Journal of Transportation Engineering and Its Applications ISSN: 3107-4499 (Online)

Authors: Nicholas Evans, Dr Don Law 

Abstratc: During the twentieth and twenty-first century many have taken the approach to develop lean combustion in gasoline engines using conventional fuel ling and ignition systems. While lean combustion is achievable, only small amounts of enleanment are achievable meaning that improvements are limited before the lean limits reached and combustion become suns table. In the pursuit of efficiency both conventional and non-conventional operation methods have been explored. Whileλ1.3is achievable using conventional fuel and ignition systems, λ1.4 typically results in unstable combustion troughs lower flame fronts and higher hydrocarbon emissions than stochio metric combustion.

MAHLE have developed MJI (MAHLE Jet Ignition), a pre-combustion chamber with a small pre-chamber volume fit ting in the place of a conventional spark plug. Both pre-chamber and cylinder are supplied with fresh air fuel mix where fuel is delivered in an approximate3:97ratiorespectively. Like other pre-chamber combustion methods combustionis initiated in the pre-chamber as a rich Mixture where a thoroughly mixed lean mixture in the cylinder is ignited by the resulting flame front from the pre-chamber. Using these design stable lean limits have been dramatically improve do more conventional fuelling and ignition systemstoλ2.1. Faster CA10-90has also been achieved than conventional methods with significant high load knock limits improvements. The normal fficiency in the engine tested increasedby25%resultingin a peak brake thermal efficiency (BTE) greater than 41%andfuelconsumptions of sub 200g/k Wh. additionally; nitrogen oxide (NOx) emissions have been significantly reduced.