Developing a numerical method for simulating physical and chemical processes that lead to LSPI
- Delivery
- Available on this site
- Format
- Price
- Non-members (tax incl.)：￥1,100 Members (tax incl.)：￥880
- Publication code
- 20239261
- Paper/Info type
- Other International Conferences
- Pages
- 1-13(Total 13 p)
- Date of publication
- Aug 2023
- Publisher
- JSAE & SAE
- Language
- English
- Event
- 2023 P, E&L
Detailed Information
| Category(E) | IC4 Modeling, MBD, Engine Systems and Control |
|---|---|
| Author(E) | 1) Adnan Mahmood, 2) Paul Hellier |
| Affiliation(E) | 1) BP, 2) University College London |
| Abstract(E) | To improve thermal efficiency, engines are being significantly downsized. A common issue in gasoline engines which limits thermal efficiency and is further exacerbated by downsizing, is low speed pre-ignition (LSPI). A Multiphysics approach is used, initially using a validated 1D engine performance model of a GTDI engine, to provide boundary conditions. A strong emphasis on validating each simulation methodology is maintained at each stage. A hydrodynamic model of the ring-liner and Lagrangian CFD problem are used to investigate the impact of engine oil fluid properties on the mass of oil transported from the crevice volume to the combustion chamber. A heat transfer and evaporation model of a single droplet inside an engine environment was developed for alkanes of chain lengths representing the extremes of the chain lengths present in engine oil. The droplet evaporates at a crank angle which is close to where LSPI is observed. The hydrocarbon study ends with a CFD bomb simulation to understand why engine oil like hydrocarbons ignite in rig tests but not in an engine. This paper then develops a single particle detergent model in an engine environment, to initially understand why ignition occurs when a calcium Ca based detergent is present but not in the case of a magnesium Mg detergent. It was found from simulation that the common theory of calcium oxide CaO resulting from thermal degradation from the previous cycle then reacting with Carbon dioxide (CO2) late in the compression stroke is unlikely. There is a stronger case for the CaO particle causing ignition as it is present in fresh engine oil sprayed onto the liner. As predicted by the hydrocarbon evaporation model the oil will cover and protect the CaO particle until late in the compression stroke when the oil will evaporate, exposing the CaO particle to CO2 |
