Electric Camshaft Phasing for Engine Start Synchronization
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Solution Overview
Problem
Existing methods fail to accurately determine the angular position of a camshaft with an electric continuous variable valve timing device after the engine is switched off, preventing effective synchronization and starting of the internal combustion engine.
Innovation Solution
Applying a maximum voltage to the electric actuator for a predetermined duration, initiating a safety timer, and synchronizing the engine based on the limit angular position data, with failure counter increments if synchronization is not achieved within a predetermined number of attempts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical actuator with a return spring is used to position the camshaft, then the camshaft position can be determined after engine shutdown, but the device complexity increases and the ease of operation decreases
Solution Approach 1:
The patent replaces the mechanical return spring actuator with an electric actuator. The electric actuator uses electrical signals to position the camshaft without requiring mechanical return springs or complex mechanical positioning mechanisms. The control unit sends electrical commands to the electric actuator to achieve precise camshaft positioning, thereby simplifying the mechanical structure while maintaining measurement precision through electronic control and sensor feedback.
2Measurement precision
If maximum voltage is applied to the electric actuator for a predetermined duration, then the camshaft reaches a known limit angular position for synchronization, but the duration of action increases
Solution Approach 1:
The patent applies maximum voltage to the electric actuator for a predetermined duration before engine startup to move the camshaft to a known limit angular position. This preliminary action establishes a reference position (limit position) that the control unit can use for synchronization. The predetermined duration is calculated based on the actuator's response characteristics to ensure the camshaft reaches the limit position reliably before the engine starts rotating, thereby providing accurate position reference without excessive delay.
3Reliability
If the engine synchronization is not achieved within the safety timer duration, then the failure counter is incremented and the process is reiterated, but the loss of time increases
Solution Approach 1:
The patent implements a feedback mechanism where the control unit monitors whether engine synchronization is achieved within a predetermined safety timer duration. If synchronization fails, the failure counter is incremented and the voltage application process is reiterated. The system continuously monitors the camshaft position and engine synchronization status, adjusting the voltage application timing and duration based on the outcomes of previous attempts. This feedback loop ensures reliable synchronization while minimizing time loss by learning from previous failures and optimizing the approach.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate synchronization and starting of the internal combustion engine by determining the camshaft position, even with electric actuators, thereby optimizing engine efficiency and reducing fuel consumption and emissions.
Implementation Method 1
The electric device comprises an electric actuator configured to modify the angular position of the camshaft
Data Source
AI summary
A method for starting an internal combustion engine including a camshaft provided with an electric continuous variable valve timing device. The method includes: (a) applying a maximum voltage to the electric actuator, then (b1) initiating a timer Ts during which a maximum voltage continues to be applied to said actuator and, in parallel, (b2) starting a synchronization of the combustion engine, then (c) if the timer expires before the end of the synchronization of the combustion engine, incrementing the value of the failure counter and reiterating (a) to (c) if the value of the failure counter is less than a predetermined number Nmax, otherwise, stopping the application of a voltage to the actuator, the combustion engine being synchronized.