Current Journal of Applied Science and Technology

Energy flows and energy efficiencies in the operation of a modern automobile are development expressed and corresponding on  reduction of pollutant emission from spark ignition (SI)  engines is desirable due to reduce the highly impact on the green environment, the trend toward high engines efficiency has led to new implementation of more intelligent engine thermal management (ETM) systems. However, the present work aims to clear the effect of different cooling systems and operating parameters of the SI engine on their engine performance and emission characteristics. An active coolant control (ACC) as well as of engine ETM has been realized using a variable-speed electrical pump, and a variable-position smart valve which controls the fluid flow rate distribution between the radiator and its bypass line to better regulate heat rejection. Experimental engine cooling systems have been operating assembled two different cooling systems (conventional or ACC). The Nissan SI engine was used as the experimental set-up and equipped with exhaust gas analyzer, Thermocouple sensors and magnetic pickup transducer to measure the exhaust emissions, coolant temperature and engine rotational speed respectively. The measurements were conducted at different engine speed and load torque. The results indicate that most of the carbon monoxide (CO), carbon dioxide (CO₂), and unburned total hydrocarbons (THC) emission appears at higher load as well as near the coolant temperature. Nitrogen oxides (NOx) emission was observed to increases because higher coolant temperature contributed to raising combustion temperature, the results show that the arrangement of ACC flow rate and operation in idle state is very effective to reduce exhaust emissions. The assessment results of the experimental tests revealed that warm up period with ACC was decreased by 31%, In addition, CO₂, CO, THC, and NOx, of SI engine with ACC were reduced by 11%, 13.5%, 8.4%, 6.2%, and 26.0%, respectively.