Marine Propulsion Trim Control via Engine Speed Sensing

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Solution Overview

Problem

Boat drivers face challenges in optimizing the trim position of marine propulsion units, which affects hydrodynamic performance and efficiency, requiring manual adjustment that can divert attention from steering and throttle control.

Innovation Solution

A method and system that automatically control the trim position of a marine propulsion unit based on engine speed, using predetermined trim angles and a control unit connected to a trim actuator, allowing for independent adjustment of trim angles without direct driver input, enabling optimal performance across various speed ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the driver manually controls the trim position, then optimal hydrodynamic performance can be achieved, but the driver's attention is diverted from steering and throttle control

Engineering Contradiction:

Improvehydrodynamic performanceVSAvoiddriver attention requirement

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The trim control system operates autonomously by sensing engine speed and automatically positioning the propulsion unit at appropriate trim angles. The system serves itself by using engine speed as input to determine trim position, eliminating the need for direct driver intervention while maintaining optimal hydrodynamic performance across different operating conditions.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system continuously monitors engine speed and uses this feedback to automatically adjust the trim position. The control unit receives engine speed signals and dynamically positions the propulsion unit accordingly, creating a closed-loop control system that maintains optimal performance without requiring driver attention.

Inventive Principle:

Principle #23Feedback

2Ease of operation

If the trim position is automatically controlled based on engine speed, then driver workload is reduced, but the system complexity increases

Engineering Contradiction:

Improvedriver workloadVSAvoidcontrol system complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The control unit performs multiple functions: it senses engine speed, determines appropriate trim angles based on predetermined criteria, and controls the trim actuator. By consolidating these functions in a single control unit, the system achieves automatic trim control without proportionally increasing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system combines the trim control functionality with the existing engine management system by using the same control unit to process engine speed signals and control trim positioning. This integration approach reduces the need for separate dedicated components, thereby limiting the increase in system complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Stability of the object's composition

If the propulsion unit is trimmed too far in, then the boat can be kept stable, but drag increases and speed decreases

Engineering Contradiction:

Improveboat stabilityVSAvoidboat speed

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The system dynamically adjusts the trim position based on engine speed rather than maintaining a fixed position. At different engine speeds, the propulsion unit is positioned at different trim angles optimized for that operating condition, allowing the system to balance stability and speed requirements dynamically across the operating range.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system changes the trim angle parameter according to engine speed conditions. By varying this geometric parameter based on operating conditions, the system optimizes the balance between stability and speed, preventing the propulsion unit from being trimmed too far in during conditions where speed is prioritized.

Inventive Principle:

Principle #35Parameter changes

4Speed

If the propulsion unit is trimmed too far out, then speed can be increased, but drag increases and porpoising occurs

Engineering Contradiction:

Improveboat speedVSAvoidboat stability

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The system uses dynamic trim adjustment based on engine speed sensing to prevent excessive trim-out conditions. The control unit monitors engine speed and automatically positions the propulsion unit at appropriate angles, preventing the conditions that lead to porpoising and instability while still achieving optimal speed.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9463858B1Method and system for controlling a trim position of a marine propulsion unit

Publication Date: 2016.10.11 BRP US INC

AI summary

A method for controlling a trim position of a marine propulsion unit for propelling a watercraft has the steps of: sensing an engine speed; positioning the propulsion unit at a first trim angle when the engine speed is less than or equal to a first predetermined engine speed, the first trim angle being constant; positioning the propulsion unit at a second trim angle when the engine speed is greater than the first predetermined engine speed and less than the second predetermined engine speed; and positioning the propulsion unit at a third trim angle when the engine speed is greater than or equal to the second predetermined engine speed, the third trim angle being constant. A system for controlling a trim position of a marine propulsion unit for propelling a watercraft is also disclosed.