Solid-state 1H NMR spin-lattice relaxation in combustion chamber deposits from a gasoline direct injection engine
Paper in proceeding, 2004

Combustion chamber deposits from a gasoline direct injection stratified charge SI engine were analyzed using solid-state1H inverse recovery NMR spectroscopy, before and after thermal desorption (TD). The engine was run with a typical European base fuel, containing 9.8% MTBE. Before TD, solid-state1H NMR showed two broad peaks representing aliphatics and aromatics. The results showed that T1 (the relaxation time) of the aliphatics was significantly longer than T1 of the aromatics in the deposits. Deposits taken from the piston bowl, with the lowest volatility content, showed the shortest T1. In comparison, piston squish and piston bowl deposits, with higher volatility content showed a longer T 1. After TD, T1 of the aliphatics was shorter than the corresponding T1 of the aromatics. A decreasing T1 of aliphatics may be used for following a transition from a liquid (engine oil), via a semi-solid deposit to a solid carbon backbone. This may give a rough measure of the engine oil content of the deposits. Copyright © 2004 SAE International.

Author

Farshid Owrang

Chalmers, Department of Materials and Surface Chemistry

Jim O. Olsson

Department of Physical Chemistry

Jörgen Pedersen

Department of Physical Chemistry

SAE Technical Papers

01487191 (ISSN) 26883627 (eISSN)


978-076801319-1 (ISBN)

2004 SAE World Congress
Detroit, USA,

Subject Categories

Inorganic Chemistry

Tribology

Other Chemical Engineering

DOI

10.4271/2004-01-0042

More information

Latest update

4/22/2020