What is the John Deere Integrated Emissions Control system?
To meet increasingly stringent emissions regulations, John Deere has followed a "building block" approach in which it has systematically adopted technologies to meet each regulatory Tier. Depending upon the power level and engine platform, the John Deere Integrated Emissions Control system encompasses different combinations of aftertreatment and emissions reduction components. John Deere will continue to tailor its Integrated Emissions Control system configurations to fit a variety of off-highway applications. These tailored configurations will provide an optimized solution that delivers emissions compliance without sacrificing power, performance, fluid efficiency, reliability, durability or economical operating cost.
Why is John Deere implementing selective catalytic reduction (SCR) for Final Tier 4/Stage IV?
Until facing the more stringent NOx emission levels required by Final Tier 4/Stage IV, John Deere has been able to achieve the mandated NOx levels with its cooled exhaust gas recirculation (EGR) technology and a single fluid, diesel fuel. With the additional 80 percent reduction in NOx required for Final Tier 4/Stage IV, John Deere will continue to utilize its proven cooled EGR technology but will combine this with SCR technology to achieve the more stringent Final Tier 4/Stage IV NOx emission levels.
Is John Deere abandoning cooled EGR technology developed for Interim Tier 4/Stage III B?
John Deere will continue to utilize the field-proven cooled EGR technology developed for Tier 3/Stage III A and Interim Tier 4/Stage III B. For Final Tier 4/Stage IV, the optimization of Integrated Emissions Control system components enables a reduction in cooled EGR flow rates, reducing the amount of heat rejection to the engine coolant. The lower cooled EGR flow rates allow an OEM to work with smaller, lower-cost cooling system components and further improve fuel economy.
How is the John Deere SCR solution different from the solutions of other engine manufacturers?
John Deere will use a combination of our proven cooled EGR technology and SCR technology to meet the more stringent Final Tier 4/Stage IV NOx emission regulations. The John Deere solution is different because the combination of the two technologies will allow John Deere engines to utilize less diesel exhaust fluid (DEF) than alternative SCR technology solutions. Less consumption of DEF means DEF tanks can be smaller, impact on equipment applications are minimized, DEF filter service intervals can be extended, and operator involvement is reduced.
Why does John Deere plan to use an exhaust filter (DOC/DPF) for Final Tier 4/Stage IV, while some competitors do not?
Some manufacturers have chosen to calibrate their engines to produce less particulate matter (PM) emissions out of the engine, which reduces or eliminates the need for treating PM downstream of the engine. This approach increases engine combustion temperatures and NOx emissions out of the engine requiring higher levels of diesel exhaust fluid (DEF) to treat the increased NOx downstream of the engine.
John Deere has chosen to utilize cooled EGR and an engine calibration that reduces both engine combustion temperatures and NOx out of the engine. This calibration results in increased PM out of the engine, which is then reduced downstream of the engine with an exhaust filter consisting of a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF).
Our optimized Integrated Emissions Control system components reduce the remaining PM and NOx downstream of the engine. This optimization of our Integrated Emissions Control system components allows the engine to deliver the highest level of engine performance and world class fluid economy while meeting the most stringent emission levels mandated in all regions of the world … today, tomorrow and into the future.
Will exhaust filter regeneration intervals remain the same for Final Tier 4/Stage IV?
John Deere expects to see longer intervals between exhaust filter regenerations with Final Tier 4/Stage IV. In general, the SCR technology and more efficient fuel delivery systems with Final Tier 4/Stage IV engines will reduce PM out of an engine and, as a result, increase the time between any exhaust filter regeneration.
How will engine performance be impacted for Final Tier 4/Stage IV?
Engine performance for Final Tier 4/Stage IV will meet or exceed that of Interim Tier 4/Stage III B engines. John Deere engines will continue to provide the same or higher levels of power density and torque along with transient response that meets or exceeds that provided with Interim Tier 4/Stage III B engines.
How is the durability of the engine impacted by Final Tier 4/Stage IV technologies?
For the most part, base engine platforms will not change with Final Tier 4/Stage IV. As a result, our proven durability will continue from Interim Tier 4/Stage III B to Final Tier 4/Stage IV. The new aftertreatment components associated with SCR and Final Tier 4/Stage IV engines are designed to meet the unique needs of off-highway equipment and achieve the same durability goals as our proven Interim Tier 4/Stage III B engines and exhaust filters.
What is regeneration?
The exhaust filter is integrated into the engine design to provide a simple and reliable solution for reducing particulate matter (PM). A single engine control unit (ECU) manages both the engine and exhaust filter, via an exhaust temperature management (ETM) system, to regenerate (clean) the exhaust filter.
If passive regeneration cannot be achieved due to low temperature, load, or speed, then PM is removed using active regeneration — an automatic cleaning process. In most cases, the regeneration process does not have an impact on machine operation or require operator involvement. Another benefit of the exhaust filter is that it replaces the muffler in most applications.
- Passive regeneration
John Deere engines and exhaust filter components are designed for uninterrupted operation using passive regeneration, a natural cleaning process where engine exhaust temperatures are sufficient enough to oxidize the PM trapped in the exhaust filter. The process occurs during normal engine operating conditions, which is the most fuel-efficient way to clean.
- Active Regeneration
If conditions (temperature, load, or speed) for passive regeneration cannot be achieved, then PM must be removed using active regeneration, an automatic cleaning process. This requires injecting a small quantity of fuel in the exhaust stream for a short duration and elevating exhaust temperatures to clean the filter. Remember, active regeneration cleaning occurs only when passive regeneration is not possible based on temperature, load and speed. It serves as a backup system.
Parked or stationary regeneration may be necessary if active regeneration is overridden by the operator, or in rare instances when the engine does not reach normal operating temperatures because of lighter loads, reduced speeds or cool ambient conditions for extended periods of time.
How does ETM work?
If conditions (ambient temperature, speed, and load) for passive regeneration cannot be achieved, ETM is an automated engine operating mode used to increase the DOC inlet temperature to initiate and maintain an active regeneration. To increase the DOC inlet temperature, ETM may reduce the amount of fresh air entering the engine via an intake air throttle valve, include a later post injection (after main injection event), retard engine timing for the main injection event, or vary the VGT vane position and elevate low idle speed. Once the needed DOC inlet temperature is achieved, a small quantity of fuel is injected into the exhaust stream. This process creates the heat needed to oxidize the PM trapped in the DPF when passive conditions cannot be achieved. In addition, ETM provides an additional benefit of a controlled warm-up and cool-down period, increasing the durability of the exhaust filter.