spurvo

Jee-bloody-sus! Again??? Noooo!!!!!

Um.. I throw in measuring volume of normally induced air moved into and out of the engine (as measured at the throttle plates and single exhaust outlet) per single revolution of the flywheel. Cause.. um.. displacement is volume, and stuff?

Anybody know the numbers for this for a 2.2L four? and for the 13B?

Ooops, flamesuit left off, along with insane list of engineering credentials I don't have. Ouch!

HEns

well, look at it this way, ignore displacement for a second, and look at how much fuel it drinks in comparison, alot more then a 1.3l piston engine.

and apart from the extra hp you get from displacement, its all abt fuel economy.

hahhaha, kinda, my 2 cents

maxcooper

Here are the facts:

A 13B ingests 1.3L of air per revolution of the main shaft. So does a 2.6L 4-stroke piston engine.

A 13B has 2.6L of geometric displacement per rotation of the eccentric shaft. Exactly half of that displacement is not involved in ingesting or exhausting air. This is also precisely identical to a 2.6L 4-stroke piston engine.

The rotary has a 4-phase combustion cycle. Suck, squish, bang, blow. Just like a 4-stroke piston engine.

a 13B has two combustion events (one per rotor) per eccentric shaft rotation. It fires just as often as a 4-stroke 4-cylinder.

It would take 3 full rotations of the eccentric shaft to complete the combustion cycle for all 6 chambers. In that time, it would ingest 3.9L of air.

Feel free to dispute them. I am certain that these are all true statements, so be sure to explain what is wrong with my statement and what the correct answer is. I enjoy the displacement debates. I have learned from them, and I think it is likely that I am not the only one.

-Max

maxcooper

At 100% VE, a 2.2L four takes in 1.1L of air in one crankshaft rotation. A 13B takes in 1.3L of air in one eccentric shaft rotation.

-Max

XSTransAm

Yeah but so does a 2 stroke engine, it sucks the fuel in, squashes it, bang and blows it. (as you put it) however it is efficent enough to fire every two revolutions....

the definition of a 4 stroke engine is that the piston has 4 movements before it can restart its cycle.

down-intake / up-compression / down-power /up-exhaust/

a two stroke just manages to do this all in 2 "strokes"

so does our engine suck, squish, bang, blow more like a 2 stroke or 4 stroke? I dont ******* care

InsaneGideon

... a Jenna Jameson classic!

KevinK2

once you look at the illustrated cycles enough, it's surprising how similar it is to 4-stroke piston engine. may need some brew to free up the mind.

it has tdc and bdc positions where no torque is produced, with max torque at around 1/2 the 'stroke'. intake and exh events start at x degrees bef/aft tdc or bdc.

torque from a piston eng starts with pressure on the piston face creating a force that is always down on the piston. this force is then carried along the rod axis to the crank's offset pin. max instantaneous torque is usually close to the position where the rod is square to the offset crank pin .. around mid stroke.

wankel torque starts with pressure on the rotor face, creating a force. key points:

1) This force direction is always from the face center to the apex seal on the opposite side of the rotor.

2) Force is applied directly to e-shaft offset. You can see in the illustrations that max torque position is when this force vector is square with the e-shaft offset ... near mid stroke.

3) stationary gear is only to control rotor position, and does not produce any engine output torque.

When u think about it, the wankel is a VERY clever way to functionally do exactly what a 4-stroke piston eng does, with fewer parts and less vibration.

spurvo

Nuff said. Thanks Max!

What

*throws in a bag of popcorn in the oven*


I will say that it is pretty disappointing to have a 2.6 liter engine for the rx-anything.

that means that honda has the bragging rights for HP/liter.

Just my thoughts.

jimlab

Naturally aspirated, at 100% VE...

On the other hand, a turbocharged 13B @ 15 psi is ingesting twice the air of a naturally aspirated 13B per revolution, and is therefore equivalent to a naturally aspirated 5.2L piston engine... 2.6L ingested per revolution.

venomrx7

Sorry for catching this so late, but for all the guys saying that the rotary would have to have 3.9 displacemint if anything but 1.3. Your wrong. For it to have 3.9 all 6 chambers would have to be at their maximum capacity, which is impossible.