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| Keywords: cruise control cruisecontrol project 365 project365 retrofit s40 indoor I really love the Volvo that Mike sorted out for me, but one thing that I miss is cruise control. In Britain it's actually pretty rare that you can use it in anger, but when you need it, you need it. I know that I'll soon be driving down seven miles of speed camerad 50mph roadworks for which cruise is absolutely perfect. This means it's time for a retrofit! Most cruise control systems are pretty simple. You've got a set of switches inside the car and you've got a vacuum operated servo in the engine bay that physically pulls the throttle cable. These both connect to the control module. The control module reads the speed pulse from the engine control unit and pulls the throttle cable to maintain the same speed. You've also got a safety cut out switch on the brake. That's pretty much it. What's interesting is that some cars are fitted with electronic throttles, also known as 'drive by wire'. This is partly to remove the throttle cable, but also to remap the throttle curve. This means that you can do things like apply 60% of throttle when you only press the pedal 30% which makes the car feel more torquey and powerful than it really is. A useful by product of this is that the throttle actuator and control mechanism is already coded into the ECU and it becomes trivial to fit cruise control. If you're really lucky, all you need to do is fit the cruise switch and the brake switch and you've got cruise control. Most manufacturers install the harnesses for them and just don't connect them. I've done that, and having spent about twenty quid on ebay now have a brake switch and a cruise control on my indicator stalk. As you can see from the pic, the little cruise light is lit on the dashboard, so we're almost there. Sadly, there's a missing link. I need a firmware update for the engine control unit to enable the cruise system. Blessedly, I know someone who works at a dealership. ;) I'll keep you posted. :) I really love the Volvo that Mike sorted out for me, but one thing that I miss is cruise control. In Britain it's actually pretty rare that you can use it in anger, but when you need it, you need it. I know that I'll soon be driving down seven miles of speed camerad 50mph roadworks for which cruise is absolutely perfect. This means it's time for a retrofit! Most cruise control systems are pretty simple. You've got a set of switches inside the car and you've got a vacuum operated servo in the engine bay that physically pulls the throttle cable. These both connect to the control module. The control module reads the speed pulse from the engine control unit and pulls the throttle cable to maintain the same speed. You've also got a safety cut out switch on the brake. That's pretty much it. What's interesting is that some cars are fitted with electronic throttles, also known as 'drive by wire'. This is partly to remove the throttle cable, but also to remap the throttle curve. This means that you can do things like apply 60% of throttle when you only press the pedal 30% which makes the car feel more torquey and powerful than it really is. A useful by product of this is that the throttle actuator and control mechanism is already coded into the ECU and it becomes trivial to fit cruise control. If you're really lucky, all you need to do is fit the cruise switch and the brake switch and you've got cruise control. Most manufacturers install the harnesses for them and just don't connect them. I've done that, and having spent about twenty quid on ebay now have a brake switch and a cruise control on my indicator stalk. As you can see from the pic, the little cruise light is lit on the dashboard, so we're almost there. Sadly, there's a missing link. I need a firmware update for the engine control unit to enable the cruise system. Blessedly, I know someone who works at a dealership. ;) I'll keep you posted. :) | ||||
