Browse Publications Technical Papers 2016-01-0683

Improving the Efficiency of Conventional Spark-Ignition Engines Using Octane-on-Demand Combustion - Part II: Vehicle Studies and Life Cycle Assessment 2016-01-0683

This paper is the second of a two part study which investigates the use of advanced combustion modes as a means of improving the efficiency and environmental impact of conventional light-duty vehicles. This second study focuses on drive cycle simulations and Life Cycle Assessment (LCA) for vehicles equipped with Octane-on-Demand combustion. Methanol is utilized as the high octane fuel, while three alternative petroleum-derived fuels with Research octane numbers (RONs) ranging from 61 to 90 are examined as candidates for the lower octane fuel.
The experimental engine calibration maps developed in the previous study are first provided as inputs to a drive cycle simulation tool. This is used to quantify the total fuel consumption, octane requirement and tank-to-wheel CO2 emissions for a light-duty vehicle equipped with two alternative powertrain configurations. The properties of the lower octane fuel are shown to affect the vehicle fuel consumption and CO2 emissions significantly. In particular, the lower octane fuel indirectly defines the evolution of several key fuel properties with engine load. This synergistic relationship ultimately presents a trade-off between minimizing the vehicle fuel consumption and CO2 emissions.
Finally, the well-to-tank CO2 emissions arising from the production and distribution of each fuel were estimated for several common feedstocks and production routes. This data was combined with the tank-to-wheel CO2 emissions to estimate the overall carbon intensity of each dual-fuel combination using a Life Cycle Assessment. This enables the broader benefits and practical challenges to be analyzed from the perspective of a range of stakeholders. Overall, this work suggests that Octane-on-Demand can provide considerable fuel economy and well-to-wheel CO2 emissions benefits in comparison with conventional light-duty vehicles operated on standard gasolines.


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