The Potential of Synthetic Fuels to Meet Future Emission Regulations

Authors

Dr.-Ing. H.-O. Herrmann, Dr.-Ing. S. Keppeler, Dipl.-Ing. W. Frieß, DaimlerChrysler AG, Stuttgart; Dr. J. J. Botha, Sasol Technology (Pty) Ltd., Rosebank, RSA; MSc.Eng. P. Schaberg, Sasol Advanced Fuel Laboratory, University of Cape Town, RSA; MSc.Eng. M. Schnell, SasolChevron Consulting Ltd., London

Year

2006

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 622

Summary

The potential of GTL diesel fuel for further improving engine performance and reducing exhaust emissions beyond Euro 4 was investigated in a Mercedes-Benz E320 CDI passenger car. Starting with the outlook on the production and properties of GTL fuel against the anticipated future diesel demand, the paper addresses the impacts of GTL diesel fuel on heavy-duty and light-duty engines. Based on preceding work on un-adapted engines, published in an earlier paper in 2004 at the 25th International Vienna Motor Symposium, the hardware configuration and software calibration of the E320 engine were now modified to better utilize the advantageous properties of the Sasol Chevron GTL diesel fuel. In order to keep engine changes at a minimum, hardware modifications were limited to lowering the compression ratio and optimizing the injection equipment. These hardware modifications required the adaptation of the engine software calibration, such as injection system parameters, boost pressure adjustment, and EGR rates. It has been shown that, by detailed bench work and chassis dynamometer testing, the vehicle, which is equipped with a DPF and has a Euro 4 calibration in its original form, can comply with the very stringent nitrogen oxides emission limits of 0.08 g/km (NEDC) when moderately modified and operated on GTL diesel fuel. This was achieved without any active nitrogen oxides exhaust gas aftertreatment. This establishes a very promising outlook for a cost-efficient means for reducing exhaust emissions, and again highlights the benefits that may be obtained with cleaner fuels (GTL diesel fuel is free of sulfur and aromatics and has a cetane number > 70). The paper presents details of the fuel, the engine modifications and the test results obtained so far.

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