Hybrid Engine Torque Compensation During Valve Lift Switching
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Solution Overview
Problem
Existing variable valve lifting systems in thermal engines cause a sudden change in engine torque during transitions between different valve lifting laws, leading to a jerky ride for passengers and inefficiencies in fuel consumption.
Innovation Solution
A process that compensates for engine torque deviations by modifying the torque produced by an electric motor in a hybrid vehicle, allowing for a smooth transition between valve lifting laws without jerking, by temporarily assisting the thermal engine during sudden changes in air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a discontinuous variable angular spread distribution system is used to modify valve lift law, then torque and power can be varied, but sudden torque change causes jolt to passengers
Solution Approach 1:
An intermediary control system is introduced that detects sudden torque changes caused by valve lift law transitions and activates compensatory measures (ignition advance modification or electric motor torque adjustment) to smooth out the torque delivery to the drivetrain, preventing passenger jolt while maintaining the adaptability of the valve lift system
Solution Approach 2:
The control system performs preliminary detection of valve lift law changes and preemptively adjusts ignition timing or electric motor torque before the sudden torque change affects the drivetrain, ensuring smooth transition and eliminating passenger jolt while preserving torque variation capability
2Object-affected harmful factors
If ignition advance is modified to reduce combustion efficiency during sudden airflow increase, then torque jump is smoothed, but fuel consumption increases
Solution Approach 1:
An electric motor acts as an intermediary to compensate for torque deviations during valve lift law transitions. The electric motor provides or absorbs torque to maintain smooth drivetrain operation, eliminating the need to deteriorate combustion efficiency and thus avoiding increased fuel consumption while still smoothing torque jumps
Solution Approach 2:
The system dynamically changes the torque contribution parameter of the electric motor in response to valve lift law transitions. By adjusting the electric motor's torque output parameter, the system compensates for airflow-induced torque deviations without modifying combustion parameters, thereby maintaining optimal fuel efficiency while smoothing torque delivery
3Object-affected harmful factors
If ignition advance is increased to improve combustion efficiency during sudden airflow decrease, then torque is increased, but the method is difficult to apply when airflow decreases
Solution Approach 1:
The electric motor serves as a versatile intermediary that can compensate for torque deviations in both directions (airflow increase and decrease). Unlike ignition advance modification which is limited in its applicability, the electric motor can provide or absorb torque as needed, making the compensation method universally applicable to all airflow transition scenarios
Solution Approach 2:
The electric motor provides multi-functional capability by being able to compensate for torque deviations regardless of the direction of airflow change. The same electric motor compensation mechanism that works for airflow increase also effectively addresses airflow decrease scenarios, eliminating the limitations of ignition advance-based methods and providing universal applicability across all operating conditions
Data Source
Figure 1~2
Figure 3
AI summary
This method for compensating for engine torque differences due to a change in valve lift and airflow in a combustion engine of a hybrid vehicle comprising an electric motor capable of operating in generator and alternator mode, said vehicle being equipped with a discontinuous variable angle valve timing system capable of modifying the valve lift of the combustion engine, comprises the following steps: - Identification (step 21) of a desired change in torque by the driver; - Determination (step 22) of the torque difference between the torque of the combustion engine before and after the change in torque; - Compensation (step 23) of the torque difference of the combustion engine by modifying the torque produced by the electric motor so as to obtain a torque substantially equal to the torque before the change in torque, while the airflow in the combustion engine does not allow this torque to be obtained without the electric motor.