(the early life of Electronic Throttle Control at Chrysler)
The Beginning
Driver
Pedal
Driver pushes on Pedal to move vehicle
Pedal formerly known as Gas Pedal, and before that, Accelerator Pedal

Floored
Pedal Position
Where Does the Force Come From?
Engine produces some torque, at a
speed:
T , engine engine
Transmission:
T T n trans
engine trans
2 2
Vvehicle axle TireDiamet er
2
Ignoring Losses, of Course
Interesting, but not the end of the Story.
Where Does the Force Come From?
Note:
T T T engine trans axle engine trans axle
Not just performance, but giving the driver the expected response to pedal inputs
In automotive applications delves deeper into transmission shift schedules as fuel economy is heavily impacted
trans
engine
ntrans
Ignoring Losses, of Course
Where Does the Force Come From?
Axle:
Taxle Ttrans naxle Tengine ntrans naxle
axle trans
engine
Driver Intent Relates to Pedal
Speed up a lot
Position
Speed up a little
Driver Intent
Maintain speed Foot off Pedal
Slow
down
Pedal Position
Floored
Driver Intent
Ptrans Ttrans trans
Tengine
ntrans
engine ntrans
Tengine engine
Ptrans Pengine
Ignoring Losses, of Course
Driver Intent is essentially acceleration rate (+ or -)
Since pedal position is related to driver intent, pedal position is related to desired vehicle acceleration.
naxle
n n trans axle
Ignoring Losses, of Course
Where Does the Force Come From?
Tire:
Fvehicle
Taxle
Tengine ntrans naxle
TireDiamet er TireDiamet er
usage, washer solvent spray, and any fluid leaks)
So, Force is proportional to acceleration
Force Relates to Pedal Position
Force Applied to Vehicle
Foot off Pedal
A little side story to
get you in the right mindset
which illustrates the difference between
motorheads and everyone else
The Story of Power
and the Power Paradigm
Where Does the Force Come From?
Power- the rate at which work is done:
Power is Force times Velocity (linear)
Power ForceVelocity FV
Power is Torque times Rotational Speed (rotary)
Acceleration Relates to Pedal Position
Vehicle Acceleration
Foot off Pedal
Floored
Pedal Position
Vehicle Acceleration
Newton’s First Law:
F=ma
Vehicle mass is constant (ignoring fuel
Powertrain Matching
John Bucknell DaimlerChrysler Powertrain Systems Engineering
September 30, 2006
What is Powertrain Matching?
Selecting the right engine and gearing for a given application
Power Torque Rotational Speed T
Where Does the Force Come From?
Engine produces power:
P T engine
engine engine
Where Does the Force Come From?
Transmission: