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  • Tier4 Engine Ultimate goal:Make Exhaust Gas as Clean as the Air We Breathe.

Tier 4: Unknown Territory for Global Engineers

Since creating the world’s first practical compact diesel engine, Yanmar has been at the forefront of the evolution of diesel engines. Environmental performance is no exception.
Commencing in 2013, Tier 4 (19 ≦ kW < 56) is the fourth stage of emissions standards set by the U.S. EPA (Environmental Protection Agency). Compared to stage 3 it was a significant regulatory tightening, being referred to amongst some in the field as requiring emissions to be "cleaner than the air we breathe". The only way for engineers to succeed in meeting Tier 4 standards was an unhesitating willingness to venture into unchartered territory.

NOX (nitrogen oxides) + NMHC (non-methane hydrocarbons)

PM (Particulate Matter)

Tier 4 greatly strengthened regulatory values (19 ≦ kW < 56)

First Across the Line to Clear the World's Highest Hurdle

Since diesel engines burn fuel for power, it is not possible to achieve zero emissions. As a company we accepted the challenge, to bring exhaust emissions down to Tier 4 compliant levels while providing reassurance for our customers.
With previous diesel engines, the focus was on the mechanical work done by the engine. However, the most important characteristic of our Tier 4 compliant engines are the electronic control systems. Electronic control has been closely integrated into the engine and the difference is much greater than it first appears. To produce this engine, both the design and the production method of the engine had to be altered. It is no exaggeration to say we created a new diesel engine: a diesel engine for the future.
The diesel engine of tomorrow is in the making today. These innovations aren't limited to the engine's electronic control unit and R&D, but extend to other areas as well, such as a complete revamp of the production lines that make the engines.

The road to success isn't always straight forward, but our Fundamental Principle of "to conserve fuel is to serve mankind" provided a compass to keep us moving in the right direction. Combining innovative technology and determination as a diesel engine maker, Yanmar's was the first engine to be certified by CARB (California Air Resources Board) for full compliance of Tier 4 standards.
This was followed by U.S. EPA Tier 4 certification, and now the engine is receiving high praise from customers all over the world.