Have you ever read an article about a new car
or spoken with a service advisor at a repair shop and ended up thinking to
yourself, “I need a translator to understand what he/she was talking
about!” You’re not alone. The automobile industry and repair providers
have their own unique vocabulary – a “language” that has added
literally hundreds of words over the last 20 years. Many of the new terms
involve electronic vehicle controls, wireless telematics capabilities,
sophisticated infotainment offerings and advanced driver assistance systems.
Below are a-lot of those terms.
If you ever have any questions, please feel
free to call Bridgewater Motorworks at 908.218.9100
A
Adaptive
cruise control (ACC): An advanced
cruise control system that maintains a preset distance or time interval from
the vehicle ahead by automatically controlling the brakes and throttle.
Adaptive
headlights: Headlights that steer
in the direction the front wheels are turned to improve visibility when going
around corners.
Advanced
Driver Assistance Systems (ADAS): A
variety of safety-related systems that monitor vehicle performance and the
surrounding environment. ADAS provide a variety of driver alerts when
potentially hazardous conditions exists, and some (such as automatic emergency
braking) can take corrective action if the driver fails to respond
appropriately to a dangerous situation.
Air
filter: A paper or fabric baffle that captures dust, dirt
and debris from the intake airstream to prevent it from entering the engine.
Aftermarket
part: Any service replacement part not obtained from the vehicle
manufacturer through a franchised dealer. Many aftermarket parts are made by
the same companies that supply the original equipment part to the vehicle
manufacturer.
All-wheel
drive (AWD): A permanent, four-wheel drive system designed
for improved traction on all surfaces and at all times. The main difference
between AWD and 4WD systems is that the driver cannot disengage AWD.
Anti-freeze
(coolant): The liquid in the engine cooling system that
dissipates heat. Engine coolant prevents freeze-up in winter, raises the
boiling point in summer, and protects the cooling system from rust and
corrosion year round.
Anti-lock
braking system (ABS): System that prevents wheel lock-up by
automatically regulating the brakes. ABS can decrease braking distances on
slippery pavement, prevent skidding and provide greater control during sudden
stops.
A-Pillar: The
roof support pillar at either side of the windshield.
Around view: A
series of cameras that provide an overhead 360-degree view of the area
immediately surrounding the vehicle via a screen on the dashboard.
Automatic emergency braking (AEB): A
system that automatically applies the brakes to prevent or mitigate a collision
when the car is approaching another vehicle or object at too high a rate of
speed.
Autonomous vehicle (AV): A car
that uses advanced technology to accelerate, brake and steer itself. There are
six levels of vehicle autonomy designated by SAE Standard J3016.
Autopilot:
The name Tesla uses for their semi-autonomous
vehicle driving system.
Axle
shaft: On front-wheel drive vehicles,
the shafts that connect the transaxle to the driven wheels. Axle shafts are
also used on some rear-wheel drive vehicles with independent suspensions to
connect the differential assembly to the driven wheels. Axle shafts commonly
have a universal joint at each end to accommodate suspension movement. In
front-wheel drive applications, constant velocity joints are used that smooth
power delivery and allow the wheels to be turned for steering.
B
Backfire:
Gunshot-like sound from the engine air intake or tailpipe.
Backlash: The
amount of free play between two moving parts. Commonly used in reference to the
clearance between two gears that mesh with one another.
Balancing
(tires): Adding small amounts of weight to a wheel to offset any
imbalance present in the tire and wheel assembly. Proper balance eliminates
wheel and tire vibrations that are annoying, can reduce traction in certain
circumstances and cause increased tire and suspension wear.
Battery: The component that
stores the electrical power needed to start the engine. The battery also powers
vehicle accessories when there is insufficient power output from the charging
system, and acts as a “shock absorber” for the vehicle electrical system.
Battery
acid (electrolyte): The fluid in automotive batteries, a mixture of
sulfuric acid and water.
Battery Electric Vehicle (BEV): A car
without an internal combustion engine that is powered exclusively by
electricity stored in a large onboard battery pack. Many BEVs, such as the
Nissan Leaf, have a driving range of about 60-100 miles. However, the Chevrolet
Bolt and all Tesla models have larger battery packs that offer driving ranges
of 140 to 300+ miles.
Battery
hold-down: A fastening device used to secure the battery firmly in
place. The two most common types are a wedge that clamps over a protrusion near
the bottom of the battery, or a bracket that fits around or across the top of
the battery and is secured with long threaded rods.
Bearing: a component that
reduces friction and wear between two moving parts. There are several types of
bearings. Engine crankshafts generally use plain bearings, while other rotating
components commonly use ball- or roller-bearings.
Biodiesel: Vegetable
oil- or animal fat-based diesel fuel. Biodiesel is typically blended with
petroleum-based diesel fuel in 5 or 20 percent concentrations that are commonly
referred to as B5 and B20.
Blind spot monitoring: An
ADAS system that monitors the driver’s blind spots at the rear quarters of the
car and provides audible, visual and/or tactile alerts when a vehicle is
present in them.
Bottoming: When
your vehicle reaches the limits of the suspension travel (such as when going
over bumps), and the vehicle’s springs are completely compressed. This results
in a sudden transfer of noise/harshness, particularly through the steering, and
possible contact of the vehicle undercarriage with the pavement.
B-Pillar: The
roof support pillars closest to the driver’s and front-seat passenger’s heads
at the rear of the front doors. “Hardtop” cars do not have B-pillars.
Brake Assist: An
ADAS system that automatically applies full braking power when it detects that
the driver is executing a panic stop.
Brake
booster: A vacuum or hydraulic powered
device that multiplies the foot pressure applied to the brake pedal to increase
braking power while reducing the required driver effort.
Brake
caliper: The hydraulic assembly that
contains the brake pads and applies them against the brake rotor to slow or
stop the car.
Brake
drag: Brakes that do not completely release after application.
Brake
drum: A cylindrical component that mounts on the wheel hub and
has a machined inner surface that the brake shoes press against to slow or stop
the vehicle.
Brake
fade: A loss of braking efficiency caused by high brake
temperatures. Fade typically occurs during extended and/or repeated heavy brake
usage. Brake fade requires increased pedal pressure to maintain the same level
of braking action. In extreme cases, the brake pedal may sink to the floor causing
a near total loss of braking ability.
Brake
fluid: The liquid in the brake system that acts as a hydraulic
fluid. As you step on the brake pedal, brake fluid is forced through the system
to apply the brake assemblies at the wheels.
Brake fluid reservoir: The
container that stores a supply of brake fluid until it is needed. On most
vehicles, the reservoir is mounted on the brake master cylinder.
Brake
master cylinder: The brake system component that turns the
mechanical power provided when you step on the brake pedal into the hydraulic
power that is needed to apply the brakes and slow or stop the vehicle.
Brake
rotor: A flat disc that mounts on the wheel hub and has machined
outer surfaces that the brake pads press against to slow or stop the vehicle.
Brake
shoes: Curved metal platforms faced
with a friction material that is pressed against the inside of a brake drum to
slow or stop the car. Brake shoes are applied by the wheel cylinder.
Brake
pads: Metal backing plates faced with a
friction material that is pressed against a brake rotor to slow or stop the car.
The brake pads fit into, and are applied by, brake calipers.
Bucking:
Engine miss or hesitation, or transmission slip then engagement, that causes
the car to lurch repeatedly as it accelerates.
Bushing: A
cylindrical metal sleeve with a hole through its center. Bushings are used to
guide and support various moving parts on automobiles. Bushings are often made
of bronze and, while sometimes lightly lubricated with oil or grease, depend
primarily on the strength and frictional properties of the metal itself for
durability.
C
Cabin: The
interior of the vehicle where the driver and passengers sit.
Camber: The
angle at which wheel and tire assembly tilts in (negative) or out (positive)
from vertical. Typically measured and adjusted as part of a wheel alignment.
Camshaft: A
machined shaft with eccentric lobes that are used to open the valves in the
engine cylinder head(s).
Caster: The
angle at which the kingpin axis of the vehicle suspension tilts forward
(negative) or rearward (positive) from vertical. Typically measured and
adjusted as part of a wheel alignment.
Catalytic
converter: An emission control
device in the exhaust system that uses chemical oxidation and reduction
processes to cleanse the engine exhaust gasses before they leave the tailpipe.
Chassis
(undercarriage): The vehicle framethat
carries all suspension and power train components. Most trucks still use a
frame that is separate from the body, but virtually all modern passenger cars
use unit-body construction in which the body itself serves as the main chassis
member.
Clutch: A
mechanism that can couple and uncouple two rotating parts. With manual
transmissions, a clutch between the engine and gearbox makes shifting easier
and allows the car to be brought to a stop with the engine running.
Cold
cranking amps (CCA): A rating that indicates the amount of power a
battery can provide for engine cranking in cold-start conditions.
Compressed Natural Gas (CNG): A
purified and pressurized version of natural gas suitable for use as an
automotive fuel. Most light-duty vehicles that can use CNG have a “bi-fuel”
system that allows operation on either gasoline or CNG.
Coolant
(anti-freeze): The liquid in the engine cooling system that
dissipates heat. Engine coolant prevents freeze-up in winter, raises the
boiling point in summer, and protects the cooling system from rust and
corrosion year round.
Coolant
recovery reservoir: A tank that stores additional engine coolant
and allows the radiator to be completely filled at all times for maximum
efficiency. As the engine warms up and the coolant expands, excess is directed
to the reservoir. As the engine cools and the coolant contracts, surplus in the
reservoir is drawn back into the radiator.
Compression
ratio: The ratio between the largest and smallest possible
volumes in the cylinder of an internal-combustion engine. For example, a
compression ratio of 9:1 means the piston will compress the air/fuel mixture
into a space that is nine times smaller than the maximum cylinder volume.
Constant
velocity (CV) joint: Typically used infront-wheel
drive applications, constant velocity joints are a form of universal joint that
smoothes power delivery and allows wheels to be turned for steering.
Continuously
Variable Transmission (CVT): an
automatic transmission that uses two variable-diameter pulleys and a steel belt
to continuously alter its gear ratio. This provides smooth power delivery and
allows the engine to operate at the optimum speed for any given driving
condition.
Control
arms: Pivoting suspension components that connect the vehicle
chassis to the spindle that supports the wheel and tire assembly.
Cowl: The
area on the vehicle body at the base of the windshield.
C-Pillar:
The roof support pillars at the sides of the rear
window. On four-door station wagons, the C-pillars are at the back of the rear
doors, and the pillars adjacent to the rear window become D-pillars.
Crank: The
car “cranks” when the starter motor is able to spin the engine or cause it to “turn
over.” If the car “will not crank” when you turn the ignition key, you hear
either a clicking sound, or nothing at all. The term “crank” is also used as a
short form of the word crankshaft.
Crankcase
(engine block): Largest assembly of an internal combustion engine.
Consists of the lower part of the engine, which contains the crankshaft,
connecting rods and pistons in an oil-tight housing.
Crankshaft: The central
machined shaft in an internal combustion engine. The crankshaft converts the
reciprocating motion of the pistons and connecting rods into rotary motion that
is directed to the transmission and ultimately to the wheels.
Curb
weight: The weight of a vehicle carrying a full tank of fuel but
no passengers or cargo.
Cuts
out:
When an engine loses power or misfires and feels like the engine is shut off
momentarily.
Crossover Utility Vehicle (CUV): A
vehicle similar to an SUV but built with unit-body construction (no separate
frame) and often based on existing passenger car structures. CUVs offer styling
similar to that of an SUV, but come in various sizes with fuel economy, ride
and handling more like a sedan than a truck. CUVs are typically used as
“people-haulers” and most have less off-road capabilities than more conventional
SUVs.
D
Daytime
Running Lights (DRL): Front lighting designed
to operate during daylight hours to improve a vehicle’s visibility to other
drivers. DRLs may be normal-intensity headlights, reduced-intensity headlights or
separate lighting assemblies that may include LED arrays.
Detonation
(knock, ping): Rapid, uncontrolled combustion of the air-fuel
mixture in the cylinder that results in a hard, rattling sound. Detonation can
cause severe engine damage if left unchecked for long.
Diesel (engine): An
engine design in which the fuel is ignited by heat generated in compressing air
rather than by a spark plug as in a gasoline engine. Diesel engines are more
efficient than gasoline engines, and provide more torque at lower rpm. Modern
“clean diesels” meet the same emission standards as gasoline engines and
require the use of ultra-low sulfur diesel (USLD) fuel, which has been mandated
for on-road diesels since 2007.
Dieseling: When
the engine continues to run for a short time after the ignition is turned off.
Caused by high combustion chamber temperatures igniting residual fuel drawn
into the cylinders. Usually occurs only on older carbureted engines.
Differential: A
system of gears that allows the outside driven wheel to rotate faster than the inside
driven wheel when turning a corner. Conventional “open” differentials direct
engine power to the wheel with the least traction, which can be a problem on
slippery surfaces. To combat this, some vehicles are equipped with
“limited-slip” differentials that ensure some power is always delivered to both
driven wheels.
Differential
lube (gear oil): Heavy-duty lubricant specifically designed to
handle the requirements of the gears and mechanisms located within the
differential case.
Dipstick: Calibrated
rod used to measure the level of a fluid. On automobiles, dipsticks are
commonly used to check the oil level in the engine, transmission and power
steering reservoir.
Disc
brake: Brake design in which brake pads press against a disc
(commonly called the brake rotor) to slow or stop the vehicle.
Driveability: An
assessment of vehicle operation that takes into account how well all systems
function and integrate with one another for a seamless driving experience. Most
commonly used in reference to powertrain operation across a wide range of
temperatures and load conditions.
Driver alertness monitoring: An
ADAS system that monitors driver behavior for indications of drowsy or
distracted driving. When warranted, the system provides visual and audible
alerts advising the drive to take make a rest stop.
Drivetrain (powertrain): The
combination of the engine, transmission, driveshaft, differential and axles
that deliver power to the wheels.
Drum
brake: Brake design in which brake shoes press against the inside
of a cylindrical drum to slow or stop the vehicle.
Drive
shaft: On rear-wheel or all-wheel drive vehicles, the shaft that
couples the transmission to the rear axle differential assembly.
Drive Pilot: The name Mercedes-Benz uses for their
semi-autonomous vehicle driving system.
Dual Clutch Transmission (DCT): An
automated manual transmission design that uses a pair of hydraulically-actuated
clutches to change between odd-numbered gears on one shaft and even-numbered
gears on another. See also Direct-shift Sequential Gearbox and Sequential Manual Gearbox.
Direct-shift Sequential Gearbox (DSG): An
automated manual transmission design that uses a pair of hydraulically-actuated
clutches to change between odd-numbered gears on one shaft and even-numbered
gears on another. See also Dual Clutch Transmission and Sequential Manual Gearbox.
Dual
overhead camshafts (DOHC): An engine with two camshafts located in
the upper portion of the cylinder head.
DUBs: A slang term for twenty-inch (“double dime”) or
larger custom wheels fitted with low profile tires for a custom look. Ride quality
can suffer with larger wheels and tires, although a low profile performance
tires may offer an improvement in handling (especially on dry roads) if its
diameter is close to that of the original equipment tire. Tires and wheels more
than an inch or two taller than stock can cause ride and handling to degrade
due to their increased weight.
E
Electronic
Control Module (ECM): A generic term
for an electronic module with computing power used to control vehicle systems.
Modern cars have multiple ECMs that communicate with one another over vehicle
networks.
Electrolyte
(battery acid): The fluid in automotive batteries, a mixture of
sulfuric acid and water.
Electronic brake force distribution (EBD): A
system that helps reduce stopping distances by using antilock brake system
components to vary front-to-rear braking force. The system compensates for
different vehicle loads, and normal weight transfer to the front axle during a
stop.
Electronic
fuel injection (EFI): A fuel delivery system in which electrically
controlled nozzles (injectors) spray fuel into the intake manifold or cylinders
as needed, allowing for more precise fuel control and better fuel efficiency
than can be achieved with a carburetor.
Electronic
Stability Control (ESC): A system that
provides selective wheel braking to improve vehicle handling and help drivers regain
control in certain extreme circumstances. ESC employs components of the
anti-lock braking system and is required on all passenger vehicles starting
with the 2012 model year. Systems on SUVs generally also provide incorporate
Rollover Mitigation.
Engine
block (crankcase): Largest assembly of an internal combustion engine.
Consists of the lower part of the engine that contains the crankshaft,
connecting rods and pistons in an oil-tight housing.
Ethanol: Ethyl alcohol sourced
primarily from corn that is blended with gasoline in varying proportions (E10,
E85, etc.) to reduce exhaust emissions from older vehicles while supporting
energy independence by reducing the need for imported oil.
Extended-Range Electric Vehicle (EREV): Similar
to a plug-in hybrid electric vehicle, an EREV has a much bigger battery that
typically provides an electric-only driving range of around 30 to 40 miles.
Once the battery is discharged, a gasoline engine powers a generator that gives
the vehicle an additional 200-300 miles of “extended-range” driving. Unlike a
PHEV, the gasoline engine in an EREV does not directly drive the vehicle; it
simply provides power to the battery, which continues to propel the car using
an electric motor. The Chevrolet Volt is an example of an EREV.
F
Fast
idle: An increased idle speed that typically occurs for a short
time after a cold engine start to improve drivability and speed engine warm up.
Flooding:
Excess fuel in the cylinders that makes starting difficult or impossible.
Forward
Collision Warning (FCW): A system that
provides the driver with an audible, visual and/or tactile alert when their
vehicle’s closing rate with the one ahead indicates a collision may be
imminent.
Four-wheel
drive (4WD or 4X4): A part-time system that powers all four wheels
for improved traction during adverse road conditions and off-road use. Four-wheel
drive systems differ from all-wheel drive (AWD) systems in two ways: they can
be disengaged when not in use, and they are not suitable for use on dry
pavement.
Front-wheel
drive (FWD): Drive system that provides power to only the
front wheels of the vehicle. Front-wheel drive systems incorporate a
differential into a transmission, creating a transaxle. A transaxle can be
automatic or manual shift.
Fuel
injection (FI): A fuel delivery system in which nozzles
(injectors) spray fuel into the intake manifold or cylinders, allowing for more
precise fuel control and better fuel efficiency than can be achieved with a carburetor.
Fuel injection systems come in a variety of forms, but virtually all modern
vehicles use some form of electronic fuel injection.
G
Gasoline Direct Injection (GDI): A fuel
delivery system that injects gasoline under extremely high pressure directly
into the engine combustion chamber. This technology generates more power with
better fuel economy and lower emissions.
Gear
oil (differential lube): Heavy-duty lubricant specifically
designed to handle the requirements of the gears and mechanisms located within
the differential case.
Grab:
Brakes engage suddenly and strongly, even when applying light pressure on the
brake pedal.
Green House Gas (GHG): Any
gas in the atmosphere that absorbs and emits radiation within the thermal
infrared range, thereby contributing to climate change/global warming. The
primary greenhouse gases in the Earth’s atmosphere are water vapor, carbon
dioxide, methane, nitrous oxide, and ozone.
Gross
Vehicle Weight Rating (GVWR): The
total maximum allowable weight capacity of a vehicle, including the weight of
the vehicle itself plus the weight of its fuel, passengers, and cargo.
Group
number: A number established by the Battery Council International
(BCI) that identifies a battery based on its battery length, height, width, terminal
design/location, and other physical characteristics. Not every battery has a
group number as some automakers use custom-sized batteries to fit the underhood
packaging requirements of their cars.
H
Hesitation:
Momentary loss of power on acceleration.
High Intensity Discharge (HID) headlights: Headlights
that use high voltage to ionize a mix of gases, including xenon, in a special
bulb to produce an extra-white or even bluish light that is several times
brighter than a conventional halogen headlight.
Highly
Automated Vehicle (HAV): The National
Highway Traffic Safety Administration term for autonomous vehicles that meet
Level 3 and higher performance requirements as specified in SAE Standard J3016.
Horsepower: The
measurement of the engine’s ability to produce work.
Hybrid Electric Vehicle (HEV): A
vehicle that achieves improved fuel efficiency by using an electric motor to
help the engine propel the car. The motor receives power from a modestly sized
battery that is automatically recharged during vehicle operation using a generator
driven by the car’s engine. The battery is also recharged by “regenerative
braking” that turns the electric motor into a generator during coasting and
braking. HEVs have no provision to connect an external charger, and the energy
contained in the battery can propel the vehicle under electrical power alone
for only a very short distance, if at all. The Toyota Prius is an example of an
HEV.
Hydrogen
fuel cell: An advanced “battery” that uses hydrogen and oxygen to
generate electricity that powers an electric motor to propel the car. The only
exhaust emissions of a hydrogen fuel cell are heat and water vapor.
I
Infotainment:
A
combined information and entertainment system that can incorporate audio, video
and various types of data from terrestrial radio, satellite radio,
CD/DVD/Blu-ray discs, SD cards, auxiliary inputs, a factory telematics system
and/or a Bluetooth link to a smartphone.
Intermittent:
A
problem that comes and goes with no obvious pattern.
K
Knock
(detonation, ping): Rapid, uncontrolled combustion of the air-fuel
mixture in the cylinder that results in a hard, rattling sound. Knock can cause
severe engine damage if left unchecked for long.
L
Lane departure warning (LDW): An
ADAS system that monitors lane markings and provides the driver with audible, visual
and/or tactile alerts if their car begins to leave its lane and the turn signal
is not on.
Lane keeping assist (LKA): An
ADAS system that automatically applies braking and/or steering inputs to help
keep a vehicle in its lane when the turn signal is not on.
Light Emitting Diode (LED) headlights:
Headlights that use an array of LEDs to provide forward illumination. LED
headlights provide a “whiter” light than HID units, but they are more
directional and may produce less light overall.
Lightweighting: The
process of reducing vehicle weight using high-strength steels, aluminum,
plastics, carbon fiber and other materials to achieve fuel economy gains that
reduce greenhouse gas emissions.
Limited-slip
(differential): A system of gears that allows the outside
driven wheel to rotate faster than the inside driven wheel when turning a
corner. Compared to a conventional “open” differential (which directs power to
the wheel with the least traction), a “limited-slip” differentials ensure that some
power is always delivered to both driven wheels.
Liquefied Petroleum Gas (LPG): Liquefied
petroleum gas, also called propane, is a combustible by-product of natural gas
processing and crude oil refining. LPG has been employed as a motor fuel for
over 90 years, and outside the U.S. it often goes by the name “autogas.”
M
Manual
transmission: A transmission that
requires the driver to change gears using a clutch and a shift lever.
Master
cylinder (brake): The component used to turn mechanical force
applied to the brake pedal into the hydraulic power needed to apply the brakes
and slow or stop the vehicle.
Master
cylinder (clutch): The component used to turn mechanical force
applied to the clutch pedal into the hydraulic power needed to release the
clutch and allow gear changing with a manual transmission.
Miles per gallon (MPG): A
measure of fuel efficiency based on the number of miles a vehicle can travel
using one gallon of fuel. Federal fuel economy estimates are based on
standardized tests that enable the use of EPA fuel economy estimates to compare
vehicles. See www.fueleconomy.gov.
Miles per gallon equivalent (MPGe): The
distance an electric vehicle can travel on the amount of energy equivalent to
that in a gallon of gasoline.
Misfire
(miss): The failure of the fuel charge in one or more engine
cylinders to ignite, or to ignite at the proper time.
Multi-point
injection: A fuel delivery system that utilizes a separate fuel
injector for each cylinder.
N
Night
vision: Systems that use active infrared lighting or passive
thermographic cameras to detect people, animals and other warm objects on or
adjacent to the road that are beyond what can be seen with the headlights. Obstacle
locations are displayed on a dashboard screen or projected onto the windshield
in front of the driver.
Noise,
vibration and harshness (NVH): An acronym used to discuss
various operational characteristics that affect perceived vehicle quality and
detract from the driving experience.
O
On Board Diagnostics (OBD-II): A built-in
diagnostic system on all 1996 and newer vehicles that monitors vehicle
emissions control systems for proper operation. Problems that cause an increase
in emissions will illuminate the “check engine” Malfunction Indicator Light
(MIL) on the dash. The OBD system also provides a standardized Diagnostic Link
Connector (DLC) for attaching diagnostic tools to the vehicle.
OE or
OEM: Original equipment or original
equipment manufacturer. Typically refers to components used to build the
vehicle at the factory, and available as service replacements through
franchised dealers.
P
Park
assist: A system of ultrasonic sensors
on the front and/or rear bumpers that provide the driver with audible, visual and/or
tactile alerts as their vehicle approaches a stationary object. Also, see self
parking.
Pilot
Assist: The name Volvo uses for their
semi-autonomous vehicle driving system.
Play:
Degree of “looseness” in a movable component or series of components. Often
used to describe suspension or steering wear. In the case of steering, play is
the amount of free movement at the steering wheel before the vehicle wheels
actually begin to turn.
Plug-in Hybrid Electric Vehicle (PHEV): Similar
to a conventional hybrid electric vehicle, a PHEV has a larger battery that can
be charged by plugging the car into an external power source. PHEVs have an
electric-only range of around 10-20 miles. Once that range is exhausted, the
vehicle reverts to normal hybrid operation with a gasoline engine that drives
the car and combines with regenerative braking to charge the battery for a
limited amount of electrical power assist. The Toyota Prius Plug-in is an
example of a PHEV.
Port
fuel injection: A fuel delivery system that uses a separate fuel
injector for each cylinder, and injects fuel into the intake ports upstream of
the intake valves.
Positive
crankcase ventilation (PCV) valve: Emission control system that
redirects crankcase vapors back into the engine to be burned. Often controlled
by a PCV valve that requires periodic replacement. PCV valve problems can cause
a car to run rough, stall, use excess engine oil, smoke, and have high exhaust emissions.
Power
loss: Engine runs at reduced speed or requires more throttle to
maintain constant speed.
Powertrain (drivetrain): The
combination of the engine, transmission, driveshaft, differential and axles
that deliver power to the wheels.
Preload: The
assembly of two components (often bearings) with a specified amount of pressure
between them so they are prepared to handle the loads that will be applied.
Pull: When
a vehicle self-steers to one side or the other when driving or braking.
R
Radiator: An
assembly of tubes and fins that transfer heat from the engine coolant into the
passing air stream. This process is aided by mechanical and/or electrical fans
that pull/push additional air through the radiator as needed.
Rain-sensing
wipers: Windshield wipers whose rate of
operation is electronically controlled based on the amount of moisture on the
windshield.
Rear cross
traffic detection: Sensors at the rear
of the vehicle detect approaching traffic or pedestrians when backing out of a
parking space. May be accompanied by or integrated with a rearview camera.
Rear
view camera: A camera mounted at
the back of the vehicle that displays a picture on a screen in the dash or rear
view mirror of what is behind the car when the transmission is in reverse.
Rear-wheel
drive (RWD or 4X2): A drive system that provides power to only the
rear wheels of the vehicle. In trucks, this type of powertrain is sometimes
referred to as “4X2” in comparison to a four-wheel drive “4X4” system.
Recall:
A safety- or emissions-related bulletin issued by
the vehicle manufacturer, the Environmental Protection Agency (EPA) or the
Department of Transportation (DOT). A recall involves work that must be done at
no charge to the consumer by an authorized dealer of the vehicle make involved.
Revolutions
per minute (RPM): The speed at which the engine crankshaft is
turning.
Ride: The quality
of the vehicle’s movement as it is driven down the road. Based on their
intended use, vehicles can have a variety of different ride characteristics. Factors
that affect a vehicle’s ride include the suspension, steering and brakes.
Rough
idle: When the engine vibrates or shakes while running with the driver’s
foot off the gas.
Rust
proofing: Protective coatings applied to vulnerable areas of a vehicle
to provide protection against moisture and road salts that cause rust and
corrosion. Tar-based products are typically used on exposed areas of the undercarriage,
while wax-based formulas are used on enclosed areas of the car body such as
doors and fenders.
S
Self
parking: A system that identifies potential parking spaces and
helps complete parking maneuvers. All such systems aid in parallel parking and
some can also perform pull-in and back-in parking. All of the systems control
steering, while some can also operate the accelerator, brakes and even
transmission forward and reverse gear selection.
Shift
quality: An assessment of how smoothly a transmission, manual or
automatic, changes gears.
Shimmy:
Side-to-side shaking in the suspension or steering.
Shock
absorber: Suspension component that damps spring oscillations. Shock
absorbers work by forcing a fluid through calibrated orifices that limit the
rate of movement. Some designs place the fluid under gas pressure to prevent or
reduce fluid foaming that can reduce shock absorber efficiency.
Sidewall: The
most visible part of the tire when viewing the vehicle from either side. The
sidewall contains information about the tire size, grade, and ratings as well
as the manufacturer’s name.
Single
overhead camshaft (SOHC): An engine with one camshaft located in
the upper portion of the cylinder head.
Sluggish:
Vehicle
does not accelerate smoothly or with authority.
Sequential Manual Gearbox (SMG): An
automated manual transmission design that uses a pair of hydraulically-actuated
clutches to change between odd-numbered gears on one shaft and even-numbered
gears on another. See also Dual Clutch Transmission and Direct-shift Sequential Gearbox.
Specific
gravity: Term used in connection with testing a battery’s
electrolyte. A specific gravity test is used to determine the battery’s state
of charge. Sealed “maintenance free” batteries sometimes have an indicator on
top that indicates the state of charge.
Spindle:
The suspension component on which the hubs, wheels
and tires mount and rotate. Spindles on the front suspension are turned side to
side to steer the vehicle.
Strut
(MacPherson strut): A type of shock absorber that also serves as a
suspension-locating member. Most struts incorporate the suspension spring
around their shaft, a design called the MacPherson strut. A “modified strut”
mounts the spring separately from the strut.
Stumble:
Engine begins to stall but then kicks back in.
Supplemental Restraint System (SRS): A
system of passenger protection air bags that supplement the conventional
seatbelts. Some modern cars have more than 10 airbags to protect occupants in
frontal, side and rollover crashes.
Sport Utility Vehicle (SUV): An
enclosed body on a truck chassis that provides ruggedness and ground clearance
with room for up to nine passengers and their cargo. These vehicles usually
have fuel economy and ride/handling traits similar to the trucks on which they
are based. The Chevrolet Tahoe/Suburban, GMC Yukon/Yukon XL and Ford
Expedition/Expedition EL are common SUVs.
Supercharger: An
engine driven compressor that forces additional air into the engine, allowing
more fuel to be burned for greater power output.
Surge:
Engine speeds up and slows down with no change in accelerator position or brake
application by the driver.
Suspension: The
combination of tires, wheels, hubs, spindles, control arms, springs, struts, shock
absorbers and related parts that support the chassis and body as the vehicle
moves down the road.
T
Technical
service bulletin (TSB): An advisory bulletin issued by a vehicle
manufacturer that describes updated processes and/or parts to address specific problems
that may occur on some models. Repairs based on a TSB are covered under a
new-car warranty. However, once the factory warranty has expired, TSB repairs
are performed at the owner’s expense in most cases.
Telematics: The
wireless transmission of useful information to and from a vehicle.
Thermostat: A
component that helps regulate engine temperature by controlling the speed at
which coolant circulates through the engine.
Tolerance: The
maximum size variation between two identical parts. Also, the allowable
variation in clearance between two closely-fit components.
Torque: Twisting
force produced by the engine.
Tow: The
angle at which the wheels on an axle point inward (tow-in) or outward (tow-out)
when the steering is pointed straight ahead. Typically measured and adjusted as
part of a wheel alignment.
Traction Control System (TCS): A
system that uses the anti-lock braking components to limit wheel spin when accelerating
on slippery surfaces. More advanced systems can also retard engine spark timing
and automatically back off the throttle when necessary to control wheel spin.
Transaxle: Used
in front-wheel drive and rear-engine, rear-wheel drive vehicles. Transaxles
incorporate both a transmission and a differential into a single unit.
Transverse
mounted engine: An engine mounted so that its crankshaft is
positioned side-to-side in relation to the vehicle. Transverse engines are typically
found in front-wheel drive vehicles.
Tread: The
pattern molded into area of the tire that contacts the road. The tread patterns
is designed to optimize traction based on the tire’s intended use.
Turbocharger: An
exhaust-driven supercharger that forces additional air into the engine,
allowing more fuel to be burned for greater power output.
Undercarriage
(chassis): The vehicle framethat
carries all suspension and power train components. Most trucks still use a
frame that is separate from the body, but virtually all modern passenger cars
use unit-body construction in which the body itself serves as the main chassis
member.
U
Universal
joint (U-joint): A mechanical coupler that allows a rotating
shaft to transmit power over a range of different angles.
V
Vacuum: The
lower than atmospheric pressure that exists in the intake manifold when the
engine is running. On most cars, engine vacuum is used to operate a variety of components
and systems.
Vacuum
hose: A hose (usually rubber or hard plastic) that transfers
vacuum to various vehicle components.
Variable Valve Timing (VVT): An
enhanced engine valve train control system used on most modern automobiles that
allows the lift, duration or timing (any or all) of the intake and/or exhaust
valves to be changed during engine operation. This technology provides smoother
operation, more power, better fuel economy and reduced exhaust emissions.
Vehicle Identification Number (VIN): A 17-character
“serial number” that is unique to each vehicle. The VIN characters are broken
down into several sections: the first 3 identify the manufacturer; the next 5
are vehicle attributes; check digit, model year and plant codes each have their
own single identifier; and the final 6 are the actual sequential number in the vehicle
production run.
Vehicle to Infrastructure (V2I): A
Dedicated Short Range Communications (DSRC) radio system that enables cars to
receive information from transponders on road signs, traffic signals and other
parts of the transportation infrastructure. Such signals could warn of speed
limits, traffic congestion, construction zones, underpass height limits and
more. V2I systems are currently under development.
Vehicle to Vehicle (V2V): A Dedicated
Short Range Communications (DSRC) radio system that enables nearby cars to
share information. This technology allows a vehicle to “know” what is happening
several cars ahead, and “see” events taking place outside the driver’s field of
view. V2V systems are currently under development.
Vehicle to X (V2X): A
“catch all” acronym used to describe V2I, V2V and other similar communication
systems.
Vehicle
Identification Number (VIN): The unique 17-character
identification number used to identify modern cars. In addition to the car’s
serial number, the VIN provides a variety of additional information about a
vehicle’s construction and components.
Viscosity:
The measure of a liquid’s ability to flow under
varying temperature conditions. In automobiles, viscosity most often refers to
the “weight” of motor oil, which is designated using number and letter grades
established by the Society of Automotive Engineers. Oils with low numbers such
as 5W or 10W flow easily at low temperatures (the “W” stands for winter). Oils
with high numbers such as 30 or 40 resist thinning at high temperatures. Most
modern engines call for multi-grade oils such as 5W-30 that perform well at
both low and high temperatures.
W
Water
pump: The pump that circulates coolant/antifreeze through the engine, radiator
and heater.
Wander:
Vehicle tendency to drift from side to side, requiring constant steering corrections
by the driver.
Wheelbase: The
distance between the centerlines of the front and rear axles of a vehicle.
Wheel
cylinder: The hydraulic component in a drum
brake assembly thatpresses the brake shoes against the drum to slow or stop
the car.
Wheel
(rim): What the tire is mounted on. Wheels can be made of steel
or a light alloy, such as aluminum.