Outboard Motor Control for Bubble Entrainment Compensation
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Solution Overview
Problem
The existing outboard motor systems experience reduced propulsion efficiency due to bubble entrainment when reversing, leading to incongruity in operator experience and varying movement requirements, as the propeller's rotational speed increases, causing increased exhaust gas bubbles to be dragged, reducing the propulsive force.
Innovation Solution
A control apparatus that includes a judgment unit to determine propulsive force reduction and a control unit to adjust engine output, switching between normal and correction control modes based on bubble entrainment, setting a higher target rotational speed in correction mode to compensate for reduced efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the propeller's rotational speed is increased to enhance propulsion, then the propulsive force should increase, but bubble entrainment increases causing propulsion efficiency to deteriorate
Solution Approach 1:
The control apparatus changes the engine output parameter dynamically based on operating conditions. When bubble entrainment is detected (reverse direction operation), the system increases engine output beyond normal levels to compensate for the propulsion efficiency loss, thereby maintaining the required propulsive force despite the adverse conditions
2Stability of the object's composition
If the engine output is increased to maintain propulsive force during bubble entrainment, then propulsion consistency is improved, but energy consumption increases
Solution Approach 1:
The control system dynamically adjusts engine output based on real-time operating conditions detected by the judgment unit. The system applies correction control mode selectively only when bubble entrainment conditions are present (reverse direction, low forward speed), rather than maintaining high output continuously, thus achieving propulsion consistency only when needed and reducing unnecessary energy consumption
3Adaptability or versatility
If the shift position is changed to reverse direction, then the marine vessel can move backward, but bubble entrainment occurs reducing the effectiveness of the propeller
Solution Approach 1:
The control apparatus applies preliminary anti-action by detecting the reverse direction shift position and proactively increasing engine output before bubble entrainment significantly degrades performance. The judgment unit identifies reverse operation conditions and the control unit pre-compensates by increasing power output, counteracting the anticipated propulsion efficiency loss from bubble entrainment
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
The control apparatus effectively suppresses propulsive force reduction by increasing engine output when bubble entrainment occurs, ensuring consistent propulsion and reducing operator discomfort by maintaining propulsive force regardless of bubble entrainment, thus enhancing operational consistency.
Implementation Method 1
the propeller rotates (rotated forward) in a direction along which water is pushed out rearward, and a propulsive force which allows a marine vessel to move in a forward direction is generated
Implementation Method 2
the propeller is rotated (rotated reverse) in the direction opposite to the forward direction, and a propulsive force which allows a marine vessel to move in a reverse direction is generated
Implementation Method 3
Bubble entrainment occurs, by which bubbles are entrained or dragged in the propeller
Data Source
AI summary
The control apparatus controls an outboard motor having a propeller and an engine that rotates the propeller and discharges exhaust gas in water. The control apparatus includes a judgment unit arranged to determine a reduction in the propulsive force of the outboard motor due to in-water exhaust of the engine, and a control unit arranged to control the engine such that, when the judgment unit determines that a reduction in the propulsive force occurs, the output of the engine is increased as compared to when the judgment unit determines that a reduction in the propulsive force does not occur.