8. Heavy Duty Diesel Engines Operating on 100% Methanol for Lower Cost and Cleaner Emissions

There is great interest in incorporating methanol fuel across a variety of energy and transportation sectors for many reasons, including increased regional availability, potential to use renewable fuel production pathways, and lower fuel costs compared to petroleum-derived fuels. This chapter describes a method of integrating methanol into a traditional diesel engine architecture, allowing the engine to operate on 100% methanol fuel while maintaining high torque and efficiency. By using increased engine insulation, a high-temperature environment is created which enables any fuel, regardless of cetane number, to auto-ignite with short ignition delay time upon direct injection. This “fuel agnostic” mixing-controlled compression ignition engine can be operated on fuels such as methanol or ethanol, without ignition improver additives. Further benefits arise from marrying a low-carbon fuel like methanol to this high-efficiency architecture—namely that the engine can be operated at a stoichiometric air/fuel ratio, without exceeding soot emission regulation limits nor requiring a particulate filter to do so. Finally, the stoichiometric ratio allows for three-way catalysis after treatment, an order of magnitude lower in cost and more effective than selective catalytic reduction, providing a credible pathway to meeting near-zero NOx standards such as the 0.02 g/hph target. In this way, emissions of soot, NOx, and net CO₂ (if renewable pathways are used to produce methanol) can all be lowered, enabling cleaner air quality and a ready transition to a low-carbon global economy.