Hybrid Topology Selection & Optimization of a Compact SUV to Meet Future CO2 Norms - an Indian Case Study

Rising environmental concerns and stringent emissions norms are pushing automakers to adopt more sustainable technologies. There is no single perfect solution for any market and there are solutions ranging from biofuels, green hydrogen to electric vehicles. For Indian market, especially in the passenger car segment, hybrid vehicles are favoured when it comes to manufacturers as well as with consumer because of multiple reasons such as reliability, performance, fuel efficiency and lower long-term cost of ownership. For automakers planning to upgrade their fleets in the context of upcoming CAFE III (91.7 g CO2 / km) & CAFE IV (70 g CO2 / km) norms, hybridization emerges as the next natural step for passenger cars. Lately, various state governments have also promoted hybrid vehicle sales by offering certain targeted tax breaks which were previously reserved for EVs exclusively. Current study focuses on various parallel hybrid topologies for an Indian compact SUV, which is the highest selling and fastest growing segment in India. The selected SUV with curb weight ~1315 kg has a 1.2 L turbocharged gasoline engine with peak power and peak torque of 88 kW and 170 Nm respectively. Simulations of various low voltage (LV) and high voltage (HV) hybrid topologies like P0 LV (base scenario for 2030), P0P2 LV, P0P2 HV and P0P4 HV are performed as per Worldwide Harmonized light vehicle test procedure (WLTP) in line with upcoming CAFE norms. Results are analysed to gauge performance (acceleration, gradeability) and fuel consumption. Regeneration and torque boosting capabilities of various hybrid topologies are also compared analytically based on simulation results. Gaussian optimization methodology is employed to systematically optimize powertrain configurations and control strategies to maximize fuel efficiency.