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Truck and car manufacturers are required to satisfy certain emission standards while driving regulatory prescribed driving cycles on a vehicle chassis dynamometer. In India, the requirement is to use the regulatory Modified Indian Driving Cycle (MIDC), derived from the European Driving Cycle. The MIDC is a modal driving cycle with protracted periods at constant speed and uniform acceleration and deceleration patterns. It does not emulate typical road driving. In this study we instrument vehicles with off-the-shelf On-Board-Diagnostics (OBD) loggers to record actual drive data. The recorded vehicle speed profiles are then used as inputs for the vehicle simulation model we develop. The simulation model uses vehicle speed as an input and then calculates power required at the wheel, gear box, and Internal Combustion Engine (ICE) for the vehicle to achieve the measured speed profile. We use Willans Approximation to model the ICE fuel flow based on torque and speed.

Commercial Heavy vehicles (CHVs) are an efficient and reliable link between marine, railroad, and air transportation nodes. The vehicle braking power imposes an important constraint in the allowable vehicle speed. The compression brake augments the vehicle retarding power and is currently typically used as an on-off device by experienced drivers. Hardware and software advances allow modulation of the compression brake power through variable valve timing, and thus, enable integration of the compression brake with service brakes. To analyze how much the compression brake affects vehicle speed during braking, we develop a crank angle engine model that describes the intrinsic transient interactions between individual cylinder intake and exhaust gas process, turbocharger dynamics, and vehicle dynamics during combustion and variable brake valve timing. The model is validated using experimental data.