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Discussion Starter #1
Thought I'd post here about the progress I've been making on the app I started late last week. I find myself looking down at the Volt's dash more than I would like when I'm driving, especially in CS mode, to try and drive more efficiently. The data points I look for most frequently are whether or not the engine is running, and the power consumption (as the engine starts if it goes about ~15 kW, and I like to coast as long as possible with the engine off).

This app will work best when the phone is mounted on the windshield, closer to the driver's field of vision when they are looking at the road. Here's a prototype screenshot (simulated values):



I'm very close to having it working. It connects to an ELM-based Bluetooth OBDII adapter, just like Torque. The only issue right now is that the CAN bus on my Volt is occasionally reporting "CAN ERROR" and I need to send initialization codes again when that happens, and I'm too tired to do any more testing (it only happens when I'm actually driving, of course :confused:).

The left bar is the battery bar. Normally it displays roughly the same value as the one on the Volt dash, but once the app detects the car is in "CS" mode (battery drops below a certain point), it stretches the bar to show the current charge level inside the "CS" window of charge.

The right is the same as the leftmost gauge on the Volt's dash in Enhanced mode (total power into or out of the battery). The green line is the estimated "engine start" point in CS mode, which I still need to tune a bit (it's hard to tell what the ramp is based on certain speeds, but I know that above 25-30 MPH, the threshold is a constant 15 kW). If the yellow bar goes above the green, the engine will start (or should, at least) if the car's in Charge Sustain or Hold mode. The background of the app changes from green to blue and the "EV" text goes away whenever the engine is on.

Sadly, I don't have all the PIDs I need to make this work exactly as I want. I can't get the exact "engine on" threshold, nor can I tell if the car is truly in CS or Hold mode. I also wanted to have it indicate when the friction brakes kick in during braking, but I can't find a PID for that either.

I plan on putting this on the Play store when I finish it, probably for a buck or two.
 

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Discussion Starter #3
I don't see any simulated values.
The screenshot was before I hooked it up to OBD (using fake values for the gauges), but in theory they're not unrealistic values. I'm currently having issues getting the app to remain connected to the ECU, but I almost have it nailed down. It works for several minutes at a time before it has to be restarted in the current state.
 

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Discussion Starter #4
In an ideal world, it would be great to find the PIDs that the dashboard uses to determine whether "EV Range" or "Fuel Range" is lit up, which I could then use to show or hide the green line on the right. Also, the bar on the right of the app currently shows the same as the bar on the left on the Volt's dashboard, whereas I would prefer if it showed a graphical representation of the "Power" measurement at the top of the dash. If you're accelerating and the engine is charging the battery, the bar will go down into the green but the "Power" at the top of the Volt's dash will be a positive number.
 

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The right is the same as the leftmost gauge on the Volt's dash in Enhanced mode (total power into or out of the battery). The green line is the estimated "engine start" point in CS mode, which I still need to tune a bit (it's hard to tell what the ramp is based on certain speeds, but I know that above 25-30 MPH, the threshold is a constant 15 kW). If the yellow bar goes above the green, the engine will start (or should, at least) if the car's in Charge Sustain or Hold mode. The background of the app changes from green to blue and the "EV" text goes away whenever the engine is on.
By writing that the "EV" text goes away and the background changes from green to blue whenever the engine is on, you seem to be suggesting that "EV" will be displayed and the background will return from blue to green whenever the engine is off. Is "EV" displayed even if you are driving on battery power that was put there via braking regen while you were driving with the ICE running, or while driving downhill with a fully depleted battery?
 

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Discussion Starter #6 (Edited)
By writing that the "EV" text goes away and the background changes from green to blue whenever the engine is on, you seem to be suggesting that "EV" will be displayed and the background will return from blue to green whenever the engine is off. Is "EV" displayed even if you are driving on battery power that was put there via braking regen while you were driving with the ICE running, or while driving downhill with a fully depleted battery?
Yes, I'm using the background and "EV" text as an instantaneous display, not an overall mode display. I got the app working reliably enough to use on my way home from work today, and the green "engine on" threshold combined with the color-changing background whenever the engine turns on or off helped me achieve 54 average MPG after depleting my battery, whereas I have previously been averaging 45 on the same trip. I need to tune the threshold curve a bit but it was definitely helpful to me as an efficiency aid without really causing any driving distraction (glancing to my phone at the left edge of the windshield is much easier than glancing through the steering wheel down at the dash)

The specific styling/wording of the "EV" indicator was inspired by the Lincoln MKZ Hybrid my dad owns, which has a similar display built into its dash (see here). I got upwards of 40 MPG in that car by being mindful of the engine running and using "EV" mode as much as possible.
 

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helped me achieve 54 average MPG after depleting my battery, whereas I have previously been averaging 45 on the same trip.
How long were you in CS mode -- i.e. how many miles @ 54 MPG?

I found in my Gen 1 (jury still out on Gen 2), that you could use some variation of "tricks" (usually heavy regen + low speed) to keep the ICE off in CS mode for a while but eventually the ICE will force run because you dipped into the battery buffer too much, negating much of the gas savings. However, this was a great technique if you wanted to save some gas only a few miles from a plug.

Not sure if Gen 2 is the same way.
 

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Discussion Starter #8
How long were you in CS mode -- i.e. how many miles @ 54 MPG?

I found in my Gen 1 (jury still out on Gen 2), that you could use some variation of "tricks" (usually heavy regen + low speed) to keep the ICE off in CS mode for a while but eventually the ICE will force run because you dipped into the battery buffer too much, negating much of the gas savings. However, this was a great technique if you wanted to save some gas only a few miles from a plug.

Not sure if Gen 2 is the same way.
I think it was about 10-15 miles. One of my tricks is to get up to a little bit higher speed than I would coast at and grab the regen paddle for a half second or so. It tricks the car into thinking you're slowing way down and it shuts the engine off even if it's trying to charge the battery up, so you can dip further into the CS charge window. Then when you brake, it recovers plenty of it back.
 
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