DICTIONARY OF AUTOMOTIVE TERMS - "Im"

IM
Acronym for Inspection and Maintenance Programs
I/M
Acronym for Inspection and Maintenance
IMA
Acronym for Idle Mixture Adjuster
IMA sensor
idle mixture adjuster sensor
IMBA
Acronym for International Mountain Bicycling Association which is an organization dedicated to protect mountain bike trails
Imbalance
A lack of balance due to uneven weight distribution. Improper wheel balance due to uneven weight distribution on the tire and wheel assembly is one of the most common causes of vibration. When one side of the tire and wheel assembly is heavier than the other, centrifugal forces try to throw the heavy area outwards as the wheel turns.
Also See
dynamic imbalance
spin imbalance
wheel imbalance
IMCO
Acronym for improved combustion
IMEP
Acronym for indicated mean effective pressure
IMI
Acronym for institute of the Motor Industry, a British organization for managers in the motor industry
Immerse
To dip into or submerge in a liquid
Immersion treatment
See
tin immersion treatment
zinc immersion treatment
Immobile
A vehicle that is unable to move
Immobilize
To make immobile
Immobilizer
A device that makes something immobile (such as a Denver boot)
Impact
A sudden, hard, physical contact.
Also See
federal side impact standard
front-end impact
frontal impact
impact screwdriver
lateral impact
pendulum impact test
Impact absorber
An impact-damping element located between the bumper and bumper mounting to keep impact energy from being transferred into the car body
Impact adhesive
A contact glue that provides adhesion when two coated surfaces are pressed together
Impact air bag
See
side impact air bag
Impact bar
See
side impact bar
Impact break
A rupture to a tire resulting from the shock of striking a chuck-hole, rock, curb, etc. and not caused by cutting.
Impact cushion
Some child seats secure the child by an impact cushion in addition to the seat belt or straps
Impact damage
Damage that has been caused to the wall of a tire by contact with a curb or deep pothole, etc.
Impact driver
See
impact screwdriver
Impact dummy
See
side impact dummy
Impact intrusion beam
See
side impact intrusion beam
Impact pipe
A simplified version of an impact absorber
Impact resistance test
A determination of the resistance to breakage by flexural shock of plastics, as indicated by the energy extracted from "standardized" pendulum-type hammers, mounted in standard machines, in breaking standard specimens with one pendulum swing
Impact-resistant
Something that is stiffened (to a certain degree) to resist the force of a collision
Impact screwdriver
A tool which features a mechanism that converts the impact from a hammer into a powerful torque for loosening (or tightening) threaded fasteners. Also called "impact driver."
Impact sensor
An open switch that is designed to close when an crash occurs that is severe enough to warrant air bag deployment. See crash sensor
Impact socket
A heavy duty socket for use with air or electric power impact tools. Impact sockets are designed to stand up to the extreme stress of these tools and can be used in combination with special impact accessories such as extensions, universal joints, and adapters. These accessories are also designed to withstand the stress of air or electric power impact tools
Impact standard
See
federal side impact standard
Impact strength
The ability of a material to resist shock loading strain
Impact stress
The force per unit area imposed on a material by an abruptly applied force
Impact swivel ball universal joint
The swivel ball type universal joint is the most common type for use with impact sockets
Impact test
See
pendulum impact test
Impact wrench
A pneumatic or electric tool for use with impact sockets
Impedance (Z)
  1. Opposition in an electrical circuit to the flow of an alternating current that is similar to the electrical resistance to a direct current.
  2. The vectorial sum of both resistance and reactance in an electric motor; total opposition to current flow, measured in ohms. Z is the impedance symbol
  3. Any device that introduces electrical opposition in the form of resistance, reactance, or both.
Impeller
  1. A rotating member of a centrifugal pump which is equipped with vanes to convert mechanical energy into fluid energy. A rotor or wheel with blades or vanes used in pumps to drive and circulate fluid.
    Also See
    volute
  2. A fluid coupling or torque converter—the driving member connected to the crankshaft via drive plate and converter cover which generates the fluid flow inside the converter. The driving torus in the fluid coupling or torque converter of an automatic transmission.

Also See
bladed impeller
compressor impeller
mixed-flow impeller
vane wheel impeller
Impeller eye
The inlet area of an impeller in a pump
Impeller pump
A centrifugal and side-channel pump
Imperial

Imperial Books A vehicle brand of which the 1955-56 models are milestone cars.

Click image for books on Imperial

Imperial gallon
A quantity of 4.546 liters. Also called "UK gallon." It is 20% larger than a US gallon
Imperial phaeton
See
sport and Imperial phaeton
Imperial sedan
A drop or sliding glass partition between the driver's compartment and the tonneau is the distinguishing feature between this type and the sedan, which it resembles in all other respects.
Also See
sport and Imperial phaeton
Impermeable
Not capable of leaking fluid
Impervious
Not allowing gas to pass through
Import
See
captive import
Importer
An organization that typically operates at arms length or under contractual agreement with manufacturers to bring into the country products made in another country.
Import Measures Act
See
special Import Measures Act
Import nameplate
Vehicles sold by manufacturers primarily located outside North America whether assembled Overseas or in North America.
Improved recovery
Extraction of crude oil or natural gas by any method other than those that rely primarily on natural reservoir pressure, gas lift, or a system of pumps.
Improver
See
viscosity index improver
Impurities
Undesirable foreign material(s) in a pure substance or mixture.
IMRC
Acronym for Intake Manifold Runner Control (formerly IAC Intake Air Control) Controls variable inlet systems (VIS)
IMS
  1. Acronym for Ignition Module Signal
  2. Acronym for Inferred Mileage Sensor (Ford)
IMSA
Acronym for International Motorsports Association.
IMT
Acronym for Intake Manifold Timing