Truck makers and technology proponents have been dancing around the fringes of harnessing kinetic energy for some time. Regenerative braking is the best example, but its most effective applications are local and regional trucks with higher exposures to stop-and-go driving.
At the North American Commercial Vehicle Show in late October in Atlanta, ConMet showed off its new PreSet Plus Electric Hub (eHub), a motor/generator packaged to mount at the wheel-end within the existing space between the axle spindle and the brake shoes.
ConMet says the eHub can be developed to be placed within hybrid or fully electric commercial vehicle applications. It uses off-the-shelf brake components, so no custom brake components are required. As a modular design, it can be packaged with existing axle configurations.
“We were able to leverage our hub technology expertise and essentially package the motor within a slightly modified version of a hub that we already make,” Caleb Lander, ConMet's product manager for electrification, told HDT in an interview. “We use a drum brake as our braking system because it allows the eHub to fit nicely behind the wheel and encapsulate the motor.” (While drum brakes continue to lead in the trailer market, ConMet plans to offer an air-disc-brake solution in the future.)
A Building Block for Electrification
The in-wheel motor/generator concept opens all sorts of doors for electrification. ConMet’s eHub is a flexible electrification system, intended to be a building block that can be dropped into many different applications in the commercial vehicle market.
When used as drive motor, the greatest advantage is weight savings. Because the motor drives the wheel directly, it does away with gear boxes and driveshafts and any of the other content found in a centralized drive system. This drives down the total weight of the drivetrain package considerably.
“The complete system, which includes the motors, the brakes, the hubs, all the controls, the cooling units, it's going to be at least 1,000 pounds less than an e-axle,” Lander said.
ConMet is pursuing applications across the Class 5 to Class 8 range, including as a "helper axle" on tractors and buses, and in some medium-duty applications in either a hybrid or full-electric configuration.
A New Way to Power Trailer Reefer Systems
ConMet will initially launch a trailer system, where it can supply power for auxiliary electrical systems on the trailer, as well as replace the diesel engine for trailer reefer systems.
“It could be used for practically anything that requires additional power over and above what you would typically have on a trailer,” Lander said. “It’s a plug-and-play system geared toward overall savings to fuel economy and reductions in emissions.”
ConMet sees the best fit presently as power for a reefer application on regional or urban delivery routes. Depending on the driving cycles, the eHub, batteries, and controllers will supply enough power to run the refrigeration unit throughout the day, cycling on and off, and generating its own power directly from the rotation of the wheels.
The eHub integrated controls also allow for regenerative braking mode or propulsion assist mode, enabling the utilization of all the power captured throughout the day to optimize fuel savings – knowing that at the end of the day it can be plugged in again for overnight charging using shore power.
“We will keep the battery as topped off as is reasonable based on the route that fleet is running,” Lander said. “If for some reason you have a long stop, for instance, we want to make sure that you have enough power to continue running the reefer while at that stop.”
In scenarios where the battery is kept fully charged, eHub energy can be used to power auxiliary electrical systems on the trailer, too, allowing for basically silent operation while at a delivery site. That opens up opportunities for delivery times that might be frowned upon due to noise restrictions.
“We can eliminate the use of the diesel generator, reducing noise and emissions, which brings other benefits to whoever is running these systems, such as idle reduction and improved fuel efficiency,” Lander said. “These are all really important to fleets nowadays.”
The first trailers using ConMet’s eHub are scheduled to hit the road this month, followed by a controlled rollout of early release units beginning in the first quarter of 2020. The production release is slated for the end of 2020.