Explained: Tenneco’s DRiV Electronic Suspension
Making Them Ride as Well as They Haul and Tow
As everyone knows, hard-working trucks need stiff, strong springs and shocks to tow and haul heavy loads. But those typically make them ride and handle like old, horse-drawn buckboards when they’re lightly loaded—which, for most of us, is most of the time. Some truck-makers do better than others at light-load dynamics, but even the best leave something to be desired.
So can anyone offer the heavy towing and hauling capabilities many of us demand without the uncomfortable reality of typically trucky unloaded ride and handling? Actually, the chances of that are looking good. High-tech global chassis performance supplier Tenneco, which has marketed continuously variable semi-active suspension (CVSA) technology—primarily on high-end European sedans and CUVs—since 2002, will soon launch a simpler, less expensive semi-active damping system called DRiV (Digital Ride Valve) aimed (at least initially) at pickups and truck-based SUVs.
This DRiV digital suspension technology now under development for a 2020 launch has an integrated modular design with sensors and software controls nestled inside the damper itself. With no external valves or electronic control unit, Tenneco says it is easy for the OEM to integrate into the vehicle’s existing suspension with little re-engineering of mechanical or electrical systems. It offers eight discreet damping settings with or without a driver interface (through an infotainment screen or drive mode selector) and uses a simplified “gateway” module to communicate with the vehicle’s existing controller area network (CAN) bus.
As we experienced in a series of low-speed test drives of Tenneco-owned Chevrolet Silverados over and through strategically placed surface events and chicanes on a twisty course near Detroit, the DRiV dampers improved both ride and handling while significantly reducing shake, bounce, and brake dive. There was no question the DRiV-equipped truck, both unloaded and with 400 pounds of ballast behind its rear axle, was dramatically better in feel and performance than the (near-identically equipped) stock truck.
“The printed circuit board (PCBA) inside the damper has sensors, accelerometers, and the electronic intelligence integrated into it,” says Daniel Keil, Tenneco chief engineer - OE Business, Vehicle Dynamics and Product Engineering. “And we get steering, braking, tow/haul, and off-road mode CAN message data from sensors already on the vehicle.”
Are these dampers and their internal PCBAs sufficiently protected from the dirt, water, snow, and slush that hard-working trucks will experience over time? “We have done a lot of work to protect those things.” Keil responds. “Sealing is very important, and we will follow customer requirements on the anti-corrosion coating of the steel damper tubes.”
Will this DRiV technology also be used in passenger cars to provide smooth ride under normal conditions but transition to crisp, athletic handling on demand? “Yes, it will be calibrated to each vehicle with the OEM based on how the manufacturer wants its DNA,” he says. “The strategy we use in our algorithms is to call for control only when it’s needed. So if you're cruising on a smooth freeway, the dampers will be in soft mode most of the time. But if something jumps out in front of you and you do a lane change, they will go into a controlled mode with more damping. We will tune the passive valving before we add the semi-active control, then the system decides how much you need and when you need it.”
What will OEMs have to do to integrate this system into their vehicles? “They'll have to integrate communications to the gateway and harnesses to our system. The gateway is the communications interface, smaller than a cellphone, between our system and theirs. Then the calibration will be a joint effort between us and them. It fits in the same space where a normal shock does, so the rest of the suspension does not have to be touched.”
He adds that this technology does not limit a vehicle’s cargo or towing capabilities. “The intention is that it can do anything the truck can do,” he says. “It has to be able to encompass the limits set for the vehicle by the OEM. And it will reduce the durability loads on the vehicle because it will have better control and hit the suspension stops less often.”
Tenneco says that more than 6 million of its CVSA systems have been featured in 40 different models from 10 (mostly premium European) brands over the last 15 years, and it is now expanding their availability to the North American SUV/CUV market. And while the simpler DRiV system will be initially aimed at pickups and SUVs—especially those used for towing—beginning in 2020, there may eventually be opportunities for it in a wide variety of vehicles.