|EVDrive torque vectoring. Click to enlarge.|
EVDrive has developed and demonstrated an electric 4-wheel, 4-motor torque vectoring technology (Terra-Torque-Drive) specifically targeted at 4-wheel off-road powersports vehicles such as side-by-side Utility Terrain Vehicles (UTVs).
The Terra-Torque-Drive-powered e-UTV demonstrator uses four sealed liquid-cooled EVDrive EVD35 35kW/47hp peak drive sub-systems, de-tuned to ~30kW/hp each or delivering a total of ~160hp/120kW peak. At each motor shaft, ~66 ft-lbs (89 N·m) peak torque is delivered. The 4 gearboxes allow ratio changes with off-the-shelf gearsets. With the currently installed single speed gearsets at the CV joint of each wheel, 726 ft-lbs (984 N·m) peak torque is delivered. This is the kind of torque necessary to perform Zero Radius Turns with a fully loaded vehicle and perhaps even some extreme rock climbing.
With these gearsets, a top speed of 45 mph [72 km/h] is achieved with acceleration to this speed of less than 4 seconds if you get good traction—at zero speed all 4 wheels will break loose on dry asphalt!—Bob Simpson, EVDrive’s CTO & co-founder
EVDrive chose the 4-seat Kawasaki Teryx4 as a tech demonstration platform because of its short wheelbase, smaller turning radius, and large break over angle to minimize getting hung up on obstacles. EVDrive modified this UTV with complete removal of the gas engine and AWD mechanical drivetrain and replaced with a 160hp (119 kW) peak total version of the Terra-Torque-Drive.
EVDrive e-UTV Terra Torque Drive™ AWD Torque Vectoring Technology Demonstrator Video from EVDrive R&D Projects on Vimeo. Video (approximately mid-way) provides more detail on control touch screen for the Terra-Torque-Drive, specifically the interface to the in-house developed VCU.
|Terra-Torque architecture. Click to enlarge.|
Unlike the stock Kawasaki Teryx4 UTV mechanical AWD drive, no additional mechanical losses are incurred in the Terra-Torque-Drive, regardless of AWD mode from lack of transmission, driveshafts and differentials.
The Terra-Torque-Drive is a customized version of the general and modular EVDrive-Train architecture used on all EVDrive conversion projects, with an in-house developed scaleable torque vector software platform added running on the EVDrive VCU (vehicle control unit), which supports new traction modes with inputs from all driver controls plus vehicle sensors such as accelerometers, etc.
Off-road UTVs are ideally suited to our torque vectoring technology where only single fixed speed reduction is required per motor-wheel to attain 55-75 mph top-speeds with the type of high RPM brushless motor technology we employ.—Steve Tice, EVDrive COO, co-founder
Addition of a single-cylinder 15kW (20hp) range extending engine (REX) can also deliver 120vac of electrical power. The REX gas engine can be modified to run on LPG as well offering additional emissions and operational cost advantages.
Similar to our 25kW REX technology installed in our Series-PHEV BMW325 tech testbed but smaller, our custom high voltage 15kW-single cylinder (ICE) powered REX for the UTV is located between the rear seats—so with this sub-system, competing against top 4-seat UTVs in range will not be a problem—certainly the performance meets and beats stock UTVs we have tested.—Bob Simpson
Approximately 323,000 UTVs were retailed in North America in 2012, according to Power Products Marketing (PPM), a market research firm. PPM found consumer models (for example: Polaris RZR XP900) accounted for around 35% of total sales; Prosumer models (example: Deere XUV825i) garnered around 55% share, and commercial models (example: Bobcat Toolcat) were responsible for about 5% of sales. The new EVDrive technology could apply to all 3 market segments.
According to EVDrive, a Terra-Torque-Drive-powered UTV with a 15 kW (20 hp) EVDrive Range Extender (REX) installed would deliver:
Highest efficiency 4wd drivetrain on any UTV today (least mechanical losses);
Adjustable hill descent control (regen putting energy back into the vehicles battery system from each of the 4 wheels);
Dynamic torque vectoring modes both for high and low speed operation, e.g. industry unique “Zero Radius Turning” and high speed active torque vectoring allows for better and safer handling off-road;
Torque and power from -100 to +100% can be dynamically sent to any wheel, in either direction, in any combination, at any time.
Series hybrid with optimized internal combustion engine powered REX to allow for longer range matching or exceeding gas powered UTVs sold today. (REX is a high voltage specialized generator-LPG, gas or diesel powered REX engine easily adaptable, no mechanical connections to vehicle);
120vac power from onboard battery pack, backed up with the REX for general utility use;
Lower cost to maintain and operate. Superior fuel economy, estimated average 50-100% better, and for short trips, no fuel may be needed at all. Plug-in to standard electric car chargers;
Superior straight-line and rough loose material, curvy trail acceleration;
Greater river depth traversal possible due to completely sealed liquid cooled e-motors/power electronics; and
Torque vectoring software platform allows new traction capabilities to be supported like “apps” without costly mechanical NRE expenses to the OEM; OEM can provide customers software updates for new capabilities.
Planned traction modes beyond what is currently running on the demonstrator include: auto dynamic terrain type posi-traction control, variable inclination angle offset descent control, zero radius turns on incline, emergency 4-wheel panic braking/stop and boulder climbing.
EV West is partnering with EVDrive to deploy and demonstrate Terra-Digital-Torque-Steer all-wheel torque vectoring technology on full-size off-road vehicles.
EVDrive is a design, engineering, systems integrator and low-volume manufacturing firm that develops both hybrid and electric-only powertrains for new or conversion of existing vehicles which yield “no operational or performance compromises” when compared to their internal combustion engine designs. It has been developing its own systems, components and software, and focuses primarily on high performance electric drive systems in support of OEMs, commercial fleets and vehicle conversion companies.