Vehicle Classifications Quiz

Vehicle Classifications

• A vehicle is a machine used for transporting passengers or goods.
• Wheeled motor vehicles move on wheels, applying steering and traction forces against the ground.
• Common examples are cars, trucks, buses, and motorcycles.
• This study focuses on passenger cars.
• EU general classification of wheeled motor vehicles:
  • Category M: Motor vehicles with at least four wheels designed and constructed for the carriage of passengers.
    • M1: Vehicles for passenger carriage with no more than eight seats, including the driver's seat.
    • M2: Vehicles for passenger carriage with more than eight seats, and a maximum mass not exceeding 5 tons.
  • Category N: Motor vehicles with at least four wheels designed and constructed for the carriage of goods.
    • N1: Light commercial vehicles for goods transport with a maximum mass not exceeding 3.5 tons.
    • N2: Large goods vehicles for goods transport with a maximum mass exceeding 3.5 tons but not exceeding 12 tons.
  • Category L: Two-wheel vehicles (motorcycles), and quadricycles.
    • L3e: Motorcycles without a sidecar with an engine capacity over 50 cm³ and a maximum design speed over 45 km/h.
    • L6e: Quadricycles with an unloaded weight not exceeding 350 kg (excluding batteries in case of electric vehicles), a maximum design speed not exceeding 45 km/h, and an engine cylinder capacity not exceeding 50 cm³ for spark ignition engines, or a maximum net power output not exceeding 4 kW for other internal combustion engines, or a maximum continuous rated power not exceeding 4 kW for an electric motor.

Passenger Car Categorization

• Passenger cars don't have formal categories beyond Category M1.
• Categorization is based on comparison to well-known models, e.g., Volkswagen Golf might be in the Ford Focus size class.
• Common passenger car segments include mini cars (A), small cars (B), medium cars (C), large cars (D), executive cars (E), and luxury cars (F).
• Additional segments include sport coupés (S), multi-purpose cars (M), and sport utility cars (J).

Chassis and Body Overview

• Chassis is the base frame of the vehicle.
• Components like engine, transmission, suspensions, controlling systems (braking, steering), and electrical parts are mounted on the chassis.
• The chassis is the main mounting for all components, including the body, which acts as a carrying unit.
• During a crash, the chassis must provide maximum protection for passengers, with high torsional and bending rigidity.
• Body refers to the outside shell of the vehicle.
• The bodywork aims to offer comfortable accommodation for the driver and passengers, suitable protection from weather, and an attractive design that appeals to customers.
• Vehicle bodies need to be practical for entering and exiting, with ease of reaching controls.

Most Common Chassis-Body Types

• Unibody (unitized body): A single, integrated structure of chassis and body.
• Offers superior crash protection.
• High volume manufacturing is cost-effective but high initial investment for large molds makes it less feasible for small-scale production.
• Examples include passenger cars, SUVs, and light commercial vehicles.

Conventional Unibody

• Constructed from hollow sheet-steel tubes. Metal panels are welded onto the tubes.
• Approximately 5000 spot welds.

Ladder Chassis

• Simplest and oldest chassis design, with two beams and cross-members.
• Simple and robust; offers low torsional rigidity to weight ratio.
• Often made from steel.
• Preferred for heavy-duty commercial vehicles (trucks, buses, off-road vehicles).

Space Frame Chassis

• Lightweight rigid structure constructed from struts in a geometric pattern.
• Tubes can be curved, resulting in high torsional and bending rigidity to weight ratio.
• Suitable for race cars, sports cars, and special-purpose vehicles.
• High manufacturing costs often hinder use in mass production.

Body and Chassis Materials

• Sheet steel (various alloys) is the most common material for chassis and body structures, 0.6-3.0 mm thick.
• Steel offers strength, ductility, and cost efficiency, but is heavier.
• Aluminum is also used to reduce weight, commonly in extruded sections and sheet components.
• Fiber glass (glass reinforced plastics) is lightweight and often used for bodies of sport cars.
• Carbon fiber offers the best strength to weight ratio, but high cost hinders widespread use.
• Thermoplastics are frequently used for separate body components (bumper, spoiler, etc.) due to cost efficiency and resistance to corrosion.

Body Surface

• Corrosion is a major problem for body surfaces, particularly in metal components.
• Rust (oxidation of iron) weakens metal components.
• Solutions for controlling corrosion include pre-coating steel components (e.g., galvanization, hot-dip galvanization)

Galvanization

• Process of applying a protective zinc coating to steel to prevent rust.
• Hot-dip galvanization is a common method where steel parts are submerged in molten zinc.
• Often followed by painting to prevent corrosion.

Geometrical Design

• Some geometrical design modifications contribute to corrosion reduction.
• Flanged joints, minimized sharp corners, and open ventilation must be considered.

Aerodynamics

• Automotive aerodynamics reduces drag force, wind noise, and prevents lift force.
• For racing cars and sports cars, downforce is also important to enhance road holding.
• Key factor in drag is pressure variations caused by the vehicle moving through air.

Drag Area

• Cd. A is the fundamental parameter for aerodynamic resistance.
• Calculated from the vehicle's body shape and size.
• Cd (drag coefficient) is separately evaluated.

Vehicle Collisions and Safety

• Vehicle collisions are a significant cause of injury and death.
• Active safety technologies aim to prevent crashes, such as good visibility from the driver's seat, low interior noise level, good handling and road holding.
• Modern active safety systems include Anti-Lock Braking System (ABS)
• Electronic Stability Control (ESC)
• Traction Control System (TCS)

Collision Avoidance

• Sensors that place warnings to prevent or reduce impact force.

Crashworthiness

• The science of minimizing injuries and fatalities in vehicle collisions.
• Chassis must satisfy 5 basic requirements: Maintain Survival Space, Restrain the Occupants, Prevent Ejection, Transfer Energy and Prevent Fire.

Crumple Zones

• Parts designed to displace and absorb energy from a collision, reducing force on occupants. Positioned at front, rear and occasionally side of the vehicle.

Passive Safety Equipment

• Seatbelts, airbags, head restraints, and interior padding reduce impact forces during a crash.

Crash Testing

• Destructive testing of vehicle to ensure safety standards according to scientific and safety standards.

Suspension Systems Overview

• Suspension systems aim to maximize tire-to-road contact area.
• This enhances road holding, steering stability, and ride comfort.

Suspension Components

• Springs: Resist vehicle weight and absorb road shocks (important aspects of suspension performance).
• Damper: slow down oscillations caused by the spring system, and transform kinetic energy caused by motion into hydraulic heat energy

Spring Types

• Leaf Spring: Multi layered metal "leaves"
• Coil Spring: Wound into a spiral.
• Torsional Spring: A steel rod treated with heat/pressure to absorb rotational forces.

Anti-Roll Bar

• Used to prevent vehicle body from rolling during high lateral acceleration in turns.

Control Arms and Joints

• These linkages of the suspension mechanism, control how the wheels move according to their kinematic requirements.
• Made usually from sheet-steel, metal or alloys.
• Spherical and revolute joints.

Suspension Kinematics

• The most important kinematic parameters affecting driving performance are: -Camber angle: the tilt of the wheels, -Caster angle: affects steering, -Kingpin angle: directs steering, -Toe angle: wheel alignment in the forward direction.

Wheelbase and Trackwidth

• Wheelbase: Distance between the centers of the front and rear axles.
• Trackwidth: Distance between the centers of the left and right wheels.

Sprung and Unsprung Masses

• Sprung mass: includes a vehicle's body, frame, motor, and transmission which the springs support.
• Unsprung mass: includes the wheels, brakes, half of the control arm's weight

Suspension Types

• Dependent (rigid axle) and independent suspensions. Dependent systems link wheels together (their movement affects each other) while Independent systems allow wheels to move independently.

Steering Systems Overview

• Steering is a collection of components involved in controlling the vehicle's direction of motion.

Basic Steering Methods

• Differential steering on tanks and some specialized vehicles.
• Articulated steering on heavy machinery (a hinged chassis).
• Fifth-wheel steering, used for towed vehicles.
• Ackerman steering (a crucial geometric arrangement for proper turning radius) is also noted.

Steering Components

• Steering wheel
• Steering column
• Steering gear (e.g., rack and pinion)
• Power steering (hydraulic or electric)

Turning Radius

• Turning radius is the radius of the arc described by the center of the wheel during the shortest turn. Using Ackerman steering is shown

Tires and Wheels

• Tires are continuous bands with treads that roll on the ground, road surface, or prepared tracks.
• Two main types: Steel (e.g., railroad vehicles) & Rubber.
• Pneumatic tires (with air) are more common for cushioning.

Pneumatic Tire Properties

• Comfortable ride
• Good steering
• Stability in drive/cornering
• Durability and wear resistance
• Economical wear

Rolling Resistance

• Resistance when a tire rolls on a flat surface.
• Depends on numerous factors: tire material, wheel radius, surface adhesion, forward speed

Tire Codes

• Tires are identified by alphanumeric codes, often molded into the sidewall, containing standardized information like Speed Rating, Load Index, Rim Diameter, Construction type, and Intended Vehicle class

Drivetrain Configurations

• Rear-wheel drive
• Front-wheel drive
• All-wheel drive

Components of a Drive Train

• Energy Supplying Device: (battery, electric motor, or muscular exertion),
• Control Devices: (pedal, lever, or sensors)
• Transmission Devices: (gears, chains, and belts).

Clutches

• The clutch is a part of transmission that connects and disconnects the engine from the drive train.
• Dry plate friction clutch: with a pressure plate, clutch disk, bonded/riveted friction surfaces, and a flywheel
• Wet plate friction clutch: Immersed in lubricating fluid to assist heat dissipation

Torque Converters

• Converts engine's mechanical energy into hydraulic energy.
• Helps transmission multiply or increase torque at low speed ranges

Transmissions Overview

• Transmissions convert torque and rotational speed.
• Allow for forward and reverse motion, adapting to wheel speed variations in turns (curves).

Manual Transmissions

• This involves switching gears manually, typically using a gear shifter.
• Two main Types: Sliding mesh gearboxes, Constant mesh gearboxes

Automatic Transmissions

• Hydraulic automatic transmissions have an automatic gear shift mechanism
• Includes components: hydrodynamic torque converter (initiates motion & torque multiplication), planetary gear sets (different gear ratios), hydraulic pump (pressurizes hydraulic system), and transmission control system (for automatic gear selection)

Automated Manual Transmissions

• Use a combination of manual and automatic components for the gear shifting process. For instance, electro-hydraulic systems utilize electronic sensors, actuators and processors to maintain the appropriate timing

Dual Clutch Transmission

• Has two sets of clutches for the odd and even gearsets. Helps avoid the lengthy gear change delays of a manual transmission

Continuously Variable Transmissions (CVTs)

• Provides a continuous range of gear ratios without discrete steps.

Hydrostatic Transmissions

• Transmits power hydraulically; commonly used in heavy machinery(e.g., excavators)

Electric Transmissions

• Converts engine power to electricity using electric generators and converts this electricity to mechanical power again using electric motors.

Differentials and Drive Shafts

• Differentials are devices that enable the drive shafts to rotate at different speeds, necessary for turning.

Drive Shaft Joints

• Cardan joint (Hooke's joint) is a spatial mechanism for transmitting rotary motions to different axes. Allows for a variable angle.
• Constant velocity joints (CV joints) are two types: Rzeppa and Double-Cardan joints. These maintain consistent output shaft speed even with a variable angle.

This list provides a comprehensive summary, encompassing various aspects of a vehicle's components, their workings, and the different types available. Further details are often necessary for a deeper understanding of each specific component within a vehicle.

Test your knowledge on vehicle classifications, focusing on passenger cars and the EU's vehicle categories. This quiz covers definitions, categories, and examples of wheeled motor vehicles, including distinctions between types of passenger and commercial vehicles.