Tier 4 Emissions – What’s it all about?

What is Tier 4?

EPA established a set of emissions requirements referred to as Tier 4. These requirements have been implemented to reduce the emission of oxides of nitrogen (NOx), particulate matter (PM), and other toxins into the air. In order to assist in the steady rate of air quality improvement, EPA put forth the New Source Performance Standards (NSPS), which is an emissions regulation in large stationary generator sets. Tier 4 emissions requirements only apply to new products and not to existing machines or equipment.

What is the difference between Tier 4i and Tier 4F?

 January 1, 2011, NSPS emission standards were referred to as Tier 4i, or interim. The standards of Tier 4i significantly cut NOx emissions and expanded on operational flexibility.

In 2015 Tier 4F, or final was set into play as the emission standard on all large stationary generator sets. This standard requires a large reduction in particulate matter as well as presenting the highest level of clean air regulations.

Do the Tier 4 engines require different fuel?

The new generation of Tier 4 engines do require different fuel. They require the use of an ultra-low sulfur diesel fuel (ULSD). This unique fuel has been being used since 2006 in highway vehicles. Both higher sulfur diesel fuel and the machines that require it have been diminishing in quantity since 2010 to assist with the clean air act.

Why are these changes being made?

 Over years of factories, cars and other machinery running on toxic fuels, the air has become filled with chemicals that cause cancer, asthma and other health-related problems as well as effecting our ozone and animals. Through the Clean Air Act, EPA is working to set national standards on the levels of emissions. Each state that have levels of emissions exceeding the standards are working to develop a plan to improve the air quality starting with new cleaner diesel engines.

How are the Tier 4 engines different?

 These new Tier 4 engines are all going to be different depending on the manufacturer, however; there will be some common factors across the board. More of the Tier 4 engines are controlled electronically where the computer is monitoring and adjusting the fuel and air mixtures. These new engines are also equipped with new systems to work with the increase in heat rejection.

Two main technology pathways to replace the old mufflers and exhaust systems are exhaust gas recirculation (ECR) and selective catalytic reduction (SCR). The ECR works by recirculating some of the used gases back into the combustion chamber. This works to lower the combustion temp and reduces NOx from forming. One of the larges changes in the machines is the use of SCR. In earlier years this was seen in large trucks in Europe and it has been implemented into the new Tier 4 machines. SCR is a process in which a mist of chemicals called diesel exhaust fluid (DEF) is sprayed to react with the exhaust nitrogen oxides and lower tailpipe emissions. The chemical spray and misting system is worked into the controls of the engine to work automatically.

These are a few of the difference that are seen in the new Tier 4 engines. There other differences and depending on the manufacturer there may be even more changes, but with these strict guidelines of Tier 4, generators and other engines will work to help with the clean air act and improving the air quality for future generations.

Here at Woodstock Power, we work to provide the best used generators available. We have Tier 4 generators available for purchase. If you have any additional questions about Tier 4 engines or can’t fine what your are looking for in our inventory please contact us at sales@woodstockpower.com or calls us at 610-658-3242. We are always available to help you find what you need.