2014 intercooling

[ringo]

Your boost chart looks about right for 13.6 (you should use lambda - 13.6 is meaningless unless the fuel type is known) assuming 14.7 is stoich for the fuel used i.e. 0.925. I repeat "there is no way these engines are running 0.925". At that AFR 7.5% of the fuel is going out the exhaust and contributing nothing to the power.

I know more or less the fuel is very similar to what is marketed to street cars.

Honda RA128E in economy trim ran 0.98 and saw 32.2% thermal efficiency (272 g/kW.hr). If this engine was allowed to run in the current series with 100 kg/hr max fuel flow, it would make 368 kW or 490 bhp.

Economy trim was 70 degree intake air, with toluene fuel correct? What was the lower heating value of their fuel?

When run in its max power mode with lambda = 0.87 and intake air temp 40*C it's thermal efficiency was about 28.4% (307 g/kW.hr). With 100 kg/hr max fuel flow the "high power" version would make 324 kW or 432 bhp.
Which version would you run?

None of the above, as this type of fuel is not being used. So i cannot use honda's experiments with a different fuel to set the best practice for other kinds of fuel. I don't even think those numbers you posted are a good representation. It looks like something that you would have to observe. It's more empirical than anything else.

Honda made less power with the hotter intake air temperature. It's all in the article. As for the A:F this seems more tailored for the fuel properties.

What i think applies to these new engines in terms of temperatures and A:F is what we have typically in any turbocharged direct injection gasoline powered car.
Maybe a suped up Mitsubish evo is a good basis to work with.
Intercooler size and also intake air temps at similar power levels of 750 bhp should be a good indication.

[gruntguru]

Your boost chart looks about right for 13.6 (you should use lambda - 13.6 is meaningless unless the fuel type is known) assuming 14.7 is stoich for the fuel used i.e. 0.925. I repeat "there is no way these engines are running 0.925". At that AFR 7.5% of the fuel is going out the exhaust and contributing nothing to the power.

I know more or less the fuel is very similar to what is marketed to street cars.

Honda RA128E in economy trim ran 0.98 and saw 32.2% thermal efficiency (272 g/kW.hr). If this engine was allowed to run in the current series with 100 kg/hr max fuel flow, it would make 368 kW or 490 bhp.

Economy trim was 70 degree intake air, with toluene fuel correct? What was the lower heating value of their fuel?

It's all in the paper. 9817kCal/kg (41,074 kj/kg)

When run in its max power mode with lambda = 0.87 and intake air temp 40*C it's thermal efficiency was about 28.4% (307 g/kW.hr). With 100 kg/hr max fuel flow the "high power" version would make 324 kW or 432 bhp.
Which version would you run?

None of the above, as this type of fuel is not being used. So i cannot use honda's experiments with a different fuel to set the best practice for other kinds of fuel. I don't even think those numbers you posted are a good representation. It looks like something that you would have to observe. It's more empirical than anything else.

If you have any experience with tuning/mapping, you will know that fuel type makes little difference to AFR for best power and economy. As long as the fuel is not being used in excess for cooling, best power occurs around 0.9 and best economy occurs around 1.1 - 1.15

Honda made less power with the hotter intake air temperature. It's all in the article. As for the A:F this seems more tailored for the fuel properties.

THE HONDA ENGINE WAS RUNNING IN AN AIRFLOW LIMITED FORMULA. DISPLACEMENT AND BOOST PRESSURE WERE RESTRICTED. THE CURRENT FORMULA IS FUEL FLOW LIMITED. BESY EFFICIENCY = BEST POWER.

What i think applies to these new engines in terms of temperatures and A:F is what we have typically in any turbocharged direct injection gasoline powered car.
Maybe a suped up Mitsubish evo is a good basis to work with.

NO! FORGET EVERYTHING YOU LEARNED ABOUT MAKING MORE POWER. THIS IS DIFFERENT.

Intercooler size and also intake air temps at similar power levels of 750 bhp should be a good indication.

[trinidefender]

Yea max rpm, that was a typing error.

My A:F is set at 13.6:1 at all times in my calcs. boost is just pressure, it doesn't speak to the mass flow of the air. My intake temps are set at 40 degrees C. I don't buy into the learn burning gig as a performance advantage really. I don't really see where it will be used at racing speeds. Maybe in a situation where fuel is critical, or where engine push affects handling under braking or something.

Ringo why in the world would you use 13.6 A:F ratio. That is a thought process that goes out the window when port injection disappeared and direct injection was brought in. It was then further kicked down the road when the fuel limited formula was brought in.

Direct injection engines have a much lower use for running rich, they don't get the cooling effect of the air like in port injection. Yes it may help some for combustion stability but that is about it.

Now add to that a race formula where fuel flow is the limiting factor. Engineers get a certain fuel flow to play with and that's it. Therefore they will want to ensure that every drop if fuel is being burnt. This means it is pretty safe to assume that they will run at at least stoichiometric as if they burn below that they are essentially sending free power out of the exhaust.

A third reason is that a new age formula one engine can run with a larger more efficient compressor without having to worry about lag, that is handled by the MGU-H, unlike in road cars where they keep compressors generally smaller than they need to be for constant speed running efficiency (read; lowest temperature rise for a given pressure rise). This is done to reduce turbo spool up time as larger, heavier compressors add a lot of lag. Not applicable to F1 cars. The F1 car's turbo compressor can be sized for maximum efficiency which will probably make it bigger than a road cars turbo compressor. This reduces boost temps, hence lowering the chance of detonation and pre-ignition, further reducing the need for right A:F mixtures.

[PlatinumZealot]

I think 12.8 AFR is reasonable for power making.. but in this Fuel efficiency formula with direct in cyclinder injection... 13.6 might not be far off what is used... I mean remember these engines are said to be more efficient than anything on the road. Burning rich is never going give you good fuel efficiency.

[PlatinumZealot]

The honda turbo engines of the 1980's used a special blend of fuel, which would not atomise properly unless heated. That is why the Honda's made more power when they bypassed the itnercoolers and run the engine pig rich.The only way they were allowed to heat the fuel was wit the air in the intake tract itself. That is why the intercoolers were undersized or totally bypassed.

These modern engine have:

1. Petrol fuel
2. Direct injection.

There is no need to heat the fuel using hot air. You can now maximise power and efficiency by cooling the air as much as you can within certain drag limits of course.

[trinidefender]

I think 12.8 AFR is reasonable for power making.. but in this Fuel efficiency formula with direct in cyclinder injection... 13.6 might not be far off what is used... I mean remember these engines are said to be more efficient than anything on the road. Burning rich is never going give you good fuel efficiency.

Combustion with an A:F ratio of 13.6 will give a 7.5% reduction of power assuming that every last atom of fuel is burnt vs running at stoichiometric of 14.7 with the same assumptions of perfect combustion. If the engine would make 650 hp running at stoichiometric, reducing that A:F ratio to 13.6 (-7.5%) would make you lose almost 49 hp. Can you imagine any team doing that?

The simple fact of the matter is that teams are fuel limited, they will not pump in any more fuel than they cannot burn and with current regulations and tuebo sizing these engines could probably easily burn up to twice the fuel as currently used.

n smikle you are thinking along road car train of thoughts. What reason can you possibly come up with as to why any team would run an air:fuel ratio lower than stoichiometric?

[PlatinumZealot]

For fuel saving.
For power modes of course you will need to run richer.

However didn't want to go too deep in AFR's as I really have no clue what is run in current F1. I was more getting into the reasons why Honda ran their engine at higher air intake temperatures.

[trinidefender]

For fuel saving.
For power modes of course you will need to run richer.

However didn't want to go too deep in AFR's as I really have no clue what is run in current F1. I was more getting into the reasons why Honda ran their engine at higher air intake temperatures.

You seem to be greatly confused. Teams are already injecting the maximum of 100kg an hour (~27.8g/s).

Running a rich (any value richer than stoichiometric which is about 14.7:1, 13.6 being on the rich side) air:fuel ratio is only beneficial if your engine is limited by air flow as in road cars. Those engines are limited by throttle bodies, intake, volume of the cylinder etc on N/A cars and by air density (read it as boost pressure even thought that is technically incorrect) on turbocharged cars. In that situation those engines run as much air as they can run and then add in extra fuel on top of stoichiometric to try to increase heat and henceforth cylinder pressure.

In the 2014 F1 engines the manufacturers are fuel limited. As it stands now they all run the maximum fuel flow allowed. To get to the air:fuel ratio as you suggest means you have to cut airflow. All this does is reduce the amount of fuel being burnt which creates less heat which creates less pressure in the cylinder and pressure in the cylinder acting on the piston is what creates the torque on the crankshaft.

[PlatinumZealot]

For fuel saving.
For power modes of course you will need to run richer.

However didn't want to go too deep in AFR's as I really have no clue what is run in current F1. I was more getting into the reasons why Honda ran their engine at higher air intake temperatures.

You seem to be greatly confused. Teams are already injecting the maximum of 100kg an hour (~27.8g/s).

Running a rich (any value richer than stoichiometric which is about 14.7:1, 13.6 being on the rich side) air:fuel ratio is only beneficial if your engine is limited by air flow as in road cars. Those engines are limited by throttle bodies, intake, volume of the cylinder etc on N/A cars and by air density (read it as boost pressure even thought that is technically incorrect) on turbocharged cars. In that situation those engines run as much air as they can run and then add in extra fuel on top of stoichiometric to try to increase heat and henceforth cylinder pressure.

In the 2014 F1 engines the manufacturers are fuel limited. As it stands now they all run the maximum fuel flow allowed. To get to the air:fuel ratio as you suggest means you have to cut airflow. All this does is reduce the amount of fuel being burnt which creates less heat which creates less pressure in the cylinder and pressure in the cylinder acting on the piston is what creates the torque on the crankshaft.

Hold on there.... Haven't you head of something called lean burn?
With direct injection you can get away with running very lean ratios, especially if your piston crown is designed for it. You don't have to cut air flow as you say. You have control of your fuel injectors for this.
These days with direct injection you can run engines pretty lean without coming under threat of engine overheating.

[gruntguru]

Don't forget we are talking about a race engine at WOT. The rules allow 100 kg/hr of fuel so this is how much will be injected. It is the airflow that must be regulated to control mixture and the engine developers must find what air flow rate produces maximum power from that 100 kg/hr of fuel. Trinidefender is simply saying that to "run richer for power modes" as you suggested, the airflow would need to be reduced.

[riff_raff]

The power comes from the heat energy released from fuel combustion, and this process requires a specific combination of fuel and oxygen. Adding more air mass (oxygen) than is needed to fully combust the given amount of fuel will not result in more energy being released. However, it may be possible that the heat added to the excess air mass can be efficiently extracted by the exhaust turbine system.

[gruntguru]

. . . . Adding more air mass (oxygen) than is needed to fully combust the given amount of fuel will not result in more energy being released. However, it may be possible that the heat added to the excess air mass can be efficiently extracted by the exhaust turbine system.

The topic was whether the heat transferred to any excess air present in the cylinder is wasted and the point is no - the hot excess air helps drive the piston down as effectively as hot combustion products drive the piston down. There is no extra energy released and no extra energy extracted except that (potentially) less heat is lost to the walls thanks to the lower gas temperature.

[PhillipM]

Well, it doesn't because more heat is absorbed by the higher density air mass. And more energy is wasted getting that air to flow through the engine too.

[PlatinumZealot]

Don't forget we are talking about a race engine at WOT. The rules allow 100 kg/hr of fuel so this is how much will be injected. It is the airflow that must be regulated to control mixture and the engine developers must find what air flow rate produces maximum power from that 100 kg/hr of fuel. Trinidefender is simply saying that to "run richer for power modes" as you suggested, the airflow would need to be reduced.

I was just saying that the engines can run lean burn.
But back to WOT. You have differne't WOT due to the different engine maps. You were saying that 13.6 is too lean? Hey... maybe.. maybe not.. who can say... As I said before 12.5 or so is good for power in general street car tuning. But with these newfangled engines... supposed the combustion chamber is so efficiently designed? or supposed the injection is stratified and staged to make 13.6 give good enough power. (I didn't say the most power! but good fuel efficient power).

The fuel flow rate is capped at 100kg/hr beyond 10,000 rpm. But the teams run fuel maps that use less than this for regular racing pace and then there is a max power setting which uses all of the 100 kg/hr... it is quite reasonable to assume that the "normal" engine setting is a more lean fuel setting? No?

[wuzak]

Don't forget we are talking about a race engine at WOT. The rules allow 100 kg/hr of fuel so this is how much will be injected. It is the airflow that must be regulated to control mixture and the engine developers must find what air flow rate produces maximum power from that 100 kg/hr of fuel. Trinidefender is simply saying that to "run richer for power modes" as you suggested, the airflow would need to be reduced.

You were saying that 13.6 is too lean?

Grunt was saying that 13.6 is too rich.