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A. Prokop et al.
2.3 Multibody Simulation
First, the virtual prototype of the heavy-duty gearbox was created. The parametrical
open code written in ADAMS was modified to use for complex structure and the script
was extended for shift application. The virtual prototype includes flexible bodies of
key component, stiffness and damping representation of bearings [4], variable gear
mesh stiffness [5], backlash influence, clutch activation function and variable input
speed, based on the functional principle of the combustion engine [6].
The numerical simulation of whole transmission was performed for run-up simulations at given gears. The technical experiment on the prototype equipment was
performed for steady-state at the given gears. The loading and engine speed was
monitored in detail. The results were compared, see Fig. 3.
3 Results
In this paper, the influence of clutch activation and deactivation on dual-clutch
gearbox dynamic behaviour is investigated. Based on the functional principle of
the dual-clutch gearbox, the time of activation and deactivation for the sensitivity
study purposes is set between 0.1 and 0.3 s. All combinations are simulated, see
Fig. 4. The simulations were performed for the carried torque range 100 and 200
Nm.
When the time between maximal value of the activation and deactivation function
is decreasing, the clutch carried torque is increasing. During the transient shift phase,
both clutches are partially engaged. The main goal during tuning of the gear shift is to
find a good balance between carried torque of the clutch 1 and 2. The carried torque
before and after shift process must correspond to the gear ratio between two gears,
in this case, i = 0.63, see Fig. 5. The maximal value of torque oscillation during
gear shift is changing based on the simulated variant. With decreasing of shifting
time the higher peaks of the carried torque occur, see Fig. 6. Another sensitivity
study is performed for different values of loading torque. Results in Fig. 7 show, that
with increasing loading torque through the whole gearbox the peaks in clutch carried
torque are decreasing.
The difference from the NVH point of view can be observed in the Multispectrum
diagram, where the critical locations are usable for comparison. Short shifting time
significantly affects the surface normal velocity, due to mentioned higher peaks of the
carried torque and thus of the structure excitation as well. This impact-like character
of excitation causes wide frequency range vibration, see Fig. 8, (time 2 ÷ 2.3 s).
A. Prokop et al.
2.3 Multibody Simulation
First, the virtual prototype of the heavy-duty gearbox was created. The parametrical
open code written in ADAMS was modified to use for complex structure and the script
was extended for shift application. The virtual prototype includes flexible bodies of
key component, stiffness and damping representation of bearings [4], variable gear
mesh stiffness [5], backlash influence, clutch activation function and variable input
speed, based on the functional principle of the combustion engine [6].
The numerical simulation of whole transmission was performed for run-up simulations at given gears. The technical experiment on the prototype equipment was
performed for steady-state at the given gears. The loading and engine speed was
monitored in detail. The results were compared, see Fig. 3.
3 Results
In this paper, the influence of clutch activation and deactivation on dual-clutch
gearbox dynamic behaviour is investigated. Based on the functional principle of
the dual-clutch gearbox, the time of activation and deactivation for the sensitivity
study purposes is set between 0.1 and 0.3 s. All combinations are simulated, see
Fig. 4. The simulations were performed for the carried torque range 100 and 200
Nm.
When the time between maximal value of the activation and deactivation function
is decreasing, the clutch carried torque is increasing. During the transient shift phase,
both clutches are partially engaged. The main goal during tuning of the gear shift is to
find a good balance between carried torque of the clutch 1 and 2. The carried torque
before and after shift process must correspond to the gear ratio between two gears,
in this case, i = 0.63, see Fig. 5. The maximal value of torque oscillation during
gear shift is changing based on the simulated variant. With decreasing of shifting
time the higher peaks of the carried torque occur, see Fig. 6. Another sensitivity
study is performed for different values of loading torque. Results in Fig. 7 show, that
with increasing loading torque through the whole gearbox the peaks in clutch carried
torque are decreasing.
The difference from the NVH point of view can be observed in the Multispectrum
diagram, where the critical locations are usable for comparison. Short shifting time
significantly affects the surface normal velocity, due to mentioned higher peaks of the
carried torque and thus of the structure excitation as well. This impact-like character
of excitation causes wide frequency range vibration, see Fig. 8, (time 2 ÷ 2.3 s).