A path towards high efficiency using Argon in an HCCI engine 2019-01-0951
High efficiency and low pollutants internal combustion engines are of main importance now more than ever especially due to the increasingly stringent emissions requirements. Low Temperature Combustion, and precisely Homogeneous Charge Compression Ignition (HCCI), in internal combustion engines is certainly the best candidate to achieve these goals. Indeed, combustion of lean mixtures at higher compression ratios than those of conventional internal combustion engines can improve thermodynamic efficiency while achieving low nitric oxides and soot emissions.
The present study proposes to increase more the efficiency out from an HCCI engine by increasing the thermodynamic efficiency. The thermodynamic efficiency is directly proportional to two parameters: the specific heat and the compression ratio. An increase in either of them will lead to higher thermodynamic efficiency. The present study will focus on using a high specific heat ratio working fluid in an HCCI engine. Among the various candidates, argon - a neutral gas with a specific ratio of 1.67 – has been retained for increasing the specific ratio of the working fluid by replacing nitrogen – a gas with a specific ratio of 1.4 - in the cycle. Experiments will be performed on a standard Waukesha variable compression ratio CFR engine modified to run in HCCI mode and modified to allow investigations with argon. Isooctane has been selected as fuel for this study and results will compared engine outcomes and pollutant emissions with a reference cycle.
Abdulrahman Magdy Mohammed, JEAN-BAPTISTE MASURIER, Ali Elkhazraji, robert Dibble, Bengt Johansson
King Abdullah Univ. of Science & Tech., King Abdullah Univ of Science & Tech