50% Efficient HCCI Engine

[John_Conrad]

from article:

"What is Nautilus doing differently?

Nautilus CEO Riley has a different idea. Rather than the sophisticated and expensive sensors and direct injection system, Riley is using a single, inexpensive throttle body fuel injector at the entrance to the intake manifold. He claims that this approach ensures that the air and fuel are thoroughly blended into a homogeneous mixture by the time it reaches the cylinder. The real magic is in the cylinder with the piston and combustion chamber design."

http://www.forbes.com/sites/samabuelsami...e/#2ec9608a2a95

 

[yvon_la]

the only reason gas engine dont have the diesel effiency is the fact diesel doesnt burn at high temperature ,gas do. so bottom line lower cylinderand piston to diesel level of flash point and you got your self a winner .

 

[Phishin]

Originally Posted By: yvon_la
the only reason gas engine dont have the diesel effiency is the fact diesel doesnt burn at high temperature ,gas do. so bottom line lower cylinderand piston to diesel level of flash point and you got your self a winner .


English please.

 

[CT8]

I am waiting for the hydrogen revolution to begin.

 

[A_Harman]

This guy hasn't built an engine yet. He only has a plastic 3D printed model. You can make any claim you want until you actually test.

 

[PandaBear]

The control is the key. It would be very very hard to control HCCI engine reliably. They are not the only one working on it. Mazda and GM (and I'm sure every other car company out there) are too.

 

[Schmoe]

cool concept.

 

[HerrStig]

Originally Posted By: yvon_la
the only reason gas engine dont have the diesel effiency is the fact diesel doesnt burn at high temperature ,gas do. so bottom line lower cylinderand piston to diesel level of flash point and you got your self a winner .
Diesels operate at higher compression rations which mean a greater expansion ratio. They also operate without intake restrictions as engine speed is controlled by the amount of fuel injected.

 

[kschachn]

Originally Posted By: CT8
I am waiting for the hydrogen revolution to begin.


Sure thing, once that pipeline to the sun is built.

Other than that happening, there's an enormous thermodynamic hill in the way.

 

[Shannow]

I think the inclusion of a "fire piston" is novel, but only one step off having a hot tube like many engines of yore used to...and they weren't renowned as being overly energy efficient.

I just cannot see how that translates into 50% thermal efficiency...it's still limited to S.I. engine compression ratios.

 

[Ducked]

Originally Posted By: Shannow
I think the inclusion of a "fire piston" is novel, but only one step off having a hot tube like many engines of yore used to...and they weren't renowned as being overly energy efficient.


Efficiency isn't everything. There's the sound as well.

Long ago on a motorcycle forum far far away, people were saying how much they loved the sound of a "hot 2-stroke"

I agreed and posted this. Apparently it isn't what they had in mind??

 

[Mitch Alsup]

It has been reported that the 2016 F1 engines are operating at 54% thermal efficiency.

A good deal of this is the Turbo Motor generator absorbing energy from the exhaust stream to avoid over-boosting the engine sending the power to the transmission motor-generator.
Also, the tranny-MGU recovers a lot of braking energy that is then used to accelerate out of turns.
Occasionally, the Turbo MGU adds energy to the incoming air to avoid turbo-boost lag.

 

[weasley]

It was also mentioned in commentary at the Chinese GP that some engines are operating in a HCCI mode under certain load/throttle conditions - if I heard and remember right it is during a trailing throttle scenario.

Remember though that the large, 2-stroke, crosshead diesel engines used in the biggest ships achieve >50% thermal efficiency when employing power take-in and other exhaust energy recovery systems. And that's burning residual fuel oil.

 

[Mitch Alsup]

Originally Posted By: weasley
And that's burning residual fuel oil.


Which has greater thermal energy per weight than the gasoline stuff.

 

[Shannow]

Originally Posted By: Mitch Alsup
Originally Posted By: weasley
And that's burning residual fuel oil.


Which has greater thermal energy per weight than the gasoline stuff.


that doesn't alter the thermal efficiency.

Thermal efficiency is energyout/energyin.

 

[Garak]

Originally Posted By: weasley
It was also mentioned in commentary at the Chinese GP that some engines are operating in a HCCI mode under certain load/throttle conditions - if I heard and remember right it is during a trailing throttle scenario.

Yes, you heard that correctly.

 

[A_Harman]

Originally Posted By: Garak
Originally Posted By: weasley
It was also mentioned in commentary at the Chinese GP that some engines are operating in a HCCI mode under certain load/throttle conditions - if I heard and remember right it is during a trailing throttle scenario.

Yes, you heard that correctly.


I doubt it's true, though. On trailing throttle, why even inject fuel?

 

[JHZR2]

Originally Posted By: Mitch Alsup
It has been reported that the 2016 F1 engines are operating at 54% thermal efficiency.

A good deal of this is the Turbo Motor generator absorbing energy from the exhaust stream to avoid over-boosting the engine sending the power to the transmission motor-generator.
Also, the tranny-MGU recovers a lot of braking energy that is then used to accelerate out of turns.
Occasionally, the Turbo MGU adds energy to the incoming air to avoid turbo-boost lag.


Probably also that every last bit of longevity margin is removed as any non-failing item at the end of the race season is lost milliseconds...

 

[Garak]

Originally Posted By: A_Harman
I doubt it's true, though. On trailing throttle, why even inject fuel?

That did cross my mind; after all, what you mention is the way it's done in passenger vehicles all over. With F1, there could be a very sound engineering reason. Or, it could just as likely (or more likely) be some bizarre rule about requiring fuel flow to never be cut off while a vehicle is racing or in motion or whatever more bizarre wording they would have qualifying that.

Or, some engineer fed a commentator a line, but in my feed, I'm pretty sure Martin Brundle confirmed it.

 

[Mitch Alsup]

A) braking events are very short
B) you still need the turbo spooled up after the braking interval.