Suspension | How it Works

Summary

This humorous and engaging video dives into the basics of vehicle suspension systems, comparing various types of suspensions, including leaf springs, torsion bars, and MacPherson struts. The host playfully explains the role of suspension in providing stability, comfort, and control while driving. With a mix of pop culture references, jokes, and science, the video breaks down complex engineering concepts into entertaining and digestible content. Viewers also get a quick look at front and rear suspensions, making this an educational yet light-hearted exploration of automotive dynamics.

Takeaways

• 🎵 The script begins with a reference to the song 'Bounce With Me' by Lil Bow Wow, highlighting the word 'bounce' in different contexts.
• 🔍 The term 'suspension' is humorously introduced with a variety of meanings, including workplace suspensions and suspension of disbelief.
• 🚗 The script discusses the importance of vehicle suspensions, explaining their role in maximizing tire-road friction, providing steering stability, and ensuring passenger comfort.
• 🛠️ It explains the basic function of a car suspension in absorbing and dissipating energy from road imperfections to prevent wheel loss of contact with the road.
• 🔄 Newton's Laws of Motion are used to describe how suspensions handle forces and acceleration caused by road bumps.
• 🔧 The script outlines the three fundamental components of any suspension system: springs, dampers, and anti-sway bars.
• 🌐 Different types of springs used in suspensions are mentioned, such as leaf springs, torsion bars, and coil springs, each with their specific applications and characteristics.
• 💡 The concept of sprung and unsprung mass is introduced, explaining how spring stiffness affects a car's response to driving conditions.
• 🚦 Dampers, specifically shock absorbers, are described as crucial for slowing down and reducing vibratory motion, converting kinetic energy into heat.
• 🔧 Struts are introduced as a combination of shock absorbers and springs, providing both dampening and structural support for the vehicle's suspension.
• 🔄 The script covers various types of front and rear suspensions, including MacPherson struts, double wishbone, and dependent rear suspensions, detailing their functions and benefits.

Q & A

What is the main theme of the song 'Bounce With Me' by Lil' Bow Wow?

The main theme of the song 'Bounce With Me' by Lil' Bow Wow is about having a good time and dancing energetically with someone.

Why is the concept of 'bouncing' considered bad in the context of suspensions?

In the context of suspensions, 'bouncing' is considered bad because it refers to the uncontrolled movement of a vehicle's wheels, which can lead to a loss of traction and stability, affecting the driver's control.

What are the three main functions of a car's suspension system?

The three main functions of a car's suspension system are to maximize friction between the tires and road surface for better control, provide steering stability with good handling, and ensure the comfort of passengers.

According to the script, what are the two perspectives from which auto engineers approach suspension design?

Auto engineers approach suspension design from two perspectives: ride, which is the car's ability to smooth out a bumpy road, and handling, which is the car's ability to safely accelerate, brake, and corner.

What is Newton's Law of Motion and how does it relate to vehicle suspension?

Newton's Law of Motion states that forces have both magnitude and direction. In the context of vehicle suspension, a bump in the road causes the wheel to move up and down, perpendicular to the road surface, which is the direction. The magnitude of the force depends on the size of the bump, affecting the wheel's vertical acceleration.

What is the purpose of springs in a vehicle's suspension system?

The purpose of springs in a vehicle's suspension system is to absorb the energy from the vertically accelerated wheel when it hits a bump, allowing the frame and body to ride undisturbed while the wheels follow the road's bumps.

What are the three fundamental components of any suspension system?

The three fundamental components of any suspension system are springs, dampers (such as shock absorbers), and anti-sway bars.

Why are dampers necessary in a vehicle's suspension system even though springs absorb energy?

Dampers are necessary in a vehicle's suspension system because, while springs absorb energy, they are not efficient at dissipating it. Dampers, such as shock absorbers, slow down and reduce the vibratory motion by converting the kinetic energy of suspension movement into heat energy that can be dissipated.

What is the difference between a dependent and an independent suspension system?

A dependent suspension system, such as one with a rigid axle, binds the wheels together, while an independent suspension system allows each wheel to move independently, providing better handling and control.

What is the MacPherson strut and how does it contribute to a vehicle's suspension?

The MacPherson strut is a type of suspension system that consists of a single control arm and a strut assembly, allowing the tire and wheel to move upward and downward. It reduces the number of parts, lowers unsprung mass, and provides smooth driving comfort, making it common in front suspensions of front-wheel drive vehicles.

What is the purpose of anti-sway bars in a vehicle's suspension system?

Anti-sway bars, also known as stabilizer bars, are used in conjunction with shock absorbers or struts to provide additional stability to a moving vehicle. They help to minimize body roll and sway, contributing to a more consistent steering feel and better handling.

Outlines

00:00

🎵 The Bounce of Music and Mechanics

The paragraph humorously introduces the concept of 'bouncing' through the lyrics of Lil Bow Wow's song 'Bounce With Me' and transitions into discussing various types of suspension, both figurative and literal. It touches on workplace suspensions, suspension of disbelief, and vehicle suspension systems. The speaker acknowledges the vast variety of vehicle suspension types and sets the stage for a deeper dive into the basics of car suspensions. The historical context of car development is briefly mentioned, highlighting the importance of suspension in maximizing tire-road friction, ensuring steering stability, and passenger comfort. The paragraph ends with a playful nod to the audience, acknowledging the complexity of the topic and the speaker's intention to cover only the basics.

05:01

🔧 The Fundamentals of Vehicle Suspension

This paragraph delves into the science behind vehicle suspension, explaining the role of springs, dampers, and anti-sway bars. It discusses different types of springs used in vehicles, including leaf springs, torsion bars, and coil springs, and their applications in various car types. The importance of sprung and unsprung mass in vehicle dynamics is highlighted, along with the effects of spring stiffness on a car's response to road conditions. The paragraph further explains the function of dampers, focusing on shock absorbers and their role in converting kinetic energy into heat. The inner workings of twin-tube shock absorbers are described, including the compression and extension cycles. The discussion also covers struts, their dual function in dampening and supporting vehicle weight, and the MacPherson strut as a common example. The benefits of double wishbone suspension in controlling camber angle and minimizing roll and sway are also mentioned.

10:01

🚗 A Closer Look at Suspension Systems

The final paragraph continues the exploration of suspension systems, focusing on rear suspension configurations. It contrasts dependent and independent rear suspensions, describing the simplicity of leaf spring-based designs and the adaptability of coil spring setups. The paragraph emphasizes the versatility of suspension types, noting that any front suspension can be adapted for the rear. It also touches on the simplification of rear independent suspensions due to the absence of steering components. The commercial segment promotes Bombfell, a styling service for men, with a personal anecdote from the speaker about his experience with the service. The paragraph concludes with a call to action for viewers to subscribe to the channel and follow on social media, and a playful hint at an episode of another show where the speaker 'cut the springs on a car'.

Keywords

💡Suspension

Suspension refers to the system of components that connects a vehicle to its wheels while allowing movement and providing a smooth ride. In the video, it is the central theme, with various types of suspensions discussed, such as vehicle suspensions, suspensions from work, and the suspension of disbelief. The script uses humor to explain the importance of vehicle suspensions in maximizing tire-road friction and ensuring passenger comfort.

💡Bounce

Bounce is a term used in the script to describe the up-and-down movement of a vehicle's wheels and body caused by road imperfections. It is mentioned in the context of a song and then humorously contrasted with the negative connotation of 'bouncing' in other contexts, such as suspensions from work. The script emphasizes the need for a suspension system to absorb energy and prevent bounce for better vehicle control and comfort.

💡Vehicle Dynamics

Vehicle dynamics is the study of the forces at work on a moving vehicle, including how it handles acceleration, braking, and cornering. The script explains that a suspension system is a critical part of vehicle dynamics, as it absorbs the energy from wheel movement, allowing the vehicle to maintain contact with the road and providing stability.

💡Springs

Springs are components of a vehicle's suspension system that store and release energy to absorb impacts from the road. The script mentions different types of springs, such as leaf springs, torsion bars, and coil springs, each serving to support the vehicle's weight and dampen bumps in various ways.

💡Dampers

Dampers, such as shock absorbers, are crucial in a vehicle's suspension system to dissipate the energy absorbed by springs and control the speed of the spring's movement. The script describes how dampers work in conjunction with springs to prevent excessive bounce and ensure a smooth ride.

💡Anti-Sway Bars

Anti-sway bars, also known as sway bars or stabilizer bars, are components that connect opposite wheels and resist body roll during cornering. The script humorously refers to them as 'bars that hate Sway' before explaining their actual function in providing stability and preventing body roll.

💡MacPherson Strut

The MacPherson strut is a type of automotive suspension component that combines a shock absorber and a coil spring into a single unit. The script mentions it as a common and space-efficient design, especially for front suspensions in front-wheel-drive vehicles.

💡Double Wishbone Suspension

Double wishbone suspension, also known as A-arm suspension, is a type of independent suspension system that uses two wishbone-shaped arms to balance the wheel. The script explains how this design allows for more control over the wheel's camber angle and helps to minimize roll and sway, providing a consistent steering feel.

💡Rear Suspension

Rear suspension refers to the components at the back of a vehicle that connect the wheels to the vehicle body. The script discusses different types of rear suspensions, including dependent and independent systems, and how they can be simpler or more complex depending on whether they are integrated with the steering system.

💡Unsprung Mass

Unsprung mass is the mass of a vehicle's components that are not supported by the springs, such as the wheels and brake assemblies. The script mentions unsprung mass in the context of suspension design, where reducing it can lead to improved handling and ride comfort.

Highlights

The song 'Bounce With Me' by Lil' Bow Wow is used to introduce the concept of 'bouncing', which is humorously contrasted with the negative concept of 'suspensions'.

The variety of suspension types is likened to the vastness of options, with a playful dismissal of exact numbers to avoid 'nerdiness'.

Different types of 'suspensions' are outlined, including work suspensions, suspension of disbelief, and vehicle suspension systems.

A personal anecdote humorously connects the variety of DNA strands found in the narrator's bedroom to the types of vehicle suspensions.

The importance of car suspension in maximizing tire-road friction, providing steering stability, and ensuring passenger comfort is explained.

The role of Newton's Law of Motion in understanding how a car suspension responds to road imperfections is discussed.

The concept of vehicle dynamics, including ride, handling, road isolation, cornering, and road holding, is introduced.

The challenges of vehicle motion, such as dive and squat, and their impact on suspension design are highlighted.

The three fundamental components of any suspension system—springs, dampers, and anti-sway bars—are identified.

The function of anti-sway bars in providing stability alongside shock absorbers or struts is explained.

Various types of springs used in suspensions, including leaf springs, torsion bars, and coil springs, are described.

The distinction between sprung and unsprung mass in a vehicle's suspension and their impact on vehicle dynamics is clarified.

The role of dampers, specifically shock absorbers, in dissipating energy and controlling motion is detailed.

The inner workings of a twin tube shock absorber, including its pressure and reserve tubes, are explained.

The importance of velocity-sensitive shock absorbers in adjusting to road conditions and controlling unwanted vehicle motion is emphasized.

Struts are introduced as a combination of shock absorbers and coil springs, providing both dampening and structural support.

The MacPherson strut is highlighted as a significant innovation in strut design, contributing to reduced complexity and cost.

Double wishbone or A-arm suspension is described as a common front suspension type that allows for more control over wheel camber angle.

Rear suspensions are discussed, including dependent and independent systems, and their configurations based on leaf or coil springs.

The video concludes with a sponsored segment for Bombfell, an online clothing service for men, and a call to action for viewers to subscribe to Donut Media's channel.

Transcripts

(hip-hop music)

- "All I wanna do is see ya bounce with me, bounce with me."

Those are the words of young Lil Bow Wow

from the song "Bounce With Me"

("Bounce With Me" by Lil' Bow Wow)

The concept of bouncing is great in this classic song.

You know where bounce is bad?

Suspensions!

(electronic music)

There's billions of types of suspension, not literally,

but I'm not gonna go look up the exact number

like some kind of a nerd so maybe not billions,

but there's a lot of different types of suspension.

There's suspensions like when you're suspended from work

for biting the camera man,

there's suspensions like the suspension of disbelief

which allows you to believe in make believe stuff

like Superman can fly or life's gonna work out,

and there's the suspension system on your vehicle,

and those vehicle suspensions

have a huge variety of types as well.

There's more types of vehicle suspensions

than the types of DNA strands that were found in my bedroom

nine years ago on that fateful night in September.

(crowd gasps) That number was three.

We got a knife.

With such a wide variety of types,

we're barely gonna scratch the surface here

and touch on the basics in a few of the most common types.

So all of you in the comments

saying I forgot about this thing or that thing,

nah, I didn't, I know all about it,

In fact, I just left it out to tick you off.

(crowd booing) So get off my back, David.

Alright, when they invented the car it was awesome,

they're all smoking cigars

and patting each other on the back, eating some cold cuts

and congratulating each others like,

"This will revolutionize travel.

"The piston engine will get us places so fast."

"I love cold cuts."

But then, record scratch, (record scratches)

they realized all the power generated by an engine's useless

if the driver can't control the car.

(engine revving)

And almost as soon as the four stroke

internal combustion engine was mastered,

engineers went to work on perfecting the suspension.

Horse drawn carriages had suspensions,

but they only went so fast.

You hit those same bumps in the road at a greater speed,

it's gonna get a lot bouncier.

- Ow!

- The job of a car suspension is to one,

maximize the friction between the tires and road surface

during acceleration, cruising, and braking,

and two, provide steering stability with good handling,

and three, ensure the comfort of the passengers.

If all roads were perfectly flat

with no irregularities or bumps or waves or anything,

suspension wouldn't be as necessary,

but unlike me, even fresh laid pavement

has some imperfections.

Now, let's get science-y up in this garage.

Newton's Law of Motion says forces have both

magnitude and direction.

A bump in the road causes the wheel to move up and down,

perpendicular to the road surface, direction.

The magnitude depends on whether the wheel

is striking a giant bump or a tiny speck.

The wheel experiences a vertical acceleration

as it passes over an imperfection,

and that means the wheel goes up.

Without an intervening structure,

the vehicle's vertical energy

is transferred to the car's frame,

which moves the same direction, up.

The wheels can lose contact with the road completely

and then, 'cause of gravity,

the wheels would slam back down into the road surface,

and that is bounce, brother.

And if there was no gravity,

that bump could send you hurdling into space

until you go out into hyper space and see the event horizon.

Spooky.

You need a system that absorbs the energy

of the vertically accelerated wheel,

allowing the frame and body to ride undisturbed

while the wheels follow bumps in the road,

and that's all part of vehicle dynamics,

the study of forces at work on a moving car.

Auto engineers come at this from two perspectives, ride,

(engine revving) a car's ability to smooth out

a bumpy road and handling, oop,

and handling, a car's ability to safely accelerate,

brake, and corner

and those break down into these principles,

road isolation, the vehicle's ability to absorb

or isolate road shock from the passenger compartment,

cornering, the ability of a vehicle to travel a curved path,

and road holding, the degree to which a car maintains

contact with the road surface

in various types of directional changes

and in a straight line.

For example, the weight of a car will shift

from the rear tires to the front tires during braking

because the nose of the car dips toward the road.

This type of motion is known as dive.

The opposite effect, squat, occurs during acceleration,

which shifts the weight of the car

from the front tires to the back.

These are the challenges

that the suspension system has to handle.

Like I said earlier,

there's a buttload of suspension varieties

and a car can, and usually does,

have a different type of suspension on the front and back,

and in those you can either have a dependent system,

where a rigid axle binds the wheels,

or an independent system where the wheels

are permitted to move independently,

but the three fundamental components of any suspension

are springs, dampers, and anti sway bars.

Those are the bars that hate former MTV News reporter, Sway.

Wait, oh no, I'm being told that

they're actually just used along with shock absorbers

or struts to give a moving automobile additional stability.

Sway bars a metal rod that spans the entire axle

and effectively joins each side of the suspension together.

You suck, Sway.

Let's get back to talking about

one of three fundamental components of suspensions,

and my third favorite season, spring.

Now there's a couple of types of springs that can be used,

there's leaf springs, several layers of metal

bound together to act as a single unit,

and these are usually used on a lot of trucks.

They haven't been on a ton of US cars since '85.

There's torsion bars, here

one end of a bar is anchored to the vehicle frame

and the other end is attached to wishbone.

The wishbone acts like a lever that moves

perpendicular to the torsion bar.

When the wheel hits a bump,

vertical motion's transferred to the wishbone,

and then, through the levering action, to the torsion bar.

The torsion bar then twists along it's axis

to provide the spring force.

These are more common on European cars,

and there's coil springs,

basically a heavy duty torsion bar coiled around on an axis.

These are the most common.

Anything above the springs

and supported by 'em on the vehicle is sprung mass.

Anything below the spring between the springs and the road,

like the wheels, for example, is unsprung mass.

Unsprung mass was my nickname in college,

or it was until that fateful night

three years ago in September.

Spring stiffness effects how the sprung mass responds

while the car's being driven.

Loosely sprung cars, such as luxury cars,

swallow bumps for a smooth ride,

but they're prone to dive and squat

during braking and acceleration,

and can have body sway, or roll during cornering.

Tightly sprung cars, like sports cars,

are less forgiving on bumpy roads,

but they minimize body motion

so they can be driven aggressively, even around corners.

(engine revving)

(ding)

But you can't use just springs, you silly goose.

Springs absorb energy

but they stink when it comes to dissipating it,

that's why you need dampers.

One common dampening structure is a shock absorber.

Shock absorbers slow down and reduce the magnitude

of vibratory motion

by turning the kinetic energy of suspension movement

into heat energy that can be dissipated

through hydraulic fluid.

A shock absorber's upper mount connects to the frame

and the lower mount connects to the axle.

In a twin tube design,

the upper mount is connected to a piston rod

which is connected to a piston

and sits in a tube filled with hydraulic fluid.

Feels like I said that.

The inner tube's known as the pressure tube,

and the outer tube is known as the reserve tube.

The reserve tube stores excess hydraulic fluid.

When a wheel hits a bump in the road

and causes the spring to coil and uncoil,

energy of the spring is transferred to the shock absorber

through the upper mount, down through the piston rod,

and into the piston.

Orifices perforate the piston and allow it to leak through

as the piston moves up and down in the pressure tube.

Because these orifices are relatively tiny,

only a small amount of fluid, under great pressure,

passes through.

This slows down the piston,

which in turn, slows down the spring.

Shock absorbers work in two cycles,

the compression cycle when the piston moves down

compressing the hydraulic fluid

in the chamber below the piston,

and the extension cycle,

when the piston moves toward the top of the pressure tube

compressing the fluid in the chamber above the piston.

All modern shock absorbers are velocity sensitive.

The faster the suspension moves,

the more resistance the shock absorber provides,

so they can adjust to road conditions

and control all the unwanted motion

that can occur in a moving vehicle,

including bounce, sway, ah, I hate that guy,

brake dive and accelerating squat.

Another common dampening structure is the strut.

Basically it's a shock absorber mounted

inside a coil spring.

Struts provide two jobs,

dampening function like the shock absorbers,

and structural support for the vehicle's suspension.

They do a bit more than shock absorbers,

which don't support vehicle weight,

they only control the speed

at which the weight is transferred in a car,

not the weight itself.

The Mac Daddy of struts

is the MacPherson strut invented by Earle S. MacPherson.

No one knows what the S stands for except for Wikipedia,

which says is stands for Steele, cool.

The MacPherson strut consists of a single control arm

in a strut assembly

which allows tire and wheel to move upward and downward.

Its design allows for a reduction in a number of parts,

lowering unsprung mass, as well as smooth driving comfort.

These are pretty small, not too complicated,

and not too expensive, so they're pretty common.

They don't take up much space horizontally,

so they're super common in front suspensions

on the front wheel drive vehicles.

They do take up a lot of space vertically, though.

Another common type of front independent suspension,

the double wishbone suspension or an A-arm,

doesn't take up as much space vertically,

but is a horizontal hog.

That one guy in the comment section.

While there's several different possible configurations,

this design typically uses two wishbone shaped arms

to balance the wheel.

Each wishbone, which has two mounting positions to the frame

and one at the wheel, has a shock absorber and a coil spring

to absorb vibrations.

Double wishbone suspensions allow for more control

over the camber angle of the wheel

which describes the degree

to which the wheel tilts in and out.

(car squeaking)

They also help to minimize roll and sway,

and they provide for more consistent steering feel.

That's why double wishbone suspension's so common

on the front wheels of larger cars.

(claps) Real quick,

let's look at a couple of rear suspensions

and a split second picture of my belly button.

These are usually a little simpler

'cause you don't need to integrate the steering

for a dependent rear suspension,

if a solid axle connects with the rear wheels of a car,

then it's pretty simple,

based either on a leaf spring or a coil spring.

Leaf springs clamp directly to the drive axle,

and the ends of the leaf springs

attach directly to the frame.

The shock absorber's attached at the clamp

that holds the spring to the axle.

You can have the same basic design with coil springs

but in this case, the spring and shock absorber

can be mounted as a single unit or as separate components.

When they're separate, the springs can be much smaller,

which reduces the amount of space

that the suspension takes up.

For independent rear suspensions,

if both the front and back suspensions are independent,

then all the wheels are mounted and sprung individually,

resulting in what some ads call

four wheel independent suspension.

Any suspension that can be used in the front of a car

can be used on the rear

and versions of the front independent systems

described in the previous section

can be found in rear axles.

Of course, the rear of the car, the steering rack,

the assembly that keeps everything together

and lets ya turn, well, it's not there,

so that means rear independent suspensions

can be simplified versions of the front ones,

but the basic principles are the same.

Suspensions!

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