内燃机-清洁的废气取决于催化转化器。叉车的严格要求将对环境的有害废气排放降至最低。通过催化转化器清除“一氧化碳和烟灰”等有毒气体。
所使用的两种基本转换器类型为：
•干式排气（催化转换器）
-与汽油IC发动机一起使用-排气在后燃烧器中燃烧。达到指定温度后，有害气体会通过氧化过程进一步减少。
•湿排气（催化转化器）
-在柴油机中使用-废气被迫通过水浴，该水浴会过滤烟灰并减少这些发动机消耗的难闻香气。之后，废气被强制进入后燃烧器进行进一步净化。

       IC engine - clean exhaust depends on a catalytic converter. The stringent requirement for forklift trucks minimises the release of harmful exhaust to environment. The toxic gases "carbon monoxide and soot" are cleaned via a catalytic converter.
Two basic converter types used are:
• Dry exhaust (catalytic converter)
- used with gasoline IC engines - The exhaust is burned in an after-burner. After reaching a specified temperature the harmful gases are further reduced through an oxidation process.
• Wet exhaust (catalytic converter)
- used in Diesel applications - The exhaust gas is forced through a water bath which filters soot and reduces the unpleasant aroma expended by these engines. Afterwards the exhaust gas is forced into an after-burner for further purification.