Does a Nat Asp 6.5 have a higher compression ratio?

[FellowTraveler]

Schiker: No waste gases left in precup, unless you port the precup incorrectly. Yes once compression stroke. gets to point "X" the swirl in the precup is massive and is the key the design. Originally it wasn't called the precup, it was the swirl cup.

Remember Honda cvcc? https://en.m.wikipedia.org/wiki/CVCC
Gee, went from pre combustion chamber to electronic controlled direct injection once the injection tech go good enough, like going to duramax?

FT: exactly! That's why engine designs use the long curved runners as th intakes now. There were some intakes built with mini stationary fan blades factory - vortex increases velocity in a shorter distance than long tunnel, but long tunnel does it better. A Quality head job will do even better, but is way to labor intensive for mass production.

Boost always wins, any plumbing engineers here? There's a formula of pipe size X pressure = volume. In the same area the more pressure you put behind it the faster the medium is going to travel. Just imagine if we could double the rpm of a turbo.

On the air density- oh yeah, way important. Not just the air though. I've spent years on and off working on the end all- be all in my not so humble opinion. People work on 1-10% increases that are awesome and achieve able. My idea is an all or nothing, almost 400% gain in efficiency. No secret swirly ram air action though. I need another 150,000 worth of research to finally prove or disprove it. Been at it as $ permits for about 20 years now. Lots of engines gave their all. So yeah, gonna be a bit yet. Don't worry- if I die my kids will continue the quest. (Insert maniacal laughter here).

I have to say Drago, whenever I here super secret idea, i always get excited. Little ideas of "what if" are how we got most of our cool stuff that didn't exist a couple hundred years ago.

Back to first post, got plans for a project?

Excellent!

 

[schiker]

Yes once compression stroke. gets to point "X" the swirl in the precup is massive and is the key the design.

Did you mean combustion stroke? That's my understanding I thought the precup directs the flame front from the injector spray with a nozzle type affect swirling the air in the cylinder to fully mix and combust all the fuel cleanly.

Referring to our TD 6.5's only here....
To my mind the precup is kind of a dead end street off the cylinder. Once the engine has run one time there is no real start point of cycle. So I say start at end of combustion / power stroke.

The expanded combustion gasses rush out the exhaust valve from heat expansion but the last bit gets pushed out with the exhaust stroke. At the top of the exhaust stroke when the exhaust valve closes there is a volume and mass of air left in the precup and cylinder. How efficient the turbo is and backpressure in exhaust manifold determines the mass of the air (volume is the compression ratio and can't change it). Then air charge comes into the cylinder from boost when intake opens. It will swirl from turbulence but how much flushes the precup is a question for me. I can see some mixing and I think it swirls as the piston travels downward. Then once the intake closes and compression stroke starts its mostly linear compression no flow just compression. The precup gasses get squeezed and might mix some but fully mix I don't know.

Side note another limiter in my mind is piston shape and valve clearance such that valve closing earlier in stroke time than say a DI engine ???? And the different shape of the small volume cylinder size and how to encourage a more momentum scavenging effect of the exhaust stroke.

Imagineering I have pondered almost a tube like air injector built into intake. It would direct a puff or blast of air on initial 1/8 ? of intake stroke to direct and bounce a puff or blast of air to totally flush the precup from a compress air tank. This would be just a quick puff. Boost would still fill cylinder like normal.

Also totally dreaming a ponder to make a changing variable precup volume somehow. And again dreaming a way to build and store a bit of compressed air to help augment boost on initial acceleration until rpm and boost can come up.

 

[Will L.]

Compression stroke-2nd in cycle: intake,compression, power, exhaust.
In what ive seen in the video put out by gm, the momentum of the flame front seemed to clear it. Im sure your right that there is a bit of oxygen free area in the precup that doesnt wash out. But in the compression stroke the oxygen vs nitrogen, i dont think it can add up to enough of to warrant much effort.

Understand 80% of the air in there is nitrogen on its way in and out. How much oxygen needed for the burn is there by volume that your missing out on? Also the more raw fuel that goes unburned going through the precup unburned, is more that can burn on top of the piston. Even if the last sentance is 100% wrong, how much measured oxygen is there in the precup area.

Remember that cvcc honda mimicking the diesel precup was only implimented to get lower emissions, not better power or more mpg. Once the catalatic converter got worked out, gas engines never looked back.

If you have the means to chase it, by all means do. I hate to discourage experimenting- but thats mighty intesive r&d work for what imo would be small to no gain.

 

[Drago]

electronically controlled turbocharger, I use a lot of variable frequency drives for ac motors to control speed at work. why couldn't someone build one that would maintain manifold pressure at zero psi regardless of altitude and engine speed and a boost when you stomp on it.

 

[Will L.]

Build it up! I too wondered why no one has done it yet, but im not a tron guy. I have a run solenoid for a cummins i plan on using as a tm shut off switch to kill boost on flat hiway. Project #482 haha.

 

[schiker]

Yeah, I guess its not really a lack of oxygen otherwise it would smoke more. And I failed to visualize the rapid speed of piston and squeeze into the pre cup. How quickly it compresses the air. It probably does mix all the air up in the pre combustion chamber no real lack of oxygen or pocket of "stale" air.

In my mind a gas engine its more a swirl chamber because it mixing gas and air (they are together before the spark) . In a Diesel to me its more a pre-combustion / separate combustion chamber similar but appreciably different. True its mixing the air on compression stroke inside the pre-cup but its just air. Its a good start but the real mix is the shear through the throat of precup on injection/power stroke.

 

[Husker6.5]

Both Audi and Bentley will be fielding hybrid electric/exhaust turbos for faster low rpm spool up - for emissions not performance reasons, although low end performance will increase due to the increased air charge and hence more complete burn - utilizing in Bentley's case a 48V system for the turbo motor.

 

[FellowTraveler]

Before compound turbocharging became common for diesel road vehicles it was determined to be the best and cheapest way to cleaner emissions and performance.

 

[bobbiemartin]

Hybrid electric turbos have been in Formula 1 for several years. They are extremely complex and the exact details are not shared by the teams, but basically, the turbo can generate electricity for the hybrid battery when not in full use to provide boost or can be electrically spun up to prevent lag. I have read it can also control boost, but they have wastegates as well. The electricity generated goes into a battery. The rear brakes also generate electricity and they have an electric motor to help power the car. It's sort of like a Prius, but far more advanced.

 

[Husker6.5]

When I say hybrid electric turbos, I don't mean using the turbo in a regenerative mode to produce electricity like the brakes on a Prius. I'm talking about a very high speed DC motor coupled to the turbo shaft to keep the compressor spinning and on boost to eliminate turbo lag, such as when down shifting and slowing for a turn then coming back out of it, or coming off of idle at a stop light in stop and go city traffic.

Now, the manufacturers are being as cloak and dagger about their designs as Lockheed's Skunk Works, but the only two ways I can see of doing it is to either make the center section of the turbo into an armature and the center housing a field coil, or to extend the shaft either out the compressor housing or exhaust housing and coupling a motor to either end either directly or by some gear/belt drive.

Either method has its own set of advantages/problems, but that's why the manufacturers spend the Big Bucks on R&D and MIT graduate engineers!

Photos of Lockheed Martin's Skunk Works were taken this winter while on my vacation and passing by on the way to my friend's house in Palmdale from the Sam's Club in Palmdale.

 

[bobbiemartin]

When I say hybrid electric turbos, I don't mean using the turbo in a regenerative mode to produce electricity like the brakes on a Prius. I'm talking about a very high speed DC motor coupled to the turbo shaft to keep the compressor spinning and on boost to eliminate turbo lag, such as when down shifting and slowing for a turn then coming back out of it, or coming off of idle at a stop light in stop and go city traffic.

That is how an F1 turbo works - when it's not generating power. http://oppositelock.kinja.com/f1s-hybrid-turbos-are-awesome-and-you-want-one-in-you-1464497196
Mercedes took in one step further and has the exhaust turbine on the rear of the engine, with the compressor on the front connected by a shaft. BTW, they are 1600cc and are estimated to make 1000 BHP this year - on pump gasoline.

 

[JayTheCPA]

electronically controlled turbocharger, I use a lot of variable frequency drives for ac motors to control speed at work. why couldn't someone build one that would maintain manifold pressure at zero psi regardless of altitude and engine speed and a boost when you stomp on it.

In the aviation community this is known as something like turbo normalization. Common scenario is a piston powered motor with a turbo on it. Except the turbo does not boost more than necessary and keeps the airflow density effectively at ground level despite higher elevations, so actual manifold pressure is close to '0' all the time (from sea level to cruising altitude).

 

[Husker6.5]

That is how an F1 turbo works - when it's not generating power. http://oppositelock.kinja.com/f1s-hybrid-turbos-are-awesome-and-you-want-one-in-you-1464497196
Mercedes took in one step further and has the exhaust turbine on the rear of the engine, with the compressor on the front connected by a shaft. BTW, they are 1600cc and are estimated to make 1000 BHP this year - on pump gasoline.

I'm not talking F1 (I know how those hybrid see ystems work, I also have been following the development of their stored KE system, too ). I'm talking about Bentley and Audi (see my original post) developing hybrid electric/exhaust turbos for use in their street, not racing, vehicles to improve emissions and reduce/eliminate turbo lag in their street diesel engines.

While we're both talking citrus fruit, I'm talking tangelos while you're talking kumquats if you follow my analogy.

 

[Husker6.5]

Systems, not see ystems.

 

[bobbiemartin]

I understand, I was just pointing out the hardware is already in use. From what I understand, VW (Audi, et al) will use two turbos, one conventional and one electric, not a combined unit.

 

[Husker6.5]

I understand, I was just pointing out the hardware is already in use. From what I understand, VW (Audi, et al) will use two turbos, one conventional and one electric, not a combined unit.

Two separate turbos compounded makes sense, but imagine the possibilities of a hybrid electric/exhaust Frankenturbo!

 

[bobbiemartin]

Two separate turbos compounded makes sense, but imagine the possibilities of a hybrid electric/exhaust Frankenturbo!

Which is how they get 10 HP per cubic inch, with fairly limited rules. I'm sure electric hybrid turbos will make their way into road cars before too long. Unfortunately I think VW has other things to worry about with their TDIs right now.

 

[JayTheCPA]

This reminds me of an old co-worker whom grew up in the former Soviet Union. He claims that in the 80's, he took an industrial hand dryer (the high airflow, extremely noisy kind hanging on the wall), retrofitted it to the common box-style 4-banger's intake, and the little car got a huge power boost with the new found airflow. In fairness, he was also known for BS, but it was a good tale.

 

[Husker6.5]

Imagine how long of an extension cord he would have needed!

 

[Drago]

The juice has to be proportional to the boost, doesn't it?