Print 65 comment(s) - last by superstition.. on Oct 19 at 12:54 AM

Larger displacement Atkinson cycle engines may be in the future for Toyota

A number of automotive manufacturers have begun to move away from larger displacement naturally aspirated engines to smaller displacement turbocharged engines. The general idea was that smaller and lighter engines would use less fuel while offering the same sort of performance thanks to the addition of a turbocharger. However, in the real world many drivers have discovered that turbocharged small displacement engines are often unable to deliver on their fuel efficiency claims.

Toyota is considering bucking the industry trend and rather than going with smaller turbocharged engines, is considering larger naturally aspirated engines to improve fuel efficiency. Senior managing officer in charge of drivetrain R&D for Toyota Koei Saga recently said that Toyota believes gasoline engines could benefit more from upsizing capacity in conjunction with Atkinson combustion cycles than going smaller with turbochargers.
Atkinson engines today are typically only used in hybrid vehicles like the Prius, Ford Fusion Hybrid, Hyundai Sonata Hybrid, and Honda Accord Hybrid.

Toyota Camry
Increasing the displacement of an engine using the Atkinson cycle would deliver a specific output less than that of similarly sized conventional combustion cycle engines, but fuel economy would be better. Toyota believes that fuel economy would be better than the smaller engines they replace.
Toyota has offered no timeframe for bringing larger displacement Atkinson cycle engines to market and hasn't hinted at which models might get the Atkinson cycle engines.
Mazda experimented with similar “delayed valve” Miller Cycle technology over a decade ago in the Millenia midsize sedan. But instead of using electric motors to make up for the reduced power density like today’s Atkinson-engine hybrid vehicles, the Millenia used a supercharger.
Saga also talked a bit about the next generation Toyota Prius saying that the vehicle will use a mixture of battery technology including lithium-ion and nickel batteries. The reason for mixing battery types is that lithium-ion batteries are better for performance, but the durability and lifespan is better for nickel batteries. 

Source: Green Car Reports

Comments     Threshold

This article is over a month old, voting and posting comments is disabled

RE: According to whom?
By Brandon Hill on 10/16/2013 10:11:52 AM , Rating: 2
The part you quoted links to a Consumer Reports article (they're also the ones the called out Ford on the optimistic C-Max Hybrid fuel economy numbers before they were revised).

In the real world, I have the feeling that many people are probably applying a bit too much "go" to get these smaller four-bangers moving and therefore hitting the boost more.

And I also have to question the move to these smaller, turbo engines as opposed to larger, normally aspirated models. The 1.6 in the Fusion doesn't even manage to get better power or fuel economy than the larger NA fours in the Altima and Mazda6.

RE: According to whom?
By Pneumothorax on 10/16/2013 10:15:57 AM , Rating: 2
Not only do I agree on questioning the transition to these tiny turbos, but a larger displacement NA engine is going to be much more reliable in the long run as it won't have the typical issues of these small turbos such as intake carbon build up and turbo failures.

RE: According to whom?
By Brandon Hill on 10/16/2013 10:24:12 AM , Rating: 3
Yup. The Honda Civic HF gets the same combined fuel economy as Fit's old Cruze Eco, and does it without turbocharging or direct injection.

When it comes to powertrains, I put a lot of stock in GM's engines... However, a turbo Cruze vs a NA Civic is a no-brainer as far as engine reliability/running costs over the life of the vehicle.

RE: According to whom?
By Spuke on 10/16/2013 12:18:35 PM , Rating: 2
I'm driving a 2007 Pontiac Solstice GXP with a 2.0L turbo DI engine. 19/28 are the EPA figures and I get 28 mpg (last few weeks getting 29). Too much boost will lower your fuel economy. If I keep my boost at 5 psi or lower I get 33 mpg but that's no fun. I fully believe it's driving style killing mileage not car capability.

RE: According to whom?
By dgingerich on 10/16/2013 12:40:04 PM , Rating: 3
You're right about driving style killing mileage, but also the driving styles of the testers are inflating the numbers. I'd bet the numbers some of these car companies are putting out are done with a driving style that would have people merging onto a highway doing 35-40.

RE: According to whom?
By fic2 on 10/16/2013 1:04:28 PM , Rating: 2
You mean like people around here normally do? Freaking kills me that most people don't know to accelerate on that long strip of asphalt before they hit traffic.

RE: According to whom?
By dgingerich on 10/16/2013 2:04:02 PM , Rating: 2
Yeah, I've lived in 4 different major metro areas, and I've seen that in every one, but a little more pronounced in certain areas of Chicago. (NW suburbs of Chicago are DANGEROUS. you have a mix of super aggressive, from downtown, and super passive people, from the local area. Getting caught between them is a really bad idea.) Stupid is everywhere.

I recently saw an old woman in the Denver Tech area in the evening rush hour merge onto I-25 doing about 40, and move over two lanes at once. It caused a 7 car accident across those two lanes from the people who had to slam on their brakes to avoid her, and she didn't even seem to notice the chaos and damage she unleashed. Luckily, I was in the third lane over and missed it all, and managed to pass her. She didn't even signal in any of her lane changes and moved all the way over to the left lane, doing 55 in a 65 zone, causing all sorts of traffic problems behind her, all in the less than 3 miles I watched her until I got off the highway.

A lot of the people I talk to who drive that way think it's safer, clueless of what they unleash on other people. I've tried explaining it, and they just come back with "those other people shouldn't be going that fast anyway." It's the Dunning-Kruger effect in its full glory.

RE: According to whom?
By Philippine Mango on 10/17/2013 6:40:51 PM , Rating: 2
Your story about the old woman driving reminded me of this video:

RE: According to whom?
By Jeffk464 on 10/16/2013 5:18:20 PM , Rating: 2
No you accelerate faster when you need to like getting on the freeway and mellow out when its not necessary. Watch most people on the freeway, when a car moves out of the lane in front of them they gun it immediately to fill in the gap.

RE: According to whom?
By Mint on 10/16/2013 4:20:00 PM , Rating: 2
Slow acceleration doesn't help efficiency much.

If you ever look at an engine's BSFC chart, they're most efficient at ~80% throttle (low RPM, of course). Even for small engines, there's enough power there to avoid "merging onto a highway doing 35-40".

The biggest style factors on efficiency is speed (due to air resistance) and number of acceleration-deceleration cycles (especially with non-hybrids). The latter usually goes up with lead-foots, tailgaters, and pathological lane-changers even when they obey speed limits.

The other factor, of course, is your route. Lots of stop signs make your fuel efficiency tank. The EPA city test is representative for a lot of people, but not everyone. I only average 10-15 mph when off the highway due to traffic, stop signs, and lights.

RE: According to whom?
By Reclaimer77 on 10/17/2013 4:19:07 PM , Rating: 2
One thing I hate about new drive-by-wire throttle systems is that it's almost impossible to gauge your throttle position, due to electronic trickery. You might only be using 30% of the pedal, but the engine is electronically advanced to 60%. Think you're only using 50% throttle under acceleration? Wrong, you're using like 80%!

I get why they do it, it makes the car feel faster and quicker at all times, because it's always using more throttle than your foot is applying.

RE: According to whom?
By superstition on 10/19/2013 12:51:44 AM , Rating: 2
Is this true for current diesel cars? My Passat TDI 6 speed "automated manual" (in automated mode) seems to get much better mileage (according to the computer) when I accelerate leisurely.

RE: According to whom?
By BikeDude on 10/17/2013 5:51:16 AM , Rating: 2
Make sure you compare apples to apples.

If you choose a V6 NA over an inline 4-cylinder turbocharged engine, you might get the same performance, but...

Make sure the larger engine is still maintainable. A colleague of mine was charged an excessive amount of money to replace a simple thermostat on his VW Passat (w/V6). It is so difficult to gain access to the thermostat so what should be a simple procedure becomes a very complex operation. Unless you enjoy doing such jobs yourself, you might not be saving the kind of money you think you are.

I've replaced the thermostat on my Saab 9000 2.3T myself. It is a much faster car than my colleague's VW and the thermostat was easily replaced.

The turbo isn't that hard to replace either. I got my dad a second hand low-mileage turbo for $200. Still less than what my colleague paid for that thermostat.

As for fuel economy: Yes, the faster you get up to speed, the sooner you run the risk of having to slow down. Every press of the boring brake pedal means a loss of energy, so faster will always be more expensive. However: I have the choice every time I ride my car. And I can accelerate out of potentially dangerous situations.

RE: According to whom?
By hpglow on 10/16/2013 11:55:51 AM , Rating: 2
My 2000 VW Jetta TDI just flipped 200k miles a month agao. That is with it pushing 24lbs boost up over the stock 17lbs for the last 100k miles. A well designed turbo engine is just as reliable if not over-built compared to its NA counterpart. The last GM car I bought seized after 140k miles. All my vehicles get their proper maintenance. Modern turbos aren't like the turbos of the past they are far more durable.

RE: According to whom?
By bobsmith1492 on 10/16/2013 12:18:32 PM , Rating: 2
And the turbo in my brother's 04 Jetta TDI died with around 100K miles just after he bought it. Point is a sample size of 1 is not very informative.

RE: According to whom?
By Devilboy1313 on 10/16/2013 3:35:41 PM , Rating: 2
If it died just after he bought it I see the problem. The last owner knew there was something wrong and wanted to pass on the problem to somebody who may not have taken it to a professional to be checked.

Min sample size should always be a diverse 50+.

RE: According to whom?
By Jeffk464 on 10/16/2013 5:21:22 PM , Rating: 2
its a bummer and expensive to fix on an old car. You can always open up the turbo and take out all the insides and put it back in. The car will run fine you just loose a lot of power.

RE: According to whom?
By Heidfirst on 10/16/2013 5:15:34 PM , Rating: 2
except that your 2000 VW isn't a modern turbodiesel ...
Modern turbodiesels have very high pressure common rail injection, DPFs, DMFs etc.. They may be more durable but they are less reliable because they are more complicated.;) & when the common failures occur in the UK you are typically looking at $1500 fixes.

RE: According to whom?
By superstition on 10/19/2013 12:54:41 AM , Rating: 2
That's nothing compared to the timing chain replacement with gears cost for the B5 Passat or the fuel system failure problem due to metal shards with the more recent CR VW diesels.

Bosch and the EMA in general warned, at least as early as 2008, that the lubricity of US diesel will cause premature wear. Their designs were not made for anything about 460.

RE: According to whom?
By FITCamaro on 10/16/2013 10:26:54 AM , Rating: 2
I have a 2013 Altima SV now and yes the fuel economy is quite good. I average 38 on the freeway as advertised and average around 35 in my daily commute.

I really like the way the fusion looks but yeah the fuel economy wasn't as good. I think that's because of weight though.

The Altima is 3182-3230 lbs for the 2.5L models.
The Fusion is around 3615 lbs. They don't have individual curb weights listed for particular models.

RE: According to whom?
By Brandon Hill on 10/16/2013 10:31:33 AM , Rating: 2
I hope I'm not getting you mixed up with Reclaimer (I think that he's the Subaru nut), but you seem to have gone through a lot of cars in the past few years ;)

IIRC, you've had a Cobalt SS, a GTO, the Cruze, and now an Altima in the span of maybe 3 or 4 years?

RE: According to whom?
By Monkey's Uncle on 10/16/2013 11:18:55 AM , Rating: 2
Perhaps he works in a car dealer?

RE: According to whom?
By SilthDraeth on 10/16/2013 11:33:24 AM , Rating: 2
"In a car dealer"


RE: According to whom?
By syslog2000 on 10/16/2013 11:54:49 AM , Rating: 2
Lol! Busted! Fitcamaro, you better have a good excuse ;)

RE: According to whom?
By Brandon Hill on 10/16/2013 12:02:57 PM , Rating: 2
I wasn't trying to "bust" him. As a car guy, I just notice things like that when they are mentioned.

RE: According to whom?
By FITCamaro on 10/16/2013 1:33:40 PM , Rating: 2
In 8 years I've had 4 cars:

2005-2008 Cobalt SS 2.4L 5M
2008-2012 GTO 6M
2012-2013 Cruze Eco 6M
2013 Altima

Cruze was only replaced because of a semi backing into it.

RE: According to whom?
By Brandon Hill on 10/16/2013 1:39:55 PM , Rating: 2
OK, I got ya. I caught on at the tail end of your Cobalt days and then the mishap with the semi skewed things a bit.

Sorry to hear about your Cruze though :(

RE: According to whom?
By FITCamaro on 10/16/2013 2:52:12 PM , Rating: 2
I've been on this site since 2002 I think when I had an 87 IROC. Then was an 89 Camaro RS/Z28 clone with nothing stock.

RE: According to whom?
By Jeffk464 on 10/16/2013 5:24:25 PM , Rating: 2
replaced because of a semi backing into it

Yeah, thats pretty easy to do.

RE: According to whom?
By Reclaimer77 on 10/16/2013 1:44:57 PM , Rating: 2
Sorry Brandon I can barely hear you out here, bad signal. I'm still in line at the dealership personally reserving my spot for the first BRZ STI in my area!!

If you see my girlfriend, tell her I love her, and there's a spot for her in my tent. Also I'm pretty hungry...

RE: According to whom?
By Brandon Hill on 10/16/2013 1:49:03 PM , Rating: 2
You're hungry? I'll get you a full plate of torque. You're gonna need it ;)

Seriously though, congrats!

RE: According to whom?
By Spuke on 10/16/2013 7:52:09 PM , Rating: 2
BRZ STI??? I needs to do some internets searching!

RE: According to whom?
By Brandon Hill on 10/16/2013 10:10:14 PM , Rating: 2
It's not what you think though (no turbo); it's more of a handling package AFAIK:

RE: According to whom?
By Reclaimer77 on 10/17/2013 1:39:26 AM , Rating: 2
Nope. It's already been confirmed. Big power increases.

Come on, you actually believed something would be badged "STI" and NOT be boosted? Tisk tisk :P

RE: According to whom?
By Spuke on 10/17/2013 3:51:12 PM , Rating: 2
I don't know Rec. Seems to be quite a bit of confusion on the BRZ STi still. Can't seem to get a straight answer anywhere. Guess it's just a wait and see. Even if it does exist, I need to see lap times. Tired of buying overly compromised "sports" cars.

RE: According to whom?
By cruisin3style on 10/16/2013 8:12:13 PM , Rating: 3
FIT is right, people rating him down just don't know how to drive other than: "if i'm not on the g0dd4mn brake, i'm on the f#@king gas b!tch!"

it is because most people drive automatics, and may never have touched a stick in their life. you can decelerate by letting off the gas! you don't have to speed up until you have to brake!

one thing i see all the time that is a total waste of gas is people accelerating towards a red light, and none of the lanes are empty (in case the red light turns green before they get to it and they can then just cruise through). People even pass me when i'm engine braking toward a red light, even though the red light is coming up very soon, and like i said there is nowhere to go.

i picked up a used mazdaspeed3 recently that is rated something like 18 city/25 highway but 25 is the worst i've gotten and low 30s is the highest. and i do plenty of city driving, at least 1/3 of my driving is city, and i do not drive like an old lady.

you just have to know how not to drive like a cock.

RE: According to whom?
By Spuke on 10/17/2013 3:58:57 PM , Rating: 2
one thing i see all the time that is a total waste of gas is people accelerating towards a red light
I thought I was the only one that noticed that. I see this crap ALL of the time. And what's up with the continuous acceleration between two points? There's a long stretch of road on my commute that starts at a stop sign and goes past a freeway entrance (about 6 miles). Most people turn onto the freeway. At LEAST 90% of the people I follow on this stretch accelerate the ENTIRE section, hitting their fastest speed on the last 1/3, then slow for the onramp. WTF is that?! No wonder most people can't match EPA mpg ratings.

RE: According to whom?
By Philippine Mango on 10/17/2013 6:49:33 PM , Rating: 2
Yeah I drive a 2007 ES350 and I average 26-28mpg with 50-50 city highway driving but then again I'm pretty light on the throttle and I try to get into the highest gear as quickly as possible and maintain speeds that keep the car in a higher gear with the torque converter locked up.

RE: According to whom?
By Samus on 10/16/2013 9:34:42 PM , Rating: 2
There is definitely a particular way to drive a turbo engine, just like there is a diesel.

Anybody jumping in a turbo I4 and driving it like a V8 is going to be disappointed in a lot of ways other than poor fuel economy. Boost = efficiency. Boost is attained at higher RPM's. You can't just keep the machine bogged down driving in the city, you need to have some fun with it which will actually result in improved MPG.

RE: According to whom?
By Reclaimer77 on 10/16/2013 9:48:33 PM , Rating: 2
you need to have some fun with it which will actually result in improved MPG.

LOL that hasn't been my experience with turbo 4's :)

However I concede that my car isn't tuned for economy. Just the way I like it.

"If a man really wants to make a million dollars, the best way would be to start his own religion." -- Scientology founder L. Ron. Hubbard

Copyright 2016 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki