Analysis of the parameters of the double clutch drive with reduced control energy consumption

The global trend of improving vehicle and traction transmissions is associated with the use of robotic preselector gearboxes, an important component of which is the friction clutch. The review of existing designs and analysis of clutch development concepts allows determining the directions of their improvement, in particular, the improvement of dry double clutches, which is the subject of research in this paper. A significant disadvantage of existing dual-clutch designs is the use of additional special (mostly hydraulic or combined) systems for on-off friction pairs, so the structural cost and energy costs for control are increased, and the design, maintenance, and repair are complicated. The proposed design of the drive to control the original dry dual-clutch involves a lever mechanism with the use of rotary stops, which are made in the form of mobile carriages with rollers, this provides switching clutches in a short time and actually without interruption of power flow, so the acceleration dynamics of vehicles will be improved, the clutch design will be simplified and energy consumption for its control during the start and gear shifting will be reduced. The mathematical model of the proposed clutch drive on the basis of which the control mechanism operation is simulated and influence of its design parameters on operational indicators of the clutch drive, in particular, on kinematic characteristics of the drive, ranges of kinematic and power gear ratios, the power interaction of the mechanism links, the power of the actuator when each clutch is turning on. It is established that the switching of clutches requires less energy, the movement of the mechanism elements is different, and the compression force of the friction pairs when starting the first and second clutches is different. The simulation results confirm that the proposed original lever design of the clutch control mechanism is effective. The obtained results allow us to reasonably determine the parameters of a clutch, but the choice of optimal-rational parameters of its control mechanism requires further research, for which appropriate methods, search algorithms, and their software implementation have been developed.

Analysis of Improving Automatic Transmission Upshift Performance by Using Off-Going Clutch During Inertia Phase

The paper presents a detailed numerical and algebraic analysis of potential for improving the step ratio automatic transmission (AT) upshift performance by means of modulating the off-going clutch during the inertia phase. The numerical analysis is based on Pareto optimal frontiers obtained by using the previously developed methods for AT shift control trajectory optimization and piecewise-linear control profile parameter optimization, where the control objectives include minimization of shift time, vehicle RMS jerk, and clutch dissipated energy. The analysis concerns the following control scenarios related to inertia phase: 1) oncoming clutch control only, 2) combined action of oncoming and off-going clutch; 3) oncoming clutch control extended with engine torque reduction control, and 4) combining all three control actions. The numerical results relate to an advanced 10-speed AT and various single-step and double-step upshifts, with emphasis on 1-3 shift. The numerical analysis results are proven algebraically based on a simplified AT model represented in bond graph form. The presented analysis shows that the off-going clutch can reduce either shift time or RMS jerk index by introducing power recirculation via the two clutches, which is in turn paid for by certain increase of AT energy loss.

Motion Characteristics of a Clutch Actuator for Heavy-Duty Vehicles with Automated Mechanical Transmission

Clutch control has a great effect on the starting quality and shifting quality of heavy-duty vehicles with automated mechanical transmission (AMT). The motion characteristics of a clutch actuator for heavy-duty vehicles with AMT are studied in this paper to investigate the clutch control strategy further. The modeling principle of the automatic clutch system is analyzed, and a simulation analysis is given to prove its validity and rationality. Normalized velocity and velocity modulation percentage are proposed as evaluation parameters for the clutch actuator driven by pulse width modulation (PWM) signals. Based on an AMT test bench, the actuator motion characteristics are analyzed. Experimental results show that the range of normalized velocity and velocity modulation percentage are obtained for the clutch engagement and disengagement processes. By analyzing the experimental data, the engaging velocity and disengaging velocity of the actuator are estimated using the solenoid valves in combination. The research results provide a fundamental basis for precise controlling of the clutch and improving the smoothness of heave-duty vehicles.

THE CONCEPT OF THE CLUTCH CONTROL LAW OF A CAR

Problem. The combination of comfortable automatic control of the car's transmission and at the same time preservation of high indicators of energy efficiency and cost of a design is possible by use of automatic mechanical transmission. The automatic clutch control system plays a significant role in providing comfort in such transmissions. The laws of controlling it are not perfect today. Goal. The aim of the work is to create a clear concept of the law of clutch control, which is easy to implement in a microcontroller and is well adapted to adapt to different driving conditions. Methodology. Graphically, the concept of the perspective law of clutch control is formed by two Bezier curves. One of the curves acts as a guide, and the other forms the surface of the law. Results. On the basis of the Bézier curves of the third degree the concept of the law is formed and the connection of the reference points of the Bézier curves with the physical parameters of the working process of vehicle movement is substantiated. Originality. The formation of the Bézier curve, which is decisive for the concept of the law, is formed on the basis of a typical working process of synchronization of the angular velocity of the clutch discs during the movement of the vehicle. In contrast to the laws of clutch control considered in the scientific literature, the proposed concept provides for clutch control outside the site of the synchronization process and ensures the avoidance of jerks during further acceleration. Practical value. The proposed algorithm provides full engagement of the clutch only after full synchronization of the clutch discs. The formation of a special form of the law in the form of a curve tangent to the abscissa axis reduces the jerks when closing the clutch discs.

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.