Pulse (accelerate the most efficient way) and Glide (coast with the least amount of drag in "D" or "N") IMHO, is one of the best ways to save fuel. It is true for me in non hybrid cars also. If my battery is full, all the better for P&G in EV for incredible MPG averages.

The only time I use battery and electric motor boost, is to avoid a stoplight stop. A complete stop will result in more energy and fuel than a battery and electric motor boost to make a stoplight, and I can use "L" regen with the extra speed to replace battery SoC right away.

When you call for assist for a pulse or normal acceleration, you are not at the most efficient way for FE. Assist means your a 100% load of the ICE, and dumping the most fuel you can possibly dump. In addition, take a look at the Assist/Charge needle, you are dumping as much battery charge you call for. The RPM rises along with assist, and you continue to dump the max fuel you possibly can. Can any of you think of a better way to get the worst mileage? I can't! The only time this can help is to avoid a complete stop.

The term "Fake Shift" is my creation, so I think I know how it works and how to use it.

As Far as Highway driving at speeds of 60-75mph, you can get 45mpg out of the FWD FEH. You need to know about drafting and KAM when not drafting.

GaryG

 

Sorry Willard... you need to experiment more, or at least read more on this site and others. Conventional wisdom DOES NOT APPLY to hybrid driving.

For example, hybrids get the best gas mileage in hilly, even mountainous terrain.
Sounds counter-intuitive, but it is true. Proven in the field time and time agian by numerous drivers. Pulse ( with gas, or EV gas combo ) followed by glide ( in EV ) gives FANTASTIC results ( 60+ MPG ) in a 4,000 pound SUV, no matter the battery state of charge. Without P&G I'd be getting 35 MPG.

My 2WD Hybrid Escape gets 42 MPG continuously at 55 MPH, and 37-38 MPG at 65 MPH. ( then drops steeply above 65 MPH )
How do you justify saying Hybrids are worse that traditional cars over the Highway???????????

 

Gary, Thanks, I've read and re-read your post/threads on cleanmpg many times trying to pick everything up, but there's so much info.


One comment and one question.

comment: accelerating with 1800rpm for me is hard for two reasons, one, even slight hilly is hard and very slow to get up to speed. Two, everybody is hustle-bustle around here and they'll drive you over you with hummers and navigators if I dont keep up with traffic (and I have a feeling they give hybrid a bad rep - bad car no power - we know it's not true, but they dont).

question: concerning your draft and KAM technique, how long do you have to draft before your KAM gets "filled" or keep the best FE before you stop drafting?

Thanks again Gary.

 

That has become my experience too, attempting to drive my MMH for maximum mpg.

Around here, 90% of the times at a red light, at a stop sign, or merging onto a highway, I have to accelerate up hill. Yea, eventually, I get up to the posted speed limit, but accelerate no more once I do.

Little old ladies driving AMC Pacer's, will go around ya, giving you the "finger".

Fully loaded cement trucks behind ya, will honk at you for accelerating too slow.

Other SUV's will cross a double yellow, into the path of an on-coming Mack truck, just to get around you.

 

First, lets remember that the FE avantage of the hybrids is only "good" when compared against their counterparts that only have the ICE.

"....Coventional wisdom DO NOT APPLY to hybrid driving...."

Oh....

Let me take, say, the latest model Ford Probe I can find equipped with an I4 and a manual transmission. Now I start using your hybrid "pulse and glide" technique by shifting into neutral when I get an opportunity to "glide". FE improvement, yes, equal to the gain using the same technique on your hybrid.

Yet TBD...

You're using the "pulse" technique in order to build (extra..??) inertia, momentum, so as to be able to convert a percentage of the resulting inertia/momentum into stored electrical energy... What makes you think, believe, that just driving at the posted speed and then using the regenerative system for primary braking when natural, native, reasons to do slow or stop come up would not result in equal or even better mileage.

To paraphase...

On a typical hot summer day on an "average" basis NYC requires 5 Gigawatts of electrical power. 3 Gigawatts during the daylight hours but less than 3 otherwise.

Obviously they need to have 5 Gigawatts of generating capacity to handle that daytime load. But to conserve energy they use the excess night time generating capacity to pump water upwards, back up into the lakes and reservoirs, to be used the next day as instead of burning coal, fossil fuels.

But doesn't pumping that water back up the hill also consume energy?

Yes, that water flowing back down through the turbine wheels is not FREE, except in the "instant" case. It is available only because they already "spent" the energy, Fuel, needed to put it into "storage".

Same as the energy being stored in your hybrid battery during the "glide" after the "pulse" duration.

There is a difference between "creating" the need to use regenerative braking via pulse and glide and having "natural" city stop and go driving situations determine when regenerative braking will occur.

 

Maybe I misunderstood this. I thought the "pulse" technique was due to the eCVT, and not the rest of the hybrid system. Basically, I thought the "pulse" technique was to trick the eCVT into getting the ICE's RPM as low as possible (and you keep "pulsing" to keep it there). Kind of like on a regular vehicle, temporarily releasing the gas pedal so that the trans will upshift into overdrive (to max mpg), and then gently start to re-accelerate again?

 

OCC, accelerating at 1800rpm on a hill is not accelerating any at all. 1,800rpm's is my first choice if I can use it. There is a torque curve on CMPG that gives you an idea at what RPM to accelerate. The next best RPM for torque starts at 2300 up to 3,000, it climbs steady in that range. In traffic, I accelerate to about 2,400rpm's, but if I'm in someone's way, I'll go higher for a short period till I reach speed. The important thing to do is take the least amount of RPM needed within the best torque ranges and hold that RPM steady till the eCVT find the most efficient way to increase speed. In other words, the eCVT and the computers know best for FE. Set your foot on an acceleration pedal angle and let off as you reach the desired speed. The RPM range you want to stay away from is 1,900 - 2,200 and 3,000 - 3,500, it's like a slipping clutch in those areas.

Be aware you will hit 100% load and get some minor elec. assist, when you jump to 2,300 and higher RPM's, but only for a short time till the eCVT adjust speed and gear ratio's.

As far as drafting and KAM, I found out before reading the PCM/ED manual, that if I lost a truck I was drafting, for some reason I could still maintain that speed and RPM if I just held that pedal position. Here is what I'm talking about:

Driving down the highway with no draft at ~70mph = ~2,100rpm (sometimes higher with headwinds), which is in the bad RPM torque range.

After finding a suitable vehicle to draft at ~70mph, wind resistance and load is drasticly reduced, and RPM's drop to ~1,800rpm's (good torque range). Short Term Fuel Trim (RPM, load and Air/fuel ratio) is then adjusted by the PCM with the oxygen sensor. Your now burning less fuel with less load at a reduced RPM.

The big truck now exits the freeway and your left with no draft. For some reason, the RPM's remain the same at the same speed and your instant MPG continues to be at much better numbers than the original 2,100rpm's at 70mph. THIS IS WHAT I'M TALKING ABOUT. The normal operating range for short term fuel trim is +/- 25%, so you maybe at a negative stoichiometric air/fuel ratio which is below 14.7:1. Short term fuel trim values are not retained after the engine is turned off.

However, while the engine is operating in closed loop fuel, the short term corrections can be learned by the PCM as Long term fuel trim. These corrections are stored in keep alive memory (KAM) in tables that are referenced by engine speed and load. Advantages:

1. Short term fuel trim does not have to generate new corrections each time the engine goes into closed loop.

2. Long term fuel trim correction can be used in open loop and closed loop modes.

For those that have a SG, you know you don't have to be that close to a truck to draft. I work hard at staying at an acceptable distance to the trucker and assist them in changing lanes when they signal by moving over behind them and holding traffic so they can change lanes.

When you learn these techniques, your highway driving MPG can only increase. Drafting can be the best tool to also block those nasty headwinds. KAM can help you with those times you can't find a draft on the highway.

GaryG

 

-John

 

Walk across the room...

The more correct analogy would be...

Turn the lights on in order to see how to safely walk across the room while pulling a rope that in turn is lifting a weigh. Then let go the rope and let gravity power the light while you walk back acoss the room safely.

 

Gary,
Can you elaborate at all about those RPM ranges? When I accelerate, I attempt to keep the RPMs as low as possible. Often, that keeps me in the 2,000 -2,200 range. Might this be one reason why I can't seem to get over 34 MPG?

-Scott