汽油机台架冷却系统的改造

为汽油机低水温台架试验而改造冷却系统。以水箱恒温水对发动机稳定工况大循环冷却系统进行实验，得出冷却水温不变的结论。据此叙述系统主要改造技术和水温控制原理。系统采用旁通阀手动排泄适宜的进箱前冷却水量，用浮球阀自动向箱内补充等排泄量的冷水，使箱内水温稳定，并进行负荷特性试验与性能分析。结果表明，发动机在转速3500r／rain各水温控制精度≤±O．3℃，满足试验要求。此冷却系统运行可靠，实现在40～96℃之间任一冷却水温控制。

A Transforming Cooling System of Gasoline Engine on Test Rig

The cooling system was transformed for gasoline engine bench test at lower coolant temperature. The authors made a conclusion of steady cooling water temperature after the big-circle cooling system of engine stable condition was experimented with constant water temperature in tank, herewith recounted main transforming technologies and coolant temperature control principle. The water temperature was stabilized in tank by draining manually suitable rate of flow of cooling water before flowing into tank with a bypass valve and adding automatically colder water equal to drainage one to tank with a float valve. The performances of the system were analyzed after the engine load characteristic test. The results show that the coolant temperature control accuracy of each point is within ≤0.3℃ at 3 500 r/min engine speed and satisfies test needs. The system runs reliably and achieves either of points of coolant temperature control between 40℃ and 96℃.