| 1. |
- Owrang, Farshid, 1972, et al.
(författare)
-
Chemical analysis of combustion products from an engine power plant fuelled with natural gas
- 2004
-
Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
-
Konferensbidrag (refereegranskat)abstract
- Combustion products, exhaust emissions and engine exhaust deposits formed on thermocouples, positioned after the heat exchanger of an engine power plant, were analyzed chemically. The engine was a lean burn 18W28SG 50 Hz (Wärtsilä NSD, Trollhättan Sweden) fuelled with natural gas equipped with a catalyst (Süd-Chemie NMHC catalyst). The exhaust emissions were sampled using the off-line bottle-in-bag (BiB) method and were analyzed by gas chromatography/flame ionization (GC/FID). Heavier organic compounds and aldehydes were separately collected using adsorption cartridges. The combustion products measured in the emissions were mainly ethene, propene and formaldehyde indicating normal combustion of the fuel in the engine. Organics contained in the engine exhaust deposits were extracted using three different extraction methods: thermal desorption (TD), liquid extraction (LE) and super critical fluid extraction (SFE). The extracts were analyzed by GC/MS. The chemical composition of the deposits before and after TD and LE was characterized using solid-state 13C NMR. The amount of oxygen in the deposits was measured using cyclic fast neutron activation analysis (cFNAA). A substantial part of the deposits (77 weight %) consisted of extractable organics. The remaining part of the deposits consisted of a carbon structure rich in aromatics and aliphatics. The amount of oxygen in the deposits was about 17 weight %. As expected, the results demonstrated that the deposits originated from engine oil. This was shown clearly using GC/MS analysis of components desorbed or extracted from the deposits combined with NMR of deposits.
|
|
| 2. |
- Owrang, Farshid, 1972, et al.
(författare)
-
Solid-state 1H NMR spin-lattice relaxation in combustion chamber deposits from a gasoline direct injection engine
- 2004
-
Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
-
Konferensbidrag (refereegranskat)abstract
- 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.
|
|
