CVT auto stop switch?

[ac7ss]

I read the clutch/brake switch thread in here. I was wondering if anyone had done a similar thing with a CVT?

The brake pedal has 2 switches, taillight and Autostop. My theory is that if you place an override switch on the Autostop switch (NC when pedal up, so it would have to be a NC momentary in series with the switch) it should give you autostop as if the brakes were applied.

Has anyone done this with a CVT? Is it that simple or do you have to wire the taillight switch as well? Does it give you regen?

The answers to these and more.... (Please reply, I want experience of others before I poke holes in my wiring and cowling.)

[joecvt]

Originally Posted by ac7ss

The brake pedal has 2 switches, taillight and Autostop. My theory is that if you place an override switch on the Autostop switch (NC when pedal up, so it would have to be a NC momentary in series with the switch) it should give you autostop as if the brakes were applied.

Has anyone done this with a CVT? Is it that simple or do you have to wire the taillight switch as well? Does it give you regen?

You can tap into the brake pedal switch but when you activate your switch, AutoStop will not happen until your vehicle speed goes to 4MPH or below. It is just like pressing lightly down on the brake pedal though.

The MT models can be forced into an Auto Stop (called FAS). This is really a forced eninge stall by the push of a button. The FAS mod cuts off the power to the fuel injectors so the engine stalls when you push the switch. The MT is able to restart under several conditions using the IMA including just pressing down on the gas pedal. The FAS seems to work well with MT owners.

However, there are problems trying to do a FAS mod on CVT Insights. Those problesm have to do with the CVT design and I will list a few issues:

1) The CVT normally AutoStops at speeds 4MPH or below. The reason is to place the belt / pulley in the proper ratio for low speed take off upon the next restart.

2) the engine to be running (rotating) in order to adjust to the proper ratio before going into an AutoStop.

3) The start clutch will only disengage around the 4MPH area.

If you tried a FAS mod at speeds say 10 MPH and above, the CVT has no way to change the belt position to the proper ratio of where you want to restart.

Many of the CVT functions use hydraulic pressure and with no engine running due to a FAS, the start clutch does not disengage properly and actually feels very abnormal.

I have tried some of this stuff earlier to see if FAS could actually work in a CVT but found that it would probably cause damage to the CVT under long term conditions.

So, what I decided to do next was to fool the computer into doing REAL AutoStops at low speed. As you may know, if you are stuck in traffic or the drive-thru, you can not get another AutoStop from an unmodified CVT Insight until you travel at least 8 MPH or more then you will go into AutoStop the next time you come to a stop. In stop and go traffic and the drive-thru, you normally can't get back up to the 8MPH set point before you have to stop again so you end up wasting gas the next time you come to a stop.

I created what is called the Low Speed Auto Stop (LSAS) controller that will fool the computer into thinking that have exceeded the 8MPH set point only for a split second (even if you only really have been going 3MPH) and when you press your foot on the brake again and come to a stop, the CVT Insight will automatically go into another AutoStop. This cycle continues without the need to press any buttons....It is all automatic so you don't have to think about it.

I posted a lot of information about the LSAS when it was first being constructed here:

Automatic Low Speed Auto Stop

I have sold some of these to forum users in the past and I have been recently asked how much does it cost to build some more. The original price was $250 because I spent tons of time manually creating solder traces on a very small PCB and took several days to complete. Within the past month or so, I have discovered how to use presensitized PCBs and now I am able to create a circuit board with etched traces in much less time. What used to take about 4 days can be now done in about one long day once I have all of the parts.

I can now offer these LSAS controllers pre-built and tested for $85 plus shipping for CVT Insight forum members (I'm not ignoring MT onwers but you guys already have a method to do the same thing and purchasing my controller would be redundant). For anyone interested, I will create a post in the Buy / Sell section to purchase one of these controllers.

JoeCVT = Just your average CVT owner

[ac7ss]

JoeCVT: I understand the concept with your board, I was tempted to do it myself.

What I want to do is make the computer think the brakes are applied without actually touching the brakes. Allowing auto stop to occur when it is supposed to and full regen braking up to that point. Yes, it is practically the same thing as lightly touching the brakes, but easier not to engage the hydraulic system.

The trouble is finding a dpdt on-(on) switch. Or making a relay circuit to allow a single switch to do all of the work. I want to do as little to the car as possible.

So, to re-iterate the question, Does the brake switch have to be closed before opening the auto-stop switch?

[joecvt]

Originally Posted by ac7ss

What I want to do is make the computer think the brakes are applied without actually touching the brakes. Allowing auto stop to occur when it is supposed to and full regen braking up to that point. Yes, it is practically the same thing as lightly touching the brakes, but easier not to engage the hydraulic system.

The trouble is finding a dpdt on-(on) switch. Or making a relay circuit to allow a single switch to do all of the work. I want to do as little to the car as possible.

So, to re-iterate the question, Does the brake switch have to be closed before opening the auto-stop switch?

Sorry, I looked at your question in two different ways....I wasn't sure if you wanted to:

1) Just to tap into the brake pedal switch and do Auto Stop as normal without using any friction braking until you press down on the brake further.

2) Go into AutoStop at anytime just by using a switch tapped into the brake pedal switch.

I tried to say that number 1 (first paragraph of reply) is basically the same as lightly touching the brake pedal.

I further went on to say that it would still only work at speeds below 5MPH and perhaps went way too deep in the following paragraphs thinking that you wanted to modify in order to do number 2.

Now that I know what you really want, I will try to make my answer more on topic

Maybe it is just a difference in switch adjustments from car to car but when I first slow down to go into AutoStop, I lightly touch the brakes to get max regen then as the car slows down to about 4MPH the start clutch disengages and I feel the car at that time needs more brake pedal pressure to stop the car even at that slow speed. This tells me that the hydraulic brakes either are not even applied at that point or not enough to make the car stop. To even make that point even bigger, in a normal auto braking system, it does not take much hydraulic pressure to stop a very light car going only 4MPH compared to what it takes going 50MPH.

If you feel that you are using too much hydraulic brakes, I don't know how you can prove it but it may just be the "sensation" of the combination of regen and the CVT still engaged that gives you the feeling that your hydraulic brakes are activated too much that makes you want to do this mod. If you keep the brake pedal pressure the same during the AutoStop and after you get to 4MPH, does your car roll even further from 4MPH to 0MPH? Mine does by alot so that means there is not enough hydraulic pressure to stop until I press down further on the pedal.

Here is one thing that you can try before tapping into wires and mounting a remote switch.....Those two switches on the brake pedal (yes MT owners - the CVT has two switches) can be height adjusted. So why don't you adjust each switch one by one (remember how many turns so you can go back to default position if you had to) and go out for a test drive. Once you get it so that the slightest pressure works for you, I think that you will like that instead of having to keep a switch pushed in while stopping.

To try and answer your other question, are both brake pedal switches involved to achieve an AutoStop? I don't know for sure but I think so. Here is why....I have another CVT mod that relaxes the CVT ratio a bit unless under heavy engine load or about 20 seconds after touching the brake pedal. One of the wires in the mod hooks up to the brake lights so it uses the brake pedal switch that controls the brake lights. On the circuit, I have a diode inline to the brake switch but it went defective. When that occurred, I could not get into AutoStop until I fixed that circuit. For that reason, I think both switches are used.

An easy way to tell for sure is to disconnect the brake light connector from the switch but leave the other switch in tact. Go down a road in your neighborhood (with no other cars around - because you don't have brake lights) and try an AutoStop with all of the conditions that a normal AutoStop would occur. That should answer your question for sure.

Hope that helps,

JoeCVT = Just your average CVT owner

[ac7ss]

Perhaps you are right, If I just adjust my free-play to the maximum of 5mm so that I can activate both switches without applying any braking. (I believe that the pedal is tighter than that now.)

I wear big boots. Kinda makes it difficult to judge the movement of the pedal sometimes.

[vmirjamali]

What type of mpg gain are you looking at for one of these joecvt, any idea? Definately an interesting idea.

[joecvt]

Originally Posted by vmirjamali

What type of mpg gain are you looking at for one of these joecvt, any idea? Definately an interesting idea.

It varies based on the amount of stop-n-go in bumper to bumper traffic conditions you experience.....Some people have to go through that stuff every day so their fuel savings will be high.

An engine idling for no real good reason is just wasting gas. It really doesn't improve mileage while you are driving (car moving), it makes it so you don't lose any of that MPG if you have to a lot of stop-n-go in bumper to bumper traffic.

So I can't give just one MPG number since people in NYC will likely save a lot more fuel compared to someone that lives in low population areas.

And it does this all automatically so no buttons to push.

Hope that helps answer your question,

JoeCVT = Just your average CVT owner

[RobertSmalls]

Originally Posted by ac7ss

I wear big boots. Kinda makes it difficult to judge the movement of the pedal sometimes.

I have a relay that emits an audible click every time the brake lights come on. Now I know exactly how hard to press the pedal. I'd recommend running a little dash-mounted LED to provide instant feedback when the brake lights come on.

[ac7ss]

I have been trying to figure out a way to hook up a light to the AS switch, but it is NC when the pedal is up. I will try to just use the brake switch and see how that works for me.