Hamersham are experienced in hydraulic fan control software for off-highway mobile working vehicles.

The ability to shut off the hydraulic cooling fan is essential when working in extreme cold. This means engine starts can be performed without any forced air cooling resulting in a faster heat up time to optimum working temperature. Any hydraulic fan must be controlled by a hydraulic valve that is capable of completely shutting off the fan hydraulic motor.

All fan motors must be controlled by a valve that has excellent proportional metering characteristics. This means very fine and repeatable fan speed control can be done at all times.
-Fan speed control is essential to ensure that the fan does not over speed and damage blades.
-Good fan speed control is also essential for controlling fan noise levels.
-Proportional control of the fan is also important for controlling signal ramps. Ramp up and ramp down of the fan control signal is very important for smooth control of speed changes.
-Delivering the correct fan speed for the cooling required helps with fuel efficiency.

Hydraulic fans on mobile machines can sometimes be required to perform cooling from multiple demands in a system. For example, control systems that command combination coolers can often be required to simultaneously cope with a cooling demand for the engine coolant, the hydraulic temperature, intake air temperature and others. Hamersham has experience in combining cooling curves in software. The cooling curves need to be vectorised and handled intelligently so that competing cooling demands do not conflict and cause continuous fan speed changes.

Different fan cooling modes are also often required:
-Cleaning: Fans are often required to reverse or run at high speed for a short period of time in order to clean the blades and radiator.
-Fans may need to change direction to suck or blow air across the radiator according to varying machine operating conditions.

Hydraulic fans being powered from load sensing systems may need software detection of load sense instability. If the load sense pump is detected to be going unstable, then cooling fan software can modify signals to bring back stability.

Finally, what is the best hydraulic control strategy for a hydraulically driven fan?
-Pressure Control: This works well when a proportional pressure control valve is used to control the speed. A pressure control valve varies the torque applied to the fan motor and therefore makes the fan increase/decrease speed.
-Flow Control: This works well when the directional flow control spool position is controlled accurately. Special spools are sometimes required.
-Hamersham has had software control experience and success with both methodologies.

Advanced diagnostics can also be performed with intelligent fan software. For example:
-Excessive pressure ripple in the fan circuit can indicate a broken or damaged blade.
-If cooling at full speed is not being effective then broken radiators may be detected.
-Abnormal temperature heat up curves may indicate a faulty component and prompt service checks.

For more information regarding Middleware, please contact Nick Pridham at Hamersham at nick@hamersham.com or call 07717 790404