John, I made no mention of a water temperature or catalyst temperature sensor, what are you talking about?

Everything I've read about the FEH/MMH stated one of the requirements for EV mode was that the catalytic converter must be heated for EV. The PCM uses the front and rear sensors to calculate the CAT temp. These are heated oxygen sensors, not temperature sensors.

The light-off point I was refering too, is the point at which conversion efficiency exceeds 50%. Most converter temps are between 475F and 575F for the chemical reaction to be changed into mostly harmless products. My suggestion was that the lights-off point had to be reached as one conditions for EV mode.

It is my understanding also that the Keep Alive Memory (KAM) stores these HO2S reading if you shut off the engine before lights-off, and will resume at that point if the engine is restarted in a short time. This is why you can go EV after a short trip during a return if all other conditions for EV are met.

Since you brought up the fact that the FEH does not have a water temp sensor, here is what I think is the case.

The engine coolant temperature (ECT) information on the instrument cluster does come from the same ECT sensor used by the PCM for all its internal calculations. The cylinder head temperature (CHT) sensor sends the PCM a signal indicating cylinder head temp by resistance as the coolant temp increases. This could mean the CHT gives both the ECT information to the PCM. Section 303-14C-1 of the workshop manual (Electronic Engine Controls - Escape Hybrid) refers you to 303-14A - 12 for a nice diagram of the sensor and the location.

GaryG

 

Kermit... the "jump start" button helps boost the voltage of the HV battery by WARMING it. This has been discussed many times, in many places. ( searching for "official" Ford documentation of this, but I think GaryG has also seen this in print... )

Ah... here is it from Helms Workshop Manual, CD-ROM 2004 edition:
"NORMAL OPERATION:
When the jump start button is pressed, the jump start control module within the high voltage traction battery uses the low voltage battery during an 8 minute process to heat and [therefore] step up the low voltage [in the HV pack] in an effort to charge the high voltage battery to the point where it may start the engine and operate the motor generator within the eCVT"

Every battery, from a button cell watch battery, to deep cycle marine batteries have higher voltage/current output at warmer temps. ( Take a "dead" cell phone while you are out skiing and put it under your armpit for a few minutes to bring it to body temperature, and it will work again for a substantial number of minutes.) I have NOT seen schematic information that there is any "step up" voltage charger ( 12v to 330v )... only step down ( 330v to 12v ). While the term "charge" or "jump start" is commonly used... this is simply lay person jargon for the button in the driver footwell. The warmer temperature allows more battery output. I think it was clear, that while I was speaking "technically",.... 'TECHNICALLY' every FEH on the road DOES have a HV battery warmer.

Not my intent to embarass, but you kind of backed me up on this. I agree with you that a cold battery will not readily accept a charge. Thus proving that a battery WARMER will help "jump start" your car more than anything.

And a brief reply to Gary... yes, one programming parameter is the catalyist must be "warm" to allow EV mode. But since this is not measured, ( the O2 sensors measure O2, not temp. ) and is only calculated from the CHT sensor, keeping this sensor warmer by any means possible will allow more EV use. Which is what I already stated!

 

On page 8 of this document http://www.motorcraftservice.com/vdi...DSM500_HEV.pdf
it refers to catalyst temp as a condition for EV mode. It does not state how the temperature is determined, that was in the workshop manual. One thing I came across in other manuals was the catalyst needed to be at lights off temp (~600F) in order to go closed loop. Today I found that I got to closed loop (by the Scangauge) just under a mile after a cold start today. It took another half mile to go EV. The coolant temp was at ~140F after a mile and the outside temp was about 75F here at the time. When I was able to go EV, the coolant temp was at ~155F.

One other point I came across that you snowbirds might be interested in was the heater pump. It appears most people who want to go EV ASAP after a cold start may want to consider leaving the heater pump off till you can go EV. The heater pump will circulate coolant and increase the time to heat the engine.

The pump is commanded ON when the following conditions are met:

1. The key is in ON/START position.

2. The engine coolant temperture is above a min. threshold 32F nominal.

3. The inferred ambient temp is below a calibrated value 90F nominal.

4. The engine speed is below a calibrated threshold (nominal 4,000rpm) including engine off.

5. The climate control mode switch is in any position other than off.

The pump is off when the climate control mode is set to OFF.
Page 1-63 '05 PCM/ED.


GaryG

 

In the 2006 version of that document, it mentions a few times about "inferred catalyst temperature", but doesn't go into a lot of detail as to how the temperature is actually determined.

 

It was 18 deg last night. Suddenly, this now interests me more.

 

I have photos of the three Ford items needed to install the engine block heater. No I have not installed this item--yet.

 

At the Ford Hybrid "Fuel Economy Experience" we had back in '05, I specificially asked my engineer about how the car would deal with cold climates and whether I'd ever need to worry about the hybrid battery array starting the car due to extreme cold.

The short answer is that we should never need to worry that the electric battery will not be able to start the car unless the battery is actually defective. Cold temperature is not a problem.

As he explained it... a gasoline engine needs to be cranked at about 15 rpms (give or take) in order to start. Much less than that and car wont start in cold temps. This is why people end up having to phone the auto club for a jump-start on bitterly cold days (not that the gasoline wont combust... but rather that the battery is so cold that it can't supply enough power to crank the starter fast enough to trigger the combustion.)

The FEH has a starter that can easily crank the engine to life at 1500 rpms (vastly faster than any normal non-hybrid car starter and 100 times faster than required for combustion to occur). This is needed because the engine has to be started while the vehicle is already at some moderate speed to create a smooth transition from electric power to gasoline power. Now think about that carefully... that is TWO ORDERS OF MAGNITUDE beyond what the engine needs to start, or, stated differently, if the battery can only must enough power to crank the starter at a mere 1% of it's normal speed, the car will STILL START!

Ford has done testing on this and tried to find extreme conditions to ensure that the car could start. The engineer explained to me that in bitterly cold weather, I *might* have to settle for merely 700-800 rpms of cranking power (still WELL beyond what is needed to make a combustion engine start). His opinion was that it's pretty inconceivable that even the most extreme locations on the planet could be cold enough to prevent the car from starting due to a cold battery. My understanding is that jump-start button is really just there not for the cold alone, but rather in the event that the battery was allowed to run rather low on real power *and* it's also very cold. A normal healthy hybrid battery array should never have a problem due to cold temperature.

As for engine block heaters -- those are for bitterly cold climates (very few places in the continental US qualify -- think northern Minnesota, North Dakota, etc.). The rest of us don't have winter temperatures that would ever require one.

 

Lots of information in the last post and something the experienced posters can digest quicker than I can at this time. Any ways, I understand it as there are two starters in the FEH, one that operates with the key and the other by the Ford Motor Company desgined software. I did not purchase this item for just for ease of starting purposes. I purchased this engine block heater in an attempt to decrease the run time of the ICE before the vehicle can go into EV during the colder months of the year. I been known to spend most winter weekends skiing and figure I could use my portable power pack jump starter with an inverter on my Escape Hybrid for this purpose when I am not at home.
I hope this helps someone else.

 

Billy! Thanks for the posts and the photos too!

There is just one way to start the car.
The 12v battery "turns on" the 330v battery when you turn the key.
( your key is only in contact with 12v for obvious reasons )
If your 12v battery is ever dead, or missing for that matter, a 12v laptop or camcorder battery could be enough to "turn on" the big battery and start the car. The 12v battery never cranks the engine.

When the 330v circuit is completed, the 330v battery energizes the smaller 40kw motor that in turn, spins the engine to 1000 RPM or slightly more.
The engine does not get fuel or spark until it is moving over 1000 RPM.
Then the engine fires away, and off you are on your way.

The post about the battery getting cold and "only spinning the engine 800 RPM" is a false assumption. The engine must always be moving at over 1000 RPM to get spark. ( Notice idle is never less than 1000 RPM either. ) So starting the car at 800 RPM is never, ever, a possibility.

HOWEVER... the assumption that the battery pack is powerful enough by several times over, to start in the majority of cold climates is true. Since the battery and 40kw motor have the ability to spin the engine at 5000 RPM if necessary, there is about 5 times the minimum power required to start the car. Not quite 100x as implied below, but the right idea was stated.

-John

 

The engineer who explained to me what would happen in a cold climate was one of Ford's engineers on the project and did cold-weather testing personally.

I'm wondering why you are saying it will refuse to provide spark unless it can get 1000 rpm. Though it's generally not a good idea to assume the way things work in a typical car also apply to the hybrid, in a typical engine idle speed and the speed required to start combustion have nothing to do with each other (lots of engines start at low RPM and then spin up to some idle speed higher than what they started at.) Certainly a combustion reaction _can_ be started at 15 rpm, but your reply seems to indicate that it would be prevented in the hybrid -- contradicting what the Ford hybrid engineer told me.