Air fresheners: the onus to meet EPA diesel engine emission standards is on equipment manufacturers.

Environmental regulators are very interested in off-road engines and equipment, including machines used in the recycling industry. For engine manufacturers, regulations have increased machine complexity. More emphasis is being placed on maintenance and after-treatment strategies. Retrofitting existing fleets to clean up their emissions, especially in areas designated as non-attainment zones for air quality by the Environmental Protection Agency, is also likely to grow.

Here's the good news for recycling companies In the United States, the burden of meeting emission standards is squarely on the shoulders of the engine manufacturer. (Canadian regulations are mirroring U.S. laws.) In other words, scrap handlers and other equipment buyers are not responsible for meeting emissions regulations. When recyclers buy new equipment, it will automatically meet the emissions standards in place at the time the units were manufactured. However, state and local regulatory bodies may offer incentives, such as access to jobs or higher payments, for complies using the cleanest machines.

Fault codes should be heeded and repairs made as soon as possible to ensure engines operate as the manufacturer intends. Equipment owners also are strongly encouraged to keep accurate maintenance records in case of an inspection.

BACKGROUND. Clean-air legislation has been around for years. Prior to 1955, cities, counties and states all carried air-quality laws on the books. The Air Pollution Control Act of 1955 turned air-quality regulation into a federal matter. In the 1960s, U.S. regulations established standards for automobile emissions.

The basis for today's rules and regulations is the Clean Air Act of 1990. The first tier of emission regulations for off-road diesel engines arrived in 1994. Subsequent tiers define increasingly tighter emissions requirements for these engines.

Internal combustion engines produce four major emissions: nitrogen oxides (NOx), particulate matter (PM), hydrocarbons and carbon monoxide. For diesel engines, the regulatory focus is on NOx and PM.

Both the U.S. Environmental Protection Agency and the European Union (EU) implemented two separate standards--one for on-highway truck engines, another for off-road use--regulating emissions.

The off-road standards are being phased in over a number of years, gradually reducing the legal levels of emissions for various sizes of diesel engines. In the United States, these phases are identified as "Tiers" (Tier 1-Tier 4). In the EU, they are identified as "Stages" (Stage I-Stage IIIB). In time, the differences between on-highway and off-road standards will narrow, and the two sets of standards will converge.

The EPA estimates that by 2010, Tier 3 standards will reduce NOx emissions from diesel engines by about 1 million tons per year, an effect similar to taking 35 million passenger cars off the road.

Tier 4 standards are even more stringent, reducing NOx emissions by 90 percent beyond Tier 3 regulations.

Manufacturers met Tier 1 levels through relatively minor engine modifications, including changes in fuel rates, timing and compression. Air-to-air aftercoolers and turbos made Tier 2 engines visually distinct from earlier engines. But Tier 3 requirements forced manufacturers to take a big leap in engine development. That was when Caterpillar introduced engines with ACERT technology.

The core concept behind ACERT technology is advanced combustion. The combustion process is carefully controlled to reduce pollutant levels, while maintaining performance and efficiency.

Other companies introduced engines with various forms of exhaust gas recirculation (EGR), a process that returns exhaust gases to the combustion chamber.

To meet Tier 4 requirements, Caterpillar is focused on deep machine integration, electronic controls and aftertreatment. Other manufacturers will also need to make changes to reach Tier 4 goals.

VARIED REGULATIONS. Emissions regulations vary throughout the world, which introduces a layer of complexity to moving machines across borders. Certification labels must be attached to diesel engines before they are allowed into the United States. Customs officials inspect off-road equipment at the port of entry and will not allow machines without labels that correspond to the tier level in place at time of manufacture. These labels must remain on the engine and they must be easily visible in case of inspection. These labels must also be in place in order for a piece of equipment to be resold.

That means recyclers won't be able to import new machines originally sold outside the United States without an EPA label. They will, however, be able to import used machines that do have the label.

NON-ATTAINMENT ZONES: The EPA has designated more than 470 counties as non-attainment areas in the United States. A non-attainment area is identified as a location where air pollution levels persistently have exceeded national air quality standards established by the Clean Air Act. State and local governments that used to set their own standards are now planning to meet the federal standards.

Diesel engines have been retrofitted to meet Tier 2 requirements in on-highway and off-road applications. Cat dealers, for instance, have installed diesel oxidation catalysts on buses and catalyzed converter mufflers on landfill tractors. Other retrofit solutions can even include installing new engines in existing machines. In some instances federal assistance has been used to retrofit older diesel engines.

With equipment manufacturers bearing the responsibility for complying with air emissions regulations for off-road equipment and on-highway vehicles, recyclers can concern themselves with the task at hand: efficiently processing and handling material.

LESS PAIN AT THE PUMP

For recycling businesses that run their own on-highway truck fleets, recent fuel tests comparing a Caterpillar engine to a competitive engine with cooled-EGR shows the Cat engines can deliver more than 5 percent better fuel economy, according to the company.

In late 2005, a fuel test conducted by an independent consultant found that the Cat C15 engine achieved 5.8 percent better fuel economy than the Cummins ISX, according to a press release from Caterpillar.

The two-day test run from Denver to San An tonic, Texas, compared vehicles specified to manufacturers' recommendations pulling identical 53-foot air-ride dry van trailers loaded to 79,000 GVW, driving at posted speed limits. The Cat O15 was a 435-hp, multi-torque engine with 1,550-1,750 pounds per foot of torque. The comparable Cummins ISX had a 450-hp engine with 1,650 pounds per foot of torque.

A second test also was conducted, this time using SAE Type III (J1526) test standards. The results showed a 3.2 percent fuel economy advantage for the C15 as compared to the Cummins ISX, according to Caterpillar.

CAT DEBUTS 4.4-LITER DIESEL ENGINE

Caterpillar has introduced a new 4.4-liter diesel engine available with either an electronic fuel management system and ACERT Technology or a mechanical fuel management system without ACERT Technology. Both versions meet Tier 3/Stage IIIA emission regulations.

With output from 83 to 142 hp at 2,200 and 2,400 rpm, the new C4.4 engine with electronic fuel management is the smallest offered by Caterpillar using ACERT Technology. 04.4 engines with ACERT Technology and electronic fuel management systems feature four valve heads and a choice of single or multiple vee-belt front-end drives. Either turbocharged or air-to-air aftercooled configurations are available.

C4.4 engines with mechanical fuel management systems feature two valve heads, a rotary fuel injection pump, a single vee-belt design and optimized inlet manifold temperatures when operating above 100 bhp (75 bkW). These mechanical engines are available in naturally aspirated, turbocharged and air-to-air aftercooled configurations.

More information on the 4.4-liter engines is available at www.cat.com.

This article was submitted on behalf of Caterpillar Inc., Peoria, Ill.