Honda Car Forum


 

Go Back   Honda Car Forum - Accord Parts Civic Tuning Acura Racing > Discussion > Honda Technical

Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 11 Apr 2010, 01:16 pm
Member
 
Join Date: Aug 2007
Posts: 35
Default What tells Vtec to Engages Vtec?

What tells vtec to engage, i know how it works and shit but what tells that cam to lock?
Reply With Quote
  #2 (permalink)  
Old 11 Apr 2010, 01:31 pm
Jin Jin is offline
Member
 
Join Date: Jun 2008
Posts: 68
Default

The ecu















Electronic Control Unit
Reply With Quote
  #3 (permalink)  
Old 11 Apr 2010, 01:46 pm
Senior Member
 
Join Date: Aug 2007
Posts: 481
Default

In earlier versions of VTEC, the engine's computer (ECU, PCM, whatever you want to call it), reads a signal from a sensor or multiple sensors, either tach sending unit or oil pressure (or both) to determine at what time to engage the second set of rocker arms and the higher lift camshaft lobes. Once it hits the right levels, it will lock the rockers and thus engage the additional, larger camshaft lobe. If memory serves me, it's actually oil pressure that locks the rockers together, but I could be mistaken on that.































Edit: I am actually not mistaken according to the website I found.































Here's the description of how it mechanically works:"Picture, if you will, one cylinder of a DOHC, 4-valve per cylinder engine. There are 4 cam lobes, each directly operating a valve (two intake, two exhaust). The VTEC system has two more cam lobes, in between each pair of the other respective sets. These two can then be our high-rpm lobes, while the other four are the low-rpm lobes.































The low-rpm lobes in this case then actuate the valves through a set of rocker arms, so that the mechanical connection can be broken if desired. The third, high-rpm lobe also has it's own follower, but it is in a freewheeling state, flopping around and not contributing anything. As our engine accelerates through it's rev range, it passes through the power peak of the low-rpm lobes. Then, at the engine speed and throttle position programmed into the computer's memory map a signal is sent which electronically opens a spool valve, which then directs oil pressure to a mechanical sliding pin. This pin locks the rocker arms actuating the valves to the follower on the high-rpm cam lobe. As this grind is steeper and higher then the other four cams it will supersede them. In a few milliseconds you have completely altered the valve timing and the engine's power band begins anew. "































www.nsxprime.com
Reply With Quote
  #4 (permalink)  
Old 11 Apr 2010, 02:01 pm
Junior Member
 
Join Date: Apr 2010
Posts: 2
Default

there's a little leprechaun that lives under the came cover, when you hear the duuuh sound that's him talking to the cam.... da diddily de.. potato's
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Do all the 5th gen. preludes come with vtec or dohc vtec? or sohc vtec? Ruben K Honda Technical 4 04 Nov 2007 08:00 am
Do all the 5th gen. preludes come with vtec or dohc vtec? or sohc vtec? Ruben K Honda Technical 0 04 Nov 2007 07:50 am
Do all the 5th gen. preludes come with vtec or dohc vtec? or sohc vtec? Ruben K Honda Technical 0 04 Nov 2007 07:50 am
How can I tell when the VTEC engages when I'm driving my 99 Honda Civic EX? worthy0042 Honda Technical 7 30 Oct 2007 06:39 pm
How can you tell when vtec engages on a b16a2? co3_aziza2005 Honda Technical 5 28 Oct 2007 04:54 pm


All times are GMT -5. The time now is 02:05 am.


Attribution:
Honda News | Autoblog
Powered by Yahoo Answers




Powered by vBulletin®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
LinkBacks Enabled by vBSEO 3.6.0 PL2 © 2011, Crawlability, Inc.
HondaCarForum.com is not affiliated with Honda Motor Company in any way. Honda Motor Company does not sponsor, support, or endorse HondaCarForum.com in any way. Copyright/trademark/sales mark infringements are not intended or implied.