Feature request: Cruise control

[357supermagnum]

As some cars has a GPPS sensor (Gas Pedal Position Sensor), and a VVS sensor, a trottle body with a stepper motor and a TPS. It should be possible to make a board that reads the GPPS sensor, and the VVS sensor along with optional GPS speed information from the I/O board. A simple momentary closed switch connected to a input wire can be used to set and activate the cruise control. A prosessor then commands a stepper motor to add more air/trottle if the vechile speed falls under a set hysteresis window. And back up on the trottle if the vehicle speed gets over the same hysteresis window.

Depressing the brake,gas pedal or clutch pedal will disable the system so the driver can change the speed without resistance from the system. The brake light switch can be used to disable the system.

Inputs needed:
+12V (from ignition)
Engine ground

TPS:
TPS power ( if dual TPS sensors)
TPS signal
TPS ground (possible ground loop problems, could be fixed with a separate TPS)

GPPS:
GPPS+5V
GPPS signal
GPPS ground

VVS:
VVS power
VVS signal
VVS ground

Output:
Stepper motor controll wires:
CoilendA1
CoilcenterA
CoilendA2
CoilendB1
CoilcenterB
CoilendB2

I/O:
CAN-Low (CAN-)
GND (Ground)
CAN-High (CAN+)
CAN V+ (Power)
USB port

[muythaibxr]

Since MS is for "offroad use only" and I can't think of a reason why you'd want cruise control on a track or similar, we won't be implementing cruise control.

Not to mention that we don't have the resources necessary to do what I would call a "proper" test of cruise control to make sure it doesn't do anything bad in any situation.

Ken

[T3Bunny]

Good answer Ken, cause none of us would ever run these on the road....

If you have an older car like mine, there is a very large grey area. As long as you don't live in Cali. My '77 is suspicious (if an inspector is paying attention) as it blows MUCH cleaner than any car its age should. It blows the requirements for its year right out of the water. It actually blows cleaner without a cat, than the requirements for an early VW Rabbit WITH a cat.

Unfortunately Cali does not care if it is cleaner, they want OE working perfectly. And they actually have flags set that certain cars will almost automatically fail. If you own any of the CIS Injected cars, your basically screwed. In my opinion, I think any car that can pass its requirements for that year or better, should be left alone. but then there are people out there like myself, that can in minutes retune a car to blow clean specifically for that test. And well mine does not run 14.7 across all the ranges like an OE Rabbit with "WORKING" Lambda feedback would.

But I digress, what your asking for (cruise control) would be not only a crap load of man-hours in design, coding, and testing, it is cost prohibitive and a serious liability issue. Last time I looked (couple years ago) there were several aftermarket cruise control systems available. Well tested, verified, and in the $100 target zone. They are likely not intended for offroad use though, just sayin!

Heck, lets go take a look as now I am thinking that would be a stupidly cool add on to my car... Huh, guess it was more than "just a few" years ago. Rosta makes an "electronic" setup that is universal. It is $200 and then you also need to choose a switch setup for it. Those seem to range $30-75. I see a couple others out there too that are cheaper, and vacuum operated.

[T3Bunny]

Ah found one! http://www.carisini.com/products/Audiov ... JDGJ6.html

[UnaClocker]

That Rostra unit is worth every penny. I used to install them, the vacuum ones are pretty much non-tunable. It either works, or you yank it off and sell the customer the better Rostra that they should have bought in the first place.. heh..
Oh, and the stupid fly-by-wire cars.. Drill a hole in the floor, run the cable up under the pedal and pull the pedal itself with the Rostra cruise control.. haha. Did that countless times.You can find the Rostra for $150 if you dig.. And it can be wired to factory speed sensors, and factory cruise knobs (common in American cars, at least, so you can find them at the JY..)

[T3Bunny]

Hummm... I could not find much info (perhaps I did not look close enough though). So if I am understanding correctly, the Rostra basically uses a cable "actuator" to proportionally pull on either the pedal, or the TB arm?

Frak, I wish I had realized how simple and clean that was then! I had Factory CC in my old Rabbit cabriolet, but it didn't work. And transplanting the vacuum actuator to my then new project, would have been a bit ugly and unsightly. So I dumped a VERY rare CC stalk along, with everything else. I bet I could still score another stalk though...

I already get some confused looks when I hit the alarm remote on my '77, and the doors lock. But hey, I also have the headlight switch on the floor, attached to HID headlights!

Why NOT add CC to the odd mix???

[UnaClocker]

Yes, it's got some sort of electric motor that pulls a cable that you hook to the throttle plate (comes with a couple adapters in the kit).
I know the feeling with the alarm and power locks, my commuter car is an '84 Diesel Rabbit.. I did the same thing, power locks and an alarm.. Big booming sound system in it too.. ;)

[andi-at]

Hello,

I want to pick that topic up again, i found a good offroad-usecase for it...

I want to build up a generator, ms would be perfect for that. Only problem - i have to keep the generator at the same RPM at every load, otherwhise the frequency would drop.
So the easiest way doing that would be hooking up the speed sensor to the generator output, setting the speed to the right frequency and dont care any more.

I think it would also be possible to build up a CAN-Module which reads the sensor data and sets the throttle valve. But thats too much coding for me i think /:

Or is there a easy way to do that with ms? Setting the IDLE-Speed to the desired RPM wont do the trick on full load, will it?

thanks a lot!
Andi

[Matt Cramer]

For a generator, the closed loop idle control code probably would work. Completely inappropriate for cruise control, though, so don't think this is a wink and a nudge endorsement of what would be a very bad idea.

[andi-at]

Yeah i thought about that too. But will it work up to 100% load, is it able to control idle over an electronic throttle valve?
That would work for the first stage of my project, but when its finishd it should have a automatic transmission to keep up economy at low (default) loads but providing seamlessly the full power potential of the engine if its needed.
Mabe thats not exact of what a cruise control is built for, but its the closest that fit my needs what i can think about.

You support ships, aircrafts, dirtbikes, jetski, etc. Mabe it would be a good feature (and new usecase) for the microsquirt? Who can say he built up a fully electronic controlled, fuel-economy, alternative-fuel-feeded 50kW Generator out of his broken car? Sounds good to me!

best regards,
andi

[Healey3000]

A little out of the box thinking here (which can mean wild/crazy/silly):

MS has the means to control a fuel pump via PWM for a returnless system. Can that be used?

Using an RPM sensor, low-pass filter it to create a DC value. This would therefore be a voltage proportional to RPM (higher the RPM , higher the voltage). Feed that into MS to simulate a fuel pressure sensor. Take the PWM output from MS that would normally go to the fuel pump but connect it to an idle control valve. Feed the IAC airflow to the intake. You may need a few IAC valves in parallel. Alternatively, feed the PWM to a vacuum control solenoid to pull on a throttle cable, like a cruise control actuator does.

As RPM goes up, "FPR" voltage goes up. MS thinks that the fuel pressure is increasing so it reduces the PWM duty cycle to the IAC. Airflow drops and engine RPM drops. Loop closed.

If there's a way to dynamically alter the setpoint then it would work for any RPM on-demand. You could put a pot on the FPR signal and turn it to fake the feedback value, forcing a higher RPM setpoint.

However, we are talking about a generator, right?

[andi-at]

Man that sound really "wild" but the more i think the better it gets! The setpoint can be done wih a simple voltage-divider wich sets the dc-value.
But i think it wouldnt be very much work to build up a microcontroller wich do the RPM-PWM conversion. Then a simple control algorighmus can be used and the original ecu can be used for the first testing.

So i have to say - thanks a lot man!
greetings from austria

[Emre]

Greetings,

I'm living in Istanbul, Turkey and driving 2000 model 1.8 Turbo New Beetle. I'm planning to buy MS3-Pro. However, I'm also using cruise control for long drives (about 600-700 kilometers) every 3 months. That's why I'm really curious about if I will still use cruise control or not after the installation of MS3-Pro?

P.S: In Turkey, you can drive almost every kind of cars for on roads even setup is for off road