A Tough Climb To Tier 4
- Published: Tuesday, 06 April 2010 06:50
As 2011 approaches, Tier 4 Interim looms over heavy equipment manufacturers. This phase of the Environmental Protection Agencyís crusade for zero emissions impacts 174- to 751-horsepower vehicles; regulations for 75- to 130-horsepower engines start in 2012. These regulations aim to significantly limit emissions of nitrogen oxides, particulate matter and carbon monoxide.
Mobile equipment has been impacted dramatically, as Tier 4 is calling for new technology beyond internal engine components. Unlike the prior EPA standards, Tier 4 Interim demands drastic modifications to machine designs. Engine compartments are being increased to accommodate exhaust after-treatment components; costs for the end users and maintenance responsibilities also will increase.
ìThere will be increased costs,î says Joe Suchecki, director of public affairs for the Engine Manufacturers Association. ìHow much is passed onto the consumer will obviously depend on market conditions.î He notes a down economy and a surplus of unsold Tier 3 machines.
EMA represents the engine manufacturing industry on domestic and international public policy, regulatory and technical issues. The primary function of EMA is to advance its member companiesí interests on emissions and air-quality issues before legislative and regulatory bodies. Suchecki explains the two technologies, on which engine manufactures will rely.
The first technology reduces diesel particulate matter with an after-treatment filter. It is the same technology that has been employed by on-highway diesel engines since 2007, Suchecki says. The filter traps particles that are later burned off, transforming them to carbon dioxide.
These filters are either active of passive. Passive systems must be activated manually. The active filters rely on engine software and sensors that regulate a regeneration cycle. This is a combustion process that transforms the carbon and hydrocarbons stored in the particulate filter into simple carbon dioxide. Addressing carbon-dioxide emissions will be in the next round of regulations, Suchecki says.
Everything does not combust completely during the conversion to carbon dioxide, however, so there is a buildup of ash. This ash must be cleaned from the filters, which adds to engine maintenance. Manufacturers will set their own hour intervals for maintenance.
Excessive ash inside the engine increases back pressure and clogs the exhaust system, which can cause engine problems. Itís also safe to say that the warranty would be impacted if this maintenance is ignored. Suchecki says that fortunately maintenance is a fairly simple process of back flushing the system with air.
ìYou have to combust these particles. There really is no other way to take care of them,î he says. ìThis is the best technology, and everyone agrees on that.î
There will be some variation, however, when dealing with nitrogen oxide emissions. The complexity of this task is what called for an interim period. Suchecki says there was a feeling throughout the engine industry that the final rule could not be met without dramatic and costly modifications.
Some options still are not cost effective or proven, Suchecki says. Most OEMs will first conform to interim standards that call for a 50% reduction of nitrogen oxides before the 90% mandatory reduction takes effect in 2015. However, others might adopt the final standards at the start of 2011.
The most likely technology will be selective catalytic reduction , another after-treatment system. This technology already has been put to the test on stationary engines to reduce nitrogen oxides. Essentially, it is a catalytic converter, but the exhaust must be treated with a reductant. The reductant actually is urea, which is more commonly called ìdiesel exhaust fluidî that must be injected into the system. For the OEM, it means the addition of an injection system and a fitted tank.
The selective catalytic reduction creates the added burden of maintaining reductant levels. Suchecki says that EPA has been very concerned by the potential failure to maintain these fluid levels. Without the reductant, the machine falls out of compliance and emits excessive nitrogen oxides.
It is likely that the EPA will require OEMs to incorporate technology to police the end user. It might start with a simple warning light, but unlike seat belt lights, the operator would not have the freedom to ignore it. If the operator does not heed the warning, the engine may drop into a mode that prevents operation above 30 mph. If the warning continues to be ignored, there likely will be technology to kill the engine completely until the reductant is replenished.
Exhaust gas recirculation is an alternative to the selective catalytic reduction, at least for the interim, that is being employed by John Deere Power Systems. The company says the urea injection system is more costly and the chemical is not available worldwide. Another downside is that it freezes. However, John Deere says that it may later incorporate a urea-based system to meet Tier 4 Final, as technology advances.
Caterpillar is building off its ACERT technology by integrating a clean emissions module into more than 300 models with 14 engine platforms. The first engines to incorporate the technology will be the C13, C15, C18, C27 and C32. To accommodate the modules, Caterpillar has been enlarging the engine compartment, which is no small task. The company estimates the investment will exceed $1 billion. Caterpillar says it will recover its losses through an average 12% price increase across all categories of equipment. Ultimately, market conditions will determine how much of that increase Cat can charge.
Case Construction Equipment says it will use both exhaust gas recirculation and selective catalytic reduction selectively. This will address the heightened standards for Caseís 90 models. Case says recirculation cooled exhaust will reduce nitrogen oxides but increase particulate matter, which is why the after-treatment exhaust system will be required.
Most, if not all OEMs, are indicating that power is not affected; the changes may even offer fuel savings. Suchecki says itís just too soon to tell. The new engines are more compatible with ultra-low-sulphur diesel, which will soon be an industry standard. The new fuel, however, may be calling for new engine oils. Catalytic reduction and gas recirculation also impact an engineís running temperatures, which might change oil requirements. Oil-change intervals should not be impacted, Suchecki says.
Many may interpret Tier 4 as just another maintenance burden and cost increase. For others it may be a breath of fresh air. Regardless, Tier 4 is the law. New machines must meet the standards. Older machines will be grandfathered, as supplies last. However, some states are considering mandating retrofits. California already has taken the lead there, and some New England states may be following, Suchecki says.
The standards and timing of European regulations are nearly identical to Tier 4. The final round in 2014 will increase standards even higher, and these after-treatment systems will undergo even more costly optimization. Prices will likely increase further.
This mountain to zero emissions now seems to be an impossible climb, just as impossible as Tier 3 seemed 10 years ago. But when the last tier finally is achieved, the air will be clean and the view spectacular.