Driveline and Chassis Technology for car

Driveline and Chassis Technology for CarsZF Friedrichshafen AG Corporate Headquarters 88038 Friedrichshafen GermanyPhone +49 7541 77-0Fax +49 7541 77-908000050 750 101 f S V U 6007Cars move people – both physically and emotionally. But it’s not just stun-ning design and powerful engines that fascinate people. There is also a great deal of interest in the more intelligent concepts that will make mobility and the thrill of the open road compatible with fuel and resource savings, and even more personal safety. These are by no means confl icting aims for ZF, which has been setting the pace in the fi eld of driveline and chassis technol-ogy for years and is a reliable partner to vehicle manufacturers when it comes to making driving more responsive,safer, and more effi cient.These days, car transmissions are the true jacks-of-all-trades, backing up high-torque engines, improving fuel economy, and using fewer natural resources, while also contributing to a more dynamic and more comfortable drive. And they have to achieve all of this with-out taking up too much installation space in a wide range of vehicle models. ZF transmis-sions live up to these expectations and also set new standards. Every new generation of automatic transmissions reduces fuel consumption by between three and six percent. Andwhat’s more, they can also boast other features such as direct engine integration, sporti-2 Mechatronics module: sensing yourwishes through the soles of your feet The mechatronics module unites the elec-tronic transmission control unit and the hydraulic shifting device as a single unit within the transmission. The electronic trans-mission control unit uses data relating to the driving conditions and behavior collected by sensors to ascertain when the driver would like to shift gears, which gear they need, and when would be the best moment to do so. The hydraulic shifting device is then respon-sible for implementing those changes.1 Second-generation 6HP 6-speed automatic transmission: faster than human perception The second-generation 6-speed automatic trans-mission is undoubtedly a fast transmission and is designed for torques of up to 850 Newton meters. At the heart of the transmission are the turbine-based torsional dampers for gasoline engines and a dual damper converter for diesel engines. They are able to bridge the converter slip period much quicker and therefore result in more direct engine integration for greater respon-siveness and optimized fuel consumption. Incontrast to the predecessors, the gasoline engine reduces fuel consumption by three percent while the diesel engine saves six percent. A hydraulics system and control software now make it possible to downshift multiple times without any loss of time and also reduce reaction times by 50 percent to below the threshold of human perception.12 38HP 8-speed automatic transmission: designed for reduced fuel consumption Increased performance with lower fuel con-sumption: these seemingly contradictory exclusive targets have been achieved in ZF’s newly developed 8-speed automatic trans-mission. This has been made possible by a new transmission concept comprising four planetary gear sets and fi ve transmission 3clutches. And only two transmission clutchesare unlocked per gear, thus resulting in great-er effi ciency and a higher overall transmission ratio. Thanks to its harmonious torque and speed distribution, the 8-speed automatic transmission doesn’t take up any more space than and does not consist of any more com-ponents than the latest 6-speed automatic transmission, but will nevertheless reduce fuel consumption by six percent! This is also partly attributable to an early torque converter lockup, which is in turn also responsible for much more direct vehicle reactions when the driver pulls away. The 8-speed automatic transmission can also serve as a modular sys-tem for other initial acceleration, all-wheel drive, and hybrid concepts, without the need to adapt the basic concept.5 Dual clutch transmission: a sporty drive with low fuel consumptionWith up to 9,000 revs per minute and an effi cient transmission architecture, the dual clutch transmission really knows how to win over sporty drivers. Its winning feature comes from its two sub-transmissions: while the car drives with one of them, an electrohydraulic control system selects the next gear in the second sub-transmission. A wide array of highly effi cient transmission options reduces fuel consumption and emissions. A sponta-neous gear shift and an initial acceleration element that can be tuned to any type of engine round out the dual clutch transmis-sion’s sporty profi le.6 6-speed manual transmission: powerful and comfortableThe 6-speed manual transmission was de-signed with powerful engines in mind and is able to transfer 600 Newton meters, making it more than suitable for modern diesel en-gines. Its top performance comes from its large range of gear ratios and fi ne gear inter-vals. The 6-speed manual transmission is particularly comfortable to use thanks to a precisely defi ned pressure point. What’s more, the oil does not need replacing at any point throughout the transmission’s lifespan.7 eTronic automated transmission: economical and comfortableThe eTronic 6-speed automated transmission was designed for use in vans and minivans. It has a torque of between 350 and 500 Newton meters and helps save costs in the delivery business, as it takes care of choosing the gears and using the clutch and gearshift on behalf of the driver. The complex gear shifting strategy automatically chooses the most suit-able gear, regardless of the driver, the vehicle load, and the road. The driver nonetheless has the option of switching from automatic to manual and can then change gears using a touch control lever. Clutch operation remains automatic, thus eliminating any incorrect gear shifts that cause considerable wear.5674 8-speed hybrid transmission: for twicethe savings in the futureThe new 8-speed automatic transmission has a modular design that will allow it to be used in tandem with various drivelines without having to adapt the basic transmis-sion concept. It is particularly versatile when it comes to hybrids: a mild hybrid drive can be adapted with the addition of a crankshaft starter generator (a) or a full hybrid system can be integrated as a parallel hybrid drive (b) – both options regardless of the available space. Alternatively, the 8-speed automatic transmission can be combined with a hydrodynamic cooled clutch (c) or an integrated starting clutch (d). In terms of power take-off, it can be used with all stand- ard ZF all-wheel systems.dGenerating the necessary power for a car’s driveline is one thing – effi ciently transferring the engine power to the wheels is quite another. Depending on the driveline concept in question, the power is transferred between the engine and the drive wheels in different ways. ZF optimizes these channels with the help of innovative driveline technology such as dual damper converters, dual mass fl ywheels, hybrid modules, and intelligent distribu-tion of the drive torque via the Vector Drive rear axle drive, to make sure not an iota of power goes to waste. ZF driveline components have proven themselves to be robust, resis-Extracting Every Last Iota of Power –Driveline Components from ZF1Vector Drive rear axle drive: intelligent torque distributionAs the drive torque is distributed to the left- or right-hand wheel individually, the Vector Drive rear axle drive generates an additional yaw moment. This “screwing motion” lends support to the vehicle steering and stabilizes the car during sudden swerving without having to apply any of the wheel brakes.Vector Drive therefore results in better driving1dynamics and enhanced safety. And, with its planetary construction, the rear axle drive even delivers when the engine has no traction, i.e. in cases where the driver is not accelerating, such as when descending winding mountain roads. It also prevents tire slip when moving off on all kinds of road surfaces, which reduces wear and tear and improves the vehicle’s traction.2 Power take-off unit: top performance inthe smallest of installation spaces for cars with front transverse driveThe power take-off unit transfers the torque to the rear axle in all-wheel drives with front transverse drive and transmission. It is respon-sible for delivering maximum performance in a very tight space. The two-tier model with reinforced spur and bevel gears and a special housing construction admirably meets these requirements.233 Electric motor for hybrid drives:bringing the best of both worlds together intelligentlyHybrid drives are a high-performance cross between a combustion engine and an elec-tric motor that uses less fuel and generates fewer emissions. Whereas a combustion engine needs to reach higher speeds to achieve maximum performance, an electric motor is highly effi cient, delivering maximum torque right from the start. An intelligent drive management system utilizes the ad-vantages of both engine types for maximum driving performance in any situation, com-bined with reduced fuel consumption and emissions.7Shifttronic gearshift system: gear selection made easyThe gearshift is connected to the transmis-sion electronically, making it very reliable and easy to use. Another advantage of a purely electronic solution is that the gearshift commands can be combined with other electronic functions (e.g. in the chassis). A shift-by-wire solution also gives manu-facturers greater scope in designing and constructing the gearshift system.8 Aggregate mounting: driving force for a smooth rideThe aggregate mounting can be switched on or off and is highly effective at preventing engine vibrations from being passed on to the bodywork. When the vehicle is idling, an integrated pneumatic suspension is activated to improve the comfort level. When thevehicle is traveling, however, the module au-tomatically switches to hydraulic suspension, which is more suited to a dynamic driving style. The aggregate mounting therefore balances out not only low-frequency engine vibrations when idling, but also high-frequency vibrations caused during driving. The module also prevents unwanted pitching from being passed from the road surface to the vehicle via the engine-transmission unit.4 Clutch systems: reliable power transmissionModern clutch systems transfer the power in vehicles with a manual transmissionand consist of a pressure plate, a clutch disk with friction linings, a torsional damper, and a clutch release bearing with a hydraulic actuator system. They are available with clutch diameters ranging from 160 to 280 millimeters and are tailor-made for a wide variety of different vehicles. They transfer input torque of between 80 and 600 Newton meters, have a high load-bearing capacity, and are extremely reliable. What’s more, with the XTend automatic wear compensation, clutch manipulation remains comfortable for the duration of its lifespan.5 Torque converters: reduced consumption and maximum comfortTorque converters expertly counteract tor-sional vibrations to make driving vehicles with automatic transmission more dynamic and also to considerably reduce fuel con-sumption. Thanks to this torque converter trait, the transmission control unit is able to close the lockup clutch of the dual damper converter on diesel engines extremely quick-ly, thus reducing the time the vehicle is run in a consumption-heavy hydrodynamic state to a bare minimum.6 Dual mass fl ywheel: for a quieter power trainThe dual mass fl ywheel is located between the engine and the transmission in cars with a manual transmission and is responsible for transferring the engine torque to the pressure plate and the clutch disk. Its main purpose is to balance out any torsional vibrations that are passed from the engine to the power train in order to rule out any growling or rumbling noises and to increase the level of comfort for the vehicle passengers. It also helps to reduce fuel consumption, as driv-ers of diesel engines without a dual mass fl ywheel in particular tend to drive at higher revs that cause less vibrations and sound more “acoustically pleasant.”45678Solutions that Take the Strain –Axle Systems from ZFA lot is expected of car axle systems – they have to balance out potholes, washboards,and other road surface irregularities while still giving the driver a feeling of direct con-nection to the road. With such an important part to play, it’s the kinematics of the solu-tion that really count, so the axle system, damping, and other chassis components allhave to complement one another perfectly. ZF is a true technical expert when it comesto car chassis solutions and has exceptional chassis manufacturing know-how. As a result,automobile manufacturers from around the world place their trust in ZF’s complete axle1Front and rear axle systems: perfectly in tuneThe character of a car is very much depend-ent on its chassis, the individual components of which need to be perfectly in tune with one another to achieve the best possible re-sult. A single model of SUV can be fi tted with any one of up to nearly 100 different axle variations, depending on the engine size, the maximum load, and the quality of the roads1in the market for which the vehicle is being manufactured. This is because the front and rear axles determine the car’s handling, how comfortable it is, its responsiveness, and its safety standard. There are, however, other factors at work: wheel trunks, sensors, wheel suspension and guidance, cross members, stabilizers, springs and dampers all have their part to play in connecting the wheels to the bodywork too. One of the smallest – but no less important – components within the entire system are the rubber-metal components, which serve as elastokinematic connectors that highly effec-tively absorb vibrations and sound. With its expertise and experience, ZF supplies auto-mobile manufacturers with chassis compo-nents and complete axle systems that are constantly improving the dynamics, comfort, and safety of the manufacturers’ cars.2 Corner modules: individual parts workingin tandemCorner modules bring together the entire wheel suspension, i.e. wheel trunks, mount-ings, control arms, dampers, and springs, and the brake system. Special wheel guidance for off-roaders makes the vehicles suitable for rough terrains. Innovative suspension joints and rubber-metal mountings contribute to long suspension travel, which results in maxi-mum off-road traction.2Axle Systems2021A car’s wheel suspension and damping are responsible for a good level of road contact and for minimizing vibrations and noise. They increase a vehicle’s safety and infl uence its driving characteristics. ZF offers tried and tested modules in this fi eld. The Nivomat leveling system makes sure the car is driven at the right level, whatever it is transporting, making it safer to drive and reducing wear and tear. Driving is even safer with variable damping systems such as CDC. They adjust the damping power electronically within milli-seconds to the driving situation, between a hard, sporty damping feel and a soft, comfort-able one. Networking together with other units, CDC is part of an intelligent chassis that is capable of reacting to all sorts of different driving situations.235ARS Active Roll Stabilization: reduced rollWhen a vehicle takes a corner, actuators connected to hydraulic swivel motors on the stabilizer rod cause the two stabilizer halves to rotate towards each other, generating torsional torque. This helps reduce rolling on corners and can even cancel it out com-pletely when the transverse acceleration is below 0.3 g. As a result, the vehicle is easier to control and safer to drive.6 AOS Adaptive Off-road Stabilizer: greater off-road tractionAs soon as you get off the open road, a rigid stabilizer rod can be more of a hindrance than a help, especially when it results in a wheel simply hanging in the air. AOS is a robust system that allows the driver to decouple the stabilizer rod to improve wheel-to-road contact.7 SMiCA control arm: more functions, less weightNew manufacturing processes result in parts that are not only lighter, but also better.SMiCA (Sheet Metal integrated Control Arm) has an integrated suspension joint and is made without any rivets or screws, making it lighter than the average sheet metal control arm. It also takes up less space than more conventional solutions, giving designers greater scope when planning a chassis.2567Chassis ComponentsReally Feel the Drive –Steering Technology from ZF*Drivers have become accustomed to how easy steering can be. They benefi t from hydrau-lic and electric assistance which is supplied by the engine for simplifi ed steering. Today,good power-assisted steering is marked by its ability to give the driver a sense of directresponsiveness from their steering wheel: with immediate reaction and adapted steeringsupport, depending on the speed and the driving situation. Even when the steering sys-tem serves as an active control system, as with superimposed steering systems. Intelligentenergy management in power-assisted steering also contributes to reducing a vehicle’sfuel consumption and emissions.24251 Servolectric electric power steering system: greater functionality, less energy consumptionServolectric boasts a number of advantages. For a start, it only needs energy when the car is physically being steered. Depending on the vehicle type, this can cut energy consumption by up to 85 percent in comparison to hydraulic solutions, and this equates to a reduction in fuel consumption of 0.3 liters per 100 kilome-ters. It consists of a servo unit only, all other parts such as a steering valve, steering pump, oil reservoir, and high-pressure tubes havingbeen eliminated. It is consequently lighterand easier to install, while the absence of oiland hydraulics makes it absolutely mainte-nance-free. Just four basic Servolectric modelsare able to cover all vehicle classes, fromcompact cars to top-of-the-range models.And functioning completely independently ofthe vehicle’s engine, the servo unit can beeasily adapted electronically to suit any kindof vehicle.4 Active steering: driving enjoymentand safetyAn active steering system delivers a steeringratio that varies according to the driving situ-ation: it is sporty on winding roads, assistedin city traffi c, and provides added safety onthe highway. What’s more, with active steer-ing, the driver can perform sudden evasivemaneuvers more easily because the systemautomatically corrects the steering angle andstabilizes the vehicle.5 Rack-and-pinion power steering system:precision and sensitivityThe main advantages of ZF’s rack-and-pinionpower steering system are extremely highsteering precision on winding roads and asafer sense of steering at high speeds. With avariable-ratio rack-and-pinion power steeringsystem, it takes the driver just two revolutionsof the steering wheel to go from full left-handto full right-hand lock. The speed-dependentversion of this steering is known as Servotronic.145Steering Systems232 Varioserv steering pump:the economical marvelThe Varioserv adjustable vane pump plays animportant part in optimizing the energy usageof hydraulic steering systems. As their geomet-ric capacity can be adapted in accordance withthe pump speed, less oil is pumped aroundand back through the low-pressure circuit.The result is energy savings of up to 50 percentand a reduction in fuel consumption of up to0.15 liters per 100 kilometers.3 Steering column: with memorizedpersonal settingsElectrically adjustable steering columns domore than merely adjust the steering wheelto suit the driver’s preferences. An electroniccontrol device can also memorize varioussteering wheel positions so that all it takes isthe touch of a button when you get in the carto position the steering wheel exactly howyou want it.2627Innovations of Great Value.There’s no such thing as a “typical” driver. Nor is there a typical car, and the automobile market will increasingly be characterized by the wide variety of models and car types made available. But automotive development itself will continueto be characterized by certain objectives that have always been a main priority, and ZF’s innovative solutions will continue to address these objectives. Individual mobility needs to be economically viable and compatible with using natural resources sparingly: ZF products generate fewer emissions and reduce a car’s fuel consumption. After all, driving a car should also offer added emotional value with improved driving dynamics and comfort. ZF products deliver on this front, with precision steering, quick and comfortable gear changes, and effective propul-sion. At the same time, ZF systems can also cater to high standards of activeand passive passenger safety and make driving safer, either as a single unit or in tandem with other electronic control systems. It goes without saying that top quality, durability, and expert service are ZF standards.28293031Conserving ResourcesEvery liter of fuel saved not only benefi ts the bank account of drivers, but greater fuel economy also benefi ts the environment. However, in order to com-ply with future CO 2 specifications, more is required. Innovative technology and integrated networking ofZF uses innovative technology to prove that greater mobility, com-fort, and driving dynamics can indeed be coupled with lower energy consumption, and ZF products are already reducing fuel consump-tion considerably today, along with CO 2 emissions.active ZF products in passenger cars can optimize energy usage.Economical drivelinesThe latest transmissions offer top performance, com-on developing hybrid drives and is already in a posi-tion to offer the entire bandwidth from components to hybrid systems. The importance of hybrids to ZF is demonstrated by the 8-speed automatic transmis-sion generation of the future. It was designed to be able to be integrated into all hybrid systems, further reducing fuel consumption.LightweightReducing the weight of a vehicle reduces the amount of fuel the vehicle needs. The car’s weight can be reduced by using alternative materials such as aluminum and titanium as well as by employing innovative construction methods. Together, theseConserving Resourcesfort, and driving dynamics. And to keep up with the competition in terms of economy too, ZF’s engi-neers improved the energy effi cien-cy of ZF products and, as a result, fuel consumption has dropped by between eight and ten percent since 2001 with the help of the 6-speed automatic transmission. ZF is con-tinuing with this approach by devel-oping an 8-speed automatic trans-mission that will reap further fuel savings of six percent. At the same time, ZF is focusing more and moretwo approaches allow ZF to create transmission housings, chassis, and axle components that weigh less.Energy phenomenonIt takes a lot of energy to permanently keep some-thing on standby, such as the oil pumps in hydraulic steering systems. That’s not the case with the Varioserv steering pump. Because it gets the job done with less oil, it uses up to 40 percent less energy than conventional hydraulic pumps, withoutElectric motors for hybridtransmissions Automatic transmissions SMiCA control arms Servolectric powersteering systems Varioserv steering pumpsServolectric electric power steering system for reduced CO2A vehicle with Servolectric saves 0.3 liters per 100 kilometers.Assuming that 5 million Servolectric electric power steering systemshave been produced so far and that each vehicle clocks up an aver-age mileage of 10,000 kilometers a year, this equates to an annualgasoline saving of 150 million liters.With an average emission of 2.37 kilograms of CO2per liter ofgasoline, this results in a reduction in CO2emissions of around356 million kilograms a year.12%11%10%8%sacrifi cing comfort. The Servolectric power steeringsystem goes even further, cutting the steering system’senergy needs by up to 85 percent in comparison tohydraulic solutions as it only uses energy when the caris actively being steered.Conserving ResourcesExample:An upper midrange car with auto-matic transmission (rear-wheel drive)and medium engine size (3-litergasoline engine). Secondary condi-tions: MVEG driving cycle (Europeancycle for analysis of emissions andconsumption on dynamometers).29%17%13%32333435Greater Driving Dynamics and ComfortFor drivers, clocking up mileage quickly is more than merely a question of time – it is also a question of perception. With ZF transmissions such as the second-generation 6-speed automatic transmission or the dual clutch transmission, the gears are shifted so quickly that they are barely perceptible for theDriving ought to be enjoyable. But what people enjoy can be very subjective – depending on the driver and their mood, it can sometimes be the thrill of speed, and sometimes the relax-ation of a more leisurely drive that they are looking for. Driving dynamics and comfort are fl ip sides of the same coin. ZF’s products tap the full potential of drivelines and chassis.passengers. The torque converter’s fast lockup means the car drives more smoothly, even with gear changes. Intelligent gearshift electronics adapt to different driving styles, practically second-guessing the driver’s next moves through the soles of their feet, be it a zippy over-taking maneuver or simply cruising through the city.Extracting every last drop of powerFor effective, dynamic propulsion, the power generated by a car must be transferred from the en-gine via the wheels to the road without any losses caused by slippage or tire squeal, for example. The concept of the Torque Vector System goes one step further, by optimally distributing the drive torque to exactly where it is needed for the specifi cdriving situation. As all of the vehicle’s transmis-sions – automatic transmission, transfer case, front and rear axle drive – are linked electronically, the power can be distributed individually between the front and rear axle and between the different wheels on each axle.Greater Driving Dynamics and ComfortAutomatic transmissions Transfer cases Vector Drive rear axle drivesThe transverse distribution supports the steering and stabilizes the vehicle. Sporty drivers of all-wheel drives will noticeably feel this optimum power distri-bution whenever they take a corner or change lanes quickly – even if they do not accelerate. Cars with rear-wheel drive can also benefi t from this intelligent approach to distributing the drive torque.Unrestricted dynamicsZF is pushing back the boundaries of driving dynamics so that drivers can choose the way they drive to suit them, be it sportily or with greater safetyreserves. ZF engineers are already working on thenext generation of controlled chassis, making suretheir own units fi t seamlessly into the vehicle’s net-working environment, including brake and enginecontrol intervention. This is particularly importantin the case of IWD (Intelligent Wheel Dynamics), aconcept in which a central control unit for the activesteering, CDC electronic damping system, and VectorDrive rear axle drive makes corrections within thedynamic drive limits to improve the stability of thevehicle in critical situations. As a result, sudden eva-sive maneuvers, which put a great strain on vehiclestability, are easier to handle.ZF’s dynamic drive concepts do not mean youhave to drive a vehicle permanently within the limit.Instead, they increase safety and offer dynamicswherever and whenever the driver wants them.CDC electronicdamping systems Active steering systemsGreater Driving Dynamics and Comfort3637。