Mercedes Power Unit Hardware & Software

[Santozini]

Merc fuel tank vent feeds air into the compressor during qualifying Q3

Fuel tank is filled with hydrocarbon gases, most likely derived from the same race fuel (not a small volume 120 liters or so) with some pressure. This will give them the additional fuel volume for more power.

I do not believe this is legal.

Same here, that sounds illegal to me. May I ask where does this theory come from?

[dren]

It's illegal, yes.

[Thunder]

Now this bit from yesterdays Strategy Group Meeting is Interesting:

That's the first Time this comes up as more than just a rumour.

Measures will be taken to ensure that oil will not be used as fuel. In addition, only one specification of oil may be used for any given power unit during an event.

https://www.jamesallenonf1.com/2017/04/ ... est-talks/

[wuzak]

Now this bit from yesterdays Strategy Group Meeting is Interesting:

That's the first Time this comes up as more than just a rumour.

Measures will be taken to ensure that oil will not be used as fuel. In addition, only one specification of oil may be used for any given power unit during an event.

https://www.jamesallenonf1.com/2017/04/ ... est-talks/

I suspect this is just to appease Red Bull who are the ones that alleged that Mercedes were burning oil.

[J.A.W.]

Now this bit from yesterdays Strategy Group Meeting is Interesting:

That's the first Time this comes up as more than just a rumour.

Measures will be taken to ensure that oil will not be used as fuel. In addition, only one specification of oil may be used for any given power unit during an event.

https://www.jamesallenonf1.com/2017/04/ ... est-talks/

"Measures will be taken..."?

Seems a tad nebulous.. since 'measures' has a few meanings, some more technically exacting than others..

"Measures" meaning newly applied lube oil - volume/consumption-rate/allowable additives - reg's?
Or "measures" meaning exhaust probe 'sniffers'?

[PlatinumZealot]

It is easy to see.. Watch the oil tank levels over the race. Take AFR readings.. injector flow rates and pulses.. The "oil" either flows into the gas tank from the crank case.. or it flows into the intake tract. My theory is that there is a and extra chamber in the engine block with drilling to deliver the additive/fuel. It could be only a liter that is required to give you that 0.3 seconds of lap-time for a single qually lap or two.

[gruntguru]

I would think normal oil consumption for a race would be at least a few litres. The only way to stop useful/illegal additives getting into the combustion chamber is to ban them from the lubricant.

[godlameroso]

Apparently as much as 5 liters of oil are consumed in a race distance. And I thought my track car burned a lot of oil at a little less than a liter in 1,500km. 5 liters is essentially the entire sump of an average 4 banger, and most Mercedes road cars only take about 8 liters total.

[shady]

The delta in viscosity is pretty large with the oils used in an F1 engine. If youve seen it, its closer to water than conventional 5W-30

[godlameroso]

The delta in viscosity is pretty large with the oils used in an F1 engine. If youve seen it, its closer to water than conventional 5W-30

I understand using lighter, oil, like a 20, or even 15 weight, as it's oil flow and not so much viscosity that determines hydrodynamic lubrication. Having said that, an oil at operating temperature is pretty thin, also what sense is there in running a multi-grade oil in an F1 ICE? Is the oil not injected into the car at operating temperature or very close to it anyway?

For reference a 0 weight motor oil has a kinematic viscosity of ~45 centistokes at room temperature, way too thick for any engine, but better than ~75 cts of a 10w-30 at room temperature. A 30 weight at 100c has a kinematic viscosity of ~10 centistokes, much thinner than a 0 weight oil at room temperature.

[PhillipM]

It pretty much is 0wt oil.

[godlameroso]

It pretty much is 0wt oil.

I heard somewhere that these power units operate @ ~130c, so what is the KV of a 0wt @ that temperature? ~5-6cts?

*hmm after doing some more research, it seems it(f1 crank case oil at operating temperature) pretty much is the same viscosity as water at room temperature.

[63l8qrrfy6]

The delta in viscosity is pretty large with the oils used in an F1 engine. If youve seen it, its closer to water than conventional 5W-30

I understand using lighter, oil, like a 20, or even 15 weight, as it's oil flow and not so much viscosity that determines hydrodynamic lubrication. Having said that, an oil at operating temperature is pretty thin, also what sense is there in running a multi-grade oil in an F1 ICE? Is the oil not injected into the car at operating temperature or very close to it anyway?

For reference a 0 weight motor oil has a kinematic viscosity of ~45 centistokes at room temperature, way too thick for any engine, but better than ~75 cts of a 10w-30 at room temperature. A 30 weight at 100c has a kinematic viscosity of ~10 centistokes, much thinner than a 0 weight oil at room temperature.

I am afraid that is incorrect - oil viscosity is exactly what determines hydrodynamic lubrication. Oil flow is what carries heat away from the bearing, maintaining viscosity and implicitly - the oil film thickness.

130 C sounds about right for oil leaving bearings - around 120 C I think is the texbook design value.
Typically a very simplistic way of looking at a bearing is to calculate the Hersey number, estimate friction then estimate frictional power loss at a given speed. Then assume a 60-40 split between heat carried away by oil and heat conducted into metal. This, together with the pressure drop caused by bearing clearance gives you a good starting point to estimate oil supply requirements.

[godlameroso]

The delta in viscosity is pretty large with the oils used in an F1 engine. If youve seen it, its closer to water than conventional 5W-30

I understand using lighter, oil, like a 20, or even 15 weight, as it's oil flow and not so much viscosity that determines hydrodynamic lubrication. Having said that, an oil at operating temperature is pretty thin, also what sense is there in running a multi-grade oil in an F1 ICE? Is the oil not injected into the car at operating temperature or very close to it anyway?

For reference a 0 weight motor oil has a kinematic viscosity of ~45 centistokes at room temperature, way too thick for any engine, but better than ~75 cts of a 10w-30 at room temperature. A 30 weight at 100c has a kinematic viscosity of ~10 centistokes, much thinner than a 0 weight oil at room temperature.

I am afraid that is incorrect - oil viscosity is exactly what determines hydrodynamic lubrication. Oil flow is what carries heat away from the bearing, maintaining viscosity and implicitly - the oil film thickness.

130 C sounds about right for oil leaving bearings - around 120 C I think is the texbook design value.
Typically a very simplistic way of looking at a bearing is to calculate the Hersey number, estimate friction then estimate frictional power loss at a given speed. Then assume a 60-40 split between heat carried away by oil and heat conducted into metal. This, together with the pressure drop caused by bearing clearance gives you a good starting point to estimate oil supply requirements.

Are you sure about that? I know I'm just a humble wrench jockey so I could be wrong, the reason you don't want to floor the engine during start up is precisely because oil cannot flow well when it is so thick. I was under the impression that film strength is the last line of defense as far as lubrication is concerned, and viscosity and film strength are not necessarily the same things. And that anti-wear additives mean more as far as film strength is concerned than simple viscosity.

[63l8qrrfy6]

I understand using lighter, oil, like a 20, or even 15 weight, as it's oil flow and not so much viscosity that determines hydrodynamic lubrication. Having said that, an oil at operating temperature is pretty thin, also what sense is there in running a multi-grade oil in an F1 ICE? Is the oil not injected into the car at operating temperature or very close to it anyway?

For reference a 0 weight motor oil has a kinematic viscosity of ~45 centistokes at room temperature, way too thick for any engine, but better than ~75 cts of a 10w-30 at room temperature. A 30 weight at 100c has a kinematic viscosity of ~10 centistokes, much thinner than a 0 weight oil at room temperature.

I am afraid that is incorrect - oil viscosity is exactly what determines hydrodynamic lubrication. Oil flow is what carries heat away from the bearing, maintaining viscosity and implicitly - the oil film thickness.

130 C sounds about right for oil leaving bearings - around 120 C I think is the texbook design value.
Typically a very simplistic way of looking at a bearing is to calculate the Hersey number, estimate friction then estimate frictional power loss at a given speed. Then assume a 60-40 split between heat carried away by oil and heat conducted into metal. This, together with the pressure drop caused by bearing clearance gives you a good starting point to estimate oil supply requirements.

Are you sure about that? I know I'm just a humble wrench jockey so I could be wrong, the reason you don't want to floor the engine during start up is precisely because oil cannot flow well when it is so thick. I was under the impression that film strength is the last line of defense as far as lubrication is concerned, and viscosity and film strength are not necessarily the same things. And that anti-wear additives mean more as far as film strength is concerned than simple viscosity.

Very sure - no mass flow terms in reynold's equation.

The reason you don't floor it hot is because there is no oil whatsoever in the bearings. The pressure drop across the lube system is also high at low temp high viscosity so you risk blowing filters.

Other reasons for warming up the engine are related to the transient thermal effects such as pistons growing faster than the bores or exhaust manifolds heating up faster than the heads, etc.