How to avoid the particulate filter blues.

How to avoid the particulate filter blues.

Opinion: Diesel Forklift Trucks.

How many owners of diesel forklift trucks purchased within the last few years are fed-up with the hassle, cost and downtime of running the regeneration cycle on their diesel particulate filters (DPF) every 25 hours or so? If you’re one of them, you’re not alone, there are a great many out there, and the numbers are growing by the day.

However, this irritating, time-wasting, and costly process could be so easily avoided if buyers were better informed before purchase. The problem is, most forklift truck manufacturers do not make prospective customers aware of the fact that there are engines available that do not need diesel particulate filters. Perhaps, for those manufacturers lacking the engine technology it’s hardly surprising that they keep it a secret. But they are doing their customers a great disservice.

The issue has only arisen over the last few years, following the introduction in 2014 of new EU emissions standards for non-road vehicles. The stringent Euro-Stage IIIB standards for all diesel engines over 37kW, and Stage IV for those over 55kw, require NOx, HC and particulate material (soot) exhaust emissions from new engines to be reduced by a substantial 90% compared to the Stage III standards they replace.

This has posed a major problem for the manufacturers. As the vast majority of forklift makers do not build their own engines, the solution adopted by the industry, in general, is to adapt ill-suited automotive engines and reduce the amount of NOx by lowering the combustion temperature using cooled exhaust gas to dilute the amount of oxygen in the combustion chamber. But, there is a big penalty. Soot is increased which requires the engine to have a diesel particulate filter fitted to prevent the soot being emitted.

As those having purchased a new forklift fitted with a diesel particulate filter will know to their chagrin, part-and-parcel of having such a filter is that it has to be recharged at alarmingly regular intervals. This is a lengthy process that for most users must be performed once or twice a week and requires the truck to be taken out of service and the engine to be revved at full engine RPM for about 20 minutes to half an hour, in order to burn the soot that has collected in the particulate filter. Huge amounts of fuel are used in the process and the truck is not available for duty – increasing downtime and significantly impacting productivity. Then there are the costs associated with the burning of extra fuel and associated maintenance issues, not to mention the sheer inconvenience of the whole lengthy, repetitive process.

What’s more, how many forklift drivers are tempted to ignore the red warning light that pops-up on the dashboard when regeneration is required? Failure to respond swiftly can result in machine shutdown, needing an expensive call-out of an engineer to perform forced filter regeneration. Imagine the costs and the downtime waiting for an engineer – perhaps you don’t need to imagine it!

But all this could so easily be avoided. There are only three forklift truck manufacturers who have diesel engines on the market that do not require diesel particulate filters to comply with Euro-Stage IIIB and Stage IV standards. Two of them can only offer solutions in limited product ranges. The other, Doosan, has a full range from 2.0-tonne capacity across all diesel powered counterbalance trucks up to 25-tonnes.

Doosan Industrial Vehicles’ revolutionary approach to the new emissions challenge was to anticipate the legislation by developing a highly innovative new diesel engine specifically for non-road use. As part of the $21bn Doosan engineering conglomerate, the industrial vehicle division was uniquely positioned to tap into the rich resources and ‘in-house’ expertise of Doosan’s Infracore Engine Division. The result was a groundbreaking new design, created for the specific needs of industrial applications – a concept far removed from the ‘sticking plaster’ approach taken by most forklift truck manufacturers with their poorly adapted diesel engine formats borrowed from the automotive sector.

Clever design of the combustion chambers and piston heads, coupled with an ingenious fuel injection system, results in a cleaner burn with Doosan’s G2 engine, producing much less soot. Critically, the need for a Diesel Particulate Filter has been engineered out.

In September 2014, Doosan’s award-winning ‘DPF-free’ G2 engine was introduced to the market bringing lower fuel consumption, longer maintenance intervals and maintenance-free after-treatment systems – providing best-in-class performance on fuel economy and emissions while exceeding all Euro Stage lllB and Stage IV legislation.

Payback on the G2 is faster than for any other engine in this class. In tests at Millbrook Proving Ground, Doosan’s G2 engine recorded fuel consumption reductions of more than 30% compared with the previous model, making fuel economy an outstanding feature of the new design.

So, the secret is out. Performance, fuel economy and emissions compliance can all be attained from a new diesel forklift truck without the need to endure the frustrations, downtime and costs associated with DPF regeneration – heralding an end to the particulate filter blues.

Paul Watson is UK Sales Director at Doosan Industrial Vehicles UK Ltd.

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