Short-circuit effects on spark ignition engine after-treatment and fuel-to-air ratio control
[EN] The short circuit of fresh air is a more and more extended strategy to deal with low-end torque issues, very common in small turbocharged and spark-ignited four-stroke engines. Therefore, from the author¿s point of view, it is interesting to check whether the after-treatment system can work pro...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | inglés |
| OAI Identifier: | oai:riunet.upv.es:10251/123508 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/123508 |
| Access Level: | acceso abierto |
| Palabra clave: | Short-circuit SI engine Fuel-to-air ratio control Three-way catalyst Emissions control MAQUINAS Y MOTORES TERMICOS |
| Sumario: | [EN] The short circuit of fresh air is a more and more extended strategy to deal with low-end torque issues, very common in small turbocharged and spark-ignited four-stroke engines. Therefore, from the author¿s point of view, it is interesting to check whether the after-treatment system can work properly under these conditions. In the present study, the effect of the fresh air short-circuit on engine emissions has been assessed through its impact on the wideband l sensor and the three-way catalyst behaviour, which are the key elements of the fuel-to-air ratio control strategy. In particular, the analysis of the sensor dynamic response shows that the l sensor overestimates the fuel-to-air ratio under short-circuit conditions. The sensor overestimation leads the actual fuel-to-air ratio out of the proper three-way catalyst window; in this sense, results show a non-negligible emissions increase, especially in terms of NOx. Regarding the impact on the threeway catalyst behaviour, the study shows how short-circuit pulses change the exhaust gas composition for a given fuel-toair ratio at catalyst inlet, which also contributes to a penalty in the three-way catalyst efficiency |
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