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Old 08-04-2010, 09:22 PM   #1 (permalink)
Coasting Down the Peak
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Toyauto Pickup - '94 Toyota Pickup 2WD
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Versa Base - '09 Versa Sedan 1.6 Base
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Digital Gas Pedal

if one were to rethink the gas pedal, and use an algorithm to determine the throttle position based on rpm and load, what inputs would you use to calculate the optimum throttle position at each rpm and load situation?

The goal would be to accelerate at optimum brake specific fuel consumption. The driving method would differ from the current gas pedal/throttle method. Instead of holding the gas pedal at the optimum depth to achieve a certain speed, the pedal would be on or off. The driver would accelerate to a certain speed, and then release the pedal, coasting down to a slower speed, then depressing the pedal to accelerate again.

When the gas pedal is depressed, a microprocessor would measure the rpm and load, and using a math function, would determine the ideal throttle position.

A shutdown / starter system could be incorporated to allow the motor to be shut down completely during the pedal off / coast phase. This could be a manually operated bump start or a controlled electric starter. If manually operated in highest gear, the operator could coordinate releasing the clutch and depressing the gas pedal. An electric start would only be required if the vehicle speed were too low to bump start.

It may be simpler for the operator to actuate the digital gas pedal only in highest gear, and at other times, the classic gas pedal function could be used. A switch could be used to allow the operator to control whether the gas pedal function, selecting either classic or digital.

ODBC LOD Engine Load
Is transmission in highest gear? Yes/No
Vehicle speed

ODBC TPS Throttle Position
or a voltage output to represent a typical drive by wire throttle control voltage

Basic Engine Operating Line, modified to show ODBC LOD vs. RPM
Is transmission in highest gear? If yes, operate digital gas pedal, if no, classic gas pedal
If vehicle speed is below 5mph, use electric start upon gas pedal actuation

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Does this seem to be based on solid theory?

It does not sound particularly difficult to construct.

Nissan Versa Aeromods
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