这时，发动机已无法通过转速来调节系统的供热量。

At this time, the engine speed has been unable to adjust for the heat system.

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并应根据供热系统选择有效的调节阀。

And according to the system make a choice for effective regulating valves.

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并应根据供热系统选择有效的调节阀。

And according to the system make a choice for effective regulating valves.

youdao