115-408: Air suspension is a type of vehicle suspension powered by an electric or engine-driven air pump or compressor . This compressor pumps the air into a flexible bellows , usually made from textile-reinforced rubber. Unlike hydropneumatic suspension , which offers many similar features, air suspension does not use pressurized liquid, but pressurized air. The air pressure inflates the bellows, and raises
230-436: A self-levelling suspension . In 1956 air suspension was used on EMD 's experimental Aerotrain . In the U.S., General Motors built on its World War II experience with air suspension for trucks and airplanes. It introduced air suspension as standard equipment on the new 1957 Cadillac Eldorado Brougham . An "Air Dome" assembly at each wheel included sensors to compensate for uneven road surfaces and to automatically maintain
345-434: A 'Pneumatic Spring for Vehicles'. The design consisted of a left and right air spring longitudinally channeled nearly the length of the vehicle. The channels were concaved to receive two long pneumatic cushions. Each one was closed at one end and provided with an air valve at the other end. From 1920, Frenchman George Messier provided aftermarket pneumatic suspension systems. His own 1922-1930 Messier automobiles featured
460-491: A C-notch is then bolted or welded to the vehicle frame in order to maintain structural integrity. Specifically on pickup trucks, this process is termed "notching" because a portion (notch) of the cargo bed may also be removed, along with the wheel wells, to provide maximum axle clearance. For some, it is desirable to have the vehicle so low that the frame rests on the ground when the air bags are fully deflated. Owners generally choose between having their cars 'tuck' their wheels into
575-448: A bow. Horse-drawn carriages and Ford Model T used this system, and it is still used today in larger vehicles, mainly mounted in the rear suspension. Leaf springs were the first modern suspension system, and, along with advances in the construction of roads , heralded the single greatest improvement in road transport until the advent of the automobile . The British steel springs were not well-suited for use on America 's rough roads of
690-500: A car with lower ground clearance has different aerodynamic characteristics, automakers can use active suspension technology to improve efficiency or handling. Tesla , for instance, uses "Active Air Suspension" on the Model S and Model X to lower or raise the vehicle for aerodynamics and increased range. In 2014 the new Mercedes S-Class Coupe introduced an update to Magic Body Control, called Active Curve Tilting. This new system allows
805-615: A functioning air/oil hydropneumatic suspension , incorporating the advantages of earlier air suspension concepts, but with hydraulic fluid rather than air under pressure. Citroën replaced the conventional steel springs on the rear axle of their top-of-range model, the Traction Avant 15 Hydraulique . In 1955, the Citroën DS incorporated four wheel hydropneumatic suspension. This combined a very soft, comfortable suspension, with controlled movements, for sharp handling, together with
920-463: A high-speed off-road vehicle encounters. Damping is the control of motion or oscillation, as seen with the use of hydraulic gates and valves in a vehicle's shock absorber. This may also vary, intentionally or unintentionally. Like spring rate, the optimal damping for comfort may be less, than for control. Damping controls the travel speed and resistance of the vehicle's suspension. An undamped car will oscillate up and down. With proper damping levels,
1035-791: A level high enough to maneuver over obstacles and inconsistencies on paved surfaces. These systems generally employ small, electric or engine-driven air compressors which sometimes fill an on-board air receiver tank which stores compressed air for use in the future without delay. It is important that the tank is sized for the task and can be calculated using a specific formula involving the compressor output, standard atmospheric pressure and compressed pressure. High-pressured industrial gas bottles (such as nitrogen or carbon dioxide tanks used to store shielding gases for welding) are sometimes used in more radical air suspension setups. Either of these reservoir systems may be fully adjustable, being able to adjust each wheel's air pressure individually. This allows
1150-403: A manual ride height switch allows control over the suspension by the driver. The "Loading" and "Off-Road" heights are available only at speeds typically less than 35 miles per hour (56 km/h). The "Highway" setting is not available manually; it is set when the vehicle moves at over typically 50 miles per hour (80 km/h) for over 30 seconds. Unlike a mechanical spring system (where deflection
1265-485: A mechanical spring, air suspension can adjust to different vehicle weights by increasing the pressure in the air bag, allowing vehicle height to be maintained at a particular value. Standard coaches also have a system called ferry lift, which raises the vehicle and increases its breakover angle . This system aids loading and unloading the coach on and off ferries due to their steep ramps and risk of grounding out, but can also be used on rough ground or on steep crests. Although
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#17328010539841380-508: A non-production prototype Stout Scarab that featured numerous innovations, including a four-wheel independent air suspension system. In 1950, Air Lift Company patented a rubber air spring that is inserted into a car's factory coil spring. The air spring expanded into the spaces in the coil spring, keeping the factory spring from fully compressing, and the vehicle from sagging. The air springs were also commonly used on NASCAR race cars for many years. In 1954, Frenchman Paul Magès developed
1495-651: A portion of the Disneyland Railroad (DRR) main line. The Tomorrowland train featured cars that were named for the planets while the cars of the Fantasyland train were named after various Disney characters. The modern, streamlined trains were placed in service to represent the future of rail travel in contrast to the steam-powered DRR which represented its past. Motive power for each train consisted of an integral head-end unit driven by an Oldsmobile "Rocket" V8 gasoline engine. Oldsmobile also furnished
1610-478: A small train whose locomotive is fashioned after that of the Aerotrain . On June 26, 1957, the narrow-gauge Santa Fe and Disneyland Viewliner (billed by Disneyland as "the fastest miniature train in the world") commenced operation. Two separate trains, designed and built as scale replicas of the futuristic Aerotrain , traveled a figure-eight track through parts of Tomorrowland and Fantasyland parallel to
1725-457: A smooth ride, and one chamber is used for a dynamic driving feeling. A solenoid valve located between each chamber and a separate electronic control unit oversees the control process. In addition, the basic minimum ground height of 148mm is divided into four stages: high, normal, low, and ultra-low according to the driving mode, driving speed, and driving environment. depending on the driving mode, driving speed, and driving environment. And it informs
1840-498: A spring rate close to the upper limit for that vehicle's weight. This allows the vehicle to perform properly under a heavy load, when control is limited by the inertia of the load. Riding in an empty truck meant for carrying loads can be uncomfortable for passengers, because of its high spring rate relative to the weight of the vehicle. A race car could also be described as having heavy springs, and would also be uncomfortably bumpy. However, even though we say they both have heavy springs,
1955-509: A streamlined design, the Aerotrain s failed to capture the public's imagination. Their cars, based on GM's bus designs and using an air cushioning system, were rough riding and uncomfortable. The design of the locomotive section made routine maintenance difficult and it was underpowered. Originally intended to reach speeds of up to 100 mph (161 km/h) and to travel between New York City and Chicago in 10.5 hours, modifications reduced
2070-415: A suspension "to hold the car aloft on four gas bubbles." During World War II , the U.S. developed the air suspension for heavy aircraft in order to save weight with compact construction. Air systems were also used in heavy trucks and aircraft to attain self-levelling suspension . With adjustable air pressure, the axle height was independent of vehicle load. In 1946, American William Bushnell Stout built
2185-400: A suspension system. In 1922, independent front suspension was pioneered on Lancia Lambda , and became more common in mass market cars from 1932. Today, most cars have independent suspension on all four wheels. The part on which pre-1950 springs were supported is called a dumb iron . In 2002, a new passive suspension component, the inerter , was invented by Malcolm C. Smith . This has
2300-547: A vehicle with zero sprung weight. They are then put through the same dynamic loads. The weight transfer for cornering in the front would be equal to the total unsprung front weight times the G-force times the front unsprung center of gravity height divided by the front track width. The same is true for the rear. Sprung weight transfer is the weight transferred by only the weight of the vehicle resting on its springs, and not by total vehicle weight. Calculating this requires knowing
2415-416: A vehicle's sprung mass to roll. It is expressed as torque per degree of roll of the vehicle sprung mass. It is influenced by factors including but not limited to vehicle sprung mass, track width, CG height, spring and damper rates, roll centre heights of front and rear, anti-roll bar stiffness and tire pressure/construction. The roll rate of a vehicle can, and usually, does differ front-to-rear, which allows for
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#17328010539842530-537: A wheel are less severe, if the wheel lifts when the spring reaches its unloaded shape than they are, if travel is limited by contact of suspension members (See Triumph TR3B .) Many off-road vehicles , such as desert racers, use straps called "limiting straps" to limit the suspensions' downward travel to a point within safe limits for the linkages and shock absorbers. This is necessary, since these trucks are intended to travel over very rough terrain at high speeds, and even become airborne at times. Without something to limit
2645-422: Is a component in setting the vehicle's ride height or its location in the suspension stroke. When a spring is compressed or stretched, the force it exerts, is proportional to its change in length. The spring rate or spring constant of a spring is the change in the force it exerts, divided by the change in deflection of the spring. Vehicles that carry heavy loads, will often have heavier springs to compensate for
2760-419: Is a simplified method of describing lateral load transfer distribution front to rear, and subsequently handling balance. It is the effective wheel rate, in roll, of each axle of the vehicle as a ratio of the vehicle's total roll rate. It is commonly adjusted through the use of anti-roll bars , but can also be changed through the use of different springs. Weight transfer during cornering, acceleration, or braking
2875-413: Is complex, and is determined by many factors; including, but not limited to: roll center height, spring and damper rates, anti-roll bar stiffness, and the kinematic design of suspension links. In most conventional applications, when weight is transferred through intentionally compliant elements, such as springs, dampers, and anti-roll bars, the weight transfer is said to be "elastic", while the weight which
2990-412: Is determined by the instantaneous front view swing arm (FVSA) length of suspension geometry, or in other words, the tendency of the tire to camber inward when compressed in bump. Roll center height is a product of suspension instant center heights and is a useful metric in analyzing weight transfer effects, body roll and front to rear roll stiffness distribution. Conventionally, roll stiffness distribution
3105-441: Is key information used in finding the force-based roll center as well. In this respect, the instant centers are more important to the handling of the vehicle, than the kinematic roll center alone, in that the ratio of geometric-to-elastic weight transfer is determined by the forces at the tires and their directions in relation to the position of their respective instant centers. Anti-dive and anti-squat are percentages that indicate
3220-518: Is largely independent of load. The developers of ECAS also designed LoadSafe, a related system to ascertain load and change in load on an LCV type vehicle fitted with air springs. The system comprises: The Multi-Chamber air suspension is a suspension capable of controlling the spring characteristics of the air suspension step by step. Multi-Chamber air suspension applicated on the Genesis G90 consists of three chambers. Three chambers are used for
3335-405: Is proportional to load), height may be varied independently from the load by altering the pressure in the air springs. The air springs were designed to provide a smooth ride, with the additional ability to raise the body of the vehicle for off-road clearance and lower it for higher-speeds road driving. Mechanical springs, for which deflection is proportional to load, cannot do this; with ECAS height
3450-428: Is sometimes eliminated and replaced with a multiple-bar linkage. These bars are typically in a trailing arm configuration and the air spring may be situated vertically between a link bar or the axle housing and a point on the vehicle's frame. In other cases, the air bag is situated on the opposite side of the axle from the main link bars on an additional cantilever member. If the main linkage bars are oriented parallel to
3565-405: Is squared because it has two effects on the wheel rate: it applies to both the force and the distance traveled. Wheel rate on independent suspension is fairly straightforward. However, special consideration must be taken with some non-independent suspension designs. Take the case of the straight axle. When viewed from the front or rear, the wheel rate can be measured by the means above. Yet, because
Air suspension - Misplaced Pages Continue
3680-410: Is the "bump-stop", which protects the suspension and the vehicle (as well as the occupants) from the violent "bottoming" of the suspension, caused when an obstruction (or a hard landing) causes suspension to run out of upward travel without fully absorbing the energy of the stroke. Without bump-stops, a vehicle that "bottoms out", will experience a very hard shock when the suspension contacts the bottom of
3795-422: Is the system of tires , tire air, springs , shock absorbers and linkages that connects a vehicle to its wheels and allows relative motion between the two. Suspension systems must support both road holding/ handling and ride quality , which are at odds with each other. The tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the road wheel in contact with
3910-412: Is transferred through more rigid suspension links, such as A-arms and toe links, is said to be "geometric". Unsprung weight transfer is calculated based on weight of the vehicle's components that are not supported by the springs. This includes tires, wheels, brakes, spindles, half the control arm's weight, and other components. These components are then (for calculation purposes) assumed to be connected to
4025-660: Is tuned adjusting antiroll bars rather than roll center height (as both tend to have a similar effect on the sprung mass), but the height of the roll center is significant when considering the amount of jacking forces experienced. Due to the fact that the wheel and tire's motion is constrained by the vehicle's suspension links, the motion of the wheel package in the front view will scribe an imaginary arc in space with an "instantaneous center" of rotation at any given point along its path. The instant center for any wheel package can be found by following imaginary lines drawn through suspension links to their intersection point. A component of
4140-486: Is usually calculated per individual wheel, and compared with the static weights for the same wheels. The total amount of weight transfer is only affected by four factors: the distance between wheel centers (wheelbase in the case of braking, or track width in the case of cornering), the height of the center of gravity, the mass of the vehicle, and the amount of acceleration experienced. The speed at which weight transfer occurs, as well as through which components it transfers,
4255-606: The Dan'l Webster the consist that the coaches and locomotives formed. The train traveled between New York City's Grand Central Terminal and Boston 's South Station from 1957 to 1958. A nearly identical train having only one locomotive ran between Cleveland and Cincinnati as the New York Central Railroad's Ohio Xplorer from 1956 to 1957. Timetables show that the Ohio Xplorer ran in 1956 during
4370-460: The Aerotrain's maximum speed to 80 mph (129 km/h). The Atchison, Topeka and Santa Fe needed a helper locomotive to enable the 1,200 horsepower LWT-12 power car to climb the Sorrento grade outside of San Diego when pulling the Aerotrain's ten coaches as a San Diegan . A Union Pacific LWT-12 later required the assistance of a 1,750 horsepower EMD GP9 switcher locomotive to transport
4485-547: The Aerotrains by coupling each of the two locomotives to sets of ten modified GM Truck & Coach Division (GMC) 40-seat intercity highway bus bodies. Designed to resemble the new PD-4501 Scenicruiser buses that GMC was building for Greyhound , the Aerotrain's passenger cars had windows with slanted sides. The finned back end of the train resembled the rear of a 1955 Chevrolet or Pontiac station wagon. Each car rode on two axles with an air suspension system that
4600-735: The Atchison, Topeka and Santa Fe Railway , where in April the train operated in California between Los Angeles and San Diego as a San Diegan . In late April, the New York Central began to operate that train in revenue service as the Great Lakes Aerotrain between Chicago and Detroit during a trial period. From July to October, the New York Central ran the train between Chicago and Cleveland while continuing
4715-454: The De Dion tube , which is sometimes called "semi-independent". Like true independent rear suspension, this employs two universal joints , or their equivalent from the centre of the differential to each wheel. But the wheels cannot entirely rise and fall independently of each other; they are tied by a yoke that goes around the differential, below and behind it. This method has had little use in
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4830-648: The Jet Rocket's Talgo-like coaches had one axle , whereas the Aerotrain's coaches had two. After less than two years, the Rock Island shortened the Jet Rocket's route. The train then traveled only between Chicago and Joliet, as did the railroad's two Aerotrains . The railroad scrapped the train several years later. GM's "lightweight with a heavyweight future" was introduced at a time when passenger train revenues were declining due to competition from airlines and private automobiles. Although they featured
4945-568: The Landau . By the middle of the 19th century, elliptical springs might additionally start to be used on carriages. Automobiles were initially developed as self-propelled versions of horse-drawn vehicles. However, horse-drawn vehicles had been designed for relatively slow speeds, and their suspension was not well suited to the higher speeds permitted by the internal combustion engine. The first workable spring-suspension required advanced metallurgical knowledge and skill, and only became possible with
5060-571: The Mercedes-Benz W112 platform featured an air suspension on the 300SE models. The system used a Bosch main valve with two axle valves on the front and one on the rear. These controlled a cone-shaped air spring on each wheel axle. The system maintained a constant ride height utilizing an air reservoir that was filled by a single-cylinder air compressor powered by the engine. In 1964, the Mercedes-Benz 600 used larger air springs and
5175-731: The New York Central Railroad . In late February 1956, the Pennsylvania Railroad rented the first train from GM and began operating it between New York City and Pittsburgh as the Pennsy (No. 1000). In June, the Pennsylvania reduced its Aerotrain's route, whereupon the trainset traveled only between Philadelphia and Pittsburgh. After the second train’s initial test run on January 5, General Motors demonstrated it on several railroads, including
5290-801: The Oregon Zoo in Portland , is a 5/8-scale replica of the Aerotrain . The Zooliner entered service in 1958. On June 14, 2008, the zoo held a "50th Birthday" celebration for the locomotive. The Zooliner remains the primary train for the zoo. Train-X was a lightweight set of nine short all-aluminum coaches articulated together that Pullman-Standard built and that two 1,000–horsepower Baldwin RP-210 diesel-hydraulic locomotives (one on each end) transported. The New York, New Haven and Hartford Railroad (the New Haven Railroad) operated as
5405-594: The Range Rover P38A . It was developed in the early 1990s by the company now known as Dunlop Systems and Components Ltd in Coventry, UK. ECAS provides variable-height suspension for on- and off-road applications. The five suspension heights typically offered by ECAS are (from lowest to highest in terms of height) "Loading," "Highway," "Standard," "Off-Road," and "Off-Road Extended." Height is controlled automatically based on speed and undercarriage sensors, but
5520-506: The United States . Its use around 1900 was probably due to the poor quality of tires, which wore out quickly. By removing a good deal of unsprung weight , as independent rear suspensions do, it made them last longer. Rear-wheel drive vehicles today frequently use a fairly complex fully-independent, multi-link suspension to locate the rear wheels securely, while providing decent ride quality . The spring rate (or suspension rate)
5635-435: The whitewall tires . For 1959, Buick offered an optional "Air Ride" system on all models that combined "soft-rate" steel coil springs in the front with air springs in the rear. An optional air suspension system was available on the 1958 and 1959 Rambler Ambassadors , as well as on all American Motors "Cross Country" station wagon models. The "Air-Coil Ride" utilized an engine-driven compressor , reservoir, air bags within
5750-446: The A.S.L. motorcycle in 1909. This was unusual in having pneumatic suspension at front and rear - rear suspension being unusual in any form of motorcycle at that time. The suspension units were similar to the normal girder forks with the spring replaced by a telescopic air unit which could be pressurised to suit the rider. Production of the motorcycles ceased in 1914. On 22 January 1901 an American, William W. Humphreys, patented an idea -
5865-484: The Rock Island scrapped or re-used most of the trainsets' equipment, both locomotives and two pairs of coaches remain on display in museums. Meanwhile, the first EMD LWT12 locomotive (serial number 20826), began to travel on the Rock Island line between Chicago and Peoria in February 1956 when pulling the line's Jet Rocket train, which bore a strong resemblance to an Aerotrain . The Rock Island later designated
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#17328010539845980-615: The Union Pacific stopped operating the trainsets in September and October 1957. In October, 1958, General Motors sold both trainsets at a discount to the Chicago, Rock Island and Pacific Railroad (the Rock Island line), which designated their locomotives as numbers 2 and 3 while using both trainsets in commuter service between Chicago and Joliet . The two trainsets ended service in 1966, ten years after they first ran. Although
6095-502: The ability to increase the effective inertia of wheel suspension using a geared flywheel, but without adding significant mass. It was initially employed in Formula One in secrecy, but has since spread to wider motorsport. For front-wheel drive cars , rear suspension has few constraints, and a variety of beam axles and independent suspensions are used. For rear-wheel drive cars , rear suspension has many constraints, and
6210-414: The actual spring rates for a 2,000 lb (910 kg) racecar and a 10,000 lb (4,500 kg) truck are very different. A luxury car, taxi, or passenger bus would be described as having soft springs, for the comfort of their passengers or driver. Vehicles with worn-out or damaged springs ride lower to the ground, which reduces the overall amount of compression available to the suspension, and increases
6325-483: The additional weight that would otherwise collapse a vehicle to the bottom of its travel (stroke). Heavier springs are also used in performance applications, where the loading conditions experienced are more significant. Springs that are too hard or too soft cause the suspension to become ineffective – mostly because they fail to properly isolate the vehicle from the road. Vehicles that commonly experience suspension loads heavier than normal, have heavy or hard springs, with
6440-522: The advent of industrialisation . Obadiah Elliott registered the first patent for a spring-suspension vehicle; each wheel had two durable steel leaf springs on each side and the body of the carriage was fixed directly to the springs which were attached to the axles . Within a decade, most British horse carriages were equipped with springs; wooden springs in the case of light one-horse vehicles to avoid taxation , and steel springs in larger vehicles. These were often made of low-carbon steel and usually took
6555-410: The air bag may be caused from debris on the road . With custom applications, improper installation may cause the air bags to rub against the vehicle's frame or other surrounding parts, damaging it. The over-extension of an air spring which is not sufficiently constrained by other suspension components, such as a shock absorber, may also lead to the premature failure of an air spring through the tearing of
6670-399: The air line that transfers the air. They are screwed into the component and for the most part push-in or push-to-fit DOT line is then inserted into the fitting. Compressor failure is primarily due to leaking air springs or air struts. The compressor will burn out trying to maintain the correct air pressure in a leaking air system. Compressor burnout may also be caused by moisture from within
6785-422: The air lines, which must be routed to the air bags through the chassis of the vehicle, rub against a sharp edge of a chassis member or a moving suspension component, causing a hole to form. This mode of failure will typically take some time to occur after the initial installation of the system, as the integrity of a section of air line is compromised to the point of failure due to the rubbing and resultant abrasion of
6900-463: The air system coming into contact with its electronic parts. This is far more likely to occur with low specification compressors with insufficient duty cycle which are often purchased due to low cost. For redundancy in the system two compressors are often a better option. In Dryer failure the dryer, which functions to remove moisture from the air system, eventually becomes saturated and unable to perform that function. This causes moisture to build up in
7015-436: The amount of body lean. Performance vehicles can sometimes have spring rate requirements other than vehicle weight and load. Wheel rate is the effective spring rate when measured at the wheel, as opposed to simply measuring the spring rate alone. Wheel rate is usually equal to or considerably less than the spring rate. Commonly, springs are mounted on control arms, swing arms or some other pivoting suspension member. Consider
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#17328010539847130-431: The arches when their air suspension is fully lowered or alternatively they can choose to go for 'fitment' which in partnership with stretched tyres sees the arch itself fit in between the tyre and rim. Air suspension is also a common suspension upgrade for those who tow or haul heavy loads with their pick-up truck, SUV, van or car. Air springs, also called "air helper springs," are placed on existing suspension components on
7245-428: The car will settle back to a normal state in a minimal amount of time. Most damping in modern vehicles can be controlled by increasing or decreasing the resistance to fluid flow in the shock absorber. See dependent and independent below. Camber changes due to wheel travel, body roll and suspension system deflection or compliance. In general, a tire wears and brakes best at -1 to -2° of camber from vertical. Depending on
7360-564: The car's height. For 1958 and 1959, the system continued on the Eldorado Brougham, and was offered as an extra cost option on other Cadillacs. In 1958, Buick introduced an optional "Air-Poised Suspension" with four cylinders of air (instead of conventional coil springs) for automatic leveling, as well as a "Bootstrap" control on the dashboard to raise the car 5.5 inches (139.7 millimetres) for use on steep ramps or rutted country roads, as well as for facilitating tire changes or to clean
7475-503: The cars of the City of Las Vegas up Southern California 's Cajon Pass . Uncomfortable riding conditions associated with the Aerotrain's higher speeds later prompted the Rock Island line to restrict its two cheaply-purchased Aerotrains to low-speed commuter service in and near Chicago, retiring the trainsets in 1966, after a decade of active service with the various operators. The EMD LWT12 locomotives and two passenger cars of each of
7590-603: The chassis from the axle. Air suspension is used in place of conventional steel springs in heavy vehicle applications such as buses and trucks , and in some passenger cars. It is widely used on semi trailers and trains (primarily passenger trains ). The purpose of air suspension is to provide a smooth, constant ride quality , but in some cases is used for sports suspension. Modern electronically controlled systems in automobiles and light trucks almost always feature self-leveling along with raising and lowering functions. Although traditionally called air bags or air bellows ,
7705-540: The coil springs, and a ride-height control, but the $ 99 optional system was not popular among buyers and American Motors (AMC) discontinued it for 1960. Only Cadillac continued to offer air suspension through the 1960 model year, where it was standard equipment on the Eldorado Seville , Biarritz, and Brougham. In 1960, the Borgward P 100 was the first German car with self-levelling air suspension. In 1962,
7820-647: The company built. GM based the EMD LWT12's power components on those in the EMD SW1200 switcher . Like the SW1200, the LWT12 used the company's model EMD 567C 12-cylinder prime mover that could produce 1,200 horsepower . The power car featured a cab that mimicked an aircraft's cockpit . The locomotive 's overall design was similar to that of General Motors automobiles at the time. The company completed
7935-419: The compressed air system also powered the brake servo. Rolls-Royce incorporated self-levelling suspension on the 1965 Rolls-Royce Silver Shadow , a system built under license from Citroën . In 1975, the Mercedes-Benz 450SEL 6.9 incorporated a hydropneumatic suspension when the patents on the technology had expired. This design replaced the expensive, complex, and problematic compressed air system that
8050-577: The correct term is air spring (although these terms are also used to describe just the rubber bellows element with its end plates). On 7 January 1901 the British engineer Archibald Sharp patented a method for making a seal allowing pneumatic or hydraulic apparatus described as a "rolling mitten seal", and on 11 January 1901 he applied for a patent for the use of the device to provide air suspension on bicycles. Further developments using this 1901 seal followed. A company called Air Springs Ltd started producing
8165-495: The degree to which the front dives under braking, and the rear squats under acceleration. They can be thought of as the counterparts for braking and acceleration, as jacking forces are to cornering. The main reason for the difference is due to the different design goals between front and rear suspension, whereas suspension is usually symmetrical between the left and the right of the vehicle. The method of determining anti-dive or anti-squat depends on whether suspension linkages react to
8280-415: The development of the superior, but more expensive independent suspension layout has been difficult. Henry Ford 's Model T used a torque tube to restrain this force, for his differential was attached to the chassis by a lateral leaf spring and two narrow rods. The torque tube surrounded the true driveshaft and exerted the force to its ball joint at the extreme rear of the transmission, which
8395-528: The differential of the live axle . These springs transmit torque to the frame. Although scorned by many European car makers of the time, it was accepted by American car makers, because it was inexpensive to manufacture. Also, the dynamic defects of this design were suppressed by the enormous weight of U.S. passenger vehicles before the implementation of the Corporate Average Fuel Economy (CAFE) standard. Another Frenchman invented
8510-440: The driver of the garage control through the infotainment screen. The speed bump control, the hump control, the slope control, and the high-speed driving control functions are activated under the air suspension control. Air bag or air strut failure is usually caused by wet rust, due to old age, or moisture within the air system that damages it from the inside. Air ride suspension parts may fail because rubber dries out. Punctures to
8625-468: The example above, where the spring rate was calculated to be 500 lbs/inch (87.5 N/mm), if one were to move the wheel 1 in (2.5 cm) (without moving the car), the spring more than likely compresses a smaller amount. If the spring moved 0.75 in (19 mm), the lever arm ratio would be 0.75:1. The wheel rate is calculated by taking the square of the ratio (0.5625) times the spring rate, thus obtaining 281.25 lbs/inch (49.25 N/mm). The ratio
8740-460: The ferry lift may be installed on some buses, the Kneel Down facility is more common on public transport buses. This helps reduce the step height for easy passenger ingress. The Kneel Down facility is also used when using the built-in wheelchair ramps. Due to several advantages, air suspension has been extensively used in commercial vehicles since 1980. Suspension (vehicle) Suspension
8855-446: The flexible layers. Failure of an air spring may also result in complete immobilization of the vehicle, since the vehicle will rub against the ground or be too high to move. However, most modern automotive systems have overcome many of these problems. Air line failure is a failure of the tubing which connects the air bags or struts to the rest of the air system, and is typically DOT-approved nylon air brake line. This usually occurs when
8970-414: The form of multiple layer leaf springs. Leaf springs have been around since the early Egyptians . Ancient military engineers used leaf springs in the form of bows to power their siege engines , with little success at first. The use of leaf springs in catapults was later refined and made to work years later. Springs were not only made of metal; a sturdy tree branch could be used as a spring, such as with
9085-430: The frame or body, which is transferred to the occupants and every connector and weld on the vehicle. Factory vehicles often come with plain rubber "nubs" to absorb the worst of the forces, and insulate the shock. A desert race vehicle, which must routinely absorb far higher impact forces, might be provided with pneumatic or hydro-pneumatic bump-stops. These are essentially miniature shock absorbers (dampers) that are fixed to
9200-453: The longitudinal (driving) axis of the car, the axle housing may be constrained laterally with either a Panhard rod or Watt's linkage . In some cases, two of the link bars may be combined into a triangular shape which effectively constrains the vehicles axle laterally. Often, owners may desire to lower their vehicle to such an extent that they must cut away portions of the frame for more clearance. A reinforcement member commonly referred to as
9315-495: The material. An air line failure may also occur if a piece of road debris hits an air line and punctures or tears it, although this is unlikely to occur in normal road use. It does occur in harsh off-road conditions but it still not common if correctly installed. Air fitting failure usually occurs when they are first fitted or very rarely in use. Cheap low quality components tend to be very unreliable. Air fittings are used to connect components such as bags, valves, and solenoids to
9430-449: The need for repair. Some manipulate the sensors to set the vehicle to a particular ride height at all times by adjusting the lever ratio on the height-sensing devices, or a supplementary ECU to "fool" the system. Leaks in the system, often due to main seal wear caused by excessive duty cycle, can cause premature compressor failure. Air springs are used in bus suspensions due to a wide range of advantages over mechanical springs. Compared to
9545-474: The power car as locomotive number 1. The American Car and Foundry Company constructed the Jet Rocket 's coaches, most of which were similar, but not identical, to those of the Talgo II . The last car resembled that of the future Talgo III . Unlike the slanted sides of the windows on the Aerotrain's ten coaches, the windows on the Jet Rocket's twelve coaches had vertical sides. In addition,
9660-481: The rear or front of the vehicle in order to increase the load capacity. One of the advantages of using air suspension as a load support enhancement is the air springs can be deflated when not towing or hauling and therefore maintaining the factory ride quality. Electronic Controlled Air Suspension (ECAS) is the name of the air suspension system installed on the Range Rover Classic in 1993 and later on
9775-610: The repainted locomotives do not resemble those that the power cars bore when last serving the Rock Island line. Disneyland operated a scale version of the Aerotrain known as the Viewliner from 1957 to 1959. The Washington Park and Zoo Railway in Portland, Oregon , has operated a scale, diesel-powered replica of the Aerotrain (dubbed the Zooliner ) to transport zoo visitors since 1958. Idlewild Park in Reno, Nevada , operates
9890-411: The road surface as much as possible, because all the road or ground forces acting on the vehicle do so through the contact patches of the tires . The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different. An early form of suspension on ox -drawn carts had the platform swing on iron chains attached to
10005-457: The spring as close to the wheel as possible. Wheel rates are usually summed and compared with the sprung mass of a vehicle to create a "ride rate" and the corresponding suspension natural frequency in ride (also referred to as "heave"). This can be useful in creating a metric for suspension stiffness and travel requirements for a vehicle. Roll rate is analogous to a vehicle's ride rate, but for actions that include lateral accelerations, causing
10120-421: The spring rate and damping settings of the suspension, among other changes, for their sport/track modes. The Lincoln Mark VIII had suspension settings which were linked to the memory seat system, meaning that the car would automatically adjust the suspension to individual drivers. Most air suspension designs are height adjustable , making it easier to enter the vehicle, clear bumps, or clear rough terrain. Since
10235-472: The sprung center of gravity height is the roll moment arm length. The total sprung weight transfer is equal to the G-force times the sprung weight times the roll moment arm length divided by the effective track width. The front sprung weight transfer is calculated by multiplying the roll couple percentage times the total sprung weight transfer. The rear is the total minus the front transfer. Jacking forces are
10350-419: The sum of the vertical force components experienced by suspension links. The resultant force acts to lift the sprung mass, if the roll center is above ground, or compress it, if underground. Generally, the higher the roll center , the more jacking force is experienced. Travel is the measure of distance from the bottom of the suspension stroke (such as when the vehicle is on a jack, and the wheel hangs freely) to
10465-470: The system and can result in damaged air springs and/or a burned out compressor. The ECAS computer can, using pre-programmed criteria to detect a fault, disable the system into "Hard Fault Mode" which lowers the vehicle to the suspension bump-stops , leaving it usable with radically reduced performance until repaired. Many enthusiasts use diagnostic devices such as laptop and hand computers running specially developed software to clear spurious faults and avoid
10580-844: The term ECAS was successfully trade marked. The system was first fitted to the 1993 model year Land Rover Range Rover. In 2005 the GM Hummer H2 featured an optional rear air suspension system with a dual compressor control system from Dunlop to support tire inflation for off-road applications. Vehicle marques that have used air suspension on their models include: Audi , Acura , Bentley , BMW , Cadillac , Citroën , Ford , Genesis , Hummer , Hyundai , Jaguar , Jeep , Land Rover , Lamborghini , Lexus , Lincoln , Mercedes-Benz , Mercedes--Maybach , Porsche , Ram , Rivian , Rolls-Royce , SsanYong , Subaru , Tesla , Volkswagen , Volvo , and more. Companies such as Jaguar and Porsche have introduced systems on some of their models that change
10695-516: The time, so the Abbot-Downing Company of Concord, New Hampshire re-introduced leather strap suspension, which gave a swinging motion instead of the jolting up-and-down of spring suspension. In 1901, Mors of Paris first fitted an automobile with shock absorbers . With the advantage of a damped suspension system on his 'Mors Machine', Henri Fournier won the prestigious Paris-to-Berlin race on 20 June 1901. Fournier's superior time
10810-476: The tire and the road surface, it may hold the road best at a slightly different angle. Small changes in camber, front and rear, can be used to tune handling. Some racecars are tuned with -2 to -7° camber, depending on the type of handling desired, and tire construction. Often, too much camber will result in the decrease of braking performance due to a reduced contact patch size through excessive camber variation in suspension geometry. The amount of camber change in bump
10925-435: The tire's force vector points from the contact patch of the tire through instant center. The larger this component is, the less suspension motion will occur. Theoretically, if the resultant of the vertical load on the tire and the lateral force generated by it points directly into the instant center, the suspension links will not move. In this case, all weight transfer at that end of the vehicle will be geometric in nature. This
11040-414: The top of the suspension stroke (such as when the vehicle's wheel can no longer travel in an upward direction toward the vehicle). Bottoming or lifting a wheel can cause serious control problems, or directly cause damage. "Bottoming" can be caused by the suspension, tires, fenders, etc. running out of space to move, or the body or other components of the car hitting the road. Control problems caused by lifting
11155-536: The torque of braking and accelerating. For example, with inboard brakes and half-shaft-driven rear wheels, the suspension linkages do not react, but with outboard brakes and a swing-axle driveline, they do. Aerotrain (GM) The Aerotrain was a streamlined trainset that the General Motors (GM) Electro-Motive Division (EMD) introduced in 1955. GM originally designated the light-weight consist as Train-Y ( Pullman-Standard 's Train-X project
11270-413: The travel, the suspension bushings would take all the force, when suspension reaches "full droop", and it can even cause the coil springs to come out of their "buckets", if they are held in by compression forces only. A limiting strap is a simple strap, often from nylon of a predetermined length, that stops downward movement at a pre-set point before theoretical maximum travel is reached. The opposite of this
11385-562: The trial period, after which it returned the train to GM. In December 1956, the Union Pacific Railroad began to operate the second train between Los Angeles and Las Vegas as the City of Las Vegas (No. 1001). The Pennsy continued to run between Philadelphia and Pittsburgh until June 1957, after which time the first trainset joined the second in the Union Pacific's City of Las Vegas service. Dissatisfied with both,
11500-579: The tuning ability of a vehicle for transient and steady-state handling. The roll rate of a vehicle does not change the total amount of weight transfer on the vehicle, but shifts the speed and percentage of weight transferred on a particular axle to another axle through the vehicle chassis. Generally, the higher the roll rate on an axle of a vehicle, the faster and higher percentage the weight transfer on that axle . By 2021, some vehicles were offering dynamic roll control with ride-height adjustable air suspension and adaptive dampers. Roll couple percentage
11615-587: The two Aerotrains that GM constructed are now on display. The National Railroad Museum in Green Bay, Wisconsin , exhibits the Rock Island line's repainted Aerotrain locomotive number 2 and two of its coaches (parts of trainset number 2). The National Museum of Transportation in Kirkwood, Missouri (near St. Louis ) exhibits the Rock Island's similarly repainted Aerotrain locomotive number 3 and two coaches (parts of trainset number 1). The designs on
11730-406: The underlying principle remains the same. The metal spring (coil or leaf) is removed, and an air bag, also referred to as an air spring, is inserted or fabricated to fit in the place of the factory spring. When air pressure is supplied to the air bag, the suspension can be adjusted either up or down (lifted or lowered). For vehicles with leaf spring suspension such as pickup trucks, the leaf spring
11845-519: The user to tilt the vehicle side-to-side, front-to-back, in some instances "hit a 3-wheel" (contort the vehicle so one wheel lifts up from the ground) or even "hop" the entire vehicle into the air. When a pressure reservoir is present, the flow of air or gas is commonly controlled with pneumatic solenoid valves . This allows the user to make adjustments by simply pressing a momentary-contact electric button or switch. The installation and configuration of these systems varies for different makes and models but
11960-429: The vehicle in a location, such, that the suspension will contact the end of the piston when it nears the upward travel limit. These absorb the impact far more effectively than a solid rubber bump-stop will, essential, because a rubber bump-stop is considered a "last-ditch" emergency insulator for the occasional accidental bottoming of the suspension; it is entirely insufficient to absorb repeated and heavy bottoming, such as
12075-494: The vehicle to lean up to 2.5 degrees into a turn, similar to a tilting train . The leaning is intended to counter the effect of centrifugal force on the occupants and is available only on rear-wheel drive models. Air suspension has become popular in the custom automobile culture: street rods , trucks, cars, and even motorcycles may have air springs. They are used in these applications to provide an adjustable suspension which allows vehicles to sit extremely low, yet be able rise to
12190-453: The vehicle's sprung weight (total weight less the unsprung weight), the front and rear roll center heights, and the sprung center of gravity height (used to calculate the roll moment arm length). Calculating the front and rear sprung weight transfer will also require knowing the roll couple percentage. The roll axis is the line through the front and rear roll centers that the vehicle rolls around during cornering. The distance from this axis to
12305-403: The wheeled frame of the carriage. This system remained the basis for most suspension systems until the turn of the 19th century, although the iron chains were replaced with the use of leather straps called thoroughbraces by the 17th century. No modern automobiles have used the thoroughbrace suspension system. By approximately 1750, leaf springs began appearing on certain types of carriage, such as
12420-402: The wheels are not independent, when viewed from the side under acceleration or braking, the pivot point is at infinity (because both wheels have moved) and the spring is directly inline with the wheel contact patch. The result is often, that the effective wheel rate under cornering is different from what it is under acceleration and braking. This variation in wheel rate may be minimised by locating
12535-562: The wife of GM vice-president and EMD general manager N.C. Dezendorf, christened the first Aerotrain trainset (GM-T1) during a press preview of the train that EMD held at its plant in McCook, Illinois (mailing address: La Grange, Illinois ) near Chicago. On January 5, 1956, one Aerotrain made a test run from Washington to Newark on the Pennsylvania Railroad while the other traveled in four hours from Chicago to Detroit on
12650-668: The windscreen, doors and instrument console for each of the two 5,000 lb (2,300 kg) locomotives. The attraction operated until September 15, 1958, when construction began on the Matterhorn and Submarine Voyage ; the Disneyland Monorail System took the place of the Viewliner in June of the following year. The Zooliner , one of three trains on the Washington Park and Zoo Railway operating in
12765-533: Was 11 hours 46 minutes and 10 seconds, while the best competitor was Léonce Girardot in a Panhard with a time of 12 hours, 15 minutes, and 40 seconds. Coil springs first appeared on a production vehicle in 1906 in the Brush Runabout made by the Brush Motor Company. Today, coil springs are used in most cars. In 1920, Leyland Motors used torsion bars in
12880-490: Was already underway) before the company adopted the Aerotrain marketing name. GM's Styling Section first brought the Aerotrain's train to life, as it did for all of GM's body designs of that mid-century era. Chuck Jordan was in charge of designing the Aerotrain as chief designer of special projects. GM constructed two Aerotrains , each of which used one of the last two (serial numbers 21463 and 21464) of three experimental diesel–electric EMD LWT12 power cars that
12995-482: Was attached to the engine. A similar method like this was used in the late 1930s by Buick and by Hudson 's bathtub car in 1948, which used helical springs that could not take fore-and-aft thrust. The Hotchkiss drive , invented by Albert Hotchkiss, was the most popular rear suspension system used in American cars from the 1930s to the 1970s. The system uses longitudinal leaf springs attached both forward and behind
13110-415: Was intended to give a smooth ride, but had the opposite effect. GM returned to a concept first used at the start of the streamliner era: semi-permanently coupled trains. The cars were 40 feet long, half the length of standard designs, thereby reducing the weight by 50%. To further reduce weight, the locomotives and cars were made of aluminum , rather than steel. On August 22, 1955, Mrs. N.C. Dezendorf,
13225-611: Was still used on the 600 models until 1984. Air suspension was not included in standard production American-built cars between 1960 and 1983. In 1984, Ford Motor Company incorporated a new design as a feature on the Lincoln Continental Mark VII . In 1986, Nissan installed an airbag modification to MacPherson Struts on the Cedric and Gloria . Dunlop Systems Coventry UK were also pioneers of Electronically Controlled Air Suspension (ECAS) for off-road vehicles -
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