Mercedes-Benz has released details on the 4matic all-wheel drive system it will use in the upcoming CLA four-door coupÃ©, shown here in official spy shot pics. They’ve also gone to the trouble of explaining how a tailored 4matic system will be applied to the cooking CLA 45 AMG model.
On first reading, 4matic sounds a bit similar to the Haldex system employed by the Volkswagen Group, among others. That is, the Benz 4matic system will operate is front-wheel drive as a default setting in order to maximise fuel efficiency. Mercedes claims their all-wheel drive system will be around 25% lighter than similar systems used by other car makers.
When required, power is sent to the rear axle through an electrohydraulically actuated multi-disk clutch. Mercedes says the guiding principle of the system is to use it â€œas often as necessary, as rarely as possible.â€
The 4matic system will be coupled to a 7-speed double clutch transmission which has three settings: eco, sport and manual. In sport and manual modes the tolerances for the transfer of power to the rear axle are more focused, allowing for a quicker response and more dynamic handling.
Mercedes has hinted at the engine specs for the CLA 45 AMG saying the 2.0 litre turbo four will boast well over 400Nm of torque. So around 450Nm like the M135i, then?
Both the CLA 45 AMG and the A 45 AMG have been confirmed for Australia. The AMG versions will trail the Australian launch of their matching entry-level models by roughly six months.
The A 45 AMG is scheduled to go on sale locally in the latter half of next year, while the CLA 45 AMG is due to arrive in early 2014.
There’s more detail from Mercedes after the break, including some nerdy diagrams showcasing the 4matic’s tricky bits. Really, you have to check it out just so you can discover what an integrated power take-off unit is!
All-wheel drive for all
- Newly developed 4MATIC all-wheel drive for the CLA
Stuttgart. From next year, Mercedes-Benz will be offering a new variant of the 4MATIC permanent all-wheel-drive system with fully variable torque distribution. This new development is based on the front-wheel-drive architecture with transversely mounted engines. Like the other 4MATIC versions, it boasts high tractive power reserves and outstanding agility accompanied by optimum driving safety and energy efficiency. The new 4MATIC will also boost driving enjoyment in the particularly dynamic CLA 45 AMG which, like the series production model, is to be premiered in 2013.
The most innovative components of the new 4MATIC include the power take-off to the rear axle which is integrated in the 7G-DCT automated dual clutch transmission and the rear-axle gear with integrated, electrohydraulically controlled multi-disk clutch. This set-up enables fully variable distribution of the drive torque between front and rear axle. Additional benefits of this design are a lower system weight than is available from the competition and high efficiency. Similarly to the front-wheel-drive versions, all 4MATIC models also boast good energy efficiency.
The 4MATIC all-wheel drive is a completely new development tailored to the requirements of the new models with front-wheel drive.
Integrated power take-off unit (PTU) channels power to the rear axle
The new 4MATIC comes together with the 7G-DCT seven-speed automated dual clutch transmission. The power flux to the rear powertrain is provided by a compact power take-off unit (PTU) which is fully integrated in the main transmission and is supplied with lubricant from the latter’s oil circuit. This configuration gives rise to substantial weight advantages of up to 25 per cent in comparison to rival systems which branch off power by means of an add-on component with its own oil circuit. Together with the friction-minimised tapered roller bearings, the PTU achieves an excellent level of efficiency.
Completely new development with torque-on-demand rear axle
The electrohydraulically actuated multi-disk clutch integrated in the rear-axle gear unit provides for fully variable torque distribution. Basic principle: when the multi-disk clutch is open, the vehicle is driven almost exclusively by the front axle. When the clutch is closed, the rear axle comes into play. The drive torque can be shifted in fully variable mode between front and rear axle according to the given situation (torque on demand).
The system pressure to activate the rear axle is supplied in milliseconds by the rotor pump which is integrated in the rear-axle gear unit. The pump is activated automatically as soon as only minimal speed differences apply between front and rear axle. Pressure control is performed by an ESPÂ®-controlled proportioning valve.
Intelligent control systems for enjoyable driving
The 4MATIC is activated according to the basic principle of “as often as necessary, as rarely as possible”. This means that when the underlying conditions allow, the all-wheel-drive models run almost exclusively in particularly economical front-wheel-drive mode. As soon as the driving situation requires, drive torque is channelled to the rear axle as appropriate. The reverse process takes place just as quickly: as soon as additional drive torque is no longer necessary at the rear axle â€“ e.g. in case of heavy braking manoeuvres with ABS intervention â€“ the rear powertrain is deactivated and torque is reduced to zero.
In case of impending understeering or oversteering under load, the drive torque is first of all distributed such as to stabilise the vehicle. Only if these measures fail to have a stabilising effect do the control systems adapted to 4MATIC conditions, such as ESPÂ® or 4ETS, intervene to keep the vehicle stable.
With this strategy, the developers have managed to combine two key requirements defined in the performance specifications: optimum energy efficiency coupled with maximum driving dynamics and driving safety.
Individual: driving modes to suit personal driving styles
The torque distribution ratio is also dependent on the activated shift programme of the 7G-DCT dual clutch transmission. In ECO mode less torque is channelled to the rear axle, resulting in gentler handling and supporting an economical driving style at lower revs. In SPORT or MANUAL mode the activation times are shortened and more torque is distributed to the rear axle in the interests of a dynamic, sporty driving style. On the AMG versions, adaptation of the 4MATIC controller takes place in accordance with the three-stage ESPÂ®.
New 4MATIC featuring in the Mercedes-Benz CLA
The CLA-Class models which are set to appear next year and the particularly agile and powerful CLA 45 AMG will also benefit from the further advances in all-wheel-drive technology from Mercedes-Benz. The new Mercedes-Benz CLA adopts the avant-garde design of the Concept Style CoupÃ© into series production almost 1:1. In keeping with its sporty positioning, the CLA is available with high-torque turbo engines rated at up to 211 hp, sports suspension and the newly developed 4MATIC. The technical highlights include numerous driving assistance systems, such as advanced COLLISION PREVENTION ASSIST.
CLA 45 AMG: the most dynamic way to experience the new 4MATIC
As the high-powered top model of the new compact class, the CLA 45 AMG broadens the portfolio of Mercedes-Benz’s high-performance brand to offer a fascinating high-performance vehicle in this class, too. The newly developed AMG 2.0-litre four-cylinder turbo petrol engine will set new standards in its engine capacity segment: with maximum torque of well over 400 Newton metres and low fuel consumption, AMG is aiming to lead the competition. In conjunction with the specially adapted 4MATIC version for this engine-power class, the CLA 45 AMG will be one of the most dynamic, powerful and efficient four-cylinder coupÃ©s around.
The recently thoroughly overhauled SUVs and ATVs are also included in the 4MATIC model range â€“ the Mâ€‘Class, the GL luxury SUV and the legendary G-Class, which still retains its special off-road strengths after 33 years in production. The all-wheel-drive line-up from Mercedes-Benz further includes an exotic model in the guise of the SLS AMG Electric Drive. Four electric motors on this vehicle guarantee tremendous thrust, with fully variable and selective drive torque distribution to the individual wheels. And when the compact models featuring the new 4MATIC generation round off the range next year, it will really be a case of all-wheel drive all-round!
On track of CLS and Co.: 2013: premiere for CLA and CLA 45 AMG
- Mercedes-Benz CLA: new model from the segment’s inventor
- Concept Style CoupÃ© premiered in the spring becomes reality
- Avant-garde design coupled with high driving dynamics
- Mercedes-Benz CLA 45 AMG: elegant and athletic front runner
- New AMG 2.0-litre four-cylinder turbo petrol engine
- Superlative dynamism and efficiency
The new Mercedes-Benz CLA embodies in a production car the avant-garde design of the Concept Style CoupÃ© which had its world premiere at the Auto China fair this April. The exciting compact mid-range coupÃ© adopts the concept vehicle’s non-conformist, provocative and masculine lines. On numerous points of detail the designers have drawn inspiration from the SLS and CLS modern Mercedes classics â€“ examples being the sporty, self-assured front end, the powerdomes on the bonnet or the three-dimensional side design featuring an additional brawny muscle extending over the dropping line from the rear door to the boot lid.
In keeping with its sporty positioning, the CLA is available with high-torque turbo engines rated at up to 155 kW (211 hp), sports suspension and the newly developed 4MATIC. The technical highlights of the new design icon include numerous driving assistance systems, such as advanced COLLISION PREVENTION ASSIST PLUS. In addition to outputting visual and acoustic warnings when an impending danger of a rear-end collision is identified, the latter system is also able to carry out autonomous partial braking if the driver fails to respond to warnings and a danger of collision persists.
Five equipment and appointment packages which vary greatly in character are available to individualise the striking compact mid-range coupÃ© (length/width/height: 4630/1777/1437 millimetres). In keeping with the digital lifestyle of the CLA’s social media-savvy target group, smartphones can additionally be fully integrated into the vehicle’s display and operating system.
CLA 45 AMG: the most dynamic way to experience the new 4MATIC
As the high-powered top model of the new compact class, the CLA 45 AMG broadens the portfolio of Mercedes-Benz’s high-performance brand to offer a fascinating high-performance vehicle in the compact class, too. The newly developed AMG 2.0-litre four-cylinder turbo petrol engine will set new standards in its engine capacity segment: with maximum torque of well over 400 Newton metres and low fuel consumption, AMG is aiming to lead the competition. In conjunction with the specially adapted 4MATIC version for this engine-power class, the CLA 45 AMG will be one of the most dynamic, powerful and efficient four-cylinder series-production compact cars.
Perfect power transmission is ensured in the CLA 45 AMG thanks to the AMG SPEEDSHIFT DCT 7-speed sports transmission with dual clutch technology and performance-oriented all-wheel drive. The ideal basis for high cornering speeds and exciting, agile handling also comes courtesy of the AMG sports suspension with independently developed front and rear axles, electromechanical AMG speed-sensitive sports steering, AMG high-performance braking system and 3-stage ESPÂ® with “SPORT Handling” mode. The 3-stage stability programme is also applied to adapt the control strategies of the variable 4MATIC system:
- In “ESP ON” mode a safety-oriented driving programme supports the driver with clear-cut self-steering behaviour, i.e. essentially neutral handling characteristics.
- Briefly pressing the ESPÂ® button activates “ESP SPORT Handling Mode”. This dynamically oriented driving mode applies appropriate control strategies for later ESPÂ® intervention and increased drive torque at the rear axle.
- Pressing the ESPÂ® button longer activates “ESP OFF”. “ESP OFF” should only be used by experienced drivers on cordoned-off race tracks.
After pressing the brake pedal in “ESP SPORT Handling Mode” or “ESP OFF” mode, all ESPÂ® functions are available once again.