Rack-and-Pinion Steering
A rack and pinion is a pair of gears which convert rotational motion into linear motion. The circular pinion engages teeth on a flat bar - the rack. Rotational motion applied to the pinion will cause the rack to move to the side, up to the limit of its travel. |
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Radial Tire
Tire design which uses body cords running at right angles to the center line of the tire. Two or more belts are used to give tread strength. Radials can be identified by their characteristic sidewall bulge. |
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Radiator
At highway speeds, airflow helps cool the radiator. However, at low speeds or when idling, a Radiator Fan helps provide the air flow needed to reduce coolant temperatures. The radiator fan is an essential part of a car's cooling system.
:: Click for detailed Radiator information |
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Rain Sensor
Using infrared technology, it recognises drops of water on the windscreen and adjusts the speed of the windscreen wiper to suit the intensity of the rain. In heavier rainfall or when accelerating to pass a long vehicle, for example, the windscreen wipers automatically increase in pace to ensure unimpeded vision. Additional light sensors in the windscreen detect changes in light conditions - e.g. at dusk or when entering a tunnel - and automatically turn on the dipped-beam headlights. |
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Rear Window Defroster
A device which features small wires placed on the rear window. When this device is switched on, electrical current passing through the wires causes a small amount of heat to clear the window of frost or fog. |
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Refrigerant
The substance used in an air conditioning system. It absorbs the heat as it changes from liquid to gas in the evaporator, then gives up the heat as it changes back to a liquid in the condenser. Freon 12 is a common automotive refrigerant. |
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Relay
A relay is an electrical switch that opens and closes under control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835.
:: Click for detailed Relay information |
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Resonance Intake Manifold
Boxer engines and V-type engines (but not inline engines) may employ resonance intake manifold to boost mid to high rev efficiency.
Each bank of cylinders are fed by a common plenum chamber through separate pipes. The two plenum chambers are interconnected by two pipes of different diameters. One of the pipes can be closed by a valve controlled by engine management system.
:: Click for detailed Resonance Intake Manifold information |
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Resonator
A small auxiliary muffler that assists the main muffler in reducing exhaust noise. |
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Roll-over Protection
A safe "occupant cell" should the vehicle overturn. Roll-over sensors activate special high-strength roll-bars that are integrated in or behind the seats, ensuring there is sufficient clearance for occupant's heads in the event of an accident. The integrated seatbelt system ensures that you and your passenger are restrained firmly in your seats. |
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Rolling Resistance
This is motion-resisting force that is present from the instant the wheels begin to turn. On normal road surfaces, rolling resistance decreases with increased tire pressure, and it increases with vehicle weight. Rolling resistance can also be affected by tire construction and tread design. |
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RPM
Revolutions Per Minute. A unit of measure for angular speed. As applied to the IC (Internal Combustion) engine, rpm indicates the instantaneous rotational speed of the crankshaft described as the number of crank revolutions that would occur every minute if that instantaneous speed was held constant throughout the measurement period. Typical idle speeds are 300 to 800rpm, while peak engine speeds can reach as high as 10,000rpm or higher in some racing engines. |
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Run-Flat Tyre
Thanks to special side-wall reinforcement, run-flat tyres are capable of being driven long distances even after a puncture. The need for a spare tyre is eliminated, reducing weight and freeing boot space on every single journey.
:: Click for detailed Run-Flat Tyre information |
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