July 10, 2015

Forestry Engine Myths and Facts

Emissions, tiers, engines, there are so many different pieces of information flying around regarding performance and maintenance, how do you know what to believe? Below are our responses to some of the most popular myths.

Myth: Newer John Deere engines sacrifice performance and durability to meet emissions regulations.

Fact: Engine performance for Final Tier 4/Stage IV meets or exceeds that of previous John Deere engines.

John Deere PowerTech™ engines continue to provide the same or higher levels of power density and torque along with transient response that meets or exceeds that provided with Tier 3/Stage III A engines. To meet each regulatory tier, John Deere has followed a carefully planned approach. We have systematically adopted new technologies and integrated them with our field-proven base engine platforms. The new after-treatment components associated with exhaust filters and selective catalytic reduction (SCR) are designed to meet the unique needs of off-highway equipment and achieve the same reliability as our proven Tier 3 engines.

Myth: Final Tier 4 engines require more frequent oil change intervals.

Fact: Oil change intervals for John Deere PowerTech™ engines can be extended to 500 hours when the following conditions are met:

  • Use of diesel fuel with sulfur content less than 15 ppm (ULSD diesel fuel mandated by the EPA)
  • Use of John Deere Plus-50™ II or other oils that meet the API CJ4, ACEA E9, and ACEA E6 standards
  • Use of a John Deere engine oil filter

In addition, the initial oil change interval with John Deere Break-In Plus™ oil can occur at 500 hours as well. We recommend using Break-In Plus for a minimum of 100 hours and a maximum of 500 hours to properly break in the engine. Change the oil and oil filter at least once every 12 months even if the hours of operation are fewer than the otherwise recommended service interval.

Myth: John Deere Final Tier 4/Stage IV engines have high internal combustion temperatures.

Fact: John Deere Final Tier 4/Stage IV engines utilizing cooled EGR and SCR actually have cooler internal engine combustion temperatures than previous tiers.

Cooled EGR engines do place more cooling requirements (higher heat rejection) on the cooling system. However, John Deere has adopted new cooling system designs and variable speed fan drives that meet these cooling needs in the most efficient method possible. With the addition of SCR for Final Tier 4/Stage IV, optimized John Deere engine calibrations will utilize lower cooled EGR flow rates than Interim Tier 4/Stage III B, reducing the engine's heat rejection. The optimized John Deere Integrated Emissions Control system approach for Final Tier 4/Stage IV enables cooler engine combustion temperatures. This integrated system of cooled EGR, an exhaust filter, and SCR results in higher power density, higher peak torque values, improved levels of engine durability, lower diesel fuel consumption, and low DEF consumption.

Myth: Engines with exhaust filters require a regular active regeneration during which fuel usage can increase.

Fact: A John Deere exhaust filter typically cleans itself through a process called passive filter cleaning.

Passive cleaning uses heat from the engine exhaust system to continually clean the filter. If conditions (load, speed, and ambient temperature) aren't met for passive filter cleaning to occur, an active filter cleaning is performed and managed by a process called exhaust temperature management (ETM). Other than noticing an icon on the corner post during an active filter cleaning, there should be no impact to the operator. The operator can continue to work with full power available. During an active filter cleaning, a small amount of fuel is dosed into the exhaust system. The exhaust system mixes the fuel with the exhaust gases and routes it to the exhaust filter where it chemically reacts with the diesel oxidation catalyst to aid in filter cleaning. This mixture of fuel is not ignited and there is no flame. It's a simple chemical reaction within the diesel oxidation catalyst.

The most important thing to note is that passive or active filter cleaning does not impact machine operation under most conditions and the amount of fuel used during an active filter cleaning is negligible.

Myth: Machine owners will have to frequently remove ash from their after-treatment systems.

Fact: New John Deere forestry equipment features impressive ash removal intervals.

Accumulated ash will build up over time in the diesel particulate filter (DPF) from the passive and active cleaning process and does require periodic service. Ash service intervals for John Deere DPFs are condition based, meaning the machine will notify the operator before service is required. After millions of hours of real-world use in machines powered by John Deere Interim Tier 4/Stage III B and Final Tier 4/Stage IV engines at or above 175 hp, we've found that ash service is typically not necessary until the first engine overhaul. Actual intervals will be determined by specific machine application and regular maintenance practices, such as the use of lubricating oil formulated to reduce ash. The bottom line? In most cases, ash removal for John Deere DPFs is a very infrequent requirement. The latest models of John Deere forestry equipment are no exception.