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rv6ejguy

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It is standard practice on the Pratts to enrichen and re-lean every hour or 1,000 foot of altitude change. It is good to start at a baseline periodically with them.
I've flown Pratt DC-3s a bit, right seat, eons ago. Never did this. Select auto-rich or auto-lean as the case may be.

In any case, we don't do this on modern EFI equipped engines either. Once cruise power is set, we select LOP mode usually via the switch or keypad. This leans the programmed amount (usually 20-25%) and simultaneously advances timing 3-5 degrees to help restore some of the lost power due to the slower burning lean mixture. Climb mixture is automatically controlled by MAP and baro.

I thought this thread was about simple EFI to replace carbs on small 2 and 4 stroke engines. What will be gained with more layers of complexity on these small engines which don't burn much fuel to begin with? 2 strokes certainly don't take kindly to be running lean at all.

We are currently working with a company in the US to develop an SDS kit for the Honda 650 single cylinder engine for aviation.
 
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Hot Wings

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<< >> but activation is still using the biological ECU (pilot) as the logic signal.
Thanks! So it turns out that we ARE in agreement.

It matters not if we are interacting with a machine or a human. If we don't tell them what outcome we want the other party is left to guess our intent. Once the goal is established we can then let our CPUs and political representatives take care of the details.
The CPUs probably do a better job. ;)
 

jbiplane

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Exept for ECU other components of kit very important
1. Tested GY6 generators stock. Got only 24W at 5000rpm with stock rectifier. Make our in-house. Result on graph.
test.jpgPower Gy6.jpg
Second - using different third part components we made in tank brushless pump with pressure regulator which weight 212grams and consume just 12W.
 

Vigilant1

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Custom fuel pumps and alternators, this could get expensive.
 

jbiplane

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Care to share which engine this this is for
This time EFI installed on chinese DLE60 boxer to increase range of cheap survelance UAV.
Me produced only 90,120,183,236,250,294,344,350 boxers and 141cc inline.
Now trying make 207 and 1300cc wankels and big V90 2-stroke.
 

Vigilant1

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Work in progress
View attachment 108371
1 - Brushless intank fuel pump assembly with pressure regulator
2 - Denso smart coil
3 - ECU mounted on throttle body
4 - throttle body 22, 24, 26, 28, 30mm
5 - Brushless generator (if stock motor does not have)
6 - fuel nozzle
7 - voltage stabilisator
View attachment 108372
All stuff together weight below 1kg
View attachment 108373View attachment 108374
Thinking about existing V-twin 4 strokes or more:
What's the max flow of the fuel pump? Can it supply 2gph (125 ml/min)? And, depending on requirements, you are planning for the ability to feed 2 nozzles/injectors/throttle bodies, right?
If each throttle body is entirely independent (own controller, sensors, etc) and inexpensive, then inflight reliability becomes easy to achieve through redundancy (assuming there are not other single-point-failure modes: electrical, fuel filter, etc).
Two parallel, independent "consumer quality" pieces each with a 1 per 500 flight hour failure probability would have a combined 1 per 250,000 flight hour failure probability. I'd guess most E-AB builders would probably be okay with that.
The "independent" aspect deserves careful thought If a single overvoltage spike kills all EMUs, then, well they weren't really independent.
Thanks.
 
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rv7charlie

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Translating that into units we barbarians can understand, that's 5.2 gallons per hour. We must be talking about a *really* small engine, if it's for an a/c installation. Isn't the FAA-standard flow supposed to be something like 1.2 times the max fuel consumption of the engine, if it's pumped, and 1.5 times, if gravity fed?

Earlier, you mentioned designing something for '1300cc Wankels'. Are you considering a fuel/ignition controller for the Mazda 13B & Renesis engines? Software configured for the Mazda trigger wheels, etc? Arduino, or a 'real' engine control chip as the processor?

Thanks,

Charlie
 

Vigilant1

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This pump have max flow 20liters per hour or 330ml per minute at low pressure 125 for 3bars looke achievable. Possible instal few for redundancy.
A 30 HP 4 stroke would need about 2.25 GPH (142 ml/min) at full power, no cushion for the FAA, etc. So, if we could get by with less than 3 bar (44 psi, which is a typical FI rail pressure) then one pump might do. For this case, probably better to have two such pumps in parallel with appropriate check valves to give plenty of flow and also allow nearly max power if one failed.
 

rv7charlie

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Might sound trivial to quibble over .5 gph, but at these levels, it's a lot. (Parse that sentence...)

Full power operation typically requires a richer mixture; if the engine is air cooled, it's essential that it be quite rich. .55 lbs/hr is a borderline number for air cooled engines; that works out to .55*30=16.5lbs/6=2.75 gph.

For perspective on the electric fuel pump issue, typical automotive fuel injection pumps are capable of 2-3 times the max flow of the engine.
 

Vigilant1

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Well, if 30 hp is the rqmt, maybe a different OTS pump would be better. Also, I'm not sure how critical the fuel rail pressure is. I know some backyard Arduino systems have gotten results their builders felt were acceptable using inexpensive high flow, low pressure (5 psi) pumps designed for use with carburetors. I'm sure the injector spray pattern suffers, but I don't know the hit that BSFC takes due to that. It might be highly dependent on the particular induction system setup. Some engines do well with nothing more sophisticated than a fuel dribble into the airflow. If jbiplane's pump flows 330 ml/min (5.2 GPH) at a fuel pressure that produces acceptable results, that gets us well into the hopped up 1000 cc V-twin range.
If the EFI won't be using closed-loop mixture control or a fuel pressure sensor, then consistent fuel rail pressure would be important. That argues for a pump/system that meets max flow without a significant pressure drop.
The "lumpy" induction flow of the V-twins really benefits from a separate injector for each cylinder. If each injector gets its own pump, and if 45 psi fuel is needed, this existing pump might work fine for one side. But, unless the engine keeps running on one jug and you can fly on significantly reduced power, then failure of either pump results in a forced landing.
 
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jbiplane

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designing something for '1300cc Wankels'
At moment making only 3d modelling part of this project. Had an experience install EFI on 294cc wankel.
pump flows 330 ml/min
I use it on overboard Yamaha 9.9...40hp and paramotor engines. For bigger engines easy find bigger pumps.
The challenge was fit injection + ignition to 35w
 

Armilite

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A 30 HP 4 stroke would need about 2.25 GPH (142 ml/min) at full power, no cushion for the FAA, etc. So, if we could get by with less than 3 bar (44 psi, which is a typical FI rail pressure) then one pump might do. For this case, probably better to have two such pumps in parallel with appropriate check valves to give plenty of flow and also allow nearly max power if one failed.
=========================

Are you comparing Certified Engines vs Exspermental/Part 103 Engines?

If a Water-Cooled Engine is making 30hp at .5 = 2.50 gph!

If an Air-Cooled Engine is making 30hp at .55 = 2.75 gph!

While the difference for USA Part 103 isn't really affected much, not everyone in the World faces the same limitations of only carrying 5 Gallons as we do.

At Full 30hp Power:
5.0/2.5 = 2.0hrs
5.0/2.75 = 1.81 hrs

30hp at 75% Power is 22.5hp
22.5hp at .5 = 1.88 gph. 5.0/1.88 = 2.65hrs!
22.5hp at .55 = 2.06 gph. 5.0/2.06 = 2.42hrs!

30hp Engine! Sizing Injectors for EFI needed. While I have seen (2) Injectors used per Cylinder, most Engines only use (1) per Cylinder.
(1) Injector
Naturally Aspirated
80% Duty Cycle
19 LB/HR
197 CC/MIN
=====================
30hp
(2)
Injectors
Naturally Aspirated
80% Duty Cycle
9 LB/HR
98 CC/MIN
====================
30hp
(3)
Injectors
Naturally Aspirated
80% Duty Cycle
6 LB/HR
66 CC/MIN
===================
30hp
(4)
Injectors
Naturally Aspirated
80% Duty Cycle
5 LB/HR
49 CC/MIN

GPH USE.jpg
 

jbiplane

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Lets compare proposed injection kit with the simplest carburetor + magneto. What we lose by weight

Paramotor case
The lightest possible set typical for 180cc motor (some like Simonini have generatao and all together weighs 2000+ grammes)
magneto + carburetor per paramotor (exist rotors and coils heavier, dont care weight of adapters bolts, wires, caps...)
Rotor 350 + Coil 252 + carburettor 206 = 808 grams

Injection kit for 150... 350 cm

Body with electronics and wires 282
Fiducial disk (optional) 64
Our nozzle with connectors and adapters 42 (Vazovskaya slightly heavier)
Car DPKV with attachment 54 (we have Panasonic with attachment 16 grams)
Assembly of fuel pump with pressure regulator and fuel level indicator 216
Ignition coil 154
Nozzle housing adapter (optional) 97 can be made of plastic
The total weight of the experimental set is 909 grams - 101 grams heavier than the
lightest version of magneto with carburetor. This weight can be optimized but it will increase cost.

If there is no generator on the engine, then our complete set with a rectifier and a mount = 614 grams
(you can make it easier, we used 5050 brushless motor, Vitorazzi puts 3650)
Battery 160 grams (if it was not originally), it is enough for 2 hours (if the generator fails)
Total, in a pessimistic arrangement, we increase the weight by 875 grams

In our opinion, the pros worth it
spark energy 6... 10 times higher
engine started from the first turn at heat, cold, highlands
fuel consumption become less at least 25%,
the engine becomes slightly more powerful 3... 7%
piston blowing is excluded
fuel reserve in the tank can be viewed in real time
all engine information can be viewed in real-time on the phone or tablet
(you can compose the dashboard yourself or use the ready-made ones)
 
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