A Kalman Filter for Sensorless Control of a Piezo Actuator for Camless Internal Combustion Engines Kemo Hodzic, Paolo Mercorelli and Nils Werner Abstract— This paper deals with an actuator composed by a piezo and a servo piston and a Kalman Filter structure for camless engine motor applications. The considered system is assumed to be linear. The electrical actuator is realized with a piezostack which operates between 0 - 1000 V . The piezostack is connected through an reduction ratio with the servo piston, this link causes the mechanical movement of the servo piston. This paper will show measured velocity and position of the piston - shown by real simulation data- and simultaneously the estimated data which were calculated and simulated with MATLAB/Simulink, by the recursive estimation algorithm by R. E. Kalman. I. I NTRODUCTION AND MOTIVATION Combustion engines are widely used since more over 100 years. Due to the finite nature of resources of fossile fuels the now guided discussions for replacement solutions of these energy sources and the development of radical alternatives for vehicle propulsion systems are essential. However com- bustion engines will determine the concepts of our mobility, which are very similar to today’s engines. In the future thus it is useful to deal with the internal combustion engines.[3] The primary task of the valve train is to control the charge exchange for the combustion process. This requires energy, which is supplied by the crankshaft. An efficent valve train can thus greatly improve the efficency of internal combustion engine [4]. In the last five years, variable engine valve control in camless systems has attracted a lot of attention because of its ability to reduce pumping loses (work required to draw air into the cylinder under part-load operation) and to increase torque performance over wider rage than conventional spark-ignition engines. Variable valve timing also allows control of internal exhaust gas recirculation, thus improving fuel economy and reducing NOx emissions. To realize this variable valve timing this paper presents to use the piezostack composed with the reduction ratio and servo piston (Figure 3). With the development of the mathematical structure of Kalman filter, an approach is developed that makes it possible to estimate states of the linear system. The basic model data for simulation from [7] are required for the development for the Kalman filter in Camless Combustion Engine. Figure 1 shows a three dimensional model of the combustion engine from a motorcycle. It is designed with Kemo Hodzic and Paolo Mercorelli are with the Leuphana University of Lueneburg, Institute of Product and Process Innovation (PPI), Voll- gershall 1, D-21339 Lueneburg, Germany. Tel.: +49-(0)4131-677-5571, Fax: +49-(0)4131-677-5300. kemo.hodzic@stud.leuphana.de mercorelli@uni.leuphana.de. Nils Werner is with the Fac- ulty of Automotive Engineering, Ostfalia University of Applied Sciences, Kleiststr. 14-16, D-38440 Wolfsburg, Germany. Tel. +49-(0)5361-831615 Fax. +49-(0)5361-831602. n.werner@ostfalia.de four piezo actuators, each of them is able to control two valves simultanously from the two cylinders. Presently the measurement from position and velocity are realized with an magneto resistiv sensor, see [9]. This paper will present an approach which is able to predict the states of velocity and position of the servo piston in Figure 3 so the control of the valves will be more accurate. The Kalman filter (KF) is an optimal estimator - ie infers paramters of interest from indirect, inaccurate and uncertain observation. It is recursive so that the new measurement can be processed as they arrive. If all noise is Gaussian, the KF minimises the mean square of the estimated parameters. In this case the filter is using the data from the MATLAB/Simulink model (voltage V z and position x SP ) which will be explained in the second section. Fig. 1. 3D model of the build in piezo piston, servo piston and valve in a combustion engine This paper is structured in the following way. Section II describes the structure of the proposed system an gives the general specifications to be satisfied and section III is dedicated to Kalman filter. Section IV shows the simulation data of the system. Finally simulation and conclusion close the paper. II. DESCRIPTION OF THE MATHEMATICAL MODEL AND THE CONSIDERED MECHANICAL SYSTEM To realize this variable valve timing this paper presents the use the piezostack composed with the reduction ratio and servo piston. (Figure 3). The piezo-stack (Figure 2) is a multilayer ceramic capacitor whose dimensions change during electrical charges. For driving purposes, the axial strain is utilized. The mechanical forces (displacement, force) 978-1-4799-4749-2/14/$31.00 ©2014 IEEE 2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion 1225