Renault Reduces Transmission Manufacturing Time with the Help of Simulation

The French carmaker Renault has been utilizing a sophisticated Simcenter Amesim simulation software provided by Siemens PLM to improve its transmission development process and prevent final-stage challenges with meeting production deadlines.

Today, numerous carmakers give preference to automated manual transmission (AMT) for their new cars. This solution combines the fuel economy, operating characteristics and control advantages of manuals with the handiness of automatics in the city traffic with many stops.

Thanks to these advantages and high competitiveness in the auto repair industry, car manufacturers invest significant financial resources in development of commercially viable and ideally shifting automated gearboxes. But, manufacturing of these sophisticated transmission units requires much time and effort because their operation capacities directly depend on the performance of 3 diverse subunits all functioning together in ideal combination: an electro-mechanical drive that changes speeds, sensors that keep car condition in check, and software installed in the transmission control unit (TCU).

Commonly, it takes up to 12 months to specify the overall performance specifications, design the actuator mechanisms, create a software solution for TCU, and officially approve the complete unit. The most problematic aspect of the whole process is software development and its calibration. This development stage usually requires a full-scale physical testing that can be conducted only when hardware prototypes are ready.

Easy-R AMT installed in Renault models

By that time, mechanical and electronics structures are almost ready and cannot be altered significantly to enhance powertrain characteristics. Frequently, it turns out that engineers do not have enough time for TCU control optimization. To start production in time, carmakers frequently have to focus on complying with application requirements rather than on finding a balance between performance characteristics of all transmission components.

Therefore, Renault came up with the idea how to improve the automated gearbox production process with a simulation-based method using Simcenter Amesim software. Specialists of the French carmaker assure that this solution will help to foresee the performance and functionality of car components by means of simulation. According to Renault representatives, this simulation method based on

Simcenter Amesim, allows engineers to see at early stages of development how different components of the sophisticated AMT unit will operate together at early stages of the development process. This solution will help to optimize the entire transmission design in advance and successfully meet gearbox design requirements.

In fact, the company has recently applied this method to design a new actuator for one of its existing AMTs, change the current control unit algorithm, and estimate operating characteristics of the gearbox. At early stages, a simple model was designed to specify general powertrain load limitations and size the main mechanical units. Next, the required information was added from the technical specifications to draft overall performance curves, identify main control commands and specify the overall response of the mechatronics unit. In these preliminary engineering phases, Renault specialists monitored the operation of different mechatronics configurations until the desired characteristics were obtained. These results were used to design control algorithms that formed a basis for development of highly-accurate software for the TCU.

Simcenter Amesim software in action

The software was used to simulate the operation of engine and gearbox as substitutes while the actual car components were still underway. After that, the control unit software performance was ratified and calibrated to test the system model on a real-time basis. Thanks to the simulation method, Renault specialists accurately adjusted the TCU software to achieve optimal powertrain performance characteristics. As a result, Renault will be able to manufacture more cars equipped with more automated gearboxes twice as fast.