Brake Throttle Override
 

There is another conversation on this topic buried amidst a thread with covering a few different topics
...but I thought this deserved a separate thread so people could focus on it.

The point is ... there is a difference of opinion as to whether the TCH has the 'override' or not.
Dealer's service department managers and the media say the TCH does...however, user experiences might say otherwise.
I have the 2008 TCH VIN starting with 4T1 (US made).
I floored the gas and then applied the brakes.
The car slowed down (which was a good thing!)
However, the engine was still racing (while my foot was on the accelerator).
This implies that the brakes are stronger than the gas...NOT that there was any software override of the throttle system.
My MPG meter indicated low fuel efficiency, the graphic showed power from the engine and I could hear the engine racing (at a very high level).
Wouldn't a true override system cancel (or reduce) the input signal from the accelerator and tell the engine to rev more slowly (or not at all)?

So, in my ever so simple experiment, the TCH does not have an override system, or at least, if it does, it's not an effective one.
Is there a speed of acceleration where the brakes aren't capable of trumping the gas...or are brakes always superior?

In any event, if there is a software upgrade to these cars, I think we should be part of it. I'm unsure why there is so much misinformation out there.

I'm NOT a mechanic, nor auto expert.

Thanks!

Re: Brake Throttle Override
 

:D
next week it will be another problem lol!

Re: Brake Throttle Override
 

What happens in neutral if you "floor" the gas pedal, does the engine rev up...??

And if it does I assume the TCH still doesn't move....

With the TCH, neutral doesn't mean the drivetrain output isn't still connected to the axles, it just means that the PSD will not allow ICE "drive" to reach the drive axles.

I'm not saying with any authority or conclusiveness that the PSD operation is limiting the ICE torque to the axles, just that it could be so.

Re: Brake Throttle Override
 

Makes sense...but then, we have no way of knowing for if it works, or not.
How do we know that it's just the braking power overriding the acceleration?

I'd expect an override system to operate in a different way than revving in neutral.
If it's an override, assuming I understand how it should work, the signal from the accelerator should be ignored when the brakes are simultaneously applied. That's how the video portrayed it.
In this regard, we are to take it as a leap of faith that the engine is revving but the transmission (or what ever connects the engine to the wheels) is not connected.

You see my confusion?

Re: Brake Throttle Override
 

Re: Brake Throttle Override
 

You're probably right...
I guess the only way to know for sure is to see how long it takes to come to a complete stop from a certain speed with moderate to heavy braking pressure (no need jam on the brakes and kiss the windshield) and then compare that to the braking distance with the same braking pressure while accelerating.
If it's the same, I guess the system works as you suggest.
If not, then the extra braking distance would be a reflection of the brakes being more powerful than the acceleration...which would still be taking place.
Right?

Re: Brake Throttle Override
 

I will add that my own little tests, similar to Larry's, gave the same results as his and also that any BTO function supposedly present in my 09 TCH was certainly not adequate to provide any relief during my floor-mat-induced UA incidents.

After the BTO flash is completed on my car this afternoon, I'll see if it works any better.

Re: Brake Throttle Override
 

Vera confusing...

It would be the absolute ULTIMATE in engineering stupidity to not "disengage the clutch" (use the AC motors to "counter" ICE input to the PSD) when the brake is depressed.

We already know that HIGH ICE RPM, say to quickly recharge the hybrid battery, does not necessarily result in higher roadspeed since the PSD can easily accommodate that situation.

Re: Brake Throttle Override
 

As I posted in the other thread, and as Willard predicted, they did not do the BTO flash.

Also, I have done some further reflection on the inadequacy of the existing ability of this car to deal effectively with brake-accelerator pedal conflicts.

I seems to me now that the system may have some ability to ameliorate the result when the accelerator pedal is stuck and then the brake is applied, but it seems to be little or no help if the accelerator pedal is pushed further AFTER and WHILE the brakes are applied.

This would explain why any inherent BTO capability on my car did not help me out in my floor-mat-induced UA incidents. (As explained previously, the mat can get under the brake pedal and over the gas pedal so that pressure on the brake pedal can further depress the accelerator pedal.)

I would also explain why Toyota needs to do the pedal and floor mat modifications on the Camry Hybrid in spite of their contention that the PSD hybrids have an inherent BTO function.

Re: Brake Throttle Override
 

How "butchered" does the accelerator pedal look after the modification? Can you post a picture?