Optimising fuels and engines to boost efficiency and performance

Part of Today in the Lab – Tomorrow in Energy?

Today in the Lab – Tomorrow in Energy? shines a spotlight on research projects under development in the Technology Collaboration Programmes (TCPs). Learn more about the initiative, read the launch commentary, or explore the TCPs.

Enabling the emergence of a new generation of cars and trucks

What is the aim of this project?

The Co-Optima initiative aims to enable the emergence of a new generation of cars and trucks that use more sustainable fuels, with greater fuel efficiency and fewer pollutant emissions. The initiative does this by expanding the science base that industry needs to simultaneously improve both fuels and combustion engines.

How could this technology be explained to a high school student?

One part of the Co-Optima project is focusing on very lean operation of spark-ignition fuels and engines – that is, burning less fuel in a given amount of air than in a conventional spark-ignition engine. Lean operation can improve fuel-conversion efficiency – the amount of power obtained from the fuel – and reduce CO2 emissions.

What is the value of this project for society?

  • improves vehicle fuel economy
  • reduces CO2 emissions
  • determines how fuels should be designed to enable more efficient engines
  • enables more and better use of biofuels

At what stage of development is this project?

The Co-Optima initiative began in 2015 and is expected to run until September 2021. The initial phase focused on gasoline-like fuel effects on conventional spark-ignition engines. Summary results have been presented in a journal article. The next phase focuses on fuel effects on lean combustion in a multimode spark-ignition engine – an engine that combines conventional combustion for peak power with lean combustion for lower loads, which are more frequent. Current efforts are highlighted in the latest Co-Optima Year in Review report.

What government policies could bring this from the lab to the market?

  • promoting research, development and demonstration to speed development of lean combustion systems and lean exhaust gas aftertreatment
  • implementing regulations on greenhouse gas emissions based on analysis of full vehicle and fuel life cycles

Liquid fuel spray, fuel vapour penetration and flame development in an engine that uses partial fuel stratification to stabilise overall lean operation. Information from such research is critical for optimising fuels and engines at the same time. (ST = Spark Timing). Credit: Magnus Sjöberg, Sandia National Laboratories

Partners and funders


  • US Department of Energy
  • Sandia National Laboratories and several other US national laboratories


The project is funded by the US Department of Energy.

Learn more

About the Technology Collaboration Programme on Clean and Efficient Combustion (Combustion TCP)

The Combustion TCP provides a forum for interdisciplinary exchange and enables international research collaboration to advance the understanding of combustion processes. In this way it accelerates the development of combustion technologies with lower fuel consumption and pollutant emissions in transport, power generation, industry and buildings. The Combustion TCP generates, compiles and disseminates independent information, expertise and knowledge related to combustion for the research community, industry, policy makers and society.

Contact: dlsiebers1@gmail.com