Towards Integrated Powertrain Control: Thermal Management of NG Heated Catalyst System

Towards Integrated Powertrain Control: Thermal Management of NG Heated Catalyst System — The conversion efficiency of catalytic converters is mainly defined by the temperature range wherein they are operating. Traditionally, ignition retard has been used to reduce the light-off time of the catalyst. This is however associated with a fuel penalty. With increasing vehicle electrification, external heating facilities present an alternative, especially for hybrid vehicles. Nevertheless, system complexity of hybrid vehicles prevents engineers to evaluate possible heating technologies with respect to traditional solutions. This paper evaluates the application of an electric heated catalyst on a hybrid vehicle equipped with a natural gas (NG) engine. The effect of system sizing on light-off time and fuel penalty is determined, using Integrated Powertrain Control (IPC) analysis techniques. By means of a case study, the IPC concept is explained by comparing the fuel penalty for electric heating with that of ignition retard. In this process, a mix of simulation and test data were combined, forming the foundations for future control developments of a suitable light-off strategy.