Honda patents engine with different cylinder dis.

[HTSS_TR]

Quote:
A basic rule of engine design states that the displacement of a cylinder is equal to the engine's total displacement divided by its cylinder count. Honda, according to a recently surfaced Japanese patent, is looking to break that rule with an engine containing cylinders of different sizes. We've done our best to translate it from patent-ese.


Quote:
The idea is that different-sized combustion chambers give more flexibility when any combination of cylinders are deactivated, or rested. Because the different numbers can be combined in various ways, it provides more and smaller increments than would an engine with equal-displacement cylinders. Take a 2.0-liter four-cylinder, for example. Following the golden displacement rule, each of the four cylinders has a volume of 500 cc, giving displacement increments of 500 cc when any cylinder is deactivated. But suppose instead that the four cylinders displace 300, 425, 600, and 675 cc, respectively. This would give the engine 15 available displacements instead of just four, and the spacing between each option would be far less than 500cc.


http://www.foxnews.com/leisure/2016/05/0...-displacements/

If this can be implemented correctly it can improve gas mileage better than current variable displacement employed.

 

[AZjeff]

Would love to see a computer generated model of the loading/harmonics of the crank.

 

[OVERKILL]

Given the issues Honda has already had with 'regular" MDS, I shudder to think of how many ways this could go wrong

 

[Kawiguy454]

^ +1 ...just because we can make a plane with wings that point forward fly doesn't mean we should do it for everyday usage. Whatever happened to the Oval cylinder Honda engine?

Kawasaki heavy industries has created a supercharged motorcycle engine 1000 CC's that can make >300HP. They have also shown development renderings of an aperture device that could control the boost. Sounds like a much better way to make a small engine with wide performance curve.

 

[Cujet]

Not a novel idea. I'm surprised they were able to patent it.

I do have to wonder about the potential savings. I rented a Seat Leon with a direct injection, 1.2L, 4 cyl engine. It ran on 2 cylinders occasionally. But, as expected, 2 cylinder mode was rather incapable of doing useful work.

I was impressed with the overall capability of the engine, with full boost just above idle, a wide torque curve and 42MPG overall.

However, it seems the Prius and it's engine with 40% thermal efficiency and hybrid drive is a more effective way to maximize economy.

 

[HTSS_TR]

I think with computing power of the current and future ECU a good software can control/activate individual or a combination of cylinders much more precise than the old method. But this application still have a long way to go before it can be actually be used in production engines.

Yes, whatever happened to the oval cylinder that Honda talked about some years ago ? Probably didn't do very good in their test(s).

Sometimes it looks like a good idea, but implementing it and test it in a lab or in real world didn't turn out as good as first thought.

 

[demarpaint]

Originally Posted By: OVERKILL
Given the issues Honda has already had with 'regular" MDS, I shudder to think of how many ways this could go wrong

Me too. I'll let someone else be an early adopter, test it, and report about it, if it comes to be.

 

[artificialist]

Originally Posted By: HTSS_TR

Yes, whatever happened to the oval cylinder that Honda talked about some years ago ? Probably didn't do very good in their test(s).


From what I read, the performance of the oval shaped piston rings was the biggest problem. I hope that didn't discourage other people from trying to make oval engine cylinders using technology that didn't exist way back then.

 

[hpb]

Originally Posted By: HTSS_TR
Yes, whatever happened to the oval cylinder that Honda talked about some years ago ? Probably didn't do very good in their test(s).


Honda built and raced V4 oval piston motorcycles in the 70's and 80's. They used 4 pistons, each with 2 conrods, 8 valves and 2 spark plugs per cylinder...basically, it was a V8, but fitted within the rules, which stipulated a maximum of 4 cylinders. It wasn't particularly successful, given it was a 4 stroke competing against 2 strokes, but Honda being Honda, they persevered for many years.

The oval piston engine hit its peak in 1992, with the NR750 road bike. Only 300 were built, and they were hugely expensive for the time. They used gear driven cams, and revved to 15,000rpm, huge by 1992 standards!

 

[JHZR2]

Its an interesting concept in a V type engine. In an inline engine, Im not sure I see it.

 

[HTSS_TR]

Originally Posted By: hpb
Honda built and raced V4 oval piston motorcycles in the 70's and 80's. They used 4 pistons, each with 2 conrods, 8 valves and 2 spark plugs per cylinder...basically, it was a V8, but fitted within the rules, which stipulated a maximum of 4 cylinders. It wasn't particularly successful, given it was a 4 stroke competing against 2 strokes, but Honda being Honda, they persevered for many years.

The oval piston engine hit its peak in 1992, with the NR750 road bike. Only 300 were built, and they were hugely expensive for the time. They used gear driven cams, and revved to 15,000rpm, huge by 1992 standards!

I didn't know Honda tried the oval piston/cylinder in the 70's, I thought I hear about it in the 90's.

Honda is usually try new technologies in motorcycle first, if it's a success then they migrate it into car. This is an advantage Honda has over other car manufactures.

 

[hpb]

True. I believe, but could be wrong, that they first used VTEC in a bike engine.

 

[HTSS_TR]

I thought VTEC was first used in a bike engine too, but I was wrong. It was first used in 1989 Integra engine in Japan, first DOHC VTEC engine in USA was in 1991 NSX.

VTEC is almost 30 years old technology but still produce as much power density as newest variable valve timing from any other car company. Not many current normally aspirated engines in the world can make more than 120HP/L as it was in 2000 Honda S2000, a 15 years old car.


Originally Posted By: world.honda.com
This was the so-called "valve stopping + variable valve timing" mechanism employed in the NCE program. As a core technology for Honda's proposed new line of engines, the mechanism then underwent a program of study and refinement under the careful supervision of Honda's research staff. Eventually the mechanism evolved into Honda's VTEC (Variable Valve Timing & Lift Electronic Control System) engine. Launched via the 1989 Integra, this innovative technology surprised the world with a new level of performance from a compact, fuel-efficient engine.


Originally Posted By: world.honda.com
"Find a new technology to lead the next generation of Honda engines." This was the directive issued by the top management at Honda R&D, and in response a project was proposed to expand the variable valve-timing approach. Since it had originally been created to improve fuel economy, the engineering staff's new assignment would be to combine outstanding mileage with impressive output across the entire powerband.

This proposal was approved as a D-development project, and was instituted in November 1986. The objective was to develop a new engine for the 1989 Integra.


Originally Posted By: world.honda.com
Kajitani believed the specification for Honda's new engine - 90 horsepower per liter, or 140 in all from a 1.6-liter unit - was not really reflective of the 1990s approach. After all, the DOHC engine already produced 130 horsepower, but the new engine would only have ten more than that. He knew it just was not enough. Then, as if to read Kajitani's mind, Nobuhiko Kawamoto, then president of Honda R&D made a thoughtful suggestion:

"Why don't you raise your target to 100 horsepower per liter?" he asked.

It had always been thought that a normally aspirated engine could not be made to produce 100 horsepower per liter. But Kajitani could see in Kawamoto the passionate vision of an engineer, and he felt inspired by such a straightforward proposal. Of course, he knew it would mean 160 horsepower from only 1.6 liters, at a maximum of 8,000 rpm.

Kawamoto later became Honda CEO


Originally Posted By: world.honda.com
Honda's new Integra, equipped with the DOHC/VTEC engine, was introduced to the market in April 1989. The VTEC technology drew considerable praise as the world's first valve mechanism capable of simultaneously changing the valve timing and lift on the intake and exhaust sides. In addition to its impressive output and high-revving energy, the VTEC powerplant boasted superior perform-ance at the low end-including a smooth idle and easy starting-along with better fuel economy. It was truly a "dream engine" - a completely new driving experience for motoring enthusiasts around the globe.


Originally Posted By: world.honda.com
"Everyone of us had pledged to do his utmost to create a world-class engine," Kajitani said. "We were confident that variable valve-timing technology would be the next big thing. After all, we had overcome the challenges of development and testing because we knew that only our very best effort would establish this technology.

The DOHC/VTEC engine was subsequently adapted for use in the NSX, Accord and Civic. Following the SOHC/VTEC engine, and then the VTEC-E in 1991, this technology evolved into the three-stage VTEC engine introduced in 1995, which demonstrated an even greater degree of efficiency in output control.



http://world.honda.com/history/challenge/1989vtecengine/index.html

 

[hpb]

VTEC as we know it today began as REV, a system fitted to the 1983 CBR400 - so I think we were both correct in thinking Honda used the technology on bikes first

http://www.autoevolution.com/news/hondas-vtec-system-explained-20338.html

 

[Silk]

They do it in stock (smash up stuff)cars over here, sleeve down 4 cyls in a V8 to make the capacity limit.

 

[hpb]

HTSS_TR, here's another article which better explains the path from REV to VTEC...

http://world.honda.com/motorcycle-technology/vtec/p3.html

 

[HTSS_TR]

Originally Posted By: hpb
HTSS_TR, here's another article which better explains the path from REV to VTEC...

http://world.honda.com/motorcycle-technology/vtec/p3.html

You're correct, the REV (Revolution-modulated valve control) was first used in a motorcycle then it had been enhanced/modified to become VTEC.

That is why I think Honda's advantage over other car companies is they have motorcycle division to try out new technologies.

Yamaha does some works with car companies, they did the SHO engine for Ford Taurus in the 90's, and other engine works for some Japanese companies( I believe Toyota and Nissan).

 

[eddy21]

Originally Posted By: hpb
Originally Posted By: HTSS_TR
Yes, whatever happened to the oval cylinder that Honda talked about some years ago ? Probably didn't do very good in their test(s).


Honda built and raced V4 oval piston motorcycles in the 70's and 80's. They used 4 pistons, each with 2 conrods, 8 valves and 2 spark plugs per cylinder...basically, it was a V8, but fitted within the rules, which stipulated a maximum of 4 cylinders. It wasn't particularly successful, given it was a 4 stroke competing against 2 strokes, but Honda being Honda, they persevered for many years.

The oval piston engine hit its peak in 1992, with the NR750 road bike. Only 300 were built, and they were hugely expensive for the time. They used gear driven cams, and revved to 15,000rpm, huge by 1992 standards!



The oval pistons were to get around a rule loophole no other real benefits.

 

[Trav]

The next VCM fiasco brewing. Honda has a history of building good basic engines then totally ruining those same engines with unproven home brewed whiz bang technology.
IMO it would have been better if they would have just stayed building motorcycles and simple little cars.

 

[A_Harman]

Originally Posted By: AZjeff
Would love to see a computer generated model of the loading/harmonics of the crank.


No you wouldn't!