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51-501: The Ascari Ecosse is a mid-engined sports car produced by Ascari Cars from 1998 to 1999. It was the first production car released by the company and is essentially the production version of the Ascari FGT concept race car. In 1995 Ascari introduced the FGT at various European motor shows, designed by Lee Noble . It featured a 6.0 L mid-mounted Chevrolet fuel injected V8 engine . At

102-467: A drive shaft and placed the engine under the seat. This pioneering vehicle is now in the collection of the Smithsonian Institution . Mounting the engine in the middle instead of the front of the vehicle puts more weight over the rear tires, so they have more traction and provide more assistance to the front tires in braking the vehicle, with less chance of rear-wheel lockup and less chance of

153-422: A "two-tube" shock absorber, this device consists of two nested cylindrical tubes, an inner tube that is called the "working tube" or the "pressure tube", and an outer tube called the "reserve tube". At the bottom of the device on the inside is a compression valve or base valve. When the piston is forced up or down by bumps in the road, hydraulic fluid moves between different chambers via small holes or "orifices" in

204-456: A PSD shock absorber, which still consists of two nested tubes and still contains nitrogen gas, a set of grooves has been added to the pressure tube. These grooves allow the piston to move relatively freely in the middle range of travel (i.e., the most common street or highway use, called by engineers the "comfort zone") and to move with significantly less freedom in response to shifts to more irregular surfaces when upward and downward movement of

255-551: A complete disappearance of the "comfort vs. control" tradeoff, it also reduced pitch during vehicle braking and roll during turns. However, ASD shocks are usually only available as aftermarket changes to a vehicle and are only available from a limited number of manufacturers. Coilover shock absorbers are usually a kind of twin-tube gas charged shock absorber inside the helical road spring. They are common on motorcycles and scooter rear suspensions, and widely used on front and rear suspensions in cars. The principal design alternative to

306-502: A compression valve, whose role has been taken up by the dividing piston, and although it contains nitrogen gas, the gas in a mono-tube shock is under high pressure (260-360 p.s.i. or so) which can actually help it to support some of the vehicle's weight, something which no other shock absorber is designed to do. Mercedes became the first auto manufacturer to install mono-tube shocks as standard equipment on some of their cars starting in 1958. They were manufactured by Bilstein , patented

357-444: A correspondingly effective shock. The next phase in shock absorber evolution was the development of a shock absorber that could sense and respond to not just situational changes from "bumpy" to "smooth" but to individual bumps in the road in a near instantaneous reaction. This was achieved through a change in the design of the compression valve, and has been termed "acceleration sensitive damping" or "ASD". Not only does this result in

408-492: A front-engine or rear-engine car. When the engine is in front of the driver, but fully behind the front axle line, the layout is sometimes called a front mid-engine, rear-wheel-drive, or FMR layout instead of the less-specific term front-engine; and can be considered a subset of the latter. In-vehicle layout, FMR is substantially the same as FR, but handling differs as a result of the difference in weight distribution. Some vehicles could be classified as FR or FMR depending on

459-467: A great future for racing due to its light weight and easy fitment. One of the earliest hydraulic dampers to go into production was the Telesco Shock Absorber, exhibited at the 1912 Olympia Motor Show and marketed by Polyrhoe Carburettors Ltd. This contained a spring inside the telescopic unit like the pure spring type 'shock absorbers' mentioned above, but also oil and an internal valve so that

510-453: A problem in some cars, but this issue seems to have been largely solved in newer designs. For example, the Saleen S7 employs large engine-compartment vents on the sides and rear of the bodywork to help dissipate heat from its very high-output engine. Mid-engined cars are more dangerous than front-engined cars if the driver loses control - although this may be initially harder to provoke due to

561-405: A progressive and controllable manner as the tires lose traction. Super, sport, and race cars frequently have a mid-engined layout, as these vehicles' handling characteristics are more important than other requirements, such as usable space. In dedicated sports cars, a weight distribution of about 50% front and rear is frequently pursued, to optimise the vehicle's driving dynamics – a target that

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612-424: A skid or spin out. If the mid-engine vehicle is also rear-drive the added weight on the rear tires can also improve acceleration on slippery surfaces, providing much of the benefit of all-wheel-drive without the added weight and expense of all-wheel-drive components. The mid-engine layout makes ABS brakes and traction control systems work better, by providing them more traction to control. The mid-engine layout may make

663-401: A vehicle safer since an accident can occur if a vehicle cannot stay in its own lane around a curve or is unable to stop quickly enough. Mid-engine design is also a way to provide additional empty crush space in the front of the automobile between the bumper and the windshield, which can then be designed to absorb more of the impact force in a frontal collision in order to minimize penetration into

714-404: Is a dramatic reduction in "foaming" or "aeration", the undesirable outcome of a twin-tube overheating and failing which presents as foaming hydraulic fluid dripping out of the assembly. Twin-tube gas charged shock absorbers represent the vast majority of original modern vehicle suspension installations. Often abbreviated simply as "PSD", this design is another evolution of the twin-tube shock. In

765-419: Is a hydraulic shock absorber, which usually includes a piston, a cylinder, and an oil-filled chamber. The piston is connected to the piston rod, which extends into the cylinder and divides the cylinder into two parts. One chamber is filled with hydraulic oil, while the other chamber contains compressed oil or air. When there is an accident or vibration in the vehicle, the piston moves into the cylinder, forcing

816-505: Is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat ) which is then dissipated. Most shock absorbers are a form of dashpot (a damper which resists motion via viscous friction). Pneumatic and hydraulic shock absorbers are used in conjunction with cushions and springs. An automobile shock absorber contains spring-loaded check valves and orifices to control

867-508: Is compatible with electronic control. Primary among benefits cited in Multimatic ’s 2010 patent filing is the elimination of performance ambiguity associated with flexible shims, resulting in mathematically predictable, repeatable, and robust pressure-flow characteristics. An extra tube or container of oil connected to the oil compartment of the (main) shock via a flexible pipe (remote reservoir) or inflexible pipe (piggy-back shock). Increases

918-400: Is constantly evolving due to the continuous improvement of vehicle dynamics and passenger comfort. In common with carriages and railway locomotives, most early motor vehicles used leaf springs . One of the features of these springs was that the friction between the leaves offered a degree of damping, and in a 1912 review of vehicle suspension, the lack of this characteristic in helical springs

969-913: Is to damp spring oscillations. Shock absorbers use valving of oil and gasses to absorb excess energy from the springs. Spring rates are chosen by the manufacturer based on the weight of the vehicle, loaded and unloaded. Some people use shocks to modify spring rates but this is not the correct use. Along with hysteresis in the tire itself, they damp the energy stored in the motion of the unsprung weight up and down. Effective wheel bounce damping may require tuning shocks to an optimal resistance. Spring -based shock absorbers commonly use coil springs or leaf springs , though torsion bars are used in torsional shocks as well. Ideal springs alone, however, are not shock absorbers, as springs only store and do not dissipate or absorb energy. Vehicles typically employ both hydraulic shock absorbers and springs or torsion bars. In this combination, "shock absorber" refers specifically to

1020-408: Is typically only achievable by placing the engine somewhere between the front and rear axles. Usually, the term "mid-engine" has been primarily applied to cars having the engine located between the driver and the rear drive axles. This layout is referred to as rear mid-engine, rear-wheel drive , (or RMR) layout. The mechanical layout and packaging of an RMR car are substantially different from that of

1071-489: The Hartge 5.0 litre V8 engine based on the 4.4 L BMW unit. The new engine produced around 420 hp (426 PS; 313 kW) and 520 N⋅m (384 lb⋅ft) of torque. The last car was built at Blandford in 2000 with a sequential manual transmission and is still in possession of Ascari. The spaceframe chassis and wishbone suspension carry a lightweight fibreglass body, weighing 1,250 kg (2,756 lb). The Ecosse, with

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1122-592: The 1950s and 1960s, e.g. the AEC Reliance . The Ferrari Mondial is to date the only successful example of a true mid-engined convertible with seating for 4 and sports car/supercar performance. A version of the Lotus Evora with a removable roof panel is anticipated but no definite date is known. Like any layout where the engine is not front-mounted and facing the wind, the traditional "engine-behind-the-passengers" layout makes engine cooling more difficult. This has been

1173-602: The 1997 season, Ascari built 17 production versions of the FGT dubbed the Ecosse. The Ecosse was unveiled by Ascari at the 1999 Earls Court Motor Show. The Ecosse was given a BMW V8 engine in place of the Chevrolet and Ford units used in the FGT, although the engine was further tuned by Hartge . The 4.4 L engine produces around 300 hp (304 PS; 224 kW), while later larger 4.7 L units produced around 400 hp (406 PS; 298 kW). The last three cars were fitted with

1224-539: The Gabriel Snubber started being fitted in the late 1900s (also the similar Stromberg Anti-Shox). These used a belt coiled inside a device such that it freely wound in under the action of a coiled spring but met friction when drawn out. Gabriel Snubbers were fitted to an 11.9HP Arrol-Johnston car which broke the 6 hour Class B record at Brooklands in late 1912, and the Automator journal noted that this snubber might have

1275-437: The action of the auxiliary spring in the unit itself. The first production hydraulic dampers to act on the main leaf spring movement were probably those based on an original concept by Maurice Houdaille patented in 1908 and 1909. These used a lever arm which moved hydraulically damped vanes inside the unit. The main advantage over the friction disk dampers was that it would resist sudden movement but allow slow movement, whereas

1326-403: The car's debut season of 1995. The car also attempted to qualify for the 24 Hours of Le Mans , but was not fast enough to pass pre-qualifying. The car continued to maintain pace with newcomers to British GT Championship in 1996, before Zwart partnered with William Hewland, owner of Hewland engineering, for a partial season in 1997 with only a best finish of fourth at Donington Park . Following

1377-515: The case of the Ferrari FF taking power from both ends of the crankshaft with two separate gearboxes. These cars use a traditional engine layout between driver and rear drive axle. Typically, they're simply called MR; for mid-rear (engined), or mid-engine, rear-wheel-drive layout cars. These cars use mid-ship, four-wheel-drive , with an engine between the axles. These cars are "mid-ship engined" vehicles, but they use front-wheel drive , with

1428-414: The design and first appeared in 1954s. Because the design was patented, no other manufacturer could use it until 1971 when the patent expired. Spool valve dampers are characterized by the use of hollow cylindrical sleeves with machined-in oil passages as opposed to traditional conventional flexible discs or shims. Spool valving can be applied with monotube, twin-tube, or position-sensitive packaging, and

1479-419: The dissipated energy can be stored and used later. In general terms, shock absorbers help cushion vehicles on uneven roads and keep wheels in contact with the ground. In a vehicle, shock absorbers reduce the effect of traveling over rough ground, leading to improved ride quality and vehicle handling . While shock absorbers serve the purpose of limiting excessive suspension movement, their intended main purpose

1530-452: The engine in front of the driver. It is still treated as an FF layout, though, due to the engine's placement still being in the front of the car, contrary to the popular belief that the engine is placed in front of the rear axle with power transferred to the front wheels (an RMF layout). In most examples, the engine is longitudinally mounted rather than transversely as is common with FF cars. Shock absorber A shock absorber or damper

1581-413: The engine placed between the driver and the front axle. This layout, similar to the above FMR layout, with the engine between driver and the front axle, adds front-wheel drive to become a four-wheel drive. An engineering challenge with this layout is getting the power to the front wheels past the engine - this would normally involve raising the engine to allow a propshaft to pass under the engine, or in

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1632-551: The factory-installed engine (I4 vs I6). Historically most classical FR cars such as the Ford Models T and A would qualify as an FMR engine car. Additionally, the distinction between FR and FMR is a fluid one, depending on the degree of engine protrusion in front of the front axle line, as manufacturers mount engines as far back in the chassis as possible. Not all manufacturers use the Front-Mid designation. These cars are RWD cars with

1683-442: The flow of oil through an internal piston (see below). One design consideration, when designing or choosing a shock absorber, is where that energy will go. In most shock absorbers, energy is converted to heat inside the viscous fluid. In hydraulic cylinders , the hydraulic fluid heats up, while in air cylinders , the hot air is usually exhausted to the atmosphere. In other types of shock absorbers, such as electromagnetic types,

1734-439: The fore and aft weight distribution by other means, such as putting the engine in the front and the gearbox and battery in the rear of the vehicle. Another benefit comes when the heavy mass of the engine is located close to the back of the seats. It makes it easier for the suspension to absorb the force of bumps so the riders feel a smoother ride. But in sports cars, the engine position is once again used to increase performance and

1785-524: The hydraulic fluid through small holes, creating resistance and dissipating energy in the form of heat. This dampens oscillations, reducing further bouncing or wobble of the car. Shock construction requires a balance of features such as piston design, fluid viscosity, and overall size of the unit to ensure performance. As technology developed, other types of shock absorbers emerged, including gas and electric shock absorbers, that provided improved control and flexibility. The design and manufacture of shock absorbers

1836-430: The hydraulic piston that absorbs and dissipates vibration. Now, composite suspension systems are used mainly in 2 wheelers and also leaf springs are made up of composite material in 4 wheelers. Shock absorbers are an important part of car suspension designed to increase comfort, stability and overall safety. The shock absorber, produced with precision and engineering skills, has many important features. The most common type

1887-480: The larger 4.7 litre engine, can accelerate from 0–60 mph (0–97 km/h) in 4.1 seconds, while top speed is measured to be 200 mph (322 km/h). Only 17 were produced. The Ecosse was replaced by the Ascari KZ1 in 2003. Mid-engine design The mid-engine, rear-wheel-drive format can be considered the original layout of automobiles. A 1901 Autocar was the first gasoline-powered automobile to use

1938-419: The oil damped in the rebound direction. The Telesco unit was fitted at the rear end of the leaf spring, in place of the rear spring to chassis mount, so that it formed part of the springing system, albeit a hydraulically damped part. This layout was presumably selected as it was easy to apply to existing vehicles, but it meant the hydraulic damping was not applied to the action of the main leaf spring, but only to

1989-443: The passenger compartment of the vehicle. In most automobiles, and in sports cars especially, ideal car handling requires balanced traction between the front and rear wheels when cornering, in order to maximize the possible speed around curves without sliding out. This balance is harder to achieve when the heavy weight of the engine is located far to the front or far to the rear of the vehicle. Some automobile designs strive to balance

2040-414: The piston and via the valve, converting the "shock" energy into heat which must then be dissipated. Variously known as a "gas cell two-tube" or similarly named design, this variation represented a significant advancement over the basic twin-tube form. Its overall structure is very similar to the twin-tube, but a low-pressure charge of nitrogen gas is added to the reserve tube. The result of this alteration

2091-465: The piston starts to occur with greater intensity (i.e., on bumpy sections of roads— the stiffening gives the driver greater control of movement over the vehicle so its range on either side of the comfort zone is called the "control zone"). This advance allowed car designers to make a shock absorber tailored to specific makes and models of vehicles and to take into account a given vehicle's size and weight, its maneuverability, its horsepower, etc. in creating

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2142-536: The potentially smoother ride is usually more than offset by stiffer shock absorbers . This layout also allows the motor, gearbox, and differential to be bolted together as a single unit. Together with independent suspension on the driven wheels, this removes the need for the chassis to transfer engine torque reaction. The largest drawback of mid-engine cars is restricted rear or front (in the case of front-mid layouts) passenger space; consequently, most mid-engine vehicles are two-seat vehicles. The engine in effect pushes

2193-455: The pressure tube in response to changes in road smoothness. The two pistons also completely separate the shock's fluid and gas components. The mono-tube shock absorber is consistently a much longer overall design than the twin-tubes, making it difficult to mount in passenger cars designed for twin-tube shocks. However, unlike the twin-tubes, the mono-tube shock can be mounted either way— it does not have any directionality. It also does not have

2244-412: The rear passenger seats forward towards the front axle (if the engine is behind the driver). Exceptions typically involve larger vehicles of unusual length or height in which the passengers can share space between the axles with the engine, which can be between them or below them, as in some vans, large trucks, and buses. The mid-engine layout (with a horizontal engine) was common in single-decker buses in

2295-529: The rotary friction dampers tended to stick and then offer the same resistance regardless of speed of movement. There appears to have been little progress on commercialising the lever arm shock absorbers until after World War I , after which they came into widespread use, for example as standard equipment on the 1927 Ford Model A and manufactured by Houde Engineering Corporation of Buffalo, NY. Most vehicular shock absorbers are either twin-tube or mono-tube types with some variations on these themes. Also known as

2346-530: The same time as the launch of the car, Klaas Zwart, a Dutch racing driver expressed interest in the car and ended up buying the entire company along with the design rights of the car. The new owner of the company chose to enter the FGT in racing, the race car featured a Ford Modular V8 engine and was entered into the British GT Championship . With the sole car produced meeting the homologation requirements, Zwart won an event at Silverstone Circuit in

2397-526: The spring and vehicle combination bounced with a characteristic frequency, these auxiliary springs were designed with a different period, but were not a solution to the problem that the spring rebound after striking a bump could throw you out of your seat. What was called for was damping that operated on the rebound. Although C.L. Horock came up with a design in 1901 that had hydraulic damping, it worked in one direction only. It does not seem to have gone into production right away, whereas mechanical dampers such as

2448-412: The superior balance - and the car begins to spin. The moment of inertia about the center of gravity is low due to the concentration of mass between the axles (similar to standing in the middle of a playground roundabout, rather than at the edge) and the spin will occur suddenly, the car will rotate faster and it will be harder to recover from. Conversely, a front-engined car is more likely to break away in

2499-452: The twin-tube form has been the mono-tube shock absorber which was considered a revolutionary advancement when it appeared in the 1950s. As its name implies, the mono-tube shock, which is also a gas-pressurized shock and also comes in a coilover format, consists of only one tube, the pressure tube, though it has two pistons. These pistons are called the working piston and the dividing or floating piston, and they move in relative synchrony inside

2550-443: Was also fitted to many cars. One of the problems with motor cars was the large variation in sprung weight between lightly loaded and fully loaded, especially for the rear springs. When heavily loaded the springs could bottom out, and apart from fitting rubber 'bump stops', there were attempts to use heavy main springs with auxiliary springs to smooth the ride when lightly loaded, which were often called 'shock absorbers'. Realizing that

2601-533: Was the reason it was "impossible" to use them as main springs. However the amount of damping provided by leaf spring friction was limited and variable according to the conditions of the springs, and whether wet or dry. It also operated in both directions. Motorcycle front suspension adopted coil sprung Druid forks from about 1906, and similar designs later added Friction disk shock absorber rotary friction dampers, which damped both ways - but they were adjustable (e.g. 1924 Webb forks). These friction disk shock absorber s

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