Honda Develops a New 125cc Global Standard Engine

According to Honda newsletter, Honda Moto Co. Ltd. of Japan has developed a new next generation 125cc engine. This engine is mainly developed for Honda’s next generation scooters and it may find place on some automatic motorcycles. Honda has made this 125cc, 4-stroke, single cylinder, liquid cooled engine more compact and light weight compared to its earlier 125cc engines.

It has 25% better fuel efficiency compared to any conventional 125cc engine and produce lesser CO2 which will help Honda to comply with upcoming stringent emission norms worldwide.

The better fuel efficiency is attributed to wide range of low friction technologies which Honda has incorporated in this engine such as, first adoption of a shell type needle bearing for the rocker arm shaft, offset cylinder and an intelligent control system to lessen friction during power generation.

The new engine will find its way on variety of 125cc scooters which Honda has plan to sell in many countries around the world in the beginning of 2012. As if now it is not known that which countries will get this new 125cc engine, but India can expect this engine on Honda’s next powerful scooter for India which it has plan to launch in 2012.

According to Honda newsletter following are the main features of engine

Adoption of a Wide Range of Low-Friction Technologies

  • Offset cylinder reduces friction caused by the contact between the sliding piston and the cylinder.
  • Piston weight has been thoroughly reduced through CAE analysis.
  • A spiny sleeve with minute spines on the outer surface of the cylinder sleeve has been adopted to reduce oil consumption and improve cooling performance.
  • A shell-type needle bearing is used for the rocker arm shaft to reduce friction.
  • Smaller and lighter rollers together with an optimized cam profile and valve spring load.
  • Radiator core with high cooling efficiency has been adopted (approximately 1.5 times the efficiency of current models). This enables a smaller and lighter cooling fan on the back of the radiator and reduces friction loss by approximately 30%.
  • Transmission oil capacity is reduced 25% compared to current 125cc engines through modifications inside the transmission case in order to lower the oil agitation loss.
  • Bearings for each of the three axes in the transmission unit are exclusively designed according to the load received, resulting in an optimal set of specifications that lessen the rolling resistance inside the bearings. Friction loss has been cut by approximately 20% compared to the current engine (when running at 50km/h).

Excellent Combustion Efficiency

  • A compact combustion chamber design incorporates burning velocity and cooling performance suitable for an engine that emphasizes torque characteristics in the rpm ranges actually used by a 125cc scooter.
  • The air intake port connection to the combustion chamber has been redesigned into a smoother shape that does not impede the flow of the fuel-air mixture.
  • Optimal ignition timing is set due to improved knocking resistance created by a highly efficient radiator and a water jacket that efficiently cools the combustion chamber.

Intelligent Electronically-Controlled ACG starter

  • Smooth and remarkably quiet start has been realized through an electronically-controlled ACG starter, which serves as both a self-starter and a dynamo. An advanced idle stop system has also been realized.
  • Intelligent electronic control improves fuel efficiency through the reduction of friction during power generation.
  • A swing-back that returns the crank to its position before air intake is electronically controlled for easy restart, while a decompression mechanism mitigates cranking resistance arising from compression during engine start.

Excellent Transmission Efficiency

  • A wide-ratio continuously variable transmission with V-belt (V-Matic) utilizes a drive belt made of newly developed high-elasticity rubber. Both excellent fuel efficiency and quietness are achieved through the efficient transmission of driving force by optimizing the lateral pressure applied to the belt, along with the durability of the belt.

– Mahavir Kothari