Auto-Engine

• Automotive power transmission systems are critical elements of any automobile. The design of power transmission systems is of critical importance to the overall vehicle system performance, as it affects not only performance characteristics such as torque and acceleration but also directly affects fuel efficiency and emissions.
• According to the Chamber of Automotive Manufacturers of the Philippines Inc. (CAMPI ) and Truck Manufacturers Association (TMA) showed that 37,683 units were sold since November 2023 in PH
• 7.6% YoY Increase in the car sales in the country
• Automatic Transmission

  In vehicles, a transmission is crucial for transferring power from the engine to the drive shaft and differential, allowing the wheels to turn. This system adjusts torque, speed, and direction by modifying transmission ratios, and facilitating high-torque starts. Unlike manual transmissions, an automatic gearbox, or automatic transmission system, operates without manual gear switching.
• Automated Manual Transmission (AMT) systems, derived from manual transmissions, automate clutch operation and gear shifting. Vehicles equipped with AMT lack a clutch pedal and traditional gear lever, utilizing additional actuators on the gearbox for clutch control and synchronization ring adjustments.
• The primary function of an automatic transmission is to enable the engine to function within its specific speed range while offering a broad range of output speeds. Without a transmission, cars would be confined to a single-gear ratio, chosen to achieve the desired top speed.
• Pros of AMT include added functionalities like hill hold and launch control, low fuel consumption, and shorter switching times compared to manual transmissions. 

  However, AMT has its drawbacks, such as laggy gear shifts, limited gear ratios, increased complexity, a less engaging driving experience, and a steeper learning curve for smooth operation.
• • Examples of Automated Manual Transmission Selespeed (Alfa Romeo)
  • SMG (BMW)
  • Sensodrive (Citroën & Peugeot)
  • Allshift (Mitsubishi)
  • Quickshift (Renault)
  • Sequentronic (Mercedes-Benz)
  • Easytronic (Opel)
  • MMT (Toyota)
  • Daimatic (Daihatsu)
  • Hondamatic (Honda)
  • NAVi5 (Isuzu)
• Planetary Gear Transmission

  Planetary gear transmissions, also known as epicyclic gear systems, involve a central "sun" gear, one or more "planet" gears, and an outer "ring" gear. These gears move in relation to each other, providing various speed ratios and torque outputs.
• 1. Sun Gear: The sun gear is a prominent gear located at the center of the planetary gear system. It is typically fixed or planted on a solid component and serves as the central point of the entire mechanism. The sun gear carries torque or power from its source.
• 2. Planet Gears: These are small gears that orbit around the sun gear. They are attached to an arm or carrier that facilitates their rotation. As the planet gears rotate, the configuration of the entire system changes, resulting in different gear ratios.
• 3. Ring Gear: The ring gear is the outer component of the planetary gear system. It has teeth arranged around its circumference, and it controls the movement of the planet gears. The output torque is often derived from the ring gear.
• The arrangement and connections of planetary gears can vary depending on the system's purpose, and they are commonly used in transmission mechanisms, such as automatic transmissions. In these systems, the performance of the vehicle can be altered based on the configuration of the planetary gears.
• Parts of planetary gear system

  A) planet gear

  B) ring gear

  C) planet gear

  D) planet gear

  E) carrier

  F) sun gear

  
• Purpose and Function of Planetary Gear Transmission

  Purpose: Efficiently transmit power and torque from an input source (such as an engine) to an output, often used in automotive transmissions and other mechanical systems.

   

  Function: The arrangement of gears allows for multiple gear ratios and torque combinations, providing flexibility in adapting to different driving conditions.
• examples of Planetary Gear Transmission

  • ZF 8HP (used by various manufacturers like BMW and Audi).
  • Ford 6F35 (used in Ford and Mazda vehicles).
  • Aisin AW TF-80SC (utilized by Volvo, GM, and others).
• A dual-clutch transmission (DCT), also called a twin-clutch transmission at times, is a kind of multi-speed car transmission system that employs two distinct clutches for even and odd gear sets.
• The purpose behind a DCT is to reduce the gap between gear shifts to a minimum, with the benefits being improved performance and fuel efficiency.
• • Fuel efficient
  • Increased speed 
  • Smoother performance
  • Eliminates shift shock
  • Flexibility to operate the gear shift manually or let the car do it automatically
• Example of DCT

  • Audi R8
  • Ford Mustang Shelby GT500
  • Nissan GT-R
  • Porsche 718 and 911
  • Kia Forte GT4
  • Volkswagen GTI
• 4-speed Automatic with Hydraulic Torque Converter

  Most automatic transmissions employ a hydraulic torque converter, a device for transmitting and amplifying the torque produced by the engine. Each type provides for manual selection of reverse and low ranges that either prevent automatic upshifts or employ lower gear ratios than are used in normal driving.
• pros of 4-speed Automatic with Hydraulic Torque Converter

  • Less noise
  • Less wear on transmission components
  • Smooth clutch engagement
  • Does not need human action for the system to operate
• cons of 4-speed Automatic with Hydraulic Torque Converter

  • Higher fuel consumption, especially when it does not have a blocking system
  • Expensive maintenance
  • More fluid change needed
  • Depending on the engine rotation speed
• A 4-speed automatic transmission with a lay shaft is a type of automotive transmission that features four forward gears and incorporates a lay shaft within its design. The lay shaft, also known as a countershaft, plays a crucial role in the transmission system by helping to manage gear ratios and facilitate smoother gear changes.
• The purpose of a 4-speed automatic transmission with lay shaft is to provide a range of four gear ratios for the vehicle, enhancing its performance and fuel efficiency. The lay shaft contributes to the coordination of gear engagement, ensuring optimal power delivery and smoother transitions between gears during acceleration and deceleration.
• Pros of 4 speed automatic transmission with lay shaft:

  • Free Ratio Selection: This transmission design allows for a relatively free ratio selection, as each transmission ratio uses its own set of gears, providing flexibility.
  • Virtually Noiseless Operation: State-of-the-art gear design and manufacturing procedures suppress gear noise effectively, achieving a noise level comparable to planetary gear transmissions.
• Cons of 4 speed automatic transmission with lay shaft:

  • Limited Clutch Diameter: The clutch diameter is constrained by the distance between the shafts, restricting certain design aspects.
  • Not specified: The text doesn't mention additional disadvantages, emphasizing the transmission's noiseless operation.
• examples of automatic transmission with lay shaft:

  • Toyota Camry- (Certain Models/ Older Camry versions)
  • Honda Accord- (Specific Accord) 
  • Ford Explorer- (Early editions)
  • Nissan Maxima- (Certain Generations)
  • Chevrolet Malibu-Certain Malibu model years.
• Continuous Variable Transmission or CVT is a transmission type that sets itself apart from manuals or conventional automatics by delivering uninterrupted pulling force during switches. It ensures smooth acceleration without different gears. The core is the variator, composed of two sets of conic discs with a running belt. Adjusting the distance between these discs seamlessly varies the transmission ratio.
• The purpose of CVT is to enable smooth acceleration and uninterrupted pulling force during switches. It utilizes a variator mechanism with conic discs and a running belt, allowing for continuous variable transmission applicable to high loads, handling up to approximately 450 Nm of torque. This addresses traditional transmission limitations, providing a more seamless and efficient driving experience, especially in scenarios with varying loads.
• Pros of Continuous Variable Transmission:

  • Improved Fuel Economy: enhance fuel efficiency, particularly in modern hybrids, and achieve around 38 mpg on average gas midsize sedans.
  • Effortless Uphill Driving: swiftly find the necessary gear ratio, ensuring smooth power delivery without the need for hard shifting.
  • Smooth Driving Experience: enable seamless driving and acceleration at any speed, avoiding abrupt downshifting during highway passing.
• Continuous Variable Transmission (CVT) has a higher cost than traditional counterparts.
• Repair and replacement of CVT can be costly, often several thousand dollars, and they may not last as long as traditional systems.
• CVT is not designed for high-performance situations and struggle with increased horsepower, making them unsuitable for sports coupes and performance cars.
• The noise perception of a CVT driver significantly differs from step automatic or mechanical transmissions, contributing to relatively low acceptance.
• Examples of Continuous Variable Transmission:

  • * Variomatic (DAF)
  • * CVT (Chrysler, Jeep, Ford, Mitsubishi, Honda)
  • * Multitronic (Audi, Seat)
  • * M-CVT (Nissan)
  • * SECVT (Suzuki)
  • * E-CVT & HSD (Toyota)
  • * LHD (Lexus)
  • * Lineartronic (Subaru)
  • * VTi (GM)
  • * Autotronic (MB)
• The transmission system in a vehicle is responsible for transmitting power from the engine to the wheels. It typically includes the gearbox, clutch, driveshaft, and differential. The gearbox allows for varying speeds and torque, while the clutch enables disengagement for gear changes. The driveshaft transfers power to the wheels, and the differential allows for different wheel speeds during turns. Overall, the transmission system plays a crucial role in optimizing engine performance and vehicle control.