Acceleration surge
 

I had a very odd experience today ... I was doing my normal commute to work ... and exited from the freeway ... as I was slowing down and about to stop at the end of the freeway exit, my FEH kind of 'surged' forward slightly .. and then stopped normally.

Anyone ever experience something like this before?

david

Re: Acceleration surge
 

Was it a braking thing or an accelleration thing?

Re: Acceleration surge
 

I have noticed a decrease in braking force just before stopping several times. I always chalked it up to the point at which the regen braking lost it's effectiveness and the pads taking over all braking.

Re: Acceleration surge
 

See, I've experienced the opposite - but only when the road or car is wet.

In wet conditions, just as I'm about to come to a stop, the brakes grab really hard, making me (not the car) lurch forward from the quick deceleration. It feels like a jammed the brake pedal to the floor.

Re: Acceleration surge
 

Acceleration. It surged forward just a bit. Since my foot was on the brake, I was able to counter it quickly.

david

Re: Acceleration surge
 

Was it the ICE revving up to assist with "engine" braking? I notice that when I'm in Low and the battery is charged or the electric motor can't offer enough resistance, the ICE comes on and revs up... this results in a sort of surge.

Re: Acceleration surge
 

I think I've experienced this. Kinda hard to explain it because conditions have to be right and it works in stages.

I generally use a light amount of braking over a long distance when I'm coming to a stop. If the system is warmed up and I *start* to brake the ICE will usually shut down. But if the battery has managed to get a high charge and doesn't really want to take much more charge, then the ICE will re-start. And all of this happens during the same approach to the stop. So it's brakes on, engine stalls, slowing continues, engine restarts.

It's at the engine restart that the car gets a small surge. It isn't like the car is in any danger of getting away from me -- but we're acclimated to the idea that if we use equal braking pressure on the pedal, then our slowing should continue at the same rate. When the computer changes it's mind about whether it can take more charge on the battery and decides to change what it does to stop us, I feel the surge.

This question and the braking-in-wet conditions question would be great questions to ask the engineers at the Fuel-Econ Experience class.