HVB Fastest Charging Rate From ICE

[ptjones]

I monitor my SOC(state of charge of Hybrid Battery)with ScanGaugeII and I noticed that on my last trip to AZ the HVB charges the fastest at two bars on empower on the Smart Gauge.  This actually makes sense when you think about it.  When you are going uphills you don't want to use much power charging the HVB.

Likewise the ICE isn't as efficient at low power levels.  Since the beginning I have noticed the ICE wants to run at Two Bars. :) 

 

Paul 

[fbov]

Interesting observation.

 

Mine is that engine speed for a 2-bar burn can be anywhere between about 1500 and 2300RPM, depending on load and SOC. Managing RPM is the key.

 

When first driving the C-Max, I spent a month developing a hybrid driving technique based on input here, before recording standard route data. My understanding was to "accelerate as fast as you can while still charging." As long as you saw a ^ above the battery, you were good.

 

As I thought about it, I realized in my case, this was a bad thing. I wasn't giving the battery enough charge time, so EV was limited. I started looking more at RPM than Empower bars, because I could hear the engine speed  wasn't following the Empower display.

 

The next season, I tried to keep RPM below 2000, corresponding to a 1.5-2 bar burn in Empower, depending on SOC. I accelerated more slowly, but for a longer time, so average speed didn't change (still a 15 mile, 30 minute trip).

- mileage went up 12-15% (more benefit in warmer temps)

- fraction EV went up from 67% to 71%

 

Now... 2000 RPM many not get you up to highway speeds, or up steep hills. I'm driving 35-45 speed limits on generally flat land, so no one should take any of this as an absolute. Just think about charging time when selecting ICE run modes, and you'll gain EV miles.

 

HAve fun,

Frank

[stevedebi]

Interesting observation.

 

Mine is that engine speed for a 2-bar burn can be anywhere between about 1500 and 2300RPM, depending on load and SOC. Managing RPM is the key.

 

When first driving the C-Max, I spent a month developing a hybrid driving technique based on input here, before recording standard route data. My understanding was to "accelerate as fast as you can while still charging." As long as you saw a ^ above the battery, you were good.

 

As I thought about it, I realized in my case, this was a bad thing. I wasn't giving the battery enough charge time, so EV was limited. I started looking more at RPM than Empower bars, because I could hear the engine speed  wasn't following the Empower display.

 

The next season, I tried to keep RPM below 2000, corresponding to a 1.5-2 bar burn in Empower, depending on SOC. I accelerated more slowly, but for a longer time, so average speed didn't change (still a 15 mile, 30 minute trip).

- mileage went up 12-15% (more benefit in warmer temps)

- fraction EV went up from 67% to 71%

 

Now... 2000 RPM many not get you up to highway speeds, or up steep hills. I'm driving 35-45 speed limits on generally flat land, so no one should take any of this as an absolute. Just think about charging time when selecting ICE run modes, and you'll gain EV miles.

 

HAve fun,

Frank

I found the same thing on my Escape Hybrid. A gentler accelleration resulted in better MPG. That is different from some of my ICE vehicles, which worked better by getting up to speed quickly.

[fbov]

Indeed it is.

 

In the early 80's, you started to see car makers looking seriously at mileage in their designs. BMW developed the "eta" engine, limited to 4500 RPM by all the internal efficiency mods (reduce frictional losses), but with all the torque of a much smaller, conventional engine. They included an early MPG meter, and it was tied to the throttle; poor mileage if you didn't run wide-open - when accelerating - so you got to top gear sooner.

 

I did the same experiment in my cars. With fuel injection, best mileage came when combining WOT acceleration with very short shifts, so you get to 5th gear as soon as possible, without running the engine over 3000 RPM (it's gutless range).  Use the fewest engine revolutions to get up to speed, and you use less fuel doing so, is the idea.

 

Of course, we're not driving a car, but rather a power station, run by a stationary motor operating in an optimized manner for the level of load imposed. I like it.

 

Frank

[ptjones]

Another way to look at it is the less time the ICE is running, the less gas you use and the better your MPG's.  Using P&G I would accelerate about 2 Bars to predetermine  speed, then glide to desired speed and then use EV.  I only used ICE 28% of the time when I got my 68.3mpg tank.  :)

 

Paul

Edited December 11, 2015 by ptjones

[ScubaDadMiami]

Interesting observation.

 

Mine is that engine speed for a 2-bar burn can be anywhere between about 1500 and 2300RPM, depending on load and SOC. Managing RPM is the key.

 

When first driving the C-Max, I spent a month developing a hybrid driving technique based on input here, before recording standard route data. My understanding was to "accelerate as fast as you can while still charging." As long as you saw a ^ above the battery, you were good.

 

As I thought about it, I realized in my case, this was a bad thing. I wasn't giving the battery enough charge time, so EV was limited. I started looking more at RPM than Empower bars, because I could hear the engine speed  wasn't following the Empower display.

 

The next season, I tried to keep RPM below 2000, corresponding to a 1.5-2 bar burn in Empower, depending on SOC. I accelerated more slowly, but for a longer time, so average speed didn't change (still a 15 mile, 30 minute trip).

- mileage went up 12-15% (more benefit in warmer temps)

- fraction EV went up from 67% to 71%

 

Now... 2000 RPM many not get you up to highway speeds, or up steep hills. I'm driving 35-45 speed limits on generally flat land, so no one should take any of this as an absolute. Just think about charging time when selecting ICE run modes, and you'll gain EV miles.

 

HAve fun,

Frank

 

 

Another way to look at it is the less time the ICE is running, the less gas you use and the better your MPG's.  Using P&G I would accelerate about 2 Bars to predetermine  speed, then glide to desired speed and then use EV.  I only used ICE 28% of the time when I got my 68.3mpg tank.  :)

 

Paul

 I have found that both examples are what I follow.

 

When doing charge ups, I try to stay at about 2,000 RPM or lower. I started doing this after Dave of Durham, I think, mentioned it. I found that it corresponds to just over a one bar representation in Empower, something like 1.1 or 1.2.

 

When doing pulse and glide, I've found that, if you are going to activate ICE, the amount of fuel used for a shorter burn at a higher RPM is probably less than doing a slightly longer burn at a lower RPM. This usually translates to about two bars, and when I have gone even higher than this (which is what Jus-A-CMAX mentioned, some time ago), it hasn't hurt my fuel economy, though I don't have much experience in this realm.

[stevedebi]

 I have found that both examples are what I follow.

 

When doing charge ups, I try to stay at about 2,000 RPM or lower. I started doing this after Dave of Durham, I think, mentioned it. I found that it corresponds to just over a one bar representation in Empower, something like 1.1 or 1.2.

 

When doing pulse and glide, I've found that, if you are going to activate ICE, the amount of fuel used for a shorter burn at a higher RPM is probably less than doing a slightly longer burn at a lower RPM. This usually translates to about two bars, and when I have gone even higher than this (which is what Jus-A-CMAX mentioned, some time ago), it hasn't hurt my fuel economy, though I don't have much experience in this realm.

FWIW, when using the cruise control to accelerate (in EV or hybrid mode with ICE), the car sets the acceleration to about 1.75 on the Empower guage. You can use the CC to accelerate after you get going from a stop, once you get up to a certain speed (15 or 20 MPH comes to mind).

 

I mention this number because Ford presumably programmed it for a reason.

[ptjones]

FWIW, when using the cruise control to accelerate (in EV or hybrid mode with ICE), the car sets the acceleration to about 1.75 on the Empower guage. You can use the CC to accelerate after you get going from a stop, once you get up to a certain speed (15 or 20 MPH comes to mind).

 

I mention this number because Ford presumably programmed it for a reason.

I will have to try that out. Thanks :)

 

Paul