aurion - accelerator control

[lembasts]

Greetings,

As this is my first automatic car Im not used to how the accelerator can control the automatic transmission. I recently entered a freeway and decided to see what would happen if I put my foot to the floor. Well it certainly was nothing like my previous 4 cyl manual camry. However, it seemed to go down a gear and rev up high. Does planting the foot change the gear down? Is there other ways in which accelerator action alters the gears?

Thanks

David

[DJKOR]

Mate, what you are experiencing is 'kickdown'. This is part of the operation of all automatic transmissions. Of course planting your foot down in a manual isn't going to drop down a gear or two, but this is because there is nothing but yourself to change the gear.

Putting your foot to the floor on an automatic car indicates that you want to accelerate quickly. As a result, the transmission will drop down a gear or two (or three) to enable it to accelerate quicker.

http://ask.cars.com/2008/09/transmission-ki.html

Kickdown is a downshift in an automatic transmission triggered when the driver pushes the accelerator to the floor.

Automatic transmissions kick down to a lower gear to make use of the greater power delivered at the engine’s higher rpm; this typically occurs when the driver attempts to accelerate from a constant speed, as if to pass.

Before computer control became widespread, most automatic transmissions would kick down only if the accelerator was pressed all the way to the floor. More modern transmissions may kick down, by one or more gears, earlier in the pedal’s range of movement, based on the pedal’s position or rate of change. Some vehicle central computers compare the current speed with the position of the accelerator, and if the vehicle is not accelerating as much as it should — as when it’s climbing a hill or carrying a heavy load — the computer will signal the transmission to kick down.

[Silver-Aurion]

I've done a few kick downs in the Aurion, all I can say its a scary feeling when its during heavy traffic because of the sudden acceleration and it feels really really weird when it drops down and then speeds up fast.

The kick down in my old 4cyl camry was a laugh, the car would kick down a gear and keep kicking down until it stopped, she was so slow :P

Edited March 29, 2010 by unique

[lembasts]

Thanks. I guess its something to be avoided unless you really need it.

David

[DJKOR]

I guess its something to be avoided unless you really need it.

Well if you are all for the 'save fuel' side of the table, then sure... it would be something to avoid.

But when the engine makes most of it's power up high and you get a good feeling from revving it out... it's not something I would say to avoid

[imposter]

Only avoid it when going uphill in the wet, as I learned today :P

[SCOOTA44]

The inner hoon comes out occasionally ( without passengers of course ) sneak up on one of my collegues on the highway, kick it back and give them an earfull of intake and exhaust as I fly by. :P

[Silver-Aurion]

I'm not sure if its my driving style or not on the way I press the accelerator with my foot but my Aurion seems to love to kick down.

In my residential area, its a lot of turning, braking and accelerating (roads are never straight but are twisty) before I can get home(All new estate's are like this, so annoying).

Anyway, coming out of the corner and slowly reaching up speed, as I accelerate while exiting the turn the car will decide to kick down but I refuse to let it use the extra power and I ease off the pedal when it kicks down.

It's like the car is telling me to speed when I don't want to it to

Why is it doing a kick down as I apply the accelerator again while coming out of a turn? Each turn is a SHARP L turn at about 25/30KM/h.

[DJKOR]

Why is it doing a kick down as I apply the accelerator again while coming out of a turn?

It's a combination of speed and load that the ECU will gauge to decide whether to kick down or not. Depending on how much slowing down was done prior to entering the turn, the transmission may still be in either 5th, or 6th. Both these gears are overdrive gears, and at such a speed, the transmission will tend to want to use a lower gear for acceleration. Since most of the torque is made up around 4200RPM, it is programmed in such a way to utilise that for acceleration which would result in the downshifting.

Ever ridden a mountain bike? If you were in a high gear casually cruising along, not needing to pedal with much force to maintain your speed then had to slow down just that little bit, would you prefer to stay in the same gear, or switch it down a couple? Same deal basically with the auto.

[Silver-Aurion]

Why is it doing a kick down as I apply the accelerator again while coming out of a turn?

It's a combination of speed and load that the ECU will gauge to decide whether to kick down or not. Depending on how much slowing down was done prior to entering the turn, the transmission may still be in either 5th, or 6th. Both these gears are overdrive gears, and at such a speed, the transmission will tend to want to use a lower gear for acceleration. Since most of the torque is made up around 4200RPM, it is programmed in such a way to utilise that for acceleration which would result in the downshifting.

Ever ridden a mountain bike? If you were in a high gear casually cruising along then had to slow down just that little bit, would you prefer to stay in the same gear, or switch it down a couple? Same deal basically with the auto.

Oh okay. It would have been nice if we had a choice. Like some cars you can choose which mode you want like "sports" etc.

Sorry about all the q's lately. I might as well ask now and get them out of the way. I'll be keeping her for many many years to come and the more I know about her the more I will feel comfortable driving it.

[DJKOR]

Oh okay. It would have been nice if we had a choice. Like some cars you can choose which mode you want like "sports" etc.

It's not really to do about driving performance in terms of sporty etc. It's more about the engine selecting what is most "friendly" on itself and the gearbox. Surely it won't be holding gears like a manual... but this is what you get when you have an auto. The car is doing the gear changes for you. When you make the car do the work for you, it will do it how it's programmed to.

[Silver-Aurion]

Oh okay. It would have been nice if we had a choice. Like some cars you can choose which mode you want like "sports" etc.

It's not really to do about driving performance in terms of sporty etc. It's more about the engine selecting what is most "friendly" on itself and the gearbox. Surely it won't be holding gears like a manual... but this is what you get when you have an auto. The car is doing the gear changes for you. When you make the car do the work for you, it will do it how it's programmed to.

Fair enough :)! It's just good to know no damage is being inflicted on the gearbox. Because when the car decides to kick down but I don't utilise that kick down (It's like as if I'm tricking the car) and accelerate off normal.

Bit unrelated but my fuel consumption is going sky high, my average for a couple of months was in the 10's and 11's but now its in the mid 12's.

My short trips and harsher acceleration off the lights is the cause. I've come to realise, the Aurion lags in low revs but it accelerates superb if you decide to open the throttle up bit more.

I think it was this forum that I read way before I even bought the car that at low rev's the aurion likes to lag. I'm yet to find a comfortable/decent acceleration for myself and the car.

[dave262]

Only avoid it when going uphill in the wet, as I learned today :P

Even in the dry I constantly loose traction during a kick-down... the Aurion seems to have an uncanny ability to even wheelspin in third while it is moving, which I have never seen from another automatic before...

Does anybody else notice that if a kickdown occurs, but you quickly back off the accelerator and the revs stay high - the transmission seems to be intentionally slipping, as the car doesn't seem to really change speed?

[DJKOR]

Does anybody else notice that if a kickdown occurs, but you quickly back off the accelerator and the revs stay high - the transmission seems to be intentionally slipping, as the car doesn't seem to really change speed?

Yeah, I've noticed that quite a few times. Like where I accelerated too hard then reacted that split second before the gear change was complete. I never really saw it as an issue though since I was actually doing the opposite of what the ECU thought I was doing.

[Silver-Aurion]

Only avoid it when going uphill in the wet, as I learned today :P

Even in the dry I constantly loose traction during a kick-down... the Aurion seems to have an uncanny ability to even wheelspin in third while it is moving, which I have never seen from another automatic before...

Does anybody else notice that if a kickdown occurs, but you quickly back off the accelerator and the revs stay high - the transmission seems to be intentionally slipping, as the car doesn't seem to really change speed?

Today for the first time ever I lost traction. It was this morning on my way to the dealer. I was at a busy road a bout and cars where not giving a chance to let me through so when I found the opportunity I hit the accelerator, but not even that hard and I got wheel spin.

It looked like to others that I done it intentionally.

Also thing is, road was dry, the road was also dead straight. No up hill or anything. I think I have unleashed the Aurions POWERRrrr.

After the ECU restart and amping up my driving style to a bogan v6 driver I can definitely feel that the car is much much more loose, it doesn't feel like its holding itself back.

[diamond white]

I don't mind a LAG start sometimes...it gets me to the next green light without having to stop and clears the p & l platers rushing home from work and saves me ALOT of money at the bowser. To me thats a tripple score that gives me more time to enjoy jjj on the wireless ;0)

[DJKOR]

After the ECU restart and amping up my driving style to a bogan v6 driver I can definitely feel that the car is much much more loose, it doesn't feel like its holding itself back.

I would be more than certain that it's your own driving that accounts for the change in feel if your ECU was reset more than a few start/stop cycles ago.

... gives me more time to enjoy jjj on the wireless ;0)

You remind me of my old TAFE teacher Not in a bad way or anything. Just brings back memories to when he would yell out 'who's got the wireless going?'.

[diamond white]

After the ECU restart and amping up my driving style to a bogan v6 driver I can definitely feel that the car is much much more loose, it doesn't feel like its holding itself back.

I would be more than certain that it's your own driving that accounts for the change in feel if your ECU was reset more than a few start/stop cycles ago.

... gives me more time to enjoy jjj on the wireless ;0)

You remind me of my old TAFE teacher Not in a bad way or anything. Just brings back memories to when he would yell out 'who's got the wireless going?'.

Ha Ha I have always tried to keep "classic" words going another favorite is flash :D