Tailor-made cooling for mobile machines

10 June, 2016

The customer decided to work with Hydac as their system partner and forwarded the design details of the machine in the form of 3D data. Based on the installation dimensions taken from the 3D model, a schematic diagram was prepared. The suggestion to arrange the individual cooling circuits in the 3-dimensional space was approved (see diagram in Fig. 2). This configuration had a significant advantage over the original cooler design: cool ambient air was now available to all the cooling circuits. This therefore made it possible to increase the capacity of the cooling system considerably.

Hydraulic fan drive provides better characteristics

The fan used was driven directly by the engine and was operating permanently at maximum speed, with the associated noise pollution. The requirement for both higher system efficiency and noise reduction was achieved by introducing variable fan speed control via hydraulic fan motor drive.

This resulted in the fan rotating at a speed to best suit the conditions of any particular situation, enabling much lower speeds to be reached during periods of reduced heat load/ambient conditions. The result enabled a reduction in both fuel consumption and noise pollution.

The fan cowling was also used as the frame for the cooling system, so the individual cooler circuits were all integrated within this. The gear oil cooler was split into two sections mounted on each side on the pack and then connected in series. These both utilised the remaining areas whilst also better suiting the high duty requirement of the oil circuit.

In order to satisfy another requirement made by the gearbox manufacturer for a maximum pressure differential in the circuit of 3 bar, the patented Hydac combined thermal and pressure bypass valve (IBT-2/50) was integrated into the oil radiator.

Overall concept of the cooling system

The cooling package followed the geometry of the engine bonnet, so in order to ensure simple installation the connections from the coolant cooler and hydraulic oil cooler were fitted through the fan cowl and were sealed using rubber grommets.

The vehicle manufacturer has got a cooling system which meet all the requirements set out in the specifications and reduced the total noise emissions of the machine by a formidable 13 dB(A). This example shows that using relevant knowledge from the right partner, there is still potential for optimisation of modern cooling concepts.

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