Investigation of post-oxidation mechanism on emissions and turbo performance in a DISI engine

Kumar, Madan; Moeeni, S; Kuboyama, Tatsuya; Moriyoshi, Yasuo

doi:10.1016/j.energy.2020.119465

Cited by 4 publications

(8 citation statements)

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“…Post-oxidation has emerged as a potential solution to improve turbo performance and three-way catalyst light-off temperature along with emissions reduction. [1][2][3][4][5][6][7][8][9] In the post-oxidation phenomena, the in-cylinder combustion shifted to a slightly rich mode, and as a result, higher concentrations of CO, THC, and H 2 were emitted out to the exhaust manifold. Then, the fresh air which can be either introduced by the variable valve timing (VVT) based scavenging phenomena or by the secondary air injection (SAI) at the exhaust port for the chemical reaction between unburned gas species and O 2 .…”

Section: Introductionmentioning

confidence: 99%

“…Also, the inhomogeneity plays a significant drawback at the higher overlap which restricts the efficient postoxidation. 4,5,9,10 Several kinds of simulative and experimental research have been conducted on the scavenging (VVT tuning) based post-oxidation phenomena. [1][2][3][4][5][6][7]9,11,12 Guenther et al performed a simulative study on the scavenging-based post-oxidation phenomena.…”

Section: Introductionmentioning

confidence: 99%

“…4,5,9,10 Several kinds of simulative and experimental research have been conducted on the scavenging (VVT tuning) based post-oxidation phenomena. [1][2][3][4][5][6][7]9,11,12 Guenther et al performed a simulative study on the scavenging-based post-oxidation phenomena. The reaction kinetics mechanism including CO and H 2 was investigated and found that the H 2 shows the key element for the fast reaction.…”

Section: Introductionmentioning

confidence: 99%

“…In both cases, it was found that the emissions and turbo-performance become better at late ignition and early injection timing due to oxidation reaction. 5 At higher overlap, the in-homogeneity has appeared which restricts the post-oxidation phenomena that were analyzed and improved with a bypass adapter design implementation in simulation and experimental validation. 9 Koehlen et al investigated the post-oxidation phenomena and found that not only the quality of the mixture formation and combustion but the distribution of flow, temperature, and concentration of air and exhaust gas are important for the optimum post-oxidation.…”

Section: Introductionmentioning

confidence: 99%

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Post-oxidation phenomena enhancement with scavenging and secondary air injection in exhaust manifold of a turbocharged GDI engine

Kumar

Moriyoshi

Kuboyama

2022

International Journal of Engine Research

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A detailed investigation of post-oxidation phenomena by individual and combined effects of scavenging (VVT tuning) and secondary air injection (SAI) was performed. The 1-D simulation including a post-oxidation model developed by Stuttgart University as an international collaboration was used for investigation which includes the main exhaust gas species as CO, H2, and O2-based chemical reactions. Then, experimental validation was conducted on a 4-cylinder turbocharged gasoline direct injection (GDI) engine. From the results, it was noted that the post-oxidation can be actuated at limited operating conditions as higher overlap in moderated speed and load only when scavenging phenomena are considered. However, at lower overlap, it is restricted due to lower O2 scavenging even though the exhaust temperature meets the post-oxidation requirement. Also, the in-homogeneity observed at higher overlap that restricts the significant post-oxidation before the turbocharger upstream. On the other hand, the SAI mechanism can actuate the post-oxidation even at lower overlap if enough O2 concentration, exhaust temperature, and adequate mixing are attained. Hence, the post-oxidation zone can be extended to lower speed-load and overlap if both parameters as scavenging and SAI introduced together. This can possibly lead to better turbo-performance along with lower emissions. However, thermal efficiency needs to be compromised to some extent. It was also found that the effective post-oxidation can be actuated by SAI compared to scavenging-based phenomena if the same concentration of the O2 and temperature are maintained by both mechanisms. This appeared due to the fresh air continuously injected at the exhaust port even at the time of exhaust valve opening duration in SAI mechanism that allows the better mixing of O2 and hot unburned gas species. However, in scavenging-based phenomena, firstly, hot unburned gas passed through the exhaust manifold and then scavenged air follows which restricts mixing between scavenged air and unburned gas species.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Post-oxidation phenomena enhancement with scavenging and secondary air injection in exhaust manifold of a turbocharged GDI engine

Kumar

Moriyoshi

Kuboyama

2022

International Journal of Engine Research

Self Cite

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show abstract

“…At the same time, less unburned fuel is brought into the catalyst, which prevents the catalyst from rising in temperature. In past, another methodology for the post-oxidation has been also adopted such as, secondary air injection in exhaust port that can enable secondary reaction (post-oxidation) and could increase enthalpy at turbocharger upstream and hence turbo-lag can be reduced [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%