Honda's VCM: Power at No Extra Cost of Fuel

Honda established another benchmark in fuel saving technologies by re-inventing the internal combustion engine design and implementing the Variable Cylinder Management technology to deliver the most outstanding power without actually affecting the fuel economy. Combined with the brilliant i-VTEC Engine, this technology can save fuel considerably while reducing the CO2 emissions and particularly most useful during long distance traveling.

This technology works according to the driving habits and conditions. VCM automatically deactivates 1 out of 3 or 1 out of 2 cylinders in case of 6 cylinder engine. The technology closes the valves in two or three cylinders as per the need and stops the fuel supply so that these cylinders do not involve in combustion process. Technically, this makes the engine smaller, producing required output and reducing the CO2 emissions. The technology operates based on seven different driving conditions and in three stages. Normally for city cruising, when the power requirements are not much, combustion from three cylinders out of six is enough to fulfil the required speed. Even while braking, the effect remains the same keeping three of the cylinders inactive.

However, as soon as the driver presses the accelerator for better speed requirements, VCM allows all the cylinders to operate normally providing ample power. Generally on a highway, acceleration is required only for an instance to overcome the friction. Later on the vehicle requires only a power to maintain the cruising speed which the VCM knows very well and as such it deactivates three cylinders instantly. The third stage of VCM comes into action when the cruising speed needs a little more acceleration in case of overtaking which activates one more cylinder making total of four out of six cylinders active and satisfies the driver's acceleration needs. Right after the acceleration is achieved, the engine runs back on three cylinders again. By switching between the cylinders, power is made available just when there is a need while keeping a close eye on fuel consumption.

An engine with VCM Technology also helps in eliminating pumping losses in the engine cylinders by preventing the formation of air resistance during the pumping of intake and exhaust gases from the cylinder. As claimed by Honda, this technology also reduces loss generated due to friction from valve cams and springs. But Honda needed expert engineering skills to implement this technology. The rocker shafts were needed to have hydraulic pathways to allow the pin to slide and stop the valves from operating and thereby deactivating the required cylinders. The VCM technology was first featured on 3.0L V6 engine with two stages of switching between three and six cylinders but later on developed on a 3.5L V6 with three stages combined with VTEC technology.

Saving a fuel always had to compromise with power before this technology evolved but Honda's VCM certainly proved that impossible is nothing!

John, an automotive fellow, having keen interest in automotive industry, writing articles regarding Honda and Honda parts during these days. He likes to share his knowledge of interest with people with great enthusiasm.


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