If you firing a rotary engine six times every 10 degrees at 10,000 RPM you
need a fast crank angle sensor.
This has a rise and fall times of about 20 nano seconds. A nanosec
is one one thousandth of a micro second. Of course everybody knows
a micro second is one one millionth of a second.
Consequently a nano second is a short period of time to say the least.
Naturally I am very pleased with this device. It is molded plastic
and strong as brick. I'll be sending it off on Monday to Poul
Woelflein Germany so he can mount it on the e-shaft of an AIXRO kart
rotary for testing our new patent pending high speed CD ignition
in a week or two.
It has the promise of reducing the fuel consumption, increasing
the power, reducing hydro carbon emissions and curing an occasional
mis-fire at idle due to port overlap. It is six times more likely
to fire a bad mixture.
The pulse width shown is about one millisecond and the pulse
amplitude is zero to 12 volts. A very solid and unambiguous signal.
Paul Lamar
Paul, First the crank angle sensor. Will this sensor match up with ECU,s
currently on the market or will they have to be adapted to read the signal?
What price for your sensor?
Second, while talking to Motech they keep quoting the AEM CDI inductive
coils. There are the Smart and dumb coils. So that I can do the
impossible
and sound intelligent, What is the difference and which suits the rotary
best?
Thirdly, what are the advantages of your coil to the AEM coils
Neil.
ECU's on the market wont' spark more than once. They must be reprogrammed
to spark multiple times.
The trick is use my trigger mech and disconnect the ECU from the
ignition system.
My system has the coil built in. No other coils needed. The spark comes
out of the brass
post and is connected to the spark plug with off the shelf spark plug
wire and spark
plug connectors.
Smart coils are old fashion Kettering coils with a transistor built in.
No more points.
However they work the same way
and they must be turned on well before the spark is required. It is called
dwell time and the old distributors did that automatically. Dwell is usually
about 2 ms on the RX8 smart coils so it only takes 8 ms to rotate 360
degrees at
7500 RPM. So you can see the limitations. 2 ms and you are 90 degrees
after firing time at 7500 RPM.
CD systems do not require dwell time, mine included. They fire the plug when
told to fire the plug with no delay. However CD systems on the market
use external coils and they have trouble firing more than once above
4500 RPM.
Mine can fire alot at any RPM :)
The cost of the trigger mech rough guess is about $200. Much cheaper
if you can talk the ECU guys into reprogramming as all you need then
is a traditional CAS.
Paul Lamar
Neal, One thing I forgot to mention about smart coils( AKA coil on plug).
Tracy adopted the LS1 coil on plugs from the Chev V8. The probelms
with that is a 4 cycle engine fires half as often as a rotary and the
LS1 coils
were not up to it. Tracy went trough a bunch of troubles until he put them
into a box and installed a cooling blast tube. At a given RPM twice as much
current flows through the LS1 coil when it is used on a rotary.
Also GM came out with the LS2 version that had a heat sink.
I had several discussions with Tracy on this subject but he ignored me :)
Then the RX8 showed up with coil on plugs in 2004. Early RX8 coils were
overheating and failing so Mazda came out with an improved version around
2006. The trouble is; nobody drives an RX8 at 6000 RPM let alone 7500 RPM
continuously. At 7500 RPM and with a 2 ms dwell time the coil is conducting
several amps for 25% of the time and gets very warm to say the least.
Needless
to say I installed a heat sink on Milo's engine for the RX8 coils.
One of the revolutionary features of my coil on plug ignition is it's
extreme efficiency.
It draws less than .1 amp (one tenth of an amp) at 10,000 RPM firing
six times. It runs
cool to the touch. That feature alone means it has a bright future.
Paul Lamar
Paul,
All makes sense. My current problem is that once I get over 6100
RPM I get a bad miss. Have checked everything possible wiring wise, changed
plugs to many and varied varieties to no avail. Now getting to the "spit
the dummy" stage. I have Bosch coils with a trigger box so they are "dumb"
coils. At 6100 rpm the engine is working very hard, near max. so the
slightest thing will cause a miss. Now looking at replacing the coils with
AEM to see if I can get some joy. Already tried changing the Bosch coils
around to again no effect. I have nothing else to try. Any suggestions?
Under 6100 everything is perfect.
Neil.
Could be a software problem.
The computer must work fast to calculate the dwell time at
high RPM.
Send me the Microtech list of parts you have.
Do you have an old fashion timing light?
Mark your e-shaft pulley at 20 degrees BTDC with a bit of
white paint.
Shine the timing light on the mark with the engine running.
Rig something to hold the light with duct tape.
A small digital camera looking at the mark will record what
is happening at 20 to 30 frames per second. You can email
me the movie. At 6000 RPM the engine is turning 100 revs
per second so we should see something every now and
and then. This is a poor man's data acquisition system :)
You will not have to stand next to the engine while it is turning
up at 6100 RPM inches away from the prop to do this.
I am not that brave :)
Especially if you can rig a way to turn the camera on and
off. I can dissect the movie frame by frame.
If you record for more than 30 seconds or a minute the video
file gets too large to email so do it it short "takes" if possible to use
a term from the movie industry.
The other thing you will need if the movie is too long to email
is movie editing software. Pinnacle works for me.
http://www.pinnaclesys.com/publicsite/us/home/
One second thought a higher speed DA system would be better.
You connect it to all four wires going to the coil primaries.
This is a reputable company and I can buy one for you and
ship it parcel post.
http://www.dataq.com/products/startkit/di145.html?source=googleda&gclid=CNasr8ro7L4CFRRsfgodXDUAHA
It sends the data to software in the PC through a USB port..
Paul Lamar
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