10 Myths about Tier 4

The implementation of Tier 4 regulations is well under way, impacting construction fleets across the country. Yet, many in the industry remain unsure of the exact implications of these standards. Listed below are the 10 most common Tier 4 myths and the truth behind these misconceptions.

Myth 1: SCR technology is relatively unknown.

Fact: Selective catalytic reduction (SCR), an exhaust system with a maintenance-free catalyst, has been used by manufacturers of on-highway certified engines for the North American market since 2010. A common technology used on utility and industrial boilers, SCR was invented in the late 1950s, and its first large-scale installation occurred in the late 1970s. The systems have been well-accepted by the buyers and operators of commercial trucks and buses. SCR systems also are used on all automotive and light-truck diesels sold to the North American market.

Myth 2: DEF is daunting.

Fact: Diesel exhaust fluid (DEF) is mostly water. To be exact, it consists of 67 percent water and 33 percent liquid urea, a chemical related to ammonia. DEF is nontoxic, unlike the motor oil, hydraulic oil, diesel fuel and gasoline we use every day. DEF is clear and looks just like water. It also has a viscosity similar to water, making it as thin as water at room temperature. 

DEF freezes at 12 degrees Fahrenheit (-11 degrees Celsius), well below the freezing point of water (32 degrees Fahrenheit, 0 degrees Celsius) and also below the gel point of No. 2 diesel (17.5 degrees Fahrenheit, -8 degrees Celsius). 

DEF also is readily available; package quantities of 1 and 2.5 gallons are available at equipment dealers, auto parts stores and almost all fuel stations. Bulk containers are available from oil distributors, and many truck stops have installed dispensing pumps near fueling islands.

Myth 3: All diesel engines will have DPFs.

Fact: Not all Tier 4 diesel engines will have diesel particulate filters (DPFs). Select engine manufacturers have invested heavily in research and development and have a thorough understanding of customer applications. This has resulted in some Tier 4 diesel engines that do not require DPFs.

Myth 4: Heat rejection will nearly double.

Fact: Because of the engineering efforts of engine manufacturers, engine timing can be advanced, exhaust gas recirculation (EGR) usage is minimal, engine-out particulates are low, and NOx can be treated with an SCR catalyst. The result is heat rejection levels that aren’t much more than Tier 3 engines.

Myth 5: Exhaust aftertreatment will be unmanageable.

Fact: As with most things in life, an open mind, a positive attitude and help from friends can minimize seemingly big problems. Your engine supplier will have the information and varying exhaust aftertreatment packages to help the manufacturer implement a solution that will be easy to maintain and service.

Myth 6: Fuel economy will suffer.

Fact: An SCR system allows for treatment of some NOx exhaust after it has left the engine and before it is released into the environment. This process allows engineers to adjust engine timing and other parameters so that the engine runs cooler and burns less fuel. Engine manufacturers that have spent the most time engineering their systems up-front are able to design and build the most economical engines. Customers will make the best purchasing decisions when they understand that they are paying for both the physical material and the engineering development that ensures high performance in addition to low maintenance and repairs.

Myth 7: Engines will not last as long as they once did.

Fact: With advances in materials, new engineering techniques and additional research and development, engine manufacturers have created Tier 4 diesel engine offerings that operate at cooler internal temperatures and use the latest in high-pressure fuel injection technology. The cleanliness of an engine’s exhaust indicates the cleanliness of the combustion in the cylinders. 

Clean combustion results in a cleaner engine internally, which will produce less wear. This means fewer wear particles will be handled by the engine oil, and fewer wear particles means less damage. Clean combustion also reduces the amount of soot and combustion byproducts that contaminate or degrade the oil. All of these factors help to increase the time before overhaul compared with earlier generation engines. These factors also reduce the cost and frequency of maintenance intervals.

Myth 8: I have to tell my customers that my Tier 4-compliant machines can no longer be exported to less-regulated regions.

Fact: Many engine manufacturers offer kits that can be applied to used engines to make them tolerant to the operating conditions and higher-sulfur fuels in other areas of the world. This enables machines with Tier 4 engines to be second-sold to areas that do not yet require Tier 4-compliant engines.

Myth 9: Cold weather engine operation will become more difficult.

Fact: There is no requirement to maintain exhaust heat for DPF regeneration in Tier 4 engines that do not use these filters. Such engines use only SCR catalysts, which require less exhaust heat to function properly. Because the function of the SCR catalyst is to reduce NOx in the exhaust and most NOx is created at high combustion temperatures (e.g. when the engine is working hard), machines generally have no difficulty generating heat for this catalyst when it is needed. 

To improve cold starts, many manufacturers are testing and approving grades of oil that allow fast cranking of cold engines. Some manufacturers also are working on fuel injection and combustion systems that will result in unaided cold starts at temperatures as low as -22 degrees Fahrenheit (-30 degrees Celsius), which, to some, seemed impossible 10 years ago.

Myth 10: More engine maintenance will be required.

Fact: Engine manufacturers have completed extensive development in order to meet lower exhaust emissions and to achieve cleaner engines that require less maintenance. These improvements are the result of feedback from customers who asked for longer maintenance intervals. When selecting a supplier, look for a company that is focused on the design and manufacture of Tier 4 engines to ensure you take advantage of these new technological developments.