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In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, from front to back. [1] [2]
This type of motor is usually used for rear-wheel drive cars, except for some Audi, SAAB, the Oldsmobile Toronado, and the 1967 Cadillac Eldorado equipped with longitudinal engines in front wheel drive. In front-wheel drive cars a transverse engine is usually used. Trucks often have longitudinal engines with rear-wheel drive.
For motorcycles, the use of a particular type depends on the drive: in the case of a chain or belt drive a transverse engine is usually used, and with shaft drives a longitudinal engine. Longitudinal engines in motorcycles do have one disadvantage: the "tipping point" of the crankshaft tilts along the entire motorcycle to a greater or lesser degree when accelerating. This is partly resolved by having other components, such as the generator and the gearbox, rotate in the opposite direction to the crankshaft.
Most larger, "premium" vehicles use the longitudinal engine orientation in combination with rear wheel drive, because powerful engines such as the inline-6 and 90° big-bore V8 are usually too long to fit in a FF transverse engine bay. By contrast most mainstream modern vehicles use front wheel drive along with a transverse engine arrangement since they are usually equipped with inline-4 or V6 engines. While both layouts can be adapted for all-wheel drive, the longitudinal engine orientation has a more balanced weight distribution leading to superior handling characteristics, but is less efficient in terms of packaging and interior space. [3]
Cars with longitudinal engines usually have a smaller minimum turning circle than those with transverse engines. This is because there is more space to the sides of the engine, allowing deeper wheel arches so the front wheels are able to turn through a greater angle.
In the late 1960s, GM divisions Oldsmobile and Cadillac had front-wheel drive models Toronado and Eldorado respectively, with a longitudinal V8 engine and an integrated automatic transmission and differential unit powering the front wheels. Honda and Toyota also offered front-wheel drive cars with longitudinal engines, namely Honda Vigor, Acura/Honda Legend/RL, and Toyota Tercel.
This is a list of typical examples of types of engines which can be placed in motor vehicles:
A V-twin engine, also called a V2 engine, is a two-cylinder piston engine where the cylinders are arranged in a V configuration and share a common crankshaft.
A straight-four engine is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft.
Personal luxury car is a North American car classification describing somewhat sporty, sophisticated mass-market coupés that emphasized comfort over performance. The North American manufacturers most often combined engineering, design, and marketing to develop upscale, distinctive "platform sharing" models that became highly profitable.
The Cadillac Eldorado is a luxury car manufactured and marketed by Cadillac from 1952 until 2002 over twelve generations.
The Oldsmobile Toronado is a personal luxury car manufactured and marketed by the Oldsmobile division of General Motors from 1966 to 1992 over four generations. The Toronado was noted for its transaxle version of GM's Turbo-Hydramatic transmission, making it the first U.S.-produced front-wheel drive automobile since the demise of the Cord 810/812 in 1937.
Front-wheel drive (FWD) is a form of engine and transmission layout used in motor vehicles, in which the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel-drive and four-wheel-drive vehicles.
In automotive design, a front-engine, front-wheel-drive (FWD) layout, or FF layout, places both the internal combustion engine and driven roadwheels at the front of the vehicle.
The Northstar engine is a family of high-performance 90° V engines produced by General Motors between 1993 and 2011. Regarded as GM's most technically complex engine, the original double overhead cam, four valve per cylinder, aluminum block/aluminum head V8 design was developed by Oldsmobile R&D, but is most associated with Cadillac's Northstar series.
The Buick V6 is an OHV V6 engine developed by the Buick division of General Motors and first introduced in 1962. The engine was originally 198 cu in (3.2 L) and was marketed as the Fireball engine. GM continued to develop and refine the 3.8 L (230 cu in) V6, eventually and commonly referred to simply as the 3800, through numerous iterations.
The Honda Legend is a series of V6-engined executive cars/mid-size luxury sedans produced by Honda since 1985 which currently serves as its flagship vehicle. It is larger than the Honda Accord. It also provided the basis for the Acura Legend, RL and RLX — the successive flagship vehicles of Honda's luxury Acura division in North America from 1986 until 2020.
The Oldsmobile V8, also referred to as the Rocket, is a series of engines that was produced by Oldsmobile from 1949 until 1990. The Rocket, along with the 1949 Cadillac V8, were the first post-war OHV crossflow cylinder head V8 engines produced by General Motors. Like all other GM divisions, Olds continued building its own V8 engine family for decades, adopting the corporate Chevrolet 350 small-block and Cadillac Northstar engine only in the 1990s. All Oldsmobile V8s were manufactured at plants in Lansing, Michigan while the engine block and cylinder heads were cast at Saginaw Metal Casting Operations.
The Oldsmobile Diesel engine is a series of V6 and V8 diesel engines produced by General Motors from 1978 to 1985. Their design was based on the Olds 350 gasoline engine architecture. A 350 cu in (5.7 L) V8 was introduced in 1978, followed by a 261 cu in (4.3 L) V8 only for the 1979 model year. In 1982, a 263 cu in (4.3 L) V6 became available for both front front-wheel drive and rear-wheel drive vehicles.
The term Cadillac V8 may refer to any of a number of V8 engines produced by the Cadillac Division of General Motors since it pioneered the first such mass-produced engine in 1914.
The General Motors E platform or E-body was the automobile platform designation used for a number of personal luxury cars produced from 1963 to 2002. Notably, early E-bodies were produced in both front wheel drive and rear wheel drive configurations, and were the first front wheel drive automobiles produced in the United States since 1937. The initial front-wheel drive E-platform power plant was referred to as the Unitized Power Package (UPP).
The firing order of an internal combustion engine is the sequence of ignition for the cylinders.
A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the direction of travel. Many modern front-wheel drive vehicles use this engine mounting configuration. Most rear-wheel drive vehicles use a longitudinal engine configuration, where the engine's crankshaft axis is parallel with the direction of travel, except for some rear-mid engine vehicles, which use a transverse engine and transaxle mounted in the rear instead of the front. Despite typically being used in light vehicles, it is not restricted to such designs and has also been used on armoured fighting vehicles to save interior space.
A motorcycle engine is an engine that powers a motorcycle. Motorcycle engines are typically two-stroke or four-stroke internal combustion engines, but other engine types, such as Wankels and electric motors, have been used.
Turbo-Hydramatic 425 was an automatic transmission developed and produced by General Motors. The THM425 was a derivative of the THM400; most parts directly interchange and some others will interchange with minor modifications. The internal parts spin the opposite direction in the THM425; the helical angle of the planetary gears is "reversed" and the one-way clutches freewheel in the opposite direction, for example. The THM425 was developed for the 1966 Oldsmobile Toronado and the 1967 Cadillac Eldorado. A lighter-duty transmission known as the THM325 replaced the THM425 in both car lines after the 1978 model year. 1979 and later longitudinal engine front-wheel drive vehicles used the THM325. The THM325 became the THM325-4L with an overdrive added in 1982, but all vehicles using this transmission switched to more-conventional transverse engine mounting in 1986. Bellhousing pattern used the 1967-90 Buick-Oldsmobile-Pontiac-Cadillac V8 pattern throughout its entire lifecycle.
A V8 engine is an eight-cylinder piston engine in which two banks of four cylinders share a common crankshaft and are arranged in a V configuration.
The Cadillac High Technology Engine was a V8 engine produced by the Cadillac division of General Motors from 1982 to 1995.
Longitudinal engine mounting An engine mounted lengthways in the chassis.
A longitudinal engine mounts the crankshaft centerline front to rear when viewed from the top.