Against the backdrop of increased concern regarding the environmental impact of human activity, there are an ever-growing number of studies for the development of individual, collective or merchant road transportation with a view to creating cleaner vehicles. To win a positive response from the market, these vehicles must offer the same level of performance without representing an additional cost for the user. One major improvement strategy involves using high-speed electric motors that are smaller, but with the same amount of power, in order to increase the power-weight ratio of electric power trains, and thereby reduce the weight of vehicles and increase their energy efficiency. However, in order to achieve these gains, new gearboxes, that are able to accommodate the high-speed of the motor with conventional transmission vehicle components, will have to be built. To this end, ECAM Lyon, in collaboration with several companies (VALEO, NTN-SNR, IREIS, HUTCHINSON, TOTAL, REDEX) and other academic laboratories (SUPMECA, INSA-Lyon, CETIM), works on a research project called RedHV+.
The primary focus of this project consists in determining whether or not it is possible to manufacture, at car cost, a high-speed, high efficiency gearbox (30,000 to 40,000 rpm, 20 to 40 kW power). The goal is to be able to exceed the performance of the current chain by incorporating the target weight gains while at the same time guaranteeing the reliability of the system under automobile conditions. In order to achieve an overall gain on the vehicle, the target performance will be equal to or more than the performance of existing gearboxes. Accordingly, it will be necessary to identify and assess technologies that are compatible with the economic constraints of future mobility. Secondly, these technologies will have to be developed to make them industrially relevant on consumer markets thereby making it possible to open up the market of large-series high-speed gearboxes to all industrial partners of the project.
By accepting high input speeds, the gearbox of the REDHV+ project will allow the use of high-speed electric machines in motor vehicles. This goal means that the gearbox will have to be highly efficient: the study of the energy efficiency of high-speed transmission is therefore one of the strong points of the project. The research center of ECAM Lyon (LabECAM) is in charge of developing advanced modeling to quantify the energy behavior of high-speed power transmissions.
This work is financed by national funds through Région Auvergne-Rhône-Alpes and Bpifrance (a public investment bank).