Author Topic: Sensor ? Jazz EX CVT 2012  (Read 3809 times)

guest5355

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Sensor ? Jazz EX CVT 2012
« on: April 07, 2016, 09:32:58 PM »
Hi. Please does anyone know if a sensor if fitted to the break pedal, this sensor may cut the power to the CVT for a split second (ish) if you use your left foot to break (health reasons) and at this moment you just happen to hit the gas with your right foot (it causes a loss of power)
 Getting very fed-up with this problem.

John Ratsey

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Re: Sensor ? Jazz EX CVT 2012
« Reply #1 on: April 10, 2016, 08:52:33 AM »
In these days of drive-by-wire I would assume that there are sensors everywhere. The computer decides what the car should do according the various inputs and pre-programmed rules. Normally, cutting power if the brake pedal is touched would be a logical action.

You could ask your dealer whether they could access the software sufficient to adjust the rules to suit your driving requirements.



2022 HR-V Elegance, previously 2020 Jazz Crosstar

culzean

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Re: Sensor ? Jazz EX CVT 2012
« Reply #2 on: April 10, 2016, 09:36:46 AM »
Hi. Please does anyone know if a sensor if fitted to the break pedal, this sensor may cut the power to the CVT for a split second (ish) if you use your left foot to break (health reasons) and at this moment you just happen to hit the gas with your right foot (it causes a loss of power)
 Getting very fed-up with this problem.

Would be a pretty strange CVT setup if drive was not cut when brake applied,  on my wifes Fiat CVT this is exactly what happened and it was a faulty brake pedal switch that caused the car not to want to take up drive sometimes (very embarrassing in traffic and at junctions) -  I would guess the power is removed from CVT for as long as your foot is on the brake, not just for a split second as otherwise engine would by trying to drive against brakes - I doubt if Honda (or any other car maker) would change this setup as it would not be safe (for instance if throttle stuck and you applied brakes to stop car and engine was fighting against brakes it could cause a crash). 

I know there are two schools of thought about both or one foot on pedals, but I never quite understood driving an auto with both feet,  always kept my left foot out of the way when I drove them while living and traveling abroad,  and when driving my wifes Fiat CVT in UK (CVT was best part of that car,  it had a magnetised powder clutch,  which was very smooth indeed,  but rest of car was badly built). 
« Last Edit: April 10, 2016, 03:10:09 PM by culzean »
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

madasafish

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Re: Sensor ? Jazz EX CVT 2012
« Reply #3 on: April 10, 2016, 04:56:31 PM »
No dealer worth their salt will change the system. It's for safety. (And I doubt whether they have teh competence if they wanted to)


Pine

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Re: Sensor ? Jazz EX CVT 2012
« Reply #4 on: April 10, 2016, 07:18:48 PM »
If you are braking you should not be applying the throttle at the same time. Either brake or accelerate but not both together. If you are having difficulty perhaps it is time to consider hand controls. A disabled friend of mine has hand controls fitted to his Toyota Auris Hybrid, he is well in control and gives me a very smooth journey whenever I am in his car.
« Last Edit: April 11, 2016, 05:35:00 PM by Pine »

applicationcen

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Re: Sensor ? Jazz EX CVT 2012
« Reply #5 on: April 10, 2016, 08:43:02 PM »
I don't have a CVT and I cant find any tech specs on the net - so this is guess work based on real principles:-

Don't press the accelerator and foot brake at the same time.



what I researched -

All Honda CVT systems utilise a belt that gets 'pinched' at both ends by V shaped clutches. Imagine a wide belt that can ride up and down V shaped cones at either end of the belt. 

Clutch 1 obtains power from the engine. As the engine revs increase it pinches the belt, the belt moves. (Drive)

Clutch 2 obtains power from the belt and transfers it to the driving wheels. As the belt moves it transfers the rotation to the driving wheels. (Driven)

The mechanism is balanced. What that means is, if you stomp on the accelerator the drive valley will be wider (Belt low) and the driven valley pinched hard (Belt high). This pushes maximum power through the system.

Assuming you keep your foot fully to the floor the drive valley will pinch to the top and the driven valley will open up allowing top speed.


Before any ECU trickery, (that is before engineers providing software & flappy paddles and brake sensors) - the 'balance mechanism' is very Victorian. Springs, counter balances, centrifugal force, slide-rules and excellent engineering do the thinking for you without the need for software.

Victorian bit - Load imparted  through the driven wheels gets emitted back through the 'balance mechanism' and alters the drive/riven ratio gearing.

Honda also has extra clutches to facilitate start, forward and reverse. (Rather than use a torque converter)

The 'ECU trickery' will know exactly what you are doing with your brake peddle.

The Victorian bit wont know about Brake Priority Logic planned for in the ECU. It might be a legal requirement / non-requirement for the ECU to react in a particular way to brake + accelerator positive inputs.

The bottom line is that the 'go' peddle in a car a car is not meant to be pressed at the same time as the 'stop' peddle because if you need to use a brake in that situation it is the hand brake.

Contact Honda.





chrisv

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Re: Sensor ? Jazz EX CVT 2012
« Reply #6 on: April 17, 2016, 03:20:30 PM »
Hi,
I thought that around 2011 the cvt included a torque converter, certainly drives like it (smooth)
Chris

VicW

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Re: Sensor ? Jazz EX CVT 2012
« Reply #7 on: April 17, 2016, 06:25:15 PM »
The basic principal of the CVT transmission has been around for many years, probably close to eighty. A British car maker, Lanchester, was heavily involved in its development. DAF cars, taken over by Volvo in about 1975, also produced cars with CVT, I had one. The system was nowhere near as sophisticated as it is today and relied heavily on engine manifold depression to the alter the drive ratio.
The Jazz changed back to the CVT from the iShift system in 2011 and also changed to a torque converter clutch which in itself is a form of CVT allowing a very smooth take off and flexibilty.

Vic.

Beaver

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Re: Sensor ? Jazz EX CVT 2012
« Reply #8 on: April 22, 2016, 10:04:15 AM »
Using both feet on the pedals seems fine for a racing driver, who might feel the need to save split seconds here and there, but when driving a Jazz, I personally can't see the point.   I use my right foot for both pedals, and have never had a problem with that.

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