Functional testing for automotive powertrains

A Geo Kingsbury Machine Tools product story

Edited by the Engineeringtalk editorial team Oct 21, 2003

A Gosport company, Geo Kingsbury, has emerged as a world leader in the manufacture of powertrain test equipment, winning many of the orders placed by automotive OEMs over the past eight years.

A Gosport company, Geo Kingsbury, has emerged as a world leader in the manufacture of powertrain test equipment, winning many of the orders placed by automotive OEMs over the past eight years.

A recent contract, valued at US $3.5 million, was awarded by Daimler Chrysler Power Systems for three truck transmission test stands.

Two of them have been integrated into production lines at Sao Paulo for 100% per cent functional testing of five different types of manual gearbox for medium-size trucks.

The third stand is for audit purposes, submitting sample gearboxes to a rigorous sequence of tests.

A second order, valued at US $2.5 million, has since been received from Daimler Chrysler for two more end-of-line test stands.

Due for delivery by early 2004, these latest test stands will accommodate the above gearboxes and additional types manufactured at Sao Paulo, allowing considerable flexibility of quality control within the factory.

The audit stand also accommodates the additional gearbox models.

The production stands take gearboxes as they come off the lines at Sao Paulo and subject to them to a series of quality checks in a floor-to-floor time of approximately 5min - 1min for loading, 3min for testing and 1min for unloading.

The boxes are prefilled with oil before they reach the stand's input conveyor, where an operator scans a barcode to identify the model.

The corresponding test programme is uploaded automatically to the PC controller ready for the next test.

All the operator has to do is fit relevant shaft end adaptors to the gearbox, as connection to the input and output drive motors of the stand is completed automatically.

This has the effect of connecting the gearbox both mechanically and electrically.

A sequence of tests is performed following on-screen prompts telling the operator when to sequentially engage all six gears.

A 75kW input AC electric motor and a 185 kW output motor, both variable speed, automatically cycle the gearbox through a series of pre-programmed tests at various speeds from zero to 3600rev/min and torques to a maximum of 1800Nm, concentrating on known problem areas of actual drive conditions.

The operator performs a subjective test on each gearbox, listening for any undue noise and vibration.

The gear ratios are measured to check for correct assembly and it is also verified that the speedometer, neutral and reverse switches are operating.

The audit stand is similar, except that there is no conveyor load/unload and it is installed in an acoustic enclosure.

Another difference is that whereas noise tests are subjective on the production stands at Daimler Chrysler, the audit rig is equipped with full NVH (noise, vibration, harshness) equipment for carrying out objective, measurable evaluation of how smoothly or otherwise the gearbox runs.

One-offs or batches of gearboxes are subjected to endurance tests, typically over several hours, looking for potential points of failure particularly under cyclic loading and elevated oil temperatures.

So that an operator is not tied up doing this job, the stand is automated with the addition of a robot for shifting the gears under program control.

The principal purpose of this stand is to assist in the development of new gearboxes and to investigate warranty claims.

There is an interim role that it could perform, namely that of keeping an eye on process capability and helping to spot parameters drifting out of tolerance, but at present it is not intended that the equipment will be used for this purpose.

System control software writing and programming, whether it be for PLC- or PC-based controls, are carried out in-house at Gosport, minimising reliance on third parties and facilitating the setting up of PC-to-PC Internet links between the customer site and Geo Kingsbury for remote troubleshooting, if required.

Geo Kingsbury is so sure of the quality and functionality of its automotive test equipment that it offers an industry-leading warranty and uptime guarantee.

With the exception of wear items, the company provides free service and parts for its test stands during the first two years and guarantees 94% uptime.