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65-658: The Citroën ZX is a small family car produced by the French manufacturer Citroën between 1991 and 1998. At the beginning of the 1990s, the ZX was Citroën's entry in the class traditionally dominated in Europe by the Ford Escort and Vauxhall / Opel Astra , a market segment Citroën had briefly abandoned with the demise of the GSA in 1986. The BX had tried to address the small family car market and

130-522: A turbodiesel . However, the 1.1 petrol engine was never sold in Britain. The car won the Paris-Dakar Rally four times — in 1991 with Ari Vatanen and in 1994 , 1995 , 1996 with Pierre Lartigue , claiming a total 59 stage wins. It also won five FIA World Cup for Cross-Country Rallies titles, four by Pierre Lartigue between 1993-1996 and one by Ari Vatanen in 1997. In terms of rallycross,

195-609: A "compact car" target that was larger than what has become known as the "light car" or the kei car . One of the first compact cars that met those requirements was the Toyota Publica with an air-cooled two-cylinder opposed engine, the Datsun 110 series , and the Mitsubishi 500 . The Publica and the Mitsubishi 500 were essentially "kei cars" with engines larger than regulations permitted at

260-556: A few weeks later. New Zealand's unleaded petrol was of a low octane rating, meaning that initially only uncatalyzed cars were on offer. In January 1994, the estate of the ZX debuted, and went on sale in May, shortly thereafter followed by a mid-cycle facelift. The first examples of the ZX had been produced in 1990, with the three door Rally Raid model being the winner of the Paris-Dakar , which started just after Christmas. The first prototypes of

325-595: A ground breaking and radical new model in the small family car market on its launch in 1970, scooping the European Car of the Year award, and was facelifted in 1979 and gained a hatchback which saw it transformed into the GSA. However, such was the success of the larger BX after its 1982 launch, that PSA decided to delay the launch of an immediate replacement for the GSA when it was finally discontinued in 1986. Development work began on

390-571: A hydraulic system to assist the driver of the vehicle . Sensors detect the position and torque exerted inside the steering column, and a computer module applies assistive torque via the motor, which connects either to the steering gear or steering column. This allows varied amounts of assistance to be applied depending on driving conditions. Engineers can therefore tailor steering-gear response to variable-rate and variable-damping suspension systems, optimizing ride, handling, and steering for each vehicle. This new technological feature also gave engineers

455-512: A license plate number beginning with "5". In the past, the small size category has received tax benefits stipulated by the Japanese government regulations , such as those in the 1951 Road Vehicle Act . In 1955, the Japanese Ministry of International Trade and Industry set forth a goal to all Japanese makers at that time to create what was called a "national car". The concept stipulated that

520-519: A new C segment hatchback, which was originally expected to be launched as the Citroën FX at the beginning of the 1990s. Although the Rally Raid version of the ZX debuted during 1990, the ZX was officially launched on the left hand drive continental markets on 16 March 1991, with British sales beginning in May that year, initially only with petrol engines. The diesel ZX went on sale later in 1991. The ZX

585-745: A new market segment and the U.S. automobile industry soon adopted the "compact" term. Several competitors to the Nash Rambler arose from the ranks of America's other independent automakers, although none enjoyed the long-term success of the Rambler. Other early compact cars included the Kaiser-Frazer Henry J (also re-badged as the Allstate ), the Willys Aero and the Hudson Jet . In 1954, 64,500 cars sold in

650-524: A rack assist without a clutch was put into practical use in the Honda NSX (initially installed in automatics only). Since then, there has been a transition of trend from brush-attached motors to brushless motors in the rack type for ordinary vehicles and this method has become the mainstream. Other electric power steering systems (including 4WS) later appeared on the Honda NSX after 1990, the Honda Prelude and

715-481: A smaller model, and then adding a larger model (the Xantia ) to its range. The ZX's interior space and value received praise from critics and consumers. Of particular note was the unusual rear seat arrangement: the rear bench was mounted on a sliding platform that allowed it to be moved rearwards to increase rear legroom, or forwards to increase cargo space or to allow the seat back to be tilted backwards. Unfortunately, only

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780-414: A two-part frame with a rugged hinge in the middle; this hinge allows the front and rear axles to become non-parallel to steer the vehicle. Opposing hydraulic cylinders move the halves of the frame relative to each other to steer. The first power steering system on a vehicle was apparently installed in 1876 by a man with the surname of Fitts, but little else is known about him. The next power steering system

845-555: Is proportional to road speed, so that at low speeds the steering is very light, and at high speeds it is very difficult to move more than a small amount off centre. It was invented by Citroën of France. This system was first introduced in the Citroën SM in 1970, and was known as 'VariPower' in the UK and 'SpeedFeel' in the U.S. Electro-hydraulic power steering systems, sometimes abbreviated EHPS, and also sometimes called "hybrid" systems, use

910-470: Is required or not, and this is a major reason for their introduction. Another major advantage is the elimination of a belt-driven engine accessory, and several high-pressure hydraulic hoses between the hydraulic pump, mounted on the engine, and the steering gear, mounted on the chassis. This greatly simplifies manufacturing and maintenance. By incorporating electronic stability control electric power steering systems can instantly vary torque assist levels to aid

975-405: Is the medium by which pressure is transmitted. Common working liquids are based on mineral oil . Some modern systems also include an electronic control valve to reduce the hydraulic supply pressure as the vehicle's speed increases; this is variable-assist power steering. DIRAVI innovated the now common benefit of speed sensitive steering . In this power steering system, the force steering

1040-689: The Canadian Intellectual Property Office in 1958. Starting in the mid-1950s American manufacturers offered the technology as optional or standard equipment while it is widely offered internationally on modern vehicles, owing to the trends toward front-wheel drive , greater vehicle mass, reduced assembly line production costs, and wider tires , which all increase the required steering effort. Heavier vehicles, as are common in some countries, would be extremely difficult to maneuver at low speeds, while vehicles of lighter weight may not need power assisted steering at all. A study in 1999 on

1105-517: The Golf Mk3 Ecomatic , with an electric pump. This meant that the power steering would still operate while the engine was stopped by the computer to save fuel. Electro-hydraulic systems can be found in some cars by Ford , Volkswagen , Audi , Peugeot , Citroën , SEAT , Škoda , Suzuki , Opel , MINI , Toyota , Honda , and Mazda . Electric power steering ( EPS ) or motor-driven power steering ( MDPS ) uses an electric motor instead of

1170-681: The Recession of 1958 , the only exception to the sales decline was American Motors with its compact, economy-oriented Ramblers that saw high demand among cautious consumers. By 1959, sales of small imported cars also increased to 14% of the U.S. passenger car market, as consumers turned to compact cars. By this time, smaller cars appealed to people with a college education and a higher income whose families were buying more than one car. Customers expected compact cars to provide improved fuel economy compared to full-sized cars while maintaining headroom, legroom, and plenty of trunk space. Between 1958 and 1960,

1235-493: The electronic stability control system to alter steering gear ratios and steering assist levels. In 2003, BMW introduced " active steering " system on the 5 Series . This system should not be confused with variable assist power steering, which varies steering assist torque, not steering ratios, nor with systems where the gear ratio is only varied as a function of steering angle. These last are more accurately called non-linear types (e.g. Direct-Steer offered by Mercedes-Benz );

1300-405: The "Furio", a cheaper model with a sporting tone combined with the lesser engines, a 16-valve engined high performance derivative, and many special editions. The ZX was initially available as a three- or five-door hatchback , while a five-door estate was added to the range in 1994. It was offered with petrol engines from 1.1 L to 2.0 L, as well as three 1.9 L diesel engines including

1365-466: The "small Ford" and produced the Ford Vedette . The first U.S.-produced postwar compact car was the 1950 Nash Rambler . It was built on a 100-inch (2,540 mm) wheelbase, which was nonetheless still a large car by contemporary European standards. The term "compact" was coined by a Nash executive as a euphemism for small cars with a wheelbase of 110 inches (2,794 mm) or less. It established

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1430-791: The 1980s that American cars were being downsized to truly international dimensions. In the 1985 model year, compact cars classified by the EPA included Ford's Escort and Tempo as well as the Chevrolet Cavalier. For the 2019 model year, the best sellers were the Toyota Corolla and Honda Civic. In Japan, vehicles that are larger than kei cars , but with dimensions smaller than 4,700 mm (185.0 in) long, 1,700 mm (66.9 in) wide, 2,000 mm (78.7 in) high and with engines at or under 2,000 cc (120 cu in) are classified as "small size" cars. Small-size cars are identified by

1495-563: The British and American armies. Chrysler Corporation introduced the first commercially available passenger car power steering system on the 1951 Chrysler Imperial under the name "Hydraguide". The Chrysler system was based on some of Davis' expired patents. General Motors introduced the 1952 Cadillac with a power steering system using the work Davis had done for the company almost twenty years earlier. Charles F. Hammond from Detroit filed several patents for improvements of power steering with

1560-580: The Honda City, Toyota Yaris, Toyota Corolla Altis 1.6, and the Changan Alsvin. Power steering Power steering is a system for reducing a driver's effort to turn a steering wheel of a motor vehicle , by using a power source to assist steering . Hydraulic or electric actuators add controlled energy to the steering mechanism, so the driver can provide less effort to turn the steered wheels when driving at typical speeds, and considerably reduce

1625-583: The Mark III Volkswagen Golf , which was priced at a premium when launched in August 1991. The familiar range of PSA powertrains drove the front wheels of a seemingly conventionally designed chassis. At the front was a standard MacPherson strut layout with anti-roll bar , while the rear used the PSA Peugeot-Citroën fully independent trailing arm / torsion bar set up that was first introduced on

1690-607: The RZ 450e featuring a steer-by-wire system which eliminates the mechanical linkage between the steering wheel and the wheels, marking a significant advancement in power steering technology. In 2000, the Honda S2000 Type V featured the first electric power variable gear ratio steering (VGS) system. In 2002, Toyota introduced the "Variable Gear Ratio Steering" (VGRS) system on the Lexus LX 470 and Landcruiser Cygnus, and also incorporated

1755-897: The Subaru SVX in 1991, the Nissan 300ZX (Z32; after the Version 3 onwards), Silvia, Skyline, and the Laurel in 1993, the MG F, the FIAT Punto Mk2 in 1999, the Honda S2000 in 1999, Toyota Prius in 2000, the BMW Z4 in 2002, and the Mazda RX-8 in 2003. The system has been used by various automobile manufacturers, and most commonly applied for smaller cars to reduce fuel consumption and manufacturing costs . In 2023, Lexus introduced

1820-407: The U.S. were imports or small American cars, out of a total market of five million cars. Market research indicated that five percent of those surveyed said they would consider a small car, suggesting a potential market size of 275,000 cars. By 1955, the Nash Rambler that began as a convertible model became a success and was now available in station wagon , hardtop , and sedan body styles. During

1885-1009: The Xsara Picasso. It was replaced by the Xsara in September 1997, but production in Europe continued until 1998. The ZX was the first Citroën built in China . A saloon derivative, called the Citroën Elysée , along with the China-based ZX known as the Fukang , continued to be produced for the Chinese market by the Dongfeng Peugeot-Citroën Automobile , a joint venture with the Dongfeng Motor Corporation . The Citroën GS had been

1950-721: The ZX 16V Turbo in the hands of Kenneth Hansen (rallycross) took two FIA European Rallycross Championship titles. 1994 and 1996. The ZX Kit Car, a front-wheel-drive naturally aspirated rally car built to the F2 rules, won the 1997 Spanish rally championship thanks to Jesús Puras . Compact car In Japan, small size passenger vehicle is a registration category that sits between kei cars and regular cars, based on overall size and engine displacement limits. The United States Environmental Protection Agency (EPA) Fuel Economy Regulations for 1977 and Later Model Year (dated July 1996) includes definitions for classes of automobiles. Based on

2015-504: The ZX had actually debuted at the Baja Aragon on 20 July 1990. Drag resistance ranged from Cds 0.30 to 0.33. The launch of the ZX marked the return of Citroën into the C sector of the car market; it had discontinued the GSA in 1986 with no immediate replacement, largely due to the success of the larger BX. However, Citroën had decided to phase out the BX between 1990 and 1993, by at first launching

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2080-426: The ability to add new driver assistance features. This includes features such as lane assist, wind drift correction, etc. On Fiat group cars the amount of assistance can be regulated using a button named "CITY" that switches between two different assist curves, while most other EPS systems have variable assist. These give more assistance as the vehicle slows down, and less at faster speeds. A mechanical linkage between

2145-705: The beginning of a downsizing of all vehicles so that cars such as the AMC Concord and the Ford Fairmont that replaced the compacts were re-classified as mid-size, while cars inheriting the size of the Ford Pinto and Chevrolet Vega (such as the Ford Escort and Chevrolet Cavalier ) became classified as compact cars. Even after the reclassification, mid-size American cars were still far larger than mid-size cars from other countries and were more similar in size to cars classified as "large cars" in Europe. It would not be until

2210-413: The bottom end usually resists being rotated, the bar will twist by an amount proportional to the applied torque. The difference in position between the opposite ends of the torsion bar controls a valve. The valve allows fluid to flow to the cylinder which provides steering assistance; the greater the "twist" of the torsion bar, the greater the force. Since the hydraulic pumps are positive-displacement type,

2275-564: The combined passenger and cargo volume, compact cars are defined as having an interior volume index of 100–109 cu ft (2.8–3.1 m ). The beginnings of U.S. production of compact cars were the late 1940s prototypes of economy cars, including the Chevrolet Cadet and the Ford Light Car. Neither car reached production in the U.S., however Ford SAF in France bought the plans of

2340-492: The driver in corrective maneuvers. In 1986, NSK put the world’s first electric power steering system for battery forklifts into practical use. In 1988, Koyo Seiko (currently JTEKT) and NSK co-developed a column system exclusively for minicars sold only in the domestic market of Japan. The first-ever electric power steering system for mass-produced passenger cars appeared on the Suzuki Cervo in 1988. However, this simple method

2405-450: The driver, steering assist loss may or may not lead to a crash. The difficulty of steering with inoperative power steering is compounded by the choice of steering ratios in assisted steering gears vs. fully manual. The NHTSA has assisted car manufacturers with recalling EPS systems prone to failure. Electric systems have an advantage in fuel efficiency because there is no belt-driven hydraulic pump constantly running, whether assistance

2470-534: The engine stalled. In 1988, the Subaru XT6 was fitted with a unique Cybrid adaptive electro-hydraulic steering system that changed the level of assistance based on the vehicle's speed. In 1990, Toyota introduced its second-generation MR2 with electro-hydraulic power steering. This avoided running hydraulic lines from the engine (which was behind the driver in the MR2) up to the steering rack. In 1994 Volkswagen produced

2535-471: The estate of the Peugeot 305 . However, PSA's chassis engineers employed some unusual features, including passive rear-wheel steering to induce compliance understeer by means of specially designed bushes in the rear suspension. At high mileages, this is prone to wear off the axle mounting bushes, which is easily fixed. The rear shock absorbers were developed and constructed in house. It is also prone to wear in

2600-438: The first practical power steering system. Davis moved to General Motors and refined the hydraulic-assisted power steering system, but the automaker calculated it would be too expensive to produce. Davis then signed up with Bendix , a parts manufacturer for automakers. Military needs during World War II for easier steering on heavy vehicles boosted the need for power assistance on armored cars and tank-recovery vehicles for

2665-427: The flow rate they deliver is directly proportional to the speed of the engine. This means that at high engine speeds the steering would naturally operate faster than at low engine speeds. Because this would be undesirable, a restricting orifice and flow-control valve direct some of the pump's output back to the hydraulic reservoir at high engine speeds. A pressure relief valve prevents a dangerous build-up of pressure when

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2730-476: The hydraulic cylinder's piston reaches the end of its stroke. The steering booster is arranged so that should the booster fail, the steering will continue to work (although the wheel will feel heavier). Loss of power steering can significantly affect the handling of a vehicle. Each vehicle owner's manual gives instructions for inspection of fluid levels and regular maintenance of the power steering system. The working liquid, also called " hydraulic fluid " or "oil",

2795-462: The large family car market by being "between sizes" but well packaged. For 1993, the Citroën ZX chassis was also used for the Peugeot 306 which, with its attractive Peugeot 205 derived styling, was an even more successful car than its twin. The Citroën Berlingo and Peugeot Partner were also built on the front half of the same platform, the rear coming from the 405, an arrangement shared underneath

2860-518: The major U.S. car manufacturers made a push toward compact cars, resulting in the introduction of the Studebaker Lark , Chevrolet Corvair , Ford Falcon , and Plymouth Valiant . These models also gave rise to compact vans built on the compact car platforms, such as the Studebaker Zip Van, Chevrolet Corvair Greenbrier , Ford Econoline , and Dodge A100 . During the 1960s, compacts were

2925-422: The more fluid the valves allow through to the cylinder, and so the more force is applied to steer the wheels. One design for measuring the torque applied to the steering wheel has a torque sensor – a torsion bar at the lower end of the steering column. As the steering wheel rotates, so does the steering column, as well as the upper end of the torsion bar. Since the torsion bar is relatively thin and flexible, and

2990-679: The passenger and cargo compartments were introduced in the late 1970s. In the early 1970s, the domestic automakers introduced even smaller subcompact cars that included the AMC Gremlin , Chevrolet Vega , and Ford Pinto . In 1973, the Energy Crisis started, which made small fuel-efficient cars more desirable, and the North American driver began exchanging their large cars for the smaller, imported compacts that cost less to fill up and were inexpensive to maintain. The 1977 model year marked

3055-406: The perceptual fidelity of steering force feedback, found that ordinary real-world truck and car drivers naturally expect an increase in feedback torque as speed increases, and for this reason early forms of power steering, which lacked such effect, were met with disapproval. Hydraulic power steering systems work by using a hydraulic system to multiply force applied to the steering wheel inputs to

3120-404: The physical effort necessary to turn the wheels when a vehicle is stopped or moving slowly. Power steering can also be engineered to provide some artificial feedback of forces acting on the steered wheels. Hydraulic power steering systems for cars augment steering effort via an actuator, a hydraulic cylinder that is part of a servo system . These systems have a direct mechanical connection between

3185-630: The popular Volkswagen Beetle . Compact cars were also the basis for a new small car segment that became known as the pony car , named after the Ford Mustang , which was built on the Falcon chassis. At that time, there was a distinct difference in size between compact and full-size models. Early definitions of vehicle size class were based on wheelbase, with models under 111 inches as compact, 111 to 118 inches intermediate, and over 118 inches as full size, at least until EPA classes based on interior volume of

3250-531: The power steering system. Other power steering systems (such as those in the largest off-road construction vehicles) have no direct mechanical connection to the steering linkage; they require electrical power. Systems of this kind, with no mechanical connection, are sometimes called " drive by wire " or "steer by wire", by analogy with aviation's " fly-by-wire ". In this context, "wire" refers to electrical cables that carry power and data, not thin wire rope mechanical control cables. Some construction vehicles have

3315-424: The rear axle trailing arm bearings, which then wear the trailing arm axle tubes, requiring an expensive rebuild or a replacement axle assembly. The diesel and larger capacity petrol engines are canted as far back as possible in the engine bay, in an effort to put as much weight as possible behind the front axle line, also reducing the centre of gravity, while improving weight distribution and minimising understeer. At

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3380-429: The same hydraulic assist technology as standard systems, but the hydraulic pressure comes from a pump driven by an electric motor instead of a drive belt at the engine. In 1965, Ford experimented with a fleet of "wrist-twist instant steering" equipped Mercury Park Lanes that replaced the conventional large steering wheel with two 5-inch (127 mm) rings, a fast 15:1 gear ratio, and an electric hydraulic pump in case

3445-499: The seat backs folded forward on models so fitted; lower specification models had more ultimate cargo capacity as the rear seat cushion folded up, allowing the seat back to be laid down flat. The ZX's specifications were good for its class, with most models getting power steering , electric windows, electric sunroof, a driver's side (and sometimes passenger's side) airbag , and anti-lock braking system as either optional or standard equipment. It remained competitively priced though, unlike

3510-538: The smallest class of North American cars, but they had evolved into only slightly smaller versions of the 6-cylinder or V8-powered six-passenger sedan. They were much larger than compacts (and sometimes even mid-sizers) by European manufacturers, which were typically five-passenger four-cylinder engine cars. Nevertheless, advertising and road tests for the Ford Maverick and the Rambler American made comparisons with

3575-399: The steering wheel and the linkage that steers the wheels. This means that power-steering system failure (to augment effort) still permits the vehicle to be steered using manual effort alone. Electric power steering systems use electric motors to provide the assistance instead of hydraulic systems. As with hydraulic types, power to the actuator (motor, in this case) is controlled by the rest of

3640-491: The steering wheel and the steering gear is retained in EPS. In the event of component failure or power failure that causes a failure to provide assistance, the mechanical linkage serves as a back-up. If EPS fails, the driver encounters a situation where heavy effort is required to steer. This heavy effort is similar to that of an inoperative hydraulic steering assist system . Depending on the driving situation, driving skill and strength of

3705-462: The time of its launch, the ZX range consisted of a collection of four very individual trim levels; the base model was the "Reflex" aimed at young people, next was the "Avantage" aimed at families, and then there was the luxury "Aura" series. The final series was the relatively sporting "Volcane" series, with lowered (and hard) suspension. The later "Volcane" TD was one of the first diesel hot hatches . Over time, further models were introduced, including

3770-807: The time, while the Datsun was an all-new vehicle. These vehicles were followed by the Hino Contessa in 1961, the Isuzu Bellett , Daihatsu Compagno and Mazda Familia in 1963, the Mitsubishi Colt in 1965, and the Nissan Sunny , Subaru 1000 , and Toyota Corolla in 1966. Honda introduced its first four-door sedan in 1969, called the Honda 1300 . In North America, these cars were classified as subcompact cars . By 1970, Nissan released its first front-wheel-drive car which

3835-399: The vehicle be able to maintain a maximum speed over 100 km/h (62 mph), weigh below 400 kg (882 lbs), fuel consumption at 30 km/L (85 mpg ‑imp ; 71 mpg ‑US ) or more, at an average speed of 60 km/h (37 mph) on a level road, and not require maintenance or significant service for at least 100,000 km (62,000 mi). This established

3900-412: The vehicle's steered (usually front) road wheels. The hydraulic pressure typically comes from a gerotor or rotary vane pump driven by the vehicle's engine. A double-acting hydraulic cylinder applies a force to the steering gear, which in turn steers the roadwheels. The steering wheel operates valves to control flow to the cylinder. The more torque the driver applies to the steering wheel and column,

3965-421: The wheels comes from the car's high pressure hydraulic system and is always the same no matter what the road speed is. Turning the steering wheel moves the wheels simultaneously to a corresponding angle via a hydraulic cylinder. In order to give some artificial steering feel, there is a separate hydraulically operated system that tries to turn the steering wheel back to centre position. The amount of pressure applied

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4030-523: Was helped at the time of introduction by having reached the market a few months before the new version of the Opel / Vauxhall Astra . The sales target was about 230,000 vehicles per year, with half of that number going outside of France . It went on sale in New Zealand in the beginning of 1993, as a five door in 1.6 Aura or Turbodiesel trim, with the naturally aspirated diesel and Volcane GTi (1.9) models joining

4095-415: Was not widely adopted by other automakers in the initial years due to the unnatural steering feel of the motor caused by the inertia at the time of rapid steering for danger avoidance in slower speed driving, as well as at the time of faster speed driving in which the electromagnetic clutch makes the steering force smaller, returning to the manual steering mode. In the year 1990, a direct full control system of

4160-598: Was originally developed by Prince Motor Company which had merged with Nissan in 1966. This was introduced in 1970 as the Nissan Cherry . In 1972, the Honda Civic appeared with the CVCC engine that was able to meet California emission standards without the use of a catalytic converter . In Pakistan, the concept of compact cars is significant. The most common cars tend to be Kei cars . Popular compact cars in recent times are

4225-523: Was put on a Columbia 5-ton truck in 1903 where a separate electric motor was used to assist the driver in turning the front wheels. Robert E. Twyford , a resident of Pittsburgh , Pennsylvania , included a mechanical power steering mechanism as part of his patent (U.S. Patent 646,477) issued on April 3, 1900 for the first four-wheel drive system. Francis W. Davis , an engineer of the truck division of Pierce-Arrow , began exploring how steering could be made easier, and in 1926 invented and demonstrated

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