Author Topic: Atkinson engine and CVT  (Read 15260 times)

ColinS

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Re: Atkinson engine and CVT
« Reply #60 on: August 20, 2018, 02:00:19 PM »
Thanks for doing those tests and to start with, I agree that this was a purely academic exercise.  I certainly wouldn't drive like that normally.  I make the following observations though:
At varying speeds from 45 to 65 mph with the limiter on I slowly pressed the accelerator, the limiter did not cut out until way past the accelerator resistance and was almost fully depressed. Pressing the accelerator more rapidly had a similar effect. My conclusion is it is not a limiter cut out.
There is very little travel on mine between indent and fully depressed so I would be concluding the exact opposite and that the resistance is there to indicate you are about to go to fully depressed.
With the limiter off I pressed the accelerator through the resistance at varying rates and car speeds. The CVT changed down before I got to the resistance. After the resistance there was an increase in engine noise and revs but I am not sure if the CVT reduced its ratio any more as by this time the car was taking off like a scared cat.
If you sensed that the engine revs increased and didn't sense an immediate and corresponding increase in road speed, then the ratio must have reduced.
My conclusion is still it is an economy stop.
I draw the opposite conclusion.

Skyrider

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Re: Atkinson engine and CVT
« Reply #61 on: August 20, 2018, 02:18:21 PM »
If the resistance is a warning of limiter cut out it is not a cut out, and it does not cut out the limiter, you can drive on the limiter beyond the resistance.

I think the car taking off like a scared cat constitutes a dramatic speed increase.

Remember we have two very different cars, I had a 2016 car for two years, the 1.5 facelift is a step change in performance.
« Last Edit: August 20, 2018, 02:25:35 PM by Skyrider »

Ralph

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Re: Atkinson engine and CVT
« Reply #62 on: August 20, 2018, 02:33:04 PM »
I tried it this morning and found if you keep your foot planted past the notch it invokes a fake gear change between 5000 rpm and the red line (hits the red line then immediately drops to 5000rpm)only did 2 changes before I chickened out :o

Skyrider

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Re: Atkinson engine and CVT
« Reply #63 on: August 20, 2018, 07:13:09 PM »
I tried it this morning and found if you keep your foot planted past the notch it invokes a fake gear change between 5000 rpm and the red line (hits the red line then immediately drops to 5000rpm)only did 2 changes before I chickened out :o

It's a bit difficult for me to find a non police or camera infested road to try that!  Even a 70 limit would be risky. Where I live there are only fixed cameras (lots of them) on the motorways, but we have frequently moved speed camera vans.
« Last Edit: August 20, 2018, 07:21:21 PM by Skyrider »

Ralph

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Re: Atkinson engine and CVT
« Reply #64 on: August 20, 2018, 07:42:12 PM »
I tried it this morning and found if you keep your foot planted past the notch it invokes a fake gear change between 5000 rpm and the red line (hits the red line then immediately drops to 5000rpm)only did 2 changes before I chickened out :o

It's a bit difficult for me to find a non police or camera infested road to try that!  Even a 70 limit would be risky. Where I live there are only fixed cameras (lots of them) on the motorways, but we have frequently moved speed camera vans.

Yeah a long uphill drag at 5am on the motorway and a gutless engine helps! Mind you it was still surprising how quick it got up to the speed limit before I gave up  ;)
« Last Edit: August 20, 2018, 07:44:50 PM by Ralph »

Skyrider

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Re: Atkinson engine and CVT
« Reply #65 on: August 20, 2018, 08:31:51 PM »
I am retiring from any further tests and trials involving power. Mrs Sky (aka the management) witnessed the trials and was less than impressed, she thought I had just bought another Jazz, the scared cat is out of the bag!

andruec

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Re: Atkinson engine and CVT
« Reply #66 on: August 20, 2018, 09:11:52 PM »
I tried it this morning and found if you keep your foot planted past the notch it invokes a fake gear change between 5000 rpm and the red line (hits the red line then immediately drops to 5000rpm)only did 2 changes before I chickened out :o
Is that the facelifted Mk3? I noticed that behaviour from the courtesy car I drove. It seemed to mimic the rising/falling cadence you get from a manual. I didn't feel any change in acceleration though so it seemed like just an audio illusion that Honda have chosen to create.

In my older Jazz the revs never do anything but rise while you press the accelerator which is what a 'proper' CVT should do. The RPMs don't normally get to the red line unless you're doing something unusual (like in my case occasionally climbing up from the M40 J11* at 90mph). And once at the redline they just stay there until you let off.

(*)In the opposite direction the car will happily sit at 60mph with my foot off the accelerator. It's not a seriously steep hill but it takes some grunt to get to 90mph half way up. And a modicum of idiocy :)
« Last Edit: August 20, 2018, 09:20:33 PM by andruec »

Ralph

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Re: Atkinson engine and CVT
« Reply #67 on: August 20, 2018, 09:29:45 PM »
I tried it this morning and found if you keep your foot planted past the notch it invokes a fake gear change between 5000 rpm and the red line (hits the red line then immediately drops to 5000rpm)only did 2 changes before I chickened out :o
Is that the facelifted Mk3? I noticed that behaviour from the courtesy car I drove. It seemed to mimic the rising/falling cadence you get from a manual. I didn't feel any change in acceleration though so it seemed like just an audio illusion that Honda have chosen to create.

In my older Jazz the revs never do anything but rise while you press the accelerator which is what a 'proper' CVT should do. The RPMs don't normally get to the red line unless you're doing something unusual (like in my case occasionally climbing up from the M40 J11* at 90mph). And once at the redline they just stay there until you let off.

(*)In the opposite direction the car will happily sit at 60mph with my foot off the accelerator. It's not a seriously steep hill but it takes some grunt to get to 90mph half way up. And a modicum of idiocy :)

Yes it’s the face lifted version it only gets to the red line and does fake gear changes if I go past the notch at the bottom of the pedal travel in normal driving it works as you describe

andruec

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Re: Atkinson engine and CVT
« Reply #68 on: August 20, 2018, 09:54:36 PM »
I tried it this morning and found if you keep your foot planted past the notch it invokes a fake gear change between 5000 rpm and the red line (hits the red line then immediately drops to 5000rpm)only did 2 changes before I chickened out :o
Is that the facelifted Mk3? I noticed that behaviour from the courtesy car I drove. It seemed to mimic the rising/falling cadence you get from a manual. I didn't feel any change in acceleration though so it seemed like just an audio illusion that Honda have chosen to create.

In my older Jazz the revs never do anything but rise while you press the accelerator which is what a 'proper' CVT should do. The RPMs don't normally get to the red line unless you're doing something unusual (like in my case occasionally climbing up from the M40 J11* at 90mph). And once at the redline they just stay there until you let off.

(*)In the opposite direction the car will happily sit at 60mph with my foot off the accelerator. It's not a seriously steep hill but it takes some grunt to get to 90mph half way up. And a modicum of idiocy :)

Yes it’s the face lifted version it only gets to the red line and does fake gear changes if I go past the notch at the bottom of the pedal travel in normal driving it works as you describe
That adds credence to the idea that the notch is some kind of 'only if you really mean it' guard. Although on my model it doesn't really seem to achieve much, just giving access to the last bit of power.

Skyrider

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Re: Atkinson engine and CVT
« Reply #69 on: August 20, 2018, 10:19:30 PM »
So we have -

Economy stop.
Scared cat switch.
Only if you really mean it guard.

I see a consensus emerging.

ColinS

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Re: Atkinson engine and CVT
« Reply #70 on: August 21, 2018, 08:35:10 AM »
So we have -

Economy stop.
Scared cat switch.
Only if you really mean it guard.

I see a consensus emerging.
MKIII MT - Speed Limiter Override

Sports CVT - I don't think it matters what it's called as the only time my foot would get close to it would be for a quick dab to override the limiter.

Skyrider

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Re: Atkinson engine and CVT
« Reply #71 on: August 21, 2018, 09:34:55 AM »
The accelerator resistance obviously has a different function on your MT car, yesterday on several occasions the limiter did not switch off when I had the accelerator beyond the resistance. In fact It took a concerted effort to get it to switch off, I tried several different accelerator movements both speed and amount of movement. The only thing that seems to switch it off was almost fully depressing the pedal. Most disconcerting, it felt like the pedal was disconnected, as opposed to being very responsive (no Atkinson on my car). I will not be using the limiter again, at least I know it works (very crudely). I find cruise control far easier to use.
« Last Edit: August 21, 2018, 10:46:22 AM by Skyrider »

andruec

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Re: Atkinson engine and CVT
« Reply #72 on: August 21, 2018, 12:26:57 PM »
I will not be using the limiter again, at least I know it works (very crudely). I find cruise control far easier to use.
I would never use mine. Controlling your speed is part of controlling your vehicle. If you can't maintain your intended speed or don't have an intended speed you shouldn't be behind the wheel. It's not difficult to do and it shouldn't take more than an occasional glance at the speedometer. A competent driver can tell whether they are slowing down or speeding up even if they don't know the actual speed. A good driver can use anticipation to work out when the vehicle speed is likely to change due to conditions and can pre-empt it by lifting off or applying more power.

mikebore

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Re: Atkinson engine and CVT
« Reply #73 on: August 21, 2018, 12:34:30 PM »
I will not be using the limiter again, at least I know it works (very crudely). I find cruise control far easier to use.
I would never use mine. Controlling your speed is part of controlling your vehicle. If you can't maintain your intended speed or don't have an intended speed you shouldn't be behind the wheel. It's not difficult to do and it shouldn't take more than an occasional glance at the speedometer. A competent driver can tell whether they are slowing down or speeding up even if they don't know the actual speed. A good driver can use anticipation to work out when the vehicle speed is likely to change due to conditions and can pre-empt it by lifting off or applying more power.

Don't all those comments apply equally to cruise control?

It's not about ability its about convenience.
« Last Edit: August 21, 2018, 12:37:14 PM by mikebore »

Sezlez

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Re: Atkinson engine and CVT
« Reply #74 on: August 21, 2018, 01:46:04 PM »
I will not be using the limiter again, at least I know it works (very crudely). I find cruise control far easier to use.
I would never use mine. Controlling your speed is part of controlling your vehicle. If you can't maintain your intended speed or don't have an intended speed you shouldn't be behind the wheel. It's not difficult to do and it shouldn't take more than an occasional glance at the speedometer. A competent driver can tell whether they are slowing down or speeding up even if they don't know the actual speed. A good driver can use anticipation to work out when the vehicle speed is likely to change due to conditions and can pre-empt it by lifting off or applying more power.

Don't all those comments apply equally to cruise control?

It's not about ability its about convenience.

A helluva lot of my driving nowadays is on rural roads and there’s a lot of speed cameras around us. I find the speed alarms invaluable. Set at 33mph and 54mph, they just ping to give me a reminder to ease back.

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