Automatic vs Manual Transmission


Which is better? Manual or automatic transmission? That’s a pretty interesting question This debate has been present for the last seven decades Manual and automatic transmissions are completely different technologies Which use different configurations and principles one is based on a simple grear pair while the other is based on a planetary gear set one uses a torque converter while the other uses a clutch pack we will do a logical comparison of these technologies in this video but first let’s understand the basic science of transmission an internal combustion engine produces useful torque and power only during a certain speed range due to this inherent problem of IC engines controlling the drive wheel speed by directly connecting them to the engine is not a clever idea such an approach will give the engine of very low efficiency rather we need a transmission in between so that the engines rpm can always be in the maximum efficiency range the transmission takes care of the speed variation of the drive wheels first let us see how the speed variation is achieved in a manual transmission a manual transmission is a collection of gear pairs it has three sections input intermediate shaft and output the input is connected to the intermediate shaft so the intermediate shaft always rotates at a constant speed the intermediate shaft is then connected to the output gear set you can see that the output gears will turn at different speeds due to different gear ratios however the output gears are not fixed with the output shaft and you can even see a gap between the output gears and shaft if we connect only one output gear to the shaft the shaft will have the speed of the connected gear for this the main shafts gears have a synchronizer cone teeth arrangement a hub is connected to the shaft and a sleeve slides over it just by moving this sleeve you will be able to connect the gear and shaft it might seem like a simple mechanism however during an actual operation the hub and gear will be rotating at different speeds and the sleeve gear connection is not possible as they do so first let’s make their speed the same for this we must discontinue the power flow to the transmission the use of clutch pack comes here by disengaging the clutch pack the power flow to the gear set is discontinued now a synchronizer ring with a friction cone can help to match the speed of gear with the sleeve when there is no power flow pushing the synchronizer ring against the gear will help match the speed of the gear to the hub now we can have a smooth connection after the connection clutch pack is engaged so every time you need to change the gear you must disengage the clutch this also means power discontinuation and an Associated speed drop during the gear change this is why a manual transmission drive is never a smooth experience now let’s see how an automatic transmission is different from manual transmission automatic transmission was developed to overcome the power discontinuation problem in manual transmission and it uses a planetary gearset arrangement rather than a simple gear pair you can see that a planetary gearset has two inputs and one output the basic principle of automatic transmission is simple just vary these two input speeds and you will get different output speeds to achieve this objective let’s introduce one more planetary set the output of the second connected with one of the inputs of the first set in simple words the carrier of the second set and the ring gear of the first set are a single unit this forms an interesting mechanism and is the simplest automatic transmission possible to clutch packs are introduced to arrest the motion of the ring grears when the clutch pack is pressed the corresponding ring gear will be stationary and carrier will rotate when the first clutch is pressed the green ring gear is stationary and we will get the first gear if we can turn the green ring gear the output speed will increase to achieve this you must release the first clutch and engage the second clutch the green ring gear will rotate as it is connected to the carrier of the second set it is worth noting that the first clutch is being released at the same time that the second clutch is engaged so there is no loss in power transmission for different output speeds are possible with two planetary set arrangement to learn the details of it check out our detailed video on automatic transmission by using three planetary gear sets in series we will be able to achieve six different speeds and a reverse the beauty of the automatic transmission is that by engaging the proper two clutch packs we can achieve different output speeds now let’s compare these two technologies directly as discussed in the automatic transmission there is no abruption of power flow so you will get a smooth driving experience computer controlled operation of the automatic transmission makes the driving even simpler it is clear that the manual transmission technology is much simpler than the automatic it has fewer components and is easier to repair on the other hand automatic transmission is a tightly packed arrangement when it comes to heavy duty operations manual transmissions offer more durability due to this reason almost eighty percent of heavy duty trucks use manual transmissions the way automatic and manual transmission handles the condition of braking is quite different and interesting in manual transmission driving before you press the brake pedal the clutch pedal must be pressed completely this way the engine rotation and wheel rotation are separated completely and the sudden cease of the wheel will not be transmitted to the engine however there is no clutch pedal in an automatic transmission car so to separate the engine rotation from the transmission a torque converter is used this is a fluid coupling which allows slippage so a torque converter helps automatic transmission handle the braking scenario without the need of a clutch pedal however a torque converter is a good heat generator which in turn reduces efficiency of the vehicle as a result automatic transmission vehicles tend to become less fuel-efficient than manual vehicles however the modern torque converters have overcome this problem it is our hope that the next time you plan to purchase a four-wheeler you will be able to choose the proper transmission technology according to your needs to miss our video on DSG transmission which has the best features of automatic and manual transmissions combined please consider helping us at patreon.com so that we can sustain our educational services thank you