What do pulleys do in a car




















Well that might not be an issue as it takes only small amount of energy to work two or three small pulleys, but it becomes an issue when you are trying to squeeze every last drop of performance out of your engine. To make use of every drop of engine performance, many experts suggest installing special pulleys that take less energy to work and are still capable to run your accessories. There are different types of pulleys that come in different sizes, which you can choose depending on your need.

Block and tackle hoist: this pulley system is often seen in shipping because it contains multiple pulleys in blocks to gain mechanical advantage in lifting the material.

By doubling up the length of the line to pull the load, then it reduces the input force required. Fixed and movable pulleys: These types of pulleys are very simple. Fixed pulleys are type which can not be moved when the load moves and are therefore serve to change the direction of the input force. Serpentine pulley system: this type of pulley system is connected to several pulleys with a single belt.

This can be used in machines that connect with different accessories in a single machine. Camshafts are typically connected to crankshafts by sprocket-driven chains or belts, so accessories that are powered by a cam pulley are indirectly driven by the crankshaft as well. The most common car pulleys are used to power accessory devices. When an accessory pulley is rotated by the motion of a drive belt, it causes a device to activate.

The pulley on a power steering pump causes fluid to pressurize and circulate through the system, and one on an alternator results in the formation of a magnetic field which can be converted into usable electricity.

Most of these pulleys activate the corresponding accessories whenever the engine is running, though there are a few exceptions. AC compressors commonly have clutch mechanisms built in, which can allow a pulley to spin freely when the air conditioning is not turned on. Car pulleys that do not provide power or operate accessories are typically referred to as tensioners and idlers. Those are some of the advantages, but let's face it-even though the big three have adopted the serpentine system for most current production vehicles, V-belts are still around and they work just fine.

The decision ultimately comes down to the cost of the conversion and the kind of look you're trying to achieve. Calculating Pulley RPM Calculating a pulley's rpm can be very handy when it comes to optimizing an accessory system or sorting out problems. If you don't already know the overall diameter of each pulley, place a tape measure from one lip of the pulley to the other to find out.

The crank pulley is used as the driver pulley since it's the source of rotation , and the water pump, alternator, and power steering pump are called the driven pulleys. Once you have the measurements, simply plug them into the following equation for the rotating rpm. If you change the diameter of any of the pulleys, you can easily calculate the new rotating rpm along with the percentage of change. For example, let's plug in the numbers for a typical application with a small-block Underdrive Pulleys The biggest drawback to belt-driven accessory systems is that it takes precious horsepower to turn them.

One method of regaining some of the power lost to the parasitic drag effect is to underdrive the system.

Underdrive is generally achieved by swapping a smaller crank pulley in conjunction with slightly larger water-pump and alternator pulleys. By slowing the rotating rpm of the alternator, charging output can be reduced enough to cause the headlights to dim at idle and prevent the battery from properly charging.

In the process, we've reduced the speed of the other accessories relative to the crankshaft speed, reduced parasitic drag, and gained a few extra ponies.

And to think we used to hate math in grade school.



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