| Citroën 2CV | |
|---|---|
 | |
| Overview | |
| Manufacturer | Citroën |
| Production | 1948–1990[1] |
| Assembly | Levallois-Perret, France,[2] Forest/Vorst, Belgium Liège, Belgium Slough, UK Jeppener, Argentina (1960–1962), Buenos Aires, Argentina (1962–1980) Montevideo, Uruguay (Panel van & pick-up) Arica, Chile Mangualde, Portugal (1988–1990), Vigo, Spain (PSA Vigo Plant) Koper, Slovenia (former Yugoslavia) |
| Designer | André Lefèbvre Flaminio Bertoni Walter Becchia Marcel Chinon |
| Body and chassis | |
| Class | Economy car |
| Body style | 4-door saloon 5-door hatchback (3CV) 2-door panel van 2-door pick-up 2-door coupé utility |
| Layout | Front engine, front-wheel drive / four-wheel drive |
| Related | Citroën Ami Citroën Dyane Citroën Acadiane Citroën FAF Citroën Méhari Citroën Bijou |
| Powertrain | |
| Engine | 375 cc H2 air-cooled 9 hp (7 kW). 425 cc H2 air-cooled 12 hp (9 kW). 435 cc H2 air-cooled 24 hp (18 kW). 602 cc H2 air-cooled 29 hp (22 kW). [3][page needed] |
| Transmission | 4-speed manual |
| Dimensions | |
| Wheelbase | 2,400 mm (94.5 in) |
| Length | 3,860 mm (152.0 in) |
| Width | 1,480 mm (58.3 in) |
| Height | 1,600 mm (63.0 in) |
| Curb weight | 600 kg (1,323 lb) |
| Chronology | |
| Successor | Citroën Dyane Citroën AX (indirectly) |
The Citroën 2CV (French: "deux chevaux" or "deux chevaux-vapeur", pronounced [dø.ʃə.vo], lit. "two steam horses", "two tax horsepower") is an air-cooled front-engine, The Citroën 2CV (French: "deux chevaux" or "deux chevaux-vapeur", pronounced [dø.ʃə.vo], lit. "two steam horses", "two tax horsepower") is an air-cooled front-engine, front-wheel-drive economy car introduced at the 1948 Paris Mondial de l'Automobile and manufactured by Citroën for model years 1948–1990.[1]
Conceived by Citroën Vice-President Pierre Boulanger[4] to help motorise the large number of farmers still using horses and carts in 1930s France, the 2CV has a combination of innovative engineering and utilitarian, straightforward metal bodywork—initially corrugated for added strength without added weight.[5][6][7] The 2CV featured low cost, simplicity of overall maintenance, an easily serviced air-cooled engine (originally offering 9 hp), low fuel consumption, and an extremely long-travel suspension[8] offering a soft ride and light off-road capability.
Often called "an umbrella on wheels",[9][10] the fixed-profile convertible bodywork featured a full-width, canvas, roll-back sunroof, which accommodated oversized loads and until 1955 reached almost to the car's rear bumper.
Michelin introduced and first commercialised the revolutionary new radial tyre design with the introduction of the 2CV.[11][12][13]
Manufactured between 1948 and 1990, more than 3.8 million 2CVs were produced. The car spawned many variants, as detailed in Production - Including all A-Series Variant Models section. The 2CV and its variants are collectively known as the A-Series. [14] Notably these include the 2CV-based delivery vans known as fourgonnettes, the Ami, the Dyane, the Acadiane, and the Mehari. In total, Citroën manufactured 9 million 2CVs and variants.[15]
A 1953 technical review in Autocar described "the extraordinary ingenuity of this design, which is undoubtedly the most original since the Model T Ford".[16] In 2011, The Globe and Mail called it a "car like no other".[17] The motoring writer L. J. K. Setright described the 2CV as "the most intelligent application of minimalism ever to succeed as a car",[18] and a car of "remorseless rationality".[19]
Both the design and the history of the 2CV mirror the Volkswagen Beetle in significant ways. Conceived in the 1930s, to make motorcars affordable to regular people for the first time in their countries, both went into large scale production in the late 1940s, featuring air-cooled boxer engines at the same end as their driven axle, omitting a length-wise drive shaft, riding on the exact same 2,400 mm (94.5 in) wheelbase, and using a platform chassis to facilitate the production of derivative models. Just like the Beetle, the 2CV became not only a million seller, but also one of the few cars in history to continue a single generation in production for over four decades.
Contents
- 1 History
- 2 Export markets
- 2.1 Britain
- 2.2 South A
Conceived by Citroën Vice-President Pierre Boulanger[4] to help motorise the large number of farmers still using horses and carts in 1930s France, the 2CV has a combination of innovative engineering and utilitarian, straightforward metal bodywork—initially corrugated for added strength without added weight.[5][6][7] The 2CV featured low cost, simplicity of overall maintenance, an easily serviced air-cooled engine (originally offering 9 hp), low fuel consumption, and an extremely long-travel suspension[8] offering a soft ride and light off-road capability.
Often called "an umbrella on wheels",[9][10] the fixed-profile convertible bodywork featured a full-width, canvas, roll-back sunroof, which accommodated oversized loads and until 1955 reached almost to the car's rear bumper.
Michelin introduced and first commercialised the revolutionary new radial tyre design with the introduction of the 2CV.[11][12][13]
Manufactured between 1948 and 1990, more than 3.8 million 2CVs were produced. The car spawned many variants, as detailed in Production - Including all A-Series Variant Models section. The 2CV and its variants are collectively known as the A-Series. [14] Notably these include the 2CV-based delivery vans known as fourgonnettes, the Ami, the Dyane, the Acadiane, and the Mehari. In total, Citroën manufactured 9 million 2CVs and variants.[15]
A 1953 technical review in Autocar described "the extraordinary ingenuity of this design, which is undoubtedly the most original since the Model T Ford".[16] In 2011, The Globe and Mail called it a "car like no other".[17] The motoring writer L. J. K. Setright described the 2CV as "the most intelligent application of minimalism ever to succeed as a car",[18] and a car of "remorseless rationality".[19]
Both the design and the history of the 2CV mirror the Volkswagen Beetle in significant ways. Conceived in the 1930s, to make motorcars affordable to regular people for the first time in their countries, both went into large scale production in the late 1940s, featuring air-cooled boxer engines at the same end as their driven axle, omitting a length-wise drive shaft, riding on the exact same 2,400 mm (94.5 in) wheelbase, and using a platform chassis to facilitate the production of derivative models. Just like the Beetle, the 2CV became not only a million seller, but also one of the few cars in history to continue a single generation in production for over four decades.
In 1934, family-owned Michelin, as the largest creditor, took over the bankrupt Citroën company. The new management commissioned a market survey, conducted by Jacques Duclos.[20] France at that time had a large rural population which could not yet afford cars; Citroën used the survey results to prepare a design brief for a low-priced, rugged "umbrella on four wheels" that would enable four people to transport 50 kg (110 lb) of farm goods to market at 50 km/h (30 mph),[21] if necessary across muddy, unpaved roads. In fuel economy, the car would use no more than 3 l/100 km (95 mpg‑imp; 80 mpg‑US). One design parameter required that customers be able to transport eggs across a freshly ploughed field without breakage.[22]
In 1936, Pierre-Jules Boulanger, vice-president of Citroën and chief of engineering and design, sent the brief to his design team at the engineering department. The TPV (Toute Petite Voiture – "Very Small Car") was to be developed in secrecy at Michelin facilities at Clermont-Ferrand and at Citroën in Paris, by the design team who had created the Traction Avant.[23]
Boulanger closely monitored all decisions relating to the TPV, proposing strictly reduced target weights. He created a department to weigh and redesign each component, to lighten the TPV without compromising function.[24]
Boulanger placed engineer André Lefèbvre in charge of the TPV project.[25] Lefèbvre had designed and raced Grand Prix cars; his speciality was chassis design and he was particularly interested in maintaining contact between tyres and the road surface.[26]
The first prototypes were bare chassis with rudimentary controls, seating and roof; test drivers wore leather flying suits, of the type used in contemporary open biplanes.[27] By the end of 1937 20 TPV experimental prototypes had been built and tested.[27] The prototypes had only one headlight, all that was required by French law at the time.[23] On 29 December 1937, Pierre Michelin was killed in a car crash; Boulanger became president of Citroën.[28]
By 1939 the TPV was deemed ready, after 47 technically different and incrementally improved experimental prototypes had been built and tested.[29] These prototypes used aluminium and magnesium parts and had water-cooled flat twin engines with front-wheel drive. The seats were hammocks hung from the roof by wires. The suspension system, designed by Alphonse Forceau, used front leading arms and rear trailing arms, connected to eight torsion bars beneath the rear seat: a bar for the front axle, one for the rear axle, an intermediate bar for each side, and an overload bar for each side. The front axle was connected to its torsion bars by cable. The overload bar came into play when the car had three people on board, two in the front and one in the rear, to support the extra load of a fourth passenger and fifty kilograms of luggage.[5][unreliable source?]
In mid-1939 a pilot run of 250 cars was produced and on 28 August 1939 the car received approval for the French market.[29][30] Brochures were printed and preparations made to present the car, renamed the Citroën 2CV, at the forthcoming Paris Motor Show in October 1939.[30]
One innovation included from the beginning of production was Michelin's new radial tyre, first commercialised with the introduction of the 2CV.[31] This radial design is an integral part of the design of the 2CV chassis.[32]
World War II
In Germany and Switzerland a special edition called "I Fly Bleifrei" ("I Fly Lead Free") was launched in 1986, that could use unleaded, instead of then normal leaded petrol and super unleaded. It was introduced mainly because of stricter emissions standards. In 1987 it was replaced by the "Sausss-duck" special edition.[citation needed]
Export markets
Production at Citroën's plant in Slough, England was from 1953 to 1960. Until then British construction and use regulations made cars with inboard front brakes such as the 2CV illegal. Producing the car in Britain allowed Citroën to circumvent trade barriers and to sell cars in the British Empire and Commonwealth. It achieved some success in these markets, to the extent that all Slough-built 2CVs were fitted with improved air cleaners and other modifications to suit the rough conditions found in Australia and Africa, where the 2CV's durability and good ride quality over rough roads attracted buyers. The 2CV sold poorly in Great Britain in part due to its excessive cost, because of import duties on components.
In 1959, the British Royal Navy ordered 65 2CV pick-ups from the Slough plant, following sea tests aboard HMS Bulwark in the West Indies and the Indian Ocean during 1957–58, with the Westland Whirlwind helicopters of 845 squadron RNAS. The pick-ups also served aboard HMS Albion. They were to serve as motor transport with the 42nd Commando regiment of the Royal Marines, which required robust and reliable vehicles to cope with jungle tracks, that were light enough to be taken ashore by helicopter from the aircraft carriers.[68][69]
In 1959 Slough introduced a unique model, the glass-fibre coupé version called the Bijou. Styling of this car was by Peter Kirwan-Taylor (better known for his work with Colin Chapman of Lotus cars on the 1950s Lotus Elite), but the bodywork proved too heavy for the 425 cc (25.9 cu in) engine to endow it with adequate performance.
In 1975, the 2CV was re-introduced to the British market in the wake of the oil crisis, which resulted in an increasing demand for smaller cars, to which most manufacturers had responded by launching small "supermini" cars, including the Renault 5, Ford Fiesta and Volkswagen Polo.
The second wave of 2CVs for the British market were produced in France but avoided the crippling import duties of the 1950s, because the UK was by then a member of the EEC. In the 1980s, the best foreign markets for the 2CV were the UK and West Germany.[43][unreliable source?]
South America
The 1953 Citroneta mo
The 1953 Citroneta model of the 2CV made in Chile and Argentina used a type AZ chassis with 425 cc engine developing 12 bhp (8.9 kW). Both chassis and engine were made in France while the "three box" bodywork (in both 2- and 4-door versions) was designed and produced in Chile. It was the first economy car on the market in Chile. The 1970s Chilean version mounted a 602 cc engine with an output of 33 hp (25 kW), and was designated as the AX-330. It was built between 1970 and 1978, during which it saw changes like different bumpers, a hard roof, front disc brakes, and square headlights.[70]
One of the Citroën FAF models, named the Yagán after an Indigenous peoples tribe, was made in Chile between 1972 and 1973.One of the Citroën FAF models, named the Yagán after an Indigenous peoples tribe, was made in Chile between 1972 and 1973.[71] During the Chilean coup of 1973, 200 Yagáns used by the Army to patrol the streets and the Peruvian border, with 106 mm (4.2 in) cannons.[citation needed]
From 1965, Nordex produced its own panel van and pick-up versions of the Citroën 2CV. While the doors and the rear structure (in the case of the panel van, the roof as well) were made of sheet steel, the fenders and bonnet were made by Dasur (Danrée, Soler & Bonet) and were made of fiberglass-reinforced plastic. In contrast to the original, the frame was manufactured on a sheet metal bending machine. Start of production was 1966 for the "3CV" model and the Ami 8 model in the 1970s.
The Citroën Méhari and Ranger were produced in a Uruguayan assembly plant between 1970 and 1982. In a joint effort, Dasur made the body out of fiberglass and Nordex made the chassis, while Quintanar sold the vehicles. Around 14,000 vehicles were built, 9,000 of which were exported to Argentina and
The Citroën Méhari and Ranger were produced in a Uruguayan assembly plant between 1970 and 1982. In a joint effort, Dasur made the body out of fiberglass and Nordex made the chassis, while Quintanar sold the vehicles. Around 14,000 vehicles were built, 9,000 of which were exported to Argentina and the rest remained inland.
For the Méhari, a two-cylinder boxer engine with a 74 mm bore, 70 mm stroke, 602 cm³ displacement and 35 hp power drove the front wheels. The curb weight was 590 kg.
The Méhari Ranger represented a national specialty. With a fixed structure, the Méhari became a station wagon with large glass surfaces. The side windows in front of the doors were also striking. The rear wheel cutouts also differed from the original. This vehicle weighed 700 kg. [72]
From 1978 onwards, Nordex manufactured the Citroen AK 400 from Argentine and Belgian parts for the Argentine market.
Another model produced was the Citroën BX, which had been exported to Brazil since 1992. The production of the Citroën ZX is documented for Nordex in 1995. In Uruguay, Citroën cars were manufactured until 2002.
Citroën Argentina Sociedad Anónima produced 223,442 cars (all A-Series), in Argentina, from 1959 until the revolution came in 1979.[73]
Model designations produced were the 2CV sedan, 3CV sedan, AZU van, AK van, AK 400 van, AMI 8, and Méhari.[74] The derivation called "3CV" was a special Argentina model with various modifications such as a [74] The derivation called "3CV" was a special Argentina model with various modifications such as a hatchback. [73]
Citroën Argentina S.A. exported parts to France, Spain, and Chile. Complete automobiles were exported to Paraguay, Bolivia and Cuba. Chassis with mechanics to Uruguay (some returned to the plant as completed Mehari or AK-400 models).[73]
Citroën Argentina outsourced parts to 450 auto parts companies, the national content of the vehicles was over 95% by 1969. [73]
A 2CV with a heavily modified front end called the 3CV IES America was produced well into the 1980s, by an Argentinian company that bought the rights and factory from Citroën.[75][76]
Only a few [77] 2CVs were sold in North America when they were new; similar to the situation in Britain, their pricing was excessive relative to competitors. The original model that produced 9 hp (6.7 kW) and had a top speed of 64 km/h (40 mph) was unsuited to the expanding post-war US freeway network, and was never widely accepted in North America. Even the fastest of the later models struggled to 115 km/h (71 mph).[78]
Yugoslavia
Also i
Also in 1959, the Yugoslav firm Tomos began producing the 2CV under licence at the Koper plant, in what is today Slovenia. This venture lasted from 1959 to 1985, and grew to encompass many Citroën models. The Yugoslav automobile market was closed, so this joint venture with a local firm allowed Citroën to access the market.[79]
Africa
In the
In Madagascar, a former colony of France, the 2CV is so ubiquitous given its use as a taxi that is popularly considered to be a symbol of the country itself.[82]
In Madagascar, a former colony of France, the 2CV is so ubiquitous given its use as a taxi that is popularly considered to be a symbol of the country itself.[82]
In 1966, Citroën entered Iran with the 2CV. The 2CV was soon supplanted by the Jiane, a local version of the Citroën Dyane.[83] The cars were originally manufactured in Iran in a joint venture between Citroën and Iran National up until the 1979 Revolution, when Iran National was nationalised, which continued producing the Jiane without the involvement of Citroën.[84]
Production
The body was constructed of a dual H-frame platform chassis and aircraft-style tube framework, and a very thin steel shell that was bolted to the chassis.[98][99] Because the original design brief called for a low speed car, little or no attention was paid to aerodynamics; the body had a drag coefficient of Cd=0.51, high by today's standards but typical for the era.
The 2CV used the fixed-profile convertible, where the doors and upper side elements of its bodywork remain fixed although, the doors could be removed easily too by lifting them up and way from the car. The bonnet too could be removed by sliding sideways to allow extra ventilation on very hot days. The fabric soft top can be rolled back and a picnic basket was available for purchase and fixed on the boot door. This reduces weight and lowers the centre of gravity, and allows the carrying of long or irregularly shaped items, but the key reason was that fabric was cheaper than steel which was in short supply and expensive after the war. The fixed-profile concept was quite popular in this period.[citation needed]
Suspension
The suspension of the 2CV was very soft; a person could easily rock the car side to side dramatically. The swinging arm, fore-aft linked suspension system with inboard front brakes had a much smaller unsprung mass than existing coil spring or leaf spring designs. The design was modified by Marcel Chinon.[35]
The system comprises two suspension cylinders mounted horizontally on each side of the platform chassis. Inside the cylinders are two springs, one for each wheel, mounted at each end of the cylinder. The springs are connected to the front leading swinging arm and rear trailing swinging arm, that act like bellcranks by pull rods (tie rods). These are connected to spring seating cups in the middle of the cylinder, each spring being compressed independently, against the ends of the cylinder.[35][100][101][102][100] Each cylinder is mounted using an additional set of springs, originally made from steel, called "volute" springs, on later models made from rubber. These allow the front and rear suspension to interconnect.[103] When the front wheel is deflected up over a bump, the front pull rod compresses the front spring inside the cylinder, against the front of the cylinder. This also compresses the front "volute" spring pulling the whole cylinder forwards. That action pulls the rear wheel down on the same side via the rear spring assembly and pull rod. When the rear wheel meets that bump a moment later, it does the same in reverse, keeping the car level front to rear. When both springs are compressed on one side when travelling around a bend, or front and rear wheels hit bumps simultaneously, the equal and opposite forces applied to the front and rear spring assemblies reduce the interconnection.[5][unreliable source?] It reduces pitching, which is a particular problem of soft car suspension.[5][unreliable source?]
The swinging arms are mounted with large bearings to "cross tubes" that run side to side across the chassis; combined with the effects of all-independent soft springing and excellent damping, keeps the road wheels in contact with the road surface and parallel to each other across the axles at high angles of body roll. A larger than conventional steering castor angle, ensures that the front wheels are closer to vertical than the rears, when cornering hard with a lot of body roll. The soft springing, long suspension travel and the use of leading and trailing arms means that as the body rolls during cornering the wheelbase on the outside of the corner increases while the wheelbase on the inside of the corner decreases. As the cornering forces put more of the car's weight on the outside pair of wheels the wheelbase extends in proportion, keeping the car's weight balance and centre of grip constant, promoting excellent road holding. The other key factor in the quality of its road holding is the very low and forward centre of gravity, provided by the position of the engine and transmission.[104]
The suspension also automatically accommodates differing payloads in the car- with four people and cargo on board the wheelbase increases by around 4 cm (2 in) as the suspension deflects, and the castor angle of the front wheels increases by as much as 8 degrees thus ensuring that ride quality, handling and road holding are almost unaffected by the additional weight.[105] On early cars friction dampers (like a dry version of a multi-plate clutch design) were fitted at the mountings of the front and rear swinging arms to the cross-tubes. Because the rear brakes were outboard, they had extra tuned mass dampers to damp wheel bounce from the extra unsprung mass. Later models had tuned mass dampers ("batteurs") at the front (because the leading arm had more inertia and "bump/thump" than the trailing arm), with hydraulic telescopic dampers / shock absorbers front and rear. The uprated hydraulic damping obviated the need for the rear inertia dampers.[106] It was designed to be a comfortable ride by matching the frequencies encountered in human bipedal motion.[8]
This suspension design ensured the road wheels followed ground contours underneath them closely, while insulating the vehicle
The 1948 car featured radial tyres, which had just been commercialised;[96] front-wheel drive; rack and pinion steering mounted inside the front suspension cross-tube, away from a frontal impact; rear fender skirts (the suspension design allowed wheel changes without removing the skirts); bolt-on detachable front and rear wings; detachable doors, bonnet (and boot lid after 1960), by "slide out" P-profile sheet metal hinges; flap-up windows, as roll up windows were considered too heavy and expensive.;[97] and detachable full length fabric sunroof and boot lid, for almost pickup-like load-carrying versatility. Ventilation in addition to the sunroof and front flap windows was provided by an opening flap under the windscreen. The car had load adjustable headlights and a heater (heaters were standardised on British economy cars in the 1960s).
The body was constructed of a dual H-frame platform chassis and aircraft-style tube framework, and a very thin steel shell that was bolted to the chassis.[98][99] Because the original design brief called for a low speed car, little or no attention was paid to aerodynamics; the body had a drag coefficient of Cd=0.51, high by today's standards but typical for the era.
The 2CV used the fixed-profile convertible, where the doors and upper side elements of its bodywork remain fixed although, the doors could be removed easily too by lifting them up and way from the car. The bonnet too could be removed by sliding sideways to allow extra ventilation on very hot
The 2CV used the fixed-profile convertible, where the doors and upper side elements of its bodywork remain fixed although, the doors could be removed easily too by lifting them up and way from the car. The bonnet too could be removed by sliding sideways to allow extra ventilation on very hot days. The fabric soft top can be rolled back and a picnic basket was available for purchase and fixed on the boot door. This reduces weight and lowers the centre of gravity, and allows the carrying of long or irregularly shaped items, but the key reason was that fabric was cheaper than steel which was in short supply and expensive after the war. The fixed-profile concept was quite popular in this period.[citation needed]
The suspension of the 2CV was very soft; a person could easily rock the car side to side dramatically. The swinging arm, fore-aft linked suspension system with inboard front brakes had a much smaller unsprung mass than existing coil spring or leaf spring designs. The design was modified by Marcel Chinon.[35]
The system comprises two suspension cylinders mounted horizontally on each side of the platform chassis. Inside the cylinders are two springs, one for each wheel, mounted at each end of the cylinder. The springs are connected to the front leading swinging arm and rear trailing swinging arm, that act like The system comprises two suspension cylinders mounted horizontally on each side of the platform chassis. Inside the cylinders are two springs, one for each wheel, mounted at each end of the cylinder. The springs are connected to the front leading swinging arm and rear trailing swinging arm, that act like bellcranks by pull rods (tie rods). These are connected to spring seating cups in the middle of the cylinder, each spring being compressed independently, against the ends of the cylinder.[35][100][101][102][100] Each cylinder is mounted using an additional set of springs, originally made from steel, called "volute" springs, on later models made from rubber. These allow the front and rear suspension to interconnect.[103] When the front wheel is deflected up over a bump, the front pull rod compresses the front spring inside the cylinder, against the front of the cylinder. This also compresses the front "volute" spring pulling the whole cylinder forwards. That action pulls the rear wheel down on the same side via the rear spring assembly and pull rod. When the rear wheel meets that bump a moment later, it does the same in reverse, keeping the car level front to rear. When both springs are compressed on one side when travelling around a bend, or front and rear wheels hit bumps simultaneously, the equal and opposite forces applied to the front and rear spring assemblies reduce the interconnection.[5][unreliable source?] It reduces pitching, which is a particular problem of soft car suspension.[5][unreliable source?]
The swinging arms are mounted with large bearings to "cross tubes" that run side to side across the chassis; combined with the effects of all-independent soft springing and excellent damping, keeps the road wheels in contact with the road surface and parallel to each other across the axles at high angles of body roll. A larger than conventional steering castor angle, ensures that the front wheels are closer to vertical than the rears, when cornering hard with a lot of body roll. The soft springing, long suspension travel and the use of leading and trailing arms means that as the body rolls during cornering the wheelbase on the outside of the corner increases while the wheelbase on the inside of the corner decreases. As the cornering forces put more of the car's weight on the outside pair of wheels the wheelbase extends in proportion, keeping the car's weight balance and centre of grip constant, promoting excellent road holding. The other key factor in the quality of its road holding is the very low and forward centre of gravity, provided by the position of the engine and transmission.[104]
The suspension also automatically accommodates differing payloads in the car- with four people and cargo on board the wheelbase increases by around 4 cm (2 in) as the suspension deflects, and the castor angle of the front wheels increases by as much as 8 degrees thus ensuring that ride quality, handling and road holding are almost unaffected by the additional weight.[105] On early cars friction dampers (like a dry version of a multi-plate clutch design) were fitted at the mountings of the front and rear swinging arms to the cross-tubes. Because the rear brakes were outboard, they had extra tuned mass dampers to damp wheel bounce from the extra unsprung mass. Later models had tuned mass dampers ("batteurs") at the front (because the leading arm had more inertia and "bump/thump" than the trailing arm), with hydraulic telescopic dampers / shock absorbers front and rear. The uprated hydraulic damping obviated the need for the rear inertia dampers.[106] It was designed to be a comfortable ride by matching the frequencies encountered in human bipedal motion.[8]
This suspension design ensured the road wheels followed ground contours underneath them closely, while insulating the vehicle from shocks, enabling the 2CV to be driven over a ploughed field without breaking any eggs, as its design brief required. More importantly it could comfortably and safely drive at reasonable speed, along the ill-maintained and war-damaged post-war French Routes Nationales. It was commonly driven "Pied au Plancher"—"foot to the floor" by their peasant owners.[5][107]
Citroën had developed expertise with front-wheel drive due to the pioneering Traction Avant, which was the first mass-produced steel monocoque front-wheel-drive car in the world. The 2CV was originally equipped with a sliding splined joint, and twin Hookes type universal joints on its driveshafts; later models used constant velocity joints and a sliding splined joint.[citation needed]
The gearbox was a four-speed manual transmission, an advanced feature on an inexpensive car at the time. The gear stick came horizontally out of the dashboard with the handle curved upwards. It had a strange shift pattern: the first was back on the left, the second and third were inline, and the fourth (or the S) could be engaged only by turning the lever to the rig
The gearbox was a four-speed manual transmission, an advanced feature on an inexpensive car at the time. The gear stick came horizontally out of the dashboard with the handle curved upwards. It had a strange shift pattern: the first was back on the left, the second and third were inline, and the fourth (or the S) could be engaged only by turning the lever to the right from the third. Reverse was opposite first. The idea was to put the most used gears opposite each other—for parking, first and reverse; for normal driving, second and third. This layout was adopted from the H-van's three-speed gearbox. Later models had an option for a semi-automatic clutch that allow the user to engage the first gear and wait at the traffic lights with the foot on the brakes only.[citation needed]
The windscreen wipers were powered by a purely mechanical system: a cable connected to the transmission; to reduce cost, this cable also powered the speedometer. The wipers' speed was therefore dependent on car speed. When the car was waiting at a crossroad, the wipers were not powered; thus, a handle under the speedometer allowed them to be operated by hand. The wipers and speedometer could not be used at the same time. From 1962, the wipers were powered by a single-speed electric motor. The car came with only a speedometer and an ammeter.[3][page needed]
The 2CV design predates the invention of disc brake, so 1948–1981 cars have drum brakes on all four wheels. In October 1981, front disc brakes w
The 2CV design predates the invention of disc brake, so 1948–1981 cars have drum brakes on all four wheels. In October 1981, front disc brakes were fitted.[61] Disc brake cars use green LHM fluid – a mineral oil – which is not compatible with standard glycol brake fluid.[108] The disc brakes were forced-air cooled by ducts drawing air from the engine fan housing, greatly reducing the likelihood of the brakes to overheat or fade in heavy use - especially during long descents in hot summer conditions in the Alps and other mountain regions.
The engine was designed by Walter Becchia and Lucien Gerard,[109][5][unreliable source?] with a nod to the classic BMW boxer motorcycle engine. It was an air-cooled, flat-twin, four-stroke, 375 cc engine with pushrod operated overhead valves and a hemispherical combustion chamber. The earliest model developed 9 PS (8.9 bhp; 6.6 kW) DIN. A 425 cc engine was introduced in 1955, followed in 1970 by a 602 cc one giving 28 bhp (21 kW) at 7000 rpm. With the 602 cc engine, the tax classification of the car changed so that it became a 3CV, but the name remained unchanged. A 435 cc engine was introduced at the same time to replace the 425 cc; the 435 cc engine car was named 2CV 4 while the 602 cc took the name 2CV 6 (a variant in Argentina took the name 3CV). The 602 cc engine evolved to the M28 33 bhp (25 kW) in 1970; this was the most powerful engine fitted to the 2CV. A new 602 cc giving 29 bhp (22 kW) at a slower 5,750 rpm was introduced in 1979. This engine was less powerful, and more efficient, allowing lower fuel consumption and better top speed, at the price of decreased acceleration. All 2CVs with the M28 engine can run on unleaded petrol.
The 2CV used the wasted spark ignition system for simplicity and reliability and had only speed-controlled ignition timing, no vacuum advance taking account of engine load.[110] The inlet and exhaust manifolds were welded together into a single unit, with exhaust pipe and inlet tract abutting each other directly under the carburettor at an enlarged 'heat chamber'. Heat from the exhaust warmed both the metal and the air/fuel mixture inside the chamber, ensuring full vaporization of the fuel for greater combustion efficiency. The chamber also served as a reservoir of fuel/air mixture downstream of the carburettor body, allowing each cylinder to draw an equal and balanced amount of mixture for further efficiency and smooth-running. The heat chamber principle was especially suitable for an engine running at Wide open throttle and heavy loads for long periods of time, as was intended for the 2CV, when the throttle plate in the carburettor would be fully open, the Manifold vacuum would be low and the exhaust temperatures would be high.
Unlike other air-cooled cars (such as the Volkswagen Beetle and the Fiat 500) the 2CV's engine had no thermostat valve in its oil system. The engine needed more time for oil to reach normal operating temperature in cold weather. All the oil passed through an oil cooler behind the fan and received the full cooling effect regardless of the ambient temperature. This removes the risk of overheating from a jammed thermostat that can afflict water- and air-cooled engines and the engine can withstand many hours of running under heavy load at high engine speeds even in hot weather. To prevent the engine running cool in cold weather (and to improve the output of the cabin heater) all 2CVs were supplied with a grille blind (canvas on early cars and a clip-on plastic item called a "muff" in the owner's handbook, on later ones) which blocked around half the aperture to reduce the flow of air to the engine.[citation needed] Like many other air-cooled car engines, the 2CV's oil sump was wide and shallow, being formed from extensions to the crankscase castings in the form of an inverted 'T'. The exterior of the sump was formed with cooling fins and the underside protruded below the level of the chassis rails, exposing the sump to the flow of air as the car drove along. The shape of the sump ensured that as much of the oil within as possible lay close to the cooled metal on the underside, further helping to regulate the oil temperature. As with the oil cooler, this cooling effect was unregulated and varied greatly depending on air temperature, vehicle speed and engine load.
The engine's design concentrated on the reduction of moving parts. The wasted spark ignition system for simplicity and reliability and had only speed-controlled ignition timing, no vacuum advance taking account of engine load.[110] The inlet and exhaust manifolds were welded together into a single unit, with exhaust pipe and inlet tract abutting each other directly under the carburettor at an enlarged 'heat chamber'. Heat from the exhaust warmed both the metal and the air/fuel mixture inside the chamber, ensuring full vaporization of the fuel for greater combustion efficiency. The chamber also served as a reservoir of fuel/air mixture downstream of the carburettor body, allowing each cylinder to draw an equal and balanced amount of mixture for further efficiency and smooth-running. The heat chamber principle was especially suitable for an engine running at Wide open throttle and heavy loads for long periods of time, as was intended for the 2CV, when the throttle plate in the carburettor would be fully open, the Manifold vacuum would be low and the exhaust temperatures would be high.
Unlike other air-cooled cars (such as the Volkswagen Beetle and the Fiat 500) the 2CV's engine had no thermostat valve in its oil system. The engine needed more time for oil to reach normal operating temperature in cold weather. All the oil passed through an oil cooler behind the fan and received the full cooling effect regardless of the ambient temperature. This removes the risk of overheating from a jammed thermostat that can afflict water- and air-cooled engines and the engine can withstand many hours of running under heavy load at high engine speeds even in hot weather. To prevent the engine running cool in cold weather (and to improve the output of the cabin heater) all 2CVs were supplied with a grille blind (canvas on early cars and a clip-on plastic item called a "muff" in the owner's handbook, on later ones) which blocked around half the aperture to reduce the flow of air to the engine.[citation needed] Like many other air-cooled car engines, the 2CV's oil sump was wide and shallow, being formed from extensions to the crankscase castings in the form of an inverted 'T'. The exterior of the sump was formed with cooling fins and the underside protruded below the level of the chassis rails, exposing the sump to the flow of air as the car drove along. The shape of the sump ensured that as much of the oil within as possible lay close to the cooled metal on the underside, further helping to regulate the oil temperature. As with the oil cooler, this cooling effect was unregulated and varied greatly depending on air temperature, vehicle speed and engine load.
The engine's design concentrated on the reduction of moving parts. The cooling fan and dynamo were built integrally with the one-piece crankshaft, removing the need for drive belts. The use of gaskets, seen as another potential weak point for failure and leaks, was also kept to a minimum. The cylinder heads are mated to the cylinder barrels by lapped joints with extremely fine tolerances, as are the two halves of the crankcase and other surface-to-surface joints.[citation needed]
As well as the close tolerances between parts, the engine's lack of gaskets was made possible by a unique crankcase ventilation system. On any 2-cylinder boxer engine such as the 2CV's, the volume of the crankcase reduces by the cubic capacity of the engine when the pistons move together. This, combined with the inevitable small amount of "leakage" of combustion gases past the pistons leads to a positive pressure in the crankcase which must be removed in the interests of engine efficiency and to prevent oil and gas leaks. The 2CV's engine has a combined engine "breather" and oil filler assembly which contains a series of rubber reed valves. These allow positive pressure to escape the crankcase (to the engine air intake to be recirculated) but close when the pressure in the crankcase drops as the pistons move apart. Because gases are expelled but not admitted this creates a slight vacuum in the crankcase so that any weak joint or failed seal causes air to be sucked in rather than allowing oil to leak out.[111]
As well as features intended for durability and efficiency, the early 2CV engines were also significantly under-tuned, making much less power than was theoretically possible. The original 375cc engine featured deliberately small-diameter inlet tracts and a small-diameter carburettor with conservative fuel jet sizes. This restricted both the engine's power output and its maximum rotational speed to far below the actual limits of its component parts, ensuring that however hard it was driven and despite extremes of temperature, it would not be close to its ultimate limits. The 375cc engine produced its 9 horsepower at 3500rpm and peak torque at 2000rpm. Many of the improvements in power output made to the 2CV engine over its production life were merely the result of removing the original in-built restrictions with more efficient carburettors, manifolds and valve events. The power peak speed was raised to 4200rpm for the 12.5 bhp (9.3 kW) 425cc engine from 1955, 4500rpm from 1962 and 5000rpm (18 bhp, 13 kW) from 1963. The new 602cc and 435cc engines introduced in 1970 made their power at 6750rpm - nearly double the speed of the original engine from 1948 but with very few changes to the engine's internal design or componentry. If the original 375cc engine had the same power density as the original 33 bhp (25 kW) 602cc version it would have produced 19 bhp (14 kW) - more than double its actual rated output. The original principle of deliberately restricting the engine's speed returned in 1979 for the revised M28 602cc engine, which had its carburettor and camshaft altered to make reduced power at a lower speed of 5750rpm in the interests of lower overall fuel consumption and better torque delivery. Even the most highly-tuned factory versions of the 2CV engine do not come close to the unit's actual upper limits - 2CVs used in the car's racing series use standard engines tuned to around 45 horsepower which still prove reliable even in long 24-hour endurance competitions.
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