# Thread: Instruction for making a Wankel engine

1. ## Instruction for making a Wankel engine

To design the housing for the Wankel housing you first have to establish the eccentricity.

In this plan we will make the eccentricity one half inch, and the rotor a six inch triangle. Visualize a one inch diameter watch face with 45 successive minute marks starting at the 9 o’clock position and finishing at the six o’clock position.

Each clock minute is exactly six degrees of a 360 degree circle. 9 o’clock is at the 45 minute position. Count from this backwards in a clockwise direction until you have numbered all the minute marks ending with 0 at the six o’clock position.

Draw a horizontal line with a space and a point ending exactly at three inches starting at the 9 o’clock position. The point at the end of the line will be exactly at the minor axis of the housing.

Draw a horizontal line with a space and a point ending exactly at three inches starting at the 44 minute position, then rotate this line two degrees clockwise. Two degrees is one third of the starting point rotation..

Draw a horizontal line with a space and a point ending exactly at three inches starting at the 43 minute position, then rotate this line four degrees clockwise.

Draw a horizontal line with a space and a point ending exactly at three inches starting at the 42 minute position, then rotate this line six degrees clockwise.

Continue this exercise until you have used all the designated minute marks and have a horizontal line with a space and a point ending exactly at three inches starting at the 0 minute position then rotate this line ninety degrees clockwise.

What you will find is a line of dots that make one quarter of a precision Wankel type engine housing.

My experience shows me that Mazda is not aware of this type of precision.

Hope this is of interest.

Ken McKenzie

2. How far apart are the dots and if you draw a line between the dots, does this not leave flats?
This can be done with a mathmatical formula in very very small increments.

3. In the example I used each minute is 6 degrees of a 360 degree circle and each sucessive angle is one third or two degrees.

If you choose to use one degree to progress around the 3/4 circle you would have each progression be a third of a degree.

In the formula when you get to "0" you then continue another 3/4 circle numbering from 1 to 45 this will complete half of the housing and you will show a rotation of one and a half.

do the process again to complete the housing your shown journey will be three revolutions.

Thanks for your interest.

Cheers

Ken

4. Ken,
I can assure you that the response is not indicative of the interest, keep the sharing of your experience going.

I have always found the Wankel engine fascinating and because they were never understood by me , also seemed almost mystical.

Ken

5. Thanks Ken

I have found that the Wankel engine is not understood at all.

Its potential far exceeds our comprehention.

Ken Mckenzie

6. A top priority for maximizing the potential of the Wankel engine requires the utilization of the complete power stroke. The power stroke in a four cycle internal combustion engine consists of the utilization of the combustion pressures that push the piston or rotor from minimum displacement to the maximum displacement.

In the reciprocating piston engine poor energy is created in the 12 o'clock to 1 o'clock and the 5 o'clock to 6 o'clock crankshaft position.

In the Wankel engine poor energy is created at the 12 o'clock to 2 o'clock e-shaft position and maximum energy is produced at the 6 o'clock e-shaft position when the largest third of displacement is about to take place. But unfortunately the exhaust port is opened at this time causing the pressure to go out the exhaust and around the apex seal and into the intake portion of the engine.

This creates serious problems when there are periphery intake ports.

Side ports cause superior separation as the ports are not open until after the exhaust stroke is complete.

Mazda in its new Renesis engine with side intake and side exhaust ports does use a greater portion of the power stroke after the 6 o'clock e-shaft position.

To get maximum torque from a Wankel engine we need periphery intake and exhaust ports as close as possible to the minor axis of the housing and a system that creates perfect separation between the exhaust and intake.

There is a solution, any thoughts?

Ken

7. The previous post regarding instructions for making the Wankel housing, when used will show a line at each minor axis. The design also minimizes apex seal seat wear as there is very small if any in and out movement of the apex seal.

Most think that the e-shaft turns three times for every rotor revolution.

The rotor is compelled to equal rotations with the lobe of the e-shaft.

The Mazda rotor has 51 internal gear teeth of which 34 of them make contact with the stationary gear every e-shaft revolution. Therefore the rotor also makes two thirds of a revolution for each e-shaft revolution.

The two thirds of a revolution cause the rotor to be one surface out of phase every e-shaft revolution.

We watch what appears to be obvious when we claim the rotor turns once for every e-shaft revolution and we are wrong.

If we cut the e-shaft immediately after the lobe (So the rotor would be held in place the same as a rotating foot pad of a bicycle pedal.) and then made a direct drive from the rotor to the drive shaft with a universal joint, or whatever, we would find that the rotor rotates two times for every three e-shaft revolutions.

Gears do the exact same thing every time I am just informing what the gears force the rotor to do.

If you wanted to make a direct gear link from the rotor to the e-shaft lobe the gear ratio would be three to one. But in this instant we are only using the rotating lobe connected by gears to the rotating rotor.

Hope this is of interest

Cheers

Ken McKenzie www.starapex.com

8. Ken,

I am certain there is interest out there, but to help pull others into the discussion it would help if you included geometry figures to follow along with your verbal description.

When I tried to follow the steps to CAD the geometry, I lost track of the terminology used in:

"Draw a horizontal line with a space and a point ending exactly at three inches starting at the 9 o’clock position"

A "from point" is unclear starting at 9 o'clock, as a 3" horizontal line with a space does not tell me where to start or what/where the space should be in that line. Should "space" actually be read as length?

It's mak'n my synapses tired trying to get that much blood in or out of my head to comprehend where it all fits together. On the verge of slpod'n or implod'n, but not quite sure!

DC

9. This program draws the profile. I wrote it for a CAD program but I have put it into Visual Basic to demonstate using a computer to generate the profile.
This drawing has 3600 points.

10. Kiwi

The 3600 points you show results from a generating circle with half the radius of of a base circle rolling around the base circle. A point is positioned at the desired eccentricy and this creates a housing superior to what you depict.

All three points of a triangle will not keep constant contact with it when following it's eccentric path.

The description I provided is for making a precision housing.

Ken McKenzie

11. DC

Sorry for the misunderstanding.

Draw a line starting at the 9 o'clock position from left to right with a space and a dot at the end. The total length including the dot and space is three inches.

Take care
Ken McKenzie

12. Instructions for making a Wankel engine.

If you want an air head understanding of the principles of a Wankel engine look at the many four part drawings that show the intake compression combustion and exhaust strokes.

If you want a true understanding note that for every quarter turn of the e-shaft one third of a stroke takes place on the three surfaces of the rotor.

The beginning of the combustion stroke is the beginning of the second third of the exhaust stroke and also the beginning of the last third of the intake stroke.

Cheers

Ken

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