1、 Function of biogas engine coolant

沼气发动机正常工作温度为65-70°，比普通的发动机要低15-20°，过高的发动机温度会使混合气体爆燃，影响发动机正常运转同时会加速发动机油蜕变，使之产生积碳，容易形成油膜决裂，光滑不良，磨损加剧。因而，运用发动机冷却液对沼气发动机停止恰当降温尤为重要，能够保证发动机正常工作。

The normal working temperature of biogas engine is 65-70 °, which is 15-20 ° lower than that of ordinary engine. Too high engine temperature will deflagration the mixed gas, affect the normal operation of the engine, and accelerate the transformation of engine oil to produce carbon deposition, which is easy to form oil film cracking, poor smoothness and intensified wear. Therefore, it is particularly important to use engine coolant to stop and properly cool the biogas engine, which can ensure the normal operation of the engine.

但假如发动机的温度太低，冷却过度，也会产生反作用，使发动机盖的热量损失加大，不利于可燃混合气体的构成和熄灭，并招致发动机油粘度变大，摩擦损失增加，形成发动机有效功率降低。

However, if the temperature of the engine is too low and the cooling is too excessive, it will also have a reaction, which will increase the heat loss of the engine cover, which is not conducive to the composition and extinction of combustible gas mixture, increase the viscosity of engine oil, increase the friction loss, and reduce the effective power of the engine.

在实践运用过程中，普通应用冷却液的小循环和大循环处理沼气发动机的冷却光滑问题， 使发动机得到适度的冷却，从而使其坚持在适合的温度范围内工作。通常关于沼气发动机的水冷却系统，当缸盖冷却水套中的冷却液温度到达60°左右时，大循环启动，可确保沼气发动机正常工作。

In the process of practical application, the small cycle and large cycle of coolant are commonly used to deal with the problem of smooth cooling of biogas engine, so that the engine can be moderately cooled, so as to make it work within the appropriate temperature range. Generally, for the water cooling system of biogas engine, when the coolant temperature in the cylinder head cooling water jacket reaches about 60 °, the large cycle is started to ensure the normal operation of biogas engine.

二、水介质能否能替代发动机冷却液

2、 Can water replace engine coolant

在实践运用中用户常常疏忽发动机冷却液的运用，而简单的用水作为发电机组的冷却介质。随着发电机组的运转冷却水损耗严重，需求频繁补加水分，且运用一段时间后就会结垢，招致发电机组冷却效果降落，发动机运转温度升高，影响发电机组的正常发电。

In practice, users often neglect the use of engine coolant, and simply use water as the cooling medium of generator set. With the operation of the generator set, the cooling water loss is serious, the water needs to be added frequently, and scaling will occur after use for a period of time, resulting in the reduction of the cooling effect of the generator set and the increase of the engine operating temperature, affecting the normal power generation of the generator set.