Real Exhaust Gaseous Emissions and Energy Consumption from the Passenger Car Fleet

The emissions (CVS)) and energy consumption of a representative sample of 28 gas-driven passenger cars are measured on different driving cycles: at 7 constant speeds from 0 to 120 kph, ECE 15, two cycles adapted to the tunnel traffic and 10 statistically representative new cycles including real speed profiles as well as random gear ratios adapted to each vehicle according to its engine speed and acceleration. Some of the 28 driving cycles were driven before and after tuning, with cold and hot start.

The main influence of the average cycle speed and of the speed profiles of the cycles, are shown: constant speeds and ECE 15 results are lower by 15 to 50 %. The great influence of transient speeds is also shown. CO, HC, NOx emissions and energy consumption are respectively 140, 200, 8 and 50 % higher with cold start than with hot stard. The tuning decreases CO and HC emissions by 25 and 14 %, the energy consumption by 5 % but has no influence on NOx emission the age of vehicle has no influence on results, inspite of the more severe emission standards.