600/620 hp from the engine plus 160 from ERS ( 33 sec/lap)Chuckjr wrote:How much horsepower is the electric motor putting to the wheels vs how much power is the engine? Wouldn't that be critical in determining if it should be used for spooling the turbo or spinning the wheels? Im sorry if that's a dumb question.
It could very well be used as a driveability thing. The torque output of an ICE engine very roughly follows the gas pedal input but is actually quite non linear, especially in transient situations where you have lag from the combustion response, the engine inertia and turbo inertia. The MGU-K unit could be used to even out these non linearites and account for lag in engine response so that the drivers pedal position is more closely related to a torque demand.tuj wrote:Ok, so let's assume Ringo is right and the teams use the MGU-K to accelerate initially. The argument is instant power and torque, right? Well at low-rpms, transitioning from braking to acceleration, you want the *most gentle* torque curve possible as the driver tips into the throttle so the wheels don't spin.
Imagine if you hit the KERS button last year mid-corner....
It doesn't make sense. The MGU-K will be used in gears when the wheels are not traction-limited, ie. probably 3rd and higher. The MGU-H will keep the turbo spooled and the torque curve will be quite flat.
So you want to label the MGUK as being a caveman motor that has no speed or torque control, yet you will lable the MGUH as a delicate sugical scappel that will finesse a turbine in any transient phase?tuj wrote:Ok, so let's assume Ringo is right and the teams use the MGU-K to accelerate initially. The argument is instant power and torque, right? Well at low-rpms, transitioning from braking to acceleration, you want the *most gentle* torque curve possible as the driver tips into the throttle so the wheels don't spin.
Imagine if you hit the KERS button last year mid-corner....
It doesn't make sense. The MGU-K will be used in gears when the wheels are not traction-limited, ie. probably 3rd and higher. The MGU-H will keep the turbo spooled and the torque curve will be quite flat.
I don't get what exactly signal you take from the alternator? Anyway, I think what you describe would be a: quite easily detected and b: not really reliable because unless you are comparing the front and the rear wheelspeeds its very very difficult to judge wheel slip to the accuracy required for a traction control system. You need better than 1% accuracy for that.tuj wrote:Tim, I have speculated that this was RBR's 'secret' technology. My pure conjecture is that they were taking the signal from the alternator, which was directly tied to crank and (with the ECU knowing the gear and ratio) the wheelspeed. When excess wheel-speed was detected (assuming say a deviation from a planned ideal torque curve with perfect traction), the harvesting kicked in for a very brief period, slowing the engine, and therefore being a form of TC.
As to why Webber still sucked (relatively speaking) with the same car, I chalk it up to the fact that both driver could not drive the active-suspension FW14B either, only Mansell could.
In any case, I don't see how greatness alone could buy Vettel 2sec/lap over his competitors. Something else was going on with the car.
Webber's problem was never the power delivery, it was the stupidly fragile tires not inspiring confidence and allowing a driver to actually race at 100% for the entire race.tuj wrote:
As to why Webber still sucked (relatively speaking) with the same car, I chalk it up to the fact that both driver could not drive the active-suspension FW14B either, only Mansell could.
In any case, I don't see how greatness alone could buy Vettel 2sec/lap over his competitors. Something else was going on with the car.
ringo wrote:we are talking fractions of a second here, and yes it will do something for lag. Add 160 hp instantly to any engine, you would have no care in the world about spooling below a certain point. That engine will be up to high revs in no time with that additional horsepower.
5000rpm was an arbitrary number, i don't know how these engines will operate. But my point still stands, MGUK can be used when the engine is off boost. The driver will get an instant response.
MGUH spinning a turbine wont. There will be a lag with compressing the air, routing it through the intercooler, then up to the throttles then into the cylinders before you get that power down.
There is no way that will be quicker than an electric signal going to a motor couple to a drivetrain.
wuzak wrote:
- You won't have 160hp at low rpm from the MGU-K. Simple fact is that it is geared to the crankshaft with a fixed ratio. So you may have 90hp at your low rpms.
You don't know the motor's characteristic, so you cannot make that assumption. You can have full horsepower of the motor at low rpms. It's a motor not an engine. In fact motors usually start out with ridiculous amounts of torque at low speeds with steady power right up to rated speed. So your point may not be valid. But look into it anyway as we don't know the motor characteristic.wuzak wrote:
- You won't have 160hp at low rpm from the MGU-K. Simple fact is that it is geared to the crankshaft with a fixed ratio. So you may have 90hp at your low rpms.
What is SFA? see above regarding the MGUK power. I think it will deliver all 160hp as the engineers decide. The motor speed has no bearing on the power input from the batteries. It wont take seconds, it will be fractions of a second. It's all dependent on the load on the engine. looking at the fuel limit, i don't expect to see very huge turbos like in the past.[*]The engine and MGU-K have to accelerate the car. Since the engine is off-boost, it is making sweet FA power. So SFA + a proportion of the MGU-K is not much power. It will take seconds to get the engine to a position where it will be making meaningful boost.
What do you mean by oversized exactly? I don't think these engines can be considered conventional, so it's hard to use anything as a benchmark in terms of turbine size. I'm still of the mind that they will be ultra responsive, and it's only in situations where the load is high and the car is probably in the wrong gear will we see a lot of lag.[*]The turbine is oversize. It will take longer to get this turbo on boost than a conventional one with small turbines.
you are looking on making boost as a goal, which to me is arbitrary, as the big picture is moving the car down the track. I am looking on the overall goal, putting up to 160hp on the wheels instantly by pressing a throttle pedal when the engine is not up to it at that moment in time.[*]The MGU-H only has to spin the turbo. Much less inertia in that, wouldn't you agree? So to get up to maximum boost would take much less time than to accelerate the car. In any case, full boost won't be required until 10,500rpm and by then, hopefully, the exhaust energy is more than enough to drive the turbo - and even allow energy recovery.
That's all too much guess work, you need to look at the diameter of the piping and heat exchanger design. It's difficult to guess that.[*]How much lag in a turbo system through the ducting? I'm not sure what speed the air goes through. Let's say 50m/s. If you have 2m of ducting, that is 0.04s required to get from the compressor to the valve. Doubt that the driver would really sense that. Now, if they use a liquid:air intercooler, the distance is going to be about 0.5m. So the time is down to 0.01s. Can the carand engine accelerate up to speed in that time on one half rat power?
I as well, but i don't see a heavy dependence on the MGUH, it's just not going react as quickly. It's nice to think of in terms of technical complexity, but i don't think it's as straight forward as just engaging MGUK when the engine is off boost.[*]I have no doubt that the MGU-K will support the acceleration of the car. I also have no doubt that the MGU-H will spin the turbo when there is insufficient exhaust energy to drive it.[/list]
From the rules:ringo wrote:You don't know the motor's characteristic, so you cannot make that assumption. You can have full horsepower of the motor at low rpms. It's a motor not an engine. In fact motors usually start out with ridiculous amounts of torque at low speeds with steady power right up to rated speed. So your point may not be valid. But look into it anyway as we don't know the motor characteristic.wuzak wrote:
- You won't have 160hp at low rpm from the MGU-K. Simple fact is that it is geared to the crankshaft with a fixed ratio. So you may have 90hp at your low rpms.
SFA = sweet f**k allringo wrote:What is SFA? see above regarding the MGUK power. I think it will deliver all 160hp as the engineers decide. The motor speed has no bearing on the power input from the batteries. It wont take seconds, it will be fractions of a second. It's all dependent on the load on the engine. looking at the fuel limit, i don't expect to see very huge turbos like in the past.[*]The engine and MGU-K have to accelerate the car. Since the engine is off-boost, it is making sweet FA power. So SFA + a proportion of the MGU-K is not much power. It will take seconds to get the engine to a position where it will be making meaningful boost.
Making boost is obviously the goal - you want to get the engine out of its off boost/lag condition. Making boost early and without lag will make the whole car more responsive and move down the track faster.ringo wrote:you are looking on making boost as a goal, which to me is arbitrary, as the big picture is moving the car down the track. I am looking on the overall goal, putting up to 160hp on the wheels instantly by pressing a throttle pedal when the engine is not up to it at that moment in time.[*]The MGU-H only has to spin the turbo. Much less inertia in that, wouldn't you agree? So to get up to maximum boost would take much less time than to accelerate the car. In any case, full boost won't be required until 10,500rpm and by then, hopefully, the exhaust energy is more than enough to drive the turbo - and even allow energy recovery.
Yes, that is all conjecture. 50m/s is 1/6 of the speed of sound of air at normal temperature and pressure. Obviously it would be a bit different in warm compressed air.ringo wrote:That's all too much guess work, you need to look at the diameter of the piping and heat exchanger design. It's difficult to guess that.[*]How much lag in a turbo system through the ducting? I'm not sure what speed the air goes through. Let's say 50m/s. If you have 2m of ducting, that is 0.04s required to get from the compressor to the valve. Doubt that the driver would really sense that. Now, if they use a liquid:air intercooler, the distance is going to be about 0.5m. So the time is down to 0.01s. Can the carand engine accelerate up to speed in that time on one half rat power?
In normal turbo design the turbine is matched to the compressor. That is not the case here. The turbine will produce more power than the compressor needs when the engine is above an operating point where a normal turbine would be balanced. The turbine is physically larger than a normal turbo's and will have much more inertia.ringo wrote:What do you mean by oversized exactly? I don't think these engines can be considered conventional, so it's hard to use anything as a benchmark in terms of turbine size. I'm still of the mind that they will be ultra responsive, and it's only in situations where the load is high and the car is probably in the wrong gear will we see a lot of lag.[*]The turbine is oversize. It will take longer to get this turbo on boost than a conventional one with small turbines.
The MGU-H is the best solution to turbo lag. It will take a fraction of the time for the turbo to spin up and make boost (lag is the delay in that happening) than try to accelerate the whole car with the MGU-K and an off-boost ICE.ringo wrote:I as well, but i don't see a heavy dependence on the MGUH, it's just not going react as quickly. It's nice to think of in terms of technical complexity, but i don't think it's as straight forward as just engaging MGUK when the engine is off boost.[*]I have no doubt that the MGU-K will support the acceleration of the car. I also have no doubt that the MGU-H will spin the turbo when there is insufficient exhaust energy to drive it.[/list]