Reduction of particulate emissions in diesel hybrid electric vehicles with a PMP-based control strategy

Abstract

Over the last decades the pollutant emissions of passenger-car diesel engines have been significantly reduced by the emission standards, but it is known that in real driving conditions these vehicles significantly exceed the regulation limits. For this reason, an increasing number of cities and municipalities already are or are thinking about banning diesel cars to cope with local air pollution. This aspect together with the upcoming EURO 7 air pollution regulations are expected to push diesel cars out of the market, because of a too-much demanding requirement on the reduction in particulate and carbon dioxide emissions. The only way to make these cars keep a share in the automotive market is probably their hybridization. The aim of these paper is to propose a control strategy for the power split in diesel-hybrid vehicles, aimed at minimizing particulate emissions and controlling the battery state of charge simultaneously. To this aim, a supervisory controller, based on Pontryagins Minimum Principle, is designed for on-line energy management optimization of a Diesel Plug-in Hybrid Electric Vehicle with a parallel architecture. The proposed strategy focuses on the reduction of particulate emissions that represents a major issue to meet emissions standards in such vehicles. In this study a methodology based on software in the loop simulations is applied in order to properly tune the proposed energy management strategy and to understand the overall powertrain performance. This work demonstrates the potential of using the hybrid architecture to limit particulate emissions even under real-world-like driving cycles.