Being a mechanical engineer with automobile as a subject I thought I may give some detail and opinion on this bike...Centra
It is a bike designed and produced by TVS motor company....
Basic Design features
Engine & Transmission
Type 4-stroke
Cubic Capacity 99.8 cc
Max Power 5.59 KW (7.5 bhp) @ 7500 rpm
Max Torque 7.5 Nm @ 5000 rpm
Bore x stroke 51 mm x 48.8 mm
Compression Ratio 9.3:1
Transmission 4 speed constant
The TVS Centra’s central theme is to capture the attention of the mileage and value-for-money conscious entry-level bike buyer .
A large fuel tank,
very beautiful tail lamps and front lamps
chubby body panels,
larger (than is the norm in this segment) bikini fairing and headlamp housing,
broad seat and
the puny tyres are all clearly features that TVS hopes will attract the entry-level bike buyer
The new VT-i engine technology is the first time that the concept of variable ignition timing has been applied to such effect in a two-wheeler engine.
Centra’s VT-i engine revolves around three primary parameters that ensure optimum engine efficiency, which, in turn, enables the bike to squeeze out the most mileage from every drop of fuel.
The three parameters are:
Friction reduction,
complete combustion of fuel,
controlling the amount of fuel to exactly meet the driver’s requirements
and, thereby, eliminate wastage of fuel.
Lower friction and complete combustion of fuel also ensures lower emissions.
VT-i engine’s technological prowess comes from the microprocessor control system that features four different ignition maps to handle specific requirements of the rider, including a map that enables the engine to warm up quickly during a cold start. The microprocessor, a kind of engine control unit, senses the engine requirement, based on sensors that feed it information, such as engine temperature and rpm level, and adjusts the ignition timing accordingly. As a result, the engine is able to offer high fuel efficiency and an ultra wide torque band, while still coming up with a decent 7.5 bhp of maximum power.
During cruising and low-throttle operation, the microprocessor, and so the engine, is programmed to follow an economy ignition curve, thereby delivering the highest fuel economy. Other ignition curves are programmed to deliver different requirements of the customer such as cold starting, high acceleration and so on. Dual mapping was a feature that TVS was already offering in the Victor. The dual mode engine operation ? economy and power ? was, therefore, already available.
Centra has also been able to avoid fuel wastage during cold starts by giving the engine a new temperature sensor and a third ignition timing curve to quicken the engine warm up function for optimum combustion and near-zero fuel wastage.
In the Centra’s VT- engine, the timing of the two sparks from the same spark plug are controlled by the microprocessor, thereby, ensuring a total burn.
So, together with the processor’s ability to bring up the engine to optimum operational temperature, the twin sparking, and differential mapping for economy and power modes, the engines produce a wide torque curve and better fuel efficiency. Despite this high focus on fuel efficiency, the Centra’s engine is also refined and manages to beat most of the competition in its sprinting ability.
In the Centra, the fuel wastage issue has been further addressed by cutting fuel intake by the engine during the deceleration of the vehicle.
Excess fuel tends to get wasted during deceleration, as the air supply to the engine is reduced, even as it continues to suck in fuel. In the VT-i engine, the cut off controller sensor senses deceleration and operates a solenoid valve to allow air from the air filter to flow in, thereby reducing fuel wastage.
Another fuel-efficiency boosting parameter ? friction reduction ? has been achieved through a combination of new, unique technology features. The VT-i engine manages to nearly eliminate friction, which usually causes considerable loss of mechanical efficiency in conventional engines.
The exterior surface of the piston in the VT-i engine is coated with tin that boosts its anti-friction property. The piston rings are also specially-designed thin section rings. The combination of the two features reduces friction and improves the mechanical efficiency of the VT-i engine.
Further, in the VT-i engine, the valve rocker, which is a mechanical device that allows the camshaft to actuate the inlet and exhaust valves uses a roller cam follower to cut down friction.
Conventional engines suffer from friction caused by the mechanical transfer of energy. The increased mechanical efficiency of the VT-i engine translates to better torque delivery at low engine speeds and boosts fuel economy.
It come up with an amazing fuel efficiency of about 70 km per litre in city conditions.
The handling and ride comfort is superb compared to other bikes in same level
You feel quite comfortable cornering
Its pricing is right at Rs 40000
The main cons for this bike is
Inconsistent fuel average (it ranges from 50 to 80 kmpl)
Cost ....surely a person may feel it heavy on his pocket to give 40000 bucks for 100 cc bike
Brakes....front one could have been 130mm drum
Petrol tank which hits the knees of a tall rider