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Old 04-23-2012, 04:00 PM   #151 (permalink)
oldbeaver
EcoModding Apprentice
 
Join Date: Oct 2008
Location: Chile
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Mercedes 89 D - '89 Mercedes 300 E
90 day: 33.86 mpg (US)

Skodie - '09 Skoda Octavia TDI PD
90 day: 38.84 mpg (US)

1993 Mercedes 300D Turbo - '93 Mercedes Benz 300D Turbo W124
90 day: 26.19 mpg (US)

Crossie - '16 Subaru XV Crosstreak
90 day: 9.61 mpg (US)

Crossie - '16 Subaru XV Crosstreak
90 day: 33.34 mpg (US)
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Fixed mpg with fixed throttle pedal

Quote:
Originally Posted by Cardinal Grammeter View Post
OldBeaver and others,

RE: Scion MPG function of Throttle Position.

There was no "thinking" involved in this since it was a direct observation.

I drove the car for 4 hours over big hills and across deep valleys and the instantaneous MPG readout in the dash could literally be "set" by "adjusting" the throttle pedal.

If you wanted 50 mpg, just press the pedal 1/32 or an inch.

It did not matter if you were losing speed going up a hill or gain speed going down a hill. The mpg did not change if you did not change the pedal position.

....

What was very useful about this information is that knowing that pedal position is your "MPG setting," you can do a pretty good job w/o any instrumentation.

Now keep in mind I'm driving 5th gear (top gear) and obviously engine revs never reach more than perhaps 2500 rpm.
....
________________________

The irony of all this is that a "smart" cruise control would be a fixed pedal position(!) So I was thinking a Hand Throttle would work.

....

One technique might be to allow speed to drop say 10 mph below the setting without changing throttle position. Once the drop was experienced, slowly increase throttle position until the set speed is achieved. There is nothing so infuriating when the Cruise bludgeons the gas pedal right at a crest.
Cardinal Grammeter,

mpg yield on a car depends, among other things, on the following:

- quality of pavement
- slope of the road
- speed of the wind
- direction of the wind
- density of the air, (temp, humidity)
- weight of the car
- gear of the transmission
- traffic
- quality of tires
- hardness of tires
- altitude
- temp of the engine
- speed of the car (resistance of air is proportional to the square of speed)
- rpm of the engine
- power of the engine
- (I may be missing some more)

On turboed or compressed cars, the yield depends if turbo is active or not also, which depends on a combination of factors, such as rpm, gear, slope, computer map (transition or final), etc.

There are variable geometry turbos also, where even intervention of turbo and its effect on yield is variable along a wide range of rpm.

This is easily demonstrated just by looking a computer or instrument that shows you mpg of yr car in every moment. If you had gotten one of these, you would have seen that even over a "flat" pavement (that looks like), keeping all other conditions "equal"(that seem like), mpg varies a lot depending on little variations of slope, wind, or any other of the above.

Moreover, even setting the computer to show MEAN mpg of the trip, it variates a lot over time, depending on the conditions I mentioned above.

Am I missing something or you are talking about something of yr imagination?
How can you keep all these conditions fixed with yr throttle pedal?
I think that you can keep only one thing fixed by fixing yr throttle pedal: yr throttle pedal itself.

Please, explain how you control all of the car, engine, climate, topography and surroundings with yr foot.

OldBeaver

__________________
Mercedes 300 D turbo 1993

Last edited by oldbeaver; 04-23-2012 at 04:06 PM..
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