pettaw, the full throttle (kickdown) switch breaks the mass circuit to point 6 of the tacho relay. it is in series with the Lowgearholdswitch and highpressurebrakeswitch
all 3 switches are Normally Closed types. if any of these is opened, 'overdrive' side is deactivated, 'low gear' side activated.
the diagram Mac's designed is really good, its just that the centre area should always be marked with 'regulated vacuum' colour.
CVT tester
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antiekeradio
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antiekeradio
- Posts: 697
- Joined: 04 Jan 2004 10:53 am
- Location: roosendaal - netherlands
- Contact:
Yes of course Wouter - that 'central chamber' would be subject to regulated vacuum all the time the engine is running. (thanks for that).
Also (I think), I really should have shown the non return valve as closed when the outer chambers are evacuated - as the vacuum equalises on either side of the valve the spring would shut it.
To get a full view I need to portray 'full engine vacuum', 'regulated vacuum', 'destroyed vacuum (air admitted)' and probably 'reduced vacuum (part throttle cruise)' as well. When I have time I'll have a play around and write up an appendix to my CVT article (I want to expand it into the unit rebuilding side of things at some stage anyway).
I guess the design thoughts re. reduced full throttle vacuum was that the LRH switch was more likely to be used descending a slope on closed/low throttle (when vacuum is high) than holding low gear when accellerating. I think it is less an issue in 'kick down' as the full throttle switch will simply release the vacuum held (by the non return valve) by opening the o/d solenoid. The lack of high engine vacuum to apply via the brake solenoid will prevent the CVT changing down too far at higher speeds.
The 'theory fog' begins to clear! If you have any more thoughts do please shout.
Mac.
Also (I think), I really should have shown the non return valve as closed when the outer chambers are evacuated - as the vacuum equalises on either side of the valve the spring would shut it.
To get a full view I need to portray 'full engine vacuum', 'regulated vacuum', 'destroyed vacuum (air admitted)' and probably 'reduced vacuum (part throttle cruise)' as well. When I have time I'll have a play around and write up an appendix to my CVT article (I want to expand it into the unit rebuilding side of things at some stage anyway).
I guess the design thoughts re. reduced full throttle vacuum was that the LRH switch was more likely to be used descending a slope on closed/low throttle (when vacuum is high) than holding low gear when accellerating. I think it is less an issue in 'kick down' as the full throttle switch will simply release the vacuum held (by the non return valve) by opening the o/d solenoid. The lack of high engine vacuum to apply via the brake solenoid will prevent the CVT changing down too far at higher speeds.
The 'theory fog' begins to clear! If you have any more thoughts do please shout.
Mac.
