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24-05-2011, 08:14 PM
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Chairman & Administrator
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SZ Territory - NVH
APRIL 7, 2011
NEW TERRITORY: REFINED, QUIET AND COMFORTABLE
"We carefully studied and improved every element of the new Territory to make it a more comfortable and pleasant vehicle for journeys of all kinds."
- Michael Stellamanns, NVH Manager Ford Asia Pacific and Africa
Ford Australia has introduced an optimised suite of sound-absorbing and sound-reflective materials, features and systems on the new Territory resulting in impressive levels of refinement and quietness.
A comprehensive sound-deadening package has been added to both TDCi V6- and I6-powered Territory models, enabling an impressive reduction of in-cabin noises that originate from a variety of sources.
To help achieve this Ford engineers paid close attention to a number of essential areas.
"The new Territory represents a significant improvement in the key area of refinement by reducing powertrain, driveline, wind and road noise," Michael Stellamanns, Ford Asia Pacific and Africa's NVH Department Manager, said.
"This is critical because quality is a vital part of any product, and the new Territory's refinement – its excellent Noise, Vibration and Harshness properties, referred to as NVH – helps communicate the engineering excellence that underpins this new model."
"The original Territory was a good base from which to work. Improving our existing results was going to be hard but we set stretch targets in our planning and benchmarked the new Territory against some expensive competition," he said.
Ford Australia naturally benchmarked the Territory against its main segment competitors, such as the Holden Captiva and Toyota Prado diesel. But with a desire to go even further, Ford set challenging refinement targets for its engineers and sought to exceed the benchmarks set by a number of luxury SUV brands and models, such as the Landrover Discovery and BMW X5.
"We wanted this new model to be competitive with far more expensive SUVs in terms of NVH. The new Territory achieves, and in some cases, exceeds the targets we set for vehicle NVH and hence overall refinement," Stellamanns said.
"We took all the outstanding attributes of the current Territory, put them under the microscope, studied and improved them.
"Customers will instantly notice and appreciate the exceptionally low levels of noise in the cabin," he said.
All of these enhancements have been engineered in Australia for local customers.
About NVH
NVH is not solely about providing sound deadening in a vehicle's cabin. It also involves developing the vehicle's metal architecture. Importantly, it addresses the need for the structural interface between body and power-train to perform in a certain way to either avoid being a resonator or an inadequate conductor of vibrations.
The new Territory's components have been designed to avoid both.
On top of this, Ford Australia has introduced an optimised suite of sound absorbing materials as well as barrier treatment features on the new Territory,
To Ford's skilled NVH engineers, the introduction of the new Territory's enhanced powertrains and optimised structural elements revealed themselves as opportunities to enhance the vehicle's refinement.
Advances in computer-aided engineering (CAE) have enabled significant NVH improvements from the body-in-white stage through to the final build of the new Territory.
Overall, this extensive and thorough work has resulted in impressive levels of refinement and quietness.
Power-train and structure-borne noise
Significant time and effort was invested into tracking and managing the body-based sources of noise that were transmitted into the cabin of the original–model Territory. This investigative work paved the way for Ford's NVH engineers to produce a world-class result.
Many of the improvements to the new Territory involved the interaction of the TDCi engine with the bodyshell and working to eliminate any annoying sound paths through the vehicles structure.
As a result there are new engine mounts and a revised transmission mount complemented by an all-new isolated cross-member. This provides a second level of isolation at the back of the six-speed automatic transmission on the all-wheel drive models.
What's more, the new sub-frame fitted to the new Territory not only provides a weight saving of 14kg (down from 44kg to 30kg) it also delivers other technical benefits. These include enhanced durability, improved low-frequency vibration and harshness as well as improved vehicle dynamics.
To install a V6 engine into a vehicle platform primarily designed to accommodate an in-line six-cylinder motor Ford's engineers had to overcome several packaging constraints. As a result, the company even went to the trouble of re-engineering the front differential to be mounted on the engine sump in all-wheel drive models, as opposed to mounting it to the chassis which is the method used on the outgoing model.
Stellamanns: "While this diff-on-sump architecture provides a number of excellent attributes, including the management of any drive-line imbalance-related booming sounds, this design also has the potential to generate new noise and vibration issues. This is because the front-mounted driveline now creates a direct path for vibrations from the engine to the vehicle's structure via the front suspension."
To avoid this, the new Territory's drive-train engineering team developed an active transfer case into the design of the front drive-line for all-wheel-drive models.
When the driver is stationary in DRIVE and has their foot on the brake while the engine is idling, a clutch mechanism within the active transfer case decouples any driving forces applied to the front drive shafts to cancel out this structure-borne path.
These invisible forces can have a noticeable impact on a vehicle's refinement, so we ensured that even when sitting at a set of traffic lights our customers enjoyed the best possible ride.
Sound package
With the arrival of the turbo-diesel V6 engine in the new Territory, a significant amount of engineering effort was dedicated to the vehicle's sound package, and in particular engine encapsulation, or the sealing of sound beneath the new Territory's bonnet.
Ford's NVH supervisor for the new Territory, Manu Jean, said the original model was designed around the petrol I6 engine.
"The introduction of the new turbo-diesel V6 engine initially offered some challenges in terms of its sound package," he said.
"Diesel engines are inherently louder than their petrol counterparts at commonly used engine speed and load ranges so we had to be very clever with our TDCi quietness pack."
One of the clever solutions in Territory's overall refinement package is its dash outer-absorber which is fitted in front of the steel firewall in the engine bay. This bulkhead absorber now features a special polyamide film / screen inserted between the scrim and lofting of the part to limit the transfer of engine noise through the firewall.
It acts as a barrier to the noise from the engine and works in conjunction with the sound absorbing properties of the polyester lofting within the part to help limit the sound penetrating into the new Territory's interior.
This innovative design is a world-first on this type of part, and results in a significant improvement in the abatement of high frequencies that contribute to interior sound levels and sound quality.
The Articulation Index, which is a metric used to characterise speech intelligibility (the ability to converse freely without raising one's voice) measured a five-to-ten percent improvement with the new part, equating to approximately a one point improvement on a subjective rating scale of ten.
Manu said the new dash outer absorber, in combination with the vehicle's steel firewall, acts, in effect, like the double-bulkhead designs typically found in high-end European vehicles, but without the cost or engineering complexity.
"Given we were working with much of the current-model's body structure we decided not to engineer a double bulkhead," Manu said.
"Our new dash outer absorber is a critical part of the overall sound package improvements we achieved in the new TDCi Territory. We benchmarked many competitive and high-end vehicles and came up with a solution that essentially achieves the same engineering result as a double bulkhead design.
"What's more, this solution's cost-effectiveness gave us opportunities elsewhere."
To complement the effectiveness of the upgraded sound package, Ford's engineers also paid specific attention to the "pass-throughs" of the firewall. For example, the rubber sealing boot that shrouds the steering column as it passes through the vehicle's front bulkhead was known to be an airborne path for in-cabin sound transmission. The new Territory comes fitted with a double rubber boot seal featuring two layers of rubber with an air-gap in between, providing greater noise attenuation. The effect is similar to household double glazing.
Improved pass-through-dash air-conditioning and heater grommet seals also improve the sound attenuation and contribute to in-cabin refinement.
To further attenuate under-bonnet engine sounds Ford's NVH engineers added upgraded dashboard and floor inner insulators. This additional barrier material thickness improves noise attenuation by one-to-two dB.
In addition to these sound package improvements, all designed to attenuate interior noise, significant effort was spent developing appropriate engine encapsulation features to control vehicle exterior noise.
Extensive testing was carried out to reduce the diesel "cackle" at idle from echoing into the cabin from around the car.
"We worked hard to exceed the targets we set for the 'drive-through test', such as when a driver is idling stationary at a toll booth or take-away restaurant window, usually next to a wall," Jean said.
"In such cases the sounds from the engine often reverberate against the road and wall and enter into the car as the driver's window is down. We don't have that problem in the new Territory TDCi."
A new comprehensive engine undertray with side covers has been developed and is now fitted under the engine of the new Territory. This provides a strong barrier and absorbs engine noise to reduce sound levels not only entering the passenger compartment, but also radiating away from the vehicle.
At the top the new full-size bonnet absorber covers much of the engine bay and works in unison with the engine's acoustic cosmetic cover to absorb the high frequency noise typical of diesel combustion.
A new transmission tunnel absorber complements the engine encapsulation package by capturing engine and transmission noise around the transmission area, and reducing the sound levels both entering the passenger compartment and radiating away from the vehicle.
The results are reduced interior and exterior noise, improved refinement and a three-to-four percent improvement in the Articulation Index.
In the simulated drive through testing devised to measure NVH performance, the new Territory is quieter than the Land Rover Discovery by eight AI percentage points – approximately one point improvement on a rating scale of 10.
Ford engineers also focused on improving the vehicle body leakage rate, also known as air leakage.
"We paid particular attention to minimise or seal gaps in the body to avoid not only leaks but also creaks and groans," Stellamanns said.
"We have sealed them to get to a very low leakage number. Doing this removes all airborne paths that permit sound travel through the body's cavities to the cabin interior."
Ford engineers traced noise levels from their source and where possible, eliminated them. Improved noise absorption and noise path sealing from rear extraction vents to the interior have resulted in a more refined and quieter area for the second- and third-row seating areas.
"This is all part of the attention to detail in the car, leaving no stone unturned to ensure engine sound does not enter the cabin," Stellamanns said.
The I6-powered new-model Territory shares the TDCi's engine sound-deadening pack and a host of other upgrades, from the new Electric Power Assisted Steering (EPAS) system to the all-new engine sub-frame and engine mounts, both of which contribute to Territory's new levels of refinement.
"We believe that we now have an even more exceptional vehicle with the new Territory. Our customers will also see this - and in our case, hear it - when they drive it."
At a glance: major NVH enhancements for the new Territory
* Extensive sound deadening package
* Sound-deadening dashboard bulkhead package
* Acoustic windscreen (TDCi)
* Improved body sealing
* Minimised diesel "chatter" in cabin at idle
* All-new EPAS (Electric Power Assisted Steering) system
* Redesigned engine mounts
* Active transfer case (TDCi)
* Isolated cross member support
* All-new engine sub-frame and engine mounts
* Powerful 800-watt twin engine cooling fans (TDCi engine)
* Reduced wind noiseSource: Ford Media
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