Temperature Testing and Analysis of the Vacuum Advance Disconnect Exhaust Emission Control.

摘要

The purpose of this study was to examine the temperature changes on vehicles after vacuum spark advance circuits were disconnected. The vacuum advance disconnect (VAD) technique is a simple exhaust emission control method capable of reducing NOx emission from used cars but the feasibility of driveability and operational problems needed investigation. Effects of the VAD on engine temperatures were observed in 200motor vehicles; 100cars had no other emission control,and 100had other systems as original equipment. For controlled vehicles,the coolant temperature was usually unchanged,but seven overheated because of the VAD;six uncontrolled cars boiled over because of the VAD. Engine oil temperature usually decreased slightly with VAD;oil temperature in two vehicles with VAD increased excessively. Exhaust temperatures increased 10% with VAD,under load,and about 5% with VAD at idle;they were slightly higher for controlled than for uncontrolled cars. Temperatures generally increased as the ambient temperature increased.