Variable Cylinder Management
Encyclopedia
Variable Cylinder Management (VCM) is Honda
's term for a variable displacement
technology. It uses the i-VTEC
system to disable one bank of cylinder
s during specific driving
conditions (for example, highway
driving) to save fuel
. The 2008 Accord takes this a step further allowing the engine to go from 6 cylinders, down to 4, and further down to 3 as the computer sees fit. Honda's VCM uses overhead cams as opposed to DaimlerChrysler
's Multi-Displacement System
and General Motors' Active Fuel Management
pushrod systems.
It uses a solenoid
to unlock the cam followers
on one bank from their respective rockers, so the cam follower floats freely while the valve springs
keep the valves closed. The engine's drive by wire
throttle allows the engine management computer to smooth out the engine's power delivery, making the system imperceptible. Vehicles equipped with VCM are equipped with an "ECO" indicator on the dashboard which corresponds to the VCM system's operation. Vehicles equipped with VCM also include Active Noise Cancellation (ANC) and Honda's Active Control Engine Mount (ACM) system. The ANC and ACM systems work in cooperation to cancel both noise and vibration that could occur in relation to the cylinder deactivation process. The ANC system uses the audio speakers to cancel out noise by using an opposite phase sound.
Honda
is a Japanese public multinational corporation primarily known as a manufacturer of automobiles and motorcycles.Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than...
's term for a variable displacement
Variable displacement
Variable displacement is an automobile engine technology that allows the engine displacement to change, usually by deactivating cylinders, for improved fuel economy. The technology is primarily used in large, multi-cylinder engines...
technology. It uses the i-VTEC
VTEC
VTEC is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani, and was the first system...
system to disable one bank of cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...
s during specific driving
Driving
Driving is the controlled operation and movement of a land vehicle, such as a car, truck or bus.Although direct operation of a bicycle and a mounted animal are commonly referred to as riding, such operators are legally considered drivers and are required to obey the rules of the road...
conditions (for example, highway
Highway
A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...
driving) to save fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
. The 2008 Accord takes this a step further allowing the engine to go from 6 cylinders, down to 4, and further down to 3 as the computer sees fit. Honda's VCM uses overhead cams as opposed to DaimlerChrysler
DaimlerChrysler
Daimler AG is a German car corporation. By unit sales, it is the thirteenth-largest car manufacturer and second-largest truck manufacturer in the world. In addition to automobiles, Daimler manufactures buses and provides financial services through its Daimler Financial Services arm...
's Multi-Displacement System
Multi-Displacement System
Chrysler's Multi-Displacement System is an automobile engine variable displacement technology. It debuted in 2004 on the 5.7 L modern Hemi V8...
and General Motors' Active Fuel Management
Active Fuel Management
Active Fuel Management is a trademarked name for the automobile variable displacement technology from General Motors. It allows a V6 or V8 engine to "turn off" half of the cylinders under light-load conditions to improve fuel economy...
pushrod systems.
It uses a solenoid
Solenoid
A solenoid is a coil wound into a tightly packed helix. In physics, the term solenoid refers to a long, thin loop of wire, often wrapped around a metallic core, which produces a magnetic field when an electric current is passed through it. Solenoids are important because they can create...
to unlock the cam followers
Lifter
Lifter can mean:* Ionocraft, a device that can generate thrust using ionised air with no moving parts* Tappet, part of an internal combustion engine that actuates a poppet valve through rocker arms and pushrods...
on one bank from their respective rockers, so the cam follower floats freely while the valve springs
Poppet valve
A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide...
keep the valves closed. The engine's drive by wire
Drive by wire
Drive-by-wire, DbW, by-wire, or x-by-wire technology in the automotive industry replaces the traditional mechanical control systems with electronic control systems using electromechanical actuators and human-machine interfaces such as pedal and steering feel emulators...
throttle allows the engine management computer to smooth out the engine's power delivery, making the system imperceptible. Vehicles equipped with VCM are equipped with an "ECO" indicator on the dashboard which corresponds to the VCM system's operation. Vehicles equipped with VCM also include Active Noise Cancellation (ANC) and Honda's Active Control Engine Mount (ACM) system. The ANC and ACM systems work in cooperation to cancel both noise and vibration that could occur in relation to the cylinder deactivation process. The ANC system uses the audio speakers to cancel out noise by using an opposite phase sound.
Vehicles equipped with VCM
- 2003 Honda InspireHonda InspireThe Honda Inspire is a luxury sedan introduced by Honda in 1990 and based on the Honda Accord chassis. The first Inspire debuted in 1990 as the Accord Inspire, a sister nameplate to the Honda Vigor, then the Honda Vigor was exported to the USA as an Acura...
- 2005-2007 Honda Accord Hybrid (JNA1)
- 2005+ Honda OdysseyHonda OdysseyHonda Odyssey can refer to three motor vehicles manufactured by Honda:* Honda Odyssey , a minivan sold in Japan and other parts of the world* Honda Odyssey , a minivan sold primarily in the United States and Canada...
EX-L and Touring Models only (J35) - 2006+ Honda Civic HybridHonda Civic HybridThe Civic hybrid, based on the seventh generation Civic, was first introduced to the Japanese market in December 2001. Honda claimed it was the most fuel efficient 5-passenger gasoline-powered production vehicle in the world at the time. It was introduced to the U.S. in spring 2002 as a 2003 model...
- 2006+ Honda PilotHonda PilotThe Honda Pilot is a mid-size crossover SUV. The Honda Pilot is built in Lincoln, Alabama, and was also produced in Alliston, Ontario, Canada up until April 2007. The first generation Pilot was released in the summer of 2002 as a 2003 model, and in 2006 it received new front and rear fascias, a...
2WD Models only (J35) - 2008 Honda AccordHonda AccordThe Honda Accord is a series of compact, mid-size and full-size automobiles manufactured by Honda since 1976, and sold in a majority of automotive markets throughout the world....
except EX-L V6 6MT Coupe - 2009+ Honda PilotHonda PilotThe Honda Pilot is a mid-size crossover SUV. The Honda Pilot is built in Lincoln, Alabama, and was also produced in Alliston, Ontario, Canada up until April 2007. The first generation Pilot was released in the summer of 2002 as a 2003 model, and in 2006 it received new front and rear fascias, a...
(all models) - 2010 Honda AccordHonda AccordThe Honda Accord is a series of compact, mid-size and full-size automobiles manufactured by Honda since 1976, and sold in a majority of automotive markets throughout the world....
V6 (except EX-L V6 6MT Coupe) - 2011 Honda OdysseyHonda OdysseyHonda Odyssey can refer to three motor vehicles manufactured by Honda:* Honda Odyssey , a minivan sold in Japan and other parts of the world* Honda Odyssey , a minivan sold primarily in the United States and Canada...
V6 (all models)
See also
- Variable displacementVariable displacementVariable displacement is an automobile engine technology that allows the engine displacement to change, usually by deactivating cylinders, for improved fuel economy. The technology is primarily used in large, multi-cylinder engines...
- General Motors' Active Fuel ManagementActive Fuel ManagementActive Fuel Management is a trademarked name for the automobile variable displacement technology from General Motors. It allows a V6 or V8 engine to "turn off" half of the cylinders under light-load conditions to improve fuel economy...
(AFM) - ChryslerChryslerChrysler Group LLC is a multinational automaker headquartered in Auburn Hills, Michigan, USA. Chrysler was first organized as the Chrysler Corporation in 1925....
's Multi-Displacement SystemMulti-Displacement SystemChrysler's Multi-Displacement System is an automobile engine variable displacement technology. It debuted in 2004 on the 5.7 L modern Hemi V8...
(MDS) - Daimler AG's Active Cylinder ControlActive Cylinder ControlDaimler AG's Active Cylinder Control is a variable displacement technology. It debuted in 2001 on the 5.8 L V12 in the CL600 and S600...
(ACC)