Historical arrangements Front-engine, front-wheel-drive layout

1 historical arrangements

1.1 mid-engine / front-wheel drive
1.2 longitudinally mounted front-engine , front-wheel drive
1.3 front-engine transversely mounted / front-wheel drive

1.3.1 front-wheel drive design characteristics
1.3.2 front-wheel drive shafts

historical arrangements

early cars using fwd layout include 1929 cord l-29, 1931 dkw f1, 1948 citroën 2cv, 1949 saab 92 , 1959 mini. in 1980s, traction , packaging advantages of layout caused many compact , mid-sized vehicle makers adopt in us. european , japanese manufacturers switched front wheel drive majority of cars in 1960s , 1970s, last change being vw, ford of europe, , general motors (vauxhall - uk , opel - germany). toyota last japanese company switch in 1980s. bmw, focussed on luxury vehicles, retained rear-wheel-drive layout in smaller cars, though mini marque fwd.

there 4 different arrangements basic layout, depending on location of engine, heaviest component of drivetrain.

mid-engine / front-wheel drive

the earliest such arrangement not technically fwd, rather mid-engine, front-wheel-drive layout (mf). engine mounted longitudinally (fore-and-aft, or north-south) behind wheels, transmission ahead of engine , differential @ front of car. engine far back, weight distribution of such cars cord l-29 not ideal; driven wheels did not carry large enough proportion of weight traction , handling. 1934 citroën traction avant solved weight distribution issue placing transmission @ front of car differential between , engine. combined car s low slung unibody design, resulted in handling remarkable era. renault recent user of format - having used on renault 4, , first generation renault 5, has since fallen out of favor since encroaches interior space.

longitudinally mounted front-engine , front-wheel drive

a 1975 alfa romeo alfasud sprint veloce using longitudinally mounted front-engine , front-wheel drive.

the 1946 panhard dyna x, designed jean-albert grégoire, had engine longitudinally in front of front wheels, transmission behind engine , differential @ rear of assembly. arrangement, used panhard until 1967, potentially had weight distribution problem analogous of cord l29 mentioned above. however, panhard s air-cooled flat twin engine light, , mounted low down low centre of gravity reducing effect. air-cooled flat twin engine of citroën 2cv mounted low, in front of front wheels, transmission behind axle line , differential between two. became quite popular; cars using layout included german ford taunus 12m , lancia flavia , fulvia. standard configuration of audi , subaru front-wheel-drive vehicles. in 1979, toyota introduced , launched first front-wheel-drive car, tercel, , had engine longitudinally mounted, unlike other front-wheel-drive cars on market @ time. arrangement continued on second-generation tercel, until 1987, third generation received new, transversely mounted engine. other front-wheel-drive toyota models, such camry, , corolla, had transversely mounted engines beginning on.

the 1966 oldsmobile toronado (along sister models cadillac eldorado , buick riviera) used novel arrangement had engine , transmission in side-by-side arrangement power being transmitted between 2 via heavy-duty chain, , specially designed intermediate driveshaft passed under engine sump. family has distinction of being highest engine capacity (8.2 l) front-wheel-drive vehicles ever built. saab 99 , “classic” saab 900 used similar arrangement. eagle premier used similar powertrain arrangement found in renault 21 , 25 – later becoming basis chrysler lh sedans produced until 2004 model year.

today, audi prominent user of mechanical layout, having used since 1950s in predecessor companies dkw , auto union, , can found in larger models a4 upward. latest evolution of format in audi s mlb platform attempts address long standing drawback of uneven weight distribution. done packaging differential in front of clutch, allowing axle line further forward in relation rear face of engine block.

front-engine transversely mounted / front-wheel drive

the 1970s giugiaro styled hatchback coupe vw scirocco based on contemporary giugiaro golf in mk1 , mk2 forms successful vw coupe 800,000 made.



the bonnet on original mini open, showing transversely mounted engine drives front wheels.

the first popular transverse engined fwd cars dkw front made 1931, had twin cylinder two-stroke engine. saab copied design on first car, 1949 saab 92.

issigonis s mini of 1959 , related cars such maxi, austin 1100/1300 , allegro had four-cylinder inline water-cooled engine transversely mounted. transmission located in sump below crankshaft, power transmitted transfer gears. other models used transmission-in-sump layout included datsun 100a (cherry) , various applications of psa-renault x-type engine such peugeot 104 , renault 14. 1955 suzuki suzulight introduced front engine transversely installed two-stroke twin-cylinder engine (using dkw technology) in city car/kei car application, based on german lloyd lp400.

dante giacosa s autobianchi primula of 1964, fiat 128 , fiat 127, put transmission on 1 side of transversely mounted engine, , doubled drivetrain put differential behind transmission, offset 1 side. hence driveshafts wheels longer on 1 side other. located weight bit in front of wheels. system dominates worldwide @ present.

front-wheel-drive vehicles tend suffer torque steer under heavy acceleration. caused differing drive shaft lengths in turn results in different incident angles @ joints of driveshaft. farther these joints articulate, less effective @ delivering torque wheels.

front-wheel drive design characteristics




















front-wheel drive shafts

in front wheel drive vehicles, drive shafts transfer drive directly differential front wheels. short inner stub shaft splined differential side gear , outer stub shaft splined front wheel hub. each stub shaft has yoke, or housing, accommodate universal joint, @ each end of connecting intermediate shaft.

universal joints let shaft keep rotating while allowing changes due suspension movement, such shaft length , horizontal angle, , shaft angle steering turns. constant-velocity universal joints used transfer power smoothly between components. inner universal can plunge or tripod type joint. tripod splined intermediate shaft , held circlip. ball, supported on needle roller bearings, fitted each post of tripod, , these slide in trunion inside yoke. caters changes in shaft length , horizontal angle. drive transferred through trunion , balls rotate shaft.

the outer universal joint allows greater angular changes not changes in shaft length. ball , cage type inner race splined intermediate shaft. outer race formed in yoke. cage retains balls in location in grooves in both races. balls transfer drive shaft hub , allow changes in horizontal angle , wide steering angle achieved. flexible rubber boot fitted each joint retains grease , keeps out dirt , moisture.

where differential not located in center line of vehicle, intermediate shaft can fitted maintain equal length drive shafts on each side. keeps drive shaft angles equal on both sides , helps prevent steering irregularities , vibration. outer end of intermediate shaft supported bearing secured transaxle case , universal joint assists alignment.

in cases longer drive shaft used on 1 side. rubber dynamic damper may fitted absorb vibrations.