I don’t know about that, it’s a pretty major change in valve timing. If it was easily done with VVT I imagine they’d be doing it. Unless you believe the engine designers are either idiots or scheming to keep technology away from us, even though they’re under huge pressure to find every mpg possible. I don’t buy the ‘conspiracy theory’ angle for a second.
There may, or may not be a good reason, but it would sure be nice to know why it cant be done.
I think the engine used in the Yaris does go Atkinson cycle during idle and low throttle use with its VVTi. It’s just not as extreme as the engine used in the Prius and has a lower compression ratio to allow it to go full Otto cycle at full throttle, allowing it to make a claimed 105 hp verses the Prius engine’s claimed 70 hp. The Prius engine with its super high 14:1 CR is always in a varying stage of Atkinson cycle, it would have to burn methanol in order to go full Otto cycle with that compression ratio.
My manual 5 speed Yaris is one of the trickiest cars I have ever owned to engage the clutch on, too much engagement and the engine wants to die, too little and it races to the moon. I blame this on running in the Atkinson mode during idle. However, when the engine is first started and the cool engine light is still on, it clutches very easy like a normal otto cycle engine. I think the engine defaults to otto when cold because the higher intake vacuum lowers the boiling point of gasoline and makes it warm up faster with a less enriched fuel mixture.
People with Scanguage II engine monitors also report that this car has a remarkably low .157 gallon per hour idle fuel consumption.
The Prius engine makes a claimed 98hp only 7hp less then the Yaris. A 138HP combined with electric motor according to Wiki
“My suspicion is a conventional non hybrid car that uses all the fuel saving tricks as a hybrid such as aerodynamics low rolling resistance tires Atkinson cycle VVT engine etc… could get the same highway gas mileage if not more as a non plug in hybrid such as the current Prius. Maybe the hybrid would better its city mileage with possible 5 mileage better fuel mileage overall.”
Well, the three obvious tricks a hybrid has up its sleeve are: 1) Turns off the ICE during low demand, instead of idling 2) Re-captures some (not all) of the kinetic energy usually lost to heat via mechanical braking 3) Undersized ICE realizing better HP-specific fuel consumption.
If you look at all the tricks involved with hypermiling, though, many of the most productive ones are designed to get a “non-hybrid” car to mimic a hybrid in operations (stuff like coasting, turning car off at lights, trying to brake as little as possible, etc.) You could say that a hybrid car is just a car designed to make certain hypermiling behaviors “default.”
Also: seeing as most of the technological/economic/public acceptance issues re: e-cars revolves around battery technology and range, what about “third rails”? (Or trolly-car cables, or what have you.) You could stil have a (smaller, cheaper) battery on board for areas the “urban electrification project” has yet to reach. Granted, working out a payment scheme would be a problem, but not an insurmountable one. Also, this truly constitutes “proven technology.”
So why is this not “on the table?”
…The Prius engine makes a claimed 98hp only 7hp less then the Yaris…
I was probably thinking of the first generation Prius which had basically the same 1.5 liter engine used in the Yaris but tuned to make only 70 hp.
Second generation Prius had a 76 hp engine.
The current third generation Prius has a 1.8 liter engine and 98 hp as you stated.
Just like with all the other car models, size creep seems to be setting in until it becomes something nearly unrecognizable to a first generation Prius owner, just like the Honda Civic has darn near grown into a full size car.
though not a hybrid owner, I believe you have missed a major real world difference. many of the los angeles “parking lot” freeway drivers receive hybrid benefits because they efficiently curtail the internal combustion use while racking up few miles (short stop and go provided by battery). A regular IC corolla engine is running all the time.
You might want the look at these “Shared MPG Estimates”
https://www.fueleconomy.gov/mpg/MPG.do?action=browseList2&make=Honda&model=Civic Hybrid < You have to cut-n-paste this one
https://www.fueleconomy.gov/mpg/MPG.do?action=mpgData&vehicleID=25921&browser=true&details=on
https://www.fueleconomy.gov/mpg/MPG.do?action=browseList2&make=Toyota&model=Prius
https://www.fueleconomy.gov/mpg/MPG.do?action=mpgData&vehicleID=30919&browser=true&details=on
https://www.fueleconomy.gov/mpg/MPG.do?action=mpgData&vehicleID=26425&browser=true&details=on
Even small diesels reflect some interesting “user experience” numbers relative to “sticker”
https://www.fueleconomy.gov/mpg/MPG.do?action=browseList2&make=Volkswagen&model=Jetta
Hope this adds to the discussion.
Another factor to throw in the spreadsheet. Figure gas at $4 for this year, $5 next year, maybe $8 the year after.
I agree that hybrid isn’t a winner for highway driving, and Toyota could put out a Prius-light that has every efficiency feature except the hybrid that would do pretty well.
Forget the hybrids! My brother just sent me an ad for an accessory on an automobile that will give you one free mile for every 4 miles that you drive. This should result in a 25% savings.
The device is the free-wheeling automatic overdrive and the car is a 1941 Packard. “Ask the man who owns one” and see if I’m right. Of course, you may have some problem locating a 1941 Packard and an even harder problem locating an original owner.
“Another factor to throw in the spreadsheet. Figure gas at $4 for this year, $5 next year, maybe $8 the year after.”
So you’re suggesting he predict the future?
To me, the most ludicrous thing in the world to do would be to invest in a new car–of ANY kind.
I work in a courier business, making deliveries. I drive typically 40-50,000 per year, every year. My vehicles have been minivans for the most part, such as the '91 Chevy Lumina I had last time around, although my current car is an '02 Ford Taurus Wagon.
I’ve opted for V-6 engines almost always–the best compromise to get the needed power to keep me safe on the road without going overboard in gas consumption. Typically, I average about 20-22 MPG long term.
I spend about 8,000/year on gas and about an equal figure on repairs every year. The vehicles last an average of two years and figure the purchase price at about 3,000 to 3,500, again typical. My insurance is 1,600 and change annually, including the legally required basics for a vehicle with a loan, plus Comprehensive and a touch extra on liability coverage. My note is currently 100 every two weeks.
Frankly, if I had the kind of money you’d need to invest in a brand new car, I’d buy an old '72 Nova with a small V-8, spend a couple thousand on rebuilding the engine right down to the rings and cams, ditto on the tranny, do a complete restoration on the body, then take the money I saved and invest in a mutual fund.
“Friends don’t let friends drive riceburners…”
You have to borrow money to put together $3,000, which increases your insurance cost, (collision insurance? does the insurance company know this van is used as a commercial vehicle?) and you spend $8,000 on repairs annually. So you’ve got $11,000 of unrecoverable capital expenditures. $19,000 over the two year lifetime of the van. I’m not sure I’d go around telling people that.
“Friends don’t let friends drive riceburners…”
To each his own, I guess…
Rice is pretty darn expensive to use as auto fuel, I’ll stick with gasoline fueled cars.