Sliding Camshaft Actuator Cold Start Heating
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Solution Overview
Problem
Sliding camshaft actuators in variable valve lift systems experience sluggish performance in cold environments due to increased electrical resistance, leading to inefficient engine operation until the actuators warm up.
Innovation Solution
A method involving the application of reverse voltage to the magnetic field generating coils to heat the piston armature, magnet, and actuator pin, utilizing a control module to detect cold start conditions and maintain the reverse energizing voltage for a predetermined period to reduce friction and electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the actuator operates in cold environments, then the pins move more slowly, but the coil warms up and copper losses increase causing resistance to increase and pushing force to decrease
Solution Approach 1:
The system applies reverse voltage to the coil before normal operation in cold conditions to pre-heat the actuator components. This preliminary heating action prevents the performance degradation that would otherwise occur during cold operation, ensuring the pins move at appropriate speeds from the start of operation.
Solution Approach 2:
The system changes the electrical parameter of the coil by applying reverse voltage (opposite polarity) temporarily during cold conditions. This parameter change generates heat through resistive heating, which raises the temperature of the actuator components, thereby reducing copper losses and maintaining optimal electrical resistance for reliable operation.
2Reliability
If reverse voltage is applied to heat the actuator, then electrical resistance decreases and performance improves, but additional energy consumption occurs
Solution Approach 1:
The reverse voltage is applied periodically or temporarily only during cold start conditions rather than continuously. The control system monitors temperature or time since startup and applies reverse voltage only when needed to reach optimal operating temperature, thereby minimizing additional energy consumption while ensuring reliable performance during cold operation.
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
This method effectively reduces friction and electrical resistance, ensuring prompt and efficient engine operation by dissipating heat to the actuator components, thereby eliminating negative performance characteristics associated with cold starts.
Implementation Method 1
at least one magnetic field generating coil having a core, a piston armature disposed in the core of the at least one magnetic field generating coil
Implementation Method 2
creating a magnetic force attraction between the magnet and the at least one magnetic field generating coil
Implementation Method 3
maintaining the reverse energizing voltage on the at least one magnetic field generating coil for a predetermined period of time to heat the piston armature, the magnet, and the actuator pin
Implementation Method 4
dissipating heat from the at least one magnetic field generating coil to the actuator pin
Data Source
AI summary
A method for heating a sliding camshaft actuator at cold engine start wherein the sliding camshaft actuator includes at least one magnetic field generating coil having a core, a piston armature disposed in the core of the at least one magnetic field generating coil, a magnet in mechanical communication with the piston armature, and an actuator pin in mechanical communication with the magnet. The method includes detecting a cold engine start condition and reversing an energizing voltage on the at least one magnetic field generating coil when the outside temperature is below a predetermined temperature threshold. The reverse energizing voltage on the at least one magnetic field generating coil is maintained for a predetermined period of time to heat the piston armature, the magnet, and the actuator pin.