Megasquirt Rotary Specific Feature Requests
09-20-10, 08:35 AM
#1
Rotary Specific Feature Requests
Hi Ken,
Are these following options possible.
Returning from fuel cut enrichment, first cycle, decay, rate, number of cycles...
Rear rotor only fuel cut and associated return from rear rotor fuel cut
Distance from port inputs for injection timing. To me it would make sense to model the speed in the manifold based on manifold pressure and tell the ECU the engines port timing and injector distance from valve/port and have the ECU work out ideal injection time, and then with that on you tune the deviation from ideal. And with it off you have 100% control over injection time.
I would like to be able to deliver the petrol as early as possible in each cycle to reduce the effects of the rotaries intake ports closing after bottom dead centre.
Is it possible for you to modify the throttle wizard to have a count on number of cycles rather than injection time. I've got Mazda SAE **** that says you want only a single enriched shot. However I've noticed when cold maybe an extra shot or to helps throttle response.
Also I will require modified primary to secondary injection angles, as the injector distance from port varies primary and secondary, as does the port timing. Is proper staging possible where the injection pattern remains sequential once the secondaries are on. I realise all this is a nightmare when it comes to MCU timers etc but I feel if the ECU is sequential all that is required.
Are these following options possible.
Returning from fuel cut enrichment, first cycle, decay, rate, number of cycles...
Rear rotor only fuel cut and associated return from rear rotor fuel cut
Distance from port inputs for injection timing. To me it would make sense to model the speed in the manifold based on manifold pressure and tell the ECU the engines port timing and injector distance from valve/port and have the ECU work out ideal injection time, and then with that on you tune the deviation from ideal. And with it off you have 100% control over injection time.
I would like to be able to deliver the petrol as early as possible in each cycle to reduce the effects of the rotaries intake ports closing after bottom dead centre.
Is it possible for you to modify the throttle wizard to have a count on number of cycles rather than injection time. I've got Mazda SAE **** that says you want only a single enriched shot. However I've noticed when cold maybe an extra shot or to helps throttle response.
Also I will require modified primary to secondary injection angles, as the injector distance from port varies primary and secondary, as does the port timing. Is proper staging possible where the injection pattern remains sequential once the secondaries are on. I realise all this is a nightmare when it comes to MCU timers etc but I feel if the ECU is sequential all that is required.
09-21-10, 03:17 PM
#2
MegaSquirt Mod
Rear rotor only fuel cut and associated return from rear rotor fuel cut
Distance from port inputs for injection timing. To me it would make sense to model the speed in the manifold based on manifold pressure and tell the ECU the engines port timing and injector distance from valve/port and have the ECU work out ideal injection time, and then with that on you tune the deviation from ideal. And with it off you have 100% control over injection time.
I do plan on adding a second timing table for injection for the secondaries though for 1.0/1.1.
Is it possible for you to modify the throttle wizard to have a count on number of cycles rather than injection time. I've got Mazda SAE **** that says you want only a single enriched shot. However I've noticed when cold maybe an extra shot or to helps throttle response.
I could definitely make standard accel cycle based pretty easily though... EAE already is.
Also I will require modified primary to secondary injection angles, as the injector distance from port varies primary and secondary, as does the port timing. Is proper staging possible where the injection pattern remains sequential once the secondaries are on. I realise all this is a nightmare when it comes to MCU timers etc but I feel if the ECU is sequential all that is required.
I could probably add a mappable transport delay too, but I figured why do that when you can just fold that into the timing and have fewer tables to tune.
Ken
09-21-10, 11:47 PM
#3
Hey Ken,
Cheers for your comments. I'm throttle body injected at the moment so EAE is 100% no help there. There is way too much wall to wet for me to get that tuned. When I have injectors in primary ports 4cm from chamber I will certainly give EAE another go.
So at this stage cycle based throttle wizard would certainly help.
Nevermind about injection modelling. I would really appreciate secondary injector timing control independent of primaries.
Regarding rear rotor only fuel cut. If you take a squize through Mazda SAE's on the FC3S there are load points where there is 100% fuel cut, and during more modest decell there are load points where the ECM will cut rear rotor fuel, and inject more heavily into the chamber not being cut to get economy and smooth running, and not burn out the cat from lean excessive high EGT's whilst cruising on the highway for hours on end. In my mind you would want options to enable rear rotor only, and make them more modest then full fuel cut, and then have it kick back to 2 rotor fueling with a certain throttle position.
Can you tell me about the actual nature of throttle pump, like is it possible for the enrichment through the wizzard to come out through the secondary injectors? What about when EAE is in use?
Cheers for your comments. I'm throttle body injected at the moment so EAE is 100% no help there. There is way too much wall to wet for me to get that tuned. When I have injectors in primary ports 4cm from chamber I will certainly give EAE another go.
So at this stage cycle based throttle wizard would certainly help.
Nevermind about injection modelling. I would really appreciate secondary injector timing control independent of primaries.
Regarding rear rotor only fuel cut. If you take a squize through Mazda SAE's on the FC3S there are load points where there is 100% fuel cut, and during more modest decell there are load points where the ECM will cut rear rotor fuel, and inject more heavily into the chamber not being cut to get economy and smooth running, and not burn out the cat from lean excessive high EGT's whilst cruising on the highway for hours on end. In my mind you would want options to enable rear rotor only, and make them more modest then full fuel cut, and then have it kick back to 2 rotor fueling with a certain throttle position.
Can you tell me about the actual nature of throttle pump, like is it possible for the enrichment through the wizzard to come out through the secondary injectors? What about when EAE is in use?
09-22-10, 10:18 AM
#4
MegaSquirt Mod
Regarding rear rotor only fuel cut. If you take a squize through Mazda SAE's on the FC3S there are load points where there is 100% fuel cut, and during more modest decell there are load points where the ECM will cut rear rotor fuel, and inject more heavily into the chamber not being cut to get economy and smooth running, and not burn out the cat from lean excessive high EGT's whilst cruising on the highway for hours on end. In my mind you would want options to enable rear rotor only, and make them more modest then full fuel cut, and then have it kick back to 2 rotor fueling with a certain throttle position.
That said, I would think that you wouldn't want to favor one rotor or the other since that would potentially make them wear differently.
I can think about doing a fuel cut on one rotor only, but the current code does not make that easy.
Can you tell me about the actual nature of throttle pump, like is it possible for the enrichment through the wizzard to come out through the secondary injectors? What about when EAE is in use?
EAE actually has its own set of curves for secondaries on ms3, so you can tune the curves independently.
Ken
09-23-10, 03:12 AM
#5
Actually, this is where it helps the most. It is a lot different to tune this way, but I've seen it successfully tuned on TBI.
I'll have to think about that. Just going lean won't burn out a cat though. Highest EGT is at 14.7, going leaner than that drops the EGT.
That said, I would think that you wouldn't want to favor one rotor or the other since that would potentially make them wear differently.
I can think about doing a fuel cut on one rotor only, but the current code does not make that easy.
It actually does come out through the secondaries. IT is applied to the PW BEFORE doing the calcs to split between primaries and secondaries. So part of it comes through the primaries and part through the secondaries.
EAE actually has its own set of curves for secondaries on ms3, so you can tune the curves independently.
Ken
I'll have to think about that. Just going lean won't burn out a cat though. Highest EGT is at 14.7, going leaner than that drops the EGT.
That said, I would think that you wouldn't want to favor one rotor or the other since that would potentially make them wear differently.
I can think about doing a fuel cut on one rotor only, but the current code does not make that easy.
It actually does come out through the secondaries. IT is applied to the PW BEFORE doing the calcs to split between primaries and secondaries. So part of it comes through the primaries and part through the secondaries.
EAE actually has its own set of curves for secondaries on ms3, so you can tune the curves independently.
Ken
Well you could alternate fuel cuts 100 cycles per rotor or something, we are talking about basically zero load points btw like just off fuel cut. Also remember pumping losses go down as the throttle gets opened more.
10-07-10, 10:48 PM
#7
My car is running pretty mint atm. I'm using 195500-2020 High-Z 550cc Purple top primaries, with Bosch Indy White 1600cc secondaries (4.6Ohms) with current limiting disabled. Its running pretty bloody well.
All the problems I was having at low loads were small setup issues.
I'm still daily driving on the 2.10d which you emailed me around september 2008
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10-28-10, 09:49 PM
#8
Just a note on the rotor fuel cut... if you aren't burning at all in one rotor & still pumping air through, then that extra airflow is going to really cool off the exhaust since roughly half the flow is ambient, outside temperature. If anything, this will cool the cat off to the point that it basically just stops working b/c of short gas residence times in the cat & cool temps.
Cutting one rotor would be interesting from a fuel economy standpoint, but without drive-by-wire control & some spark timing controls for torque management, it'll never be smooth going into & coming out of it. I did something like this, but just with switches to the 12V supply for injectors, on each bank of the PRV V6 in my brother's old volvo. Unfortunately, this doesn't keep you from incurring the friction loss that goes along with these cyls, or the pumping, and if you only have a single O2 sensor it will read really lean because of all the fresh air thats mixing with the burned exhausts, causing any sort of closed loop control to dump in more fuel making the firing cyls rich. Basically, I got the same MPGs over an identical route using all 6 cyls as I did when trying to use 3 cyls as much as possible (although it was slow as all hell that way, so all 6 came on for most acceleration). Also, if you're still using any of the hardware boards prior to the dedicated MS3x board, you can't cut fuel to just one rotor since there are only two fuel channels, one for primaries on each rotor and one for secondaries.
Cutting one rotor would be interesting from a fuel economy standpoint, but without drive-by-wire control & some spark timing controls for torque management, it'll never be smooth going into & coming out of it. I did something like this, but just with switches to the 12V supply for injectors, on each bank of the PRV V6 in my brother's old volvo. Unfortunately, this doesn't keep you from incurring the friction loss that goes along with these cyls, or the pumping, and if you only have a single O2 sensor it will read really lean because of all the fresh air thats mixing with the burned exhausts, causing any sort of closed loop control to dump in more fuel making the firing cyls rich. Basically, I got the same MPGs over an identical route using all 6 cyls as I did when trying to use 3 cyls as much as possible (although it was slow as all hell that way, so all 6 came on for most acceleration). Also, if you're still using any of the hardware boards prior to the dedicated MS3x board, you can't cut fuel to just one rotor since there are only two fuel channels, one for primaries on each rotor and one for secondaries.
10-29-10, 11:22 AM
#9
MegaSquirt Mod
Most piston engines that come with "displacement on demand" can also stop the valves from opening on the cylinders that aren't going to fire to get rid of pumping losses and to retain the ability to run closed loop.
Ken
Ken
10-29-10, 03:09 PM
#10
Yea, but on a rotary if you did the equivalent (closing valves to the rotor's intake tracts), you'd have no way of getting the oil from the oil injectors into the rotor besides as a trickle down the wall (not dispersed in the airflow). That trickle would be much larger than normal due to the larger throttle opening required, but it may not get to the whole apex seal. If you run premix, then the opposite would happen; no fuel to a rotor = no oil. Rotaries don't really lend themselves to displacement-on-demand type operation
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