Marine Engine RPM Control for Warm-Up and Smooth Shifting
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Solution Overview
Problem
Current marine propulsion systems face challenges in reducing engine warm-up time and increasing battery charge rate while maintaining operating comfort during gear shifts, as existing methods either stall the engine or cause noise and shock during transitions.
Innovation Solution
A method and system that adjust engine RPM setpoints based on coolant temperature and battery voltage thresholds, increasing RPM during idle to warm up the engine and charge the battery, and then reducing RPM during gear shifts to facilitate smooth transitions by decreasing torque and load on the gear system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If engine RPM is increased during idle to warm up the engine and charge the battery, then engine warm-up time is reduced and battery charge rate is increased, but noise and shock during gear shifts increases
Solution Approach 1:
The system dynamically adjusts the engine RPM setpoint based on operating conditions. During idle, the RPM setpoint is increased above the baseline to warm up the engine and charge the battery. When a gear shift is detected, the RPM setpoint is temporarily reduced to facilitate smooth shifting, then restored after the shift completes. This dynamic adjustment resolves the contradiction by allowing high RPM during idle for faster warm-up and charging, while temporarily reducing RPM during gear shifts to minimize noise and shock.
Solution Approach 2:
The invention changes the engine RPM parameter based on detected conditions. The control module monitors for gear shift events and modifies the RPM setpoint accordingly - increasing it during idle for efficient warm-up and battery charging, then decreasing it during gear shift transitions to reduce harmful noise and shock, and restoring it after the shift. This parameter change strategy allows the system to optimize performance at different operational phases.
2Use of energy by moving object
If engine RPM is increased during idle to increase battery charge rate, then battery voltage is increased, but torque and load on the gear system increases making shifts difficult
Solution Approach 1:
The control module dynamically modifies the engine RPM setpoint based on operational phase. During idle, the RPM setpoint is increased to enhance battery charging. When a gear shift is detected, the RPM setpoint is temporarily reduced to decrease torque and load on the gear system, facilitating smooth shifting. After the shift completes, the RPM setpoint is restored. This dynamic adjustment resolves the contradiction by allowing high RPM for efficient energy transfer to the battery during idle, while temporarily reducing RPM during gear shifts to ease operation.
Solution Approach 2:
The system performs preliminary detection of gear shift events and proactively reduces the RPM setpoint before the actual shift occurs. This preliminary action decreases torque and load on the gear system in advance, making the shift smoother and easier to execute. After the shift is detected as complete, the RPM setpoint is restored to its previous elevated value to resume efficient battery charging. This preliminary action prevents the contradiction from manifesting during the shift event.
Data Source
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AI summary
A method of controlling engine RPM in a marine propulsion device having an engine (3) that effectuates rotation of a propulsor (9) through a gear system (5) that shifts amongst a forward gear position, a reverse gear position, and a neutral position, includes determining that a coolant temperature is below a temperature threshold or that a battery voltage is below a voltage threshold, and then increasing an engine RPM setpoint by a compensation RPM amount while the engines (3) remains in an idle state in order to increase the coolant temperature or the battery voltage. When a shift instruction is detected to transition the gear system (5) from the reverse gear position to the neutral position or from the forward gear position to the neutral position, the engine RPM setpoint is reduced by a shift RPM reduction amount during transition of the gear system, and the engine (3) is controlled according to the engine RPM setpoint.