Does an Automatic Car Have a Clutch? The Ultimate Clutch Guide for Automatic Car Lovers!

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Does an Automatic Car Have a Clutch

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Automatic or manual is one of the biggest questions car buyers ask around the world, especially in the 21. Century. Well, that’s unless you live in the States where automatic transmissions have been the most popular choice for almost 100 years. And what the whole automatic versus manual debate is actually about, is clutch or no clutch.

An automatic car does not have a clutch pedal, but it still has a clutch. In a manual car, the driver engages or disengages the clutch using the clutch pedal, and manually changes gears. In an automatic car, the clutch is operated by automatic shift solenoids so the driver doesn’t have to do it. The automatic transmission also changes gears.

Does an Automatic Car Have a Clutch

Understanding Automatic Cars

An automatic car is a vehicle where the transmission shifts between each gear by itself, or automatically. The transmission also operates the clutch or clutch packs. That means the driver only has to pick between forward (Drive), Reverse, or Neutral. And even that is done without a clutch.

All that eliminates the H pattern shifter, and the clutch pedal. The only thing the driver needs to do is pick between Drive, Reverse, Neutral, and Park. Essentially, the driver just tells the transmission in which direction he wants to move and the transmission does everything else.

Types of Automated Transmissions Used In Cars Today

There are several types of automated transmissions out there today. The first one is the conventional automatic with a torque converter. That type of transmission has been installed in different vehicles for a good part of 100 years. The second most common type is a double-clutch automatic transmission. That transmission doesn’t have a torque converter, and the gears are pretty much the same as they are in manual transmissions.

Then we have automated manual transmissions. An automated manual transmission is exactly the same as a manual transmission. But in this case, the clutch and the gear shifting are done by automated solenoids instead of the drivers. And then we have CVT (continuously variable) transmissions. A CVT transmission doesn’t have gears, but it does have a clutch. However, the clutch is centrifugal and is engaged by the engine rotation instead of electronically or by the driver.

How Does an Automatic Car Work

The automatic transmission has multiple sets of planetary gears. Each planetary gear set corresponds to one gear. And on each of the gear sets is a clutch pack. When the transmission wants to shift from second to third, it disengages the second gear clutch pack and engages the third gear clutch pack. All this is done without any driver input.

What shifts those gears are hydraulic solenoids or actuators. In older cars, those solenoids were controlled mechanically with engine speed and throttle input. But today, they are controlled electronically using the transmission control module.

And then we have the torque converter. The torque converter is made so that the engine and the transmission gears don’t have a direct connection. Instead, the two transfer rotational forces using hydraulic fluid which passes through the torque converter turbine.

The faster the engine turns, the higher the hydraulic fluid pressure and the faster the wheels spin. That same fluid pressure is used to engage and disengage shift solenoids.

How Does an Automatic Car Work

Differences Between Automatic and Manual Cars

There are a few differences between automatic and manual cars. First is that automatic cars have multiple clutch packs, one for every gear. A manual transmission only has one clutch for all gears that sit between the engine and the transmission. The automatic transmission then uses planetary gears, while manual transmissions use standard spur gears.

Also, in an automatic transmission the torque converter is used to decouple the engine from the transmission. It does that by lowering the fluid pressure as the RPMs drop to the point where it’s not enough to move the vehicle. But in a manual vehicle, the driver needs to push the clutch pedal in to decouple the engine. The driver also has to push the clutch in each time he wants to change gears.

The Role of a Clutch In a Car

A clutch is essentially just two friction pads where one is attached to the engine and the other one to the transmission (wheels). The clutch is used to decouple the engine and allow for a gradual engagement between the engine and the transmission. The two parts of the clutch are the friction plate and the pressure plate.

The friction plate is made of the same material as brake pads and the pressure plate is the same material as the brake rotors. If there was no clutch, the vehicle would start moving as soon as you turn the engine on. Or if you start it in neutral, the engine will stall as soon as you engage a gear. That’s actually what happens if you release the clutch too fast.

Instead, you gradually release the clutch in order to gradually increase friction between the pressure plate and the friction plate. By the time you fully release the clutch, the engine speed and transmission speed are synchronized. But in an automatic transmission, the clutch packs are used to engage and disengage gears instead of decoupling the engine. In an automatic transmission, the decoupling is done by the torque converter.

Role of a Clutch In a Car

How Does a Clutch Work

A clutch in a manual transmission vehicle is only used to decouple the engine from the transmission. The clutch is made of two parts. The first is the pressure plate which mounts to the engine. The second part is the friction plate which bolts to the transmission. On the pressure plate, there are flexible fins with a ball bearing in the middle.

Leaning against that ball bearing is a fork that’s attached to the clutch pedal. As the driver pushes the clutch pedal, that fork bends the fins on the pressure plate and pulls it away from the friction plate. Without any contact between the pressure plate (engine) and the friction plate (transmission gears), the engine is not decoupled from the wheels.

How Does a Clutch Work

Why Is a Clutch Important In a Car

A clutch is important in a manual car because it would be undrivable without it. As we mentioned earlier, without a clutch, the vehicle would start moving as soon as you crank the engine. Or it would stall as soon as you engage a gear, not to mention, you would quickly destroy those gears.

A clutch assembly is an infinitely simple and cheap design to solve the problem of safely engaging the engine with the transmission. Another use of the clutch is to shift gears. When shifting gears it’s important to remove load from the gears and you do that by pushing the clutch pedal in and decoupling the engine from the transmission. That allows smooth shifts without any gear grinding or clunking.

In an automatic transmission, the clutch packs are the best way to engage and disengage different gears. Instead of having a complicated mechanical contraption that would shift the gears in an H pattern for you, the clutch pack simply engage or disengage. That’s made possible by the torque converter which serves as an automatic engine decoupling mechanism.

Signs Of a Bad Clutch In an Automatic Transmission

The main sign of a bad clutch in an automatic transmission is slipping. That’s a sign that the clutch packs are worn out and are not making enough friction to translate engine power to the wheels. If you notice that your RPMs are rising when you push the gas pedal, but the vehicle isn’t accelerating at the same rate, it means the clutch is slipping.

Another sign is delayed shifting. As we know, the clutch packs are used to engage different gears. And if the clutch packs are worn out or damaged, they will have trouble engaging which leaves the vehicle in neutral for a long time, or the vehicle refuses to shift in the first place. And the late stages of clutch failure you might hear some grinding noises coming from under the vehicle.

Do Automatic Cars Have a Clutch

The clutch pack in an automatic car is virtually the same as those found in motorcycles. Just like in motorcycles, the clutch pack sits in transmission fluid, whereas in a manual vehicle, the clutch is dry. Then, each clutch pack has multiple friction plates where one friction plate is brake pad material and the second is brake rotor material.

The brake pad material is attached to one shaft, and the brake rotor material plates are attached to another shaft. The two shafts are the input and output shafts. And then, the friction between those plates is what engages different gears. If the vehicle shifts into the second, the clutch pack sitting on the second planetary gear set squeezes and engages the input and output shafts through the gear set.

Exploring the Transmission System In an Automatic Car

Understanding the Torque Converter

The torque converter sits exactly between the engine and the transmission. The torque converter is made up of three parts. The first is the impeller which is attached to the transmission, the second is the stator which locks the input and output shafts, and the third is the turbine attached to the engine.

As the engine and the turbine spin, transmission fluid is forced through it. That fluid then goes through the stator and into the impeller. As engine speed rises, so does the amount of fluid passing through the turbine, and the pressure it makes on the impeller. When the pressure rises enough, the impeller will start turning, and the vehicle moves. The whole process is entirely mechanical but also doesn’t require any control modules or driver input.

Differences Between a Clutch In a Manual Car and a Torque Converter In an Automatic Car

The main difference between a clutch and a torque converter is that the clutch makes a direct physical connection between the engine and the transmission. If you release the clutch pedal, the engine and the transmission are in perfect sync as long as the clutch isn’t slipping. And when you want to stop the vehicle, you have to push the clutch pedal to decouple the engine.

However a torque converter doesn’t make a physical connection, and the whole rotation transfer between the engine and the transmission is done through fluid and fluid pressure. In other words, the decoupling of the engine is done through engine speed. If engine speed is low, there isn’t enough fluid pressure to turn the wheels, and the engine is essentially decoupled.

Pros and Cons Of Automatic Cars Without a Clutch

The main advantage of driving an automatic car without a clutch is that it’s infinitely easier to drive. And if they are easier to drive, they are also safer. The biggest problem for new drivers in Europe is operating the clutch and the transmission, and the automatic eliminates both.

As far as old torque converter automatic transmissions go, that’s the only advantage. But if we talk about modern automatic transmissions, they are also considerably faster than manuals. They also have better fuel economy and are better for the environment.

Disadvantages Of Driving an Automatic Car Without a Clutch

The only two disadvantages of modern automatic transmissions are that they are more expensive to buy than manuals and that they don’t engage the driver as much. But that second drawback is something only a car enthusiast will consider. For the average driver, the fact that they are more expensive to buy is the only drawback. But they are also easier to sell and hold their value better, so there is that.

But when talking about old automatic transmissions, those made before the 2000s, they are riddled with disadvantages. First off, the vehicle puts much less engine power on the rear wheels. Plus the time it takes them to shift is much slower than the time it takes to shift a manual. That makes them significantly slower. And because they lose so much power, they also burn much more fuel.

Who Should Consider Driving an Automatic Car Without a Clutch

In today’s day and age when talking about modern cars, virtually everyone should get an automatic car. Only the true enthusiast who knows how to value manual transmissions and who finds enjoyment in driving a manual car should avoid the automatic. But other than for those people, the automatic is better for everyone else.

The automatic is significantly easier to drive, it’s safer and it’s endlessly more comfortable. On top of that, it’s also more economical, and even faster. And even the higher purchase price is neglectable when we consider that the vehicle will depreciate less.

Conclusion

In the end, the main point is that automatic vehicles do have a clutch, as a matter of fact, they have multiple clutches. But they don’t have a clutch pedal. Instead, the clutches are used to engage and disengage gears but that’s all done automatically without any driver input.

The torque converter in an automatic transmission essentially serves the same purpose the clutch serves in a manual transmission vehicle. That purpose is to decouple the engine from the transmission. And of course, the torque converter does that automatically, again, without any driver input.

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