Optimization control actions on electropneumatic valve of actuator of clutch control

Electropneumatic valves are a key element of the electropneumatic clutch control system for vehicles of categories N3 and M3. The speed and accuracy of the clutch control system depend on their parameters. When the operating conditions of the solenoid valve change, its initial parameters also change, even before the loss of serviceability. Goal. The goal of the work is to form dependencies that determine the parameters of the control signal for the clutch control system of vehicles of categories M3 and N3 in the conditions of change of supply voltage, pressure drop on the valve and ambient temperature. Methodology. To achieve this goal, an advanced mathematical model and onedimensional optimization method were used to determine the optimal control effect on the electropneumatic valve of the clutch control system. Results. The block diagram of the control pulse in different modes of operation of the electropneumatic clutch control system is given. Based on the calculated data, the characteristic areas of operation of the electropneumatic valve are determined and the purpose for the optimization process is determined. Based on the defined range of data change and the accuracy of finding the optimal value, a rational optimization method is determined. By modeling the operation of the solenoid valve with parameters according to the chosen optimization method, the response surfaces were constructed relative to the control pulse depending on such parameters as supply voltage of the vehicle onboard network, ambient temperature and pressure drop on the solenoid valve. Originality. The error in the reproduction of the theoretical response surfaces based on the parameters of the clutch and the electronic control unit is also determined. Theoretical aspects for providing the required inductance of the solenoid valve coil are shown. Practical value. A method for determining the pressure drop on an electropneumatic valve is proposed. The method takes into account the change in pressure during operation of the clutch control system due to wear of the friction plate. The error in ensuring the duration of the control pulse due to the presence of hysteresis in the operation of the clutch and the executive control device is estimated.

A Dynamic Model of an Electropneumatic Valve Actuator for Internal Combustion Engines

This paper presents a detailed model of a novel electropneumatic valve actuator for both engine intake and exhaust valves. The valve actuator’s main function is to provide variable valve timing and variable lift capabilities in an internal combustion engine. The pneumatic actuation is used to open the valve and the hydraulic latch mechanism is used to hold the valve open and to reduce valve seating velocity. This combination of pneumatic and hydraulic mechanisms allows the system to operate under low pressure with an energy saving mode. It extracts the full pneumatic energy to open the valve and use the hydraulic latch that consumes almost no energy to hold the valve open. A system dynamics analysis is provided and followed by mathematical modeling. This dynamic model is based on Newton’s law, mass conservation, and thermodynamic principles. The air compressibility and liquid compressibility in the hydraulic latch are modeled, and the discontinuous nonlinearity of the compressible flow due to choking is carefully considered. Provision is made for the nonlinear motion of the mechanical components due to the physical constraints. Validation experiments were performed on a Ford 4.6 l four-valve V8 engine head with different air supply pressures and different solenoid pulse inputs. The simulation responses agreed with the experimental results at different engine speeds and supply air pressures.