The Honda v-tec systems use an extra lobe on each cam, and have an
additional int. & exh. valve per cylinder, which gets activated at high rpm,
by a pin activating and locking the extra rocker arms together.
With the Nissan VCT, I am trying to work out exactly how it works myself. I
am trying to get Motec to control it, but am not sure exactly how the vct
works, and if it can just be stuffed around with. With the standard
computer, the ecu controls a solenoid valve controlling oil pressure to the
vct actuator, which as far as I know, in the low/mid rev range is turned on
advancing (increasing overlap) to the intake cam. From 5700rpm onwards, the
system is turned off, retarding the int. cam.
Regards
Greg
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of
[EMAIL PROTECTED]
Sent: Wednesday, 26 September 2001 2:06 PM
To: [EMAIL PROTECTED]
Subject: Re: Varable Cam Timing
The honda V-tec system has two lobe profiles ground side by side for each
valve. The whole camshaft slides forward or backward using engine oil
pressure to change from the mild to wild profile.
Nick
>
> From: "Williams, Ritchie (Vertex
Hamilton)"<[EMAIL PROTECTED]>
> Subject: Re: Varable Cam Timing
> Date: 26/09/2001 15:39:37
> To: [EMAIL PROTECTED]
>
> James
>
> The most common way I've seen is a chain/belt tensioner on the tight side
of the chain/belt
> activated by a hydraulic cylinder.
>
> As the cylinder pushes the tensioner the tight side of the chain/belt
effectively becomes shorter
> therefore advancing the cam timing. As the revs go up the more the cam
advances. This is all
> controlled by the engine computer.
>
> There are other variations on this theme.
>
> --
> Ritchie Williams
> Manager - Design Technology
> Vertex Pacific Limited
> 696 Te Rapa Rd
> Private Bag HN3044
> Hamilton
> New Zealand
> ph 64 7 8493 999
> fax 64 7 8498 764
> e-mail [EMAIL PROTECTED]
>
>
>
>
>
>
> James Cox wrote:
>
> > Ok I know this is a little off topic, but does anyone know how VCT
physicaly
> > works? Yes I know about the benifits of advanced timeing at higher
revs, I
> > was just curious how they do this mechanicly in the new engines.
> >
> > James Cox
> >
> > _________________________________________________________________
> > Get your FREE download of MSN Explorer at
http://explorer.msn.com/intl.asp
> >
>
>
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