Dieseloil detergency can drastically influence the performance of diesel engine, which has great effect on vehicle emissions. In order to control the diesel vehicles emission, it is necessary to supervise commercial diesel. Diesel detergency fast simulator can make the detergency evaluation easier, which is an important method to supervise diesel. Distillation range of diesel is the essential base parameter for detergency fast simulator to set working condition. Travelling controller is used to optimize distillation range determination device, which make the detergency detection more intelligent and more time saving. After optimization, distillation range determination device can automatically test and correct temperature, control heating and cooling, and test liquid level by infrared, etc. Therefore, it can reduce operator’s tasks and errors. These optimization designs make it more convenient to operate the detergency detector on mobile monitor vehicle, which is beneficial to supervise commercial diesel rapidly.