Terms Starting with R

 
R 134a-A hydro fluorocarbon gas that is not damaging to the environment and ozone layer that can be used in air conditioning systems.

Rack-and-pinion steering-A steering system consisting of a flat gear (rack) and a mating gear (pinion). The pinion meshes with teeth on the rack causing the rack to move left or right.  This motion moves tie-rods and the spindle arm to steer the front wheels of the vehicle.

Radial-Something that radiates from a center point.  Radial tires have cord material running in a direction from the center point of the tire, usually from bead to bead.

Radiation-Transferring heat energy to radiant energy.

RAM-Random access memory, or temporary storage of information in a computer.

Ram air-Air that is forced into the engine or passenger compartment by the force of the vehicle moving forward.

Reciprocating engine-An engine in which combustion pressures move parts up and down, or back and forth.

Rectify-To change one type of voltage to another.  For example, ac voltage is rectified to dc voltage in a battery charger.

Refrigerant-A liquid capable of vaporizing at low temperatures, such as ammonia or Freon.

Relay-An electromagnetic device which has low amperage in one circuit to operate a circuit or electrical device with higher amperage.  A cooling system relay is used to operate the electric fan.

Reluctor-In an electronic ignition system, a metal wheel with a series of points used to produce the signal for the transistor.

Residual pressure-Remaining or leftover pressure.

Resistance-The part in an electrical circuit called the load.

Resonator-A device used in an exhaust system to reduce noise, usually used in conjunction with the muffler.

Revolutions per minute (rpm)-The number of crankshaft revolutions occurring in an engine each minute.

Rich mixture-Too much fuel and not enough air for efficient combustion in the engine.

Road horsepower-Horsepower available at the drive wheels of the vehicle.

Rocker arm-An arm that has a pivot point in the center. One side is lifted by the camshaft lobe movement and the other side moves down to open the valves.

Rolling resistance-A term used to describe the amount of resistance a tire has as it's rolling on the road.  Tires that have lower rolling resistance usually get better fuel mileage.  Radial tires have lower rolling resistance.

ROM-Read only memory or permanent storage of information in a computer.

Rope seals-A type of seal used on crankshafts shaped much like a small thin rope to seal oil inside the engine.

RTV sealants-A type of sealant that is able to cure in the presence of moisture and oxygen.

Rust inhibitors-A type of chemical put into cooling and fuel systems to prevent rust from forming in the liquid.


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