Honda Power Unit Hardware & Software

[aleks_ader]

I am definitely not Arai-san. I am old enough to be his father.

Aha so you are his father. Gotcha!!! (sarcasm off)

[PlatinumZealot]

What does Wazari mean in Japanese? I guess it is not your real name Wazari.

[Wazari]

What does Wazari mean in Japanese? I guess it is not your real name Wazari.

Actually the word is waza-ari which loosely translated means almost perfect or almost a knock out. I just shortened to wazari for user name purposes. It's a scoring term most common used in judo. My real first name is Mitsuru.

[ringo]

I somewhat agree with heat being Honda PU's enemy. Heat from rotation and bearing surfaces off the compressor and turbine. Rotational equipment seem to have poorer efficiency when they are smaller as well.
The same heat issue ties back into their MGUH. I think it has a lower power thresholdhold, or service factor than the other engines.

[Brian Coat]

Ringo's remark made me think about the fundamental scale effects associated with challenge of turbo machinery and electric motors on a common shaft.

When designing and electric motor/generator, "smaller, faster" is often more effective (especially for power density) because an electric motor is fundamentally a machine for making/using torque. Very high efficiency can be achieved even at high rpm's.

When designing turbo machinery, bigger is usually better for efficiency due to Reynolds number effects and the ease of maintaining accuracy between components.

From this a pseudo-formula for trouble can easily be written.

High power density + lower efficiency = higher rejected heat + (buried package) = overheating

[Joseki]

http://en.f1i.com/news/36610-new-mclare ... 5-car.html

"As Eric says, our concept or our philosophy is carried over, but a completely new engine, right now, is under development," Arai added.



So they'll continue with a "size 0 power unit".

[trinidefender]

A theory that I have had in my brain (and I'm sure other people have thought of it too) that may be causing Honda problems is vibration. I'm not talking about vibration that most people are thinking of, I'm talking about resonance. Devices on a spinning shaft can be particularly susceptible to this. I'm wondering if at the top of the rpm range for the turbocharger/MGU-H it is running into resonance problems.

While this probably is not the cause as it should have been something caught in dyno testing, it did get me thinking. Then again dyno testing wasn't with the PU bolted into the car so that can change the resonance frequency of a part. The only reason that I am even thinking this may be an issue is because it seems to fit what has been said about vibration problems and connections constantly coming loose and seals rupturing.

A real world example of this phenomenon that I deal with is on the turbine engines in our helicopters. They have two shafts in them. One of the shafts is for the gas producer section (axial and centrifugal compressor, combustion chamber and first stage turbine) and the second shaft has the power (turbine that takes drive to the gearbox and rotor system). Neither shaft is mechanically linked together at all yet each shaft has its own rpm avoid range that we are not to stay in. When advancing the engine you advance it through this range quickly and smoothly and we have been warned not to stay there as the resonant frequencies that build up can destroy and engine.

[turbof1]

A theory that I have had in my brain (and I'm sure other people have thought of it too) that may be causing Honda problems is vibration. I'm not talking about vibration that most people are thinking of, I'm talking about resonance. Devices on a spinning shaft can be particularly susceptible to this. I'm wondering if at the top of the rpm range for the turbocharger/MGU-H it is running into resonance problems.

While this probably is not the cause as it should have been something caught in dyno testing, it did get me thinking. Then again dyno testing wasn't with the PU bolted into the car so that can change the resonance frequency of a part. The only reason that I am even thinking this may be an issue is because it seems to fit what has been said about vibration problems and connections constantly coming loose and seals rupturing.

A real world example of this phenomenon that I deal with is on the turbine engines in our helicopters. They have two shafts in them. One of the shafts is for the gas producer section (axial and centrifugal compressor, combustion chamber and first stage turbine) and the second shaft has the power (turbine that takes drive to the gearbox and rotor system). Neither shaft is mechanically linked together at all yet each shaft has its own rpm avoid range that we are not to stay in. When advancing the engine you advance it through this range quickly and smoothly and we have been warned not to stay there as the resonant frequencies that build up can destroy and engine.

Resonance like the Tacoma Narrows Bridge?

[trinidefender]

A theory that I have had in my brain (and I'm sure other people have thought of it too) that may be causing Honda problems is vibration. I'm not talking about vibration that most people are thinking of, I'm talking about resonance. Devices on a spinning shaft can be particularly susceptible to this. I'm wondering if at the top of the rpm range for the turbocharger/MGU-H it is running into resonance problems.

While this probably is not the cause as it should have been something caught in dyno testing, it did get me thinking. Then again dyno testing wasn't with the PU bolted into the car so that can change the resonance frequency of a part. The only reason that I am even thinking this may be an issue is because it seems to fit what has been said about vibration problems and connections constantly coming loose and seals rupturing.

A real world example of this phenomenon that I deal with is on the turbine engines in our helicopters. They have two shafts in them. One of the shafts is for the gas producer section (axial and centrifugal compressor, combustion chamber and first stage turbine) and the second shaft has the power (turbine that takes drive to the gearbox and rotor system). Neither shaft is mechanically linked together at all yet each shaft has its own rpm avoid range that we are not to stay in. When advancing the engine you advance it through this range quickly and smoothly and we have been warned not to stay there as the resonant frequencies that build up can destroy and engine.

Resonance like the Tacoma Narrows Bridge?

Yes I guess you can say so. I am by no means a vibration expert or even anything close so I could have been using the completely wrong word. I do however know that spinning shafts tend to end up with a rpm range that should be avoided for any extended period of time as it can damage bearings and other things.

Thinking again I'm not even sure if resonance is the right word as from what I've read generally something has to stay at the resonance frequency for a little while for the vibrations to build up.

For those more knowledgable than me, would the turbocharger/MGU-H shaft speed be changing to much for this to be a problem?

[turbof1]

A theory that I have had in my brain (and I'm sure other people have thought of it too) that may be causing Honda problems is vibration. I'm not talking about vibration that most people are thinking of, I'm talking about resonance. Devices on a spinning shaft can be particularly susceptible to this. I'm wondering if at the top of the rpm range for the turbocharger/MGU-H it is running into resonance problems.

While this probably is not the cause as it should have been something caught in dyno testing, it did get me thinking. Then again dyno testing wasn't with the PU bolted into the car so that can change the resonance frequency of a part. The only reason that I am even thinking this may be an issue is because it seems to fit what has been said about vibration problems and connections constantly coming loose and seals rupturing.

A real world example of this phenomenon that I deal with is on the turbine engines in our helicopters. They have two shafts in them. One of the shafts is for the gas producer section (axial and centrifugal compressor, combustion chamber and first stage turbine) and the second shaft has the power (turbine that takes drive to the gearbox and rotor system). Neither shaft is mechanically linked together at all yet each shaft has its own rpm avoid range that we are not to stay in. When advancing the engine you advance it through this range quickly and smoothly and we have been warned not to stay there as the resonant frequencies that build up can destroy and engine.

Resonance like the Tacoma Narrows Bridge?

Yes I guess you can say so. I am by no means a vibration expert or even anything close so I could have been using the completely wrong word. I do however know that spinning shafts tend to end up with a rpm range that should be avoided for any extended period of time as it can damage bearings and other things.

Thinking again I'm not even sure if resonance is the right word as from what I've read generally something has to stay ipat the resonance frequency for a little while for the vibrations to build up.

For those more knowledgable than me, would the turbocharger/MGU-H shaft speed be changing to much for this to be a problem?

Looking into the Tacoma Narrows Bridge case, I think the words you MIGHT be looking for, is aero elasticity flutter. It might be a problem if the turbo varies too much in rpm. That's actually one of the problems of the Honda Turbo: the mgu-h cannot sufficiently generate enough energy to keep the turbo spooled up at all times.

It's a combination of aerodynamics and resonance.

[trinidefender]

Resonance like the Tacoma Narrows Bridge?

Yes I guess you can say so. I am by no means a vibration expert or even anything close so I could have been using the completely wrong word. I do however know that spinning shafts tend to end up with a rpm range that should be avoided for any extended period of time as it can damage bearings and other things.

Thinking again I'm not even sure if resonance is the right word as from what I've read generally something has to stay ipat the resonance frequency for a little while for the vibrations to build up.

For those more knowledgable than me, would the turbocharger/MGU-H shaft speed be changing to much for this to be a problem?

Looking into the Tacoma Narrows Bridge case, I think the words you MIGHT be looking for, is aero elasticity flutter. It might be a problem if the turbo varies too much in rpm. That's actually one of the problems of the Honda Turbo: the mgu-h cannot sufficiently generate enough energy to keep the turbo spooled up at all times.

It's a combination of aerodynamics and resonance.

Actually I don't think that's the word I am looking for. What I am talking about is shaft vibrations. These aren't vibrations caused by airflow though the compressor or turbine. This is purely as a result of vibrations caused in spinning object. Hence I related it to the gas turbines in our helicopters. There is a percentage range of rpm avoid for any extended period of time for each shaft. Increasing and decreasing rpm of the shafts too often and rapidly is generally not good for any turbine but that is for reasons other than this form of vibration.

On a separate topic I never bought into the idea that these turbochargers are always designed to run at one rpm. If you take one look at a centrifugal compressor graph you will understand why. When the engineers designed the ICE they would have set goals for target AFR's (air fuel ratios) at different throttle loads, rpm's etc. that means as these conditions change the compressor will have to increase and decrease rpm to maintain the correct AFR's. A further point being that if the MGU-H has the turbocharger shaft spinning very fast at low throttle loads then there likely will have to be some throttling involved the reduce air mass flow through the ICE. This creates 2 problems: 1. It is a complete waste of energy, why throttle something reducing VE (volumetric all efficiency) when you have the ability to slow the turbocharger and reduce electrical energy consumption and 2. At high PR (pressure ratios) in the compressor vs low air mass flows you will guaranteed to get horrible compressor stalls. There are certain things an engineer can do to increase the operating range of a centrifugal compressor like shrouded ports however these are not ideal and hurt the maximum efficiency of the compressor.

"That's actually one of the problems of the Honda Turbo: the mgu-h cannot sufficiently generate enough energy to keep the turbo spooled up at all times." This was never confirmed. Yes you can hear the turbocharger slowing down but that can be intentional. Doesn't mean that the turbocharger is running any slower than it is supposed to. Also I am sure that sometimes Honda may feel that some energy save on the compressor at long periods off throttle can be better used put into the MGU-K. This is where deployment strategy comes I to play.

[wuzak]

Resonance like the Tacoma Narrows Bridge?

Yes I guess you can say so. I am by no means a vibration expert or even anything close so I could have been using the completely wrong word. I do however know that spinning shafts tend to end up with a rpm range that should be avoided for any extended period of time as it can damage bearings and other things.

Thinking again I'm not even sure if resonance is the right word as from what I've read generally something has to stay ipat the resonance frequency for a little while for the vibrations to build up.

For those more knowledgable than me, would the turbocharger/MGU-H shaft speed be changing to much for this to be a problem?

Looking into the Tacoma Narrows Bridge case, I think the words you MIGHT be looking for, is aero elasticity flutter. It might be a problem if the turbo varies too much in rpm. That's actually one of the problems of the Honda Turbo: the mgu-h cannot sufficiently generate enough energy to keep the turbo spooled up at all times.

It's a combination of aerodynamics and resonance.

Resonance is the correct term for spinning shafts.

Resonant Frequency is the term for the speed at which vibrations in the shaft become very large.

[Facts Only]

Between 0rpm and say 100,000rpm (operating speed) the turbo will have to accelerate through 2 or 3 resonance events which can be very damaging to the turbo hence the turbo's being kept at high speed by the MGUH and not allowed to drop back down into these resoance speed. They will also try to tune the shaft dynamics so that the general operating speed is equidistant between two resoanance frequencies so it is as far away as possible from a reasonance and sustains the least amount of dmagae during normal running.

Balancing of these turbo systems is an absolute nightmare, believe me.

[trinidefender]

Between 0rpm and say 100,000rpm (operating speed) the turbo will have to accelerate through 2 or 3 resonance events which can be very damaging to the turbo hence the turbo's being kept at high speed by the MGUH and not allowed to drop back down into these resoance speed. They will also try to tune the shaft dynamics so that the general operating speed is equidistant between two resoanance frequencies so it is as far away as possible from a reasonance and sustains the least amount of dmagae during normal running.

Balancing of these turbo systems is an absolute nightmare, believe me.

I can imagine it must be a nightmare. When you also consider that the extra mass spinning in the MGU-H then things must get even more complicated. Is not also true that the longer you make the shaft the worse problems get.

It is my understanding that the vibration problems was one of the main obstacles that Mercedes had to overcome with their long turbocharger/MGU-H shaft and took a long time to really fine tune it to make the system reliable. I have to wonder if, as well as packaging reasons, Honda simply not having enough time to make such a system with such a long shaft reliable was one of the reasons that they decided to go with a shorter shaft and have the compressor in the V.

If resonance frequencies were the culprit would these not have been things that could have been fixed or at least made less of a problem with reliability fixes?

[turbof1]

Between 0rpm and say 100,000rpm (operating speed) the turbo will have to accelerate through 2 or 3 resonance events which can be very damaging to the turbo hence the turbo's being kept at high speed by the MGUH and not allowed to drop back down into these resoance speed. They will also try to tune the shaft dynamics so that the general operating speed is equidistant between two resoanance frequencies so it is as far away as possible from a reasonance and sustains the least amount of dmagae during normal running.

Balancing of these turbo systems is an absolute nightmare, believe me.

I can imagine it must be a nightmare. When you also consider that the extra mass spinning in the MGU-H then things must get even more complicated. Is not also true that the longer you make the shaft the worse problems get.

It is my understanding that the vibration problems was one of the main obstacles that Mercedes had to overcome with their long turbocharger/MGU-H shaft and took a long time to really fine tune it to make the system reliable. I have to wonder if, as well as packaging reasons, Honda simply not having enough time to make such a system with such a long shaft reliable was one of the reasons that they decided to go with a shorter shaft and have the compressor in the V.

If resonance frequencies were the culprit would these not have been things that could have been fixed or at least made less of a problem with reliability fixes?

It'll probably have been on everybody's list concerning biggest obstacles. Mercedes will probably will have made its life a bit more miserable though by including different temperatures and other vibrations in the V.

And yes, Honda only was able to develop the pu for a little bit more then a year. The others had 4.