Enhanced Engine Improvements

Enhanced Engine Improvements

OPEN 2015
Ann Arbor, Michigan
Project Term:
07/14/2016 - 12/31/2019

Critical Need:

In recent decades, the fuel economy of lightweight passenger vehicles has increased significantly due to improvements in vehicle design, engines, and transmissions. However, further increases in fuel efficiency through additional engine downsizing will have adverse effects on drivability and market acceptance. Automakers need innovative approaches to avoid the severe tradeoff between vehicle fuel efficiency and drivability without incurring the high cost of full hybridization. Presently there are tremendous opportunities that can be achieved by combining low-voltage electric control and advanced combustion. Current gaps in technology include model-predictive control that satisfies drivability constraints while operating the engine at its highest efficiency using minimal electric torque-assist or boost-assist during transients. Predicting and prioritizing the benefits of using electric energy for assisting the engine by accelerating its breathing (faster air-path response and controlled combustion), under high transient load will help the automakers achieve even lower fuel consumption and emissions.

Project Innovation + Advantages:

The University of Michigan team will develop a compact micro-hybrid configuration that pairs an Electrically Assisted Variable Speed (EAVS) supercharger with an exhaust expander Waste Energy Recovery (WER) system. Together, the EAVS and WER can nearly eliminate the slow air-path dynamics associated with turbocharge inertia and high exhaust gas recirculation (EGR). The EAVS system compresses engine intake air to increase engine power and allows the engine to have valuable “breathing time.” This breathing time allows for a coordinated intake boosting and exhaust vacuum, so that the combustion timing and fueling is always optimal. Meanwhile, the WER system will capture exhaust energy, store it in a low-voltage battery together with energy from regenerative braking and later reuse it to assist the engine under transient acceleration loads, helping to further increase fuel efficiency. The team’s innovation could increase fuel economy in advanced vehicles by 20%.

Potential Impact:

If successful, the University of Michigan project team will improve fuel economy in vehicles by 20% at a much lower cost than alternative engine technologies.


This technology seeks to decrease fuel consumption and will help decrease demand for foreign sources of fossil fuel. 


If successful, this technology will improve vehicle fuel efficiency and reduce CO2 emissions while ensuring customer acceptability.


This technology could allow consumers to save on their transportation fuel costs.


ARPA-E Program Director:
Dr. Christopher Atkinson
Project Contact:
Prof. Anna Stefanopoulou
Press and General Inquiries Email:
Project Contact Email:

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