ECTs and hills

[SilverStack]

How does an ECT automatic gearbox know it's going down a hill?

[Dr-X]

It simply takes readings from various sensors and alters output depending on what the sensors say. It doesn't know when it's going down a hill, but it has vacuum sensors, throttle sensors, a governor, etc to tell it what you're doing.

[SilverStack]

Hmm!

It's the fact that if the car is coast/decelerating on the flat, almost everything except the gradient could be the same as rolling down a light grade. But the car knows ... it may be a clever mix of sensory data from the usual supsects, but what could differentiate.

My manual doesn't go into technical details, but it gives me plenty of advice about not putting plastic suckers on the window (lens effect may start a fire), only put cups in the cup holder (items might fly around the car), and there's even one about harming the ecological balance of the world if you use the wrong oil!!

Anyway, if you can dig a bit deeper ...

Silverstack!

[UTERUS]

What the?

[Dr-X]

It's the fact that if the car is coast/decelerating on the flat, almost everything except the gradient could be the same as rolling down a light grade. But the car knows ... it may be a clever mix of sensory data from the usual supsects, but what could differentiate.

I'm not quite understanding what you're saying here?? Why do you want to know this information? Im curious as to what you're experiencing with your gbox now!

[SilverStack]

I've not had the car long, and getting used to it has had it's traumas - which I am just not used to. I've driven things like turbo Fairlady, Legacy RSK, Landrover, Mini, Corolla, Massey Ferg, etc - you've got to be a used car salesman to have driven more cars than me - so I sort of expected to hop in and drive with no issues. For the most part this is true, and the car is an absolute angel .

However with the slow speed stuff there had been a distinct lack of finesse to the way I was able to handle the accelerator etc in stop start traffic, and on urban hills.

I made some great gains in accerator control just by taking the drivers floor mats out (I've always put a sacrificial mat over the manufacturers one) and replaced it with a thin rubber mat . Together with changing shoes (Doc Martin style to Oxfords) and that feeling of smooth total control is coming back - whew!

However back to the car trundling down a hill, (50kph Auckland rush hour). Just kissing the brakes while the car is in 4th and the Brake Assist drops the car to 3rd (The RunX is an auto as wife can't drive manual), which is correct but just a little tacky , plus it gives the passengers a jolt. This doesn't happen if I tread firmly on the brake, or am driving on the flat - car stays in 4th.

So, if I can pin down the guilty transducer I may be able to do something to make the car think that a shallow downhill gradient is still a flat road - probably only a 3 - 4 deg is required. Until I know how the car (computer and sensors, or mechanical feedback loop) decides what a hill is, there is not much I can do.

And to be frank, now I'm more in control of the car and the car is usually going faster, the braking is far less intrusive - but the issue is still there, and I don't want to be beaten.

That is why I want to know!

Silverstack!

[Dr-X]

Aaah. My AT doesnt do that, so that's where I was a little lost. Sorry, cant help

[simonlenihan]

Simple solution, teach the wife to drive a manual car!

[SilverStack]

I still don't know how the car "knows" it's going down a hill, but the main problems have been solved - jerky gear changes and very significant transition when touching the brakes going down a slight incline.

The tyre pressures from the car yard were far to high!

Now the tyres are deflated to normal, all of the problems are still there, but almost unnoticeable -

Time to enjoy the car -

Silverstack!

[Caveman]

ooooo you have a RunX

Sounds like a very technical yet useful option on an automatic.

Does it do the same going up a hill? Down shifting without moving the trottle? Would sounds useful for keeping a constant speed on a long journey.

I hate people who keep the foot in one place on the trottle and go 80kph up a hill and 130kph down hill

[SilverStack]

RunX - they come in a few flavours - Mine is the sheep in wolfs clothing variety - looks exactly like a standard GL, but goes real well. Boy racer versions don't quite fit my image, but seem to go round corners slightly better.

You slightly missed the point - the gear change is in response to touching the brake pedal. This is part of what Toyota call Brake Assist. Now that the tyre pressures are correct, it works rather well.

As to the constant speed issue. We have a 1999 Primera Wagon with CVT. The CVT is excellent at constant speed - wife loves it, and I must admit that on a long journey it is very pleasant to drive. I'm delighted that Toyota are introducing a CVT.

"I hate people who keep the foot in one place on the trottle and go 80kph up a hill and 130kph down hill" - In some cars this is the best you can do!!! Which, although I'm not in the 130+ brigade, is why I got the RunX - 80kph, and holding, up the Bombay hill is just the pits .

I can imagine that my next car will be something like a Prius Wagon powered by a 2ZZ engine and Huntly power station lookalike, all going through a CVT box. I'm a sucker for something slightly unusual.


Silverstack!