Toyota's approach to improving ICE efficiency

[Frank Lee]

Toyota

"Dynamic Force" tech gets them to 40% thermal efficiency?!?

[Stubby79]

Very nice!

[cRiPpLe_rOoStEr]

Toyota's strategy is quite interesting, even though at a first sight that engine could be initially pointed out as "outdated" due to the absence of a turbo. But it's still surprising how far the ICE can be improved before resorting to the expenses of forced induction (even though I actually like the altitude compensation provided by a turbo).

[cRiPpLe_rOoStEr]

Originally Posted by Old Tele man

Benefit of a turbo: IF computer is smart enough, the engine can, in real-time, handle basically any grade of suitable fuel as well as altitude...producing essentially a horizontally-constant "flat" torque curve.

It works more effectively with direct injection for the matter of handling different grades of suitable fuel, but that Toyota engine has a dual-injection setup so it might eventually be capable to do so too.

[Frank Lee]

Originally Posted by Old Tele man

So, Toyota is gonna re-invent the Hemi-head swirling airflow ease and call it 'Dynamic Force'?

There must be more to it. Do other hemis have 40% efficiency?

[ar5boosted]

Originally Posted by Old Tele man

I was alluding to the fact that with the engine computer controlling the turbo waste-gate dumping of 'excess' air pressure, the engine effectively becomes a quasi-variable compression ratio device, and where "suitable grade" meant the octane value of different fuels.

Nissan are about to release the MR20DDT Variable compression engine soon:

https://www.youtube.com/watch?v=hSEUBWVfarQ

You're correct. All modern turbo engines use computer controlled wastegates rather than vacuum controlled wastegates to manage boost. It gives small engines more torque at low speeds because they close the wastegate and go to boost when taking off. Rather than waiting for vacuum to finish before closing the wastegate. That's most of the secret to the modern turbo engine.

Toyota are also following along with their C-HR having a 1.2T.

[redpoint5]

40% is a fantastic peak efficiency. What will the average efficiency end up being?

What is the average efficiency of a typical engine?

[cRiPpLe_rOoStEr]

Originally Posted by Old Tele man

I was alluding to the fact that with the engine computer controlling the turbo waste-gate dumping of 'excess' air pressure, the engine effectively becomes a quasi-variable compression ratio device, and where "suitable grade" meant the octane value of different fuels.

Indeed. But anyway, direct injection does increase the ability of an engine to avoid knocking while using lower-octane fuel with higher compression.

[sendler]

Direct injection is still expensive but is a huge step forward when paired with turbos since there is no fuel in the combustion chamber to pre ignite. And it is even possible to utilize multiple injections per firing cycle to get the exact stratified mixture and pressure profile all throughout the piston excursion. But it is expensive, complex, and noisy. 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.
.
Mercedes A 45 AMG: The most powerful 4-cylinder turbo engine in the world
.

[serialk11r]

I'm pretty sure most of these gains come from cooled EGR. The electric water pump would only help a little, and the rest of the engine is unremarkable compared to the 2AR predecessor. Direct injection and high compression only adds a small bit.

It really just goes to show that older engines were just really held back for cost reasons.

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