A Highly Efficient Alcohol Vapor Aspirating Spark–Ignition Engine with Heat Recovery

The fuel properties of the lower alcohols indicate that both, straight methanol and ethanol are fundamentally unsuitable for utilization in the compression ignition process. In order to achieve the optimum possible benefit from the specific advantages of these alcohols, the alcohol-gas engine concept has been developed by Daimler-Benz. Due to partial recovery of the engine’s waste heat by fuel vaporization and extreme lean burn capability, remarkable engine efficiencies are obtained. Design, performance, further development and installation of this system in prototype city buses are described.