"Short-shifting" a Jeep Patriot & Audi A4 CVT (forcing early "upshift") saves gas
 

I just drove a friend's 2012 Jeep Patriot from Ontario to Nova Scotia, about 1800 km (~1100 miles). It has a 2.4L 4-cylinder engine, automatic CVT.

http://ecomodder.com/forum/attachmen...1&d=1332780749

That's the farthest I've driven in a CVT equipped car before. Interesting.

I mistakenly assumed that the thing would generally aim for the lowest engine RPM it could get away with for a given load for best economy. Nope.

But one thing I discovered fairly early on was that you could force an early "upshift" when cruising/accelerating below ~75 km/h (47 mph) by using the manual "Autostick" gate, which is also where "D" is:

http://ecomodder.com/forum/attachmen...1&d=1332780749

Push right to "upshift", left to "downshift".

Now, if you just shifted to "D" and left it alone to do its own thing, it did not do "fake" upshifts/steps as you accelerate, like some companies do with their CVT's.

But if you bop the lever left or right in that gate, the dash display changes from "D" to up to 6 "gears", which is of course kind of silly in a CVT.

But I played around with this gear selector and learned some neat things about it that could be useful, fuel-economy wise, for anyone driving one of these:

Most importantly, when cruising or accelerating at speeds below ~75 km/h (~47 mph), tapping the lever to the right would cause the CVT to "upshift" sooner than it would by default if just left in "D", effectively short-shifting.

• Accelerating from a stop or when cruising below 75 km/h, I could merrily, repeatedly, bap the lever to the right, and it would upshift ASAP - though it wouldn't let me ever lug the engine. (E.G. if the computer determined road speed was too low or load too high for "6th" fake gear, it would just stay in "5th".)

• But if you just keep randomly tapping the lever to the right while accelerating, it will permit the "upshift" at the lowest possible RPM threshold.

• It was surprising how willingly it seemed to grant me high load, low RPM acceleration when "shifted" manually. Much lower than when left in "D". I didn't try any pulse & neutral engine-on gliding, but it may potentially pay off with this transmission.

• One warning though: once past 75 km/h / 47 mph, you have to remember to shift back into "D". If left in "6th" manual gear selection, engine RPM would be slightly higher (few 100 RPM) than when in "D" at cruise.

I also did a speed vs. MPG graph for this car:

http://ecomodder.com/forum/showthrea...2-a-21152.html

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Update: Oct 4, 2013...

2004 Audi A4 3.0L CVT

http://ecomodder.com/forum/attachmen...1&d=1380900692

I just spent about 30 minutes driving this car, and was completely surprised to learn after the fact that it has a CVT instead of a "regular" automatic. Audi programmed it to simulate gear shifts, and I have to say they did a thoroughy convincing job. I fell for their trickery.

Regardless, here's another car with a manual shift gate that permits significantly earlier upshifts than the default programming of automatic mode.

Automatic mode shift RPM:

- Left to its own devices, under the lightest possible load, the shift from 1st to 2nd happens at ~1800 RPM, and subsequent shifts at ~2100 RPM.

Manual mode shift RPM:

- You can upshift at ~1200-1400 RPM.

EG, you can shift into "5th gear" at a far lower road speed in manual mode vs. automatic: 45 vs. 70 km/h (28 vs. 44 mph).

And after a short shift, the car is perfectly happy to go down the road at ~1200 RPM. (If you drop below that in manual mode, it will automatically downshift.)

And the icing on the cake: in manual mode, it will hold the "gear" you're in under heavy engine load, until you actually floor the go pedal. (There's a detent at the very bottom of the pedal travel that activates a downshift when you push past it.)

A neat transmission. Kudos to Audi for giving the automatic driver this much control. (Too bad I've read some suffered with reliability problems.)

That is quite interesting feature, I wish my 1981 Volvo would have ability to control it that way, but maybe I will mod such.

CVT itself might be quite efficient if built for fuel economy in mind as belt is more efficient than gears.

It would just require bit of planning, so that there would be no gears in first place, just two belts and fwd, lot less losses that way.

With my Volvo I could actually make switch for early shifting by applying +12V to one solenoid, by switch, that would make it gear up more agressively.

I'm sure that even with CVT it would be possible to get quite ok mileage when making it shift earlier and it is nice that they have put that feature to Jeep.

I wonder if it would be possible to tap controller box somewhere in that to make it programmable how thing shifts. Of course if engine has lean burn it would be better to run higher rpm lower load.

For the record I'd like to state that gears are definitely more efficient than belts. I used to work for a manufacturer of gearboxes in the engineering department. Calculated losses for our gears were ~.5% per gear set.

From wikipedia on belts:
While its not a world of difference I just wanted to clarify things. :)

Hypoid gear I guess is one having issues, 85-90% efficiency I believe?

With belts you would not need that as you can do differential effect by changing ratio of belt pulleys.

Then you have to add up all the gears which makes that 15-25% drivetrain loss, where with belts you probably could get away with less?

Not quite sure about this of course, but it is something that I have been thinking and which might give something, but it would require rather good facilities to actually make such gearing.

I have sports shifter in my Fit and I use mainly in city driving and I always shift it at 2,000 rpm or constantly tapping my shifter to shift. Not sure also if its bad but I drive off in 2nd gear so when I reach 35mph I'm already in 5th gear.

I think it would be fun to control the transmission logic like performance traction control. maybe a 1-5 setting for higher gear ratio to lower gearing. Combined with fuel mapping between sportier setting and a more economy minded selection. So many ways to give drivers more control, so little probability that we will see it.

The Escape Hybrid will drop the RPMs to idle/the lowest ratio if you let up on the gas while accelerating, similar to what you would do when shifting a manual. Its known as "fake shifting", it might work on other CVTs that don't have the "manual" shift option.

I just updated the first post with info about an Audi A4 automatic I just drove.

So far, it's probably the most flexible automatic I've ever tried, in terms of letting the driver control RPM and engine load.

Chevrolet Cruze 6-speed automatic
 

https://cdn.shopify.com/s/files/1/17...g?v=1519161505


I had a chance to drive a 1st gen., pre-update Cruze this week (first time in a Cruze for me).

6-speed, conventional torque converter automatic with a manual mode like the Audi & Jeep CVT's.

Not surprisingly, like the CVT's, the default programming upshifts a lot later than you can make it shift manually. Though I can't count how many times the car told me "SHIFT DENIED" when I asked for an early upshift. Funny.

The other interesting eco-driving transmission factoid: you can force the car to start off in 2nd gear by requesting an upshift when stopped.

I do remember spamming the shifter a lot in that car when I drove it before. Frustratingly slow-shifting and slow-responding box.

Very comfortable car, though, for what it is.

:D great description of exactly what I was doing.



I didn't notice the trans was particularly slow to respond, though I did confuse it enough to make it lurch once or twice by hitting upshift just after getting moving off in 1st. I think it went 1-2-1 within a couple of seconds.



I said the same thing to Tim about it. Relatively quiet, compliant ride, substantial feeling. And no squeaks or rattles despite 200k km / 120k miles on it.

My ex had one of those, with the 1.4T and the 6T45 you drove, I remember it not allowing 6th before like 37mph... it would deliver good mileage in 6th if you kept it to like 45-50mph and kept it out of boost...

What I didn’t like is the gearing... when accelerating at WOT it would shift three times by the time it got to 60... engine had a really narrow power band, you had to really work the shifter to keep it happy, it had lots of turbo lag below 3500, and fell on its face above 5500... they say that a ZZP tune helps lots with the power curve, but I know it also voids the warranty on a car that still had one left...

I could get it into 6th around 50 km/h = 30 mph. But I'm pretty sure this was the 1.8 -- different programming?

It could be different programming or I could just be remembering 37 and not 31... it’s been a few years ago that my ex had her Cruze... how was it with the 1.8? Slow as crap? I think the Cruze weighs 3100-ish and the 1.8 is rated at 138/125?

Honestly, I'm not the person to be asking about whether a car is 'slow' or not. Remember I drive a 50 hp car with extra tall gearing, and I think it's fast enough! The 78 hp Mirage I tested felt extravagant.

I had wanted a 6sp. manual tranny, 1.4 turbo Eco-Cruze. The Chevy dealer didn't have one, but I got to drive a 6sp., 1.8 liter Cruze. Seemed very solid & I liked the 6sp. manual. The dealer tho, wouldn't deal with me for a lower-priced Eco-Cruze, so I got a good deal, better looking, 2013, 6 speed auto tranny, 1.8 liter Elantra, which I thought would give 2nd best efficiency to the Eco-Cruze. The Elantra auto tranny would shift into 6th gear at 43MPH. But when the Cruise Control was activated, speed could be reduced to 36MPH, WITHOUT the auto shifting to 5th gear. All sorts of MPG would pile up then. The Elantra was 2950 (?) pounds, 148HP, 131lbs-ft of torque. Tho little differences, the combined lower weight, more HP, more torque, made the Elantra acceleration tolerable. Averaged 39MPG, with a high of 45MPG, which made the acceleration really tolerable. Liked it so much, we also bought a 2016 6sp. manual tranny Elantra. The manual gives better MPG than the auto, & with lower gearing, gives good acceleration.....excellent for steep mountain pass highways or on-ramps.

I never feel bothered by the lack of power after test-driving something bigger and more powerful. The lack of inertia when you light off the line is addictive.

Granted, it doesn't have much go after that.

I wonder, actually, if the largely negative press the Mirage gets in the US would change if Mitsubishi only lent out manual test units. The CVT is a bore, but the manual is kind of quick given the power on tap.

Are there any manuals with three shafts? DCTs have much wider ratio spreads without becoming overly large by having an extra reduction gear.