Understanding Tier 4 Final

The construction industry is in the heart of Tier 4 final product rollouts. Even low horsepower machines, such as skid steers and compact track loaders, now feature more advanced solutions with acronyms and names that contractors didn’t have to worry about the last time they bought a piece of equipment. Tso complicate matters, many machines now feature combinations of different solutions.

Remember these three words: Don’t be afraid. Buying a new piece of machinery can be intimidating. For many construction companies, these machines are the foundation that will determine whether they discuss profits or losses at the end of the year. This article will break down some of the mystery surrounding Tier 4 technologies and give contractors a better understanding of what it means to their businesses.

The Current Situation

The last of the Tier 4 final regulations went into effect on January 1. Due to government allowances and manufacturer compliance, some original equipment manufacturers are still able to produce Tier 4 interim equipment today with emissions credits. Equipment dealers that have Tier 3 and Tier 4 interim equipment in their inventory are still able to sell it. Owners will not be forced to phase that equipment out—although some jobs and contracts give preference to contractors that have Tier 4 certified equipment. It is important for contractors to understand the Tier 4 needs of their customers before they ever bid on a new job. The following are some of the common terms and acronyms you will see related to Tier 4 as you look at new equipment on the market today.

In-Engine Systems

HPCR: High pressure common rail fuel injection is the first step of many emissions solutions and has been around in equipment for years. Put simply, diesel fuel is injected into the combustion chamber at higher pressures, which allows for a better mixture of diesel and air in the combustion chamber, thus creating a more complete burn of the diesel fuel, which creates less particulate.

CEGR: Cooled exhaust gas re-circulation cools exhaust gas and injects it back into the engine combustion chamber to help reduce nitrogen oxides (NO_X). This was sufficient for Tier 3 emissions standards, but Tier 4 solutions require additional after-treatment solutions, such as SCR, DPFs and DOCs. As a standalone, in-engine system, CEGR requires no maintenance or management outside of normal engine maintenance activities.

After-Treatment Systems

SCR: Selective catalytic reduction is a simple, after-treatment solution that injects diesel exhaust fluid (DEF below) into the exhaust stream and converts emissions into two completely inert substances: nitrogen and water. As an after-treatment solution, SCR helps keep exhaust temperatures lower (compared to those impacted by a diesel particulate filter) and does not require unproductive fuel use associated with burning off particulate matter. This helps lower fuel use, does not require downtime associated with regeneration and only requires that operators remember to top off their DEF tank when they refuel.

DEF: Diesel exhaust fluid is a non-hazardous, scientifically blended mixture of deionized water and urea. Storing and handling DEF is easy, and there are a variety of handling and container options approved for use with DEF. Storing and transferring in unapproved containers or mixing your own DEF is not recommended. As possible, DEF should be stored out of direct sunlight. Optimal storage temperatures are between 12 and 86 degrees Fahrenheit.

DPF: Diesel particulate filters were one of the first after-treatment solutions paired with CEGR. While CEGR helped reduce NO_X emissions, it did not reduce enough of the particulate matter to meet Tier 4 standards. DPFs capture particulate matter and burn it off through a process called regeneration, which can sometimes be done while the machine is operating normally, and occasionally has to be done while the machine sits still, with the engine running at higher temperatures. This can lead to excess burn fuel and some downtime.

Regeneration is the process of burning off all the accumulated particulate matter in the DPF.

DOC: Diesel oxidation catalysts exist both on their own and paired with other technologies, depending on the type and size of machine. In a DOC, the exhaust gas flows through a structure where a catalytic reaction takes place, the exhaust gas is oxidized and water and carbon dioxide is produced. On their own, DOCs are completely maintenance free and require no fluids to add or filters to replace or maintain.

PM Catalyst: A particulate matter catalyst is a combination of a DOC and a high-efficiency, flow-through filter. The DOC oxidizes the machine’s exhaust and the remaining particulate matter then transitions to the flow-through filter, where it is slowed and burned. A particulate matter catalyst requires no fluids to add and no special filters to replace.

Don’t Be Afraid

Using these technologies can be simple; owners and operators only need to spend a few moments reviewing their equipment operator’s manual and familiarize themselves with the systems present and anything they will need to know during operation.

The general consensus of Tier 4 final equipment owners is that the transition has been easy and the learning curve has been minimal. These machines also carry with them the latest in technologies aimed at improving productivity and making the equipment run more efficiently. This helps ensure owners talk more about profits and less about losses when they take stock of their fleet at the end of the year.