Timed Duty : Direct Port Injection

[parmas]

I am considering the Direct Port injection on the next setup build although during some research this came to my mind and I just could not stop thinking......

Pre-throttle body Injection :

As soon as target boost value is achieved the pump progressively switches on and pressurize the check valves. Above the check valve pressure value the nozzles begin to mist the mixture progressively.

The plenum delivers the mixture to the cylinders accordingly until throttle is closed

Direct-Port Injection :

Repeat : As soon as target boost value is achieved the pump progressively switches on and pressurize the check valves. Above the check valve pressure value the nozzles begin to mist the mixture progressively.

All Four nozzles (in case 4cyl) begin misting the mixture into the port simultaneously until I say --- WHAT! the hell am I doing????

We all know that fuel injection happens in TIME and DUTY. Injecting all injectors at once will actually inject ALL THE TIME at different duty at a closed valve while the cylinders could be doing three different stokes rather than the intake cycle!

The only way to properly design direct port injection is to have a timed-duty setup that injects the mixture in time of that intake event on that particular cylinder at different duty cycles. This could be done by the use of fast acting relays and line pressure always ready to inject.

Would be more worth using a pump and injectors rated safe for methanol and connect them directly to ecu ?

[rotrex]

Parmas, at at higher injector duty cyles at WOT, e.g. 70%, The Fuel injectors Are open most of the time. In a port injector set-sequential injection is mainly for low load and low to mid rev emissions. if your duty cycle hits 90% they are open 90% of the time, this means also open when the intake valve is closed . It is no big deal

[parmas]

Parmas, at at higher injector duty cyles at WOT, e.g. 70%, The Fuel injectors Are open most of the time. In a port injector set-sequential injection is mainly for low load and low to mid rev emissions. if your duty cycle hits 90% they are open 90% of the time, this means also open when the intake valve is closed . It is no big deal

Rotrex, as you said above 70% injectors are open MOST of the time and not ALL the time.

The 30% difference of a direct port injection system will result mainly in :

- Wetting valves/walls with methanol
- Valve Guide lubricity issues
- Extra Fuel consumption
- Enhance Corrosion of metals
- Resulting in 100% Relative Humidty (Hurts Evaporation)

Considering the next methanol build, I am planning to run and depend particularly on the direct port methanol setup while on boost. According previous datalogging injector duty cycles vary from low boost 30% to high boost 60%.

What would happen if I begin direct port injection at low boost ?

[rotrex]

If you go for a secondary methanol injection, you might consider fuel injectors. This allows for full sequential injection . Do you have a cam sensor to run sequential? Does you ECU support a second injector bank incl. transition management?
Power wise sequencial makes no difference. It is purely done for emissions reasons.
If you need additional water, just use you WI system.

If you want to avoid valve wetting, you need direct injection.

[rotrex]

You can inject as early as you cannot reach MBT anymore. I start at about 0.3 bar.

[parmas]

If you go for a secondary methanol injection, you might consider fuel injectors.

FUEL INJECTORS COULD NEED TO BE FLUSHED AND METHANOL INJECTORS ARE EXPENSIVE AND NORMALLY FLOW MUCH.

This allows for full sequential injection . Do you have a cam sensor to run sequential?

YES. RUNNING FULL SEQUENTIAL

Does you ECU support a second injector bank incl. transition management?

PROBABLY YES BUT I HAVE TO CONFIRM WITH HALTECH

Power wise sequencial makes no difference. It is purely done for emissions reasons.

I DON'T AGREE. EFFICIENCY MAKES POWER EVENTUALLY

If you need additional water, just use you WI system.

A HIGH PERCENTAGE OF METHANOL IS BEING CONSIDERED

If you want to avoid valve wetting, you need direct injection.

AGREED BUT NOT WITHOUT MATCHING INTAKE TIMING


...........

[rotrex]

According to Dave Walker, owner of Emerald ECU and very exerpeicned dyno operator says no. It makes little to no difference in power. He tried it. It is mainly done for emissions reasons. As your ECU runs a cam phase sensor, it is of no extra cost or effort to do sequential. So no reason to not use it. This will stay a theoretical argument.

If you have trouble finding methanol compatible injectors, you might consider ethanol instead. It makes surprisingly little difference and ethanol compatible injectors are plently around. From a chemistry standpoint, any injector that is fully ethanol compatible should also last with methanol. Worst case buy one, soak in in Methanol in a jar and try if it still works once a month.

If you go for the 350 range, you need huge injectors anyhow. For 350HP on petrol alone you already need 650cc injectors. On e85 more like a 1000cc a minute and with methanol you are heading in the 1300cc/min direction. (Numbers just scaled up, not calculated and for a 4 cylinder engine) your intake valve is open for about 70% of the revolution with the intake stroke for a 270 deg cam. So once you injector duty cycle exceeds 70% you are injecting against a closed valve anyhow. It does not really matter anyhow.

If you want to maximize in cylinder charge cooling from methanol, you need in cylinder direct injection with those nice 150 bar injectors. No more valve wetting. Thing is you still need to carefully position them to minimize the spray hitting the surfaces in the cylinder. Any spray hitting the walls just cools the metal and not the air.
In one of the papers I linked in the literature section of this forum quantifies the effect of this internal cooling by comparing at which IAT a engine starts to knock running either direct injection of port injection. They employed gasoline and ethanol.

If the car is a daily driver, I'd seriously consider a dual fuel system. Run it on petrol and phae over to alcohol or e85 on boost (plus option water, if requiered). Ronin aka Frank Profera did such a dual fuel system with his 680HP Lotus Exige (the Ronin RS 211) running a turbocharged 1.8l 2ZZ-GE, it's "original" engine. He uses isopropanol in a secondary injection system. Ethanol would work as well, but isopropanol is easier to come by in the US in any drug store.
Pothole along on 95 octane and inject the 110 stuff on demand. A little 10l fuel cell should do.

[parmas]

According to Dave Walker, owner of Emerald ECU and very exerpeicned dyno operator says no. It makes little to no difference in power. He tried it. It is mainly done for emissions reasons. As your ECU runs a cam phase sensor, it is of no extra cost or effort to do sequential. So no reason to not use it. This will stay a theoretical argument.

The term "little" could be interpreted wrong. The question is, is it worth full sequential in terms of power and efficiency?

If you have trouble finding methanol compatible injectors, you might consider ethanol instead. It makes surprisingly little difference and ethanol compatible injectors are plently around. From a chemistry standpoint, any injector that is fully ethanol compatible should also last with methanol. Worst case buy one, soak in in Methanol in a jar and try if it still works once a month.

Could do but a little risky in reality.

If you go for the 350 range, you need huge injectors anyhow. For 350HP on petrol alone you already need 650cc injectors. On e85 more like a 1000cc a minute and with methanol you are heading in the 1300cc/min direction. (Numbers just scaled up, not calculated and for a 4 cylinder engine) your intake valve is open for about 70% of the revolution with the intake stroke for a 270 deg cam. So once you injector duty cycle exceeds 70% you are injecting against a closed valve anyhow. It does not really matter anyhow.

You are right but you are forgetting that if I go direct port injection I will be working with 8Injectors. Four will be used as pump fuel and four will be water/methanol. Injectors flowrates will change drastically. Also I am planning running a high pressure pump (trying to find 300psi+)

If you want to maximize in cylinder charge cooling from methanol, you need in cylinder direct injection with those nice 150 bar injectors. No more valve wetting. Thing is you still need to carefully position them to minimize the spray hitting the surfaces in the cylinder. Any spray hitting the walls just cools the metal and not the air.
In one of the papers I linked in the literature section of this forum quantifies the effect of this internal cooling by comparing at which IAT a engine starts to knock running either direct injection of port injection. They employed gasoline and ethanol.

I believe 150Bar is above and beyond :)

If the car is a daily driver, I'd seriously consider a dual fuel system. Run it on petrol and phae over to alcohol or e85 on boost (plus option water, if requiered). Ronin aka Frank Profera did such a dual fuel system with his 680HP Lotus Exige (the Ronin RS 211) running a turbocharged 1.8l 2ZZ-GE, it's "original" engine. He uses isopropanol in a secondary injection system. Ethanol would work as well, but isopropanol is easier to come by in the US in any drug store.
Pothole along on 95 octane and inject the 110 stuff on demand. A little 10l fuel cell should do.

That's the Aim :)


What do you think of the solenoids attached ? Using one per nozzle connected to ecu with a fuel basemap according boost with air temp correction?

[rotrex]

Wiithout a data sheet hard to say if they are good as a injector valve. With a dual injection system you can skip the water and use normal fuel injectors. Add charge or air to air cooling. It will gain serious power.

[parmas]

I dont have a datasheet but surely better than an always ON system.

I am not interested in charge / inter coolers for now...

[parmas]

Rotrex what do you think about these?

https://www.google.com.mt/url?sa=t&source=web&rct=j&url=http://www.parker.com/literature/Fluid%2520Control%2520Division%2520Europ e/5210UKLow.pdf&ved=0ahUKEwiOvMvb4NDMAhULfxoKHTYkB2oQFgg aMAA&usg=AFQjCNHG_HtoSHTXOKAXEuX2dBS_XVEWEw&sig2=dYSBXVYgtfW8oAQRHXrdaQ

[rotrex]

there are no specifications for switch times.
the closed thing I can spontaneously come up with is Aquamist's current valve.
But even this will be rather on the slow side for sequential port injection.
The next thing is that you then have a bit of pipe to the jet. With a ID of 1.5mm it has a inner volume of 18µl per cm or 180µl per 10cm.
The fluid volume injected per cycle will be of a similar order. This could or could not lead to issues forming a nice cloud out of a remote nozzle at the right time.

[parmas]

The article below made me believe that infact sequential injection may not yield any benefit over high rpm and wide open throttle

http://www.sdsefi.com/techseq.htm

[rotrex]

found the same link and actually though I posted it here??
Here is an other interesting read with some quotes from known companies.
http://forums.holley.com/showthread.php?2575-Sequential-EFI-vs-Bank-to-Bank-amp-Paired-EFI

[parmas]

found the same link and actually though I posted it here??
Here is an other interesting read with some quotes from known companies.
http://forums.holley.com/showthread.php?2575-Sequential-EFI-vs-Bank-to-Bank-amp-Paired-EFI

BEST Notes

1. Sequential injection will always get slightly better fuel economy and cleaner exhaust emissions. Also, according to page 152 of "How to Tune and Modify Engine Management Systems" (book by Jeff Hartman), sequential injection always gains power at peak torque and at peak horsepower.

2. With a highly atomized mix in the port, at intake valve opening, the lighter droplets of fuel will be partly blown back up the port [intake port reversion]. This is caused by the residual exhaust pressure [overlap period] still residing in the combustion chamber. Some of this reverted mixture will adhere to port walls and condense. This puddling fuel may find its way home, on the next intake cycle, but it will cause cycle-to-cycle air/fuel ratio variances.

3. At 8000 RPM the intake valve is opening and closing at 66 times a sec. and is only open for an average of 9 Mil/Sec.

4. "Fuel injected directly onto the intake valve yields a significantly better engine response"

5. Nozzle location should be as parallel to the airflow stream as possible
not be more than 45 degrees, although it can be less.

6. On the other hand, in theory, high-idle vacuum generated by mild stock engines permits placing the injector farther upstream without significant low-speed driveability degradation.

7. Moving the injector farther away from the valve allows more time for the air/fuel to atomize properly and remain in suspension when air velocity comes up at high rpm. This should improve peak power but-because of poor low-rpm velocity-at the expense of idle quality

8. On a 1,000hp engine, the injectors were originally located 7 inches back from the valves. Doubling this distance to 14 inches was worth 50 hp on top, a 5 percent gain-but "it wouldn't idle below 1,600 rpm.

9. A decent compromise for a hot-rod engine is to locate the nozzle about 1-2 inches upstream from the manifold flange to give atomization a chance, positioning the fuel rail at the best angle you can get away with and still package the harness and fuel rails

[rotrex]

so for you, you could leave the injectors for the petrol at the OEM location.
Install a second set of methanol injectors further upstream and/or pre turbo.
Run a 10l fuel cell with own pump etc. for the methanol or ethanol.
Red Victor, a 2000HP+ street legal drag car running methanol, injects both before and after the turbos.
Add water nozzles whee you deem them useful and skip the sequential injection.

If you need to inject all your fuel within those 9ms, you need really big injectors.

Question is if this is really worth the trouble for the HP goals you have?
As your car is FWD with limited tyre width you will likely already be at the traction limit as is.

[parmas]

so for you, you could leave the injectors for the petrol at the OEM location.
Install a second set of methanol injectors further upstream and/or pre turbo.
Run a 10l fuel cell with own pump etc. for the methanol or ethanol.
Red Victor, a 2000HP+ street legal drag car running methanol, injects both before and after the turbos.
Add water nozzles whee you deem them useful and skip the sequential injection.

If you need to inject all your fuel within those 9ms, you need really big injectors.

Question is if this is really worth the trouble for the HP goals you have?
As your car is FWD with limited tyre width you will likely already be at the traction limit as is.

The present plan :

- 4 nozzles (working on sizes) into the intake plenum runners running a 50/50 mix of water/methanol. The car is street driven and could happen to stay parked hours in the sun. A 10ltr pure methanol tank in the trunk would be actually dangerous especially in direct sunlight moments.

- The engine will be a 12:1 compression so injecting at low boost is critical. Engine is targeted to reach 330bhp @ 14psi. Actually preparing the engine for 400bhp+ but the turbo is the limiting factor.

- The water/methanol injection is going to be used mainly for high compression safety even at low boost. Second is to use the WM50 system to increase efficiency of the engine by set it as a base fuel @ wide open throttle. Target is to reach current power level with the least possible boost.

- I saw FWD running high 8sec 1/4miles with 600bhp levels.... so why not shooting for 400bhp.

The question is would you prefer get to that level with More boost or More methanol ?

[rotrex]

at this CR level, you need both, boost and high octane methanol.

How do you handle the torque steer? Are you running a LSD?
It definitely sound like a exiting car to drive :-)
I had a 1989 Honda Civic Si while living in the US.

[parmas]

Preferably low boost + high octane for now.

The intension is not only fun but efficiency. The engine is intended to be more economical during light cruising and on very low boost compared to a new stock toyota engine. Also emissions should reduce dramatically with the high compression and water injection. VRT pass test will be the result.

Performance wise - I can only imagine the feeling WOT on 3rd gear will be. Intercooless + 6spd gearbox + LSd + high comp + ball bearing boost.... Well exquisite :)

[rotrex]

I operated my engine at a CR of 10.5 before. Low down torque and economy are better.
I went from 8l/100km to 10 l/100km just dropping CR.
On the positive side, tuning under boost became much easier and overall power in the power band from 4K to 7k rpm increased.

Under full boost, that little intake volume is irrelevant at 300l of air a second.

[parmas]

Air pressure is always better than compression. More Air is always equal to more power.

On street you want good acceleration from low to high rpms and a big turbo is no good for that. Smaller turbos will eventually loose air high rpm. You cannot have both best worlds.

The previous setup at 20 psi was nuts on street above 4krpm

[rotrex]

Here is a picture of my pistons running 4x 0.4mm C-type aquamist jets behind the fuel injectors.

Here is how it looked like right after popping off the head:
https://s19.postimg.org/fu9kg5xsj/IMG_3959_1.jpg (https://postimg.org/image/s8wcghpan/)

You can clearly see where the water/methanol injection from the direct port injection nozzles reduced carbon build up and cool the critical spots. it is pretty uniform and on both intake and exhaust side. this shows that the spray passes both the intake valve's rear and front. with the nozzles on top of the runners in the past did did not happen.

The spray followed pretty much the fuel spray with the bigger droplets hitting the piston and cylinder walls front and rear as they cannot make the turn back horizontal with the swirl.