CLEERS (Crosscut Lean Exhaust Emissions Reduction Simulations) is an initiative funded by the U.S. Department of Energy (DOE)  Vehicle Technologies Office to support the development of accurate computer simulation tools for use in the design, calibration, and control of next generation engine/emissions control systems that maximize efficiency while complying with emissions regulations.  The need for such simulation tools was identified as a key barrier to commercialization of advanced high-efficiency engine systems by the DOE Advanced Engine Crosscut Team.

The DOE Advanced Engine Crosscut Team (known as the Crosscut Team) is composed of representatives from automotive manufacturers, heavy duty engine manufacturers, and U.S. government agencies.  The primary function of the Crosscut Team is to coordinate development efforts for advanced, low-emission, high-efficiency combustion engine systems. This role includes identification and prioritization of specific R&D projects appropriate for government funding.

The mission of CLEERS is to accelerate the development of tools for accurate and computationally efficient simulations of realistic full-system performance of advanced combustion engines and associated emissions control systems through the pursuit of four key objectives:

1. Supporting collaborations among industry, university and DOE national laboratory partners;
2. Developing and disseminating pre-competitive data, parameters, and models;
3. Gathering feedback from industry on critical emissions control research needs; and
4. Coordinating DOE national laboratory research efforts.