Multi-Cylinder Valve Control - FPGA-controlled Pneumatic Variable Valve Actuation

Abstract: The society of today relies heavily on transportation. Goods and people are transported across the globe at an unprecedented scale and volume and the internal combustion engine is an integral part of the world's transportation systems. Combustion engines emit greenhouse gases that contribute to global warming, one of the most serious global threats today. One of several ways to increase efficiency and reduce exhaust emissions of ICEs is the use of variable valve actuation. The purpose of this thesis is to implement a control system for a variable valve actuation system from Cargine in a Volvo D12 cylinder head, a 12-liter heavyduty engine with six cylinders and 24 valves. The cylinder head is to be used in a laboratory engine at Lund University. The task consisted of two parts. Investigation of relationship between control pulse sent to the actuators, actuator pressure and valve displacement. The second part is to create a Field Programmable Gate Array (FPGA) based feedback control system in Labview to obtain desired valve open time, valve close time and lift. A second order model of the exhaust valve was identified. An FPGA based feedback control was implemented for all 24 valves in Labview. Satisfactory control of valve open timing and valve close timing and lift for a fixed engine condition was obtained. A Kalman filter was implemented on one valve, leading to a small increase in performance. Implementing a Kalman filtering in the controller on all valves would either require, optimization of the Kalman filter implementation, some kind of signal condition, or additional computational resources. The system defined and implemented in this thesis can serve as the basis of further experiments for modeling the effect of cylinder pressure and actuator pressure on valve open timing, valve close timing and lift.