How Demand for Automatic Transmissions is growing in India
Automotive transmissions in India
The transmission is an assembly of components that receive power from engine and transmit it to the wheels. It takes the output power from an engine and gives the correct torque to the drive shaft which makes the wheels rotate to propel the vehicle or to keep the vehicle stationary with the engine still running.
Today there are two different kinds of transmissions in vehicles, The manual transmission (MT) where the driver manually shifts between gears and the automatic transmission (AT) which automates the shifting for the driver. The automatic gearbox comes in different types like Automated Manual Transmission (AMT), Continuously Variable Transmission (CVT), Dual Clutch Transmission (DCT) or the conventional planetary gearbox with a torque converter.
Automatics have not been popular in the Indian market in the past, due to these being more expensive and not delivering fuel economy as good as that offered by manual transmissions. However, change is afoot. The AMT, currently being offered by some of the leading OEMs in the Indian market, has been quite a game changer. While it does not offer the smooth, seamless experience of an automatic, the AMT does offer the convenience of an automatic, with the added benefit of improved fuel economy. Worsening road congestion in cities as well as improvement in technology and fuel efficiency are increasingly driving buyers to the gearless, clutch-less convenience of automatic cars.
Automatic transmissions, first arriving in the Indian market with Hyundai i10 in 2008, and a few years later with Maruti Suzuki A-Star in 2010, shift from MTs to ATs was an expensive proposition. This perception changed with the arrival of AMT launched by Maruti Suzuki in 2014. According to The Economic Times, ATs accounted for 17.3% of passenger vehicle sales in 2019. Around 25% of sales of Maruti Suzuki vehicles use an AMT accounting to almost 400,000 passenger cars. The share of automatics in India was less than 5% three years ago in passenger vehicles. Industry experts say, the segment has the potential to account for as much as 40% of the total market in five years. The AT penetration in the Indian mass market is around 5-6 % and is poised to go up to 35-40 % over the next five years as said in an article by Auto Tech Review.
Transition from MT to AT
Transmission systems play a significant role in enabling the level of the fuel efficiency of a vehicle. Manual Transmission has been the primary transmission offered by OEMs in India for years, keeping in mind the preference of Indian customers for lower-priced options offering durability, low operating cost & maintenance, and most importantly, higher fuel efficiency.
The preference for AT has been on the rise over the last few years because of commutes getting longer with urbanisation. The Indian automotive industry traditionally, and to a large extent even at present, rely on manual transmission systems. While the top-end models across commercial vehicles and four-wheelers are offered with automatic transmissions only, most of the PV segment that still caters to the masses uses MT. AMT variants seems to be increasingly contributing to vehicle sales of companies that largely cater to the mass passenger segment in the country.
AMT uses hydraulics and computers linked the Electronic Control Unit (ECU) of the car. The gearshift patterns are pre-programmed on the ECU and work mainly on the pre-set RPM (Revolutions Per Minute) range. However, due to this reliance on pre-set RPM levels, they tend to make unplanned upshifts during overtaking manoeuvres which can be unnerving. Also, the same reason makes using an AMT on an inclination particularly tricky.
CVT uses belts or pulleys instead of traditional steel gears to offers seamless gear shifting with various ratios, which depends on engine speed or RPM. A CVT focuses on maximum fuel efficiency and continuous acceleration at the same time. But the engine noise can be loud compared to other forms of automatic transmissions.
The DCT resolved problems that automatic transmissions have like efficiency drop due to the torque-converter. It operates two manual gear sets with two clutches. One clutch and gear set are set at odd gears and the other is set at even gears. This is often packed coaxial to reduce the volume of the transmission. While one clutch is engaged the other clutch and gear set preselects a target gear. In the gearshift, one clutch disengages at the same time as the other clutch engages to make a seamless gearshift. This results in a steady acceleration with no torque drops. The gear shifting is made by a gear actuator and the clutch is operated by a Hydraulic Clutch Actuator (HCA). When the vehicle is parked both HCA disengage the clutches. This makes the vehicle rollaway causing risk or damage to the surroundings if any external force is applied to the vehicle. To prevent this, a park lock mechanism is fitted to the transmission.
Gears in transmissions
The choice of a gear drive depends on the application, its environment, and the physical constraints of the system. The operating characteristics fall into two load categories: constant torque and constant horsepower. The gearbox geometry is defined by four parameters : Horsepower transmitted, Speed of the driving gear, Ratio required (reduction or increasing), Arrangement of shafts. Gears are designed based on either bending fatigue failure or surface contact fatigue failure criteria. They must be hard to resist the contact stresses, ductile enough to resist shock loads imposed on them, due to any outside influence or dynamics built up in the system. The raw material must also be capable of resisting any stresses imposed along the shaft. Gear manufacturers are continually seeking improvements in material performance, in order to increase the power density of individual components and associated systems.
Solutions by O-Oka
In order to provide stronger gears, O-OKA Japan, is using the process of net-shape forging to produce a wide range of gears, aiming to minimize material usage and machining efforts to further downsize, imparting optimum material strength. O-OKA makes 42 million net-forged gears per annum for its OEM customers worldwide which find a variety of applications in transmissions such as manual, semi-automatic, automatic, hybrid, DCT, and EV powertrains.
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