Abstract
With improved engine technologies, vehicle styling and spending capacity, each year many number of vehicles hit Indian roads. This increase has implications like Greenhouse gas emissions, resulting into ozone layer depletion, global warming and depletion of fossil fuel at very fast rate. Thus, it has become essential to control CO2 emissions. The most effective way is to improve vehicle fuel economy and reduce CO2 emissions, with the help of some promising technologies like Hybrid Electric Vehicles (HEV), Full Electric Vehicles and Fuel Cell Vehicles (FCV). In a price sensitive market as in India; vehicle selection is driven by, fuel economy (FE) and cost of the vehicle, HEV will prove to be better solution, compared to Electric Vehicles (EVs) considering unavailability of charging infrastructure. The paper focuses on the design, development and performance evaluation of supervisory controller for full parallel HEV configuration. A light commercial vehicle which is the ideal candidate for this application is considered for converting its base diesel version into full parallel HEV configuration. Major thrust is given to get fossil fuel economy improvement on standard and city driving cycles in the range of 20-28% after hybridization while meeting base vehicle performance as same or better. Various topologies viz P0, P2, P2.5, P3 and P4 are evaluated using Modified Indian Driving Cycle (MIDC), WLTP and City Driving Cycle (CDC) (also called as Pune City Cycle (PCC)) to arrive at best possible configuration in terms of target performance with less complex architecture. Supervisory controller is built on simple rule based technique, Engine ON-OFF strategy, fuzzy logic and dynamic program based are evaluated and finally converged with one of them which is comprehensive but simpler to implement it. Thus with degree of hybridization of 35% , P3 configuration, supervisory controller based on dynamic programming technique and by using 7 speed AMT based power train. FE improvement in the range of 25-30% is achieved in virtual environment even by considering increased GVW (Gross Vehicle Weight) by 88 kg while maintain max velocity, acceleration in different gears, gradability at par with base vehicle. By using derived engine alone operating points while negotiating MIDC which is an outcome of supervisory HEV controller, tractive force and vehicle speed are computed and applied on chassis dynamometer to operate the vehicle with those limited new operating points. This new engine operating points includes engine alone operation, engine contribution during hybrid modes and for charging the PPS when SOC falls beyond the set limits. During pure EV operations and start – stop scenario, engine kept at idling and its fuel consumption is recorded separately. With this an intermediate technique, fossil fuel economy improvement over base by 27-29% is achieved even after reducing losses that may occur during pure electric mode of operations. This route has helped in giving confirmation and assurance about getting target FE improvement on experimental level before actually building real prototype which has its own time and cost implications.