connection (25 mm diameter) is placed to direct a portion of the
burned gases from the exhaust pipe to back into the intake runner.
This method of burned gas utilization, referred to as external
exhaust gas recirculation (Ex-EGR), will result in a higher intake
charge temperature and a different intake charge composition.
As is illustrated in Fig. 1 , K-type thermocouples (±1 C accuracy)
are positioned at strategic locations, i.e., Tex, Tin and Tsc. The Tex is
measured from 30 mm away from the downstream side of the
exhaust port, and the Tsc is estimated from 10 mm ahead of
the upstream side of the scavenging port. Tin is measured after
the Ex-EGR mixing box. A spark-plug-type piezoelectric pressure
transducer (KISTLER 6117B) is used for a pressure history recording. The engine crankshaft is coupled to a crank angle encoder (KISTLER 2613B) to measure the crank angle degree (CAD) with
resolution of 0.2 . A high-speed data acquisition system
DEWE5000 is connected to the DEWESoft and DEWECa software
for relevant data processing