Hybrid Electric Drive System on the 944K

What it is

The revolutionary hybrid-electric drivetrain consists of the John Deere 13.5L engine, gearbox, two 3 phase Alternating Current (AC) permanent magnet generators, power electronics or inverters, four 3 phase Alternating Current (AC) Switched Reluctance (SR) motors, four 2 stage reduction final drives, and two brake resistors. The electric drive components are backed by an 8-year, 20,000 hour warranty providing peace of mind when investing in this machine.

How it works

• The John Deere 13.5L engine which operates at either a limited engine speed range or at constant speed, like a generator set, connects to a gearbox which houses the hydraulic pumps.
• The gearbox then transfers engine power to the electric generators and hydraulic pumps.
• The electric generators convert rotational energy from the engine into 3-phase alternating current electrical energy.
• From here the power electronics, or inverter, delivers this electrical energy from the generators to the electric motors based on operator demand.
• The electrical motors convert the 3-phase alternating current back to rotational energy and torque into the final drives.
• Excess energy is passively consumed through two brake resistors that assist in maintaining reversal performance and engine over speed while coasting downhill.

Why it matters

• Engines that can be run at constant speed like a generator set typically have very long life when operating over a limited speed range.
• When the operator lays off the accelerator pedal, changes direction, or when the loader is driven downhill, inertia and gravity can continue to drive the loader. When this happens, the electric motors are being mechanically driven by the wheels through the driveline and temporarily become generators, adding supplemental energy to the electric drive system.
• This recovered energy is sent to the power electronics which can in turn now use this energy to assist the hydraulics system, reducing the load on the engine and allows the engine controller to send less fuel to the engine which is where the gains in fuel economy become very evident.
• The power electronics is able to constantly monitor all the energy in the system and helps determine the most efficient path for this energy to go. Additionally, it will not send power to the wheels that are in the air, increasing overall efficiency.
• Recycled energy cannot be stored long term by the electric drive system but there is a system in place that allows the excess energy to be consumed in the form of the two brake resistors that consume extra energy and assist in braking limiting the amount of mechanical braking needed which in turn reduces brake wear and lowers maintenance costs. The capacitance in the system allows for short term bus voltage draw up which can be very impactful in V-pattern loading, leading to fuel consumption reductions.

944K Wheel Loader Hybrid-Electric Drive Warranty

Enjoy peace of mind with a standard, limited, or basic warranty on specific 944K electric drive generators, brake resistors, wheel motors, and inverters for 8 years or 20,000 hours, whichever comes first.*

*Through July 31, 2022. Components must be rotated between 15,000 and 18,000 hours. Drive voltage cables are not covered and must be replaced between 15,000 and 18,000 hours. Annual machine inspection must be performed by an authorized John Deere Construction and Forestry dealer.

944K Hybrid

The 944K is the most fuel-efficient machine in its size class meaning that it can move more material while burning less fuel.  This allows operations to put more material through the crusher while burning less fuel.  In addition, it’s design efficiencies help realize additional environmental impact reductions through common tasks on aggregates jobsites helping to lower carbon emissions and reducing the 944K’s overall environmental impact.

• The 944K burns 13-33 percent less fuel over conventional drive loaders in V-pattern truck loading and load and carry applications that are common on aggregates sites. This translates in up to 31 kgs less of CO2 being emitted per hour compared to a traditional drive machine within this size class translating into 930,000 kgs less of C02 emitted over 30,000 hours.
• The hybrid electric drivetrain on the 944K helps prevent excessive tire spin resulting in increased tire life meaning the 944K will require four less tire changes over its life, preventing over 90,000 kg of CO2 from entering the atmosphere that would have occurred through the cost of manufacturing and disposing of the extra tires.
• Lower volumes of oil and fluids are required when performing recommended preventative maintenance translating into 11,000 kg of CO2 less over the life of the machine when compared to a traditional drive loader.
• There is a 6 percent reduction in global warming potential impact related to manufacturing when the machine undergoes a MidLife or ReLife.
 

CO2 emission equivalency table

944K in a rock quarry

The 944K comes with exclusive and customizable features that ensure maximum productivity occurs while also reducing fuel consumption and tire slippage, which are major drivers in a machine's operating costs.

Exclusive hybrid electric features

• Traction Control is a standard and exclusive feature to the hybrid electric drive system that automatically limits torque to any wheel when slippage occurs, eliminating runaway wheel spin and increasing tire life.  Traction control aggressiveness can be set by the operator but the feature itself is automatic and requires no operator input during machine operation.
• Coast Control is another standard and exclusive feature on the 944K that gives the operator the capability to adjust the aggressiveness of the machine during deceleration through the use of dynamic braking. This feature extends the life of the service brakes and has three adjustable settings to adjust to any operations productivity needs.
• The efficiency of the electric drive system allows the 944K to realize strong pushing power and quick ramp climbing abilities, making it easier to operate and increasing operator comfort when going into rock piles and ramp climbing between benches at a quarry.

Additional benefits

• Rimpull Control limits torque to the wheels on the ground when in soft or slippery conditions to avoid tire spin and slicing.  It also optimizes traction when crowding against a load.  Rimpull control settings are selected on the SSM through four increments, that decrease the amount of torque to the wheels
• Auto Idle can be set to automatically lower engine speed when the machine is not in motion and no functions are being activated and Auto Shutdown shuts the machine down after a period of inactivity to help lower fuel costs and save machine warranty hours.
• The electronic displacement control, high efficiency, flow-sharing hydraulic system produces the fastest cycle times in its size class increasing productivity. The boom and bucket functions each have their own hydraulic pump which provide quick response and fast smooth hydraulic operation allowing the operator to load trucks faster.

Normal vs. performance engine speed modes

• Normal or Variable Speed Mode runs the engine at maximum speed 1200, 1650, or 1800 RPM depending on operator preference.
• Performance Mode runs the engine at a constant engine speed of 1200, 1650, or 1800 rpm and was designed for customers who are used to running competitive machines with throttle lock.  Desired RPM can be selected by pressing the engine rpm increase and decrease button on the SSM. 
• In certain applications, running normal mode up to 1650 RPM can match productivity capabilities of a machine running in performance mode at 1800 RPM while burning significantly less fuel.

944K undergoing a MidLife

Loaders in this size class are expected to last multiple lives and total cost of ownership is a key factor in upfront purchasing decisions.  Since the 944K does not contain major components like axles and a transmission, those components will not need to be rebuilt or replaced like a conventional drive loader. Because of this, a MidLife event between the 15-18k hour range costs approximately 50-60 percent of the cost of rebuilding a traditional drive machine.

• The electric wheel motors and final drives are designed to last in excess of 30k hours. Wheel motors simply need rotated and inspected during MidLife and ReLife events. This ensures that wear can be evenly distributed to maximize component life and eliminates costly repairs like the rebuilding or replacing of axles.
• All of the electric components on the 944K were designed to last the life of the machine and most only require an inspection during a MidLife event helping decrease the amount of labor during the process.
• Replacing electric cables and rebuilding or replacing the engine are the only major component repair or replacement tasks required during a MidLife event helping significantly drive down costs.
• John Deere Certified Rebuild Centers contain the expertise, tools, and facilities needed to accommodate midlife's and relife's on the 944K in an efficient manner.

View of dual tilt cylinders and front floor to glass windows from operator’s seat

Deluxe lighting package on a 944k working underground

Maintaining visibility to your surroundings is crucial in applications that the 944K is utilized in. With that in mind, John Deere has designed the machine to allow optimum operator line of sight to key components like the bucket and tires while also offering additional features that enhance visibility around the entire machine. The 944K cab is the largest in the Deere loader lineup and provides functions that enable overall ease of operation.

• Dual tilt bucket cylinders provide best in class visibility to the center spade tip of the bucket which is beneficial in truck or hopper loading applications so that the operator can avoid damaging the truck or plant.
• Ceiling to floor glass design on the front windows allows the operator unparalleled line of sight from the seat to the tires to determine if they are spinning and to also provide better awareness of hazards like sharp rocks that could damage the tires. Filleted front fenders also provide operator better visibility compared to the competition.
• The three lighting package options available on the 944K ensure the machine is well lit during times of low sunlight or if it is operating underground enabling increased visibility to the operators. surroundings. The addition of LED’s ensures that lights will last nearly the life of the machine resulting in less downtime and an increase in light emitting power.
• Rear Camera with Rear Object Detection System adds a high-definition color camera mounted on the rear of the machine that displays on the monitor for viewing behind the machine. The radar system detects objects behind the machine through audible chirps that increase in intensity when the object gets closer to the machine.
• Due to the design of the hybrid electric system, features like coast control enable operators to often times control movement and stopping of the machine using just one pedal. When operating the 944K in performance mode there is continuous flow within the hydraulics system enabling on demand hydraulics that assist in multitasking especially when bringing the machine to a stop and raising the boom and bucket to load trucks or processing plant.

Right side service access

Access to the cooling package on the 944K

The 944K offers the lowest preventative maintenance cost per hour in it’s size class over traditional drive loaders and is designed with ease of serviceability in mind through both ground level and left and right side lighted platform access.  It also comes with the Quad-Cool™ Cooling System, a John Deere exclusive, that places the radiator, air-conditioner condenser, intercooler, and charge air, hydraulic, fuel, gearbox, power electronics and axle coolers in a unique boxed configuration that is isolated from engine heat to more efficiently cool these components throughout the day.

Serviceability Benefits

• The 944K has a 10% preventative maintenance cost advantage over traditional drive loaders due to less oil and other fluids that are required to be changed out on a regular basis resulting in a $0.37 cost per hour advantage.
• Left and Right-side engine compartment doors are easy to access through a bottom panel that swings down for greater access where you will find common maintenance items like filters, fluid checks and fills, sampling and diagnostic test ports, and DOC/DPF.
• The machine platform is accessible on both the left and right side of the machine and dedicated platform lights allow easy viewing during low light conditions.
• The two-stage air cleaner that is accessible through left side engine compartment door is a rotary ejector pre-cleaner that filters out large particles to minimize premature air filter plugging to increase machine uptime and contains a sensor that can monitor if there are flow restrictions.
• The Fuel and DEF fill are located on the back left side of the machine and can be easily filled from the ground level.
• Optional auto lube system is hydraulically driven ensuring that grease is automatically delivered to critical machine joints throughout the day, helping prevent pin and busing wear.

Quad Cool Benefits

• The coolers are arranged in a manner that the operator has wide open access to both sides of them ensuring that all debris collected in the coolers can be cleaned out.
• Cool-on-demand hydraulically driven variable speed fan is included with the speed of the fan being determined by the machine fluid temperatures resulting in better fuel economy and optimized cooling.
• Reversing fan is hydraulically driven and automatically or manually back blows heavy dust and airborne debris from the cooling package so the operator can remain in the seat more due to not being forced to manually clean the fan throughout the day.
• Access to the coolers can be gained on the left or right side of the engine compartment doors or through the rear swing out door. Removing 4 bolts on each of the side panel doors provides cleaning access for the side coolers. The rear door is latched providing quick and easy access to all of the coolers maximizing uptime.