Exhaust Purification Performance Enhancement by Early Activation of Three Way Catalysts for Gasoline Engines Used in Hybrid Electric Vehicles

Modeling on a Three-Way Catalyst Used in Series Hybrid Electric Vehicles Considering Its Specific Engine Operation Attribute

“…Kinetic Parameter Fitting for the Model Gas Experimental Results. In our previous study, 8 two or three gas species of specific model gas tests were performed, and the kinetic parameters derived from them were used as the initial parameters. Reactions on the OSC site were set as two groups, namely, fast-and slow-OSC, followed by parameter refitting.…”

“…The 1-D TWC model in this study is based on the model constructed in our previous study. 8 Although the real catalyst consists of two layers, namely, a Pd top coat and Rh bottom coat, the catalyst layer is defined as a monolayer to simplify kinetic parameter fitting and reduce calculation costs. Subsequently, the existing model developed by Ramanathan et al 5 was consulted, and the installation of the inhibition term was also followed by the model.…”

“…With respect to fuel economy and emission control of HEVs, Gao et al investigated the use of numerical models of engine and aftertreatment systems and simulations. , In contrast, such literature concerning SHEVs is scarce. In our previous study, we performed a vehicle test on a commercially produced SHEV (the dimensions of the cc-TWC employed were 99.2 mm ( D ) × 90.2 mm ( L ). We focused on the light-off process from cold start in a worldwide light-duty test cycle (WLTC) mode to construct a TWC model that reproduces the catalytic performance, which is limited in the duration, by kinetic parameter adjustment.…”

Modeling on a Three-Way Catalyst Used in Series Hybrid Electric Vehicles Focusing on Its Catalytic Behavior at Cold Start

“…The former is suitable for expressing actual phenomena more precisely, , whereas the latter, which generally has a lighter calculation load and higher robustness for calculation stability, tends to have been preferred more in recent studies due to increasing needs for performance simulation in transient mode. − Limiting the scope to SHEVs, many investigations have focused on power control systems and fuel economy, whereas those focusing on emissions are scarce. Therefore, in our previous studies, we performed a vehicle test on a commercially produced SHEV and investigated the attributes of the engine emission. , Then, in terms of close-coupled TWCs (cc-TWCs), a numerical 1-D model that can achieve favorable reproducibility for light-off test results under a wide range of λ conditions, including amounts of byproducts (such as NH 3 and N 2 O), was built by introducing kinetic parameter control (KPC) along with λ. KPC is a control method that involves switching rate constants along with λ by providing two or three sets of kinetic parameters and λ threshold values to switch them for each global reaction. Essentially, although the rate constant must be immutable, it is nearly impossible to express the whole purification mechanism of TWCs with approximately 30 global reactions because they have not been elucidated sufficiently.…”

“…Therefore, in our previous studies, we performed a vehicle test on a commercially produced SHEV and investigated the attributes of the engine emission. 9,10 Then, in terms of close-coupled TWCs (cc-TWCs), a numerical 1-D model that can achieve favorable reproducibility for light-off test results under a wide range of λ conditions, including amounts of byproducts (such as NH 3 and N 2 O), was built by introducing kinetic parameter control (KPC) along with λ. KPC is a control method that involves switching rate constants along with λ by providing two or three sets of kinetic parameters and λ threshold values to switch them for each global reaction. Essentially, although the rate constant must be immutable, it is nearly impossible to express the whole purification mechanism of TWCs with approximately 30 global reactions because they have not been elucidated sufficiently.…”