Engines: US National Labs host several single- and multi-cylinder research engines for light-duty (LD), medium-duty (MD) and heavy-duty (HD) applications. The engines typically employ direct injection (DI) using modern fuel-injection hardware, and some enable optical access to the combustion chamber.

Fuels: Liquid fuels with fuel properties well outside those of commercial gasoline and diesel fuels can be accommodated. This includes wide ranges of bio-based blendstocks.

Combustion modes: Conventional stoichiometric spark-ignition (SI) and diesel combustion, as well as advanced lean/dilute low-temperature combustion (LTC) for higher efficiency and/or low engine-out NO_x.

All-metal engine measurements: Performance studies of fuel effects on combustion, engine performance and thermal efficiency (fuel economy), as well as exhaust emissions of regulated pollutants such as unburned hydrocarbons (UHC), carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxides (NO_x), and particulate matter (PM). This includes the assessment of fuel effects on the performance of exhaust aftertreatment devices.

Optical engines: Relevant for both LD SI gasoline and HD diesel applications. These enable identification of in-cylinder processes that may be adversely or positively affected by the use of non-conventional fuel blendstocks. Measurement include visualization of fuel sprays, in-cylinder fuel/air mixing, combustion, and pollutant formation.

The engines are well instrumented and feature precise intake charge handling (temperature, pressure and composition), as well as coolant and oil temperature control. Engine controls allow full flexibility in terms of fuel-injection schedules and spark timing. All engines are installed in test cells or labs and coupled to electric motors that control engine speed and absorb engine output power.

State-of-the-art optical engines enable high-speed laser and other optical measurements of in-cylinder processes, providing both conceptual understanding as well as validation data for CFD models.

A uniquely instrumented gasoline octane rating CFR engine, the engine used in the ASTM RON and MON octane tests, is a part of the research engine portfolio. In addition, a new MD Advanced Fuels Research Single Cylinder Engine (AFR-SCE) allows fuels-focused combustion studies that link fuel properties to engine performance.