Marine Vessel Propulsion Shift Control Reducing Drive Unit Load
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Solution Overview
Problem
In marine vessel propulsion systems with electronic shift drive mechanisms, the misfire control of the spark plug is initiated too early after a shift-out operation, leading to a lag between the start of misfire control and actual engine speed decrease, resulting in increased loads on the shift drive unit and mechanism during the transition from transmitting to cut-off states.
Innovation Solution
A control unit is implemented to delay the start of the shift drive unit's operation by a predetermined time period after initiating misfire control, ensuring the engine speed has decreased before switching from the transmitting to the cut-off state, thereby reducing loads on the shift drive unit and mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If misfire control is started immediately after shift-out operation detection, then engine speed decreases faster, but the shift drive unit experiences large loads during switching
Solution Approach 1:
The control unit starts misfire control before actuating the shift drive unit. This preliminary action causes the engine speed to decrease in advance, so that when the shift mechanism switches from transmitting to cut-off state, the load on the shift drive unit is already reduced, preventing large loads during switching
2Loss of time
If shift drive unit is actuated immediately after shift-out operation, then shift-out execution is faster, but large loads are applied to the shift mechanism unit
Solution Approach 1:
The control unit delays actuation of the shift drive unit until after misfire control has been initiated and engine speed has started to decrease. This timing ensures that the shift mechanism switches under reduced load conditions, minimizing the load on the shift drive unit while maintaining efficient shift-out execution
3Ease of operation
If misfire control is delayed to reduce load on shift drive unit, then shift-out operation becomes smoother, but power consumption of shift drive unit increases
Solution Approach 1:
The control unit initiates misfire control as the first action, which reduces engine speed and consequently reduces the load on the shift mechanism. This allows the shift drive unit to operate more efficiently with lower power consumption while achieving smooth shift-out operations under reduced load conditions
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 configuration allows for smooth and reliable shift-out operations with reduced load on the shift drive unit and mechanism, minimizing power consumption and user recognition of lag in shift-out execution.
Implementation Method 1
an engine (2) arranged to generate a driving force by combustion of a fuel by an ignition unit (18)
Implementation Method 2
the control unit temporarily lowers an engine speed by starting misfire control of the ignition unit (18)
Data Source
AI summary
A marine vessel propulsion device includes an engine arranged to generate a driving force by combustion of a fuel by an ignition unit, a thrust generating unit arranged to be driven by the driving force of the engine to generate thrust underwater, a shift mechanism unit arranged to switch between a transmitting state of transmitting the driving force of the engine to the thrust generating unit and a cut-off state of cutting off the driving force of the engine from the thrust generating unit, a shift drive unit arranged to drive the shift mechanism unit, and a control unit arranged to electrically control the shift drive unit based on a position of a shift operational unit that is arranged to be operated by a user to perform a shifting operation to a first shift position corresponding to the transmitting state, and a second shift position corresponding to the cut-off state. When changing from the first shift position to the second shift position, the control unit temporarily lowers an engine speed by starting misfire control of the ignition unit. After the start of the misfire control, the control unit controls the shift drive unit such that the shift mechanism unit starts the switching from the transmitting state to the cut-off state after a delay time period corresponding to a time from the start of misfire control to a point in time when the ignition unit actually starts to misfire.