Plumbed into the exhaust stream of many diesel powered off-road machines you buy today is either a diesel oxidation catalyst (DOC) or a diesel particulate filter (DPF) or both.
While there has been much talk and concern over these changes, the reality is that these engines and their emissions control systems are here to stay. Tier 4 Interim engines are more expensive. But for many of these engines the increased costs will be partially offset by gains in fuel efficiency and power. They are more complex, yes; but vastly better for the air we all breathe.
Your maintenance protocols will change little on these new engines. DOCs and DPFs, however, were not just stuck on to the exhaust ports of these engines as an afterthought. So when buying new equipment today you need to know:
• Does this machine have a DOC or a DPF – or both – selective catalytic reduction, or none of the above?
• What changes have been made to the engine upstream of the exhaust?
• How does my maintenance change as a result?
