I guess it has been my understanding that the ICE is NEVER used to fully top-off the hybrid battery charge so some "space" will always be left available to take advantage of the potential of free energy via regenerative braking. I have also always thought that there should be a mode switch available that I could use to tell the system that those opportunities will be few and far between, on a 160 freeway trip, for instance.

 

[For simplification, "Full" will mean the maximum charge the system will accept, and "Empty" means the lowest level the system will allow before instituting recharge]

No, you misunderstood. The example was highway driving which always requires ICE. If you accelerate to pass, the system will provide a boost from the battery thereby slightly reducing your battery from "full". Assuming you stay at highway speeds and the ICE is still running, the system will recharge the battery to "full" immediately. In other words, IF THE ICE IS RUNNING and your battery is less than "Full" it will immediately recharge.

If the ICE is OFF and you are in EV mode ICE will not come on to recharge until you reach "Empty". If you deplete the battery below this level ICE will come on to recharge at least minimally unless your driving dictates ICE stay on anyway.

 

That may be something a scanguage owner can answer. If you are driving at highway speeds and therefore a "full battery" what is the numerical SOC displayed? If you then brake or shift to L and coast what happens? Does the SOC increase or does the system spin the engine to alleviate the extra charge? If SOC increases that would imply that the system "leaves room" for some extra juice. If it spins the ICE faster it would imply that "full" means full.

 

That is correct Willard, the generator stops charging just under the battery limit. This is to allow braking and regen without a run-up of the ICE. I remember when Ray and Rich first told me about "L" gear (which there is no real gear), they were getting that run-up. Never had a run-up and thought it was only a problem with the AWD. Sure enough it started happening to my FWD from using "L" for charging the battery.

On the highway, the FEH fills the battery and charging is reduced to just a few seconds every so often to fill the 12V battery. The 12V runs the accessories and is constantly slowly draining. Of course, the generator will also assist the traction motor for above WOT and recharge the battery.

While you are in "D" there is also a little regen at a steady state speed. If you drive in "L", there is more regen at a steady state speed. This regen is not shown on the energy display.

GaryG

 

GaryG wrote: "the generator stops charging just under the battery limit"

The ACTUAL usable HV Battery SOC is 40% to 60%.
Engine/Generator charging stops at 55% to allow 5% of "room" for regeneration.

GaryG wrote: "The 12V runs the accessories and is constantly slowly draining."

This is not really the case. The HV battery acts as an alternator would in a traditional car. Once a tradtional car is started, the 12v battery can be removed and the alternator will provide all power for lights and accesories. Same is true in the Ford Escape Hybrid. The HV battery pack powers all accessories when the key is in the run position, as long as the HV battery pack is above 40%. The 12v battery only powers lights and accessories when the key is off, or in rare cases the HV battery is 40% or lower. ( also keeps your clock and other "memory" set )

GaryG wrote: "Most of the drop in MPG is from ICE WOT (wide open throttle) and not recharging the battery. Remember, as soon as you see the assist needle move, your at WOT. In the FEH Atkinson ICE, WOT (100% engine load) can be as low as 2,000rpm. The SG measures engine load and has been a great tool for increasing MPG."

The above is not true. The term WOT is not understood, or the term is being mis-used by GaryG. The more open your throttle position, the more efficient your engine is running. When I spoke person to person with the Ford Hybrid engineering team last year, I told them that I was getting fantastic fuel economy at Denver's altitude. I presumed due to lower wind resistance at altitude. While somewhat true, two engineers told me that due to less oxygen, my throttle position was always open wider than those at sea level, even at idle. Also, I would hit WOT more often, and under more conditions than a driver at sea level.
Confirming to me that I would be getting the most power per gallon at WOT. Gettting more power from the engine, meant less battery assist required.

Also, the statement that you are at WOT any time you see the "assist" needle move is ridiculous. It could be that way sometimes, but this is a complex system with computers that make 100's of adjustments per second. Battery assist can happen ANY time the computer calculates it to be a benefit to user demand. It is my understanding that the "engine load" feature of the ScanGauge does not work correctly in the Ford Escape Hybrid and this may have lead to some false impressions.

WaltPA wrote: "I run that last part of my commute just on the batteries. So far, I have made it into the garage with the batteries pretty well drained, but there was no attempt to re-charge them. Of course, when I leave again, the Mariner is cold and the ICE needs to run [anyway]. At that time, the batteries do get re-charged."

This is generally recognized as a good practice, and many Hybrid drivers do this. But did you know that during the first 30 seconds of your next cold re-start the FEH uses purely electric propulsion under 40 MPH? If you are in a position to start the car and move immediately next time, leaving a little battery charge can be a good thing. Most pollution comes from a cold engine. Ford engineers programmed the FEH not to use gasoline for acceleration during the first 30 seconds unless you floor it and demand tremendous acceleration. I now leave a little green in the battery when I park at night, and I fasten my seat belt, make adjustments, look for traffic, etc BEFORE turning the key. Then I turn the key and get to 25-35 MPH ASAP in those first 30 seconds. This saves a thimble of gas each time, but adds up over a year!

-John

 

In that first 30 seconds, when you try to get to 25-30mph ASAP, how do you know if you're not using ICE, since it is on? Is it because you are accelerating while the ICE RPM stay constant? If the Ford engineers say so, then it is true, but how about your own acceleration? Is your acceleration slow enought NOT to use ICE to accelerate? How do you gauge how fast you can accelerate in that first 30 sec without using ICE?

Seems to me that if this is true/possible, then the Ford engineer should have set the FEH up for all acceleration by E only from 0mph in ALL conditions, and not just in the first 25-30 seconds. I would imagine this would be desireable since everyone is trying to stay in EV, but have to accelerate really really slow to do so up to 32mph.

 

That's a really narrow band of usable battery. Where did you get that piece of data?

Seems like you can potentially double your battery potential without adding weight by just adjusting the computer to keep SOC at 30% to 70%. I would imagine Ford has data on the NiMH for SOC tradeoffs vs battery life. It would be great of they would give you an option to choose, say 20%-80%, 30%-70%, or 40%-60% on battery SOC and the tradeoff for battery life and let the owner decide. I think we would have a wealth of real world data on from users and optimize FE vs battery life.

Of course we would have to sign a wavier on that 100k miles battery life warantee. There are those who would consider that.

 

John wrote: “The HV battery pack powers all accessories when the key is in the run position, as long as the HV battery pack is above 40%. The 12v battery only powers lights and accessories when the key is off, or in rare cases the HV battery is 40% or lower. ( also keeps your clock and other "memory" set ).”

The 12V battery stores electricity, it is voltage stabilizer for the elec. system and temporary power when the elec. loads exceed the DC/DC converter output current. DC current is supplied to the 12V battery through the low voltage battery cables.

John wrote: “The above is not true. The term WOT is not understood, or the term is being mis-used by GaryG. The more open your throttle position, the more efficient your engine is running.”

Wow, don’t know what to make of this statement John. I referred to WOT at 100% engine load. That is the point at which the ICE is producing its max torque at that RPM. The PCM and Scangauge see this, and if you are demanding more torque with accelerator position, you get motor assist as shown in that stock gauge. You are confused about max torque and max efficiency I think. The air fuel mixture at 14.7 to 1 or lower will give you the best fuel efficiency with regard to throttle position.

If I thought for one moment that my SG was incorrect as you say, I would return it. During warm-up, the computer does use the electric motors more for torque as Randykato has stated. The SG verified this when I check engine load. If the battery SoC is good, the RPM’s will not increase sometimes as you accelerate.

Occ, if your RPM is increasing, you are using some ICE for torque. Also, the battery protection system should not be changed IMO.

GaryG

 

You guys DO understand that WOT stands for Wide Open Throttle right?
That would be when the tps, (throttle position sensor) shows that the pedal is mashed....

MM

 

Mark, in the FEH, when you are at WOT and asking for more torque depending on accelerator position, you get elec. motor assist. A mashed accelerator will provide motor assist after WOT (100% load). The PCM determines throttle valve position for air fuel mixture. There is no carb throttle any more.

GaryG