Even at the very beginning of its history, Subaru made a bet on all-wheel drive versions of its models, a technology that at that time was available mainly on special vehicles. In 1972, Subaru introduced its first four-wheel-drive model, the Leone Estate Van 4WD, and since then, more than half of the company's sales have come from all-wheel drive vehicles. It is also important that Subaru's symmetrical all-wheel drive was not adapted to cars with a single axle drive, but was immediately created for use on cars with four-wheel drive. As for the all-wheel drive Subaru Symmetrical All Wheel Drive with axle shafts of the same length, coupled with a longitudinally located boxer Subaru Boxer engine and a transmission shifted to the wheelbase, this arrangement allows, in addition to close to ideal weight distribution along the axes, to ensure efficient implementation of engine power and a good grip balance wheels with the road on any type of surface. That is, the optimal distribution of torque between all wheels, and hence a high level of controllability.
Torque is optimally distributed to all wheels, resulting in near-neutral steering
Symmetrical all-wheel drive confidently counteracts both the drift of the front axle and the skid of the rear
There are four types of all-wheel drive Symmetrical AWD. The first of them, VTD, is not represented on the Russian market today, but was previously used on Legacy GT models 2010-2013, Forester S-Edition of the same period, Outback with a 3.6-liter engine 2010-2014, Tribeca, WRX and WRX STI 2011–212 This system uses a planetary type center differential, which is blocked by an electronically controlled multi-plate hydraulic clutch.
The original 45:55 torque distribution is constantly monitored by Vehicle Dynamic Control and automatically adjusted according to road conditions, road profile and topography. The second system is ACT with active torque distribution. Here, through a multi-plate electronically controlled clutch, the torque, depending on the condition of the road, is dosed to the front and rear wheels up to a ratio of 60:40 in real time. On the Russian market with this type of all-wheel drive, Forester, Outback and XV models with Lineatronic transmission are presented.
For mechanical transmissions, the CDG all-wheel drive system with a self-locking differential is designed. In its design, an interaxle differential with bevel gears, blocked by a viscous coupling, is used. At the same time, under normal driving conditions, the distribution of traction between the front and rear wheels occurs in a ratio of 50:50. This system is very well suited for sports driving, so it is not surprising that it was previously used on the WRX model with a manual transmission, and today the Forester and XV models with a manual transmission are on the Russian market. The fourth type of all-wheel drive Subaru - DCCD has in its arsenal an electronically controlled active limited slip differential, and it is fully focused on sports driving enthusiasts, those who love the Subaru brand for its cars with a racing character.
It is with this type of drive that we have presented the Subaru WRX STI car. This design is a symbiosis of electronic and mechanical center differential locks that respond to changes in torque. First, a faster mechanical interlock is activated, then the electronic interlock is activated. The torque between the front and rear wheels is distributed in a ratio of 41:59, and the operation of the entire system is focused on the optimal use of maximum driving characteristics. The design of the differential provides for the possibility of "preload", that is, the mode of pre-setting its characteristics. By quickly realizing high torque, such a system strikes a good balance between sharpness and precision of control and vehicle stability. Of course, in this type of drive, a manual transmission control mode is also provided.
The low center of gravity of a compact boxer engine, symmetrical all-wheel drive with equal drive lengths and transmission variations... All this ensures excellent handling on any kind of surface.
And in conclusion, a few well-known postulates about the benefits of all-wheel drive. In this case, the symmetrical all-wheel drive Subaru Symmetrical AWD. Thanks to the fact that the torque is distributed to all four wheels, the car demonstrates stable behavior both on the turning arc on asphalt pavement and when driving on uneven roads. The advantage of an all-wheel drive car is especially noticeable when driving on winter roads. Secondly, an all-wheel drive car is more prone to neutral steering than its two-wheel drive counterparts. Thus, his driver is much less likely to go past the turn. And, of course, a four-wheel drive car, as a rule, has good acceleration dynamics: the torque transmitted to all four wheels allows you to better realize the capabilities of high-power engines.
Quick jump to sections
The world premiere of the Subaru XV crossover, created on the basis of the Subaru Impreza model, took place in 2011 and today this car has firmly established itself in the ranks of urban SUVs.
There is never too much ground clearance, especially in our conditions.
Therefore, it is worth getting acquainted with the crossover, and which has the maximum ground clearance. This is the new Subaru XV, which has a ground clearance of 220 mm. This car, like the Subaru Forester, is built on the platform of the new Impreza. It is slightly smaller than the "forester", but its ground clearance is exactly the same. Plus the mandatory all-wheel drive. It's a Subaru!
Why does a car need such an impressive distance between the road and the body? Ask those who live outside the city and every day overcome kilometers of not the best roads. Also, this question will be answered by those who live in the city, but on those streets where there is no asphalt.
Alternative option
However, ground clearance is not the only criterion when choosing a versatile vehicle. After all, if this were the case, then there simply wasn’t an alternative to an equal SUV, but there is such an alternative. Subaru XV in terms of off-road capabilities can give odds to many framers, and as for behavior on asphalt and fuel consumption, almost any comparison will be in favor of a crossover.
In order to better understand the dimensions of the Subaru XV, we present the data of the Forester. XV is 15 cm shorter and 12 cm lower, but they have almost the same wheelbase. In fact, no one will feel the difference of 5 mm in practice, and therefore the interior of the Subaru XV is almost as spacious as that of the Forester.
Specifications
- Length: 4450 mm
- Width: 1780 mm
- Height: 1615 mm
- Wheelbase: 2635 mm
- Curb weight: 1415 kg
- Ground clearance: 22 cm
- Trunk volume: 310 / 1210 liters
The difference in length is noticeable only in the volume of the trunk. If the Forester has 505 liters, then the Subaru XVI has only 310. On the other hand, for most compact five-doors it is quite a normal figure. Of course, the trunk can be quadrupled if the rear seats are folded down. For a car with all-wheel drive, there is always overall luggage with which you need to make an excursion to nature.
Yes, the backs of the rear sofa are not adjustable in terms of the angle of inclination. But the landing here is lighter than on the Forester, and this allows you to move on asphalt with more confidence. This Subaru is capable of cornering at speeds worthy of the finest luxury car brands.
The fact that the car has a ground clearance of 22 cm is absolutely not felt. And it's understandable why. The boxer engine traditionally allows you to make the center of gravity lower than other cars. Plus, permanent all-wheel drive and a very well-tuned system of exchange rate stability.
As for engines, we have Subaru XV available with two engines, both petrol. The volume of the base unit is 1600 "cubes". It has 114 hp.
But much more interesting, of course, is a two-liter engine, in which one and a half hundred autohorses. With it, acceleration from standstill to the first hundred takes 10.5 seconds, and fuel consumption in the combined cycle is less than 8 liters per 100 km. And here's what's interesting: this indicator for the version with automatic transmission is better than for a car with a 6-speed manual.
Engines:
- 1.6 liter petrol
- Power 114 hp
- Torque: 150 Nm
- Maximum speed: 179 km/h
- Acceleration time to 100 km/h: 13.1 sec
- 2 liter petrol
- Power 150 hp
- Torque: 198 Nm
- Maximum speed: 187 km/h
- Acceleration time to 100 km/h: 10.7 sec
- Average fuel consumption: 6.5 liters per 100 km
Features of the variator
The reason is simple: here, as on the new generation Forester, it’s not a classic automatic, but a Lineartronic CVT. That is, there is no gear shifting, as such, but there is constantly unrelenting traction in almost the entire rev range. There is some howling characteristic of the variator, but it is drowned in the specific pleasant sound of the boxer engine. Especially if this motor is spinning.
By the way, if desired, the variator provides the ability to shift gears in manual mode, moreover, not only with a selector, but also with paddle shifters. Although, to be honest, the CVT does a great job without the driver's prompts.
By the standards of the class, the Subaru XV has a fairly spacious interior. Especially when compared with crossover competitors. Here you immediately feel the advantage that the car is built on the basis of a passenger car. And the landing is more comfortable, and the controls are all at your fingertips.
The interior, of course, is not as elegant as that of the Forster, but the quality of the finishing materials is also at its best. Front panel made of soft plastic. The seats, although they seem ordinary, are actually very tenacious to keep the driver and passengers in corners.
Audio system, climate control, power windows - all this is already "in the database". But keyless entry to the cabin, engine start button, leather seat upholstery, rain and light sensors, as well as dual-zone climate control, rely only on the top-end configuration. In it, the place of a monochrome display will also be taken by a multi-functional color one, the same as on the Forester, with a dynamic picture and a plug-in rear view camera.
All-wheel drive system
Subaru XV is only all-wheel drive. True, the “four by four” scheme here can be different. It all depends on the engine and transmission. The most off-road, oddly enough, version with a 1.6-liter engine and a manual transmission. It has an interaxle self-locking differential and a downshift is provided. So, if you plan to take real mud baths more or less regularly, it is better to opt for this version.
Cars with a CVT have their own symmetrical all-wheel drive scheme, with active torque distribution. By default, 60% of the drive is sent to the front wheels and 40% to the rear wheels. But for better grip and better handling, this ratio can change almost instantly and very flexibly. This is precisely the reason for the feeling of confidence that every driver gets behind the wheel of a Subaru.
Mandatory for all versions of the XV is the stability control system. By the way, in all configurations, except for the most basic, Subaru XV is equipped with front side and curtain airbags. In European tests, this crossover received the highest rating - five stars. Moreover, it was this car that was named "the safest for passengers' children."
The Subaru XV is truly a versatile machine that can handle just about every challenge our vehicles face in our environment equally well. It is comfortable in the city, rulitsya chic on the highway and is not afraid of moderate off-road.
After the 4WD schemes used on Toyota were considered in some detail in previous materials, it turned out that there is still an information vacuum with other brands. Let's start with all-wheel drive cars Subaru, which many call "the most real, advanced and correct."
Mechanical boxes, by tradition, are of little interest to us. Moreover, everything is quite transparent with them - since the second half of the 90s, Subaru mechanics have had an honest all-wheel drive with three differentials (the center differential is blocked by a closed viscous coupling). Of the negative sides, it is worth mentioning an overly complicated design, resulting from the combination of a longitudinally mounted engine and the original front-wheel drive. As well as the refusal of the Subarovites from the further mass use of such an undoubtedly useful thing as a downshift. On single "sports" versions, there is also a highly advanced manual transmission with an "electronically controlled" center differential, where the driver can change the degree of its blocking on the go ...
But let's not digress. There are two main types of 4WD used in automatic transmissions currently operated by Subaru.
1. Active AWD
This option has long been installed on the vast majority of Subaru (with automatic transmission type TZ1). In fact, this "all-wheel drive" is as "honest" as Toyota's V-Flex or ATC - the same plug-in rear wheels and the same TOD (Torque on Demand) principle. There is no center differential, and the rear-wheel drive is switched on by a hydromechanical clutch in the transfer case - it goes back from ~ 10% of the force under normal conditions (if this is not attributed to internal friction in the clutch) to almost 50% in the limit state.
Although the Subar scheme has some advantages in the working algorithm over other types of plug-in 4WD. Albeit small, but the moment during A-AWD operation (unless the system is forcibly turned off) is still transmitted back constantly, and not only when the front wheels slip - this is more useful and efficient. Thanks to hydromechanics, it is possible to redistribute the force (although it is too loudly said to "redistribute" - just select a part) more accurately than in the electromechanical ATC - A-AWD is able to work out slightly both in turns and during acceleration and braking, and it will be structurally stronger. The probability of a sharp spontaneous "appearance" of the rear drive in a turn with subsequent uncontrolled "flight" has been reduced (there is such a danger for cars with a viscous coupling for connecting the rear wheels).
To improve the "all-terrain" qualities, Subaru often installs an automatic locking mechanism (viscous clutch, "cam differential" - see below about it) in the rear differential of models with A-AWD.
2. VTD AWD
The VTD (Variable Torque Distribution) scheme is used on less mass-produced versions with automatic transmissions such as TV1 (and TZ102Y, in the case of the Impreza WRX GF8) - as a rule, the most powerful in the range. Here, everything is in order with "honesty" - the four-wheel drive is really permanent, with an interaxle differential (blocked by a hydromechanical clutch). By the way, since the mid-80s, Toyota 4WD has been working on the same principle on the A241H and A540H boxes, but now, alas, it has remained only on the original rear-wheel drive models (FullTime-H or i-Four all-wheel drive).
Every VTD flyer states that "Torque is split 45/55 between the front and rear wheels." And wow, many are actually beginning to believe that they are driven forward along the track by 55% rear-wheel drive. You need to understand that these figures are an abstract indicator. When the car moves in a straight line and all wheels rotate at the same speed, the center differential, of course, does not work out, and the moment is clearly divided between the axles in half. What do 45 and 55 mean? Just gear ratios in the planetary gear set of the differential. If the front wheels are forcibly stopped completely, then the differential carrier also stops, and the gear ratio between the rear drive drive shaft and the transfer case input shaft will just be the same 55/100, that is, 55% of the torque developed by the engine will go back (the differential will work as an overdrive ). If the rear wheels freeze, then 45% of the torque will go forward through the differential carrier in the same way. Of course, the presence of blocking is not taken into account here, and indeed ... In reality, the distribution of moments is a constant floating value and is far from unambiguous.
Subaru usually attaches a fairly advanced VDC (Vehicle Dynamic Control) system to the VTD, in our opinion - a system of exchange rate stability. At the start, its component, TCS (Traction Control System), slows down the slipping wheel and slightly strangles the engine (firstly, by the ignition timing, and secondly, even by turning off part of the nozzles). Classic dynamic stabilization works on the go. Well, thanks to the ability to arbitrarily slow down any of the wheels, VDC emulates (simulates) a cross-axle differential lock. Of course, this is great, but you should not seriously rely on the capabilities of such a system - so far, none of the automakers has even managed to bring the "electronic lock" closer to traditional mechanics in terms of reliability and, most importantly, efficiency.
3. "V-Flex"
Probably worth mentioning is 4WD, which is used on small models with CVTs (like the Vivio and Pleo). Here the scheme is even simpler - a permanent front-wheel drive and a rear axle "connected" by a viscous coupling when the front wheels slip.
About the cam differential
1 - separator, 2 - guide cams,
3 - thrust bearing, 4 - differential housing, 5 - washer, 6 - hub
We have already said that in English all self-locking differentials fall under the concept of LSD, however, in our tradition, this is usually called a system with a viscous coupling. The LSD rear differential often used on Subaru is built differently - it can be called "friction, cam type". There is actually no rigid connection between the drive gear of the differential and the semi-axes, the difference in the angular velocity of rotation is provided by slipping of one semi-axis relative to the other, and the "lock" is inherent in the very principle of operation.
The separator rotates with the differential housing. The "keys" fixed on the separator can move in the transverse direction. The protrusions and cavities of the cams (let's call them that) together with the keys form a transmission of rotation, like a chain.
If the resistance on the wheels is the same, then the keys do not slip and both axle shafts rotate at the same speed. If the resistance on one wheel is noticeably greater, then the keys begin to slide along the cavities and protrusions of the corresponding cam, still trying to turn it in the direction of rotation of the separator. Unlike a planetary type differential, the speed of rotation of the second half-axle does not increase (that is, if one wheel is stationary, the second will not spin twice as fast as the differential housing).
Whether or not a car with such a differential can “drive on one wheel” is determined by the current balance between the resistance on the axle shaft, the speed of rotation of the body, the amount of force transmitted back and the friction in the key-cam pair. However, this design is certainly not "off"-road.
I wanted to add useful information about Subaru's symmetrical drive and specifically my Legas. Maybe for someone who still doubts whether or not to take this car, this information will be useful and important for making the right decision.
In those. characteristics, I indicated that the drive is permanent full and this is so, but it is also symmetrical. What does it mean?
The entire system is perfectly symmetrical about the longitudinal axis of the vehicle. Evenly distributed on all four wheels, the load provides exceptional stability during movement and maneuvering.
Any road, especially in Russia, has an uneven surface. Pits found on the asphalt, slippery areas, and just puddles when driving at high speed can cause loss of control of the car. AWD all-wheel drive avoids loss of control by controlling the grip of each of the wheels every moment. When one of the wheels slips, the car reacts to prevent skidding. Increased directional stability when driving at high speeds, the car does not "scour" on bumps or ruts.
In difficult weather conditions, the grip of the tires with the road deteriorates noticeably. A slippery road covered with freshly fallen snow is an almost insurmountable obstacle for a two-wheel drive car. If any of them gets stuck, the driver is practically doomed to seek outside help. The AWD all-wheel drive system installed in Subaru cars gives even exclusively city cars the power and off-road capability. If any of the wheels loses traction, the load is redistributed to the rest and the car continues to move.
On a freeway, overcoming even not very steep, at first glance, turns, a car with a two-wheel drive can suddenly break into a skid. This is due to the gradually and imperceptibly increasing centrifugal force acting on it during the maneuver. The perfect balance of all Subaru all-wheel drive system designs and the force that is transmitted to each wheel make it possible to perfectly follow the chosen trajectory of movement. For the first time, a city car acquires the dynamics and handling of a racing car. It was after Subaru that many other auto manufacturers began to equip their cars with all-wheel drive systems, but this company retains leadership in the quality of its developments.
The system combines a fairly low center of gravity, which is inherent in Subaru boxers, and the complete lateral symmetry of the transmission. This solution combines excellent vehicle weight distribution and perfect balance, thanks to which the AWD (All Wheel Drive) all-wheel drive provides excellent stability and excellent traction of the wheels with the road surface in absolutely any conditions. The big advantage of this system is the placement on the same line of all components: engine, transmission, rear differential and universal joint, forming a symmetrical design in a horizontal plane. This solution is very important for the ideal weight distribution of the car along the length and width, which gives a neutral balance, which ensures a more comfortable and safer driving.
In confirmation of all this, I suggest watching the video at the link below. The topic of ice in Russia is more relevant than ever. Personally, when buying a car, I made a big bet on safety, because. my family's life is important. And since we have winter for six months, then the choice was obvious in favor of all-wheel drive. Only here on Subari he is really the best. WHAT CAR DO YOU THINK WAS CLIMBING THIS SLIDE? The question will be removed at the end of the video!
https://rutube.ru/tracks/3786687.html?v=aaf61c7931770df4820410f172d4b397.
