In times of escalating oil prices and increasing demand, associated with intense ecological awareness, the automobile industry is obliged, either by government authorities or by public opinion, to develop technical solutions to promote fuel conservation and alternative fuels usage.
Therefore, in the next decades, before the total replacement of fossil fuels, the development of Otto cycle engines will focus on measures to reduce the fuel consumption and to increase the use of bio-fuels. Recent progress of on-board electronics have led to the development of sophisticated engine management systems to control the air charge, fuel injection and spark-ignition processes at an individual cylinder level, in order to optimize fuel economy and pollutant emissions.
This article shows measurement data of fuel consumption, engine performance and CO2 emissions obtained, by optimizing the inlet valve timing, during the engine test bench application of a Bosch Flex-Fuel system on a 1.8 l engine equipped with variable inlet valve camshaft (VVT). Additional measurements of HC, CO and NOx emissions performed at the vehicle emissions laboratory are also reported, even though they are not the main focus of this paper.
The test results allow the establishment of a correlation between the green house gases (GHG) emissions from gasoline and ethanol fuelled vehicles and its implications on the green house effect on a well-to-wheel basis.