Toyota's approach to improving ICE efficiency

[cRiPpLe_rOoStEr]

Originally Posted by serialk11r

What is really interesting is that Toyota is sticking with relatively large displacement NA when Honda is committing to small turbo engines.

Considering that so many international markets apply some displacement-based taxes, it makes sense that Honda would focus on the downsizing. When it comes to Toyota, it seems like they're looking forward into benefits for hybrids regardless of displacement.

[redpoint5]

Originally Posted by sendler

Mercedes is achieving 181 hp/ Liter with maximum pulse boost pressures of 1.8 bar/ 26 psi. With flat torque of 450nm/ 332 ftlb from 2250-5000. In a family car.

OK, that's probably impressive, but what MPG can it achieve under low loads considering an 8:1 compression ratio?

My 16 year old motorcycle puts out 200 hp/liter with no turbo. I'm getting 47 MPG with all that power to weight.

I don't get the appeal of powerful sedans. It's pointless in that a sedan is a practical vehicle, made uselessly fast and expensive. I'm getting older, and perhaps riding motorcycles has ruined my expectations for affordable fun.

[sendler]

8:1 is an error. 9.8:1 is reported. And, that is only at idle. variable vane turbos crank up pressure quickly at low rpm's.
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https://www.edmunds.com/mercedes-ben...st-specs1.html
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[cRiPpLe_rOoStEr]

Originally Posted by redpoint5

I don't get the appeal of powerful sedans. It's pointless in that a sedan is a practical vehicle, made uselessly fast and expensive. I'm getting older, and perhaps riding motorcycles has ruined my expectations for affordable fun.

At least in a sedan you could carry more "witnesses" than in a 2-seater roadster

[Ecky]

To my knowledge, Honda hit approximately 40% thermal efficiency (give or take) with the G1 Insight's engine back in 1999, without the Atkinson cycle, and slightly surpassed it with the 2L i4 in the 2nd gen Accord Hybrid. Honda cited many of the same technologies back in 1999. Makes me wonder why it has taken so long to make it into more mainstream engines.

[Fingie]

Originally Posted by Ecky

Makes me wonder why it has taken so long to make it into more mainstream engines.

Customers warm up slowly, and maybe manufacturers did not see a need to implement the technology, saving costs.

[wdb]

I've done turbos and I've done NA. At the moment my heart -- and money -- is in the NA camp. The Toyota technology sounds promising. I drive two of their v6 engines currently; one is the seriously understressed 4.0 in my Tacoma pickup, the other is a more highly refined 3.5L that makes impressive power and torque when required, and surprisingly decent gas mileage the rest of the time. I'm eager to see this new tech in a Toyota v6.

[cRiPpLe_rOoStEr]

Originally Posted by wdb

I've done turbos and I've done NA. At the moment my heart -- and money -- is in the NA camp.

Even though I don't believe NA to have become obsolete at all, mostly due to the cost too, I've been more favorable to forced induction.

[wdb]

Originally Posted by Old Tele man

If you follow the technological progression of aircraft reciprocating engines, they started as NA and ended as 2-speed Super-charged Turbo-Compound (R3350).

Different application. Aircraft engines are almost steady state. Although with the way traffic levels are growing...

[cRiPpLe_rOoStEr]

Originally Posted by Old Tele man

If you follow the technological progression of aircraft reciprocating engines, they started as NA and ended as 2-speed Super-charged Turbo-Compound (R3350).

The majority of the piston engines for aircraft in use nowadays are quite outdated, and mostly NA. Just recently with the introduction of modern turbodiesels to light aircraft that turbocharging is catching up again. In this case, the cost of certification and liability is what has driven the general aviation market to retain some rather outdated tech.