Kennedy L.,Millbrook Proving Grounds Ltd. |
Edwards J.,Millbrook Proving Grounds Ltd. |
Stones P.,Millbrook Proving Grounds Ltd.
CONCAWE Reports | Year: 2012
A six vehicle study was carried out to investigate the impact of changes in the volatility characteristics of unleaded gasoline containing 10% vol/vol (v/v) ethanol on regulated exhaust and evaporative emissions and on hot and cold weather vehicle drivability performance. The vehicles selected were representative of the current EU fleet, met or exceeded Euro 4 emissions certification, spanned the range from upper medium to small vehicle classes, were compatible with 10% v/v ethanol according to the manufacturer's warranty information, and included modern gasoline Direct Injection Spark Ignition engine types. For most vehicle tests, results on the baseline gasoline were compared to those on a Step 2 gasoline in which the E70 max and E100 max specifications were relaxed by 10% v/v and 4% v/v, respectively. Some tests were also conducted on Step 1 gasolines in which the E70 max and E100 max specifications were relaxed by 4% v/v and 2% v/v, respectively. The Step 1 gasolines were consistent with CONCAWE's proposal for relaxed volatility specifications while tests on the Step 2 gasolines represented a more severe test for vehicle emissions and drivability performance. All vehicles completed the required driving cycles on all of the test fuels with no false starts, no misfires, no stalls, no failures, and no faults recorded by the On-Board Diagnostics systems. Overall, the impacts of gasoline volatility on emissions and drivability performance were small compared to vehicle-to-vehicle differences.