Posted: Sat Nov 26, 2011 8:01 am Post subject: Petrol engine turbos with solenoid control of wastegate?
I am sure I read of a new range of petrol engine turbos, maybe from Borg Warner, that use solely electronic control of the internal wastegate flap valves. I am now doubting my sanity as I can't find the reference again. Has anyone any info on this, I have always thought some sort of direct acting servo motor with PID control from the ECU would be superior to pneumatic control indirectly altering the wastegate from the ecu via a boost control valve. Thanks. _________________ Best regards,
CMW
Joined: 11 Sep 2006 Posts: 650 Location: London, England
Posted: Sat Nov 26, 2011 9:50 am Post subject:
The new Porsche fitment VNT turbo's use electrical solenoids to control the turbine housing vanes, but I've not seen any units that electrically control a wastegate. _________________ Sam Borgman
www.facebook.com/torquedevelopments www.tdi-plc.com www.rototest.com
I wonder why this hadn't been done years ago, what with high manifold pressure forcing integral gates partially open, and limitations with pneumatic control? Am I missing some obvious gotcha? Thanks Sam, will be checking those adaptor hub drawings against my car tomorrow, appreciate you sending them over, cheers. _________________ Best regards,
CMW
Posted: Sat Nov 26, 2011 2:19 pm Post subject: Re: Petrol engine turbos with solenoid control of wastegate?
CMW wrote:
I am sure I read of a new range of petrol engine turbos, maybe from Borg Warner, that use solely electronic control of the internal wastegate flap valves. I am now doubting my sanity as I can't find the reference again. Has anyone any info on this, I have always thought some sort of direct acting servo motor with PID control from the ECU would be superior to pneumatic control indirectly altering the wastegate from the ecu via a boost control valve. Thanks.
Hmmm.... Borg Warner had some stuff on Display at Sema last year, but I thought it was a bypass on the compressor side, EFR series, but maybe there were some prototypes?
Wasn't paying mutch attention, I'm mainly into drag racing where simpler is better. _________________ www.Dynomotive.ca
AEM Factory Trained, Accel EMIC, Haltech Trained, Advanced GM EFI, Diablo CMR Mopar Dealer, SCT TUner - Viper/SRT10, Delta Force Dealer.
Analog DD 450
Mustang MD250 - gone but not forgotten.
Joined: 05 Jun 2006 Posts: 484 Location: Melbourne
Posted: Sat Nov 26, 2011 5:15 pm Post subject: Re: Petrol engine turbos with solenoid control of wastegate?
CMW wrote:
I am sure I read of a new range of petrol engine turbos, maybe from Borg Warner, that use solely electronic control of the internal wastegate flap valves. I am now doubting my sanity as I can't find the reference again. Has anyone any info on this, I have always thought some sort of direct acting servo motor with PID control from the ECU would be superior to pneumatic control indirectly altering the wastegate from the ecu via a boost control valve. Thanks.
Electrical control of things like drive by wire throttle, or the movable vanes in a VNT turbo require very low actuation force.
A wastegate has to hold and control against quite high exhaust back pressure, and the forces required to do that are quite considerable.
To also be very fast acting, will require a fairly high powered motor and electronic driver, which is going to be neither small or low cost.
A diaphragm and a spring is pretty instantaneous, and the actuating forces generated can easily be made high enough with a compact reliable assembly that resists heat well.
If there were any really big advantages in doing it directly with an electric motor and gearbox, it would already be in very widespread use by the money no object racers.
there are lot of electrical actuators for clasic Wastegate flap here in europe, on sprinter, viano, touareg, diesel lexus, avensis.........
google: hella turbo actuator
it works on duty cycle just like a solenoid, even tried one out of a merecedes sprinter turbo....
I think the diesel engines are easier to avoid excessive radiant heat on the actuator though.
I've use a pressurized air resevoir, rather than "boost" as the control pressure source, in order to allow MAP pressures lower than the spring would allow, (in high power cars for the lower gears). AN electric wastegate actuator would have made this simpler, if it can take the heat.
For fuel efficiency there is potential benefit it in highway cruise which can allow less Emap pressure and larger throtttle opening to reduce pumping losses, where otherwise the EMap is higher and the throttle is more closed (wasted "boost" upstream of throttle) to maintain a given cruise speed. Fully opening the w.g at zero boost is just simpler with electric actuation, but have done it pneumatically as well. _________________ www.circuitse7en.net http://stores.ebay.com/Circuit-Se7en
This is one from HELLA on a Garrett VNT. It’s a bit funny to set it up as it got a fail save modes build in but ones you got it working it’s 10x better than an vacuum operated activator.
Did not yet come across one that’s on a normal waste turbo.
Joined: 05 Jun 2006 Posts: 484 Location: Melbourne
Posted: Sun Nov 27, 2011 2:47 pm Post subject:
Yes the Hella unit works fine on a VNT, because the vanes are pivoted in a way that requires only a very low actuating force to hold them in any required position. I works pretty much exactly like drive by wire throttle.
But I doubt if that actuator could hold a wastegate flap closed against 20 psi of turbine inlet pressure, or open against the full force of a spring strong enough to do the job. We all know how strong wastegate springs are, and they are that strong for a reason.
All the electronic turbo boost control systems I have seen, still use boost pressure (or manifold vacuum) applied to a diaphragm actuator, controlled by a small air solenoid, and usually pulse width modulated.
Some diesels even have an engine driven vacuum pump to operate both the turbo control system, plus the power brake booster.
Joined: 26 Aug 2006 Posts: 196 Location: Parma - Italy
Posted: Tue Nov 29, 2011 12:13 am Post subject:
2013 f1 turbo cars will have electronic solenoid controlled wastegates... _________________ TM enduro 250 2s.[55](2s is better than 4s)
Toyota Celica Gt-Four ST205 [588.25Nm@4957rpm]
EFI 101 + Advanced classes
But I doubt if that actuator could hold a wastegate flap closed against 20 psi of turbine inlet pressure, or open against the full force of a spring strong enough to do the job. We all know how strong wastegate springs are, and they are that strong for a reason.
I think it can. The problem is temperature in that aera, not engine torque.
I can't see temperature being a big issue the control solenoid need not be directly by the turbine housing, manifold or turbine exit pipe. It could actuate via a long rod, or even a Morse cable, surely? _________________ Best regards,
CMW
Joined: 11 Sep 2006 Posts: 650 Location: London, England
Posted: Tue Nov 29, 2011 3:38 am Post subject:
I don't think you could direct drive it with a small DC motor as in DBW because these things struggle to control their coil temperatures when they are being held in a fixed position under tension, if you look at all the big payload industrial robots they use heavily geared down induction motors but the induction motors needed for this application would likely be far too large and way too heavy to be practical.
I'd suggest that the way to do it would be to use a small DC motor running the actuator via a worm drive to decouple the tension from the motor then add some elasticity to the actuator arm to enable a specific worm drive absolute position to apply a clamping pressure to the gate.
Joined: 05 Jun 2006 Posts: 484 Location: Melbourne
Posted: Tue Nov 29, 2011 1:45 pm Post subject:
The problem is both the very high force required, and the required speed of movement.
A geared motor simply will not be able to respond fast enough with enough force, unless the motor power is made absolutely huge.
And it will need to be in almost constant motion.
Large motors require a lot of amps, plus a very big driver.
Much better to use either air (or engine oil pressure) to do the physical work, and then use a small low power pulse width modulated solenoid valve to control it. Fast, cheap, light weight.
Which is what we already very commonly see.
Not saying it is totally impossible, just not economical or practical, or worth the trouble.
Joined: 26 Aug 2006 Posts: 196 Location: Parma - Italy
Posted: Tue Nov 29, 2011 3:03 pm Post subject:
What about using an ecu controlled vvt like solenoid that controls pressurized engine oil feed to a 2 port actuator? _________________ TM enduro 250 2s.[55](2s is better than 4s)
Toyota Celica Gt-Four ST205 [588.25Nm@4957rpm]
EFI 101 + Advanced classes
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