Experimental investigation of cold start emission using preheating system on the exhaust line at the idle conditions on a spark ignition engine

Abstract

In an ideal conditions, three-way catalytic converters have a structure that will convert almost all of the harmful exhaust emissions. However, these conditions are not valid for cold start and idle conditions. Especially in cold weather, people wait for a while at the idle speed even though it is not a good way to warm up the engine. In this period, since the required temperature to reach light-off values are not provided, the emission released to the environment is at the highest level. The effects of preheating of the catalytic converter have been investigated in order to minimize the exhaust gases emitted under cold and idle working conditions and to meet the Euro standards as soon as possible after the emission release starts. In this experimental study, preheating of 1060, 1253 and 1493 Watt energy was applied to the exhaust line before the three-way catalytic converter at the cold start and idle conditions. Preheating was started when the engine started running. In the experiments, temperature and emission values were obtained at the catalytic converter inlet and outlet at idle conditions (1000 rpm) for about 430 seconds. The effects of inlet temperatures of exhaust gases on HC and CO emission behavior and converter conversion efficiency were investigated. When 1060, 1253 and 1493 Watt preheating are applied to the exhaust line, the times for reaching the light-off for HC and CO emissions occur at 395, 295, 220 and 369, 277, 200 seconds, respectively. However, when preheating is not applied, the catalytic converter has not been able to reach the light-off within the specified time. Finally, the EURO VI standard could not be achieved for the specified period without preheating. However, when the preheating load was set to 1493 Watt, EURO VI standards were achieved at the end of 310 and 285 seconds preheating times for both HC and CO emissions.