When you get a divorce you do a lot of thinking, mostly about things not about the divorce. Here is a brain dump. This is mostly for tuners, and the geeky...

Where I work, there is an internal policy... The vehicle shall never clunk under any circumstances....

What is a clunk? Its driveline torque reversal that makes a "clunk" when lash is taken up. Clunk happens on tip in, or tip out. To prevent clunks on tip out we use something called dashpot. To eliminate clunk on tip in, there is internal logic (functions) to limit ow fast the throttle can be opened relative to pedal movement (and other variables).

When its all said and done. There are two tables that control how fast the throttle will move based on Pedal Position, speed, gear ratio, and (if applicable) torque converter slip.

Lets talk tables! EDIT: In Relation to a FBHR style strategy....

TIP_IN_TQ_RATE_CHANGE_MULTIPLIER_VS_PPS - This table is for pedal position and vehicle speed. When moving the throttle (DRIVER_DEMAND_XXXX) table you are starting at one torque point, and finishing at another torque point. So when you move the pedal your commanding torque, NOT throttle angle. The output is multiplied by .0163 (is actually the execution of the function time 16.3ms) to get the amount of that is allowed to be changed every 16.3ms. It continues to operate like this, adding a small amount of torque every 16.3ms, until it reaches final torque value (which is defined by pedal position and RPM (Or is some cases driveshaft RPM))

TIP_IN_TQ_RATE_CHANGE_MULTIPLIER_SR_NOV - This table is sued to limit rate of change of torque.... Its based on N/V (engine speed divided by vehicle speed) and torque converter speed ratio (engine speed minus input shaft speed divided by engine speed). If the converter is slipping (meaning the speed ratio is less than 1), then it becomes a "damper" and can absorb the clunk from the driveline without having to limit the rate of throttle is opening. (Cool huh?). However, is the converter is locked or has a speed ratio greater than 1.0 clunk can occur. So the output of the TIP_IN_TQ_RATE_CHANGE_MULTIPLIER_SR_NOV table is multiplied together with the output of the TIP_IN_TQ_RATE_CHANGE_MULTIPLIER_VS_PPS table to get the total amount of torque increased to allow every 16.3ms.

For the hardcore, and fun... Set TIP_IN_TQ_RATE_CHANGE_MULTIPLIER_VS_PPS to all 100,000 and TIP_IN_TQ_RATE_CHANGE_MULTIPLIER_SR_NOV to 1.0's. This will eliminate any ramp up of torque (makes a good race tune).


Cheers,
-Matt