Reverse Fake Shift
#31
12-09-2008, 01:35 PM
Re: Reverse Fake Shift
The past several days I have been simply lifting my foot at the time the engine starts. I lose 0.1% SOC on average doing this.
Once in a while, I lose 0.2%, and once or twice I didn't register any loss.
But on average, a restart takes away 0.1% SOC,
That all I'm saying.
Keeping my foot on the pedal, and getting gentle acceleration during a restart makes my SOC drop by 0.4% to 0.8%.
Once in a while, I lose 0.2%, and once or twice I didn't register any loss.
But on average, a restart takes away 0.1% SOC,
That all I'm saying.
Keeping my foot on the pedal, and getting gentle acceleration during a restart makes my SOC drop by 0.4% to 0.8%.
You are saying that from a stop, if you start out gently (trying to stay in EV), then when the ICE comes on you lift the pedal and gently re-apply it, you will save SOC? That is worth a try...
#33
12-11-2008, 12:32 PM
Re: Reverse Fake Shift
Well, I can't generally do this - lifting my foot completely off the pedal makes the car slow enough that people behind me might be upset.
I don't think there is much "magic" about this technique, however. When you lift your foot off the pedal, the FEH immediately starts putting some small charge back into the battery. So I would expect the SOC to be higher. If you think about it, this is basically a (very) short-term P&G (except the engine is still on).
The area in which I could use some tips is what to do when the SOC is low. When I start off in the mornings, the FEH is running on batteries (TPS is generally 15 or so regardless of speed). Then when I hit the corner at about 1 mile from home, the engine begins to do the donkey work, and I see my assist meter go way left; the vehicle needs about 2000 rpm to accelerate the same as it does at 1500 with a full SOC. So far I haven't decided on the best technique in these circumstances.
I don't think there is much "magic" about this technique, however. When you lift your foot off the pedal, the FEH immediately starts putting some small charge back into the battery. So I would expect the SOC to be higher. If you think about it, this is basically a (very) short-term P&G (except the engine is still on).
The area in which I could use some tips is what to do when the SOC is low. When I start off in the mornings, the FEH is running on batteries (TPS is generally 15 or so regardless of speed). Then when I hit the corner at about 1 mile from home, the engine begins to do the donkey work, and I see my assist meter go way left; the vehicle needs about 2000 rpm to accelerate the same as it does at 1500 with a full SOC. So far I haven't decided on the best technique in these circumstances.
#34
12-11-2008, 03:27 PM
Re: Reverse Fake Shift
Well, I can't generally do this - lifting my foot completely off the pedal makes the car slow enough that people behind me might be upset.
I don't think there is much "magic" about this technique, however. When you lift your foot off the pedal, the FEH immediately starts putting some small charge back into the battery. So I would expect the SOC to be higher. If you think about it, this is basically a (very) short-term P&G (except the engine is still on).
The area in which I could use some tips is what to do when the SOC is low. When I start off in the mornings, the FEH is running on batteries (TPS is generally 15 or so regardless of speed). Then when I hit the corner at about 1 mile from home, the engine begins to do the donkey work, and I see my assist meter go way left; the vehicle needs about 2000 rpm to accelerate the same as it does at 1500 with a full SOC. So far I haven't decided on the best technique in these circumstances.
I don't think there is much "magic" about this technique, however. When you lift your foot off the pedal, the FEH immediately starts putting some small charge back into the battery. So I would expect the SOC to be higher. If you think about it, this is basically a (very) short-term P&G (except the engine is still on).
The area in which I could use some tips is what to do when the SOC is low. When I start off in the mornings, the FEH is running on batteries (TPS is generally 15 or so regardless of speed). Then when I hit the corner at about 1 mile from home, the engine begins to do the donkey work, and I see my assist meter go way left; the vehicle needs about 2000 rpm to accelerate the same as it does at 1500 with a full SOC. So far I haven't decided on the best technique in these circumstances.
In my '09 FEH I use the RFS for restarting the ICE prior to the ICE starting on it's own whenever I can. The RFS is a quick blip of the accelerator to start the ICE. The tap on the accelerator is just enough to start the engine and after the engine is fully started you can begin to accelerate again. This method after practice can eliminate a drop in SoC you normally get from a restart. Here is how I use the RFS:
1. Instead of accelerating in EV from a stoplight, I let Off the brake and begin to roll in the Creap Mode for about a second and then tap the accelerator for a restart of the engine. After the restart I accelerate with the ICE On till I reach a steady state speed I want to cruise at in EV. In the '09 that up to 40mph and you go EV just by letting off the gas pedal. I do this at the same time I set the cruise control in EV.
2. Any time I need to accelerate in EV, I let Off the accelerator and do the RFS (blip or tap of the accelerator) for a restart and accelerate as needed.
3. This is the tricky part where you let the SoC drop just before a restart. If you get a restart before your able to do the RFS, it's to late and your going to get a big loss in SoC just about every time. This is why the RFS is so important and proving to be effective. I'm getting very good at getting a high percentage of RFS before a start-up, but those few that get by me really cost my average MPG. For instance today my SoC got down to 40.1% and I had a restart before I could perform a RFS effectively. The SoC dropped to 39.0% even though my foot was off the gas pedal the entire time. If I had performed a RFS before the restart I would have saved between 39.0% to 40.1% SoC which takes a long time to recover with the engine running. Depending on how fast I'm going in EV, I shift to neutral to cancel cruise control and glide prior to doing a RFS. At 40mph in EV, I find that I should not let the SoC fall much below 41% before I shift to neutral for the glide. The SoC will continue to drop and I don't let it get down to 40.4% without shifting to "D" and doing the RFS for the start-up with no SoC loss. At 30mph in EV, I shift to neutral at ~40.7% SoC and again shift to "D" at 40.4% and do a RFS for a restart with no loss of SoC.
Today was a bad driving day with high winds and rain and my Nav MPG this morning was at 53.0MPG when I left the house with a cold start. Made lots of stops shopping and still manage to have a 53.0mpg Nav average when I got home. This new technique will most likely give me a 2mpg tank mpg increase over my last tank which was 48.815mpg pumped gas (E10). This technique I consider magic when you increase that much MPG on E10 with 48mpg averages without it.
GaryG
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