GreenMot Develops Custom Systems for Engine Testing

When GreenMot started its activities in October 2010, it chose neither a “comfortable” market nor a simple path. The market for the testing of engines has a large number of actors with well-established leaders. At the time, this market had experienced several crises, particularly in the automotive sector. And GreenMot didn’t take the easy way in order to break into this market; it decided to start from scratch, without taking over an existing company, and hence having to develop its complete client portfolio. But its founder and president, Stéphane Londos, has vast experience and he chose an approach that would quickly enable the company to hold its own: he focused on precision tests, and if the necessary sensor did not exist, he developed a custom sensor in order to adapt it to the structure to be tested, and not vice versa.

That is how GreenMot uses its in-situ sensor directly integrated into the engine to measure the torque of the tested engine. This sensor has been specifically developed in order to be adapted to the mechanical and environmental stress of the engine. HBM is at the heart of this strategy. As a technological partner from the very beginning, HBM supplies the complete instrumentation chain, for the majority of GreenMot’s applications. Both companies benefit from this privileged partnership: GreenMot is able to distinguish itself from its competitors while HBM consolidates its know-how in engine applications and uses its experience and knowledge to develop new products. 

The company’s strategy has evolved accordingly over the years. That is why there are now two distinct fields of activity: testing based on the clients’ specifications on the one hand, and the construction of testing equipment on the other.GreenMot offers turnkey tests for its testing operations. This approach starts with the specification of the sensors, followed by the planning of the test campaign and post-treatment according to the client’s needs. Test duration can range from one day to several months, starting from the validation of the conditioning, adjustment of the pollutant system, through the complete vehicle benchmark analysis. Tests are generally performed at GreenMot facilities, but in some cases, they can be provided on the client’s site.

The second field of activity involves the development and supply of testing machines and allows GreenMot to use its experience gained in the first field to offer testing machines of a higher quality. These machines are specifically developed based on customer specifications, the R&D department works directly with them. The common denominator of these two activities remains the specific measurement, but the convergence goes much further, says Sébastien Ferragne: “There are very strong synergies between these two activities. Testing operations help us design new testing equipment, just as the development of testing machines helps us to carry out the tests. These synergies give us high dynamics and enable us to create an added value compared with our major competitors who do not have this double activity of testing and testing machines production.”

To define these sensors, GreenMot draws on its own competencies in mechanical engineering used for designing its test benches. The engineers use the CAD models of the vehicles to be tested (these models are either provided by the manufacturer or are created by digitization of parts by a partner). The actual sensors consist of a sensor body on which HBM strain gauges and the transmitter for the measured values are mounted. The development methodology for these torque transducers follows the classic V model with all the project definition steps on the downward line of the V and different manufacturing and validation steps on the upward line of the V. Process development can take between 18 and 20 weeks. Here HBM provides its know-how in the field of sensors, in particular regarding the positioning of the strain gauges, and ensures their adhesion to the test body and the use of the associated process to guarantee the quality of the results. Classic strain gauges are used, but within the context of these co-developments with GreenMot, specific geometries or temperature compensations had to be evolved. Precisions obtained are better than 0.1% in the laboratory and 0.2% in real environments. The measurement frequency is 1 kHz.