Improving the performance and emissions of a four-stroke, water-cooled, di diesel engine by increasing inlet air temperature

Abstract EN

The inlet air temperature of a diesel engine plays a dominant role in its efficiency as it affects the combustion parameters, provided the engine characteristics are suitably adjusted.

this study investigates the effect of inlet air temperature on the performance and emissions of a single-cylinder, four-stroke, water-cooled, direct-injection diesel engine.

inlet air was preheated up to 90 ⁰C and its impact was observed using the diesel-RK software simulator under constant engine speed and variable load conditions.

air-preheating increases the physical and chemical delay rates-i.e., it accelerates the droplet vaporization and combustion rates.

however, this also reduces its density, thereby lowering its mass flow rate and cycle efficiency, which is counterproductive.

therefore, the inlet air density must be increased to its original value beforehand to yield the full benefits of air-preheating.

furthermore, the effect of increased fuel flow rate at 30% of its rated value was also investigated; combined with increased air density, this caused a spike in the rated power, leading to improvements in the engine performance and combustion efficiency.

these results show that preheating the intake air by increasing the fuel and intake air mass could improve the power-to-mass ratio of existing engines and reduce its pollutant emissions.