Flow vs Pressure

[parmas]

Originally Posted by rotrex

He just means 99% purity methanol, but this mixed with distilled water.

Maybe Richard could explain it better?

[Richard L]

I meant 99% pure methanol without traces of hydrocarbon.

[Richard L]

Originally Posted by parmas

1600cc what I calculated, It could be more or less but better be prepared for much than for less.

If you know one big pump ready for methanol able to use 150+psi pressure and flow 6400cc/min please share.

I will not have issues with starting cause I will work with pump fuel for starting/idle/cruising/low boost. At certain boost levels the base fuel will eventually be replaced by methanol injection.

Seems like the best possible setup a street car should actually have although I am ready for critics to say their way.

I have just remembered your set up is based on progressive pump speed (PPS) rather PWM valve. Ignore my PWM valve remarks.

If you are flow this large amount, I am not sure the PPS algorithm will work satisfactorily due to the non-linearity and dynamic range.

[parmas]

Actually I am still determined to find the best setup PPS or PWM . The question is finding the right components that work efficiently without too much complexity and too much expenses

[rotrex]

I personally like the PWM set-up.
Initially it was a Aquamist 2c. Since the race pump dropped in flow rate, I have replaced it with a 160PSI 2.xl/min pump of eBay for €26!. The harness works for the most part except that the pump flow indicator LED is now driven by the 12V line after the pump's micro switch.

The pump has a integrated pressure switch. It stops at about 10bar. Once pressure drops below 8 bar, the pump automatically activates itself. The switch closing fires also the LED. This is my flow indicator. As in the 2c system, I maintained the 30cc accumulator. This dampens the pump switching cycles.
So overall it behalfs like a fuel injection system with pump based pressure control. A bit more crude, but hey.
With this system you end up with a line that is permanently pressurized with your mix.
Next you need to control flow. For this purpose Aquamists sells very suitable valves. I have the older HSV (high speed valve). Now they sell a version called FAV (fast acting valve).
The valve is controlled by my ECU. I use a boost control map with PWM output for this purpose. Most ECUs feature auxiliary PWM maps. The boost control map in open loop mode allows to set a PWM percentage based on throttle position vs. rpm.
This allows me to deterministically set my injection onset and flow rates over the rpm range. The beauty is the proportionality of PWM. If I set it to 70%, I get about 70% of the max. flow rate, if I set it to 30%, I get about 30% flow. It makes the injection a very reproducible and mappable process. I do not need any Hobbs switches to control the system. I still have one to automatically switch to a non WMI map once rail pressure drops below like 5 bar.
Cableing is simple. 12V and ground to the loom, LED and tank level lines to the front., 1 wire from the ECU to control the HSV and 1 line for the map switch as a fail safety.
There is no separate controller and its associated wiring and adjustment knobs. It is all ECU controlled.

Under PWM control, you get spray even at low flow rates as during each opening of the HSV, a full pressure wave passes through the line to the jets.
I can test the pump by pressuring the throttle with the engine stopped.
Over the last 25% of the throttle the valve opens from 0 to 100%.
It works beautifully and you get spray over a big part of the control range.

Pump speed based systems only increase flow by about 40% for a doubling of the pressure.
This is probably why those 250PSI pumps are so popular. You need the dynamic range on the top to get a sufficent controllable flow range as at low pressures, spray is poor.

If you change jet size, all the scaling does not work anymore as pressure vs. flow is now changed. Exception are internal bypass pumps with a constant pressure.

[MaestroB]

Hello!

Sorry for jumping in but actually I'm not replying to this post but as a new comer into the forum, I just want to say hello to you old folks.


Thanks

[parmas]

Originally Posted by rotrex

I personally like the PWM set-up.
Initially it was a Aquamist 2c. Since the race pump dropped in flow rate, I have replaced it with a 160PSI 2.xl/min pump of eBay for €26!. The harness works for the most part except that the pump flow indicator LED is now driven by the 12V line after the pump's micro switch.

The pump has a integrated pressure switch. It stops at about 10bar. Once pressure drops below 8 bar, the pump automatically activates itself. The switch closing fires also the LED. This is my flow indicator. As in the 2c system, I maintained the 30cc accumulator. This dampens the pump switching cycles.
So overall it behalfs like a fuel injection system with pump based pressure control. A bit more crude, but hey.
With this system you end up with a line that is permanently pressurized with your mix.
Next you need to control flow. For this purpose Aquamists sells very suitable valves. I have the older HSV (high speed valve). Now they sell a version called FAV (fast acting valve).
The valve is controlled by my ECU. I use a boost control map with PWM output for this purpose. Most ECUs feature auxiliary PWM maps. The boost control map in open loop mode allows to set a PWM percentage based on throttle position vs. rpm.
This allows me to deterministically set my injection onset and flow rates over the rpm range. The beauty is the proportionality of PWM. If I set it to 70%, I get about 70% of the max. flow rate, if I set it to 30%, I get about 30% flow. It makes the injection a very reproducible and mappable process. I do not need any Hobbs switches to control the system. I still have one to automatically switch to a non WMI map once rail pressure drops below like 5 bar.
Cableing is simple. 12V and ground to the loom, LED and tank level lines to the front., 1 wire from the ECU to control the HSV and 1 line for the map switch as a fail safety.
There is no separate controller and its associated wiring and adjustment knobs. It is all ECU controlled.

Under PWM control, you get spray even at low flow rates as during each opening of the HSV, a full pressure wave passes through the line to the jets.
I can test the pump by pressuring the throttle with the engine stopped.
Over the last 25% of the throttle the valve opens from 0 to 100%.
It works beautifully and you get spray over a big part of the control range.

Pump speed based systems only increase flow by about 40% for a doubling of the pressure.
This is probably why those 250PSI pumps are so popular. You need the dynamic range on the top to get a sufficent controllable flow range as at low pressures, spray is poor.

If you change jet size, all the scaling does not work anymore as pressure vs. flow is now changed. Exception are internal bypass pumps with a constant pressure.

Thank you rotrex for your explaining. I like your system although monitoring flow with an LED seems too simple and I am sure 90% of the time you actually look at the road.

Anyway, just spent some time checking other Aquatec pumps particularly the 550 Series and the 230Volt series. I made a chart for you to review.

Notes :

- The 230Volts consume more power than the 12V series but flow slightly better

- The 550series have double the flow or more the 5800series but they are not capable to withstand pressures for long period of time


Taking into account the rate of evaporation of Methanol vs Gasoline. If gasoline fuel injection systems work with 45psi to 80psi would methanol injection systems need less pressure to vaporize the fuel ?

So why do I need 160psi pressure if I could be good with 80psi @ Pure Meth?

What about Water/Meth mixtures would I still have good evaporation @ 80psi and W25/M75 ?

[rotrex]

If you just want to get the methanol to burn in the cylinder as a fuel, the spray quality (small droplet size and narrow distribution) is not as important as if you like to preferentially cool the air. For water this is even more important as its evaporation speed is so low.
For methanol as a fuel and power as the main objective with emissions lower on the list, you get away with a crude spray. Most of the fuel, being petrol or methanol or ethanol evaporates hitting the hot valves and combustion chamber walls.

Hydraulic nozzles produce finer mist at higher pressures. This is where the need for high pressures come from. Making fine mist of water or water / meth mix.
Air assitted nozzles work with much lower fluid pressures, but for very high flow rates, need high air pressures.

Fuel injectors have overcome this droplet size to a degree by adding holes to the injectors with some having as much as 12 holes, e.g. The Denso injectors for the 2003-2009 Toyota Prius. For this car this was done to achieve a very fast fuel evaporation and homogenous distribution lowering emissions. Lean pockets increase Nox emissions, rich pockets CO and HC.

so yes, for pure methanol or mixes high in methanol content, you get away with bigger droplets. This is why I proposed a methanol or ethanol compatible secondary fuel injector system. But unfortunatly your ECU does not support it.

the LED is crude, but all I need. Closed loop fueling, a very fast knock controller and pressure based fail safety take care of the rest. If it fails, I get misfires and knock. Nothing brakes. I have tried it when the race pump dropped in flow and for a strange reason the priming pump controller was also not activated anymore by the pressure switch of the race pump.
fitting a membrane pump solved this. I have a spare on in the shelf shall I got problems again.

This is new pump I got on eBay, except it says 1.1 Mpa on the label instead of 1 Mpa as on the picture.
I cut the barbs off and cut 1/8" threats into the plastic to fit pushy on connectors.

[parmas]

ANSWER IN CAPS

Originally Posted by rotrex

If you just want to get the methanol to burn in the cylinder as a fuel, the spray quality (small droplet size and narrow distribution) is not as important as if you like to preferentially cool the air. For water this is even more important as its evaporation speed is so low.
For methanol as a fuel and power as the main objective with emissions lower on the list, you get away with a crude spray. Most of the fuel, being petrol or methanol or ethanol evaporates hitting the hot valves and combustion chamber walls.

AGREED


Hydraulic nozzles produce finer mist at higher pressures. This is where the need for high pressures come from. Making fine mist of water or water / meth mix.
Air assitted nozzles work with much lower fluid pressures, but for very high flow rates, need high air pressures.

AGREED


Fuel injectors have overcome this droplet size to a degree by adding holes to the injectors with some having as much as 12 holes, e.g. The Denso injectors for the 2003-2009 Toyota Prius. For this car this was done to achieve a very fast fuel evaporation and homogenous distribution lowering emissions. Lean pockets increase Nox emissions, rich pockets CO and HC.

THESE INJECTORS ARE STOCK USED FOR MY ENGINE. TRIED TO USE THEIR ORIFICE MATED WITH A BILLET NOZZLE. SPRAY WAS ALMOST LIQUID MAYBE DUE TO PRESSURE DISTRIBUTION ON 12HOLES. ALSO THE ORIFICE CORRODED AND BLOCKED HOLES WERE AN ISSUE.


so yes, for pure methanol or mixes high in methanol content, you get away with bigger droplets. This is why I proposed a methanol or ethanol compatible secondary fuel injector system. But unfortunatly your ECU does not support it.

NEED TO TRY A W25/M75 @ 80PSI PRESSURE L

the LED is crude, but all I need. Closed loop fueling, a very fast knock controller and pressure based fail safety take care of the rest. If it fails, I get misfires and knock. Nothing brakes. I have tried it when the race pump dropped in flow and for a strange reason the priming pump controller was also not activated anymore by the pressure switch of the race pump.
fitting a membrane pump solved this. I have a spare on in the shelf shall I got problems again.

This is new pump I got on eBay, except it says 1.1 Mpa on the label instead of 1 Mpa as on the picture.
I cut the barbs off and cut 1/8" threats into the plastic to fit pushy on connectors.

[parmas]

Originally Posted by rotrex

the LED is crude, but all I need. Closed loop fueling, a very fast knock controller and pressure based fail safety take care of the rest.

Thinking ahead.... could you give more details on the above ?