JOINT MAE-CER SEMINAR
Real-World Mass Emission Determination of a High Efficient Mono-Fuel CNG Light Duty Vehicle
Global challenges such as increasing energy efficiency, reducing greenhouse gas emissions as well as improving air quality lead to ambitious goals and mandatory EU targets for new emissions standards. The European Parliament has approved proposals to limit average CO2 emissions from new cars to 120 g/km. Gaseous energy sources, like natural gas and biogas should become an essential fundament as fuel, which offer lower CO2 and pollutant emission even because of their chemical composition and higher energy density.
A high efficiency monofuel CNG light duty vehicle based on the Opel Zafira was investigated under real world conditions and the results are presented in this study. To analyze the real world performance of the monofuel CNG vehicle due to fuel consumption and exhaust emissions representative road-test routes were conducted, including sections with significantly different driving conditions. Furthermore, driving tests at different constant speeds on freeway as well as full-load tests were carried out. The influence of overall powertrain optimization, systematic reduction of the driving resistance and light weight storage system will be addressed.
The test vehicle was equipped with a new ultra compact On-Board measurement system. As experimental equipment, the on-board system measures in-car the exhaust mass emissions in real time. Every second, a full dataset of emission rates is provided. The fuel consumption is calculated with the carbon balance method according to the EU Commission directive 1999/100/EC. The gained measurement results from the real world tests are based on thousands of single measurement sets, which were averagely weighted. Additionally, a GPS tracking was implemented to link the received geographical information of the road-test routes with the measured exhaust emission data.
A detailed validation of the PEM integrated real-time modal mass emission measurement by comparing different intake air mass flow determination principles will be presented. Furthermore the measurement results were validated with Matlab Simulink models of the powertrain and vehicle.
Finally the benchmarking of the CNG car real-world results with a regular Diesel car of the same make and type will be addressed. The results of the investigations showed that the CNG LDV CO2 emissions are significantly lower than the EU limits.