Visting Prius Owner

n1das said:

I recall Tomo366 had a Jetta Hybrid for a while. From what he described it drove great like all other Jettas. I recall a major complaint was MPGs under real world driving conditions were a disappointment and nowhere near the advertised MPG numbers. It *might* deliver the advertised MPG numbers when specifically driven for MPGs and under all the right conditions (read: hypermiling techniques required). As usual, YMMV.

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I really liked the Hybrid! The 1.4 Gas engine is now being used as the base engine in the new Jetta 150 HP great little motor and with the Electric assist is wa s quick! My problem was no trunk due to the Battery and the gas tank was smaller loved the 7 speed DSG! And as stated above unless you drive for mileage.....won't get close to advertised mileage.....expensive 33,000 and no resale! My 2015 Jetta SEL TDI is at the same Fuel mileage overall as the Hybrid was when I sold it.....

Hi,

So I started looking at the 'highway' benchmark from Argonne Labs. The speeds are fast enough that the Prius can not turn off the engine. The goal is to see if we can make a BSFC chart, tank-to-tires. This is a work in progress but here is an early peek at the data:

NOTE: this is draft and an updated chart is planned.

• 42 mph is the limit for engine off operation. At 42 mph and higher, the Prius engine is always ON. At these speeds, the Prius and Jetta TDI will be running their engines.
  • There are some special cases where the engine can turn off up to 46 mph but this is poorly mapped. This may lead to a change in the chart along. I do need to add the Argonne Labs source text.

My eyes suggest the Prius is burning less fuel in the 'engine always ON' modes of the 'highway' test. Now this could be due other factors such as dyno loading. If the Jetta dyno settings put a heavier load, the fuel consumption should be higher. BUT this takes checking the data in more detail.

Not shown, I ran a quick x-y plot of TDI vs Prius fuel consumption and the chart shows there are times with the TDI has lower fuel consumption in a scattering of points. But before releasing that chart, I want to make sure the responsible modes are well identified.

Bob Wilson

ps. For the curious:

1. The USA Federal incentives for the Prius expired in 2007-08. At one time there was a $1,500 incentive for the TDI but I don't know if it ever expired. I understand some States may still have Prius sales incentives but the CARB has been cutting back and Georgia and Oregon passed a special registration tax for EVs and plug-ins. Hybrids are still an open question. The Virgina law was reversed after the last election.
2. I don't work for Argonne Labs but I am a 'data geek'. Argonne conducts good benchmarks, not perfect, but good enough. Their current data has some time lead and lags that have to be detected and corrected in the data. I've not spent a lot of time discussing these techniques as it tends to cause 'blank stares' and sleep in those not skilled in math. But I will if anyone asks. Careful what you ask for as I will provide the messy details.
3. Did I miss VW lifting the USA 'stop sales' order for the 2015-16 models? Perhaps they are still available in other countries.

Learned something from this ... I didn't know that the Prius had a maximum road speed without engine running. Now that it's mentioned, it makes sense from the way the gearbox is designed.

This might also be why the Volt, which also uses a power split/merge arrangement, has a different mechanical arrangement which has a couple of clutches in there. The Volt has to be able to run all-electric - but to improve powertrain efficiency, it also has to mechanically couple the engine during highway operation once the batteries are run down.

The way the Jetta hybrid works, and for that matter how the various Honda and Hyundai hybrids work and how the old GM and Chrysler "two-mode" hybrids worked, has the single motor/generator between the engine and the transmission with a clutch from the engine so that it can be disengaged, and the motor/generator power runs through the gearbox as usual; the motor/generator runs at engine speed (or the same speed the engine would be running if it weren't de-clutched and shut down). Many newer transmissions (notably the ZF 8-speed rear-drive and 9-speed front-drive transmissions) are designed to allow hybrid integration and this is how all of them do it - the motor/generator takes place of the torque converter and there is a mechanical clutch to the engine. These won't have the "max road speed without engine running" limitation, either.

There are generally many ways of solving a given engineering problem, and there is not always one single clear-cut winner.

The 2016 Volt will be completely different in terms of drivetrain operation. It will still be able to do 100% electric, but the engine operation will be a lot more efficient thanks to Toyota's patents expiring and Chevy jumping on board that ship. This should be a significant improvement over the first generation Volt.

http://gmauthority.com/blog/2015/02/secrets-of-the-2016-chevrolet-volt-transmission-deep-dive/

Don't shoot me for this, but I like the new Volt. However, I can't help but wonder what it would be like shooting across the Ohio Turnpike at 80 MPH in sub-zero weather and a headwind (you've been there, VeeDub). Bet FE wouldn't be stellar, and that little engine would be howling away.

IndigoBlueWagon said:

Don't shoot me for this, but I like the new Volt. However, I can't help but wonder what it would be like shooting across the Ohio Turnpike at 80 MPH in sub-zero weather and a headwind (you've been there, VeeDub). Bet FE wouldn't be stellar, and that little engine would be howling away.

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Yup... been there, done that. The TDI doesn't do so hot in those conditions either.

The 2016 Volt is very intriguing, but I'll be standing by for the 2017 when it gets the new engine.

VeeDubTDI said:

Yup... been there, done that. The TDI doesn't do so hot in those conditions either.

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Nothing does good in those conditions...

Last year driving to Detroit and back, three people and luggage in the car, running at 80, I got just over 43 MPG for three tanks. I suppose we didn't have a head wind both ways, but we did hit a major traffic issue and ice on the way back.

IndigoBlueWagon said:

Last year driving to Detroit and back, three people and luggage in the car, running at 80, I got just over 43 MPG for three tanks. I suppose we didn't have a head wind both ways, but we did hit a major traffic issue and ice on the way back.

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Can't wait for this year¡

IndigoBlueWagon said:

Don't shoot me for this, but I like the new Volt. However, I can't help but wonder what it would be like shooting across the Ohio Turnpike at 80 MPH in sub-zero weather and a headwind (you've been there, VeeDub). Bet FE wouldn't be stellar, and that little engine would be howling away.

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That would be a killer for me since we have weeks on end like that. We had a 2 week stretch where it was -20°F every morning and most times we had snow to boot (the old adage "too cold to snow" was disproven many times last year) . It's those times that make me glad I keep my cars running optimally and have an emergency kit on hand (that I have never had to use) since getting stranded can be a death knell.

I have to wonder how the battery packs do in those extremes, I know our Mini-split heat pumps at work don't like it but they're only rated to -15°F anyway.

oilhammer said:

The car is still abysmal to drive. I'd rather walk.

Honestly, for the money, a Yaris or Versa or similar is a better buy. Just as good (or bad) to drive, but cost THOUSANDS less and will still get decent fuel economy. Easily enough to overcome the cost difference.

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I've never driven a Prius, but I also have never driven a Toyota that I liked, and I've driven a ton of rental Camrys, Corollas, Echos, Yarises and RAV4s. I'd rather go to the dentist than own a Toyota. I can't believe it's impossible to make an engaging hybrid. Well it is, Toyota does a half-decent job with the Ct200h except for the transmission. Like IBW, non-availability of a manual transmission is a deal-breaker for me. Honda has greater manual availability than Toyota, they even had a couple of manual hybrids (CRZ, original Insight), proving that "it can be done". VW has manuals across the Golf, Jetta and Passat lines in Canada (except the 6-cyl Passat), and in the 2-wd version of the Tiguan (one of the few SUVs with a manual). In some models and trims they may be hard to find, but they're available.

I'm now TDI-less though my wife still has a '13 wagon. My Golf TSI is also engaging to drive (manual), and has an incredible amount of standard kit for a sub-$21k car (Apple CarPlay/Android Auto, cruise, air, etc. etc.), in fact all the car anyone really needs. So far I've been averaging about 37 mpg (hand-calculated, not MFD).

Agreed that if what one really wants to do is save money, a Yaris or even a low-end Corolla will do that and still get decent enough FE that it will take forever to recoup the cost of a Prius, except maybe a Prius C.

Abacus said:

The TDI turns the fuel off when coasting in gear,

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As does the TSI and the 2.0T and most other gassers these days.

One question stopped my interest in the Prius.

Can I get that in a Manual? No.

That was easy.

Well there is some good news in this analysis:

• Using dyno power as the x-axis normalizes the road load of the Prius and TDI. In effect, it lets us look at engine and drivetrain efficiency measured at the tires on the dyno.
• Prius and Jetta TDI fuel consumption points are plotted. But patterns in scatter charts are not easy to understand.
• Added a 6 degree, polynomial trendline for the Prius and Jetta TDI to get a clue as to the relative fuel consumption under the same dyno loads.
  • Above the idle fuel burn, 0.5 cc/s, and driving the wheels, positive watts, the Prius and Jetta TDI are achieving the same fuel burn rate for the same power. Both metrics are for the automatic transaxle vehicles.
  • Idle fuel burn, less than 0.5 cc/s, and especially slowing, the Prius is able to turn off the gas but the 'defeat device' Jetta TDI continues to burn fuel. This TDI behavior is a VW control law under the control of their software.

If the new VW control software exploits the ability to turn off the injectors when slowing, the fuel savings will significantly improve Jetta TDI highway mileage. It should also reduce the NOx formation assuming it has no adverse, down-stream temperature effects.

So there is hope that the VW fixes announce for January may have a minimal effect on MPG. But we won't really know until the fix is applied. I look forward to comparing the fixed Jetta TDI versus the original.

Bob Wilson

GoFaster said:

Learned something from this ... I didn't know that the Prius had a maximum road speed without engine running. Now that it's mentioned, it makes sense from the way the gearbox is designed.

This might also be why the Volt, which also uses a power split/merge arrangement, has a different mechanical arrangement which has a couple of clutches in there. The Volt has to be able to run all-electric - but to improve powertrain efficiency, it also has to mechanically couple the engine during highway operation once the batteries are run down.

The way the Jetta hybrid works, and for that matter how the various Honda and Hyundai hybrids work and how the old GM and Chrysler "two-mode" hybrids worked, has the single motor/generator between the engine and the transmission with a clutch from the engine so that it can be disengaged, and the motor/generator power runs through the gearbox as usual; the motor/generator runs at engine speed (or the same speed the engine would be running if it weren't de-clutched and shut down). Many newer transmissions (notably the ZF 8-speed rear-drive and 9-speed front-drive transmissions) are designed to allow hybrid integration and this is how all of them do it - the motor/generator takes place of the torque converter and there is a mechanical clutch to the engine. These won't have the "max road speed without engine running" limitation, either.

There are generally many ways of solving a given engineering problem, and there is not always one single clear-cut winner.

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Agreed!

Actually I think the right answer is to put the electric motor/generator on the "layshaft":

• Engine clutch means electric power, "layshaft" can power or manage low power, speed without having the engine on or augmenting as needed.
• Unlike the Honda IMA, the engine clutch isolates the engine so the mechanical overhead does not 'eat' power in EV mode.
• The "layshaft" motor eliminate the weight of a separate engine starter and significantly reduces the 12V battery requirement (and weight.)
• Notice 7.5 kW (~10 hp) to 10 kW is often the EV only range for the Jetta hybrid and Prius. This could be the transmission to marry a TDI/GDI with a hybrid transmission and achieve Toyota challenging MPG.

Bob Wilson

PlaneCrazy said:

As does the TSI and the 2.0T and most other gassers these days.

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Actually, they don't. Not anymore. Many cars use a decel strategy that employs reduced staggered fuel injection events coupled with very retarded timing as well as retarded exhaust camshaft timing where equipped to keep the catalyst(s) at temp. Granted the fuel use during this period isn't all that much, but they don't simply "turn the fuel OFF" like they used to.

Remember, fuel economy and emissions are not one in the same.... unfortunately. If they were, NOx spewing diesels getting 60+ MPG would be at every dealer's showroom floor.

Wankel7 said:

One question stopped my interest in the Prius.
Can I get that in a Manual? No.
That was easy.

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Most Prius owners are at or near driving skill capacity just keeping the car from crashing into others, and many fail at even that. So asking them to also be stewards of their own gear ratio would really be asking too much. I think Toyota knew this from the very beginning.

However, one of the key components to the Prius' hybrid system is the all-planetary CVT. The car simply couldn't do what it does without it, it is integral to the car. Oddly enough, it is a VERY simple transmission at its heart, essentially what a Ford model T used, only instead of varying ratios from high to low with a leather belt, Toyota uses electromagnets. We had them all apart when I was at hybrid school, it is a pretty slick setup. Still sucks to drive.

oilhammer said:

Most Prius owners are at or near driving skill capacity just keeping the car from crashing into others, and many fail at even that.

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Maybe they're too busy reading bar charts and scatter graphs.

At least one Prius driver can drive. Make that two since my wife can drive quite well also.
The transmission on the Prius is a trick and basically keeps the engine at it's most efficient rpm most of the time. It gets louder, but revs up little.
As an electrical guy and engineer I can appreciate the thing for what it is.
Mine was almost dead reliable.
Two repairs really one.
The Inverter electric pump burned up at about 175,000 miles and shortly thereafter the battery lost a cell, but was still drive able.
Total cost less than a DPF repair by far.
Total cost less than 1/2 of that of the VW.
Fun to drive - NO. But then I really don't have fun at work or driving there either.
Driving the old 2009 JSW is more pleasurable than the Prius, but you do pay more for it.

redbarron55 said:

Fun to drive - NO. But then I really don't have fun at work or driving there either.

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That must suck. I'm happy I won't ever have to suffer through life with that burden. I don't have a "job". I have fun with a paycheck.

IndigoBlueWagon said:

Maybe they're too busy reading bar charts and scatter graphs.

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Zing!!

The senseless Sega Genesis looking display in the dash on many of them is quite distracting for some people, too.

redbarron55 said:

At least one Prius driver can drive. Make that two since my wife can drive quite well also.
The transmission on the Prius is a trick and basically keeps the engine at it's most efficient rpm most of the time. It gets louder, but revs up little.
As an electrical guy and engineer I can appreciate the thing for what it is.
Mine was almost dead reliable.
Two repairs really one.
The Inverter electric pump burned up at about 175,000 miles and shortly thereafter the battery lost a cell, but was still drive able.
Total cost less than a DPF repair by far.
Total cost less than 1/2 of that of the VW.
Fun to drive - NO. But then I really don't have fun at work or driving there either.
Driving the old 2009 JSW is more pleasurable than the Prius, but you do pay more for it.

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Glad to see this post. Too many people here with a down their nose view of the Prius owner as less of a person, simply because they own a Prius (or some other driving appliance). Not everyone shares my view that shifting gears or double clutching is a no brain skill everybody should understand/master.

.

I have no problems with Prius owners unless they create one. Kind of a funny video lol.

Upset Prius owner at a diesel truck

I just hate the body style. But, I also hate on other brands as well...(Nissan Juke, Scion's refrigerator box, toaster, brick, whatever you want to call it, the infamous Pontiac Aztec, just a few examples).

I've never driven a Prius before, but the newer Nissan Altima's have the CVT tranny and I think it's better than a regular dog'omatic. Good fuel efficiency too. But after driving a car with a turbo in it, it's hard to go back to a naturally aspirated car.

Abacus said:

That would be a killer for me since we have weeks on end like that. We had a 2 week stretch where it was -20°F every morning and most times we had snow to boot (the old adage "too cold to snow" was disproven many times last year) . It's those times that make me glad I keep my cars running optimally and have an emergency kit on hand (that I have never had to use) since getting stranded can be a death knell.
I have to wonder how the battery packs do in those extremes, I know our Mini-split heat pumps at work don't like it but they're only rated to -15°F anyway.

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Volts keep their battery packs heated in extremely cold temperatures to prevent damage or range problems similar to what the Nissan Leaf has. It is recommended that the Volt stay plugged in when parked to maintain the battery. If it isn't plugged in, it will periodically run the gas engine to maintain battery temperature and charge level.

That's pretty cool. Having no interest in one, I did not know they involved that technology.

My cars don't require me to move past the millennium.

oilhammer said:

Actually, they don't. Not anymore. Many cars use a decel strategy that employs reduced staggered fuel injection events coupled with very retarded timing as well as retarded exhaust camshaft timing where equipped to keep the catalyst(s) at temp. Granted the fuel use during this period isn't all that much, but they don't simply "turn the fuel OFF" like they used to.

Remember, fuel economy and emissions are not one in the same.... unfortunately. If they were, NOx spewing diesels getting 60+ MPG would be at every dealer's showroom floor.

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Is that in the autotragic? My manual TSI (and my past 2.0T) shows 0.0 L/100 km when coasting in gear, so if some fuel is used, it must be a really small amount.

john.jackson9213 said:

Glad to see this post. Too many people here with a down their nose view of the Prius owner as less of a person, simply because they own a Prius (or some other driving appliance). Not everyone shares my view that shifting gears or double clutching is a no brain skill everybody should understand/master.

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Agreed. One thing I really dislike seeing on a car forum is when one group thinks they're product is superior and are entirely close minded about competitors. Every car forum I've belonged to over the past 10+ years this seems to eventually happen. Again, the only reason I drive the TDI is its economy. Otherwise, I wouldn't consider VW. Many gassers have comparable economy to the TDI now.

I have owned other performance cars in the past, including an STi and now own an MK4 Supra. I enjoy driving as much as anybody, but see nothing wrong with a Prius. The Jetta is a beater that's generally cheap to drive and nothing more.

My favorite was an Alfa Romeo Giulietta Sprint Veloce.
It was (of course) equipped with dual twin choke Weber carbs and made a beautiful sound and a pleasure to drive when it was right.





The power of the 1300 cc DOHC engine , while not impressive today, was pretty sporty in it's day. I wish I still had it. This was fun to drive as were the spiders as well. I had several of them through the years as well.





The car had wonderful amenities. For example there was a little light on the dash that lit when the heater was on. That was about the only way you would know.

I had three VW Diesels in the late 70's and early 80's and they were cheap, but not so much fun to drive.

The VW TDI is a very nice road car, but just a car. I have one because it gets good mileage and power. The Prius in 2002 had good economy and I had already had Diesel Rabbits.
I had to twist Connie's are to even try the TDI JSW. She loved it when she test drove it.
Two different cars, two different times.
I would swap the TDI for a nice Alfa SS in a New York second.

The car I always wanted was a 1966 Lotus Elan. Fell in love with it when I first saw it at the Los Angeles Auto Show. Never owned one.

Did find a totally restored one for sale in 1990. Seller had complete photographs and documentation for the restoration. It was a blast to drive. Wanted $25K for it and I knew if I called him back I would mortgage the house to buy that car. Never did call back. He sold the car at Pebble Beach auction for $28K+.

In the past, I had no interest in the Jetta TDI except to address 'fanboy' claims. Then VW admitted they had a "defeat device" in their Jetta TDI software.

Recent 4-wheel dyno and U of WV road tests give a clue about the "defeat device" effects but left out a lot of details. So a Google search led to the Argonne Labs, Downloadable Database, and identical benchmarks for the Prius, Jetta hybrid, and Jetta TDI data. A chance to compare three fuel efficient vehicles, Jetta hybrid, Jetta TDI, and Prius. I enjoy understanding engineering details and had shared these analysis with the Prius community as well here. This thread was really for those who 'can turn a wrench' and curious about things mechanical.

Now I understand fanboy enthusiasm but also know the Donald Trump version of the Golden Rule, 'He who has the Gold, rules.' So here are the recent sales figure where people voted with their wallets before the "defeat device:"

The top line is the Prius hatchback . . . money talks.

Those who share the goal of efficient transportation understand there are more than one way to get there. Since 2012, the EV market more than doubled and a good number of former Prius owners (some of who made their own plug-in) happily switched . . . and hung around to brag on their new rides. Thankfully, a lot of these first generation EVs are being followed with substantially better versions . . . and the former Prius, now EV fanboys have quieted down. Buyers have some choices in what sadly remains a limited number of models. So put a small diesel in a VW MicroBus body and I'll be very interested or if Toyota brings the hybrid Estima to North America. Still, this last bit was for the snarky fanboys.

My understanding is VW plans to release the fixes in January 2016. Probably first applied to the the EPA lab vehicles for PASS/FAIL, then dealer inventory, and later owners. When Argonne gets theirs, I look forward to finding early, new benchmark data at:
http://www.anl.gov/energy-systems/group/downloadable-dynamometer-database

So I look forward to comparing the 2016 Prius and 2016 Jetta TDI for benchmarks:

• US06 - the urban, lead footed driver.
• highway - the long distance cruiser.

Bob Wilson