Compass Trailhawk – Engineered To Take On The Beaten Road

July 2019 Latest Edition Technology Jeep Compass Trailhawk
Compass Trailhawk – Engineered To Take On The Beaten Road

Having tasted success in the Indian market with the Compass SUV, Jeep is now preparing to introduce the Compass Trailhawk in a bid to drive fresh appeal in the market. Sitting above the Limited variant, the Compass Trailhawk is a specially designed SUV that draws strongly from Jeep’s rich history with SUVs that are capable of taking on the beaten path. We not only sampled the Compass Trailhawk, but also got to learn more about the extensive work carried out by various teams at Jeep. Read on to learn just how much has changed on the upcoming Compass Trailhawk.

Jeep has awarded the Compass Trailhawk with its highly coveted ‘Trail Rated 4x4’ badge, making it an immensely capable off-roader. With strict specification targets to get the Trail Rated badge, the Compass had to be re-engineered on many fronts. Jeep will also be introducing its BS VI-ready diesel engine mated to a nine-speed automatic transmission on the new Compass Trailhawk.

DRIVELINE INNOVATION

With the 2.0 l, turbo-diesel mill belting out 350 Nm of torque, Jeep’s engineers had to choose the best transmission that would optimise the Compass Trailhawk for on-road as well as off-road performance. Back in 2014, the Jeep co-developed the nine-speed transmission with ZF and has since then licensed its production at two facilities in the US. Coupled with the engine, the nine-speed transmission offers the driver a 20:1 crawl ratio, which enables it to cross most hurdles effortlessly. The torque curve, especially while driving off-road at low rpms, provides drivers enough power to crawl over just about any terrain.

Jeep will introduce the new BS VI compliant diesel engine on the Compass Trailhawk. Using DPF, SCR & AdBlue technology, Jeep has enabled the Compass Trailhawk to run on BS VI and BS IV fuels

With the nine-speed automatic transmission, Jeep was able to select different final drives. The primary gears were set on the basis of the architecture in the gear arrangements of the transmission. With the Compass Trailhawk, engineers started out with a 28:1 reduction gear and a 4.33 final drive. Off-road, however, the Compass Trailhawk runs a low gear of 4.7 with the 20:1 crawl ratio that gives it the capability to roll over most obstacles and surfaces.

Jeep has implemented a disconnecting driveline with a power take-off unit (PTU) that it first brought to the market in 2014. While many companies have worked on a front wheel drive architecture that disconnects the rear axle, Jeep was the first to bring it out on a production model. The disconnecting driveline improves fuel economy and is advantageous on and off-road, using the same hardware and controls. Further, with the Selec-Terrain System, the vehicle is able to predict when four-wheel drive (4WD) is required, when to hold a gear and when to switch to a low gear. This makes the vehicle very capable off-road even if the driver is a novice.

Based on the architecture, the driveline comes with a dog clutch in the PTU, which is an on-and-off unit. The driveline also features a wet clutch in the rear drive module that is infinitely variable. This has been used on road to improve driving dynamics, aiding on turns and slippery surfaces such as rain, sand or snow. The same system off-road can be connected to do much more. At low speeds, there is no need for a front to rear axle differentiation, and the system can send as much power that the rear axle can take.

Here, the interesting usage is of the wet clutch that is not meant to absorb energy, but rather serves as an on-and-off clutch. The clutch pack on the Compass Trailhawk uses many plates and more fluid for cooling because it is slipping often. Engineers have partially clamped it to allow some slip. With the gear arrangements from left to right differentiation on the rear axle or the front to rear axle, it has to absorb some of the slip, as it is acting as a centre differential. This same hardware has allowed Jeep to disconnect and go into two-wheel drive (2WD), and also to have complete control while driving off-road. These small pieces that make up the driveline are also one of the secrets why the Compass Trailhawk has earned its Trial Rated badge.

The ZF nine-speed automatic transmission has enabled engineers to develop a powertrain that offers dual use (Image for representation purpose only)

RE-ENGINEERED STRUCTURE

To earn a Trail Rated badge, Jeep has strict compliance figures. The Jeep Compass Trailhawk features reworked approach, departure and break over angles. The company has also improved the ground clearance apart from making a few other changes to the layout and construction. The challenge for Jeep was to re-engineer the approach and departure angles on the Compass Trailhawk. The Trailhawk features a 26.5 ° approach angle, 21.2 ° break over angle and a
31.6 ° departure angle. Further, the ground clearance has been lifted to 205 mm. To redo the approach angle on the Compass Trailhawk, the frontal area had to be shortened and brought closer to the wheel. With requirements such as pedestrian protection through energy absorbing foam and placement of the cooling module in the front, it was a struggle for Jeep engineers. However, they made adequate adjustments to come as close as possible to their initial targets.

Reworking the departure angle was a bigger challenge as engineers needed to reduce the muffler size to accommodate the urea tank. With a delicate urea tank that comes with a pump, heater, sensors and pipes for fuel fill and the filler tube, Jeep had to put in skid plates underneath to protect these components. These also affected the clearance and departure angle. Engineers also had to make tweaks to the suspension, tank and muffler size to achieve internal targets. Overall, the Compass Trailhawk features four skid plates on the underbody protecting the engine, fuel tank, ad blue (urea) tank and fuel lines.

The Jeep Compass Trailhawk also features Frequency Selective Damping (FSD) that can be tuned to precision and the suspension features hydraulic rebound stoppers to improve the rebound and recovery of the dampers, offering improved performance both on and off the road. Another change made to the Compass Trailhawk is the snorkel height that has been increased to 840 mm as opposed to its setting of 720 mm on the Compass Limited variant. Further, the first three slats from the left on the front grille have been blocked off to enhance water wading performance. Jeep has also bolted an all-independent light weight suspension and improved the structural stiffness for better handling.

Re-engineered approach, departure and break-over angles make the Compass Trailhawk immediately differentiated from other variants. The ground clearance is noticeably higher

ROUND-UP

Jeep has borrowed synergies from the heavy truck industry that needed to meet emission regulations earlier and have implemented a Diesel Particulate Filter (DPF), Selective Catalyst Reduction (SCR) and use urea injection (AdBlue) to achieve BS VI emission compliance. These technologies also enable engine operations on BS IV fuels. Combined with the nine-speed automatic transmission, these technologies have given the Trailhawk greater efficiency in terms of fuel optimisation.

Further, it has enabled Jeep engineers to develop a vehicle with a powertrain that features a high torque diesel engine and possibly the best transmission layout to optimise the torque for low gear application. Jeep has efficiently executed the construction of a disconnecting driveline, which has made the Compass Trailhawk exciting to drive both on and off the beaten path.


TEXT: Joshua David Luther

PHOTO: Bharat Bhushan Upadhyay