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CR3 (2022-현재) · 1.5T AWD

2026. 8. 10. 작업

증상

I see that almost all of Honda's cars have an "i-VTEC" logo at the back. I googled it and came to know that it has something to do with different cam profiles. Can someone explain? A diagram or animation would be helpful. And why does Honda do it?

처리 내용

In addition to Zaid's answer. VTEC - V ariable Valve T iming and Lift E lectronic C ontrol) In essence, it selects between two different cam profiles depending on the RPM. Here's an animation - This is how a cam controls poppet valves. Read about cam profile here For volumetric efficiency we want the intake stroke to fill the cylinder with the max - air-fuel. I'l jump to the need for having a different cam profile at higher RPM's Valve Timing Intake - Valve isn't open long enough for the air (or air-fuel mix) to completely fill up the cylinder under the given pressure gradient. We could help this situation by using a different cam profile which allows the cam to be open for longer. This means the intake valve is open even after the piston reaches the bottom of the intake stroke. Air at this velocity has sufficient momentum to continue to push and compress into the cylinder even as the piston is moving up for the compression stroke. Exhaust - we could do something clever here as well. I