Nigelw Posted January 11, 2014 Share Posted January 11, 2014 Had a little riddle going around in my head tonight whilst tipping away in the barn, and I wonder how much energy is being wasted through running a PAS pump full time? Not that I want to change that side of it but. Is there much power in the PAS system without turning the hard from lock to lock? Maybe enough to run a hydraulic fan??? ideas please Quote Link to comment Share on other sites More sharing options...
jbs Posted January 11, 2014 Share Posted January 11, 2014 Nigel, The milemarker basic kit comes with adaptors for use with the vehicles original PAS hoses, So there must be a fair amount of power being on offer? John Quote Link to comment Share on other sites More sharing options...
Nigelw Posted January 11, 2014 Author Share Posted January 11, 2014 Hi John, I have this idea in my head that I want to fit electric cooling fans for the rad but I also want to be sure that the intercooler has enough air flow through it, the problem I have is that with no viscous fan there will be no air movement through the intercooler, or at least very little when in slow moving situations off road. My idea was/is to try and make use of wasted hydraulic power that is not being used by the steering to run a hydraulic fan to ensure sufficient air movement through the intercooler, figured it would be better that it did something rather than just burning my diesel and circulating round the system under pressure? Quote Link to comment Share on other sites More sharing options...
Tanuki Posted January 11, 2014 Share Posted January 11, 2014 The energy is not being wasted - when the pump has achieved the necessary pressure in its output-port a relief-valve opens and then the amount of energy needed to turn the pump in the absence of anything taking fluid from the pump the energy needed is just what's needed to maintain the set-point pressure - really rather low. [in the same way, your alternator may be capable of producing 100amps @12V which is 1.2 Kilowatts - power needed to be taken from the engine. But it has a regulator so once the battery is charged the regulator reduces the output - and hence the amount of energy needed at the pulley - accordingly]. Hydraulic-motor-driven cooling-fans and coolant-pumpsare standard fitment on Diesel trains and lots of other industrial heavy engines: they have the advantage of infinitely-variable speed/torque control. These engines don't usually have coolant-thermostats like we're used to - they regulate the fan- and water-pump speeds to manage the engine temperature. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted January 11, 2014 Share Posted January 11, 2014 Been there and thought that. Or at least, the hydraulic fan part I can raise 50psi on my dry sump pump easily with a speeder bar and socket with little effort. (belt removed). The oil free-wheeling in the power steering circuit will use even less energy, so no pressure there. Going backward and forward on this over time, the best way is to fit a second pump to run the fan. One disadvantage is that the electric fan runs near full speed at tick-over, whereas the hydraulic fan will vary quite a bit in speed (unsure how much). One major advantage is that the alternator has less to do. We lost fuel pressure when the alternator belt got wet and slipped, dropping the voltage due to all the fans we run. One primary hydraulic fan for the rear rad would be very welcome ! Quote Link to comment Share on other sites More sharing options...
Tanuki Posted January 11, 2014 Share Posted January 11, 2014 Going backward and forward on this over time, the best way is to fit a second pump to run the fan. One disadvantage is that the electric fan runs near full speed at tick-over, whereas the hydraulic fan will vary quite a bit in speed (unsure how much). A hydraulic fan can run at whatever speed it needs to - the hydraulic motor is a variable-nozzle thing [like a variable-nozzle turbo] so the speed it turns at is not directly related to the pressure of the hydraulics. Think about when power-steering is working the hardest - when manoeuvring at low, parking- or trailer-reversing type speeds. As the vehicle road-speed goes up the need for power-steering is less. The PAS pump is therefore designed to produce lots of thrust at low engine-RPM, so coupled with a variable-speed fan motor would be ideal to power cooling when the engine's idling. Fan RPM is dictated by the fan-controller - and a PAS pump will happily give a Kilowatt or so of energy. For an equivalent electric fan you'd need 100-amp-continuous rated wiring to it. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 11, 2014 Share Posted January 11, 2014 If you were looking for a cheap hydraulic fan, then find a Lexus Soarer, they have one as standard Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted January 11, 2014 Share Posted January 11, 2014 There's no reason why you can't use PWM to drive a standard DC cooling fan electrically. Quote Link to comment Share on other sites More sharing options...
Daan Posted January 11, 2014 Share Posted January 11, 2014 Hi John, I have this idea in my head that I want to fit electric cooling fans for the rad but I also want to be sure that the intercooler has enough air flow through it, the problem I have is that with no viscous fan there will be no air movement through the intercooler, or at least very little when in slow moving situations off road. My idea was/is to try and make use of wasted hydraulic power that is not being used by the steering to run a hydraulic fan to ensure sufficient air movement through the intercooler, figured it would be better that it did something rather than just burning my diesel and circulating round the system under pressure? Hi, my opinion is the power lost to flow the fluid will be minute. If you were to fit a hydraulic fan, you would up the pressure, and use more power. It would be no different from driving the viscous, except there are 2 power conversions in between, which will give you more losses. I have considered a hydraulic fan for a radiator in the rear, so you dont rely on electric fans only. As you say, removing the viscous will stop all airflow through the intercooler, not good. If you think you are overcooling, I'd say partly blank off the radiator, and the intercooler will get more air flow through it as well. Quote Link to comment Share on other sites More sharing options...
Nigelw Posted January 11, 2014 Author Share Posted January 11, 2014 Hi Daan, this thinking is actually inspired by you and your build thread of your series, I paid particular attention to your posts regarding the intercooler and how the viscous is necessary for it to maintain efficiency with a continuous air stream being drawn through it even when stationary to drop the heat levels from the unit as it needs the flow even when not on boost and cooling the charge as the heat build up still needs to dissipate to atmo. TBH the idea of over cooling hadn't yet crossed my mind it was more about reducing power drain from the fan. I was looking for a means of scavenging the potentially(in my unknowing mind only) wasted energy from the PAS system to give me a means of reducing drag and power loss on the engine from running a viscous but by using the PAS system to give a hydraulic fan system that would serve mainly the intercooler but also have the flexibility to be shifted over if the electric fan were to pack up. Think maybe I have hit a dead end with this idea Quote Link to comment Share on other sites More sharing options...
muddychris300tdi Posted January 11, 2014 Share Posted January 11, 2014 Could you not fit a small energy efficient electric fan to the intercooler that would only come on below a set rpm. So when stationary or crawling in traffic. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted January 12, 2014 Share Posted January 12, 2014 Viscous fan should be heat operated shouldn't it? The one on my Ford Pinto Transit van is supposed to drive more when the spindle gets hot? (According to our Terry, font of knowledge car and van). To be honest, what I could do with is a hydraulic drive rear fan and a hydraulic drive alternator. The belt only needs to do the water pump then, and the alternator could be by the battery and it wouldn't get drowned every time the crank dipped into water. (On the DMU trains there was a set up than ran two alternators, so there is precedence on this). I suppose I could put a second steering pump where alternator was? Then give the alternator a screw on dummy shaft, key-way it, chuck on a 15" industrial fan and a group 1 drive coupling + motor. I wouldn't go mad on the motor, I'd chance a pump with a run-on valve to protect the seals. If the oil came from the steering res the oil-cooler could go at the back as well, removing heat from the engine bay. Nearly looks like a plan Quote Link to comment Share on other sites More sharing options...
Nigelw Posted January 12, 2014 Author Share Posted January 12, 2014 Viscous fan should be heat operated shouldn't it? The one on my Ford Pinto Transit van is supposed to drive more when the spindle gets hot? (According to our Terry, font of knowledge car and van). To be honest, what I could do with is a hydraulic drive rear fan and a hydraulic drive alternator. The belt only needs to do the water pump then, and the alternator could be by the battery and it wouldn't get drowned every time the crank dipped into water. (On the DMU trains there was a set up than ran two alternators, so there is precedence on this). I suppose I could put a second steering pump where alternator was? Then give the alternator a screw on dummy shaft, key-way it, chuck on a 15" industrial fan and a group 1 drive coupling + motor. I wouldn't go mad on the motor, I'd chance a pump with a run-on valve to protect the seals. If the oil came from the steering res the oil-cooler could go at the back as well, removing heat from the engine bay. Nearly looks like a plan Great, now post that back in simple English so this old bog trotter can understand Only kidding, glad something is coming of this then Quote Link to comment Share on other sites More sharing options...
Team Idris Posted January 12, 2014 Share Posted January 12, 2014 Alternator, ind fan, motor set - It would be a big old assembly Quote Link to comment Share on other sites More sharing options...
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