Emission Reduction in Hydromethane Combustion
In order to improve the emission characteristics of Compressed Natural Gas (CNG) engines hydrogen can be added to the fuel. Commonly these mixtures of up to 30 Vol% of hydrogen to 70 Vol% of methane are known as hydromethane. With the use of hydromethane the combustion characteristics for internal combustion engines change significantly towards lower NOx as the hydrogen content (lean burn) allows fast generation of H2O which acts as a temperature quencher in the hot methane flame. In addition, the formation of particulate matter is reduced as can be seen in the decrease of precursor molecules like acenaphtene, a cyclic hydrocarbon. For a detailed comparison of the emission profiles of CNG and Hydromethane in transient driving cycles powerful measuring instrumentation is needed that can determine inorganic species like NO and NO2 and likewise organic compounds.
The patented IMR-Technology inside the V&F AirSense can determine all components of interest. By means of just one measurement setup time profiles of the organic and inorganic emissions can be created. Moreover, the IMR-Technology allows for detailed analysis of a range of hydrocarbons, e.g. acetylene, benzene or toluene as well as acenaphtene (C12H10). The latter compound is highly important for studying particle formation in CNG engines. A variety of interface options such as AK protocol ensure easy implementation into the test bench environment.
Figure: Comparison of Gaseous Emissions from a Breda Menarini Methane Powered City Bus
Due to its inherent difficulties in differentiating hydrocarbons > C3 measurement systems based on FTIR technology are not suited for a detailed study of organic emissions from CNG engines. The V&F AirSense mass spectrometer offers great flexibility when it comes to the component selection. Setups can quickly be edited by the operator and new molecules of interest be added. The robust and compact design of the AirSense combined with low maintenance effort makes it an excellent tool for advanced applications in the field of exhaust gas measurements.
- Tailpipe measurements on CNG engines
- Detailed study of organic emissions
- AK protocol for remote operation