Delayed charging. A means to improve two-stroke engine characteristics
- Universite Paris (France)
We have developed and patented a new simple device which reduces the amount of short-circuited fresh charge in two-stroke cycle engines and produces stratified charging and combustion. The principle consists in scavenging the burnt gases with fresh air and delaying the introduction of the fresh charge in the cylinder. A numerical simulation showed a good promise of consumption and pollution improvement for this configuration. Then, preliminary bench tests have been carried out with a 50 cc production engine and the same modified engine including a delay-circuit. Due to delayed charging, brake specific fuel consumption shows a mean 20% reduction, down to a maximum of 25% comparing to production engine figures; unburnt hydrocarbons show a mean 35% reduction, down to more than 50%; carbon-monoxide production decreases to a mean 1% concentration; and torque increases at low r.p.m., but lowers at higher speeds of revolution due to the diminished permeability of this first prototype engine. 23 refs., 10 figs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 91281
- Report Number(s):
- CONF-9409289-; TRN: 95:005935-001
- Journal Information:
- SAE Special Publication, Journal Issue: 1049; Conference: 1994 Society of Automotive Engineers (SAE) off highway and powerplant congress and exposition, Milwaukee, WI (United States), 12 Sep 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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