Changes in Pollutant Emissions from Passenger Cars Under Cold Start Conditions

CO, CO², HC, CH⁴, NOx, N²O emissions as well as emissions of 10 PAHs and fuel consumption were measured on 10 conventional petrol-engined passenger cars, 10 vehicles equipped with 3-way catalysts, and 5 diesel-engined vehicles over a great number of driving cycles under hot or cold start conditions: the 2 standardized European and American cycles, Highway cycle, 4 hot cycles representative of real-world driving conditions, and 3 representative mini-cycles, which have been repeated 15 times after a cold start. Simultaneously, water and oil temperatures were measured to assess engine temperatures. The analysis of the results enabled the monitoring of emission and temperature changes with time for various kinematic types. The limit of hot temperature, the distance travelled under cold start conditions (over about 6 km), the excess emission rates under cold start conditions, and absolute excess emissions after a cold start could be thus determined. These parameters significantly vary according to the vehicle technology, driving cycle and pollutant type. In addition, a great number of results are presented relative to hot emissions and standard cycles.