Is there a way to increase the efficiency of a 2 stroke engine, and in turn obtain a greater power from the engine, can we introduce a new scavenging mechanism, in order to decrease the fuel used to get the exhaust fuel out of the engine and thus increases the fuel efficiency and thus the power.
Increasing efficiency of two-stroke engines is closley related to the improvement of trapping efficiency of the scavening process. This can be achieved by:
- inprovement of scavening timing and and scavenging flow optimization (as a function of the scavange ports design)
- improvement of exhaust timing (e.g. by variable exhaust scavenge port) and exhaust pressure characteristics, supporting the scavenge process
- separation of scavenge process and mixture preparation by application of specific fuel injection system for two stroke engines
I have added some publications, which might be of interest for you. If required, I can send you the full-text versions.
Kind regards,
Mario
Conference Paper Potential of high technology 50cm³ two stroke and four stroke engines
Conference Paper Exhaust gas emissions of small capacity 2 & 4 stroke engines
Conference Paper The New Generation Air Cooled 50cc 2-Stroke Engine from TOMOS
If the engine you are talking about is a SI engine why not think of injecting the fuel just after covering exhaust ports while piston is moving up in the compression stroke. Of course if it is a CI engine you may not lose fuel in the exhaust as the scavenging process will be done by sir only.
As per Professor. Kamal Nasreldin Abdalla, if it is SI engine and the fuel is injected after the Exhaust Value Close(EVC) (i.e during compression stroke) it is SIDI gasoline engine. It is widely reported that SIDI gasoline engines produce higher particle number emissions than diesel engines, especially at cold start, acceleration and high load conditions [1][2]. Yes, if we are injecting after EVC, the amount of fuel lost through scavenging is nil, so the efficiency will increase for sure, but emissions are also equally important with the efficiency. Along with that the chances of soot emissions are also high, for which we may have to use EGR or water injection technology, which could reduce our efficiency. One best thing about it is, since it is direct injection, the intake is just air so we can boost them using turbocharger or supercharger, which will increase the volumetric efficiency (Not the thermal efficiency) and the power.
If I was there in your situation, I would stick to the homogeneous mixture concept and try to enhance the scavenging process by optimizing (obviously with a computational software)
A single two-stroke engine produces pollution equivalent to that of 30 to 50 four-stroke automobiles[3]. The main reason for this is the fuel air mixture are getting mixed with the oil in the crank case. The above problem can be rectified by using intake and exhaust valve, but again it will reduce your mechanical efficiency and so does your brake thermal efficiency.
References:
Article Experimental investigation and comparison of nanoparticle em...
Conference Paper Particulate Matter Emission Comparison of Spark Ignition Dir...
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