VIDEO: Dry but fascinating explanation of variable valve timing - Hyundai Genesis Forum
Cylinder Head and Valvetrain This section is for top end engine parts (for example porting heads, upgrading valvetrains, etc).

LinkBack Thread Tools Display Modes
post #1 of 1 Old 08-09-2009, 03:51 PM Thread Starter
Old Timer
Join Date: Jan 2009
Posts: 3,187
RSS-Feeds is on a distinguished road
(Thread Starter)
Lightbulb VIDEO: Dry but fascinating explanation of variable valve timing

Filed under: Technology, Videos

Honda K20Z3 featuring i-VTEC - click above image to watch the video

The powers that be are pleased you enjoyed the differential video so much. So much so that here's another. Dilemma: you want oodles of torque at low speeds because you must overcome one of Newton's pesky laws about bodies at rest tending to stay at rest. However, once you're at speed you'd like to substitute power for torque. Back in the old days, there wasn't a good solution. In fact, the best you could do was take the big block approach and provide more torque and horserpower than a car's suspension, brakes and driver could handle. There was also the European solution: diesels for torque, fancy-pants DOHC gas engines for power. Or the Japanese method: neither. But what if you wanted both?

Enter variable valve timing. Simply put, without variable valve timing, the valves open and close in a fixed pattern and there's no way to increase or decrease the amount of valve overlap (the percentage of time both intake and exhaust valves are open at once). Depending on the lumpiness of the cam, some engines are good for low-speed torque, some for high-rpm power (and/or valve float). With variable valve timing, the rate and duration of the camshaft striking the rocker arms can be altered, varying the valve overlap and resulting in both better low range torque and better high rpm power. Plus, you get the advantage of increased mileage throughout the power band (if you like). Nifty -- but how's it work? If you'd like to know, make the jump and watch the video.

Continue reading VIDEO: Dry but fascinating explanation of variable valve timing

VIDEO: Dry but fascinating explanation of variable valve timing originally appeared on Autoblog on Sun, 09 Aug 2009 18:23:00 EST. Please see our terms for use of feeds.

Permalink | Email this | Comments

RSS-Feeds is offline  

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome