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Threshold Braking
Threshold braking or limit braking is a driving technique most commonly used in motor racing, and in road vehicles to slow a vehicle at the maximum rate using the brakes. The technique involves the driver controlling the brake pedal (or lever) pressure to maximize the braking force developed by the tires. The optimal amount of braking force is applied at the point when the wheel just begins to slip. Friction Braking beyond the slipping point causes the tire to slide and reduces the frictional adhesion between the tire and driving surface. The aim of threshold braking is to keep the amount of tire slip at the optimal amount, the value that produces the maximum frictional, and thus braking, force. When wheels are slipping significantly (kinetic friction), the amount of friction available for braking is typically substantially less than when the wheels are not slipping (static friction), thereby reducing the braking force and eliminating steering ability. Peak friction occurs between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Driving
Driving is the controlled operation and movement of a land vehicle, including cars, motorcycles, trucks, and buses. A driver's permission to drive on public highways is granted based on a set of conditions being met, and drivers are required to follow the established Traffic code, road and traffic laws in the location they are driving. The word "driving" has etymology dating back to the 15th century. Its meaning has changed from primarily driving working animals in the 15th century to automobiles in the 1800s. Driving skills have also developed since the 15th century, with physical, mental and safety skills being required to drive. This evolution of the skills required to drive have been accompanied by the introduction of driving laws which relate not only to the driver but also to the driveability of a car. The term "driver" originated in the 15th century, referring to the occupation of driving working animals such as pack or draft horses. It later applied to electric railway d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tire
A tire (North American English) or tyre (Commonwealth English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineering), traction on the surface over which the wheel travels. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, providing a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, called a contact patch, designed to match the vehicle's weight and the bearing on the surface that it rolls over by exerting a pressure that will avoid deforming the surface. The materials of modern pneumatic tires are synthetic rubber, natural rubber, fabric, and wire, along with carbon black and other chemical compounds. They consist of a tire tread, tread and a body. The tread provides Traction (engineering), traction while the body provides containment for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slip (vehicle Dynamics)
In (automotive) vehicle dynamics, slip describes the relative motion between a tire and the road surface it is moving on. This slip can be generated either by the tire's angular velocity being greater or less than the free-rolling speed (referred to as slip ratio), or by the tire A tire (North American English) or tyre (Commonwealth English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineeri ...'s front facing direction being at an angle to its direction of motion (referred to as slip angle). When both of these measurements do not equal zero, the tire enters a state called combined slip. Longitudinal slip ratio The longitudinal slip (commonly referred to as longitudinal slip ratio) is used to describe the rotational state of a tire at any given speed. The most common definition is given as the ratio between the tire's slip velocity and the forwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetic Friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of the processes involved is called tribology, and has a history of more than 2000 years. Friction can have dramatic consequences, as illustrated by the use of friction created by rubbing pieces of wood together to start a fire. Another important consequence of many types of friction can be wear, which may lead to performance degradation or damage to components. It is known that frictional energy losses account for about 20% of the total energy expenditure of the world. As briefly discussed later, there are many different contributors to the retarding force in friction, ranging from asperity deformation to the generation of charges and changes in local structure. When two bodies in contact move relative to each other, due to these various ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-lock Braking System
An anti-lock braking system (ABS) is a Automotive safety, safety anti-Skid (automobile), skid Brake, braking system used on aircraft and on land motor vehicle, vehicles, such as cars, motorcycles, trucks, and buses. ABS operates by preventing the wheels from locking up during braking, thereby maintaining Traction (mechanics), tractive contact with the road surface and allowing the driver to maintain more control over the vehicle. ABS is an automated system that uses the principles of threshold braking and cadence braking, techniques which were once practiced by skillful drivers before ABS was widespread. ABS operates at a much faster rate and more effectively than most drivers could manage. Although ABS generally offers improved vehicle control and decreases stopping distances on dry and some slippery surfaces, on loose gravel or snow-covered surfaces ABS may significantly increase braking distance, while still improving steering control. Since ABS was introduced in production v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadence Braking
Cadence braking or stutter braking is a driving technique that involves pumping the brake pedal and is used to allow a car to both steer and brake on a slippery surface. It is used to effect an emergency stop where traction is limited to reduce the effect of skidding from road wheels locking up under braking. This can be a particular problem when different tires have different traction, such as on patchy ice for example. Its use in an emergency requires a presence of mind that the situation itself might preclude. Cadence braking is supposed to maximize the time for the driver to steer around the obstacle ahead, as it allows the driver to steer while slowing. It needs to be learned and practiced. For most drivers of modern cars, it has been entirely superseded by ABS, however it is still a valuable skill for drivers of non-ABS equipped vehicles such as classic cars. Maximum braking force is obtained when there is approximately 10–20% slippage between the braked wheel's rotationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circle Of Forces
The circle of forces, traction circle, friction circle, or friction ellipse is a useful way to think about the dynamic interaction between a vehicle's tire and the road surface. The diagram below shows the tire from above, so that the road surface lies in the ''xy''- plane. The vehicle to which the tire is attached is moving in the positive ''y'' direction. In this example, the vehicle would be cornering to the right (i.e. the positive ''x'' direction points to the center of the corner). Note that the plane of rotation of the tire is at an angle to the actual direction that the tire is moving (the positive ''y'' direction). Put differently, rather than being allowed to simply "roll" in the direction that it is "pointing" (in this case, rightwards from the positive ''y'' direction), the tire instead must "slip" in a different direction from that which it is pointing in order to maintain its "forward" motion in the positive ''y'' direction. This difference between the direction the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Driving Techniques
Driving is the controlled operation and movement of a land vehicle, including cars, motorcycles, trucks, and buses. A driver's permission to drive on public highways is granted based on a set of conditions being met, and drivers are required to follow the established road and traffic laws in the location they are driving. The word "driving" has etymology dating back to the 15th century. Its meaning has changed from primarily driving working animals in the 15th century to automobiles in the 1800s. Driving skills have also developed since the 15th century, with physical, mental and safety skills being required to drive. This evolution of the skills required to drive have been accompanied by the introduction of driving laws which relate not only to the driver but also to the driveability of a car. The term "driver" originated in the 15th century, referring to the occupation of driving working animals such as pack or draft horses. It later applied to electric railway drivers in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
