Automotive Section 1 Vocab & Review

Chapter 1 - The Automobile

Where is the term Automobile derived from?

The term, “Automobile” is derived from the Greek word “autos,” which means self, and the French word mobile, which means “moving.”

Technology is used in the automotive industry how?

It’s an application of of math, science, physics, engineering, and other subjects.

What is another word for a part?

A part can also be referred to as a component.

What is a part or sometimes a component?

A part, sometimes called a component, is the most basic type of removable item on a car. A part can not be disassembled.

What is an electrical component?

An electrical component is a part in an electrical circuit or system.

What is an assembly?

An assembly is a set of fitted parts designed to complete a specific task.

Give an example of an assembly and why.

For example, the engine is an assembly that converts fuel into usable power to move the vehicle.

What do technicians often do with assemblies during service and repair operations?

Technicians must often take assemblies apart and put them back together during service and repair operations.

What is an automotive system?

An automotive system is a group of related components and assemblies that work together to preform a specific function (job or task).

Give an example of an automotive system:

For example, your vehicle’s steering system contains the steering wheel, steering shaft, steering gears, linkage rods, and other parts. These parts allow you to control the direction of the front wheels and tires for maneuvering (turning) your vehicle.

What are to two largest sections of a vehicle?

The frame and body are the two largest sections of a vehicle.

What is the frame?

The frame is the strong metal structure that provides a mounting place for all the other parts. The frame holds the holds the engine, transmission, suspension, steering, and other assemblies in position.

What is the body?

The body is a steel, aluminum, fiberglass, plastic, or composite (carbon fiber) skin forming the outside of the vehicle. The body is painted to give the vehicle an attractive appearance.

What is chassis?

The term chassis is often used when referring to a vehicle’s frame and everything mounted to it except the body; tires, wheels, suspension, brakes, engine, transmission, fuel tank, etc.

What is body-over-frame construction also known as?

Full-frame construction

What is body-over-frame construction or full-frame construction?

In body-over-frame construction or full-frame construction, the frame consists of thick steel members. The chassis parts and body bolt to the thick steel or aluminum frame. This heavy, strong design is used on some larger vehicles. Full-size trucks always use a full perimeter frame.

What happens in unibody construction?

With unibody construction, sheet metal body panels are welded together to form the body and frame. Also called unit-body construction or unitized construction, this is the common design used to build passenger cars. Unibody vehicles are generally lighter and more fuel efficient than body-over-frame vehicles and have a high strength-to-weight ratios.

What is vehicle curb weight?

vehicle curb weight is the total weight of the vehicle with a full tank of gas and no driver. Vehicle curb weights vary.

What has the highest vehicle curb weight?

Generally, pickup trucks and SUV’s are the heaviest vehicles and weigh about two and half tons.

What has the second highest vehicle curb weight?

Full-size cars, station wagons, and full-size vans weigh about two tons.

What has the a low vehicle curb weight?

Compact cars have a low curb weight of about 3,000 lb (1,360 kg).

What has the a lowest vehicle curb weight?

Small sports cars and micro cars are the lightest passenger vehicles, weighing in at about 2,000 lb (907 kg).

What is vehicle weight distribution?

Vehicle weight distribution is a measurement of how much force is pushing down on the front compared to the rear tires of the vehicle.

What is the ideal vehicle weight distribution?

An ideal weight distribution for economy and cornering ability (ability to turn a corner while maintaining directional stability) is 50/50 weight distribution can be found on many high-performance sports cars.

What is the vehicle weight distribution on a Front-wheel drive vehicle?

Front-wheel drive vehicles have about a 60% front and 40% rear weight distribution for good tire traction with the road surface.

What is a vehicle wheelbase?

Vehicle wheelbase is the distance from the centerline of the front wheels to the centerline of the rear wheels.

What is a typical wheelbase?

A typical wheelbase for a full-size car might be 100’’ (254cm) for a small, compact car and up to 150’’ (381cm) for a full-size pickup truck.

What is track width?

Track width is the distance between the centerlines of the two wheels on the same axle (right and left front wheels or left and right rear wheels). The trend is to make vehicles wider so they can corner more quickly without a roll over accident.

What is a typical track width?

A typical track width might be 62’’ (157 cm) at the front axle and 64’’ (163cm) at the rear axle.

What is vehicle length?

Vehicle length is a measurement from the outermost point on the front bumper to the outermost point on the rear bumper.

What is vehicle width?

Vehicle width is the distance between the two widest points from the right to the left sides of the body measured perpendicular to the vehicle’s centerline.

Explain the characteristics of a full-size car? (Vehicle size)

A full-size car is capable of carrying four or five adults. It usually has four doors and is rear- or all-wheel drive with a relatively large engine. Full-size cars are the heaviest passenger cars, but they still get slightly better gas mileage than most trucks and SUVs.

Explain the characteristics of a midsize car? (Vehicle size)

A midsize car is shorter and lighter than a full-size car, but it can still carry up to four adults comfortably. It often has a smaller engine and gets better fuel economy than full-size cars because of it’s reduced curb weight and frontal cross section.

Explain the characteristics of a compact car? (Vehicle size)

A compact car usually has front-wheel drive with a small 4- or 6-cylinder engine. Compact cars are generally very fuel-efficient because they are smaller and lighter than full-size and midsize cars.

Explain the characteristics of a minicompact car? (Vehicle size)

The minicompact car is the smallest car allowed on public roads. It often seats only two people. Its wheel-base is very short, and the diameter if its wheels and tires is normally smaller than that of other vehicles. Their low weight and tiny engine make the minicompact car one of the most fuel-efficient vehicles on the market.

What is the body type of a sedan?

A sedan is a car that has front and back seats and will carry four to six people. Both two-door and four-door sedans are available. They have center body pillars, or “B” pillars, between the front door and rear quarter panel.

What is the body type of a convertible?

A convertible has a roof panel that can be raised and lowered into a storage area behind the back seat. The convertible roof can be made of metal, a composite, or a synthetic fabric. A convertible has no door pillars, and its strength is designed into the center area of the frame or floor plan. Convertible are normally two-door models.

What is the body type of a hatchback, or liftback?

A hatchback, or liftback, has a large rear door for easy access when hauling items. Hatchbacks are available in three- and five-door models.

What is the body type of a station wagon?

A station wagon has a long, straight foor that extends all the way to the rear of the vehicle. Station wagons have large rear interior compartments and come in two- and four-door models.

What is the body type of a pickup truck?

A pickup truck is a front-engine, cab-forward vehicle with a large, open cargo area in the rear. Full-size pickups use a frame made of heavy gauge steel. The cab, bed, fenders, and other body panels are bolted to the frame. Rubber bushings fit between body panels and the frame to prevent noise and vibration from entering the passenger area.

What is the body type of a full-size van?

A full-size van has a large body for large families or commercial service. The minivan is midsize. It has a higher roofline for more headroom and cargo space. Most minivans are designed to carry seven passengers. They are usually front-wheel drive.

What is the body type of a sport-utility vehicle?

Sports-utility vehicles are often equipped with four-wheel drive systems and have a high roofline and floor pan. Because of the high floor pan, SUVs have ample ground clearance for off-road driving. They provide the comfort of a passenger car, the interior space of a station wagon, and the durability of a truck. Since an SUV is very heavy, with a complex heavy-duty four-wheel drive system, it is not as fuel efficient as other types of vehicles.

What is the body type of a crossover vehicle?

The crossover vehicle is a design mix. It is an SUV built on a passenger car chassis. The crossover is about half as tall as a minivan, which lowers its center of gravity for more rollover stability when cornering rapidly. The crossover also has a smaller cross section for improved aerodynamics.

What is fuel efficiency?

Fuel efficiency, or fuel economy, is a rating of how far a vehicle can travel on only one gallon of fuel (gasoline or diesel fuel). The EPA tests and rates cars to give them an average city and highway fuel economy rating. A typical fuel economy rating for a small economy car might be 40 miles per gallon (mpg) city and 43 mpg highway. Estimated city EPA fuel economy testing is done with a preset number of stops so the car has to accelerate to cruising speeds. Estimated highway EPA fuel economy ratings are for steady state interstate cruising speeds.

Explain the engine:

The engine provides the energy to propel (move) the vehicle and operate other vehicle systems. Most engines consume gasoline, gasohol, or diesel fuel. THe fuel burns inside the engine to produce heat. This heat causes hot gas expansion, creating high pressure inside the engine to move its parts and produce useful power.

Explain a four-stroke cycle:

Automotive engines normally use a four-stroke cycle. Four separate piston strokes (up or down movements) are needed to produce one cycle (compare series of events). The engine converts heat energy (burning fuel) into kinetic energy(spinning crankshaft).

Explain multi-cylinder engines:

Automotive engines are multi-cylinder engines, which means they have more than one piston and cylinder. Today’s vehicles can have 2-, 3-, 4-, 5-, 6-, 8-, 10-, or 12-cylinder engines. Additional cylinders generally increase engine size and power output, but they lower fuel economy. The industry trend is to smaller engines with 3 or 4 cylinders.

Explain computer systems:

The computer system uses electronic and electrical devices to monitor and operate various mechanical systems. Electronic controls are provided for the engine, drive train, suspension, instrumentation, restraint, and other systems. The use of computer systems has improved vehicle efficiency and dependability. Additionally, all onboard computers now have a powerful self-diagnostic capability. Today’s vehicle computers can troubleshoot every major assembly, circuit, component, and system almost instantly.

What are the three major sections of a car’s computer system:

Sensors, electronic, and actuators.

Explain sensors (car’s computer system):

sensors are input devices that produce or modify electrical signals with a change in a condition, such as motion, temperature, pressure, speed, location, etc. The sensors are the “eyes, ears, ad nose” of the computer control system.

Explain electronic control module (car’s computer system):

Electronic control module—The electronic control module (ECM) is a small computer (complex electronic circuits) that uses signals from input devices (sensors) to control various output devices (actuators). Each ECM serves as a “small brain” to determine needed outputs to actuators for the vehicle’s operating conditions.

Explain actuators (car’s computer system):

Actuators are output devices, such as small electric motors or electromagnets. They can move parts when energized by an electronic control module. The actuators serve as the “hands and arms” of the computer control system.

Explain modern car function:

A modern car can have several control molecules and dozens of sensors and actuators, all communicating (transferring data) with a main computer processor.

Explain a main computer processor:

A main computer processor is a larger, more complex control module (usually positioned under the dash) that can analyze electrical signals from smaller control modules wired into the vehicle’s network.

What do sensor or system module do when they detect an issue?

If any sensor system control module detects a problem, it will signal the main computer processor so it can turn on a dash warning light.

What is the fuel system?

A fuel system consists of the components that store fuel and deliver a combustible air-fuel mixture to the engine cylinders. The system introduces the correct amount of fuel into the cylinder for efficient combustion (burning) inside the engine.

What is air-fuel ratio?

The fuel the system must alter the air-fuel ratio (percentage of air and fuel) with changes in engine operating conditions (temperature, altitude, engine speed, load, and other variables).

What is a gasoline injection system?

A gasoline injection system meters fuel into the engine as needed. The engine control module reacts to electrical data from the engine sensors. It can then energize each fuel injector to spray fuel onto the intake valve or directly into the combustion chamber, depending on the type of injection system.

What does a throttle valve do?

A throttle valve controls airflow, engine speed, and engine power. When the gas pedal is depressed, the throttle valve is opened for more airflow into the cylinders. Because more air is brought into the engine, the computer must compensate by injecting more fuel, increasing engine power output. When the throttle valve is closed, the computer opens the injectors for only a small amount of time, making the engine run slowly at idle speed.

Explain the electrical system:

The vehicle’s electrical system consists of several subsystems (smaller circuits), including the ignition, starting, charging, and lighting systems. Each subsystem is designed to preform a specific task.

Explain the ignition system:

An ignition system is needed on gasoline engines to ignite the air-fuel mixture. It produces a high-voltage surge that jumps, or arcs, across the air gap at the spark plug tip at the correct time. This causes the air-fuel mixture to start to burn and expand in the combustion chamber.

Explain the starting system:

The starting system has a powerful electric starting motor. The starting motor rotates the engine’s crankshaft until the engine fires and runs on it’s own power. A battery provides the electricity for engine start-up. The driver turns the ignition key to the start position or presses an engine start button. Current then flows through the starting circuit to energize the starting motor. The starting motor then spins the crankshaft. As soon as the engine starts, the driver releases the key or button so the engine keeps running. With late-model cars, the engine computer de-energizes and disengages the starting motor as soon as the engine start its speed increases.

Explain the charging system:

The charging system is needed to replace electrical energy drawn from the battery. With a 12-volt battery, a belt-driven alternative (generator) forces electric current back into the battery when the engine is running. A voltage regulator, usually built into the alternator, controls the voltage and current output of the alternator.

Explain the lighting system:

The lighting system consists of a vehicle’s interior and exterior lights and all the components that operate them (fuses, wires, switches, relays, etc.). The exact circuit and part configuration vary from one make and model car to another. The exterior lights typically include the headlights, turn signals, brake lights, parking lights, backup lights, and side marker lights. The interior lights include the dome light, trunk light, the instrument panel lights, and other courtesy lights.

Explain cooling and lubrication systems:

The cooling and lubrication systems are designed to prevent engine damage and wear. They are vital systems that prevent the engine from self-destructing.

Explain the cooling system:

The cooling system maintains a constant engine operating temperature. It removes excess combustion heat to prevent engine damage and speeds warm-up of the engine. The water pump forces coolant (water and antifreeze solution) through the inside of the engine, hoses, and radiator. The coolant collects heat from the hot engine parts and carries it back to the back to the radiator. The radiator allows the coolant heat to transfer into the outside air. An engine fan draws cool air through the radiator. The thermostat controls coolant flow and engine temperature. It is usually located where the top radiator hose connects to the engine.

Explain the lubrication systems:

The lubrication system reduces friction and wear between internal engine parts. It circulates clean, filtered oil to high-friction points in the engine, such as bearings, camshift, crankshaft, and pistons. The lubrication system also helps cool the engine by carrying heat away from high-friction points between moving parts.

Explain the exhaust:

The exhaust system quiets the noise produced during engine operation and routes engine exhaust gases to the rear of the vehicle body.

Explain the emission control system:

Various emission control systems are used to reduce the amount of toxic (poisonous) substances produced by an engine and fuel system. Some systems prevent fuel vapors from entering the atmosphere (air surrounding the earth). Other emission control systems remove unburned and partially burned fuel from the engine exhaust.

Explain drive train:

The drive train transfers turning force from the engine crankshaft to the drive wheels. Drive train configurations vary, depending on vehicle design. The most common drive-train configurations are front-wheel drive, rear-wheel drive, and all-wheel drive.

Explain front-wheel drive:

Front-wheel drive is commonly found on smaller passenger cars. A front-wheel drive vehicle has superior traction on slippery roads because the weight of the engine and transaxle is directly above the drive wheels.

Explain rear-wheel drive:

The front-engine, rear-wheel drive configuration, is popular because the heavy engine is still in the front for safety. Front-wheel drive vehicles suffer from torque steer (steering wheel motion affected by driveline torque). For this reason, rear-wheel drive vehicles have more precise steering than front-wheel drive vehicles.