Dictionary of Automotive Terms Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS - "Hy"

Hybrid: An alternative power plant that combines a small internal combustion engine and an electric motor to get maximum power with minimum emissions and maximum fuel economy.

Hybrid car: A car with a Hybrid propulsion system. See Hybrid Vehicle

Hybrid-Electric Vehicle: (HEV) A vehicle that is powered by two or more energy sources, one of which is electricity. HEVs may combine the engine and fuel system of a conventional vehicle with the batteries and electric motor of an electric vehicle in a single drivetrain.

Hybrid pad sets: Brake pad sets that contain an organic pad for one side of the rotor, and a semi-metallic pad for the other

Hybrid propulsion: Two distinct but interdependent forms of propulsion, such as an electric motor and an internal combustion engine, or an electric motor with battery and fuel cells for energy storage, or pedal power and an electric motor.

Hybrid technology: Film circuits combined with integrated circuits, used especially for trigger boxes or electronic control units

Hybrid transmission line: A double-circuit line that has one alternating current and one direct circuit. The AC circuit usually serves local loads along the line.

Hybrid Vehicle

A vehicle that uses two or more forms of Propulsion. Some examples are the following

Hybrid Vehicles
Cadillac Escalade Hybrid	Chevrolet Malibu Hybrid	Chevrolet Tahoe Hybrid	Ford Escape Hybrid
GMC Yukon Hybrid	Honda Civic Hybrid	Lexus GS 450h	Lexus LS 600h L
Lexus RX 400h	Mercury Mariner Hybrid	Nissan Altima Hybrid	Saturn Aura Green Line
Saturn Vue Green Line	Toyota Camry Hybrid	Toyota Highlander Hybrid	Toyota Prius

Also see
Electric Hybrid Vehicle

HydraAir: A Rock_Shox® suspension design that uses air springs, negative springs (coil), and an oil bath.

Hydra_Coil: A Rock_Shox® suspension design that uses coil springs, negative springs (coil), and an oil bath.

Hydragas: See
Moulton Hydragas suspension

Hydragas suspension: See
Hydropneumatic suspension
Moulton Hydragas suspension

Hydrates: See
Natural Gas Hydrates

Hydration Pack: Hydration Pack

A water filled back pack for cyclists and hikers. It has a tube placed within reach for supplying water for the user. Trade names are Camelbak® and Hydrapak®

Hydraulic

When a quantity of water, oil, or other fluid is forced along one end of a line, it also forces against the other end of the line. Because these fluids (unlike a gas) cannot be compressed, when they are forced into a smaller Cylinder they multiply the amount of force. Thus a Driver can apply a small amount of force on the pedal or lever and a great amount of force is applied to the brake. Used in Power steering, Clutches, and Brake systems.
When used as a verb, it means that oil or excessive Gasoline has entered the Combustion chamber so that when Compression takes place, the fluid cannot be compressed. Something has to give and it is usually the Connecting rod that bends. It is found in the expression, the engine hydrauliced.

Hydraulic accumulator: A part of the hydraulic system which is charged by the fluid pump, absorbs fluctuating fluid delivery, stores fluid at pressure, and can provide a rapid flow of fluid under pressure.

Hydraulic actuator: Unit in an anti-lock brake system that can increase brake pressure, decrease brake pressure, or hold brake pressure steady based on signals it receives from the control module

Hydraulic actuators: The hydraulically operated struts which control the movement of the wheels in an active ride suspension system

Hydraulically-activated brakes: A motorcycle system where the brakes use hydraulic fluid instead of a cable. When the lever/pedal is squeezed/pressed, hydraulic fluid forces the pistons to put pressure on the brake pads which rub against the brake disc and cause enough friction to stop the bike. A master cylinder that contains the hydraulic fluid sits on the handlebar near the brake lever.

Hydraulically-assisted brakes: See
Brake booster.

Hydraulically-activated clutch: Found in a motorcycle, the clutch is engaged/disengaged via hydraulic fluid instead of a cable. When the lever is squeezed, hydraulic fluid forces the pushrod to disengage the clutch. A master cylinder that contains the hydraulic fluid sits on the handlebar near the clutch lever.

Hydraulically-assisted clutch: A clutch operated by hydraulic pressure.

Hydraulically operated power booster: A power booster that uses hydraulic pressure to assist the driver in the application of the brakes. This hydraulic pressure usually comes from the power steering pump or an electro-hydraulic pump

Hydraulic assisted brakes: See
Brake booster.

Hydraulic booster: A master cylinder containing a separate hydraulic chamber and Spool valve operated by power steering fluid. Hydraulic pressure in the booster pressure chamber operates the master cylinder piston.

Hydraulic brakes: See
Brake booster
Froude Hydraulic Brake

Hydraulic brake booster: Click image to supersize

Hydraulic pressure supplied by the power steering pump, or a separate hydraulic pump, which is used to assist in applying the brakes; used on cars and on some trucks

Hydraulic Brake Power-assist Unit: See
Air Hydraulic Brake Power-assist Unit

Hydraulic assisted brakes: Brakes operated by hydraulic pressure.

Also See
Brake booster.

Hydraulic brake system: A brake system in which brake operation and control utilizes hydraulic pressure.
Also see
Air-assisted Hydraulic Brake System
Manual Hydraulic Brake System
Split Hydraulic Brake System
Vacuum Over Hydraulic Brake System

Hydraulic braking system: Brakes operated by hydraulic pressure.

Also See
Air-assisted hydraulic brake system

Hydraulic circuit

Part of the main brake system that includes two of the four wheel brakes and operates independently of the other two wheel brakes; all vehicles have a primary and secondary hydraulic circuit
The path of hydraulic fluid from the master cylinder to the wheels, through all valves, lines, hoses, and fittings.

Hydraulic control block: A Control valve assembly

Hydraulic control unit: The portion of an anti-lock brake system that houses the solenoid valves and electro-hydraulic pump

Hydraulic-Electronic Unit Injector: (HEUI) A type of unit injector actuated by engine oil pressure rather than the camshaft. A very high oil pressure (up to 3,000 psi) is created by a separate oil pump. This high pressure is routed to every injector through a gallery. The engine's Electronic Control Module varies the pressure in response to engine speed and other parameters.

Hydraulic fluid: A special oil used in hydraulic systems, such as power steering, self-leveling suspension, to operate the system of master and slave cylinders. Also compare Brake fluid and Automatic transmission fluid

Hydraulic fracturing: Fracturing of rock at depth with fluid pressure. Hydraulic fracturing at depth may be accomplished by pumping water into a well at very high pressures. Under natural conditions, vapor pressure may rise high enough to cause fracturing in a process known as hydrothermal brecciation.

Hydraulic hoist: Hydraulic hoist

A device for lifting a vehicle from the ground. Usually found in service bays to facilitate inspection of the running gear and exhaust system or for removing fluids.

Hydraulic hood: British term for Hydraulic top

Hydraulic jack: A device used to lift a vehicle by using hydraulic pressure.

Hydraulic lift: A device used in a service garage to raise a vehicle so that a mechanic can look at or repair components under the vehicle.

Hydraulic lifter: See
Hydraulic valve lifter.

Hydraulic modulator: A device which regulates hydraulic fluid pressure in an ABS.
Also See
Hydraulic control unit

Hydraulic piston: A piston in a cylinder, acted upon by or acting on a hydraulic fluid.

Hydraulic Power Unit: See
Vacuum Hydraulic Power Unit

Hydraulic pressure: The force per unit area exerted in all parts of a hydraulic system by a liquid.

Hydraulic pressure pump: An engine-driven pump which supplies oil under pressure to operate, e.g., power brakes or power-assisted steering

Hydraulic Retarder: A transmission-mounted hydraulic device which assists in slowing down a vehicle. See Retarder

Hydraulics

Branch of physics having to do with the mechanical properties of water and other liquids in motion.
The study of pressure and flow in liquids. A Hydraulic jack uses oil under high pressure to lift large objects more easily.

Hydraulic service bench: Bench equipment used when disassembling, assembling, and testing brake calipers.

Hydraulic tappet: British term for Hydraulic valve lifter

Hydraulic top: A convertible top which is raised and lowered by a hydraulic system; depending on engineering, a hydraulic top can operate fast, silently, and with tremendous power.

Also See
Power top
Tensile force

Hydraulic valve lifter: A Lifter that uses Hydraulic oil pressure to maintain no Clearance between metal parts so that valve noise is reduced. Also it reduces wear on the valves and eliminates periodic valve adjustments.

Hydraulic wedge: A Hydraulic jack with ends designed to reach behind dented double panels and to press them back into shape by the hydraulic action of the wedge-shaped ends

Hydraulique Minerale: See
Liquide Hydraulique Minérale

Hydride: See
Nickel Metal Hydride

Hydroactive suspension: See
Hydropneumatic suspension

Hydrocarbon: (HC) A Compound made up of hydrogen and Carbon (e.g., Gasoline, Petroleum products, etc.). Hydrocarbons are also found when gasoline is burned in an engine and thus produce visible Smog even though hydrocarbons make up only 0.1% of emissions.
Also See
Paraffinic Hydrocarbons
Polynuclear Aromatic Hydrocarbons
Total hydrocarbons
Unburnt hydrocarbons

Hydrocarbon engine: An engine using Petroleum products, such as gas, liquefied gas, Gasoline, kerosene, or fuel oil as a fuel.

Hydrocarbon plastics: Plastics based on resins made by the polymerization of monomers composed of carbon and hydrogen only

Hydrocarbons: Organic compounds containing only hydrogen and carbon atoms in various combinations.

Hydrochlorofluorocarbon: (HCFC) Chemicals composed of one or more carbon atoms and varying numbers of hydrogen, chlorine, and fluorine atoms.

Hydrocracking: See
Catalytic hydrocracking

Hydrodynamic clutch: See
Fluid coupling

Hydrodynamic torque converter: See
Torque converter

Hydroelectric power: See
Hydro-electric power.

Hydro-electric power: Electricity produced by using the Kinetic energy of water.

Hydrofluorocarbon: (HFC) A group of man-made chemicals composed of one or two carbon atoms and varying numbers of hydrogen and fluorine atoms. Most HFCs have 100-year Global Warming Potentials in the thousands.

Hydrofoil: A vessel which skims the surface of the water and the shaped pieces on the bottom of the vessel which act like water wings to give it lift.

Hydrogen: (H) A gas formed of the single element hydrogen. It is considered one of the most active gases. When combined with oxygen, it forms a very clean flame which, however, does not produce a very high temperature or very much heat.

Hydrogen embrittlement: A process which results in a decrease of the toughness or ductility of a metal due to absorption of hydrogen

Hydrolastic: See
Moulton Hydrolastic suspension

Hydrolastic suspension: A proprietary suspension system incorporating a conical rubber spring compressed by hydraulic pressure; this system also provides a hydraulic interconnection between front and rear wheels on one side of the vehicle.

Also See
Moulton Hydrolastic suspension

Hydromechanical Injection: An injection system in which mechanical parts work through hydraulic pressure to meter and time the injection of fuel. No electronics are incorporated into hydromechanical injection systems.

Hydrometer

Floating instrument used to measure specific gravity of a liquid.
A device to determine the weight of a liquid. It is used to test Battery Electrolyte and the percentage of Coolant in the Cooling system.

Also see
Beck Hydrometer

Hydronic: Heating system which circulates a heated fluid. usually water, through baseboard coils by means of a circulating pump which is controlled by a thermostat.

Hydroplane

When your tires start to float on top of water, causing them to lose contact with the road's surface
When a tire rolls upon a layer of water instead of staying in contact with the pavement. Hydroplaning occurs when all of the water on the pavement cannot be displaced from under the tire tread.

Hydroplaning: Hydroplaning

A phenomenon of driving when water builds up under the Tire tread, causing it to lose contact with the road. Caused by speed, water depth, tread depth, and inflation pressure. Slowing down will usually restore normal tire contact with the road. Also called Aquaplaning.

Hydropneumatic suspension: A Suspension system which uses a gas and a liquid which are separated by a flexible Bladder. The setup causes the Suspension to maintain a preset height. Used in Citroën cars.

Hydropulser: A hydraulically operated system that can excite vibrations of various frequencies in a car; serves to find and eliminate noise sources

Hydrostatically inflate: To inflate with water instead of air.

Also See
Liquid ballast

Hydrostatic drive: See
Hydrostatic transmission

Hydrostatic gauge: Gauges, such as gas tank gauge, in which the depth of the gas in the tank controls the air in the connecting line to the instrument, which registers the depth on a scale or dial

Hydrostatic steering: A power steering system without mechanical steering links, but is controlled entirely by hydraulics

Hydrostatic test: Pressure test using water

Hydrostatic transmission: A drive by means of hydraulic motors, particularly where the drive is to each wheel of an off-road vehicle

Hydrotreating: See
Catalytic hydrotreating.

Hydroxyl radical: (OH) An important chemical scavenger of many trace gases in the atmosphere that are greenhouse gases. Atmospheric concentrations of OH affect the atmospheric lifetimes of greenhouse gases, their abundance, and, ultimately, the effect they have on climate.

Hygrometer: Instrument used to measure degree of moisture in the atmosphere.

Also See
Absorption hygrometer
Wet Bulb Hygrometer

Hygroscopic

Something that tends to absorb moisture
Ability of a substance to absorb and release moisture and change physical dimensions as its moisture content changes.

Hypoid axle: A driving axle with a hypoid gear

Hypoid gear: Hypoid gear

A type of Spiral bevel gear in which the Drive pinion shaft is located below the center of the Ring gear. This setup is used to lower the height of the Driveshaft and thus lower the floor of the vehicle.

Hypoid oil: A special lubricant for hypoid gears

Hysteresis

The energy lost and not returned, when tire materials are subjected to stress in any direction. Lost energy is converted to heat through molecular interaction, and since rubber has poor thermal conductivity, internal temperatures of a tire can build up rapidly under repeated flexing.
The damping provided by Elastomer springs.

hysteresis loss: The resistance offered by materials to becoming magnetized, reduced by using silicon steel laminations

Hyundai: Click image for books on
Hyundai

An automobile manufactured in South Korea which includes Accent (1995-2008), Azera (2006-07), Elantra (1992-2008), Entourage (2007), Excel (1985-94), Santa Fe (2001-07), Scoupe (1991-95), Sonata (1989-08), Tiburon (1997-2007), Tucson (2005-07), Veracruz (2007), XG300 (2001), and XG350 (2002-05)