RE: Electric Superchargers On The Way
Discussion
chuntington101 said:
peterperkins said:
What could be quite clever is have a three stage system.
With an electric motor in between the intake and exhaust side of a standard turbo coupled to the shaft.
A small 12V supercapacitor to store some energy for quick spin up.
Then you get a number of operating modes.
1) Electric turbo mode when motor provides power to spin up the compressor at low engine speed.
2) Electric recharge mode when say at crusing speed and exhaust drives turbo with electric motor extracting some power to recharge caps.
3) Under extreme engine load both exhaust and electric motor power the turbo giving max output.
Right I'm off to the patent office.
Why? i hate asking this question but sometines you have to. Modern VGT and sequential turbos are VERY effective and can give you boost from pretty much idle. Look that the BMW deisel turbo systems. also VGT is another option. this works by altering the AR of the turbine housing and thus making the turbo spool MUCH faster. once boost is reached the VGT open up the AR and allows the turbo to breath and not be a restiction. the above methods are cheap (ish) and CAN work independently of other systems (ie ECU). With an electric motor in between the intake and exhaust side of a standard turbo coupled to the shaft.
A small 12V supercapacitor to store some energy for quick spin up.
Then you get a number of operating modes.
1) Electric turbo mode when motor provides power to spin up the compressor at low engine speed.
2) Electric recharge mode when say at crusing speed and exhaust drives turbo with electric motor extracting some power to recharge caps.
3) Under extreme engine load both exhaust and electric motor power the turbo giving max output.
Right I'm off to the patent office.
in the futer when we are driving around with 72volt electronic systesm this should be a lot easier to do. i just dont see anyone getting 40bhp + out of an electric motor driving and supercharger with it at the moment. how long could a system like that last with current alternators? how many alternators would you need to get that kind of power?
dont get me wrong i think its a lovely idea, instant boost whenever you want, lower intake and under bonnet temps, compresors you can mount anywhere in the chassis.......
Chris.
Now no-one with any sense has a 10Kw alternator for just operating the starter motor!
This system is designed to operate when you set off and when you are cruising in traffic and need to accelerate quickly, used in conjunction with a turbo as with the Golf GT.
Yes VGT is an improvement, but this system is designed for the market of the likes of the Golf GT, higher volume systems, please correct me if I am wrong, but I believe the only Petrol production car using a VGT turbo is the 997 turbo?
Yes there are a lot of diesels using VGT, but diesel turbos and petrol tend to have a number of differences because of the different operating enviroment.
Lets put it this way, you still need for example 40bhp * time energy to operate the supercharger, I'm not trying to say this is a free energy system.
But what would you rather have the 40bhp coming off the crank and less power to the wheels or 40bhp coming off the battery leaving that extra available to drive with?
This is where the theory of an electric turbocharger comes into its own, as you have no load on the crank and can use the motor to spool up with low gas flow.
There are actually some additional benefits to this:
1. The motor can be used to regulate the speed of the turbocharger and remove the wastegate improving gas flow through the unit.
2. As a result the motor can be converted into a generator and recover more energy from the exhaust, possibly even replace the alternator.
3. This in turn reduces the drag on the crank improving output again.
However electric powered turbos have some significant technical challenges:
1. 50-60bhp 100-120 thousand rpm motor.
2. Temperature, turbo's get very hot.
But from a pure performance improvement the electric supercharger offers the extra power the motor generates, if indirectly.
annodomini2 said:
Starter motors pull upto about 10KW in car applications (bout 8bhp)
Now no-one with any sense has a 10Kw alternator for just operating the starter motor!
This system is designed to operate when you set off and when you are cruising in traffic and need to accelerate quickly, used in conjunction with a turbo as with the Golf GT.
Yes VGT is an improvement, but this system is designed for the market of the likes of the Golf GT, higher volume systems, please correct me if I am wrong, but I believe the only Petrol production car using a VGT turbo is the 997 turbo?
Yes there are a lot of diesels using VGT, but diesel turbos and petrol tend to have a number of differences because of the different operating enviroment.
Lets put it this way, you still need for example 40bhp * time energy to operate the supercharger, I'm not trying to say this is a free energy system.
But what would you rather have the 40bhp coming off the crank and less power to the wheels or 40bhp coming off the battery leaving that extra available to drive with?
This is where the theory of an electric turbocharger comes into its own, as you have no load on the crank and can use the motor to spool up with low gas flow.
There are actually some additional benefits to this:
1. The motor can be used to regulate the speed of the turbocharger and remove the wastegate improving gas flow through the unit.
2. As a result the motor can be converted into a generator and recover more energy from the exhaust, possibly even replace the alternator.
3. This in turn reduces the drag on the crank improving output again.
However electric powered turbos have some significant technical challenges:
1. 50-60bhp 100-120 thousand rpm motor.
2. Temperature, turbo's get very hot.
But from a pure performance improvement the electric supercharger offers the extra power the motor generates, if indirectly.
Hi torque motors really don't need to spin that fast to get a lot of power 60 brake is easilly attainable at 2500rpm for motors. I would add to the list of disadvantages that an electric motor no matter how small is going to be more expensive and heavier than a belt.Now no-one with any sense has a 10Kw alternator for just operating the starter motor!
This system is designed to operate when you set off and when you are cruising in traffic and need to accelerate quickly, used in conjunction with a turbo as with the Golf GT.
Yes VGT is an improvement, but this system is designed for the market of the likes of the Golf GT, higher volume systems, please correct me if I am wrong, but I believe the only Petrol production car using a VGT turbo is the 997 turbo?
Yes there are a lot of diesels using VGT, but diesel turbos and petrol tend to have a number of differences because of the different operating enviroment.
Lets put it this way, you still need for example 40bhp * time energy to operate the supercharger, I'm not trying to say this is a free energy system.
But what would you rather have the 40bhp coming off the crank and less power to the wheels or 40bhp coming off the battery leaving that extra available to drive with?
This is where the theory of an electric turbocharger comes into its own, as you have no load on the crank and can use the motor to spool up with low gas flow.
There are actually some additional benefits to this:
1. The motor can be used to regulate the speed of the turbocharger and remove the wastegate improving gas flow through the unit.
2. As a result the motor can be converted into a generator and recover more energy from the exhaust, possibly even replace the alternator.
3. This in turn reduces the drag on the crank improving output again.
However electric powered turbos have some significant technical challenges:
1. 50-60bhp 100-120 thousand rpm motor.
2. Temperature, turbo's get very hot.
But from a pure performance improvement the electric supercharger offers the extra power the motor generates, if indirectly.
ctallchris said:
annodomini2 said:
Starter motors pull upto about 10KW in car applications (bout 8bhp)
Now no-one with any sense has a 10Kw alternator for just operating the starter motor!
This system is designed to operate when you set off and when you are cruising in traffic and need to accelerate quickly, used in conjunction with a turbo as with the Golf GT.
Yes VGT is an improvement, but this system is designed for the market of the likes of the Golf GT, higher volume systems, please correct me if I am wrong, but I believe the only Petrol production car using a VGT turbo is the 997 turbo?
Yes there are a lot of diesels using VGT, but diesel turbos and petrol tend to have a number of differences because of the different operating enviroment.
Lets put it this way, you still need for example 40bhp * time energy to operate the supercharger, I'm not trying to say this is a free energy system.
But what would you rather have the 40bhp coming off the crank and less power to the wheels or 40bhp coming off the battery leaving that extra available to drive with?
This is where the theory of an electric turbocharger comes into its own, as you have no load on the crank and can use the motor to spool up with low gas flow.
There are actually some additional benefits to this:
1. The motor can be used to regulate the speed of the turbocharger and remove the wastegate improving gas flow through the unit.
2. As a result the motor can be converted into a generator and recover more energy from the exhaust, possibly even replace the alternator.
3. This in turn reduces the drag on the crank improving output again.
However electric powered turbos have some significant technical challenges:
1. 50-60bhp 100-120 thousand rpm motor.
2. Temperature, turbo's get very hot.
But from a pure performance improvement the electric supercharger offers the extra power the motor generates, if indirectly.
Hi torque motors really don't need to spin that fast to get a lot of power 60 brake is easilly attainable at 2500rpm for motors. I would add to the list of disadvantages that an electric motor no matter how small is going to be more expensive and heavier than a belt.Now no-one with any sense has a 10Kw alternator for just operating the starter motor!
This system is designed to operate when you set off and when you are cruising in traffic and need to accelerate quickly, used in conjunction with a turbo as with the Golf GT.
Yes VGT is an improvement, but this system is designed for the market of the likes of the Golf GT, higher volume systems, please correct me if I am wrong, but I believe the only Petrol production car using a VGT turbo is the 997 turbo?
Yes there are a lot of diesels using VGT, but diesel turbos and petrol tend to have a number of differences because of the different operating enviroment.
Lets put it this way, you still need for example 40bhp * time energy to operate the supercharger, I'm not trying to say this is a free energy system.
But what would you rather have the 40bhp coming off the crank and less power to the wheels or 40bhp coming off the battery leaving that extra available to drive with?
This is where the theory of an electric turbocharger comes into its own, as you have no load on the crank and can use the motor to spool up with low gas flow.
There are actually some additional benefits to this:
1. The motor can be used to regulate the speed of the turbocharger and remove the wastegate improving gas flow through the unit.
2. As a result the motor can be converted into a generator and recover more energy from the exhaust, possibly even replace the alternator.
3. This in turn reduces the drag on the crank improving output again.
However electric powered turbos have some significant technical challenges:
1. 50-60bhp 100-120 thousand rpm motor.
2. Temperature, turbo's get very hot.
But from a pure performance improvement the electric supercharger offers the extra power the motor generates, if indirectly.
But you would gain that 60bhp at the crank, whereas with a belt you will not as it is lost driving the supercharger. Off load though your fuel consumption would be slightly higher driving the alternator to recharge the battery.
For a turbocharger, which typically spin at up to 100,000-150,000rpm adding a gearbox makes balancing the turbine very complicated (adding the motor armature doesn't help)
ETA: Obviously if you flatten your battery doing this its not going to work!
Edited by annodomini2 on Friday 25th September 16:46
annodomini2 said:
True, at 2500rpm the supercharger would probably require a gearbox aswell.
But you would gain that 60bhp at the crank, whereas with a belt you will not as it is lost driving the supercharger. Off load though your fuel consumption would be slightly higher driving the alternator to recharge the battery.
For a turbocharger, which typically spin at up to 100,000-150,000rpm adding a gearbox makes balancing the turbine very complicated (adding the motor armature doesn't help)
ETA: Obviously if you flatten your battery doing this its not going to work!
Have you got an extra 0 in there 23,000 rpm is enough for the acceleration to tear a cd apart. 100,000 rpm would mean a 12 cm blade in a turbo would be travelling faster than the speed of sound.But you would gain that 60bhp at the crank, whereas with a belt you will not as it is lost driving the supercharger. Off load though your fuel consumption would be slightly higher driving the alternator to recharge the battery.
For a turbocharger, which typically spin at up to 100,000-150,000rpm adding a gearbox makes balancing the turbine very complicated (adding the motor armature doesn't help)
ETA: Obviously if you flatten your battery doing this its not going to work!
Edited by annodomini2 on Friday 25th September 16:46
annodomini21 said:
50-60bhp 100-120 thousand rpm motor.
2. Temperature, turbo's get very hot.
Its doesnt have to go that fast if sized correctly and the constant speed/speed demand from the electric motor means you run the compressor at a much higher adiabatic efficiency so the charge is cooler.2. Temperature, turbo's get very hot.
The heat wont be an issue, the bulk of the heat in a turbo is from the turbine generating the shaft torque, thats what the electric motor will so instead though. Hence its a supercharger.
Edited by JonnyVTEC on Friday 25th September 19:15
ctallchris said:
annodomini2 said:
True, at 2500rpm the supercharger would probably require a gearbox aswell.
But you would gain that 60bhp at the crank, whereas with a belt you will not as it is lost driving the supercharger. Off load though your fuel consumption would be slightly higher driving the alternator to recharge the battery.
For a turbocharger, which typically spin at up to 100,000-150,000rpm adding a gearbox makes balancing the turbine very complicated (adding the motor armature doesn't help)
ETA: Obviously if you flatten your battery doing this its not going to work!
Have you got an extra 0 in there 23,000 rpm is enough for the acceleration to tear a cd apart. 100,000 rpm would mean a 12 cm blade in a turbo would be travelling faster than the speed of sound.But you would gain that 60bhp at the crank, whereas with a belt you will not as it is lost driving the supercharger. Off load though your fuel consumption would be slightly higher driving the alternator to recharge the battery.
For a turbocharger, which typically spin at up to 100,000-150,000rpm adding a gearbox makes balancing the turbine very complicated (adding the motor armature doesn't help)
ETA: Obviously if you flatten your battery doing this its not going to work!
Edited by annodomini2 on Friday 25th September 16:46
12cm diameter or radius? Thats a bigger turbo than usual automotive stuff if radius and of course its metal not plastic which helps somewhat with dealing with the centrifugal loads.
Im not sure what you mean by a gearbox on a supercharger? Mechanical ones use pulley ratios and an electric one can run whatever speed you ask from it. Loads of boost low down is just what you want then decouple/idle it during cruise. Its similar to the Prius concept really, Atkinson cycle with the electric motor to give you the low end grunt back.
JonnyVTEC said:
ctallchris said:
annodomini2 said:
True, at 2500rpm the supercharger would probably require a gearbox aswell.
But you would gain that 60bhp at the crank, whereas with a belt you will not as it is lost driving the supercharger. Off load though your fuel consumption would be slightly higher driving the alternator to recharge the battery.
For a turbocharger, which typically spin at up to 100,000-150,000rpm adding a gearbox makes balancing the turbine very complicated (adding the motor armature doesn't help)
ETA: Obviously if you flatten your battery doing this its not going to work!
Have you got an extra 0 in there 23,000 rpm is enough for the acceleration to tear a cd apart. 100,000 rpm would mean a 12 cm blade in a turbo would be travelling faster than the speed of sound.But you would gain that 60bhp at the crank, whereas with a belt you will not as it is lost driving the supercharger. Off load though your fuel consumption would be slightly higher driving the alternator to recharge the battery.
For a turbocharger, which typically spin at up to 100,000-150,000rpm adding a gearbox makes balancing the turbine very complicated (adding the motor armature doesn't help)
ETA: Obviously if you flatten your battery doing this its not going to work!
Edited by annodomini2 on Friday 25th September 16:46
12cm diameter or radius? Thats a bigger turbo than usual automotive stuff if radius and of course its metal not plastic which helps somewhat with dealing with the centrifugal loads.
Im not sure what you mean by a gearbox on a supercharger? Mechanical ones use pulley ratios and an electric one can run whatever speed you ask from it. Loads of boost low down is just what you want then decouple/idle it during cruise. Its similar to the Prius concept really, Atkinson cycle with the electric motor to give you the low end grunt back.
so circumference = 0.05 * 2 * PI = 0.157m
Distance traveled by tips= 80,000 * 0.37 = 12566 m/mi = 209 m/s (/60)
Speed of sound = 340 m/s
still really really sodding fast!
JonnyVTEC said:
annodomini21 said:
50-60bhp 100-120 thousand rpm motor.
2. Temperature, turbo's get very hot.
Its doesnt have to go that fast if sized correctly and the constant speed/speed demand from the electric motor means you run the compressor at a much higher adiabatic efficiency so the charge is cooler.2. Temperature, turbo's get very hot.
The heat wont be an issue, the bulk of the heat in a turbo is from the turbine generating the shaft torque, thats what the electric motor will so instead though. Hence its a supercharger.
Edited by JonnyVTEC on Friday 25th September 19:15
Its still a turbocharger, with most of the work being performed by the exhaust gasses from the exhaust turbine, but with an electric motor to assist with spool up when off boost.
JonnyVTEC said:
Im not sure what you mean by a gearbox on a supercharger? Mechanical ones use pulley ratios and an electric one can run whatever speed you ask from it. Loads of boost low down is just what you want then decouple/idle it during cruise. Its similar to the Prius concept really, Atkinson cycle with the electric motor to give you the low end grunt back.
Depending on the design of the supercharger would determine the desired operating speed, but typically the speed of the supercharger is multiplied that of the engine so with say a 2:1 ratio on a a typical max rpm of 6000rpm the supercharger would be running at 12000rpm. if the same supercharger was used with the motor there would need to be a drive ratio of 4.8.My use of 'gearbox' could be misinterpreted of what I intended, there wouldn't be a need for multiple gears.
annodomini2 said:
JonnyVTEC said:
annodomini21 said:
50-60bhp 100-120 thousand rpm motor.
2. Temperature, turbo's get very hot.
Its doesnt have to go that fast if sized correctly and the constant speed/speed demand from the electric motor means you run the compressor at a much higher adiabatic efficiency so the charge is cooler.2. Temperature, turbo's get very hot.
The heat wont be an issue, the bulk of the heat in a turbo is from the turbine generating the shaft torque, thats what the electric motor will so instead though. Hence its a supercharger.
Edited by JonnyVTEC on Friday 25th September 19:15
Its still a turbocharger, with most of the work being performed by the exhaust gasses from the exhaust turbine, but with an electric motor to assist with spool up when off boost.
Thinking about this topic this weekend. The main problem i can see with a electric assisted turbocharge is weight. how much would a 20/30 ecen 40bhp eletric motor weigh? my pouint is that thats going to as alot of mass to the turbine wheel, shaft and comp. wheel. this is going to make the turbo massively slow to spool.
Also, and im not trying to be an *rse here, but whats the addvantage of using an electric motor to spool a turbo, thats then going to add NO additional power to the engine, when you could just attach the motor direct to the crank? then you can make instant power, like N2O, and then let the turbo spool whenever it wants. Also you have to remember that when an engine gose into boost the fueling demands go up and this reduces econamy of the engine.
as for VGT/VNT, they are only just starting to be used on Petrol engines as the demand has not ben there in the past. its only no when we want massive boost and instant spool up that the petrol powered comunity has forced manufactures to look into things like VGT.
Petrol and deisel applications are somewhat duifferent, but not that far appart! the intial consideration is heat. yes petrol motors will have higher EGTs than deisels. this MAY require alternative materials or more advanced cooling methods to be used. however the major advantage to petrol of deisel is the vast reduction in carbon deposits! this is what i have heard normally causes VGT failures on deisel engines. In fact i have even hear of some compaines shedualing turbo replacements as they brake that offten!
Other areas people can invetigate when trying to reduce spool up times on turbo'ed engines are the timing/ignition curves. alot can be made and lots in the mapping of the engine. this has probalby been where the major inprovements have been in the past 15years.
Cheers
Chris.
PS. Great thread. its good to hear everyones opinions on a subject like this.
Also, and im not trying to be an *rse here, but whats the addvantage of using an electric motor to spool a turbo, thats then going to add NO additional power to the engine, when you could just attach the motor direct to the crank? then you can make instant power, like N2O, and then let the turbo spool whenever it wants. Also you have to remember that when an engine gose into boost the fueling demands go up and this reduces econamy of the engine.
as for VGT/VNT, they are only just starting to be used on Petrol engines as the demand has not ben there in the past. its only no when we want massive boost and instant spool up that the petrol powered comunity has forced manufactures to look into things like VGT.
Petrol and deisel applications are somewhat duifferent, but not that far appart! the intial consideration is heat. yes petrol motors will have higher EGTs than deisels. this MAY require alternative materials or more advanced cooling methods to be used. however the major advantage to petrol of deisel is the vast reduction in carbon deposits! this is what i have heard normally causes VGT failures on deisel engines. In fact i have even hear of some compaines shedualing turbo replacements as they brake that offten!
Other areas people can invetigate when trying to reduce spool up times on turbo'ed engines are the timing/ignition curves. alot can be made and lots in the mapping of the engine. this has probalby been where the major inprovements have been in the past 15years.
Cheers
Chris.
PS. Great thread. its good to hear everyones opinions on a subject like this.
chuntington101 said:
Thinking about this topic this weekend. The main problem i can see with a electric assisted turbocharge is weight. how much would a 20/30 ecen 40bhp eletric motor weigh? my pouint is that thats going to as alot of mass to the turbine wheel, shaft and comp. wheel. this is going to make the turbo massively slow to spool.
Also, and im not trying to be an *rse here, but whats the addvantage of using an electric motor to spool a turbo, thats then going to add NO additional power to the engine, when you could just attach the motor direct to the crank? then you can make instant power, like N2O, and then let the turbo spool whenever it wants. Also you have to remember that when an engine gose into boost the fueling demands go up and this reduces econamy of the engine.
as for VGT/VNT, they are only just starting to be used on Petrol engines as the demand has not ben there in the past. its only no when we want massive boost and instant spool up that the petrol powered comunity has forced manufactures to look into things like VGT.
Petrol and deisel applications are somewhat duifferent, but not that far appart! the intial consideration is heat. yes petrol motors will have higher EGTs than deisels. this MAY require alternative materials or more advanced cooling methods to be used. however the major advantage to petrol of deisel is the vast reduction in carbon deposits! this is what i have heard normally causes VGT failures on deisel engines. In fact i have even hear of some compaines shedualing turbo replacements as they brake that offten!
Other areas people can invetigate when trying to reduce spool up times on turbo'ed engines are the timing/ignition curves. alot can be made and lots in the mapping of the engine. this has probalby been where the major inprovements have been in the past 15years.
Cheers
Chris.
PS. Great thread. its good to hear everyones opinions on a subject like this.
As you should be well aware BHP or KW rating of a motor is a function of rotational velocity, at lets say 100,000rpm the torque doesn't need to be very high to generate 40bhp, the motor would need to be brushless as I doubt there could be a brushed motor that could handle those kind of velocities without destroying brushes within a few minutes.Also, and im not trying to be an *rse here, but whats the addvantage of using an electric motor to spool a turbo, thats then going to add NO additional power to the engine, when you could just attach the motor direct to the crank? then you can make instant power, like N2O, and then let the turbo spool whenever it wants. Also you have to remember that when an engine gose into boost the fueling demands go up and this reduces econamy of the engine.
as for VGT/VNT, they are only just starting to be used on Petrol engines as the demand has not ben there in the past. its only no when we want massive boost and instant spool up that the petrol powered comunity has forced manufactures to look into things like VGT.
Petrol and deisel applications are somewhat duifferent, but not that far appart! the intial consideration is heat. yes petrol motors will have higher EGTs than deisels. this MAY require alternative materials or more advanced cooling methods to be used. however the major advantage to petrol of deisel is the vast reduction in carbon deposits! this is what i have heard normally causes VGT failures on deisel engines. In fact i have even hear of some compaines shedualing turbo replacements as they brake that offten!
Other areas people can invetigate when trying to reduce spool up times on turbo'ed engines are the timing/ignition curves. alot can be made and lots in the mapping of the engine. this has probalby been where the major inprovements have been in the past 15years.
Cheers
Chris.
PS. Great thread. its good to hear everyones opinions on a subject like this.
So a brushless dc motor would be required, permanent magnet is necessary otherwise you again end up with brushes on the armeture.
3Phase probably at this power level.
As torque is relatively low the key with the motor would not be weight as the field strength doesn't need to be that high, but frequency of the driver of the motor would need to be capable of something in the region of 1-2Mhz through power electronics.
Weight would add deficiencies into the system, but if the magnetic elements of the system were engineered into the structure of the spindle weight addition could be reduced. Possibly even eliminated.
The main benefit of this type of system is it allows the use of a much larger turbo on a much smaller engine without suffering drastic lag, yes this has a detriment to fuel economy when at full chat.
But in combination with one of the new variable compression designs at idle you could achieve close to normal small engine economy and power when required a true displacement on demand without having to move the extra elements of the engine which are not being used.
Fiat have just introduced fully programmable electro-hydraulic valve actuation on the Mito (see multiair), albeit on the inlet only, which will offer significant efficiency improvement as the limitations of camshafts and their profiles are eliminated.
The benefit would be you could have a 1.2 four pot producing ridiculous amounts of power and in general use have its inherent size and weight efficiencies. Albeit much more complex.
Yup the fuelling and timing accuracy has improved so much over the last 15years and these technologies will take it to the next level.
annodomini2 said:
chuntington101 said:
Thinking about this topic this weekend. The main problem i can see with a electric assisted turbocharge is weight. how much would a 20/30 ecen 40bhp eletric motor weigh? my pouint is that thats going to as alot of mass to the turbine wheel, shaft and comp. wheel. this is going to make the turbo massively slow to spool.
Also, and im not trying to be an *rse here, but whats the addvantage of using an electric motor to spool a turbo, thats then going to add NO additional power to the engine, when you could just attach the motor direct to the crank? then you can make instant power, like N2O, and then let the turbo spool whenever it wants. Also you have to remember that when an engine gose into boost the fueling demands go up and this reduces econamy of the engine.
as for VGT/VNT, they are only just starting to be used on Petrol engines as the demand has not ben there in the past. its only no when we want massive boost and instant spool up that the petrol powered comunity has forced manufactures to look into things like VGT.
Petrol and deisel applications are somewhat duifferent, but not that far appart! the intial consideration is heat. yes petrol motors will have higher EGTs than deisels. this MAY require alternative materials or more advanced cooling methods to be used. however the major advantage to petrol of deisel is the vast reduction in carbon deposits! this is what i have heard normally causes VGT failures on deisel engines. In fact i have even hear of some compaines shedualing turbo replacements as they brake that offten!
Other areas people can invetigate when trying to reduce spool up times on turbo'ed engines are the timing/ignition curves. alot can be made and lots in the mapping of the engine. this has probalby been where the major inprovements have been in the past 15years.
Cheers
Chris.
PS. Great thread. its good to hear everyones opinions on a subject like this.
As you should be well aware BHP or KW rating of a motor is a function of rotational velocity, at lets say 100,000rpm the torque doesn't need to be very high to generate 40bhp, the motor would need to be brushless as I doubt there could be a brushed motor that could handle those kind of velocities without destroying brushes within a few minutes.Also, and im not trying to be an *rse here, but whats the addvantage of using an electric motor to spool a turbo, thats then going to add NO additional power to the engine, when you could just attach the motor direct to the crank? then you can make instant power, like N2O, and then let the turbo spool whenever it wants. Also you have to remember that when an engine gose into boost the fueling demands go up and this reduces econamy of the engine.
as for VGT/VNT, they are only just starting to be used on Petrol engines as the demand has not ben there in the past. its only no when we want massive boost and instant spool up that the petrol powered comunity has forced manufactures to look into things like VGT.
Petrol and deisel applications are somewhat duifferent, but not that far appart! the intial consideration is heat. yes petrol motors will have higher EGTs than deisels. this MAY require alternative materials or more advanced cooling methods to be used. however the major advantage to petrol of deisel is the vast reduction in carbon deposits! this is what i have heard normally causes VGT failures on deisel engines. In fact i have even hear of some compaines shedualing turbo replacements as they brake that offten!
Other areas people can invetigate when trying to reduce spool up times on turbo'ed engines are the timing/ignition curves. alot can be made and lots in the mapping of the engine. this has probalby been where the major inprovements have been in the past 15years.
Cheers
Chris.
PS. Great thread. its good to hear everyones opinions on a subject like this.
So a brushless dc motor would be required, permanent magnet is necessary otherwise you again end up with brushes on the armeture.
3Phase probably at this power level.
As torque is relatively low the key with the motor would not be weight as the field strength doesn't need to be that high, but frequency of the driver of the motor would need to be capable of something in the region of 1-2Mhz through power electronics.
Weight would add deficiencies into the system, but if the magnetic elements of the system were engineered into the structure of the spindle weight addition could be reduced. Possibly even eliminated.
The main benefit of this type of system is it allows the use of a much larger turbo on a much smaller engine without suffering drastic lag, yes this has a detriment to fuel economy when at full chat.
But in combination with one of the new variable compression designs at idle you could achieve close to normal small engine economy and power when required a true displacement on demand without having to move the extra elements of the engine which are not being used.
Fiat have just introduced fully programmable electro-hydraulic valve actuation on the Mito (see multiair), albeit on the inlet only, which will offer significant efficiency improvement as the limitations of camshafts and their profiles are eliminated.
The benefit would be you could have a 1.2 four pot producing ridiculous amounts of power and in general use have its inherent size and weight efficiencies. Albeit much more complex.
Yup the fuelling and timing accuracy has improved so much over the last 15years and these technologies will take it to the next level.
i would like to see a power recovery system used on pertrol/deisel engines. i wonder how much power could be generated at say 3,000rpm on a 2.0ltr just form the heat in the exhaust....
Intresting times
Chris.
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