Impact of the JAZARI technology piston motion profile on the indicated thermal efficiency of a 4-cylinder diesel engine

Abstract

As fuel economy and consumption become global concerns, engine developers strive to reduce fuel consumption. However, due to complexity and development challenges, only a few new engine technologies have been introduced recently. Nevertheless, the market demands more efficient engines, prompting a focus on new mechanisms. This study evaluates a theoretical 4-cylinder Compression Ignition (CI) diesel engine implementing the JAZARI mechanism, which alters piston speed near top dead center TDC claiming a faster combustion, reduced duration, and improved power output. The evaluation compares indicated thermal efficiency, torque, and fuel consumption using a 1-Dimensional simulation model based on the first law of thermodynamics., which then was calibrated using testing data obtained from an engine test cell dynamometer. Two load cases at 2500 RPM were examined, The simulation results indicate that when using the JAZARI mechanism compared with the calibrated conventional mechanism engine, an increase of 1% in thermal efficiency and 2.5% in indicated torque is seen with only reducing the injection duration and timing to fit the JAZARI mechanism piston motion profile, and when aiming for maximum indicated thermal efficiency it was increased by 1.2% and 3.1% in indicated torque, the final results case indicated that when using the JAZARI mechanism, the engine reached the same indicated torque of 295 N.m, with same indicated efficiency of 45.8% with a peak firing pressure of 155 bar, which is almost 30 bar less than the conventional mechanism case, meaning the ability to boost the JAZARI engine with less risk on the engine internals is an advantage.