Engine, PowerTech Plus™ 9.0 L - what is exhaust gas recirculation?
PowerTech Plus 9.0 L, 4 valves per cylinder

PowerTech Plus 9.0 L, 4 valves per cylinder

Emission information


The 1990 Clean Air Act passed by the U.S. Congress gave the Environmental Protection Agency the authority to regulate non-road diesel engine emissions. The EPA's first step to reducing non-road emissions was known as Tier 1, and its primary goal was to  reduce oxides of nitrogen (NOx). Tier 1 and Tier 2 were progressively implemented with 8010 and 8020 Series tractors, without major impact on tractor performance.  Tier 3 is the next level of regulation, which has progressively stringent requirements for (NOx).  This regulation becomes effective 1 January 2006.


The 8030 Series 9.0 L (548 cu. in.) engine is EPA-certified for Tier 3 emission requirements.  The method John Deere has chosen to meet these requirements uses cooled EGR (Exhaust Gas Recirculation).  EGR is a proven technology used on heavy-duty highway truck engines.  John Deere has taken that technology and developed it specifically for the off-highway 9.0 L design.  The overall result is performance and efficiency that are unmatched.

How exhaust gas recirculation (EGR) works

Tier 3 emission regulations require a reduction in oxides of nitrogen (NOx) coming from the exhaust.  NOx is formed by high combustion temperatures in the cylinders created as the fuel is burned.  EGR reduces the high temperatures where these compounds are formed in the engine cylinders.  The EGR valve allows a controlled amount of exhaust gases to return into the running engine.  The exhaust gasses have less oxygen and more carbon dioxide than the rest of the incoming air.  Fuel burning in the engine with slightly less oxygen and more carbon dioxide in the combustion chamber leads to lower combustion temperature, creating less NOx emissions.  The diagram below signifies how the air flows into the engine.


For excellent performance and efficiency, John Deere cools the exhaust gases before entering the engine.  Cooling also leads to lower combustion temperatures and less NOx emissions.
Flow of exhaust during engine operation  
Exhaust airflow enters into the EGR cooler from the exhaust manifold near the turbocharger.
Cooler takes hot exhaust gases and cools them to where the temperature will not have excessive impact on combustion efficiency.
Based on load, air temperatures and rpm, the engine control unit opens (or closes) the EGR valve, allowing exhaust gases into the intake manifold.  The gases mix with the rest of the incoming air from the turbocharger and aftercooler.
Base Equipment On : 8030 Series Tractors
Last Updated : 24-Jul-2013