Land Rover to demonstrate ZF 9-speed automatic transmission; up to 16% fuel savings over standard 6-speed automatic
27 February 2013
|The ZF 9HP 9-speed. Source: ZF. Click to enlarge.|
At the upcoming Geneva Motor Show, Land Rover will announce the first 9-speed automatic transmission for a passenger car; Land Rover is the lead partner on the project, working together with ZF. The ZF 9HP transmission (earlier post) is specifically designed for transverse applications and front or four-wheel drive and can thus be installed in 75% of all cars produced worldwide, ZF notes.
Increasing the number of gear ratios from six to nine improves fuel economy and a correspondingly reduces CO2 emissions. (ZF suggests that the 9HP can provide fuel savings up to 16% compared to a standard 6-speed front transverse automatic transmission.) Smaller ratio steps give improved response during acceleration, improved shift quality, drive and refinement. The higher top gear not only reduces fuel consumption but the lower engine revs improve comfort and reduce noise when cruising at high speed.
(ZF says that in real-world testing at a constant speed of 120 km/h (74.5 mph), the 9HP reduced fuel consumption by 12% in a gasoline-powered SUV and by 16% in a diesel-powered SUV.)
Features of the 9HP include:
Planetary gearset with 9 speeds, 4 simple gearsets, and 6 shift elements. Gearsets are nested to save space.
Wide transmission ratio spread (nearly 10) with small ratio steps.
The first use of interlocking dog clutches in a passenger car powershift transmission.
Torque converter with excellent vibration and oscillation isolation for optimal comfort during starting (driveoff) and shifting.
Low engine speeds for increased fuel savings
The lowest ratio in the 9HP is far lower than the existing six-speed transmission and is specifically designed for off-road use, towing and more extreme on-road conditions such as gradients and altitude, giving the driver a heightened sense of control.
ZF describes the fast gear changes as being “below the threshold of perception.” Whereas the existing six-speed transmission makes shifts sequentially, the 9HP has a skip-shift function for much swifter downshifting under rapid deceleration or from greater driver input demands. The torque converter incorporates a multi-stage damper system for smoother pulling away and improved refinement.
An adaptive shifting system matches the driver’s needs, sharpening up during brisk driving then slipping into a more economical regime under more relaxed driving. Curve Mode, longitudinal acceleration and pedal position all control upshift prevention.
Fast-Off mode measures the rate of throttle release, anticipates further requests by the driver for high power, then holds the gear if necessary. If the driver requests a downshift when the vehicle is travelling too fast, the transmission will remember the request and make the shift when the speed drops to an appropriate level.
Despite the extra three gear ratios, the 9HP is only 6mm longer and weighs 7.5kg less than the outgoing six-speed transmission. The small package space is achieved by a number of innovative design features including a new hydraulic vane-type pump, which also contributes to improved efficiency, two patented dog clutches replacing bulkier conventional clutch packs, and an Intelligently Nested gear set.
Land Rover was chosen by ZF to be the lead partner on the 9HP and Land Rover engineers have worked in partnership with ZF engineers to jointly develop the transmission to suit the brand.
I wonder if Land Rover charges under $4,000 US for the ZF 9HP?
That's the amount BMW charges for it's range extender I3 genset hybrid option.
If oil jerks keep crying about Nissan's missing Leaf ICE, maybe Leaf should think about a 35HP motorcycle/genset option;
"extra €3000. This employs a 35bhp two-cylinder motorbike engine to act as on-board generator" http://www.carmagazine.co.uk/Drives/Search-Results/First-drives/BMW-i3-2013-electric-car-test-ride/
Posted by: kelly | 27 February 2013 at 07:33 AM
Yes Kelly. Most if not all current BEVs would be better off with very small on-board generator, at least until 2018/2020 or until 3x to 5x affordable batteries become available.
This new 9x transmission could be a good interim solution (at a price) for Heavies and gas guzzlers and Army Tanks?
Posted by: HarveyD | 27 February 2013 at 09:19 AM
Nissan Murano has had a 3.5l V6 and a CVT for 20/25 mpg for a decade. Plenty of power, room and good mileage in one 3800 lb. crossover SUV.
Posted by: SJC | 27 February 2013 at 09:51 AM
16% ?? Really? Because I've never seen an engine that varies it's BSFC numbers very much over a narrow RPM range. That is to say, the BSFC curve is very wide on modern engines. 6 speed transmissions are able to keep most engines well within the bottom of the curve in normal operation.
Posted by: cujet | 27 February 2013 at 10:20 AM
Land Rover's Evoque, which is the likely platform for this transmission, already gets much better fuel mileage than the Murano. The 9-speed transmission will increase its advantage.
There was an article recently on GCC about cars that require extra enrichment above certain threshold speeds. Perhaps that's the case here, and 75mph represents a threshold on the Evoque.
You must have read a different article. I have no idea how the stuff you wrote relates to this.
Posted by: Bernard | 27 February 2013 at 11:35 AM
@B, maybe a '9-speed automatic transmission' is expensive and even unnecessary.
Posted by: kelly | 27 February 2013 at 12:45 PM
"which is the likely platform for this transmission"
It says nothing about the Evoque, which is a 4 cylinder with 104 inch wheel base. That is like comparing a Murano to a Rogue, a Highlander to a RAV-4 or a Pilot to a CRV.
Posted by: SJC | 27 February 2013 at 01:12 PM
The car industry took its customers or many round trip rides before:
1. from 1 to 16 cyls and back to 4 cyls and possibly down to two cyls soon..
2. from 20+ inch wheels to 12 inch wheels and back to 22 inch wheels.
3. from 2 speed to 9 speed transmissions to CVTs.
This (and planned obsolescence) seems the way they have found to sell more cars.
Our 14-years old Camry with its small 14-inch wheels and 4 speed transmission is going very well at about 26 to 30 mpg. Our next Camry Hybrid will probably have 17 and 18 wheels and 6+ speed transmission or CVT.
Large 18 inch winter tires and wheels cost almost 2x as much as 16-inch tires and wheels.
A 9 speed transmission probably cost twice as much as a CVT.
Toyota's Prius III has small diameter wheels but has the best fuel economy???
Posted by: HarveyD | 27 February 2013 at 01:13 PM
Rez motor has a new patent in hydraulic hybrid transmission and work as CVT transmission , and cost less any transmission.
HYDRAULIC HYBRID TURBO TRANSMISSION (HHTT)
The hydraulic hybrid turbo transmission reduces emission and energy consumption up to 50%. The energy recovery from the breaking system is up to 80%, compared to the Electric hybrid vehicle which only recovers 25%. The HHTT system includes low-pressure storage, high-pressure accumulator, pump, and multi-stage turbines. The hydraulic hybrid turbo transmission operates without a torque converter, breaking system on the wheels, a large battery, and an electric motor. The hydraulic hybrid turbo transmission operates the vehicle in a direct drive mode at high speeds and in hydraulic mode at low speeds.
The number of turbines represents the number of gears; for example in a three speed transmission will be three turbines:
• Third gear : one pump works against one turbine
• Second gear : one pump works against two turbines
• First gear : one pump works against three turbines
The transmission will act as breaking system, when the three turbines turn in a reverse direction; the turbines will act as three inline pumps. This breaking system is the most powerful breaking system ever built.
The hydraulic hybrid turbo transmission is a:
• Energy recovery unit
• Energy management unit
• Automatic transmission
• Torque converter
• Breaking system
• And provides high pressure fluid for other uses such as a second breaking system, steering system, suspension system, and construction tools.
The hydraulic hybrid turbo transmission vehicle costs less than an electrical hybrid vehicle and performs much better. The HHTT also costs less than any conventional vehicle.
Comparing the hydraulic hybrid turbo transmission vehicle (HHTTV) with other hybrids vehicle (HV):
This new hydraulic hybrid turbo transmission with high performance, low emission, and low cost will dominate the automobile industries.
This will gain huge support from the Government, consumers, and the manufacturers.we need investor.
Posted by: mustafa rez | 27 February 2013 at 01:13 PM
@mustafa rez - sounds good, though wouldn't there be significant hydraulic friction losses?
"Electric motors often achieve 90% energy conversion efficiency over the full range of speeds and power output and can be precisely controlled." (wiki) is the present no transmission cost light vehicle EV approach.
Posted by: kelly | 27 February 2013 at 03:50 PM
This transmission is "specifically designed for transverse applications and front or four-wheel drive."
Based on Land Rover's current range, this describes the Evoque and the Freelander (sold as the "LR2" in North America).
There's no indication that the bigger Range Rovers and Land Rovers will switch to a transverse layout in the near future. The RR was just fully redesigned, and the RR Sport, Discovery (LR4) and Defender are expected to use the same longitudinal platform.
Posted by: Bernard | 28 February 2013 at 06:31 AM
Fine, my point was that Nissan had a large SUV with 20/25 mpg 10 years ago. This was and is a 3.5L V6 with 240+ hp.
Comparing a small crossover to a large one does not make a good comparison. People expect a RAV-4 with a 4 cylinder engine to get good mileage. When you can make a Highlander a hybrid and get better mileage than the small RAV-4, there is an advancement.
Posted by: SJC | 28 February 2013 at 10:20 AM