Performance Research On Swirling Inlet Combustion Chamber Of Minitype Evaporative Vehicle Heater

As an independent system of automobile, the vehicle heater is able to effectively improve the cold start performance of engine in low temperature environment. Also, it can be used to carriage heating and window defrosting. With the development of vehicle industry and the increasingly stringent emission regulations, vehicle heater has been supplied and applied widely. At present, most vehicle heaters are applied in the north part of the country where it’s cold weather in winter, assembled in passenger cars, buses and tanks and other military vehicles. The vehicle heater, which has a compact structure, a high thermal efficiency, a small size and an intelligent electronic control system, is in need of further optimization. The research object of this article is the YJH-Q5B evaporative type fuel heater. In order to reduce or eliminate the Carbon deposition in the primary combustion chamber, we made some modifications to the swirling inlet structure.Firstly, the Fluent software was used for numerical simulation of the original heater and the chambers with modified swirling structure to get the velocity and relative pressure of gas flow. Through the gas flow field analysis of the original combustion chamber, the effects of structural parameters on gas flow, mixture, burning and carbon deposition formation were analyzed. We found the reason of Carbon deposition formation and improved the structure of combustion chamber. The combustion air, which passes through the swirling inlet holes, is strongly swirling in the primary combustion chamber. It helps gas mixture and entrainment of gas on the wall. Also, we analyzed the influence of diameter, axial distance and serial eccentricity on gas flow.Then, air-fuel ratio characteristics experiments were carried out on YJH-Q5B evaporative type vehicle fuel heaters with the original and swirling inlet combustion chamber. We got the thermal power, thermal efficiency and exhaust temperature on different air-fuel ratios and mapped the air-fuel ratio characteristics curves. With the numerical simulation results and test data, the best combination of diameter, axial distance and serial eccentricity was found. The comparison and analysis between the improved and the original heater test results proved that the swirling inlet heater can reduce Carbon deposition and improve thermal power and thermal efficiency in varying degrees.Moreover, several different tests were carried out to study the influence factors on heater’s performance. Based on the contrast test of oil supply frequency, we analyzed the heat transfer ability of heat-exchange facility and the influence of oil supply frequency on the performance of heater. In addition, we summarized the influence of water flow on the performance of heater from the test of different water flow and found the best combination of water flow and water temperature difference to let the thermal power and thermal efficiency maximizing. The temperature field was obtained by measuring the temperature of the combustion chamber. Through the performance test of circulating water pump, the characteristics of the pump were gained.