Nissan Sunny as a brand wouldn’t sound unfamiliar to many, as it has a 45-year-old history

and has come a long way from the Datsun 1000 it was born as, to the latest 10th generation Sunny

we’ve featured here. The car was originally named by more than eight million Japanese people

through a competition run by the carmaker.

10th Generation NissaN suNNy Debuts iN iNDia

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New VeH ICLe NISSAN SUNNY

SucceSSful Brand

Over the past four and half decades, the Sunny has been one of Nissan’s most suc-cessful brands globally. Sold under differ-ent brand names such as Sentra, Pulsar and Tsuru, the car has been offered to consumers across 140 countries in various body styles, ranging from a small hatch-back to a station wagon. Overall, the ear-lier nine generations of the Sunny has accounted for a combined sale of more than 16 million units world over.

The Sunny started out as a rear-wheel drive vehicle before transitioning into a front wheel drive layout in the early 1980s. The brand was one of the few success stories during the oil crisis in the 1970s with the key USPs being high fuel-efficiency and low-buying cost. Over the last decade or so the production of Sunny stopped in Japan, which led to absence of the brand name from many large Asian markets such as China and Japan.

At the 2010 China International Auto Show, Nissan launched the 10th generation Sunny, a global compact-sedan in collabo-ration with Dongfeng Motor Company of China. The car expectedly found its way into the Indian market and is presently manufactured at the company’s plant in Chennai. The car will be sold in 170 countries under various names, including “Versa” for the United States.

Nissan didn’t have a desirable run in the Indian market until it launched its 1st car based on the “V” platform, the Micra hatchback. The Sunny is an attempt to expand in a growing yet extremely price-

sensitive segment, which pushes car manu facturers to squeeze everything they can right from supply chain to logistics. Technical innovations and features are a strong USP in this segment and on paper the Sunny seems to have a sound presence in this area.

new “V” Platform

Nissan’s “V” (Versatile) platform is an important link in the chain for Renault-Nissan towards their future strategy for developing markets such as India. The platform allows the company to bring out different body styles without the need to invest in areas such as LHD to RHD con-version, powertrain options, meeting crash test norms and emission norms of different regions. This flexibility results in significant cost-savings for both brands and added room for development of new technologies, specific to local markets.

The “V” platform is essentially an evo-lution of the older and still operational “B” platform, which is the base for cars such as Clio, Cube and Twingo. The strength and potential success of the plat-form stands tall on the foundation of the extensive knowledge sharing between Renault and Nissan. The platform pres-ently uses diesel engines and transmis-sions from Renault, while the petrol engines make do with a common Nissan-Renault engine block. Technical synergies such as these help the company save millions in the field of R&D and manufacturing.

Another technical highlight of the “V” platform is its ability to provide light-weight manufacturing through usage of plastic instead of steel in many places and lending smaller dimensions to parts such as the fuel tank. In India, Nissan has made good use of Renault’s knowledge about local sourcing and the present local-isation stands at about 80 %, which leads to great savings in areas such as logistics and import duties.

This is the first time that the Japanese carmaker has moved away from tradi-tional manufacturing in developed mar-kets to growing, yet more challenging markets, such as India. Nissan expects the “V” platform to go a long way towards fulfilling its ambitions in such developing markets.

Powertrain

The Nissan Sunny is powered by a 4-cyl-inder 1.5 litre DOHC petrol engine, code-named HR 15, from Nissan’s HR engine family. The same range of engine also finds place in other Nissan products such as the Tiida, Bluebird and Juke. The HR family of engines, along with MR series, are Nissan’s global engines for volume-selling models. The key focus for these engines is to reduce energy losses, while maximising power output and fuel-effi-ciency. The key to achieving the result though lay in overcoming several small technical humps such as friction-reduc-tion, improved combustion & cooling efficiency and better intake & exhaust

The Sunny’s exterior is easy to the eye without any radical curves and the sloping roofline helps improve aerodynamics

The HR15 4-cylinder 1.5 l engine produces 99 ps @ 6,000 rpm and a torque of 134 Nm @ 4,000 rpm with an ARAI certified fuel-efficiency of 16.95 kmpl.

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efficiency. In India, Nissan claims an ARAI-certified mileage of 16.95 kmpl.

We explain below how each technical area within the powertrain was addressed*:a. reducing friction:

a. Bore circularity matching: Cylinder bores on a conventional engine might undergo some deformation due to the axial forces, when a cylinder head is bolted to a cylinder block. On the HR engines though, the bore is exposed to circularity machining, which prevents bore deformation due to axial forces acting upon the cylinder head bolts. This leads to reduced friction between the piston ring and cylinder bore and hence a significant reduction in power losses.

b. mirror finiShing: The crankshaft and camshaft journals are finished with a polishing-tape to bring out a smoother and shinier surface, which in turn helps reducing the friction of these components.

c. offSet cylinderS: The HR engines are fitted at an off-set to reduce friction arising from the angle of the connect-ing rod, when a piston travels down into a cylinder. The smoother func-tioning of pistons enhances power output and fuel-efficiency in-turn. In addition, the engine architecture allows the piston to have a lengthier upper movement, which slows down

the piston velocity and allows more efficient usage of combustion energy, while improving thermal efficiency.

B. imProVing comBuStion efficiency:

a. PlaStic intake manifold with integrated

tumBle control ValVe: In order to make the combustion process more effi-cient, Nissan claims that the HR engines have an improved tumble control valve capable of generating optimal longitudinal vortex of the air-fuel mixture to enhance combustion stability. The cylinder walls and pis-ton crowns too are designed to induce tumble swirl. The combined result of these applications is better fuel econ-omy due to optimised air-fuel mixture consumption.

b. large caPacity egr SyStem: The EGR system directs a part of the exhaust gases to the intake manifold and hence enhances fuel efficiency, while keeping NOx emissions down. Nissan claims its enhanced combustion proc-esses such as the tumble control valve help the engine use more amounts of exhaust gases and thus return better fuel efficiency and power delivery.

c. fine SPray injectorS: It’s a well-known fact that a finer particle size of the injector’s spray helps achieve better combustion and reduce hydrocarbons. In the HR engines the 4-hole injector nozzle plate (diameter: 250 µm) is replaced with a 12-hole version (dia-

meter: 130 µm) in a multi-hole fine spray injector. The new parts help reduce the particle size by about 40 %, while increasing the range.

d. imProVing cooling efficiency: Cooling efficiency of an engine is directly pro-portional to its anti-knock capability during combustion at higher compres-sion ratios. In the HR engines, Nissan reduced the water jacket wall thick-ness around the combustion cham-bers to 4.5 mm, a reduction of about 25 % over the previous design without compromising on strength and rigid-ity. The increased room for the cool-ant thus results in better cooling.

e. m12 SPark PlugS: The HR engines use M12 spark plugs of smaller size allow-ing for added flexibility in the water jacket and thereby aiding cooling efficiency.

c. oPtimizing intake/exhauSt efficiency:

a. front intake/rear exhauSt layout: The HR family of engines sport a front intake and rear exhaust layout with long intake runners, which are claimed to be capable of increasing the torque in the low and mid-range and achieve smoother exhaust flow.

d. engine acouSticS:

a. equal length manifold BrancheS: The intake manifold on the HR engine fea-tures four branches of equal acoustic length. This design brings out sounds created by lighter and clear sounding

Internals of the HR15 engine

C-VTC controls VVT operation and controls valve timing increase torque in the range of 2,000 rpm.

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components and dampens those cre-ated by heavier parts. Nissan claims this application to significantly reduce the rough engine noise during acceleration.

b. Silent chain driVe: A camshaft drive chain creates sound when its pins come in contact with the sprockets in a conventional engine. In the HR engines the links are designed in order to engage the sprockets at points in addition to the pin, thereby resulting in better distribution of impact and lower noise.

e. reduction of PartS for lower weight

and increaSed reliaBility:

a. coolant PiPeS Built-in: The coolant dis-tribution system is redesigned to be accommodated in the block and head. Zero usage of pipes eliminates the need for external couplings and hence saves weight.

b. cracking-ProceSSed connecting rodS:

Integrally-cast con rods are lighter than conventional con rods, which are made in two parts and are separated at the eye, where they join the crank-shaft. The cracking processed con rod is manufactured in one piece after which the lower eye is cracked into two, which are joined together post the mounting process. Matching the uneven surfaces created by the crack-ing process results in a claimed pre-cise joint.

c. SerPentine auxiliary driVe: Conven-tional engines run each auxiliary com-ponent separately through individual belts. HR engines use a single belt ser-pentine auxiliary drive system to run

the AC compressor, power steering pump, alternator and other engine components. Herein, the pulleys are put in a single plane resulting in shorter engine length while usage of auto-tensioners lowers the belt load and enhances part life.

d. high-adheSion fiP gaSket and chamfer

ShaPe: “Form in place” (FIP) gaskets improve the cylinder head and oil pan sealing by creating a sealant layer of uniform thickness. Additionally, cham-fer process is used to shape mating surfaces based upon fluid dynamics due to which the extra gasket material protruding from the mating surfaces fills the chamfer to improve adhesion.

f. gearBox:

a. The Sunny has a 5-speed manual gearbox focused on providing an easy driving experience in traffic. The ratios are inclined towards being short and the gear lever slots accurately into any gear. The not-so smooth shifting of the gearbox though leaves some room for improvement.

exterior

The Nissan Sunny has been purpose-built to be a practical, value-for-money and economical family sedan and the idea is evident in its design. There are no flaring or radical lines along the body and most of the elements are quite conventional. The overall design bears a rounded theme, quite similar to the Nissan Teana.

The “V” platform focuses significantly on efficiency and aerodynamics go a long

way into achieving the objective. The drag coefficient for Sunny is 0.318, a very good number since the segment it competes in is very sensitive towards fuel-efficiency.

Overall dimensions aren’t too large and a short hood aids in manoeuvrability in dense traffic. The wheelbase is visibly longer than most cars in this segment as there’s very less overhang at both the front and rear. Boot space is fairly large at 490 litre and once again at par with most of the competition, except the Toyota Etios.

The base and middle variant get steel wheels, whereas the top XV version fea-tures alloys. Headlight units are decent and brighten up the path ahead ade-quately regardless of the beam being used. The base variant also misses out on body-coloured door handles and mirrors.

interior

Going by the claims of Nissan, the interior is a USP for the car as it is claimed to be the most spacious cabin in-class. The extended wheelbase of 2600 mm is at par with many cars from a segment above and the extra space available is clearly evident from the first-look. Trim is availa-ble in fabric and colour schemes vary for the variants.

Apart from getting generous space, backseat passengers also get a separate vent, which shouldn’t be mistaken for an AC vent. The unit simply pulls in air from the front and releases it into the rear aid-ing quicker cooling to some extent. Audio setup consists of four speakers with the

A small yet easy to use button to manually lock/unlock doors

Rear legroom is best-in-class. The sloping roof though could reduce the headroom for taller people

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ability to support Aux-In and MP3 but no Bluetooth or USB connectivity.

Headrests are adjustable for both rows and while the rear seats feature a centre-armrest the front seats miss out on it. Steering mounted controls include a vol-ume adjustment and track/source seek button. Ergonomically, the car’s interiors turn up well except the handbrake lever offset to the left and the seat backrest adjustment lever’s positioning, which makes it hard to make changes while driving.

Instrument console is the same as found in the Micra and likewise the top variant features push button ignition. The top and middle variants get an automatic climate control system, while the base model features a manual AC. Regardless of the temperature control system the AC is an effective cooling unit and quickly

cools the cabin even if the car has been standing in the sun for long durations.

The instrument console includes a speedometer and tachometer and a digital MID (multi-information-display), all of which are brightly-lit. The MID gives out information about various things such as distance-to-go, immediate and average fuel-consumption and outside temperature apart from the usual information signs.

Safety & electronicS

Nissan has equipped all variants with a balanced package of active and passive safety features. The base variant features ABS with EBD and Brake Assist; driver airbag and engine immobiliser. The upper two variants receive additional front pas-senger airbags, while the top variant gets fog lamps too. The front ventilated disc & rear drum setup does a good job of bring-ing the vehicle to rest from high speeds in panic situations.

The car is fitted with various electronic features to ease the driving experience. Electric power steering and tilt adjustment is standard. Power windows with auto down & anti-pinch function feature on the middle and top variant. The remote key houses a boot release button too which aids easier access and usability.

SuSPenSion

The Nissan Sunny is equipped with an independent front suspension featuring McPherson struts with coil springs, which

are claimed to enhance the comfort levels of the ride. A torsion beam rear axle with anti-roll bar has been designed to keep intrusions in the luggage area to a mini-mum. The suspension is mounted on sub-frames, which help lower the road noise and overall NVH levels. The suspension has additionally been designed to feature long stroke suspension travel, which improves the ride quality over bad and undulating surfaces – a boon for Indian conditions.

technical round-uP

At the outset, the Nissan Sunny seems to be just another car in the compact-sedan segment in terms of technology. We’re sure though that by now our readers would’ve realised that cars today in this segment too feature a lot of innovative technologies, which aren’t visible, yet exist. The “Powertrain” section shows the amount of technical challenges companies are faced with in the present times of stringent norms and the amount of engi-neering that goes into overcoming those challenges.

*Information for the Powertrain section has been sourced from Nissan’s Global website.

text: Arpit Mahendra

Photo: Noshad Ali

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The dashboard is well laid-out and controls are easy to reach and read

Sunny’s 490 litres boot features a low-loading point and the layout allows for good utilisation of space

Driver’s right armrest controls include power window switches, child door/window lock and main door lock

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