Helicopter
New Member
- Joined
- Aug 31, 2007
- Messages
- 100
- Reaction score
- 3
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- Location
- Sydney, NSW
- Members Ride
- 94 VR Calais V8
The cruise control has no idea about what the absolute speed of the vehicle is !
It simply processes the pulses from the speedo sender from the gearbox.
Inside the cruise control is a large LSI chip that controls a high power stepper motor. Obviously the LSI chip is programmed to ignore any pulses below a certain frequency, which in this case is pulses received below 40kmh......whatever rate they may happen to be.
So when you activate or set the cruise control, if the pulses are above the minimum threshold, the cruise control memorises that setting, then takes command of the throttle cable in order to maintain this pulse rate hence speed, known as closed loop control.
To get it to operate below the 40kmh factory set point, you need to find a way to fool the cruise control into thinking the received pulses are above the 'lower threshold set point'. This would mean intercepting the speedo signal going into the cruise control in some way and modifying the pulse rate, but still maintaining a linear relationship to the actual or real signal sent by the speedo sender in order to stay in the closed loop state.
Jaycar do make a speedo correction kit that could be modified to achieve this, but as already mention a few times by other members, having cruise control set at 40km or below is no point and could prove dangerous. Not to mention making a modification which [perhaps] could be against the law.
Good luck.
It simply processes the pulses from the speedo sender from the gearbox.
Inside the cruise control is a large LSI chip that controls a high power stepper motor. Obviously the LSI chip is programmed to ignore any pulses below a certain frequency, which in this case is pulses received below 40kmh......whatever rate they may happen to be.
So when you activate or set the cruise control, if the pulses are above the minimum threshold, the cruise control memorises that setting, then takes command of the throttle cable in order to maintain this pulse rate hence speed, known as closed loop control.
To get it to operate below the 40kmh factory set point, you need to find a way to fool the cruise control into thinking the received pulses are above the 'lower threshold set point'. This would mean intercepting the speedo signal going into the cruise control in some way and modifying the pulse rate, but still maintaining a linear relationship to the actual or real signal sent by the speedo sender in order to stay in the closed loop state.
Jaycar do make a speedo correction kit that could be modified to achieve this, but as already mention a few times by other members, having cruise control set at 40km or below is no point and could prove dangerous. Not to mention making a modification which [perhaps] could be against the law.
Good luck.
