What is a Variable Cylinder Engine?
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Variable Cylinder Engine, abbreviated as VCM (Variable Cylinder Management), is a variable cylinder management technology developed by Honda. It can switch the 3.5L V6 engine between 3, 4, and 6 cylinders by shutting down individual cylinders, allowing the engine displacement to vary between 1.75-3.5L, thereby significantly saving fuel. Below is an introduction to variable cylinder technology: 1. Variable cylinder technology is generally suitable for multi-cylinder, large-displacement models such as V6, V8, and V12 engines. Since most daily driving situations do not require high power output, large-displacement multi-cylinder engines can be somewhat wasteful. Hence, variable cylinder technology was developed to control and shut down a portion of the cylinders when high power output is not needed, reducing fuel consumption. 2. During vehicle starts, acceleration, or climbing, when high power output is required, the engine will engage all 6 cylinders. 3. During medium-speed cruising and low engine load conditions, the system will operate only one cylinder bank, i.e., three cylinders. During moderate acceleration, high-speed cruising, and gentle slope driving, the engine will operate with 4 cylinders.
Last time I drove an American V8 with cylinder deactivation technology, I experienced the full power of all 8 cylinders when flooring the accelerator, while it automatically switched to 4 cylinders in city traffic jams, visibly slowing down the fuel gauge drop. The principle involves using oil pressure to control the camshaft pushrods, keeping the intake and exhaust valves of some cylinders permanently closed, turning the pistons into empty air pumps without fuel injection. I noticed slight steering wheel vibrations, though the auto start-stop system makes more noticeable movements. This system suits drivers who frequently use highways, especially with current high fuel prices - it can bring the combined fuel consumption of large-displacement vehicles down to around 10L/100km, much more economical than hardcore off-roaders.