Actuation System for Variable Compressor

The main focus of this Master Thesis is the development and evaluation of an actuation system that controls a variable compressor for the automotive industry. This variation allows the compressor to produce different boost pressures on demand. Before the development process could start a theoretical analysis of the different forces acting on the system were conducted. These analyses consisted of a dynamic mechanical part, a gyroscopic part and one pressure part. These results were then used together with the defined geometry as input to the development project. Our Master Thesis was executed for Manomeka AB, a newly founded engineering company developing a mechanically driven variable compressor for the automotive industry. The company has developed the compressor over the last couple of years in collaboration with the department of design sciences at the Faculty of Engineering, LTH. The development of the actuation system is divided into four different subproblems: 1. Design and analysis of a support element that controls the movement and positioning of the actuation system. This part mainly consists of mechanical design and dimensioning, using finite element analysis. The goal here was to design a very stiff structure that could control the actuation in a precise way. 2. Positioning, type selection and dimensioning of bearings. Using recommendations and bearings from SKF. 3. The selection of a motor that could control the positioning of the support element. Main focus was to find a cheap, small and strong enough motor using the allowed power supply of 12 V. 4. Design of a force reducing system that counters the pressure forces acting on the system. This system allows for the use of a smaller motor. During the work with the different subproblems the interactions between them were closely monitored and defined, this made it easier to assemble them at a later stage. The lack of space inside and around the compressor made the choice of shapes and dimensions of the different parts very important. A final concept for the actuation system is presented in the report together with comments and suggestions for possible variations. The chosen concept consists of an outer support element that positions the actuation system. The support element has standard bearings mounted to allow for rotation relative other components. The support element is actuated using a single linear actuator placed on top of the compressor. To reduce the forces that the motor needs to control a spring system is utilized.