How exhaust gas recirculation (EGR) works
EGR reduces the high temperatures where nitrogen oxide (NOx) compounds are formed in the engine cylinders by replacing excess oxygen with a prescribed amount of cooled exhaust gas.
Exhaust gases contain more carbon dioxide than oxygen. The EGR valve in conjunction with the venturi and engine control unit (ECU) allows a controlled amount of exhaust gas to enter the intake manifold to mix with the incoming fresh air. Replacing excess oxygen with cooled exhaust gas leads to lower combustion temperatures, creating less NOx. In addition, EGR allows for advanced timing, leading to optimal performance of the engine, maximizing fuel economy.
The following diagrams illustrate how air flows through the engine.
For added performance and efficiency, the engine passes the exhaust gases through an EGR cooler before it enters the engine.
Flow of exhaust during engine operation
Exhaust airflow enters into the EGR cooler from the exhaust manifold near the turbocharger.
Based on engine load, air temperatures, and rpm, the engine control unit (ECU) opens or closes the EGR valve, allowing a measured percentage of exhaust gas to enter the intake manifold.
The gases mix with the rest of the incoming air from the turbocharger and aftercooler before entering the cylinders.
All 8R Series Tractors come standard with an 85-cc displacement integrated hydraulic pump. This pump provides 227.1 L/min (60 gpm) of hydraulic flow.
A dual-pump option, featuring an 85-cc and 35-cc displacement hydraulic pumps, is available for all 8R wheel models. The dual-pump system provides a hydraulic flow of 321 L/min (85-gpm), ideal for running at lower engine speeds.
The maximum flow through one selective control valve (SCV) with a standard coupler is 132 L/min (35 gpm). A ¾-in. high-flow coupler allows for a maximum flow rate out of one SCV of 153 L/min. (42 gpm).
The hydraulic system is a closed-center, power-on-demand system using a load-sensing pressure-flow compensated axial piston pump with full-flow charge and flow prioritization for steering and brakes.
Operating the tractor at reduced engine rpm contributes to a quieter cab, reduced fuel usage, and maintains the vacuum while turning and raising the planter on end rows. At 1500 engine rpm with a 321 L/min (85-gpm) system there will be an available flow of 227 L/min (60 gpm). This is an improvement over an available 153 L/min (42-gpm) flow when operating with a 227-L/min (60-gpm) system at 1500 ERPMs.
The pump outlet pressure available on demand can range from 30 bar (435 psi) for track models and 40 bar (580 psi) for wheel models at low standby to 20,400 kPa (2958 psi) at high standby.
Hydraulic pump options:
The e23 transmission delivers smooth shifting and intuitive controls with Efficiency Manager™ in a reliable 23-speed PowerShift™ transmission. The e23 transmission is available for all 7R, 8R and 8RT Series Tractors.
The e23 has evolved from more than 50 years of John Deere PowerShift technology. With more automatic features, the e23 is easy to operate for all levels of operator experience. For more advanced operators looking to customize the transmission to best fit their operation, the e23 offers a custom mode.
As the next generation of PowerShift technology, e23 delivers the strength to handle sudden, high-torque power loads while maintaining responsive, quick, and smooth shifts. The e23 with Efficiency Manager provides improved fluid efficiency and overall productivity with limited input from the operator.
Even gear spacing for optimal performance
The e23 has 23 forward gears and 11 reverse gears, which are all evenly spaced. Forward gears are spaced apart with a 15 percent speed differential between each gear, while reverse gears are spaced apart with a approximately 30 percent speed differential, providing operators smooth shifting between gears. Even spacing improves efficiency and allows for smooth, automated shifts when using Efficiency Manager. The e23 can reach maximum forward ground speed in gear F20. As a result, gears F21-F23 maintain maximum ground speed at reduced engine rpms to save fuel on 40-km/h (25-mph) transmission.
The e23 is available with either a right-hand or left-hand reverser.
A convenient, right-hand reverser is available with the e23 transmission. The reverser is located on the CommandARM™ controls as shown above.
Right-hand reverser equipped models use four main controls to operate the tractor:
The right-hand reverser control strategy combines speed control and direction control into one multi-function lever that is conveniently located on the CommandARM. This is a good choice for most common field applications since tractor speed and direction are not constantly being adjusted by the operator.
An easy-to-use left-hand reverser is available with the e23 transmission and includes the same functions as the right-hand reverser. The reverser control is located at the 10 o’clock position on the steering column for intuitive control.
The five-position, left-hand reverser column incorporates the following controls:
Left-hand reverser equipped models use five main controls to operate the tractor:
The left-hand reverser control strategy separates the direction control lever from the speed/gear control lever on the CommandARM. This strategy is a good choice for operations requiring the right hand to run multiple operations on the CommandARM or applications requiring constant directional changes like loader work.
Determining which reverser is best suited for a specific operator depends on a few key factors. Consider the following to help choose between a left- or right-hand reverser.
Producers primarily in row-crop applications using features like AutoTrac™ or operating with the seat swiveled to the right for easy access to monitors and displays might find the right-hand reverser more convenient. Speed and directional controls are in one location on the CommandARM.
The CommandCenter is the central information system for tractors and allows the operator to program various settings tailored to a specific operation.
To access the tractor’s transmission settings, press the transmission shortcut button on the CommandCenter shortcut bar.
The e23 application settings employ three modes to take full advantage of the engine-transmission communication: full auto mode, custom mode, and manual mode.
Manual mode operates similar to a traditional PowerShift transmission. When shifting, the transmission shifts gears, not set speeds like auto and custom mode. Manual mode also features Efficiency Manager when the operator engages set speed one or two on the CommandARM, as shown above in illustration.
When operating in manual mode with Efficiency Manager active, there is the option of turning eco on or eco off. This allows the operator to select two different minimum engine speeds. In the advanced settings page, operators can adjust auto shift engine speed droop and load anticipation, similar to custom mode.
Efficiency Manager is automatically enabled in auto and custom mode. Efficiency Manager can be turned on in manual mode by selecting the set speed one or two on the CommandARM. The set speed adjuster on the top of the single-lever gear selector allows the operator to dial in the desired ground speed to establish set speed one or two in Efficiency Manager.
Efficiency Manager allows the transmission to up or down shift and change engine rpm to maintain the set wheel speed. To reach the desired set speed, the throttle must be set to full engine rpm. This allows Efficiency Manager to shift the transmission and adjust engine speed to maintain the desired wheel speed. For more information on Efficiency Manager refer to the operator’s manual.
Both right-hand reverser and left-hand reverser control options provide full powershifts for on-the-go shifting; no need to stop or clutch when bump shifting or shuttle shifting between forward and reverse.
The single-lever shifter allows for quick and convenient shifting with minimal physical effort.
Shifts are made either by bumping the lever or by holding the lever in a forward or rearward position.
A forward gear between 1F and 13F may be preselected by depressing the clutch pedal and pushing or pulling the shift lever. The transmission will then start in the preselected forward gear when clutch pedal is released.
The electrohydraulically controlled brakes on e23-equipped tractors have an integrated AutoClutch function.
Braking can be done on flat ground or steep slopes simply by using the brake pedals; it is not necessary to depress the clutch.
AutoClutch sensitivity can be adjusted through the Generation 4 CommandCenter™. AutoClutch can be deactivated on e23 transmissions as well; however, it will be reactivated after every key start.
During transport, it may be desirable to use the AutoClutch feature to stop the tractor when approaching an intersection or turn. Braking the tractor using the AutoClutch at high ground speed and engine speed will require high brake-pedal force.
Rather than using AutoClutch alone, reduce the engine rpm and reduce the e23 to a slower commanded speed before applying the AutoClutch. This will help to reduce the force needed to stop the tractor with the AutoClutch. The tractor will accelerate to the previously commanded speed upon release of the AutoClutch, repositioning of the hand throttle and increasing the commanded speed.
NOTE: The preferred method of stopping heavy towed loads is to reduce the e23 commanded speed and lower engine rpm first, and then depress both brake pedals. (Brake pedals should be locked together.)
Using individual brake pedals - implement hook-up
Individual brake pedals can be used to assist slow-speed off-road turning, such as hooking up to an implement. At low idle, the AutoClutch feature will stop the tractor if the operator depresses only one brake pedal.
To assist in hooking up an implement, depress either brake pedal while slowly increasing engine speed until the desired turn is achieved. Returning engine speed to a low idle while continuing to depress one brake pedal will slow the tractor to a stop.
Full AUTO mode enables the tractor to make adjustments to the transmission operating mode automatically, based on engine and transmission speed and the load on the tractor. This means the tractor will shift up and throttle back automatically to reach the desired ground speed efficiently. Operators have the ability to set the maximum forward and reverse speeds for the tractor in their particular application.
When shifting in AUTO mode, the transmission shifts set speeds, meaning the transmission may not necessarily shift gears each time the lever is bumped. Efficiency Manager is automatically engaged while operating in AUTO mode. As a result, shifting will not take the tractor out of Efficiency Manager in AUTO mode.
Custom mode allows operators to adjust operating parameters to meet their specific operation. Just like auto mode, custom mode shifts set speeds meaning the transmission may not necessarily shift gears each time the lever is bumped. Efficiency Manager is engaged automatically in custom mode.
In custom mode, eco allows two minimum engine speeds to be set. Operators can turn eco on and off by either pushing the eco button on the side of the throttle or by selecting eco in the transmission settings page of the CommandCenter. For example, operators may choose to turn eco on during transport to utilize a lower minimum engine speed and then turn eco off while operating in the field where a higher minimum engine speed is desired.
In the advanced settings page, operators can customize the auto shift engine speed droop as a percentage of the full engine speed. In addition, the load anticipation feature can be enabled for the hitch engagement, hydraulic engagement, or both.
The cornerpost display shows the commanded gear instantaneously once selected.
When the tractor is working in a light-load condition, for example in transport, the transmission can be shifted rapidly by bumping the shift lever.
To reach transport speeds quickly:
The transmission can skip a gear when operating under load by double bumping the shift lever.
Ground speed matching
When the tractor is slowing down and the clutch pedal is depressed, the transmission will match a gear to the ground speed of the tractor when the clutch is released. Ground speed matching only engages in gears 13F higher.
Setting start-up gears
The 7R Series Tractors default to 9F and 3R at start-up. However, these default start-up gears can be adjusted from 1-13F and 1-6R through the CommandCenter. Refer to the operator’s manual for additional information.
Releasing the park brake
The e23 transmission utilizes a spring-engaged/hydraulically-disengaged park brake. The park brake control feature prevents accidental park brake engagement when tractor is moving at high speed.
On tractors equipped with air brakes, the park brake automatically activates the air brake system.
With ACS, John Deere has designed one of the most robust and full-encompassing steering system in the industry. Whether in the field or on the road, ACS reduces steering effort, which can result in reduced operator fatigue and can improve operator comfort and control.
There are four key features of the ACS system:
Dynamic road wheel offset control:
Variable ratio steering:
Elimination of steering slop and hand wheel drift:
Variable effort steering:
The ACS system is fail operational, which means steering is still functional in the event of any single-point failure. John Deere has gone to great lengths to help ensure the operator has the ability to steer the tractor if something goes wrong in the steering system.
For example, if the primary controller fails, a second controller takes over. If power from the alternator fails, the battery resumes control. If the engine quits running and is unable to supply hydraulic oil to the system, an electric-driven backup pump is used to supply the oil. There is a backup for ACS components.
The ACS system consists of several key components:
The Standard CommandView III cab offers unsurpassed visibility, operator comfort, control placement, and ride and sound quality.
ComfortCommand seat improves ride quality and helps to reduce operator fatigue
John Deere 7R and 8R Series Tractors feature the CommandARM with integrated Generation 4 CommandCenter display. The control layout of the CommandARM utilizes a clean and efficient design which groups controls by function and builds upon John Deere’s history of intuitive and ergonomic control placement and operation. The CommandARM’s design allows for a 40 degree right seat swivel and adjustable positioning matching the operator’s preference.
Controls located on the CommandARM include:
John Deere 7R Series Tractors with CommandQuad transmissions feature a left-hand reverser. 8R Series Tractors equipped with 16-speed PST are equipped with right-hand reverser. 7R Series Tractors equipped with e23 PST offer a left- or right-hand reverser. 7R or 8R Series Tractors equipped with AutoPowr™/IVT are offered with either a left-hand or a right-hand reverser.
The transmission control lever is placed on the CommandARM’s left side closest to the operator for convenient setting and adjustment.
Hydraulic and hitch controls utilize fingertip paddle pods for raise/lower and extend/retract functions. An optional crossgate joystick replaces fingertip paddle pods for control of SCVs and allows for programmable hydraulic functionality according to operator preference. Rear hitch position can also be controlled with the encoder wheel located on the right side of the CommandARM. The encoder wheel allows for finite positioning of the rear 3-point hitch.
Three buttons near the encoder are for hitch set, lock, and return to height. Adjustment knobs for the 3-point hitch are located under the cover for the CommandARM’s storage compartment and allow for adjustment of the rate of drop, hitch height limit, and depth control.
The throttle design incorporates buttons which control FieldCruise speed, foot pedal mode (if equipped), and transmission eco settings.
Tractor function controls
Located just to the right of the throttle is the Auto-Trac-activation button and four sequence controls for iTEC functions. Behind the iTEC sequence controls there are buttons which control the activation and deactivation of MFWD and differential lock. Differential lock can also be activated by the foot switch on the cab floor.
Controls for radio, lights, rotary beacon (if equipped), hazard flashers, and HVAC system are located to the center-right on the CommandARM, along with PTO for both front (if equipped) and rear PTO.
The design of the CommandARM allows for up to 40 degrees of right-hand seat swivel.
The Generation 4 CommandCenters feature fast adjustment of tractor functions and controls and are integrated into the CommandARM to create a seamless control center. The 4100 CommandCenter features a 178-mm (7-in.) touchscreen display and is standard equipment on 7210R and 7230R models, while the 4600 CommandCenter features a 154-mm (10-in.) touchscreen and is standard equipment on 7250R – 7290R models, as well as all 8R and 8RT models.
The following functions can be adjusted using the CommandCenter display:
The 7R, 8R, and 8RT Series Tractors feature two lighting package options:
The cab lighting pattern provides 330 degrees of coverage while the hood lighting provides the remaining 30 degrees, for completely-programmable, 360-degree, stadium-style lighting. This ensures there are no dead zones or lighting adjustments needed. The lighting configurations are available to match various applications and ensure maximum around-the-clock productivity.
Bulb housings are large, allowing for optimum total lumens and available light. The economy and standard lighting packages use 65-W halogen bulbs, whereas the premium lighting package uses light emitting diode (LED) lights. In the premium lighting package, these tractors take advantage of the high performing and efficient LED technology.
The low and high beam driving/work lights are adjustable. Please refer to the operator’s manual section Electrical Services for complete details on adjusting lights.
Adjustable high-beam driving light/work light
License plate bracket with light
Adjustable low- beam driving light/work light
Fixed amber light
Adjustable halogen light
Adjustable mid-body halogen light
Fixed high-intensity discharge (HID) light
Adjustable HID light
Mid- body hazard, turn and width indicating light
Amber turn and brake light
Six front grill-mounted lights:
Ten cab roof-mounted lights:
Plus these lights:
Eight front grill-mounted lights:
Twelve cab roof-mounted lights:
The premium lighting package replaces all previous halogen and high-intensity discharge (HID) lights with LED lights. The only lights that are not LED are the low beam driving lights, they remain halogen. This allows each LED light to work at a lower temperature and no one light works harder than any other. The uniformity in LED coverage allows only one type of light output surrounding the tractor.
The lighting pattern in the premium package provides industry-leading performance in nighttime visibility. LED bulbs provide maximum brightness and a true color output for excellent field definition that is easy on the operator's eyes.
The LED lights provide 40 percent greater coverage width and 10 percent more rear light coverage. LED lighting packages use 45 percent fewer amps than standard halogen lights and have an increased life expectancy over HID lights which leads to lower costs of ownership over the life of the tractor.
NOTE: Lighting packages may vary depending on region.
Field-installed options are also available. To find this information, use the Build Your Own Configurator application.
Operators can quickly select a lighting mode on the steering console:
The battery power-saver feature is also standard. When the engine is off and the outside lights have been left on, this feature is designed to avoid battery run-down.
After the lights have been left on for 30 minutes and the key is in the off position, the lights cycle or blink on and off five times as an alert. The lights continue to illuminate for one more minute and then automatically shut off to protect the battery.
Another feature is programmable exit lighting. Exit lighting allows the lights outside the cab to stay on for up to 300 seconds. They can be programmed in increments from 0 to 300 seconds.
Refer to the operator’s manual for complete instructions on programming field, driving and exit lighting.
The CommandCenter™ console allows operators to customize light settings. Operators can select only the lights they need or want for a given application and store these settings. The operator-programmed configurations can then be turned on or off with the push of a button on the CommandARM™ controls.
NOTE: Road/loader lights are also referred to as high-mounted driving lights for use in front hitch applications that obscure the headlights. See the Attachments section.
The brakes are designed with large-diameter rear disc brakes and powerful activating pistons. The brakes run in oil for cooling and long life in the most demanding situations. Braking in the field during a turn can be accomplished with light pedal effort and excellent modulation of brake forces.
Hydraulically actuated, power wet-disc brakes:
An integrated park brake is included with all transmission options.
Front wet-disc brakes are included on 7R Series Tractors equipped with a
50-km/h (31-mph) Triple-Link Suspension (TLS™) Plus front axle.
Foot brakes on tractors equipped with AutoPowr™ transmission/Infinitely Variable Transmission (IVT™) have an integrated automatic clutch function, as described in the IVT section.
For towing very large loads, the 7R Series Tractors can be equipped with a complete air-brake-system or a hydraulic brake coupler, or both. The brakes supply air or oil pressure to a brake-equipped trailer or implement.