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]

Originally Posted by 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

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]

Originally Posted by rotrex

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]

Originally Posted by 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.

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...