月: 2023年2月

What Is a Clutch?

A clutch is a power transmission device that connects the engine to the transmission in vehicles. It plays a vital role in managing the transfer of engine power to the transmission and is essential for starting, stopping, and shifting gears in cars and motorcycles. The clutch ensures smooth transitions and prevents the harsh impact that would otherwise occur during gear shifts. While often associated with manual transmission vehicles, automatic transmission vehicles also utilize a torque converter, which functions similarly to a clutch.

Principle of Clutches

The clutch system comprises the flywheel, clutch disc, and clutch cover. The flywheel connects directly to the engine, transmitting its rotational motion. The clutch disc, attached to the transmission, engages with the flywheel when the clutch pedal is depressed, transferring the engine’s rotation to the transmission and then to the wheels. The clutch cover encases these components and supports the engagement and disengagement process through a pressure plate.

Uses of Clutches

Clutches are used not only in automobiles and motorcycles but also in various other applications requiring power transmission, such as electric motors, lawnmowers, snowplows, helicopters, and ships.

Types of Clutches

Clutches can be classified based on their construction and operation.

1. Dog Clutch

This type of clutch features interlocking teeth or claws for direct power transmission without loss. However, it’s unsuitable for vehicles with large RPM differences between the engine and transmission.

2. Friction Clutch

Friction clutches use the force of friction for power transmission, making them suitable for smooth transmission in vehicles. They can be further categorized into disc and drum types, with variations like wet and dry clutches, multi-plate clutches, electric friction clutches, and centrifugal clutches.

3. Hydraulic Clutch

Hydraulic clutches transmit power through a liquid medium. A notable advancement in this category is the torque converter, commonly used in automatic transmission vehicles.

Other Information on Clutches

Why Is a Half Clutch Necessary?

The ‘half clutch’ technique is essential in manual transmission vehicles for smooth gear shifting and starting. It involves gradually engaging the clutch to smoothly transfer engine power, preventing the jarring shocks that would occur with sudden engagement.

What Is a Suspension?

A suspension is a crucial component in vehicles that connects the tires to the car body. It significantly influences ride quality by reducing the impact from road surfaces and maintaining the vehicle’s stability. The balance between driving stability and ride comfort can be adjusted based on the suspension settings. While commonly associated with cars and motorcycles, the term suspension also applies to vibration-absorbing mechanisms in various machines and equipment.

Uses of Suspensions

All automobiles and motorcycles are equipped with suspensions, as they connect the body and tires. Suspensions are also used in trains, tanks, bicycles, furniture, buildings, and wherever there is a need to soften and absorb impacts.

Principle of Suspensions

Suspensions typically consist of springs, shock absorbers, suspension arms, bushings, and upper mounts. Springs cushion tire impacts, while shock absorbers dampen the springs’ vertical movement, reducing impact transmission to the vehicle body. The hardness and dimensions of suspension components can be adjusted to modulate shock mitigation.

Types of Suspensions

Suspensions are categorized into fixed-axle and independent types.

1. Fixed Axle

This suspension type connects the wheels on both sides with an axle. It is known for its simplicity, durability, easy maintenance, and low cost. However, it has the drawback of transmitting shocks from one wheel to the other. Fixed-axle suspensions are mainly used in commercial vehicles such as trucks and SUVs.

2. Independent Suspension System

In this system, each wheel is connected to separate axles, reducing cross-wheel impact transmission and improving ride comfort. Independent suspensions are prevalent in front wheels of most cars and in high-end sports and racing cars.

Subcategories of independent suspensions include strut, multi-link, double wishbone, and swing arm.

3. Twist-Beam Rear Suspension

A simpler, cost-effective type where trailing arms from both wheels are connected by a crossbeam. It offers intermediate shock absorption between rigid and independent types and is commonly used in compact cars and front-wheel-drive vehicles.

Other Information on Suspensions

Influence of Suspension Performance

“Stiff” suspensions, characterized by rigid springs and high damper force, are preferred for racing cars where minimal body sway is desired. Conversely, “soft” suspensions with softer springs and lower damper force enhance ride comfort but may not be suitable for high-performance driving. The ideal suspension setup varies based on the vehicle’s purpose and required performance.

What Is an Automotive Spring?

An automotive spring is a crucial component of a vehicle’s suspension system, designed to enhance driving stability and ride comfort. Known also as coil springs, these components serve dual purposes:

• Improving driving stability by maintaining consistent contact with the road surface.
• Absorbing road surface impacts to enhance ride comfort.

The spring rate, or hardness, is adjusted based on the vehicle’s intended use, with corresponding adjustments to the shock absorber for optimal performance.

Uses of Automotive Springs

Automotive springs play a vital role in shock absorption and stability enhancement. The suspension design involves fine-tuning the spring’s softness and the damping force of shock absorbers to match the vehicle’s usage and operating environment.

While softer springs increase ride comfort by adapting more flexibly to road surfaces, they may reduce stability by increasing body roll during turns. Conversely, stiffer springs reduce body roll and enhance stability at the expense of ride comfort. Thus, the spring settings are often customized to balance between comfort and stability based on the vehicle’s purpose.

Principles of Automotive Springs

Automotive springs absorb shocks through contraction and expansion, mitigating impacts from the road. Special metals are used in their construction to endure repeated shocks without breaking or losing their shape. This functionality extends beyond suspensions to engine parts and clutches due to their durable and flexible nature.

Other Information on Automotive Springs

1. Suspension Structure

The suspension system includes:

• Shock Absorber (Damper): Dampens the coil spring’s motion to stabilize the vehicle body, enhancing stability and ride quality.
• Suspension Arm: Supports the tires and limits their position relative to the road surface, contributing to driving stability.

2. Suspension System Types

Suspension systems are categorized into axle suspension and independent suspension:

• Axle Suspension System: Connects the left and right wheels with an axle, offering simplicity, durability, and ease of maintenance but at the cost of ride comfort. Commonly used in economically priced vehicles.
• Independent Suspension System: Allows independent movement of each wheel, improving stability and comfort. Preferred in sports and luxury vehicles, though also found in the front suspension of lower-priced models due to higher production costs.

What Is a Steering Wheel?

A steering wheel, a key component of a vehicle’s steering mechanism, is a circular device that allows drivers to control the direction of the vehicle. It consists of a rim for gripping, a hub that connects to the steering shaft, and spokes that link the rim to the hub, facilitating the adjustment of the vehicle’s travel direction.

Uses of Steering Wheels

Steering wheels enable drivers to change the vehicle’s wheel angle, directly affecting the direction of travel. By gripping the steering wheel and rotating it, drivers can maneuver the vehicle to the right or left, with the rotation direction determining the movement. Larger steering wheels in trucks and buses reduce the torque needed for operation due to their size and the vehicle’s weight, while smaller steering wheels in racing and sports cars allow for quicker, more agile responses.

Principles of Steering Wheels

The steering wheel operates on the principle of leverage, where the rotation of the wheel—essentially a large circle—transmits movement to the smaller steering shaft in the center. This transmission of movement extends to the steering gearbox and then to the tie rods, which adjust the wheels’ direction, enabling steering with minimal effort.

Other Information on Steering Wheels

1. Ackermann Mechanism

This steering principle ensures that during a turn, the inner wheel rotates at a sharper angle than the outer wheel, reducing tire load and improving cornering efficiency. Unlike parallel steering mechanisms, where both wheels turn at the same angle, the Ackermann mechanism allows for a more natural and effective steering response.

2. Steering Mechanism Types

Rack and Pinion Type: Known for its simplicity, lightweight design, and high responsiveness, this system pairs a pinion gear with a rack bar and is commonly found in sports models.

Ball Nut Type: With a more complex design than the rack and pinion, this type offers smoother operation and is suited for larger vehicles needing more steering force.

Power Steering: To assist in steering without heavy manual effort, power steering systems use hydraulic or electric power, mitigating the force required to turn the steering wheel, especially in vehicles with heavy front ends or significant tire-ground friction.

What Is an Automotive Radiator?

An automotive radiator is a key component of a vehicle’s cooling system, designed to prevent the engine from overheating during extended periods of use or in high temperatures. It cools the engine by circulating coolant through the radiator core, where it is cooled by airflow before returning to the engine.

Uses of Automotive Radiators

The primary function of an automotive radiator is to dissipate heat from the engine, preventing overheating that can lead to engine seizure. By circulating coolant, the radiator absorbs and removes heat from the engine, ensuring it operates within a normal temperature range.

Principles of Automotive Radiators

Coolant flows through the radiator core, where it is cooled by driving wind and fan airflow. The core features fins or plates to increase the heat dissipation area, enhancing the efficiency of heat exchange with the air. This cooled coolant then circulates back to the engine to absorb more heat, repeating the cooling cycle.

Structure of Automotive Radiators

Automotive radiators consist of two header tanks connected by a core with numerous narrow passages, maximizing the surface area for heat exchange. Traditionally made from brass or copper, modern radiators often feature aluminum cores and plastic headers for reduced cost and weight, though this may impact durability and leak resistance.

Other Information on Automotive Radiators

1. Difference in Flow Type

Radiators can be categorized by coolant flow direction: vertical (downflow) or horizontal (crossflow). The choice between these types often depends on the vehicle’s design and origin.

2. Automotive Cooling System Components

The cooling system includes several key components:

• Water Jacket: A channel around the engine where coolant flows, absorbing heat from the combustion chamber and cylinder walls.
• Radiator Cap: Seals the system, maintaining pressure to increase the coolant’s boiling point, with valves to manage system pressure.
• Water Pump: Circulates coolant using engine power, with its speed correlating to engine speed.
• Thermostat: Controls coolant flow based on temperature, optimizing engine warm-up and cooling efficiency.
• Coolant: A mixture of water, ethylene glycol, and additives, designed to prevent corrosion, freezing, and improve cooling performance.

What Is a Seat Belt?

A seat belt is a safety device installed in vehicles to secure passengers during impact or sudden deceleration, thereby preventing injuries. Commonly known as safety belts, they mitigate the risk of passengers being thrown against the vehicle interior or ejected during a collision.

Modern seat belts often feature pretensioners and load limiters to initially tighten and subsequently ease the belt, minimizing pressure on the passenger’s chest. Adjustable belt anchors cater to different passenger heights, enhancing comfort and safety.

Applications of Seat Belts

Seat belts are integral to the safety systems of automobiles, boats, airplanes, roller coasters, and rockets. They protect passengers from injury during turbulence, collisions, or emergency stops by preventing them from being thrown against the interior or out of the vehicle.

The concept of seat belts dates back to 1899 following a fatal car accident in England. The first commercial use in passenger cars was in 1946, marking a significant milestone in automotive safety.

Principles of Seat Belts

The three-point seat belt, the most prevalent type, includes an emergency locking retractor (ELR) that locks during a collision. This mechanism consists of a sensor ball, a locking gear, and a claw (actuator). Upon impact, inertia moves the ball, triggering the gear and claw to lock the belt in place, securing the passenger.

Types of Seat Belts

Seat belts vary in design, including two-point, three-point, and full-harness configurations. The three-point seat belt, securing the body at both shoulders and hips, offers the most effective protection and is the standard in modern vehicles.

1. Two-Point Type

This variant secures the passenger at the waist but provides less protection in a crash compared to three-point seat belts.

2. Three-Point Type

The most common and effective type, providing over-the-shoulder and lap protection.

3. Full Harness Type

Offering the highest level of safety, full harness seat belts include multiple points of restraint, such as four-point, five-point, and six-point harnesses, suitable for high-risk environments.

Structure of Seat Belts

Seat belts consist of high-strength materials capable of withstanding forces up to 50 times a person’s weight. The system includes the belt webbing, retractor mechanism, anchorage points, and buckle.

1. Belt Assembly

Comprises the complete seat belt system, including retractor, anchors, webbing, and buckle.

2. Retractor

A device that rolls up excess belt webbing, keeping it taut yet allowing for movement.

3. Anchorage

The points where the seat belt is secured to the vehicle structure.

4. Buckle

The locking mechanism that secures the belt around the passenger.

5. Strap

Includes various types of straps for different body parts: lumbar (lap), shoulder, and leg straps.

What Is an Automotive Air Conditioner?

An automotive air conditioner is a system designed to control the temperature and humidity within a vehicle’s cabin. It operates by circulating a refrigerant through a closed system, effectively regulating the interior climate for comfort.

The system’s core component, the compressor, is powered by the vehicle’s engine. In electric vehicles, the heating function may utilize an electric heating element to warm water within the heater core, compensating for the absence of engine waste heat.

Uses of Automotive Air Conditioners

Automotive air conditioners maintain a comfortable cabin temperature and humidity level, similar to residential units. They play a crucial role in preventing window fogging, especially under high humidity conditions or with multiple passengers.

Activating the air conditioner alongside the heater can mitigate window fogging in winter by dehumidifying the cabin air.

Principles of Automotive Air Conditioners

The air conditioning system relies on a refrigerant, often referred to as air conditioning gas, for heat exchange processes. These processes include:

1. Compression

The compressor elevates the refrigerant’s pressure and temperature, transitioning it from a gas to a semi-liquid state.

2. Cooling

In the condenser, the semi-liquid refrigerant releases its heat, condensing into a high-pressure liquid.

3. Atomization

Through the expansion valve, the refrigerant is rapidly expanded, resulting in a low-temperature and low-pressure mist.

4. Heat Exchange

This mist moves to the evaporator, where it cools and dehumidifies the air being circulated into the cabin.

Other Information on Automotive Air Conditioners

1. Fuel-Efficient Use

Efficient operation of the automotive air conditioner can impact fuel consumption. Rapid cooling to the desired temperature is more fuel-efficient than prolonged, low-intensity use.

Minimizing sunlight exposure inside the cabin, which contributes to higher temperatures through infrared radiation, can also reduce the need for air conditioning.

2. Types of Air Conditioner Gas

The refrigerant R12, used historically, was phased out by 1995 due to its ozone-depleting properties. Today, HFC134a is common, although it is a potent greenhouse gas. R1234yf is emerging as a more environmentally friendly alternative, with lower global warming potential and no ozone depletion impact, signaling a shift towards more sustainable refrigerants in automotive air conditioning.

What Is a Disc Brake?

A disc brake is a type of braking system used in various vehicles, comprising three main components: the disc rotor, brake caliper, and brake pads. Located inside the wheel, this system is visible from the outside and is known for its high heat dissipation capability, which helps prevent brake fade and water fade.

Uses of Disc Brakes

Disc brakes are utilized in numerous applications where reliable deceleration and stopping of wheels are essential. Their use includes passenger cars, motorcycles, bicycles, trains, aircraft, construction machinery, and agricultural machinery. Recently, with advancements in electronically controlled braking systems (EBS), disc brakes have also found applications in commercial vehicles, traditionally dominated by drum brakes.

Principle of Disc Brakes

The working principle of disc brakes involves the conversion of kinetic energy into heat energy through friction. When the brake pedal is depressed, hydraulic pressure activates the piston in the brake caliper, pressing the brake pads against the disc rotor. The resulting friction slows down the wheel’s rotation, effectively stopping the vehicle.

Types of Disc Brakes

There are two primary types of disc brakes:

1. Floating Type Disc Brakes

These have pistons on one side of the brake caliper and are commonly used in passenger cars due to their simplicity, light weight, and cost-effectiveness.

2. Opposed Type Disc Brake

In this system, pistons are placed on both sides of the disc rotor, applying pressure evenly. Known for providing high levels of braking force, these are often found in sports cars and large, high-performance vehicles.

Other Information on Disc Brakes

1. Differences From Drum Brakes

Drum brakes work by pressing brake shoes against the inside of a rotating wheel, creating friction to slow down the wheel. While the principle of converting kinetic energy into thermal energy is similar, drum brakes have better constraining power due to a larger contact area and a self-servo effect. However, they have poorer heat dissipation compared to disc brakes, making them more prone to fade phenomena.

2. Life Span of Disc Brakes

The lifespan of disc brakes, particularly the brake pads and disc rotors, varies based on usage. Regular inspection is essential as brake pads typically last between 20,000 to 60,000 miles, and disc rotors around 60,000 miles. High-performance disc brakes may require more frequent maintenance due to increased load and wear.

What Is a Turbocharger?

A turbocharger is a type of supercharger used to enhance the performance of an engine. It increases the engine’s power output by compressing air and delivering it to the engine. This allows smaller engines, such as those in minicars, to produce power comparable to larger engines by increasing the amount of air intake.

Principle of Turbochargers

Turbochargers consist of three main components:

• Turbine: Rotates using the power of exhaust gases.
• Compressor: Compresses intake air.
• Housing: Channels the flow from the turbine and compressor.

Powered by exhaust gas, the turbine drives the compressor, which in turn compresses and supplies air to the engine’s cylinders.

Uses of Turbochargers

Turbochargers are effective at high engine speeds, leveraging the engine’s exhaust gases to boost power. They are more efficient than superchargers and can improve fuel efficiency. Turbochargers are widely used in various applications, including automobiles, ships, power generators, construction machinery, and aircrafts.

Types of Turbochargers

There are several types of turbochargers, each with a unique design.

• Single Turbocharger: Common in light cars and compact cars due to a simpler, lighter design.
• Twin Turbochargers: Utilizes two different types of turbochargers, optimizing performance at low RPM. However, they are heavier and more expensive.
• Twin-Scroll Turbochargers: Features a single turbine with two exhaust gas intake ports, reducing turbo lag and enhancing efficiency across all RPM ranges.

Other Information on Turbochargers

• Electric Turbochargers: Uses an electric motor to assist operation at low rpm ranges. While more efficient, they are heavier, more expensive, and face design challenges due to exhaust gas temperatures.
• Downsizing Turbo: A strategy to reduce the size and weight of the engine while maintaining output using a turbocharger.
• Difference From Superchargers: Turbochargers use engine exhaust gases for power, while superchargers are powered directly by the engine’s crank and belt. Turbochargers can be more efficient overall, but may experience turbo lag at lower engine speeds.

What Is a Car Brake?

Car brake is a device used to slow down or stop an automobile. Car brakes, also known as foot brakes, are activated by depressing the pedal with the foot. They are distinguished into two main types: disc brakes and drum brakes.

Either of these two types, or a combination of both, is used in car braking systems. Disc brakes, once exclusive to luxury cars, are now more common in various vehicles.

Uses of Car Brakes

Car brakes are essential for slowing or stopping a vehicle. They are activated when the driver steps on the foot brake.

Activating the car brake is straightforward, requiring the driver to press the foot brake. However, sudden application can result in emergency braking, which should be done with caution.

To slow down and stop smoothly, gently press the brake with your toes without engaging the heel initially. As the vehicle slows, slightly ease off before coming to a stop, and then firmly apply the brake. This technique allows for smooth deceleration and stopping.

Principles of Car Brakes

Depressing the foot pedal applies pressure to the brake fluid in the car’s brake system. This hydraulic pressure activates the brake at the tire section.

1. Disc Brakes

Disc brakes convert the kinetic energy of the vehicle into thermal energy using disc rotors and brake pads. The brake pads clamp onto the disc rotor, which rotates with the wheels, creating friction that slows and stops the vehicle. Modern disc rotors often feature ventilation channels for efficient heat dissipation, especially useful at high speeds or during prolonged braking.

2. Drum Brakes

Drum brakes use a drum and brake shoes to decelerate and stop the vehicle. When applied, the brake shoes expand against the rotating drum, converting kinetic energy into thermal energy through friction. Though less powerful than disc brakes, drum brakes are cost-effective and still used in some models.

Other Information on Car Brakes

1. Hand Brake

Also known as hand brakes, these are used to secure a vehicle while parked. They operate a brake drum or disc connected to the rear wheels via a cable. Modern vehicles sometimes use electronically controlled hand brakes, which offer smoother operation and additional safety and comfort features.

2. Automatic Braking System

The automatic emergency braking system (AEB) helps prevent accidents by automatically applying the brakes when a potential collision is detected. Using radar, cameras, and ultrasonic sensors, AEB assesses the risk of collision and either warns the driver or applies the brakes automatically. While AEB enhances safety, it is supplementary and requires driver vigilance.