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🥾 | Assuming an eruption of Mt. Fuji Experience driving on volcanic ash Evacuation ...


Assuming an eruption of Mt. Fuji Experience driving on volcanic ash Evacuation ...

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In addition, the 4WD car was able to drive without stopping even on slopes.

It is an experience meeting to prepare for the eruption of Mt. Fuji.Yamanashi Prefecture has an experience meeting where you can drive on the volcanic ash that has actually accumulated in the past eruptions. → Continue reading

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There are lots of news to watch in Yamanashi, such as Japan's No. XNUMX Mt. Fuji and the world's fastest linear motor car. We will closely adhere to Yamanashi and deliver news from the perspective unique to the local media of XNUMX years.

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Four-wheel drive

Four-wheel driveWhat is "Yonrinkudo"?AutomobileIt is a kind of driving method such as. There are fourWheelA method of transmitting driving force to all and using it as a driving wheel.


Four-wheel drive cars are in JapaneseFour-wheel drive vehicle(Yonrinkudosha), abbreviatedXNUMXWDIt is called (Yonku).EnglishThen it is an abbreviation for four-wheel drive4WD, Or all-wheel drive,All-wheel driveTomo)AWD,In particularEuropeThen, of the four wheels, all four wheels mean driving wheels4x4Also called (four-by-four, four-by-four).

When talking about a car with four general tires, "4WD" and "AWD" can be regarded as synonymous, but they are synonymous with cars such as trucks equipped with five or more wheels.For example, in the case of a 4-wheel drive, "5WD" is a European notation.6x4, "AWD"6x6It is expressed as.note thatAmericaOnce in Japan(English editionSince the company existed and was registered as a trademark, "4WD" tends to be avoided overseas.

In Japanese, words such as "four-wheel drive," "4x4," and "4WD" are used in modern times.Cross countryCars andSUVThere was a time when it was established as a popular name for such categories.In this case, 4WD is a distinction between vehicle types and AWD is a distinction between drive mechanisms, which is a completely different concept that cannot be compared in terms of words.


There are two main purposes for adopting four-wheel drive in automobiles.

  • To drive through rough roads such as snowy roads and muddy areas where stalling is likely to occur.
  • To transmit the powerful torque of a high-power engine to the road surface.

General passenger cars, commercial vehicles, military vehicles, civil engineering and construction machinery, etc. are the reasons for the former.Especially in Japan, there is a densely populated area in one of the most heavy snowfall areas in the world, and the snow quality is damp and heavy, so the demand for four-wheel drive is greater than in other countries.Therefore, Japanese automobile manufacturers are using four-wheel drive.sedan,andMinivan,Small car,Light passenger carIt is widely set to meet the demand for snowy areas (cold areas).On the other hand, overseas, there are few major cities in areas with heavy snowfall, the snow quality is dry and smooth, and there are many movements on flat roads.AlsoNordicHas been licensed for studded tires, and demand for four-wheel drive vehicles is limited compared to Japan.[1].

The second reason for adopting four-wheel drive, the number of cases where it is installed in high-output vehicles that emphasize sportiness is increasing in recent years.Audi QuattroAsk the world atManufacturerWill follow the currentNissan GT-R,LamborghiniThe idea is to reach each model. The "SPYKER" described below is one of the first four-wheel drive vehicles that emphasized this sportiness.

As with other drive layouts, most of the engine mounting positions are front engines, and in many cases the front axle is behind the center of gravity of the engine.[2].

Differences in characteristics depending on the presence or absence of a center differential

When the car body turns, there is a difference in rotation between the outer and inner tires, but in general automobiles, differential gears (diff,Differential) Is provided, and the engine output is distributed to two different rotation speeds to prevent the drive wheels from slipping.Two-wheel drive vehicles have one differential for the pair of left and right drive wheels, while four-wheel drive vehicles require at least two for a pair of front wheels and a pair of rear wheels.Even between the front and rear wheelsInner ring differenceTherefore, before the engine output goes to the front and rear differentials, it is necessary to absorb the rotation difference between the front and rear wheels.Center differentialSome are equipped with.In this case, one output is distributed to four different rotation speeds.Many of the four-wheel drive models of modern passenger cars are equipped with a center differential.

Although the center differential is convenient, in addition to the fact that the mechanism tends to be complicated, it is always powered.transferBecause it is directly connected to the fuel economy, fuel efficiency tends to deteriorate.For this reason, commercial vehicles that emphasize fuel efficiency and economy, and cross-country SUVs that emphasize a mechanical atmosphere and have a strong taste, can be directly connected to or disconnected from the transfer with a manual switch to drive two-wheel drive and four-wheel drive. There are many "part-time types" that switch and omit the center differential.In this method, when driving on a paved road as a four-wheel drive, one of the front and rear wheels will forcibly slip due to the difference between the inner wheels when turning.brakeI was hit by a phenomenon likeManual transmissionWhen driving at low speedengine stallSometimes.This is called the tight corner braking phenomenon.In addition, when the vehicle makes a small turn at a low speed, slippage occurs in small steps, so that the entire vehicle body may be subjected to unpleasant vibration.Since these can cause breakdowns, it is practically impossible to use four-wheel drive except on low-friction road surfaces such as snow and deep gravel roads.

General strengths and weaknesses

The advantages and disadvantages compared to two-wheel drive will be described.

Strong Points

  • The biggest advantage is traction.Specifically, the traction force is greatly improved.Especially the driving force is the grip force of the tire (with the road surface)Friction) On the road surface where slipping is likely to occur,treadThe driving force applied to the vehicle can be dispersed.Therefore, it becomes easy to escape from the stack on a rough road and to run stably.Similarly, with two-wheel drive, even with a high-power engine where the tires are likely to spin, it is possible to transmit force to the ground as long as the performance of the tires allows.
  • Engine brakeSince the braking force due to is distributed to the four wheels, the wheel lock (タ イ ヤ OfGliding) Is high, and recovery from lock is quick.
  • Compared to front-wheel drive, the load is not too biased forward by the weight of the rear drive system, and the burden on the front-wheel tires is reduced.
  • Compared to rear-wheel drive, it is generally superior in straight-line stability.
  • In the case of the torque vectoring type (described later), the cornering performance and texture are superior to those of front-wheel drive.


As the drive system is added, there are many disadvantages due to the complexity of the structure and the increase in weight.

  • Since the manufacturing cost is high, the vehicle price is also higher than that of the two-wheel drive model.
  • With weightresistanceWill increaseFuel efficiencyGet worse.
  • The degree of deterioration in fuel efficiency and the degree of weight increase are disadvantageous in terms of taxation such as eco-car tax reduction and weight tax.
  • Braking performance in braking is equal to or less than that of two-wheel drive, and the heavier weight makes it easier to extend the braking distance.
  • With a live axle with a built-in differential, the unsprung weight also increases, which tends to cause disadvantages in road surface followability and ride comfort.
  • Drive shaft,gearIs addednoiseIt is disadvantageous in terms of.
  • It is necessary to change the differential oil regularly at two places, front and back.


The first four-wheel drive vehicle1805 In americaMarylandIt is said to be a dredging ship manufactured by Nono. Wheels are attached to the ship to transport it overland from the factory that produced the dredger,Steam enginePower ofBeltI ran by telling the front and rear wheels. After thatSteam engineA four-wheel drive vehicle using was manufactured.1824 ToUnited KingdomUKMade by William Henry James inSteam carFor each of the four wheelscylinderIt was designed to absorb the rotation difference of each wheel without using a differential.

Electric motorFour-wheel drive vehicles using1900 AroundFerdinand PorscheIs made by. This car will laterIn-wheel motorCalled of each wheelHubIt had a four-wheel drive with a built-in drive motor.

gasoline engineA four-wheel drive vehicle using1902 To NetherlandsMade by the Spyker brothers ofSPYKERIs the first. This car has 3 forward speeds and 1 reverse speedト ラ ン ス ミ ッ シ ョ ンAnd the second speedtransferIt is designed to drive four wheels via a center differential, and has basically the same mechanism as a modern full-time four-wheel drive vehicle.

1903 Has four-wheel drive at Daimler GmbH, AustriaArmored carWas developed. This carArmorAnd 37 mmMachine gunEquipped withTurretIt has four gears and has four gears, a forward gear and a reverse gear. Also,Ford Model TAlso in1910 eraThe four-wheel drive kit was sold after that, and there were vehicles that were made into four-wheel drive, but this is an engine that works only for the rear wheels, which are drive wheels, rather than for improving running performance.brakeIt was to make the front wheels also act.

World War IMiddle and American car companyJeffrey Motor Company(Rambler car company name at the time) is a four-wheel driveTrackAre designed and manufactured. This is known as (Quad Truck or Jeffrey Quad, Nash Quad). Fight in europeAllied ForcesProvided toJohn PershingUnder command, used for heavy duty military applications.

JapanIn1935 Around the previous yearImperial ArmyRequested byJapanese Internal Combustion MachineDeveloped byType XNUMX small passenger car(Kurogane Shiki) has appeared. Type XNUMX small passenger carU.S. Forces Ofジ ー プJapan's first practical four-wheel drive vehicle that was developed and mass-produced prior to1936 から1944 A total of 4,775 units have been produced.Sino-Japanese war-Nomonhan case-Pacific WarWidely used for reconnaissance, messenger, and transportation.

1941 , Jeep appeared in America.German army OfCubelwagen(Two-wheel drive vehicle.1940 Appeared around)Military vehicleFrom the prototypes of each company to the specifications of the US Army,bantam(English edition)The company's plan was adopted. Bantam naturally wanted to make it in-house, but in reality most of it depends on the scale and quality of its production equipment.Willis(English edition)CompanyFordIt was ordered and manufactured by the company. Jeep can be useful as a car to drive through rough roads on the battlefieldSecond World WarProven in, through mass productionAllied ForcesWas supplied to and ran across the world. Jeep's success therefore attracted attention all over the world. Even in Japan, the Army is on the Southern FrontCatchingBring back the bantam jeep to Japan and make it with the order that "the body should not be similar"Toyota, But soon it was defeated.

After the warIn Japan, there was a growing demand for cars to drive on rough roads even in the private sector, but at the beginning, there were only options such as discontinuing military cars and making domestically produced jeep-type cars that were made similar. Still,Prewar(1930 eraFor the Japanese at that time, who only knew the (old) car, the power and technology of the jeep were to convey the technological progress of the United States.1953 New Mitsubishi Heavy Industries (→ Mitsubishi Heavy Industries →Mitsubishi Motors) Is a Willis Overland JeepPolice reserveForKnockdown productiondid. Self-developedToyota jeep (Later renamed Land Cruiser)Nissan PatrolOf the police reservebidBecause I was defeated by Mitsubishi atNational local policePioneered a path for private and private demand. The Mitsubishi Jeep will then add models developed in Japan,Defense AgencyIn addition to expanding sales channels, while achieving unique evolution1998 Was produced. "Jeep" has come to be used as a synonym for small four-wheel drive vehicles in general.

1970 eraA turning point came one after another.1967 ,Hope car Light car(At that time 360cc) Full-scale four-wheel drive vehicle with a frame "Hope star ON type 4WDWas released. This vehicle isSuzuki JimnyIt was the predecessor of "," and put a stone in the form of a four-wheel drive vehicle = a large displacement vehicle.Fuji Heavy Industries(CurrentSUBARU) Is called "a field patrol vehicle that is more comfortable than a Jeep and can be used all year round"Tohoku Electric PowerIn response to the requestSubaru ff-1 1300GTo the van,Nissan BluebirdPart-time 4WD "Subaru ff-1 1300G Van 4WD" with rear axle is manufactured.1972 ToLeone 1400 Estate Van 4WDIt was released as a passenger car and pioneered a new market of four-wheel drive.

In the UKJensen MotorsThe company preceded Subaru in 1966 with a passenger car and full-time four-wheel drive.FFHowever, due to various factors, it did not match the demand in Europe and the United States, and only about 300 units were sold.Market development in Europe and the United StatesAudi quattroWill wait.

1970 eraIn the USCounter cultureIn Japan, which was influenced byOutdoorThere was a boom,Cross countryThe car became popular. At this point, laterRVThe concept of Japanese-specific leisure vehicles has begun to form. In 1984, it was a pioneer of passenger cross-country vehicles, maintaining both easy-to-use as a passenger car while maintaining the rough road running performance as a cross-country car.Mitsubishi PajeroWas released, and four-wheel drive vehicles became familiar at once. In 1985, the third generation equipped with the world's first full-time four-wheel drive with a transverse engineMazda FamiliaAppeared[3], Always four-wheel drive technology with a center differential has begun to become common in passenger cars.

Around this time in 1980Audi quattroWith the advent of, four-wheel drive technology for high-performance sports cars has begun to spread. Until the 90'sGroup B,Group AExcept for the homologation model for competition such as, it was adopted only in a small part of Porsche Lamborghini, but after the 00s, brands that once had rear-wheel drive as their identity have also improved in performance. Models equipped with four-wheel drive as a symbol have been released one after another.

At the end of this trend, four-wheel drive grades are now being set for various vehicle models.

Four-wheel drive type and mechanism

Permanent type (narrow sense)

The most primitive four-wheel drive system, also called permanent direct drive type. A prototype four-wheel drive vehicle in the early days,Military vehicle,Agricultural vehicleFound only in part of. This method is not adopted as modern passenger car technology.

Of course, it does not have a center differential that absorbs the difference in rotation between the front and rear,transferIt is not suitable for use on normal roads or for high-speed driving because you can't choose the two-wheel drive condition even if you don't even have it, or if you have it.

In addition,Construction machineryFor example, steering the rear wheels in the opposite phase at the same steering angle as the front wheels (Four-wheel steeringHowever, there is an example of avoiding the tight corner braking phenomenon by matching the trajectories of the front and rear wheels, but in extreme casesUndersteerDue to the characteristics, it is not possible to cope with the speed improvement.

Full-time type (center differential type)

Permanent type (broadly defined), also called constant type. A differential gear called a center differential (differential gear) is placed between the drive shafts connecting the front and rear wheels to absorb the rotation difference between the front and rear wheels when turning. Since the torque is distributed properly to all the wheels at all times, it excels in stability when traveling at high speeds or in rainy weather.

The early four-wheel drive vehicles that adopted this method were simple with no differential limitation.Differential gearWas using. In that case, when one wheel starts to spin on a bad road, the driving force is hardly transmitted to the other wheels. In order to avoid this, a direct connection mechanism ((Diff lock) And those that use limited slip diff. However, these names do not have a uniform definition among manufacturers, and those that use a fluid clutch (coupling) instead of differential gear or transfer for the front and rear connections, such as the standby method described later, are generally full-time type ( It is called (in a broad sense). Even in the field of service such as maintenance, the front and rear connecting parts, whether they are gears or clutches, are sometimes called center differentials, but there is a big difference in running performance, as described later.

Incidentally,Military vehicleAnd off-road orientedCross countryCar orSUVIn part of, in order to improve running performance, not only the center diff, but also the front and rear diffs (axle diff) can be differentially limited or directly connected.


Also called a selective type.Normally, it is based on two-wheel drive, and it is a method of switching to four-wheel drive by connecting a transfer that takes out power only when necessary.This was also essential to avoid many problems such as the occurrence of tight corner braking phenomenon and deterioration of handling and fuel efficiency, and to make the vehicle usable even on paved roads.In addition, in automobile manufacturing, it still exists as a method that can be retrofitted to the original two-wheel drive vehicle to four-wheel drive.Due to its simple structure and good fuel economy when driven by two wheels, it is easy to be adopted in commercial vehicles where economic efficiency is particularly important.

Part-time vehicles do not have a center differential, and four-wheel drive does not absorb the front-rear rotation difference at all, but absorbs the rotation difference by generating a forced slip between the tire and the road surface. That is, four-wheel drive traveling is premised on a slippery bad road.

If you drive on a dry paved road with part-time four-wheel drive, the tires and road surfacefrictionThe force is so great that tire slip cannot occur, causing tight corner braking and torque circulation. The drive system may be damaged or burned out, so caution is required. Torque circulation occurs even when the front and rear tire diameters are different. It happens even if the tire size in the catalog is the same, the model name is different (tread pattern or slight difference in diameter), or the degree of wear of the tire is visible. Further, it has a very high straightness regardless of the steering angle of the steering wheel. It is important to note that the maneuverability and stability of the vehicle will be greatly impaired. It is recommended to switch between XNUMXWD and XNUMXWD at low speed with the steering in neutral, or at a stopped state. A caution plate is attached to the inside of such a vehicle type, and these facts are noted.

Assuming that it is used on rough roads, the mechanism is relatively simple and reliable, and the advantage of permanent type or center differential type differential lock state can be obtained, so it is possible to drive on harsh off-road such as sandy land, mud, rocky mountain etc.Cross country,stackIt is effective to use for recovery from Since there are few merits unless such a full-scale off-road driving is premised, there was an example of adoption in passenger cars in the past, but it is almost obsolete now.

In addition, it is also common to mechanically disconnect the driven wheels using a freehub, etc. Many vehicles have a manual hub or an AUTO freehub.Land roverLike Series IOne way clutchAs a result, there is also a system in which four-wheel drive is used only when moving forward.

Part-time 4WD is for jeep andSuzuki JimnyTraditional cross-country cars like the one are based on FR, but at least for Japanese cars, most of them currently exist.FFIs the foundation[4][5].. On the other hand, most of the original FR cars do not have a space for the front axle (there is the space for the engine), so it is difficult to use 4WD. MR layout mechanical part-time 4WD vehicle is a Japanese cabover style minivan[6]Out ofRRIt will be the form adopted by almost all cars except Sambar and Sumo.The so-called "center midship" isHonda actyOnly the old model of. For RR layoutSubaru SambarAnd its expanded typeSubaru Domingo[7]There is no other example.

Full-time/part-time compound formula

It is equipped with both a part-time switchable transfer and a full-time center differential, and can be used as a full-time or part-time type. Fuel economy in two-wheel drive, stable running by distributing the driving force by the center differential, running on bad roads with direct front and rear connections, all of which can be added.

There are differences in the differential absorption method, drive distribution method, etc.Selec truckThen, we adopted a non-differential method of changing the distribution by viscous immediately after the transmission and having a transfer.Mitsubishi Motors OfSuper select 4WDThen, a method that has a differential immediately after the transmission, and then a viscous bypass with a chain and a transfer.ToyotaIn multi-mode 4WD, the order is the same as Super Select 4WD, but it is placed without bypass.Both are full-scale cross-country vehicles equipped with a rudder frame and rigid axle, but they are used in RVs that use passenger car parts to give a passenger car taste to the ride and decoration.

It has double and triple equipment, and it has a drawback that it is heavy, but in the case of a large country cross-country vehicle, it is originally responsible for low range switching for transfer.Sub transmission(* It has a low range for running on rough roads, not for improving CVT fuel economy.)Driving performanceIt has been adopted for vehicle models that are not so disadvantageous.

On-demand type / standby type (passive type)

There are many users who are confused about switching between XNUMXWD and XNUMXWD in the part-time system, and there are not a few troubles such as breaking the car or causing a fire by running at high speed on the paved road without noticing the direct connection state. Therefore, an on-demand system was devised that does not require a switching operation and is automated. Fluid clutch (instead of center differentialFluid fitting, Simply called a coupling), usually runs on either the front or rear main drive wheel, and when there is a difference in rotation between the main drive wheel and the remaining two wheels (slave drive wheels), the drive force is also applied to the slave drive wheels. A method of automatic transmission.The function of the slave drive wheels is auxiliary, and it is not suitable for long hours or transmission of strong driving force.Since the drive is distributed after it is needed, it is also called a passive type (actually, the coupling is a wet clutch filled with high viscosity oil, so it will not be completely disengaged, and the slave drive wheels will always have some degree. The torque is applied).There is no need to disconnect the slave drive wheels, and 4WD changeover switches are rarely provided.

It is often confused with the center differential system with viscous LSD, but it shows a completely different operation in terms of long-term durability and driving force distribution, and this standby system without the center differential is mechanically simpler. With a multi-plate clutch in a sturdy cylindrical caseSilicone resinAnd the multi-plate clutch is crimped by expansion of silicon due to stirring heat generated by the difference in rotation between the front and rear wheels to limit the differentialViscous couplingIs the method of inserting into the propeller shaft in front of the rear differential. No electronic control device required, especiallyVolkswagenThe early large ones adopted by were excellent in response and effectiveness. After that, to Visco DrivePatentToraiblade (3 leaves)propeller) Expressions andDual pumpAlthough a fluid clutch of the type appeared, it was lacking in sophistication, such as poor response in general and sudden connection.

In particular, the latter standby type 4WD has a clear lag until the rear wheels are driven by slipping on a bad road, and the driving force is applied to the rear when the front slips at corners etc. It may cause great shaking and spin of the car body. Was often there. There are many situations in which there is no real merit in driving on rough roads, and it is often ridiculed that "no one is better" or "Nanchatte 4WD". At present, it is rare to be adopted in the category of ordinary cars or more, but by taking advantage of the lightness of the system while making improvements such as increasing the pressure inside the case, it is often adopted in compact cars and light cars with a displacement of less than 1500cc. ing.

In this item, it is distinguished from the center differential type full-time 4WD, but in Japan,Honda Motor Co., Ltd.(Isuzu MotorsToOEMAlmost all passenger car manufacturers refer to viscous-coupling 4WD as "full-time 4WD," except that (including the products that were supplied) used the name "real-time 4WD."In particular, Fuji Heavy Industries, which was synonymous with 4WD (currentlySUBARU)When,Mitsubishi MotorsThe implications of the fact that he followed this are great. In addition, as a commercially available base competition carSuzuki Alto Works""Daihatsu Mira The TR-XX” has been adopted and has a great track record.

Torque split type / Active torque split type / Active on demand type

It is an on-demand type developed type and has a clutch mechanism of a fluid coupling on the drive shaft of the same type, but an electronically controlled pump controls increase/decrease in clutch case oil pressure to actively control front/rear drive force distribution. Using the method to do.

While the conventional on-demand (standby) type distributes the driving force to the rear wheels after a mechanical rotation difference occurs, this is the rotation difference of each wheel, steering wheel turning angle, throttle opening, G sensor Since the vehicle driving conditions are electronically calculated to predict slippage and the vehicle is driven, it is possible to obtain driving performance and stability according to actual driving conditions. In addition, the drive control is programmed even when starting or slightly turning the steering wheel, which often contributes to handling and drivability on the pavement. Some of them allow the driver to actively select (mode switching) the tendency of automatic calculation depending on road conditions such as dry roads, rainy roads, and frozen roads.

As typical ones, Toyota's dynamic torque control, Nissan's all mode 4x4, Honda'sIntelligent control system,VTM-4, SubaruACT-4, Mitsubishi AWC, Suzuki ALL GRIP, BMW(English editionAnd so on. AlsoSweden OfHaldex Traction CompanyMade active system is highly rated,VWsystem,Volvo,Ford,GMIt is used by overseas manufacturers such as[8].

Even when switching to 2WD, most of them do not use transfer disconnection, etc., but instead switch the distribution using electronically controlled switches. Some models do not have a 2WD selector switch. In addition, released in 2019Toyota RAV4Has adopted a mechanism to prevent the deterioration of fuel efficiency in FF driving by disconnecting the propeller shaft, though it is electronically controlled.[9].

Torque vectoring type

In addition to activating front-rear driving force distribution,Yaw control differentialA sophisticated four-wheel drive system that electronically variably distributes the driving force even between the left and right wheels.

By freely and variablely controlling the front, rear, left, and right driving forces, it is possible to forcibly generate a yaw moment (turning force) during turning, which a conventional four-wheel drive system has as a physical barrier. Overcoming the weak point that the stability of driving characteristics during turning was reduced. Furthermore, it becomes possible to positively control the turning characteristics, which is the control of the accelerator amount.Traction control systemFunction or individual brake controlAnti-skid deviceBy performing comprehensive control in combination with the system, we obtained turning performance superior to that of a rear-wheel drive vehicle. Various characteristics can be given by the control program, and it is also possible to exert excellent running performance even on rough terrain traveling such as split mu road.Mitsubishi Motors OfS-AWC (Super All Wheel Control)In 2001Mitsubishi Lancer EvolutionAdopted from the popular Evo 7 of the series, it set a precedent. In Honda, the drive was made active (prior to electronic control depending on the situation) by using front and rear with a fluid joint only without center diff, and using differentials with planetary gears on the left and right.SH-AWDCalled systemlegend,AcuraAdopted in 2004. Manufacturers such as BMW and Audi have also followed and adopted the left and right active differential systems.

Power distribution type

A power source is attached to each driven wheel or front and rear axles.

Internal combustion engine

Internal combustion engineIt was prime20st centuryIt couldn't be mainstream, but it still has a long history,Ferdinand PorscheA motor-driven vehicle prototyped by1900 OfParis World ExpositionIt has been put up for sale.

Since the output becomes the driving force of the tire almost as it is, there is little energy loss, and while the power distribution of the four wheels can be freely decided, the existingdiesel engineIn the case of gasoline engines, there is a limit to miniaturization, the number of parts is large, exhaust treatment is troublesome,throttleDue to the high degree of control required for motion coordination, there were only experimentally built vehicles. HoweverElectric carIn the case of No, there is no exhaust, and since it is only necessary to extend the wiring for electric power, there is little loss and it is advantageous from the point that the room can be taken widely. Mitsubishi MotorsLancer Evolution MIEVOr, although it is an "8-wheel" drive vehicle,ElikaHas adopted this method. After that, the MIEV system was commercializedMitsubishi Outlander PHEVIn the above, the two front and rear motor drives are dynamically controlled, and the left and right rear wheel drive forces are differentially controlled.AYCControlled byS-AWCIt was equipped with a mechanism. For more information,S-AWCSee section.

With an internal combustion engine,Hill climbSuch asCompetition vehicleThere is an example of twin engine in, but in a commercial carCitroen 2CV 4x4, also known as "SaharaIs almost unique. Originally with 2CV engineTransaxleFits in the front, but another same onetrunkIt was crushed and pushed. The cooperation of the two sets is simple,throttleIs a wire,ト ラ ン ス ミ ッ シ ョ ンIs only linked by shift linkage, the other two engines are independent of each other, two main switches are provided, and it is possible to operate with only one engine. ,DesertAtRedundancyIt can be said that the design has a strong implication for securing. on the other hand,Citroen Mary 4x4 istransferSub transmissionHaving a general part time4WD.

electric motor

Electric 4WDIt is called. In addition to the drive shaft by the engine,motorThis is the method to drive the other axle. In the early days of Nissan, which was adopted as a life 4WD in terms of coste-4WDLike, lowμLow output (5) with a focus on assisting when starting on the road psAlthough it was a simple one, it is expected that hybrid vehicles equipped with powerful motors and batteries will become popular and will become standard equipment in the future as one of the main methods. ing.

Currently, the "e-4WD" system for vehicles sold in JapanAutomatic transmissionHowever, it is only necessary to control the output of the electric shaft according to the number of revolutions of the engine drive shaft or the torque applied to it.Manual transmissionCombination with is not impossible.

Motor sports

Four-wheel drive, when the technology was underdeveloped, tended to be shunned except for some, but it has been recognized as a powerful weapon in various categories since the 1980s when research and development progressed.F1,GT,LMP1Have been transferredKamui KobayashiAsserts that "racing cars are absolutely faster with four-wheel drive" because of their powerful traction, ease of setting and driving, and high degree of freedom.[10].

For this reason, when a four-wheel drive vehicle and a two-wheel drive vehicle run together, there are not a few four-wheel drive vehicles.HandicapIt is common to carry.And depending on the balance of this handicap, there are often cases where two-wheel drive gives better results.In addition, the superiority of four-wheel drive changes greatly depending on the course environment and road surface conditions, so it may not be possible to say that four-wheel drive is generally strong.

Public road race

Emphasis is placed on turning and agilityRally,Rally crossIn the 1980s, four-wheel drive became popular in the worldGroup BIt is the age of.WRCTo participate inSubaru Leone OfSafari RallyIt was first to participate in the spot, but it has become popular in the upper classAudi quattroWas due to the success of[11]..At that time, it was unreliable and intenseUndersteer, There were many scenes that exposed weaknesses such as slowing of the maximum speed due to drive loss, but all of them were overcome with the progress of technology in the 1990s.Group AIn that era, all high-end entrants adopted full-time four-wheel drive.As an exception, in the latter half of the 1990s, the two-wheel drive vehicle recorded two overall wins at the Termac event in 1999 as a result of the management side significantly relaxing the rules for two-wheel drive vehicles in order to increase entrants.[12]However, since the rules have been revised since then, the top category has been contested only for four-wheel drive until now.

On the other hand, reliable running performance is also required.Rally raid(Cross-country) was established as a category relatively late after the war.[13]From ancient times to the present, four-wheel drive vehicles are common, mainly cross-country vehicles.But in the late 1990s and late 2010sDakar Rally(Old nameParis Dakar), Two-wheel drive is given preferential treatment as a promotion measure for privateers and new manufacturers.[14]During these times, four-wheel drive vehicles had been torn many times.

Hill climbThen the history is old,SpykerIn 1906BirminghamThere is a record of winning a hill climb held by a motor club[15].. In 1932Bugatti Type 53Developed.1934, despite considerable technical difficultiesLa turbieAnd 1935Château-TerieriHe has won the hill climb.
After the war, the BritishArchie Butterworth"AJB Special" (AJB S2) produced by 1948-1951British Hill Climb ChampionshipParticipated in the war and achieved a decent good result.After Butterworth retired in an accident, the car went to the United States and was active on hill climbs throughout the 1950s, fighting many breakdowns. Ferguson in the 1960s[16]P99 appeared and won the title of the championship in 1964.Since then, four-wheel drive vehicles that have not been able to play an active part in F1 have participated in the race and have won several titles.

Circuit race

F1 World ChampionshipThen, in 1950, the above-mentioned AJB special appeared in the non-title game, which is the first record.But in just one lap in the final,CrankshaftRetired due to damage to[17].. In 1960, the above-mentioned Ferguson P99 also appeared in the non-title match.This isSterling mossDrives in heavy rain, laps behind 3rd place and records the only four-wheel drive victory in history[18][19].
In the late 1960s, due to the high power of the engine, how to earn traction became a big focus of machine design, and many four-wheel drive vehicles appeared.[20]..However, due to its immature technology, it cannot be used with terrible understeer, and there are many disadvantages such as heavy weight, poor fuel economy, no matching front tires, and low reliability.[21], Was far behind the simple two-wheel drive vehicle equipped with the rear wing.In 1968, when there were many rain conditions, it was still possible to fight, but in 1969, the disadvantages of four-wheel drive vehicles became apparent, and it disappeared after 1970 when slick tires were introduced.afterwardsWilliamsIn 1982, a four-wheel drive vehicle with a rear two-wheeled six-wheeled vehicleFW08BI tested, but I thought this would be a balance breakerFIAIn 1983, stipulated a limit on the number of tires and a ban on four-wheel drive, marking a break in history. Since the 2010s, there have been discussions about four-wheel drive using electric technology for a while, but none of them have been realized.[22][23].

IndyCarHarry Miller[24]The four-wheel drive vehicle "FWD Special" jointly developed by FWD and FWD participated sporadically in the 1930s.In the qualifying, he sometimes showed speed, but the problem of reliability was seriously hampered, and he could not leave a good record except for finishing 1936th by Mauri Rose in the 500 Indy 4.[25][26][27].. In 1964 and 1965, the Ferguson P104 was driven by the Indy 500, but was quickly retired due to a crash and breakdown. Incorporated the Ferguson system in 1968gas turbinecar'sLotus 56Has climbed to the level of one step closer to winning the Indy 500, but ended up retiring due to a breakdown, and immediately after that, it withdrew due to the tightening of gas turbine vehicle regulations and the prohibition of four-wheel drive.[28].

Sports car enduranceThen in the 1970sCan-AmThere is evidence of trial and error in power-distributed four-wheel drive vehicles[29]..For the first time, it was equipped with a "variable torque split" type four-wheel drive that was epoch-making at that time.Porsche 961so,24 Hours of Le MansIn addition to winning the class inGroup CIt is mixed with the force and is digging into 7th place.The 1988 North American Trans-Am Series and the 1989 IMSA-GTO adopted the Quattro system.Audi 90Raged[30]..However, four-wheel drive was banned in both Europe and the United States after the 90s, probably because it seemed to hinder the performance balance.
Time has passed and it started in 2012WecUnder the LMP1 regulations of (World Endurance Championship)Hybrid machineWhen four-wheel drive is approved,Audi R18,Toyota/TS050 HYBRID,Porsche 919 HYBRIDBut usuallyRear wheel driveEquipped with a standby four-wheel drive that drives the front wheels only when the motor is output, it gained popularity at a speed approaching that of an F200 machine that is 1 kg lighter. Enforced from 2021LM hypercarThe regulations also continue to approve the adoption of four-wheel drive hybrid machines.Toyota GR010 HYBRIDIs the first champion.

Touring carIn the race, in the early 1990sGroup AIn the age of racingNissan Skyline GT-RBut"Atesa ET-S』Equipped with advanced standby four-wheel drive technology, in JapanOne-make raceHe continued to win enough to build a state and push the Group A rules to the end.But it became a new battlefieldAll Japan GT ChampionshipHas a wide range of modifications, and it has become possible to earn sufficient traction even with two-wheel drive by installing thick tires and large wings, and drastically modifying the suspension. Became the mainstream[31]..After that, it entered the GT300 class as a four-wheel drive vehicle with special approval.Subaru ImprezaWon the championship in 2008, but tightened regulations[32]I am in the worries of withdrawal.
For European touring cars, based on Group A regulationsDTM(German Touring Car Championship) adopted the Quattro systemAudi V8Has won the series in 1990 and 1991 in a row, but it also encountered tightening regulations and soon withdrew.In the successor Super Touring Car Regulation "Class 1"Alfa Romeo 155 V6 TIOpel Calibra V6 4X4Was active as a four-wheel drive vehicle, but it was a two-wheel drive vehicle armed with sophisticated aerodynamic design and electronic devices.Mercedes C Class V6It ends in the same battle record as.On the other hand, in the races of European countries with "Class 2" regulations, Audi brought in the Quattro system here as well, and in 1996A4 QuattroLeft an overwhelming record of conquering Britain, Germany and Italy at the same time.After that, the A4 Quattro continued to maintain first-class combat power even when it was given a weight handicap of nearly 100 kg, but in 1998 four-wheel drive itself was banned.[33][34].
Touring car regulations currently adopted in the top category[35]In each case, if the base commercial vehicle is four-wheel drive, it is obligatory to replace it with two-wheel drive.Therefore, the four-wheel drive vehicle of the touring carSuper endurance,Nürburgring 24 hoursIt remains to the extent that it is recognized in the lower class of races with a strong amateur color.


[How to use footnotes]
  1. ^ How to choose "4WD" cultivated by Japan's climate with one of the world's most heavy snowfall areas 2016.2.22 Masayuki Moriguchi
  2. ^ Rear engine4WD ThePorsche 911,Subaru Sambar(3rd-6th generation), exists in Hufflinger of Steia Puff.AlsoMidship4WDIt is,Mitsubishi Pajero,Toyota Estima(First generation),Honda acty,Suzuki Every(3th generation),LamborghiniEach model,Bugatti Veyron,Audi R8There are examples such as
  3. ^ Japan's first full-time 2WD was Mazda! Speaking of AWD, two reasons that are likely to become Mazdacliccar January 2016, 1
  4. ^ Is a dawnSubaru LeoneHowever, the drive system of FF was extended to drive the rear wheels via transfer.Fuji Heavy Industries (currentlySUBARU) Was an affiliated company at that time because it did not produce FR cars when the first Leone 4WD was released, so it did not have the production know-how of rear axles.Nissan MotorからBluebirdHad been OEM supplied. Other companiesToyota Sprinter CaribbeanAnd so on.
  5. ^ IwanyaMitsubishi Minica(Up to the 4th generation)Suzuki Cappuccino, And is manufactured with Suzuki OEM partsCaterhamThere is only Jimny in the light car which has only FR model of FR.
  6. ^ OnceOne box carThe car type called.
  7. ^ Based on a Sambar engine with a 1000cc engine and a 3-row seat for a 7-seater passenger car. When it became 1200cc later, it became a one-way clutch type, but in the subsequent full model change it became a viscous coupling type described later.
  8. ^ What about full-time 4WD for imported cars? Do you have individuality with various controls 2017.10.03 / Entertainment Best Car Web Editor
  9. ^ What is the world's first "dynamic torque vectoring AWD" of the new Toyota RAV4
  10. ^ Kawai-chan, Ukyo-san, this is the car (TS050 HYBRID) fighting in WEC!TOYOTA GAZOO Racing Official Website Retrieved April 2021, 8
  11. ^ Both Audi and Subaru are pioneers of four-wheel drive passenger cars, but bothVertical engine-Front wheel driveSince there was a car with the structure of on the market, take out the drive shaft from the vertical gearbox to the rear.DifferentialIt was a structure that was relatively easy to drive with four wheels, as it only required processing such as adding a rear wheel drive shaft.
  12. ^ Citroen KusaraF2 kit car.In addition to lightweight chassis and thick tires, active differentials andTraction controlWith electronic devices such as, traction performance comparable to 4WD was secured
  13. ^ Before the war, Spyker finished second in the 1907 Paris-Beijing transcontinental rally.
  14. ^ Preferential items range from weight, tire size, suspension stroke, tire internal pressure adjustment system, etc.
  15. ^ Marque TimeTHE IRISH TIMES Retrieved January 2022, 1
  16. ^ laterJensen MotorsBy partnership with the companyJensen FFAnd four-wheel drivesedanHas been realized on the market
  17. ^ Archie ButterworthHr'22 January 2022, 1
  18. ^ It is also the last victory record for a front engine car.Moss loves this car and cites the P99 as a "car he wants to ride again" after retirement.
  19. ^ With Maserati following the trail of Stirling Moss, the greatest driver in British historyLivedoor News Viewed January 2022, 1
  20. ^ Especially in 1969, because the high mount wing, which had been the mainstream until then, was banned, BRM P67,Lotus 63,Matra MS84,McLaren M9AMany four-wheel drive vehicles participated in the war
  21. ^ Four wheel drive prohibited in F1Tochu F1 Express July 2010, 7
  22. ^ [F1] Discussing 1WD for F4 carsF1-Gate Retrieved August 2021, 8
  23. ^ Volkswagen wants F1 to adopt a four-wheel drive systemTop News Retrieved August 2021, 8
  24. ^ Front wheel driveIndy 500Is the only constructor driver with experience in winning
  25. ^ The car is the predecessor of F1European Drivers ChampionshipIn that sense, it is also F1's first four-wheel drive vehicle.
  26. ^ 1932 Miller FWD Special Roadster Vehicle ProfileCONCEPTCARS Retrieved January 2022, 1
  27. ^ [1]SPEEDWAY MOTORS MUSEUM OD AMERICAN SPEED Retrieved January 2022, 1
  28. ^ Equipped with a gas turbine engine for helicopters !? Approaching a unique racing car created by the timesMotorz ​​Retrieved August 2021, 8
  29. ^ Legendary ambition! The 2WD "Max It Special" with 4 4-stroke engines is amazing!Motorz ​​Retrieved August 2021, 11
  31. ^ 1994 Skyline GT-R BNR32NISMO official website viewed July 2021, 7
  32. ^ Immediately after the victory, the weight was 175kg heavier than the opening race without weight handicap.
  33. ^ "All about Sun Aimook Japan-Europe Touring Cars" July 2020, 7 from Sanei Shobo Publishing
  34. ^ In addition, Ford is also a four-wheel driveMondeoIn 1995 STW (German Super Touring Championship), But it did not go well and withdrew in one year
  35. ^ Group GT3,TCR,LM-GTE, Class 1 (DTM and GT500), NGTC (BTCC original regulation), etc.

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