Parametric Calculation and Significance of Engine Dynamic Torque in Performance Benchmarking of a Vehicle 2019-28-0028
The automotive industries around the globe is undergoing massive transformation towards technological capability to meet stringent legislative norms on fuel economy and emission. It is a challenging process to meet the regulatory standards without compromising on performance. The torque delivered by the engine at wide open throttle position in a transient condition from low idle to higher engine rpm is known as dynamic torque, which always need not to follow the defined FTP curve. The engine dynamic torque plays a crucial part in performance benchmarking of a vehicle as a visualization parameter to set the project targets. There exist a few methodologies to measure the engine brake torque like direct measurement using torque transducer which adds complexity and cost to the vehicle, ECU measured torque based on amount of fuel injection and empirical calculation using known engine speed. Since every method is having their own capabilities, limitations and none of them are efficient to capture real transient torque behavior of an engine. This work elaborates about the role of dynamic torque on performance improvement and benchmarking of an engine. A distinct approach has been employed to measure dynamic torque of the engine, which counter calculate the dynamic torque from vehicle speed at individual gears taking inertial resistance into an account. An experimental automotive engine was selected, and performance benchmarked against competitor engine to set project targets using 1D simulation. At every developmental stage, turbocharger strategy has been optimized to get better transient torque delivery characteristics of the engine. Later the iterated dynamic torque and corresponding performance numbers has been validated against measured test results. The outcomes are found to be giving good correlation which makes the approach efficient and executable for better prediction of performance targets in early developmental stage of a vehicle.