Solenoid Injector Valve Control for Low-Ripple End Activation
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Solution Overview
Problem
Existing control systems for solenoid injector valves in internal combustion engines face challenges in minimizing shot-to-shot variation and current ripple, leading to inaccuracies and increased power losses due to random statistical errors and high switching frequencies.
Innovation Solution
A valve controller with an increased switching frequency during the ending-of-activation phase to reduce current ripple, implemented with an application-specific integrated circuit (ASIC) and state machine, transitions the valve from a hold phase to an ending-of-activation phase upon a specific input signal edge, maintaining reduced power losses by limiting the duration of this phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the switching frequency of drive transistors is increased during the hold phase to reduce current ripple, then the shot-to-shot variation (jitter) is reduced, but the power losses increase
Solution Approach 1:
The switching frequency is dynamically adjusted based on the operational phase: high frequency during the ending-of-activation phase to minimize jitter, and reduced frequency during the hold phase to minimize power losses. This dynamic adaptation resolves the contradiction by optimizing frequency for each specific operational requirement.
Solution Approach 2:
The activation profile is segmented into distinct phases (hold phase and ending-of-activation phase), each with different switching frequency requirements. The hold phase uses lower frequency to reduce power loss, while the ending-of-activation phase uses higher frequency to reduce current ripple and jitter, thereby resolving the overall contradiction.
2Measurement precision
If the duration of the ending-of-activation phase is extended to further reduce current ripple, then the jitter is reduced, but the activation time increases
Solution Approach 1:
Instead of extending the ending-of-activation phase indefinitely to eliminate all ripple, the solution applies partial action by limiting the phase duration to a predetermined time. This partial application of high-frequency switching is sufficient to achieve acceptable jitter reduction without excessively extending the total activation duration.
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 approach reduces jitter and improves accuracy and repeatability of valve activation, minimizing power losses while maintaining the duration of the hold phase, resulting in more precise control of solenoid injector valves.
Implementation Method 1
Solenoid actuators for (direct) injection valves and intake valves are operated by controlling the current through its coil (which behaves as a resistive-inductive load)
Implementation Method 2
The ending of activation phase is achieved by reducing the current ripple in the solenoid coil of the injector valve actuator
Data Source
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Figure 3
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AI summary
A valve controller and method for controlling a valve having a solenoid are disclosed, including receiving a least one input signal, detecting a first edge of the at least one signal and in response to the detection activating the valve. Activating the valve includes activating the valve in a rise-to-peak phase during which the valve is opened, a hold phase following the rise-to-peak phase during which the valve remains open and a current level of the valve is less than a current level of the valve during the rise-to-peak phase, and an ending-of-activation phase following the hold phase during which current ripple in the valve is less than the current ripple in the valve during the hold phase.