Electrification and E-Fuels – The Future of Otto- and Diesel-Engines

Authors

Dr.-Ing. M. Härtl, C. Kraus MSc, Prof. M. Jaensch PhD, Technical University Munich:

Year

2022

Print Info

Production/Publication ÖVK

Summary

The German policy of energy transition aims for climate neutrality before the year 2045 and poses a great challenge to the transport sector, as nearly 95 % of the energy consumed there is based on fossil ressources today. The reason: fuels produced from oil and natural gas offer high energy density, easy handling, and low cost, while technically and economically attractive alternatives have been scarce. In the futher progress of the energy transition, electromobility is expected to increase while at the same time a market for E-fuels could possibly start to grow. The transport sector may act as an enabler and driver for such a development as liquid fuels can easily replace conventional energy carriers in the existing fleet. Depending on the different applications, multiple forms of energy storage will be used as long as they exhibit green-house-gas savings over their life cycle from cradle to grave. Hydrogen as the most simple and carbon-free molecule and methane with its world-wide infrastructure are promising E-fuels. Methanol as well as various other oxygenates and hydrocarbons are liquid options when it comes to chemical energy storage. Many of these options can be seen as „functional“ E-fuels, in a sense that their properties are optimized for the use in internal combustion engines. Oxygenates with C₁-structure (no C-C-bonds) for example show soot-less combustion and are available either with high ignitability (CI engine use) or extreme knock-resistance (SI engine use). Engines can achieve high thermodynamic efficiency while critical pollutant emissions such as particles and nitrogen oxides are avoided effectively. The additional use of a capable exhaust gas after-treatment has been shown to even allow the design of emission neutral combustion engines.

This conference paper presents a systematic overview of several important E-fuels and compares them to one another. In a second part the SI fuels dimethyl carbonate and methyl formate are presented as an application example, and recent experimental results from a research engine at the Technical University of Munich are discussed.

ISBN

1920-2323-23-1

Number of pages

20 Order