Abstract
The development and validation of detailed simulation models of in-cylinder combustion, emission formation mechanisms and reaction kinetics in the exhaust system are of crucial importance for the design of future low-emission powertrain concepts. To investigate emission formation mechanisms on one side and to create a solid basis for the validation of simulation methodologies (e.g. 3D-CFD, multi-dimensional in-cylinder models, etc.) on the other side, specific detailed measurements in the exhaust system are required. In particular, the hydrocarbon (HC) emissions are difficult to be investigated in simulation and experimentally, due to their complex composition and their post-oxidation in the exhaust system. In this work, different emission measurement devices were used to track the emission level and composition at different distances from the cylinder along the exhaust manifold, from the exhaust valve onwards. A fast-FID (FFID) was used to measure the cycle-resolved total-HC (THC) emissions and an ion molecule reaction mass-spectrometer (IMR-MS) to determine the average concentration of some selected HC components. Conventional exhaust analyzers were used additionally to measure the average levels of the important exhaust gas components (THC, NOx, CO, CO2, O2). The measurements were conducted on a 0.4 l single-cylinder spark-ignited (SI) research engine. The effects and cross-effects on emissions of several relevant operating parameters were evaluated. Different result patterns are observed in the different measuring positions. In this work, selected results on the effect of air-to-fuel ratio and spark timing are presented. For the air-fuel-ratio variation, the FFID results show that the THC quenching increases with lean operating condition and the IMR-MS that this increase corresponds to an increase in fuel-HC and a reduction in non-fuel-HC. In the spark timing variation, the trends of THC in the exhaust port and in the exhaust runner suggest the presence of HC oxidation in the exhaust port, due to higher exhaust temperature with retarded combustion. Additionally, the IMR-MS confirm the presence of late and incomplete oxidation with the increase of non-fuel species.
| Original language | English |
|---|---|
| Journal | SAE Technical Papers |
| Volume | 2019-April |
| Issue number | April |
| DOIs | |
| Publication status | Published - 2 Apr 2019 |
| Event | SAE World Congress Experience, WCX 2019 - Detroit, USA United States Duration: 9 Apr 2019 → 11 Apr 2019 |
Bibliographical note
Funding Information:This work was founded by the DFG (Deutsche Forschungs-gemeinschaft, german research foundation), within the framework of the research training group “mobilEM” (grant number GRK 1856). The authors wish to thank the DFG also for enabling this work by funding the IMR-MS used in these measurements. Additional thank goes to the Institute of Combustion Technology (ITV) of the RWTH Aachen University for the lending of the FFID and to Cambustion Ltd. as well as MS4-Analysentechnik GmbH for the technical support on the FFID and the IMR-MS. Lastly, the authors wish to thank Prof. Wai K. Cheng for the support on the post-processing of the FFID measurements.
Publisher Copyright:
© 2019 SAE International. All Rights Reserved.
Funding
This work was founded by the DFG (Deutsche Forschungs-gemeinschaft, german research foundation), within the framework of the research training group “mobilEM” (grant number GRK 1856). The authors wish to thank the DFG also for enabling this work by funding the IMR-MS used in these measurements. Additional thank goes to the Institute of Combustion Technology (ITV) of the RWTH Aachen University for the lending of the FFID and to Cambustion Ltd. as well as MS4-Analysentechnik GmbH for the technical support on the FFID and the IMR-MS. Lastly, the authors wish to thank Prof. Wai K. Cheng for the support on the post-processing of the FFID measurements.
ASJC Scopus subject areas
- Automotive Engineering
- Pollution