How to build a start/stop switch?

[viktor_k]

I'm wanting to build a start/stop switch, hopefully intergrated into the shift knob for my mazda, anyone done that? My biggest dilemma is how to properly kill the motor with a single tap. So far here's what I'm thinking:

1. Single push button wired up to a microcontroller board like arduino (have one laying around)
2. Have a vaccuum switch be one of the inputs
3. 12V relay for starting the motor.

Basically, to start the car, press the button, controller checks the vacuum switch position, if engine is off then it proceeds to start the motor (would be nice if i didn't have to hold the button though). To kill the engine you press the same button and the controller then sees that the engine is running and instead will kill the ignition until the vacuum switch shows that it is shut off completely.

Is there a cleaner way to do this?

 

[BRIAN_MP5T]

This will require the key to be put in regardless, why not have the "Start" Function be part of the start button, and to shut the motor and lock the steering, remove the key as per normal.

 

[viktor_k]

This will require the key to be put in regardless, why not have the "Start" Function be part of the start button, and to shut the motor and lock the steering, remove the key as per normal.

Yea, I'm ok with that, i'm not after being "cool" here, i do pulse & glide driving most of the time and my wife gets irritated from the click...click with the ignition key all the time, and it does get irritating often especially when you don't quiet kill the car and it comes back.

 

[cdnballer]

Doesn't stopping/starting your engine all the time wear it out faster? I can see the starter motor wearing out faster too since the Mazda isn't designed for this function. I figured any fuel savings you achieve is completely offset by higher maintenance costs.

 

[BRIAN_MP5T]

Yea, I'm ok with that, i'm not after being "cool" here, i do pulse & glide driving most of the time and my wife gets irritated from the click...click with the ignition key all the time, and it does get irritating often especially when you don't quiet kill the car and it comes back.

No offense, but that is the dumbest thing I have ever heard.

What you are saying is that you shut the engine off when it is moving to try to save money on gas?
and you have selected an antique design platform with a huge air cross section, that is horrible on gas to attempt to do this with?


No Motor. NoPower Steering.
No Motor.No Power Brakes.

Mechanical wear and Tear.
Not to mention that every time you start the car there is a massive load applied to the alternator to recover the electrical charge in the battery.

Not only is it irritating to your wife, but it will never result in any cost savings.
It is reckless and dangerous to other people on the road.

I want no part of this

 

[Silentnoise713]

No offense, but that is the dumbest thing I have ever heard.

What you are saying is that you shut the engine off when it is moving to try to save money on gas?
and you have selected an antique design platform with a huge air cross section, that is horrible on gas to attempt to do this with?


No Motor. NoPower Steering.
No Motor.No Power Brakes.

Mechanical wear and Tear.
Not to mention that every time you start the car there is a massive load applied to the alternator to recover the electrical charge in the battery.

Not only is it irritating to your wife, but it will never result in any cost savings.
It is reckless and dangerous to other people on the road.

I want no part of this

I do not practice nor do I endorse this technique but if used appropriately by someone knowledgeable and an alert driver, pulse and glide is one of the many hypermiling techniques that’s been around for a while. It's efficient b/c you are essentially moving, say 60 MPH, without consuming any gas when you are gliding –infinite miles per gallon until your speed become unsafe to others. Works best when there’s an ever so slight decline in the road. There will be some minor additional mechanical wear and tear but if the OP is planning on dumping the car later down the road, it’s a none factor. No PS is not an issue once you are at speed (I prefer it). No PB can be tricky unless the OP has some husky legs but not much different than coasting in neutral for manual drivers in that add time is need for evasive measures. I would think the OP knows the section of the road and road conditions well to do this.


I will say I’d HATE to be behind a hypermiler

 

[viktor_k]

No offense, but that is the dumbest thing I have ever heard.

What you are saying is that you shut the engine off when it is moving to try to save money on gas?
and you have selected an antique design platform with a huge air cross section, that is horrible on gas to attempt to do this with?


No Motor. NoPower Steering.
No Motor.No Power Brakes.

Mechanical wear and Tear.
Not to mention that every time you start the car there is a massive load applied to the alternator to recover the electrical charge in the battery.

Not only is it irritating to your wife, but it will never result in any cost savings.
It is reckless and dangerous to other people on the road.

I want no part of this

With that logic though, mazdaspeed3 is also reckless and dangerous especially when chipped and boost limit removed from first and second gear, but people still do it and are praised to do it. I've been doing pulse and glide for years and so have thousands of others. I don't recommend it to anyone that isn't ONE WITH THE CAR, if you know what I mean. But to clear up some of your misconceptions:

1. It doesn't wear out the alternator any more than when you crank the stereo up or when you install any kind of woofer, I'm not talking about running the car for hours with the motor dead.
2. You loose power steering, but that's only bad if you weren't expecting that to happen. Also, i believe that's hackable in MZ5, i just haven't gotten around it, doesn't it use electric power steering? either way, my previous cars were much more difficult to turn than MZ5 with the motor killed, you just get used to it.
3. You have full brakes for at least 4-5 pumps, in the entire time I've done this, I maybe had 1 or 2 instances when I needed to pump more than 3 times when the motor is coasting, not a problem though, just pop it into gear and you're back in business.
4. It makes you a more engaged driver, thus a safer driver, you're constantly paying attention to your surroundings, drivers around you, etc...
5. There's no wear on the starter since most of the time you're bump starting it, rarely will I be sitting at a stop light and needing to restart with a starter, in those instances its still justified since it was likely a long wait. If i see a stop light turning yellow, I slow down way early and will coast to it in a way that still allows me to restart.




But here's some number to digest from my Nissan Versa MT for example:

Doing 80% 2-mile city trips (car is in warm-up stage mostly) I would get 26mpg. Doing pulse & glide with the exact same driving cycle I can get almost 40mpg. The 26mpg is also being very frugal in driving, but without killing the motor. With mz5 I'm certain I can be 30+, but could probably be even close to 35, we'll see.

So, it does pay off, and it doesn't wear out any part of the car any more than normal.

There are companies out there working on stop/start hybrid technology that could be retrofitted into any ICE car. All you need to do is replace the alternator with a more powerful motor with some smart electronics. You also need to have an electric PS and electric Brakes, both are possible. This is simply a manual way of doing this.

 

[viktor_k]

Yea, I rarely do this on freeways, i'd die being behind a person that's doing it at freeway speeds, I'd rather be behind an SUV in those cases. I do it mostly around town and yes on roads I'm familiar with. I wouldn't be doing it if I thought it was damaging the car, and if it wasn't worth it. I also doubt you would know that I'm doing this if you were following me. In some cases I do slow down early, but I'm also saving you gas

Other than the clicking from the key, you also wouldn't know I'm doing this if you were the passenger, its a very smooth process (once you're "ONE WITH THE CAR" )

 

[Davicho]

I'm sorry but I agree with BRIAN. It is the dumbest idea and a unsafe one at that...no matter how much or well "YOU'RE ONE WITH THE CAR" as you put it. If you want that feature then get a damn Prius V.

 

[viktor_k]

I'm sorry but I agree with BRIAN. It is the dumbest idea and a unsafe one at that...no matter how much or well "YOU'RE ONE WITH THE CAR" as you put it. If you want that feature then get a damn Prius V.

I'm curious, how's it unsafe? in what situation would it be safer running the motor? Sounds like an episode for mythbusters.

 

[DKaz]

I did this in an older car. Instead of starting the car using the starter, I would put the car in gear and let the clutch out to restart the engine. I wouldn't risk it in a newer car however. I P&G'ed engine off once in each of my Mazdas, but restarted using the starter. In my 07 Mazda 5 however, power steering didn't come back on. I didn't risk it again after that. In my 12 Mazda 3, power steering does come back on, but I get good enough gas mileage without having to resort to these extreme hypermiling techniques. I still do pulse & glide when traffic conditions permit, but with the engine on.

I found that the old 2.3 was much more responsive to these mild hypermiling techniques, aka I saw a lot more benefit. Not so much with the Skyactiv 2.0. In my Mazda 5, I would often get into the 30-35MPG range on 30 mile jaunts in/out of the suburbs.

 

[Silentnoise713]

For people who haven’t done it or understand the process, it would seem dangerous (even bazar) but I agree with you in that with an experienced driver behind that wheel this is no more or less safer (leaning towards safer) than an average driver barreling down the road in cruise control. The biggest difference is that you are more alert. What you do loose is the engaging driving experience but I understand not everyone is into that and I assume this is your kind of driving excitement. Folks tend to think white knuckle driving is the only thing exciting/rewarding.

I’m guessing you are a hard core hypermiler? What else do you do and what's your MPG on the Mz5?!


EDIT: Moving to electronics.

 

[viktor_k]

For people who haven’t done it or understand the process, it would seem dangerous (even bazar) but I agree with you in that with an experienced driver behind that wheel this is no more or less safer (leaning towards safer) than an average driver barreling down the road in cruise control. The biggest difference is that you are more alert. What you do loose is the engaging driving experience but I understand not everyone is into that and I assume this is your kind of driving excitement. Folks tend to think white knuckle driving is the only thing exciting/rewarding.

I’m guessing you are a hard core hypermiler? What else do you do and what's your MPG on the Mz5?!


EDIT: Moving to electronics.

I'm relatively new to MZ5, i did drive it across the US, but with crazy weather did not try to hypermile it much, it was enough of a rush flying 70mph through patches of black ice and truckers on my behind, but with the last tank I've just started to bond closer with the car and looks like it'll be around 30mpg before I'm done with it, but I do let it rip once in a while . It was much easier in the versa since the car seemed to curse at me whenever i tried to push it more than normal, but with mazda it seems to ask for it...

I don't do crazy hypermiling, at freeways I'll draft as much as possible, city driving I'll limit the time I'm stopped at lights and do more coasting with engine off. I suspect that I'll be able to get up to 35mpg if I try hard enough.

My drive across the US averaged around 27mpg, with nebraska and most wyoming totally killing the mpg down to 19, crazy cross/head wind. Best tank was 30mpg, but most of the speeds were above 70mph and quiet a bit of 85mph.

I used to own a 2003.5 MSP, had it tuned and dynoed at around 230whp, then i spent years in eco boxes producing less than 100hp, so the mazda with its zoom-zoom handling is making it difficult keeping that hypermiling mindset

 

[BRIAN_MP5T]

Drafting is also known as "Tailgating", and at 85 MPH with the kids in the trunk, I can see how saving $0.73 in gas dring across the continent would seem worth it. Good on you for doing your part.

Driving at 85MPH on ice tailgating an eighteen wheeler with headwind simply quantifies my expectations of you.

Whenever you need a paint job for the hood, or have to pay the deductible because you smashed into the back of a truck, or worse hurt your family, remember to post up in this thread how awesome you are.

 

[viktor_k]

Drafting is also known as "Tailgating", and at 85 MPH with the kids in the trunk, I can see how saving $0.73 in gas dring across the continent would seem worth it. Good on you for doing your part.

Driving at 85MPH on ice tailgating an eighteen wheeler with headwind simply quantifies my expectations of you.

Whenever you need a paint job for the hood, or have to pay the deductible because you smashed into the back of a truck, or worse hurt your family, remember to post up in this thread how awesome you are.

Brian, i'm not quiet as stupid as you make me out to be, no family was in my car and if you read my post I said i did not do much hypermiling due to weather. Semi trucks were tailgating me through most of the nasty weather because clearly weather conditions do not effect their driving style.

I also mentioned that I draft behind suvs and I don't kiss the bumper either, you don't need to be very close to a semi-truck to be drafting, but i stay away anyway since the cost of the windshield is much more than a few gallons of gas.

I take it you're the safe driver around here, always following the suggested speed through the corners and always coming to a complete stop, right?

I'm not here to argue who's safe and who isnt, I simply asked if anyone has done a proper start/stop button for the older mazdas. I figure some kid has installed one for the "cool" factor at least.

 

[mazdadude]

Todays cars do not like being turned on and off while moving.

Try doing an emergancy avoidance swerve and brake with no power steering and brakes.

Also, do all of your safety systems like your traction, stability, and airbags still work while doing this?

Wouldn't it just be easier to reduce your airflow by putting a plank of wood in place of your airfilter with a couple holes drilled in it? VIOLA! You will be saving lots of fuel all of the time!

That being said, you can go to the miatanet forum and in the garage there, you will find the info on how to install the BRB Honda S2000 pushbutton into the Mazda Miata ignition system.

 

[viktor_k]

Todays cars do not like being turned on and off while moving.

Try doing an emergancy avoidance swerve and brake with no power steering and brakes.

Also, do all of your safety systems like your traction, stability, and airbags still work while doing this?

Wouldn't it just be easier to reduce your airflow by putting a plank of wood in place of your airfilter with a couple holes drilled in it? VIOLA! You will be saving lots of fuel all of the time!

That being said, you can go to the miatanet forum and in the garage there, you will find the info on how to install the BRB Honda S2000 pushbutton into the Mazda Miata ignition system.

Restricting airflow will make the motor run less efficient, since it has to work harder pulling the air in. I've see the start buttons everywhere but no stop button, that's the tricky part to me, it'd be nice to be able to kill the motor with just a quick tap and that gets more complicated. You can interrupt the injectors for example, but if you just do it momentarily it won't guarantee that the engine has died. I'm wondering if having a vacuum switch is the only way to be sure that the motor has stopped.

 

[flcruising]

I have no idea how the arduino works or what it can interact with, but I would think that a microcontroller that has output for actuating the 12v starter relay (the one at the main fuse block not the starter solenoid) and a PWM sensing input would be all that's necessary to perform what you describe. Key in the RUN position at all times and the PCM shouldn't care how the starter engages. The PWM input could be from an injector, cam or crank sensor. Just have to set a low threshold otherwise it may think that the cranking engine is a run condition.

 

[viktor_k]

I have no idea how the arduino works or what it can interact with, but I would think that a microcontroller that has output for actuating the 12v starter relay (the one at the main fuse block not the starter solenoid) and a PWM sensing input would be all that's necessary to perform what you describe. Key in the RUN position at all times and the PCM shouldn't care how the starter engages. The PWM input could be from an injector, cam or crank sensor. Just have to set a low threshold otherwise it may think that the cranking engine is a run condition.

how would you kill the motor though? If i kill the motor by interrupting the injectors, then I can't rely on PWM that drives it. Hmmm, cam or crank sensor could work, would have to check if the ecu is going to care if i tap off of the signals though. Are you sure that cam or crank is PWM?

 

[rodslinger]

I think what some are missing is that our vehicles already use ZERO gas while gliding. With your foot completely off the accelerator pedal when slowing down the fuel supply is cut. I don't mean reduced, fully cut. The fuel supply only returns when you either touch the gas pedal again or you slow enough that the engine does need to produce power to maintain idle or rev slightly for a downshift at speeds below about 30mph.

Shutting down the vehicle for a few seconds at a light may not offset extra fuel used during the short open loop rich operation for the few seconds after the restart. I see this on my wideband gauge and have datalogged it during some tuning. My 5 runs anywhere from 12:1 to 13:1 for about five seconds after startup even when warm. I also see it run very lean at idel and very low load decel. In the range of 15:1 to 16.5 You also have to factor in the extra load on the engine from the alternator having to constantly recharge the battery.

Our vans weren't designed to operate like a hybrid.