After a lengthy wintertime test-drive of the 2022 Hyundai Santa Cruz in the dead of a Northern Ontario winter, I wanted to dig into the nuts, bolts, sensors, and computers behind this compact pickup’s HTRAC AWD system to learn more about how it works.
To help reveal some of the finer details of the system’s parts, capabilities and operation, I reached out to Hyundai’s Terry Tizzard, an AWD expert who has played a role in training Hyundai dealers on the brand’s AWD technology.
Let’s begin with an anatomy lesson: “the system is a traditional layout for AWD, from a front-wheel drive platform” Tizzard explains.
My tester ran a 2.5-litre turbocharged four-cylinder engine up front, teamed with an 8-speed automatic transmission. To that hardware arrangement is attached a front differential and transfer case, a front prop shaft, a torque-controlled AWD coupling, and a rear differential. There’s also an AWD control module which we’ll get to later.
Basically, this collection of hardware components allows power from the engine up front to be delivered in a widely-variable split between the front and rear wheels, by connecting the front and rear axles together physically with the prop shaft and AWD coupling.
The AWD coupling is a key component of the HTRAC system. Imagine grasping a rotating shaft with your hand. The harder you squeeze, the more of the rotating force (ie. torque) of the shaft is applied to your fingers, hand, and arm. More clamping force in your grip directly translates to more torque applied to your body.
The grip and clamping force in the HTRAC AWD coupler comes from an electronically controlled clutch that works like your hand in the example above. The human hand clamps and releases because of electronic signals sent from our brains. The AWD coupler’s clutch clamps and releases at the direction of electronic signals sent its way from a computer brain– the AWD control unit I mentioned earlier.
The principle is the same: the brain sends signals to change clamping force, and therefore, the torque transfer between two things — be they an imaginary rotating shaft and your arm, or the front and rear axles of an AWD system. However, the electronically-controlled clutch in the AWD coupler can change its grip, or clamping force, precisely, continuously, and within milliseconds — much faster than the muscle fibres in a human hand. This gives the system precise control over exactly when and how much power is transmitted to the rear axle.
Running the show is the HTRAC AWD control unit, which considers input from the Accelerator Position Sensor, Steering Angle Sensor, Wheel Speed Sensors and Yaw Sensor.
“The accelerator position sensor is one of the primary inputs leading many of the decisions the HTRAC system will make” explains Tizzard. “The system is designed to provide power to the rear wheels from a stop in order to provide confident acceleration when you are ready to move. This pre-load assists in making sure the 311 lb-ft of torque, readily available between 1,700-4,000 rpm, makes it to the ground with limited wheel slip.”
2022 Hyundai Santa Cruz Ultimate Photo by Elliot Alder
From the driver’s seat? Even in deep snow and icy conditions, the Santa Cruz’s AWD system sees plenty of off-the-line bite with no slippage of the front axle required before rear-wheel traction is engaged. The truck gets off the line with all four wheels powered from the get-go, no digging or slipping required. Drivers can expect a more direct response to throttle inputs, straight-as-an-arrow acceleration on snow and ice, and the ability to easily put plenty of that low-end torque to the road, even if it’s buried in snow. The rear axle has a deep reserve of additional torque that can be called on instantaneously if required for heavier use, like fast starts, towing, or a steep climb.
“The system will continue sending power to the rear wheels, increasing the ‘push’ as required to maintain forward momentum” explains Tizzard. ”This all happens in hundredths of a second — faster than we can blink, and certainly faster than we can realize the system has taken over”.
Traction is optimized automatically on a continual basis, and usually so smoothly that the driver doesn’t notice anything going on beneath them.
Advanced electronic control also allows for some additional capabilities, including dedicated terrain modes that call special programming into action to better meet the specific driving requirements of snow, mud, or sand.
In each mode, the operation of various systems including the traction control, throttle, transmission, and AWD system are optimized.
2022 Hyundai Santa Cruz Ultimate Photo by Elliot Alder
On my test drive, I found the Santa Cruz’s default automatic setting sufficient in most driving, though use of the SNOW mode in deep powder and on ice makes for acceleration that’s notably smoother and less dramatic.
Tizzard explains that “Snow mode is designed with winter driving in mind and will provide additional pre-load to the rear wheels from a stop. It is also quick to respond in other situations. The AWD system will control the torque delivery to keep the vehicle moving based on the driver’s request.”
Use of Snow mode also balances power applied to the driving surface to reduce the potential for wheel slippage.
“While torque is being meted out in an even split to get you moving, the throttle application can be smoothed out to avoid abrupt acceleration, thereby providing smooth and progressive momentum” Tizzard says.
With Snow mode engaged, the Santa Cruz focuses on building smooth momentum. With the throttle smoothed out and the rear wheels sharing more of the work of getting the Santa Cruz moving, the driver benefits from a more straightforward climb to their desired speed, with minimized wheelspin and drama. It’s all about imparting a feeling of confidence.
2022 Hyundai Santa Cruz Ultimate Photo by Elliot Alder
“When driving on a slippery road, the engine RPMs may not increase even if you press the accelerator pedal aggressively. This is the Santa Cruz’s stability control and AWD systems all working together to maintain the stability and traction of the vehicle. It makes sure the driver gets the forward momentum they are looking for… Snow mode adjusts left and right wheel slip control, engine torque and shift patterns according to available traction levels” he adds.
Similar system reconfigurations take place in other drive modes, including Mud mode’s focus on smooth power delivery and sufficient driving force to ‘start’ the vehicle off, and Sand mode, which uses further transmission shift-point adjustments to make it easier for the driver to maintain momentum.
In normal conditions using the Normal drive mode, Tizzard says that the Santa Cruz starts out with some pre-load of torque to the rear wheels, and that the system can rapidly dial in more or less rear-wheel torque depending on the information pulled from the AWD control unit.
Remember: powering all four wheels is less fuel-efficient. The ability to quickly adjust the torque applied to the rear axle on demand means extra grip is available the millisecond it’s needed, but with less of a hit to the driver’s fuel bill.
Keyword: Deep Dive: Hyundai Santa Cruz AWD system explained