- H -

H

Hydrogen An element with the atomic number of 1.

H-beam Rod

A connecting rod having an H-beam-shaped cross section.

H-shift Pattern

An arrangement of shift positions in the form of an H, for a manual transmission.

H-valve

An air-conditioning expansion valve used on some Chrysler and Ford car lines.

H/D

Heavy duty.

H/E

Hall-effect.

H/E-EIS

Hall-effect electric ignition system.

H2O

Water.

H2SO4

Sulfuric acid solution.

HAC

High air control or high altitude compensator.

Hack

1. A taxicab. 2. A passenger car for everyday driving. 3. To cut out a section of body work.

HADV

Heated air diverter system.

HAI

Hot air intake.

Hairpin

1. A turn greater than 90 degrees on a road or race course. 2. A crankshaft.

Half Duplex

A transmission mode that is bi-directional, but carries information in only one direction at a time.

Half Wave Rectification

The rectification of one-half of the AC voltage as in a DC genreator.

Half-cycle

When the voltage signal form an oxygen sensor crosses over a predetermined threshold. The predeterminer thresholds are the rich to lean switch points.

Half-moon Key

A term often used for Woodruff key.

Half-shafts

On either side of the differential that transmit power to the drive wheels.

Half-wave Rectifier

A rectifier that conducts current to the load only during one alternation of a cycle of ac voltage i.e.. an automotive generators out put is half-wave rectified.