Nissan Micra hatchback has been in the Indian market for a while, but hasn’t managed to grab a major share of the B segment sales. The company recently unveiled the soon-to-be-launched new Micra, which tries to make an improvement in multiple key areas. An important inclusion is the constantly variable transmission (CVT) transmission – a segment first. We drove the new Micra CVT around the city of Madurai and bring to you a detailed insight into the technology.
Nissan was an early mover in the area of CVTs and started offering the technology in the market way back in 1992. In the next decade, the company made significant progress towards improving the efficiency of this technology. As a result, in 2002, Nissan became the world’s first company to develop CVTs for high-torque engines by pairing it with engines as large as 3.5 l.
The technology has found good acceptance among consumers too, as it offers higher fuel efficiency than conventional automatic transmissions. Another advantage, which might appeal to some consumers, is that CVTs do not transmit any shift shock as experienced in manual or automatic units, when shifting gears. The third generation of CVT from Nissan has now been readied to be paired with Micra’s 1.2 l petrol engine as the company prepares for an aggressive growth target in the coming years.
The Micra, being the only small car offering from Nissan, will play a key role in the company’s plans to sell one lakh vehicles in India this year. Being a substantial facelift, the new Micra feature sharper exteriors, NVH reduction, updated interiors, USB, Bluetooth and Aux-in ports in addition to the CVT.
The new transmission, however, will be available only with the petrol engine. Needless to say, the theoretical potential for the technology is immense as our cities become increasingly crowded. CVT not only offers ease of operation but also a considerable increase in fuel economy, one of the key aspects for any vehicle today.
CVT – THE TECHNOLOGY WITHIN
Unlike manual transmissions, CVTs do not feature fixed gear ratios and can instead automatically select the best suited transmission ratio without any steps, making it a seamless or step-less transmission. A CVT primarily consists of two pulleys, the width of which is adjusted to change the arc radius of the steel belt running between them, leading to a change in transmission gear ratio.
The CVT in the new Micra comes as a segment first in the country and is also the most compact unit made by Nissan. Over the years, Nissan has developed an expertise in CVT development and has been using the technology in its cars globally. What’s important here is that the technology is now being launched in the small car segment, which is a challenging segment to be in the Indian market.
At the media drive of the vehicle we got a chance to talk at length with Chikuya Takada, Head of Product Planning, Nissan Motor India Private Limited, who gave us an insight into the development of the new generation of CVT transmission.
One of the multiple changes is the inclusion of sub-planetary gears, which provide a wider transmission ratio. Inclusion of sub-planetary gear in a CVT is a global first for Nissan and allows it to deliver a gear ratio of 7.3, the highest transmission ratio presently across the world. The advantage of this wider ratio is that the engine can operate in a better optimised rpm range in various conditions, leading to higher fuel efficiency. The steel belts in the transmission too are made to last about 100,000 km or more and only needs an oil change at the same distance mark.
The unit is also equipped with an adaptive shift control system, which can automatically adjust the optimal operating range depending on road conditions and driver inputs. The system can make adjustments for more than 1,000 patterns, resulting in the best possible efficiency at any given time or speed. Claimed fuel efficiency for the Micra with this CVT is 19.34 km/l, which is significantly higher than its sibling equipped with a five-speed manual transmission.
With efficiency being of paramount importance, engineers used multiple methods to lower friction and weight of the unit. At the same time, they also had to ensure smaller dimensions so that the unit could be used in small cars such as the Micra. In order to achieve this, the pulleys used in the CVT were made 13 % lighter than the earlier version and smaller in size too, resulting in a direct reduction of fuel consumption.
Takada said he’s particularly proud of this technology as it is compact, lighter and more efficient than any other transmission in its segment. An interesting change in the layout is that some components, which were earlier immersed in oil are now operating without oil. The reason behind this change is that movement through the oil also creates some friction but movement through air creates far lesser friction, allowing for a reduction in overall friction reduction within the unit. Moreover, the oil pump being used to provide hydraulic power for shifting too has undergone a size reduction and features a greater lock-up area for enhancing fuel efficiency.
Lock-up in an automatic transmission’s torque converter allows for direct and quick transfer of engine power and improved fuel economy. In a CVT, the benefit of lock-up is only during start-up. The XTRONIC CVT has precise control over ratio changes to extend the lock-up operating area to low-speed range, improving the fuel efficiency further. The flat torque converter too is 10 % smaller in size now to enable pairing with compact engines.
The overall technology as explained to us by Takada was impressive, especially due to the fact that Nissan has developed the CVT technology at a fast rate and in a manner that it can presently be deployed in a variety of engines with different sizes. This is one of the key reasons why the company is the first to offer the technology in the B segment in India.
THE ON-ROAD EFFECT
During our drive we were to first head to the temples of Madurai and then out to the highway, which meant driving through narrow roads and heavy traffic. The new Micra’s CVT was at its best in this territory and negotiating the stop & go traffic was a lot easier. This same transmission is found in the Sunny sedan and works better with the larger motor but didn’t throw up any issues in the Micra either.
The technologies explained earlier work in great harmony to ensure that there is less lag during start-offs, making city driving easier. Unlike most CVT units, the rubber band effect or the lag is less pronounced in the Nissan unit. The cure lies in a tiny button on the side of the shift lever, which engages sports mode. This improves throttle response as the hurriedness of the unit to lower engine revs reduces considerably. This also helps overcome the lack of low-end power of the engine to an extent. Mid-range power delivery though is good and we would suggest sticking to sports mode whenever on highways.
Out on the highway, moderate acceleration works fine but hard throttle inputs highlight the lag, requiring overtaking manoeuvres to be planned properly. The ride quality too is claimed to have been improved to suit Indian roads and we found it acceptable, although a bit on the firm side. The overall driving experience was positive and the Micra showed a significant progress in the right direction. As a city car, the new Micra with CVT is quite appealing, but it misses out on offering ample involvement for the driver. However, it does very well in the comfort and efficiency parameters.
The facelift Micra is a significant improvement over its predecessor, beyond the inclusion of the CVT. The car is now better equipped to attract young consumers. Another segment first inclusion in the new Micra is the LED tail lamp, which retains the external unit design but the LED cluster within offers a more sophisticated look now. Another major change is the new seat trims and the piano black centre console (in CVT variant), unlike the all over grey interior of the earlier car. The layout looks premium and adds a premium feel to the cabin.
Nissan made it clear that they want to focus on the premium compact segment, as that offers great potential. With the new Micra they’ve struck almost every right chord to make it appealing against tough competition. From a technology perspective, the complete packaging is praiseworthy but being India, the key to the new model’s success lies in the pricing. Nissan is yet to reveal the prices for the facelift Micra and if they get that right, the small car could play a big role in Nissan India’s targeted goal of one lakh unit sales in 2013.
Text: Arpit Mahendra
Photo: Bharat Bhushan Upadhyay