sustainable by Changing the Fuel Used in the Population of ICE Vehicles, Engines, and Equipment

In the meantime, accelerating the turnover of the existing truck fleet, continued improvement of internal combustion engines, and utilizing low-carbon renewable fuels is just as important as a zero-emission vehicle approach to help achieve meaningful progress toward climate goals

With an expansive population of vehicles, engines, and equipment in use around the world, the opportunity to reduce emissions by simply changing fuel types is significant. Using renewable low carbon biofuels offers an immediate and proven way to reduce greenhouse gas and other emissions by 50% - 80 % across the entire vehicle population, limited only by the supply of renewable fuel.

For spark-ignited Internal combustion engines that traditionally use gasoline, fuel blends in the U.S. incorporate ethanol to reduce emissions, particularly during summer months to help combat formation of smog. In the U.S. there are 187 plants that produce ethanol; nearly 18 million gallons were produced in 2022. More than four-fifths of all biofuel production in the US was for ethanol.

Diesel engines can use blends of biodiesel (B-5 to B20) without any modifications to engines or fueling infrastructure. Renewable diesel fuel is a drop-in replacement for petroleum diesel fuel in blends up to 100%. In the U.S., about 3.3 billion gallons of advanced renewable biodiesel fuels were produced in 2022. 

Superior Combination of Features and Supporting Infrastructure 

New fuels and technologies like battery electric and hydrogen are emerging with the promise of superior performance and cost savings to internal combustion engines. Today these new technologies make up a small fraction of the market and many in niche sectors. Availability of the new fuels is limited, along with limited real-world experience. As more experience is gained in coming years, more realistic, holistic comparisons can be made about performance and operating costs and the suitability and likelihood of displacing internal combustion engines in the market.

The population of hundreds of millions of internal combustion engines, vehicles and equipment is supported by a vast infrastructure of established servicing, parts, refueling and secondary sales markets spread across the economy and in every community in the U.S. Serious alternatives to ICEs will have to establish superior  performance well beyond the greenhouse gas emissions profile of the individual engine or vehicle and compete effectively in all these different areas.

For some applications particularly those in heavy equipment and machinery, and some types of vehicle applications powered by diesel engines, it is likely that no suitable or superior alternative to internal combustion engines will emerge in the foreseeable future. Economic considerations, limited market size, and technical roadblocks will likely ensure that internal combustion engines remain the prime technology for these sectors into the near future.

New Innovations in Internal Combustion Engines

Internal combustion engine architectures Inline configuration of cylinders (“I-6”) or V configurations (“V-8”) have endured for decades. New entrants are emerging in the markets for internal combustion engines that introduce new possibilities for improving efficiency of the engine, reduction in weight and greater power density. If successful, these new engine designs and strategies may transform internal combustion engines and the fuels they use in the future.