Changing Trends in Brake Efficiency
Career Path : Automotive
Few automobile parts are more taken for granted than the braking system â drivers expect their brakes to always work effectively and consistently. When it comes to car safety, braking systems are the most critical to maintain. Most commonly, brakes use friction to convert kinetic energy to heat but due to varying temperature, humidity, wear and age, this friction is not constant. Brake pad designers strive to develop more stable pad compounds that will maintain consistency over a wide range of operating conditions while reducing brake noise, vibration and harshness. Braking systems have rapidly advanced in recent years, with ceramic friction technology and regenerative braking among the most popular trends.
Those are the Brakes
For many years it was industry norm to use asbestos in brake pads and linings, among other car parts. As friction wore down brake linings, asbestos dust would be released and trapped in brake housing, which would create health risk to workers when the housing was opened. When asbestos was phased out because of its cancerous properties in the â70s and â80s, it was initially replaced by semi-metallic compounds. Most vehicles on the road today have durable and cost-effective metallic brake pads, which provide dependable performance but reduce fuel economy because of their heaviness.
A growing number of automakers have recognized ceramic friction brake pads to be optimal for smooth, quiet braking under a variety of conditions. They are now the fastest growing segment in the aftermarket pad category and are used in an estimated 40% of new vehicle models sold in North America. Ceramic brake pads require much less pedal exertion to ensure a smooth stop and cause less wear on brake rotors than metal. They are more expensive than the alternative but since dust is almost eliminated regarding bonding to wheels, they can save money in long-term maintenance from a professional with auto technician training.
A physicist would surely consider the waste of energy every time you step on the brakes. When a car slows, the kinetic energy that propelled it forward has to go somewhere â useless heat and sometimes acoustic energy, i.e. squealing. The beauty of regenerative braking is that the energy dissipated in slowing is recaptured and converted into electricity, which can then recharge a hybrid carâs battery. With electric or hybrid vehicles, braking puts the electric motor into reverse mode, causing it to run backwards and slow the wheels. Hybrids also have friction brakes as a back-up system to ensure thereâs enough stopping power. There has been a general trend towards âbrake-by-wireâ systems in which traditional mechanical functions will be performed electronically. A brake controller, an electronic remote control, operates similar to anti-lock braking systems to monitor wheel speed and calculate how much rotational force is available, then ensures optimal power is received by the batteries while deciding whether the friction brakes will be necessary to stop the car. Contemporary auto mechanic courses must increasingly focus on the effect these technologies are having on vehicle maintenance.
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