Compoundventilation mode is adopted in this system, so that natural draught and mechanical ventilation can alternately function under different conditions.
采用混合式通风方式，自然通风和机械通风可以依据不同的条件交替运行。
2
Based on experimental data, puts forward a series of compound factors influencing ventilation effectiveness, and develops empirical formulas for predicting the ventilation efficiency.
根据大量的实验资料，分析提出了影响通风效率的若干复合因素，得出了预测置换通风效率的经验式。
3
The positive crankcase ventilation valve and gas caps with air-pollution control valves reduce volatile organic compound loss.