Benefits of Octane-On-Demand in an E10-Gasoline Engine Vehicle Using an On-Board Fuel Separator
2022-01-0506
03/29/2022
- Event
- Content
- Knock in gasoline engines at higher loads is a significant constraint on torque and efficiency. The anti-knock property of a fuel is closely related to its research octane number (RON). Ethanol has superior RON compared to gasoline and thus has been commonly used to blend with gasoline in commercial fuels. As a result, an onboard Octane-on-demand (OOD) concept that separates commercial gasoline with ethanol content into high-octane fuel with high ethanol fraction and a lower octane remainder has been developed. It then uses both fuels in varying proportion to provide to the engine a fuel blend with just enough RON to meet the ever changing octane requirement that depends on driving pattern. In this work, the authors assessed the OOD concept on a state-of-art high-efficiency SI engine in three tasks: (1) Comparison of performance characteristics of an up-to-date reference engine coupled with cylinder deactivation (CDA) system, with a similar OOD engine. (2) Study of the performance of OOD engine at engine-in-vehicle level. This involves interaction between the time-dependent onboard fuel separation process and fuel consumption under different driving cycles, such as FTP75 and US06. (3) Potential of the OOD concept for engine downsizing with the needed boosting to maintain maximum torque. It was found that overall mid-to-high load engine efficiency is improved significantly with the OOD engine. However, the improvement in the CDA operating region is small as it is countered by the higher combined pumping and friction losses. At the engine-in-vehicle level, the performance of OOD engine is dependent on the control strategy. With appropriate spark control strategy, the efficiency improvement with OOD engine is between 1% to 1.5%, depending on the aggressiveness of the driving pattern. The OOD concept is an attractive approach to increase efficiency of downsized engine. However, this requires the ethanol content in the pump fuel be significantly higher than currently typical 10% levels.
- Citation
- Chen, Y., Kasseris, E., Heywood, J., Han, D. et al., "Benefits of Octane-On-Demand in an E10-Gasoline Engine Vehicle Using an On-Board Fuel Separator," SAE Technical Paper 2022-01-0506, 2022, .