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The work reports results from tests employing different cooled EGR routes on a ‘Sabre’ direct-injection spark-ignition (DISI) research engine. As standard, this engine has been configured to provide good fuel consumption from a combination of mild downsizing, a combustion system with close-spaced injection and the adoption of a three-cylinder configuration in concert with an exhaust manifold integrated into the cylinder head. This has already been shown to offer a rated power specific fuel consumption of 272 g/kWh without cooled EGR. Three different EGR configurations are tested, with the best BSFC at nominal rated conditions being found to be 257-258 g/kWh at a cooled EGR rate of 6%. All of the EGR routing configurations tested in this work permit ready operation of the engine at Lambda 1 and MBT conditions, however, the results show little sensitivity in the combustion system to the actual routing employed.

The use of methanol as spark-ignition engine fuel can help to increase energy security and offers the prospect of carbon neutral transport. Methanol's properties enable considerable improvements in engine performance, efficiency and CO2 emissions compared to gasoline operation. SAE paper 2012-01-1283 showed that both flex-fuel and dedicated methanol engines can benefit from an operating strategy employing exhaust gas recirculation (EGR) to control the load while leaving the throttle wide open (WOT). Compared to throttled stoichiometric operation, this reduces pumping work, cooling losses, dissociation and engine-out NOx. The current paper presents follow-up work to determine to what extent these advantages still stand over an entire drive cycle. The average vehicle efficiency, overall CO2 and NOx emissions from a flexible fuel vehicle completing a drive cycle on gasoline and methanol were evaluated.