Experimental Analysis on Internal Flow Field of Enhanced Heat Transfer Structure for Clean Gas Bus Engine Compartment

Heat dissipation efficiency of clean gas bus cabin is undermined by both inappropriate design of air passages in the engine compartment and the excessively long paths for hot air to be discharged from the cabin. In order to verify the temperature field homogenization enhanced heat transfer method (TFH) in the engine compartment of clean-gas-bus, a temperature field experimental system for LPG city bus (LPGB) engine compartment based on infrared imaging technology was built. The temperature field in the semi-enclosed space engine compartment was non-interfering, visualizing and continuously measured. At the same time, under the five working conditions of the LPG engine, 16-channel temperature sensors were used to collect the temperature of key components changing with time. The experimental results showed that compared with the typical structure, the temperatures of the radiator inlet water and the high-temperature exhaust manifold of the enhanced heat transfer structure decreased by 10.8% and 25.4% respectively. The engine compartment with the enhanced heat transfer structure had the following characteristic of “minimum temperature gradient in core flow region and maximum temperature gradient on the thermal boundary”, which conforms to the TFH optimization model which helped to strengthen the heat dissipation in the cabin.