In an automotive engine, a drive belt is used to drive various engine components. These components might include a power steering pump, alternator, water pump, air conditioning compressor, etc. The belt is often placed on an idler pulley, which serves as a guide or a belt tensioner. This is either spring-loaded, hydraulic, or manual.
In this reading, we’ll explore what a drive belt is, its function, diagram, types, and how it works. We’ll also learn its advantages and disadvantages.
Let’s get started!
What Is A Drive Belt?
A drive belt is a single, continuous belt used in automotive engines to rotate multiple peripheral devices in the engine. The belt is allowed to pass over more than three pulleys, which are designed to fitly enclose the belt to avoid slipping.
Idler pulleys are pressed against the back of the belt, forcing it into the shape of the pulley. A drive belt can last at least more than 10,000 miles. Note: This mileage may vary; quality drive belts, especially serpentine belts, can last much longer, often over 60,000 miles.
In rear-wheel-drive vehicles or cars with boxer engines, it’s visible from the front. In some rear-wheel cars and older cars, the drive belt also drives the front engine fan. Some engine designs use two of them, depending on the configuration and the device layout.
Functions Of A Drive Belt
A drive belt is a crucial component in many mechanical systems, particularly in automobiles and machinery. Here are its primary functions:
The primary purpose of a drive belt is to drive or power the engine accessories.
Drive belts use one source of energy to power multiple components.
It increases the mechanical efficiency of the engine.
A drive belt powers the engine water pump, so if it breaks, it will stop running and lead to overheating.
In addition, the belt drives the hydraulic power steering. So, the steering assist will be lost as the power steering pump is disabled from the drive.
The alternator that also supplies electrical power will stop working as the device is disabled.
An attached pulley to the engine crankshaft drives the belt. Most vehicles are designed to use one or two drive belts, but it’s called a serpentine belt when an engine has one drive belt.
There are several types of drive belts, each designed for specific applications and performance requirements. Here are the most common types:
Serpentine Belt
A serpentine belt runs between pulleys and accessories under a car’s hood. Most cars made after 1990 use this kind of drive belt. Additionally, it is easy to install and remove, has a longer lifespan than other drive belts, and transfers power from the engine to the compressor, water pump, alternator, and steering pump of an automobile.
V-Belts
In most engines, a V-belt connects a couple of accessories and runs on a crank and pulley system. Many older vehicles use several V-belts for power steering, air conditioning, and other crucial systems.
Compared to serpentine belts, V-belts can be more challenging to replace. Furthermore, loose V-belts may result in alternator failure and engine overheating.
Timing Belts
A timing belt connects the crankshaft and camshaft of your car’s engine; the crankshaft rotates the engine’s pistons, while the camshaft opens and closes ignition valves. Most of the time, the timing belt is hidden under a timing cover, making it hard to see.
However, it is important to pay attention to the timing belt because if it wears out and malfunctions, it could lead to an expensive and time-consuming engine repair. It can work for at least 60,000 to 90,000 miles before replacement.
Well, some engines are designed with timing chains instead of belts so they can last throughout the engine’s lifespan. Instead of drive belts that crack or break over time.
How A Drive Belt Works
A drive belt drives the AC compressor, power steering pump, water pump, and alternator. There is a pulley in each of these parts that the driving belt goes over. The crankshaft has a pulley with a drive belt, but it doesn’t use the belt for power.
The crankshaft pulley rotates when the engine is running, enabling the drive belt to rotate every other pulley to which it is attached.
The belt works with the idler, tensioner, and pulleys to keep the devices connected to the drive belt. The engine might not run at all if any of the above parts are broken. The drive belt keeps working as long as the engine is running until the car is turned off.
The main source of energy comes from the combustion process, which also provides power to turn the crankshaft.
What is the Difference Between a Drive Belt and a Timing Belt?
The timing belt ensures that the engine’s crankshaft, pistons, and valves operate in sync or on time. Accessory drive belts are used to drive all accessories that run off the front of the engine.
The drive belt and timing belt are made of the same material, which they use to drive different components in internal combustion engines. Their designs are quite different since their positions in the engine are not the same. The 2-belt works with a tensioner, giving it enough strength to drive the components.
A drive belt is also known as a serpentine belt or alternator belt. It is a rubber belt that powers engine accessories and performs critical functions. It is crucial for the engine’s functioning and can break down if it fails.
Modern engines often use multiple drive belts to drive multiple components, making it more complex to change. The timing belt on the other hand, connects the camshaft and crankshaft in internal combustion engines, synchronizing the timings of valves and pistons.
This ensures perfect compression and combustion cycles, allowing air and fuel to enter the combustion chamber at the right time and exhaust gas to escape.
The rotation of the timing belt controls the opening and closing of intake and exhaust valves, allowing air and fuel to enter the combustion chamber and exhaust gas to escape.
This control also controls the reciprocating movement of the piston, which turns the crankshaft that powers the camshaft. The table below shows the difference between the two engine components.
S/N
Drive Belt
Timing Belt
1.
The drive components of the vehicle (alternator, fan, etc.)
Two essential components that cause the engine to work are the camshaft and crankshaft.
2.
All components begin work immediately after the engine starts running.
The two components are synchronized
3.
It can be complex when multiple belts are used to power the components.
Its working is less complex as it uses one drive belt to drive the components
4.
Drive belts are less expensive.
Timing belts are expensive.
5.
The damage to the drive belt will cause the device’s power to stop working
Damage to the timing belt will cause a breakdown of the vehicle.
6.
Modern engines are designed to use multiple belts to power different components.
Timing belts use just a single belt to drive the components.
7.
Drive belts are mounted on the tensioner pulley to avoid slipping.
Timing belts are attached to components that carry sprockets on them. This ensures the synchronization of the systems.
8.
A broken drive belt may cause a complete breakdown of the engine.
While a broken timing belt will stop the engine from working, no component in the engine is damaged.
Advantages
Common advantages of a drive belt include:
Drive belts use less space and are more effective than the older multiple-drive belt system.
The belt is able to undergo an increase in tension without stretching.
Since higher tension reduces slip, belt life and mechanical efficiency are increased.
The belt is much easier to maintain and replace since there is no need for multiple belts to be removed.
Since only one tensioner belt is needed for all the peripheral components, they can simply be mounted on the engine without the need to swivel.
Less slip allows a drive belt to work well on lower-ratio pulleys as the engine load is reduced.
Fuel economy and available power have increased.
The tendency to flip over in the pulley groove is eliminated.
Disadvantages
Despite the great advantages of drive belts, some limitations still exist. Here are its major disadvantages:
The vehicle instantly loses multiple critical functions as soon as the belt breaks or is knocked loose.
The vehicle becomes unusable in no time as the engine cooling is terminated.
Lack of redundancy.
Breakage of the single belt means loss of all accessories.
