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Ask A Darley Engineer

By Tim Dewitz, CMfgT, Darley Senior Engineer

What is the impact of recent EPA changes on diesel engine driven pumps?—Bill Davidson, Skeeter Brush Trucks

Tier 4F engine with diesel Oxidation Catalyst (DOC) exhaust after-treatment.

For the past few months, I have been answering the same question, relative to availability of EPA-compliant diesel engines: “What diesel engines are available for sale in the U.S. Marketplace?”

For many years, the U.S. marketplace, along with much of the world, has been transitioning to diesel (NONROAD COMPRESSIONIGNITED) engines that emit less particulate matter and fewer harmful gases in the exhaust. In the U.S., the EPA has developed 40 CFR 1039, a set of guidelines controlling the emissions from diesel engines. I am neither a lawyer nor a legal expert, so I encourage readers to go to the EPA Web site listed at the bottom of this article and review the guidelines for themselves.

TPEM (Transition Program for Equipment Manufacturers), sometimes referred to as the “Flex program,” allowed a transition period for engine and equipment manufacturers to finalize their designs to be compliant with the 40 CFR guidelines. In many power categories, this has already come to an end. For the 19-kW to less than 130-kW (25.5-174.3 hp) categories, this ends at midnight on December 31, 2018.

Tier 3 engine – no exhaust after treatment.

Engine suppliers are able to still supply “Flex” engines for us to build product for sale in the U.S. market within 2018. Anything above 130 kW or below 19 kW already has to be Tier 4 (final) compliant. Some municipalities already require engines to be Tier 4 final compliant (or better). Each engine manufacturer has its own cutoff timeline for final orders and deliveries. Some have released statements indicating that they will not take any new orders for “Flex” engines after May 2018, with delivery of the engines up until November 2018. This means that we can order the engines up until that cutoff date, and they will supply the “Flex” engines to us with their normal lead times (or delayed delivery if we request at time of order) until November. We then have time to build the engine into product before the end of the 2018 calendar year.

Tier 4 final compliant engines typically will have exhaust after-treatment that increases the engine’s cost and physical size. In most cases, the location of the air cleaner and the exhaust after-treatment is not able to be changed without recertifying the unit. The exhaust normally can be extended after the treatment, as long as the back pressure increase is within the engine manufacturer’s specification. For some installations, an application review may be required by a representative of the engine manufacturer.

Visit Title 40 Part 1039 at www.ecfr.gov for more information.

For more information on W.S. Darley & Co., visit www.darley.com.

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