We are in the early planning stage of designing an hydraulic engine dynamometer for internal use. We are looking at using a hydraulic pump as the load for the engine. We are planning to apply load to the hydraulic pump with a servo valve partially obstructing the flow of the hydraulic fluid. To measure power, we can either measure the pressure of the fluid and multiply with the RPM and a correction factor or measure the torque with a strain gauge and multiply with the rpm.

We need some advice on where to find a reasonably priced hydraulic pump that can transmit approx 600 kw / 850 Nm thru its shaft reliably.

The RPM of the engine is max 8500 RPM.
We might have to gear down this to a RPM the hydraulic pump can handle.

I was thinking about hydraulic pumps for dumper trucks and digging equipment like CAT or Komatsu. This kind of equipment is mass produced and I would think a lot of spare parts suppliers exist.

Also, where can we find servovalves that can handle this pressure with a fast response ?

We would like to cool the fluid via a water to oil heat exchanger. Any hints on suppliers ?

This has actually been done before in an chassis dyno application for cars.

The unit in left front of the picture looks like the hydraulic pump they use (does anybody on this forum recognize the brand of this pump by any chance?).
 
Looks like the unit on the right with the piping is the servovalve unit that applies load to the hydraulic pump. The black unit on top is probably the servomotor for controlling the servovalve. A pc is attached that runs some real time control software.

The brake assembly is attached directly to the driveshaft of the car.
I think there is a gearbox attached between the driveshaft and the hydraulic pump. Anyone that know a manufacturer compact of gearboxes that can handle this much power and torque (600kW / 850Nm) ?

Here is a link to a  pic of the servovalve they use
Anybody recognize any of the components or is it custom?

We are not going to attach our dynamometer to the driveshafts, but directly to the engine crankshaft thru an axle. Therefore we need it to be able to handle at least double the power of this unit since the car differential distrubutes power to two driveshafts and two units.In-line pumps

2011-05-30

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