Future Trends in Spark Ignition Engines 2001-24-0085
The spark ignition engines offer a remarkable potential of improvement – from performances to consumption and pollution – which begins to be better exploited than in the past. This survival process is imposed by the increasing demand for performances, by the drastical limitation of pollutant emission, as well as by noticeable competitors such as the fuel cell. The improvement base for SI engines consists in the accurate control and adaptation of the thermodynamic process stages – scavenging, mixture formation and combustion – for every load, speed and surrounding conditions.
The classical process itself offers a substantial improvement reserve when applying a load and speed adapted process management. The higher level of improvement is given by internal mixture formation using direct injection, by fully variable valve control as well as by generally higher load operation using super- or turbocharging. All these elements can be combined in an advantageous down sizing concept. The next improvement level is allowed when tuning SI engines for restricted operation windows – in hybrid propulsion scenarios. The future of SI engines is furthermore ensured by their adaptability for alternative fuels such as CNG or LPG and much more for renewable energetic sources – ethanol, methanol and their blends.