Sorry, but this is not the case, at least not anymore. From the crankshaft to the wheels, the average truck looses about 30% power (at best), and thats before you start to acount for ideal rpms and driving style.

Well designed motor/generators have a peak efficiency above 98% on some cases, so even if the controls loose 10% (which is unlikely) the net loss of a series hybrid would be 14%.

 

GREAT GREAT GREAT discussion guys and gals!!!

Let me tell you about MPG though....
I have drove a 1991 F150 4x4 5.0 V8 and got very decent MPG with it.
I mean in the summer/winter/fall rain snow and sleet.

I do stand by the fact/theory of mine, that the lighter the truck and the stronger the engine... the more MPG you will get.


Example: my 91 302cid 5.0L (forgot to mention 5spd!) got about anywhere from 14/15-19/20MPG!!!
Not bad for a truck wieghing 5000 lbs. and a big thirsty 302cid!


As far as the new F150 direction, I would like to see a manual transmission (would like a 6spd, but would settle for a 5spd.)
As far as DIESEL... if it can make good power (not only torque, but horsepower as well) then so be it.... but I like most old school light duty half ton truck owners are DIESEL illiterate!!!

I really don't even know how long to go without changing the oil in it!!!



PS. I also have a 2005 FX4 F150, with 5.4L and let me tell you, YES stop and go driving sucks!!! I can actually see the fuel needle go DOWN!!!

TONY Z.
#40

 

The biggest problem is that the F150 has become a porker. It needs to go on a crash diet and loose 1500 lbs. Turn it back into a 1/2 ton truck, and if you need to tow 8K+ you'll have to get a F250. For $2-3K more.

 

I've had the same experience with my 89 5.0L 4x4 5spd, I can usually average 17-18mpg in mixed driving. Friends of mine with similar trucks that had autos would be lucky to get 14. When I pointed out that maybe manuals were more efficient they would counter with a whole lot of technobabble explaining how autos have come a long way and are better than manuals now. When I asked them why they don't get near the milage I do they say they don't know, but they still swear it's not because of the transmision.

I agree 110%, but I'm not holding my breath. Apparently real world results don't have as much influence on these decisions as what the engineers say should happen.

 

The best I ever got with my 86 5.0 was 14 mpg, running on a long, hilly and winding road, couldn't even use overdrive. The average speed was 40-50 mph, and it was pretty much all accellerating or breaking, no coasting or cruising. It suprised the heck out of be when i got home and did the math, since 12 is the average for that truck, 10 when towing. See my sig for the details on it.

Vancouver Island is not an easy place to get good mpgs though, lots of hills keep you from getting a good stride. If I were in alberta or something, maybe 16+ would be possible if I kept the speed at around 55.

 

As for the techno-mumbo-jumbo about newer auto being more efficient, it is sortof true, open torque converters were the biggest loss when it came to the slushboxes, but the mere fact that all auto trannies need coolers mean that they still use up more energy than a stick shift.

 

The commonly held view that automotive drivelines lose 30% of the power is a myth. Industrial gears are +98% efficient per engagement, automotive gears are of higher quality. The biggest power loss in the driveline is the torque convertor. At full power and just as the vehicle starts to move these kind of losses could happen, but for a very short time. Think about it, the Ford 5.4 produces 300 HP if you were loosing 30% that is 90 HP!!! Something would be glowing bright cherry red real soon. The trans cooler could not handle that.

On a previous project I was on we were using cutting edge latest technology brushless DC motors of around 250 HP. This motor's sweet spot efficiency was 92%, generators are basically the same thing so its sweet spot efficiency would be around 92% as well. Then there is the controller which would sweet spot at around the same but lets say it is 95%. The overall efficiency at the sweet spot is then .92 x .92 x .95 = 80%.

The least efficient gearing in a drive train is the diff. I read an SAE paper on this subject and they measured an efficiency of an automotive hypoid gear set at 94 - 96%
Since this would be common to both system it does figure in the calcs.

An automatic transmission with the converter locked and in high gear (sweet spot) would be better than 80% by quite a bit.

The electric motor system just past stall would be comparable to the automatic at full load just as the vehicle starts to move. The efficiencies of electric motors under this condition is approx 50%

In large systems like locomotives the cost of building multi speed transmissions that can handle the loads involved is much more than the cost of the electric drive train and controllers and likely would keep the engine in it best operating point better than gearing. Another advantage of the electric drive in these application is much lower shock loads to the shafts and other components resulting in longer life.

Bob Parry

 

Well that is what I was talking about, but I didn't mean just a diesel engine, but that would work best, since it has the best low end torque of any motor configuration that I know of. I sure didn't think about getting rid of driveshafts and stuff, nor would I want to at this point in time, just a really awesome series hybrid thats better than the ones we got now.

 

I don't know of many trannies that can survive continuous duty at peak Hp, or many engines for that matter (other than commercial of course, but I could be wrong), but even a 7000lb pickup needs less than 100Hp to hold 60 MPH, so the net loss along the drivetrain would be more like 30 Hp, under more average conditions.

If you were to go to any dyno test shop, they can tell you all about the 30% rule, either that, or all the Hp numbers that we are beind sold are overestimated by 30% (or maybe all the dyno shops are lying ).

The motors I was talking about are designed specifically for EVs, and High efficiency, indeed there are some out there that can spend most of there time above 95% efficiency, and even peak above 98%.

These motors also do not have a "power band" per say, though starting from zero rpm can push the efficiency down to 50%, its not a fair comparison, because a gas or diesel engine cannot even operate at those speeds (thats why we use a clutch).

For cruising, there is no penalty for high operating speeds with an electric motor, since they are completely balanced, so shifting gears is not needed anymore.

As for removing the conventional drivetrain, I think it only makes sense, since you can go from having thousands of moving parts, to FIVE moving parts: one motor in each wheel (shares the same bearing as the wheel) and the generator in the place of the tranny.

There are a lot fewer things to go wrong with that setup, and it gives a nearly unlimited CVT drive ratio, so you always have the right "gear" for the current situation.

 

Electric wheel motors are great for automobiles as long as you live in a place where it never rains, gets hot, or gets cold. If you live in any of those places, then you're begging for trouble.

The electric drive haul trucks we just got at work are broken all of the time. On top of that, they are downright uncontrolable when it rains and gets slick, but that doesn't matter anyway because when it rains the electronics stop working in pretty short order...

 

I was thinking over the weekend about the 30% power train losses as stated by the dyno testing people. I had forgotten about my days testing transit buses on chassis dynos. I never lost any tires but one of my fellow workers said that in previous testing he had done they had failed 7 bus tires on the dyno due to over heating!! My memory of those days is of the stench of hot tires. Chassis dynos are very hard on tires and that is why they do not test for very long. So during a dyno test there may very well be losses as stated of 30%, but those would be mostly between the tires and the dyno. Twin roller dynos are the worst for heating tires. The less common single roller dyno would have less losses. My numbers for drive train losses in previous posts should be accurate.

Bob Parry