How the Volkswagen Touareg all-wheel drive system works

How the Volkswagen Touareg all-wheel drive system works

tell me the distribution of drive axles tell a fool 50 to 50 or not I think that no because the back runs out

Pavel76 , 50×50 on the interaxle block. The rear runs out when turning?, then it’s centrifugal force, when you strart – excess torque (paddles and pushes faster than the car accelerates), the muzzle then can’t run out

Reason: Insulting forum members + insulting the administration through the feedback system. (Ban extended)

tell me the distribution of drive axles tell a fool 50/50 or not I think not because the back runs out

Paul76 , 50×50 with the interaxle block. The rear runs out when turning?, then it’s centrifugal force, with sharp strart – excessive torque (paddles and pushes faster than the car accelerates), the muzzle then can’t run out

Depending on the situation, the spread is big from 30×70 to 70×30, but when slipping the autoblock of the diff works and 50×50

Depending on the situation, the spread is big from 30×70 to 70×30, but when slipping the autoblock of the diff works and 50×50

Permanent, from 0-100 on any axle and any wheel, with a 50×50 interaxle unit is rigid. can’t tell anything about the rear ))

IMHO with EPS on, the front wheels are predominantly “more powerful”. In a turn on the ice, you stomp on the gas, the front end scrapes the throttle a little and calms down. With EPS off. With ESP off, the tail is trying to run forward in the same conditions.

Reason: Once and for all

Depending on the situation, the spread is big from 30×70 to 70×30, but when slipping the autoblock of the diff works and 50×50

Something tells me that on four wheel drive cars the distribution is 60×40 naturally 60 to the rear wheels. That’s why it junk stalls the car on corners. Everyone must have been shocked at the sharp cornering throttle when the car stalls and the flow on the right is rapidly approaching.

Depending on the situation, the spread is big from 30×70 to 70×30, but when slipping the autoblock of the diff works and 50×50

Let’s try to figure out the magic numbers 50×50, 30×70, etc. What, in fact, are we talking about? We are talking about the proportion of torque distribution between the axles. Everybody seems to know this. But something needs to be remembered and clarified, namely what is torque. Omitting the lessons of physics, we agree that so or otherwise it is a force. And here is a good time to remember Grandpa Newton, who once said that the force of action is equal to the force of counteraction. Similarly, momentum can only be applied to something that resists. Now back to the differentials and our magic numbers. 50×50 means that the symmetric (the most traditional) axle center differential is installed. The meaning of symmetry is easy to assess on the example of the axle, when turning one wheel, the other makes exactly the same number of revolutions in the opposite direction. Now 60×40 – the asymmetric differential is designed so that it divides the torque in the proportion of 60×40. For clarity, let’s assume that one was put on the axle. Then by analogy rotate one wheel by 2 revolutions, and the second will rotate in the opposite direction not by 2 (as in the symmetric), but by 3 revolutions. Thus, 60% of torque will be supplied to the 2-turn wheel and 40% to the 3-turn wheel. Let us go back to the torque. All the proposed proportions are true for the free differential under any conditions. BUT. now the most interesting thing – it does not mean that having 50×50 one can go having clutch only on one axle. And here’s why. Let’s make an experiment – we unhook one axle, the wheels are free. What torque (force) can be applied to the wheels of this axis? NONE (remember Newton), i.e. 0 (for ease of understanding, friction and inertia forces are considered zero). But we have 50×50. . Fine, but this only means that to the second axis (which is on the ground) will be applied exactly the same moment – NONE! And the truth is, the car is in place and does not move. And now let’s block the inter-axle differential. What do we get? We already know that it is impossible to apply any torque to the hanging axle, so there is zero torque on it, but to the one on the ground, because of the blockage, all 100% is applied and the car has moved. So we have 0х100. Swap the axles and we get 100×0. Put all the wheels on the ground and we have 50×50 again. So, if the diff is locked, the torque distribution is not given by the design, but by the clutch conditions and depending on this may vary from 0х100 to 100х0 with any intermediate values. Now 40×60. Why such intricacies? To affect acceleration and handling characteristics. How. Consider acceleration at 50×50. Gas to the floor, muzzle is lifted, and the ass is resting on. At the same time, of course, front wheels are unloaded (reducing the contact patch and pressure), rear wheels are loaded. If you apply some torque, the front end will be stuck. But since it is 50×50, the rear-end, capable to digest much bigger torque, will get exactly the same amount and not one newton more. It is a shame! They put for example 40×60 to solve this misunderstanding. It is all, as they say on fingers. There are much more important parameters (axle weighing, steerability). Besides, with increase of torque to the rear, the rear-driven behavior appears and vice versa. If you change these proportions dynamically (BMW), it becomes absolutely interesting. There are also Torsens, but that is another story.

About all-wheel drive systems

I have found an interesting article on spaces of Touareg club. The source, unfortunately, I do not know.

Differences in all-wheel drive systems

There is one “secret” to “4WD” cars, and if you are not a very sophisticated person, it is easy enough to get confused. Most people who are going to buy a four-wheel drive car don’t know that: almost all of the “four-wheel drive” cars you see on the streets are actually not four-wheel drive at all.

Sure, the salesmen say that the car they are selling is four-wheel drive, and the buyers believe them and buy these cars, believing sacredly that they have bought a four-wheel drive car. However, most of these cars have non-permanent all-wheel drive, the so-called “part-time” all-wheel drive, which means that driving around town, you MUST have only the rear wheels on. The literal translation of the term “part-time” means “partial time”, that is the sense is conveyed, that it is possible to switch on all-wheel drive only for a short time (!), on a slippery, wet surface. Otherwise you will damage the whole transmission. This is all due to the lack of an inter-axle differential in such systems.

There are some exceptions. Land Rover / Range Rover along with Toyota Land Cruisers have a good, lockable “full-time” all-wheel drive system. The literal translation of the term “full-time” means “full time,” meaning it conveys the sense that all-wheel drive can be kept on all the time, i.e., without restriction.

Many of the four-wheel drive systems that call themselves “full-time” systems are actually “part-time,” but automated systems. However, many people who buy such four-wheel-drive cars do not realize that if they do not go off-road, but rather drive on the asphalt, they actually have a simple rear-wheel-drive car, which in addition (due to the design features of SUVs) has worse handling characteristics, braking qualities, higher fuel consumption and less safety. Paying much more money for all this! Silly, isn’t it?

All-Wheel Drive Systems All all-wheel drive systems can be broken down into the following categories:

Group 1: Part Time The following vehicles use a “part-time” system in which the front axle MUST be disengaged if you are driving on paved roads. All-wheelers with these systems come out cheaper, off-road these systems work quite well, but if you’re not really going off-road, then buying an SUV with this system is a waste of money, because instead you get a larger, fuel-eating rear-wheel drive station wagon.

Chevy Blazer/GMC Jimmy Ford Excursion Ford Explorer Sport Trac Dodge Durango (standard) Honda Passport / Isuzu Rodeo Hyundai Galloper Infiniti QX56 Jeep Cherokee (standard – Command Trac transfer case) Jeep Wrangler Jeep Liberty (with Command Trac transfer case) Mitsubishi Montero Sport/Mitsubishi Pajero Sport Nissan Pathfinder (Terrano) Nissan Terrano II (Ford Maverick) Nissan Patrol Nissan Xterra Suzuki Vitara/Chevrolet Tracker Suzuki Jimny Kia Sportage Opel Frontera Ssangyong Musso Land Rover Defender (optional) Land Rover S1, S2, S2A, S3 Mercedes G-class (up to 1989) SsangYong Rexton (with manual transmission transmission) Toyota 4-Runner (until 1999) Toyota Land Cruiser (in basic version, especially with diesel engine, can be delivered with “part-time” transfer gearbox) UAZ

Group 2: On demand – automated Part Time On demand are systems in which the vehicle drives in rear-wheel drive mode until the rear wheels begin to slip. In this case, the system engages the front axle and transfers some of the torque to it. This means you still have a rear-wheel drive car, but once the wheels start to slip, the system starts to help you. In most cases, it’s too late. There are systems where the car is always in front-wheel drive, and when it slips, the rear axle engages. The essence of this does not change. It is believed that these are good systems for snow. It’s a low-cost way to get a four-wheel drive system, which the manufacturer may call a “full-time” system. In fact, such systems are called “On demand,” which literally means “On Demand,” i.e., the second axle is engaged as needed. Naturally, the automatics defines the moment of necessity, not the driver.

Acura SLX / Isuzu Trooper / Opel Monterey BMW X3 (XDrive system) BMW X5 since 2004 (XDrive system) Chevy Tahoe / Yukon / Suburban Chevrolet TrailBlazer Cadillac Escalade (before 2002, transfer case NV246, interestingly solved, automated part-time) GMC Yukon XL GMC Yukon Denali / GMC Envoy Ford Explorer / Mercury Mountaineer Ford Escape (no downshift) Ford Expedition/Lincoln Navigator Infinity QX-4 Infiniti FX35 Isuzu VehiCross Honda CRV Honda HRV Honda MDX Honda Element Nissan X-Trail (constantly engaged front axle, Jeep Grand Cherokee/ZJ (Since ’96, with Quadra Trac transfer case, only 5% of torque is permanently connected to the front axle, i.e. Jeep Grand Cherokee/WJ (with Quadra Trac II transfer case) SsangYong Rexton (with automatic transmission)

Group 3: Urban Full Time The following vehicles have an inter-axle differential and operate all the time in true four-wheel drive mode, giving you all-wheel drive capability in urban mode. But – the connection design between the front and rear axle allows them to slip relative to each other (no inter-axle differential lock), which is generally good for city mode, but not ideal for off-road. Those who are not going to go offroad, the presence of this disadvantage should not worry. Such systems are the best option for them.

Cadillac Escalade (since 2002, NV149 transfer case, no downshift) Daihatsu Terios (no downshift) Dodge Durango (with Selec Trac transfer case) Ford Explorer / Mountaineer (optional) Hyundai Santa Fe (60:40 asymmetrical differential, blocked by a viscous clutch) Oldsmobile Bravado (has an inter-axle differential lock but no downshift in the transfer case, ie. not suitable for heavy off-roading) Land Rover Freelander Land Rover Discovery II Toyota RAV4 BMW X5 pre-2004 (full-time, but no downshift) Jeep Grand Cherokee/ZJ (Pre ’96, with Quadra Trac transfer case, full-time transfer case with downshift, but does not have full inter-axle differential lock – only partial, with viscocoupler) Jeep Grand Cherokee/WK (equipped with NV140 transfer case – no downshift) Mitsubishi Galant/Legnum/Aspire (4WD)

Group 4: Full Time, on- and off-road The following vehicles have a true full-time system and, just as importantly, an inter-axle differential lock, which means that these vehicles are ACTUALLY designed to operate in permanent all-wheel drive mode on paved roads and have excellent off-road performance as well. This is the most ideal set, it can be done structurally in different ways, worse or better. Unfortunately, and more expensive.

Land Rover Stage-1 (1979-1985) Land Rover Discovery Land Rover Defender Range Rover Toyota / Lexus Land Cruiser Toyota Prado Toyota 4- Runner (from 1999 and optional) Toyota Sequoia Mitsubishi Montero/Pajero Mitsubishi Pajero iO Jeep Cherokee (with Selec Trac transfer case) Jeep Liberty (with Selec Trac transfer case) Jeep Grand Cherokee (ZJ) (with Selec Trac transfer case) Jeep Grand Cherokee (WJ) (with Selec Trac transfer case) Jeep Grand Cherokee/WK (equipped with NV245 transfer case) Mercedes G- class (since 1989) Mercedes ML-320 (electronic lockup, electronic locking, but the design of the body is not for off-road) Lada Niva Hummer Volkswagen Touareg