Ship Propulsion Control for Fuel and NOx Optimization
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Solution Overview
Problem
Contemporary ships with controllable pitch propellers often consume excessive fuel and produce high NOx emissions due to inappropriate engine operation settings, leading to increased fuel costs and environmental harm.
Innovation Solution
A method for controlling ship propulsion by adjusting engine torque and speed to maintain fuel consumption within a desired range, while monitoring and reducing NOx emissions by determining actual NOx content in exhaust gases and adjusting engine operation based on geographical emission standards, and optionally managing top pressure to prevent engine damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine operates at high torque and speed to maintain ship speed, then productivity is improved, but fuel consumption increases and NOx emissions worsen
Solution Approach 1:
The control system continuously monitors actual NOx emissions from the engine and uses this feedback to dynamically adjust torque and engine speed. The system compares measured NOx levels against threshold values and automatically modifies operating parameters to maintain productivity while keeping emissions within acceptable limits
Solution Approach 2:
The system changes engine operating parameters (torque and speed) based on actual NOx measurements. By dynamically adjusting these parameters rather than operating at fixed high settings, the system maintains ship speed while reducing NOx emissions through optimized engine operation points
2Productivity
If the engine operates at high torque to maintain ship speed, then productivity is improved, but fuel consumption increases
Solution Approach 1:
The control system uses feedback from NOx sensors to determine optimal engine operating points that balance speed requirements with fuel efficiency. By continuously monitoring emissions and adjusting parameters accordingly, the system avoids unnecessary fuel consumption while maintaining required productivity
Solution Approach 2:
The system dynamically changes engine torque and speed parameters based on actual operating conditions and NOx levels. This allows the engine to operate at optimal fuel efficiency points rather than constantly at high torque settings, reducing fuel consumption while maintaining ship speed
3Object-generated harmful factors
If the torque is reduced to lower NOx emissions, then environmental harm is reduced, but ship speed decreases
Solution Approach 1:
The system dynamically adjusts torque and speed based on real-time NOx measurements rather than using fixed reduction settings. This allows the system to maintain ship speed when NOx levels are acceptable and only reduce torque when emissions exceed thresholds, balancing environmental requirements with productivity
Solution Approach 2:
The system changes engine parameters dynamically based on actual NOx levels. When NOx emissions are within acceptable ranges, the engine operates at higher torque for maintained speed. When emissions exceed thresholds, the system adjusts parameters to reduce NOx while minimizing impact on ship speed
Data Source
AI summary
The present disclosure relates to a method for controlling the propulsion of a ship (10). The ship (10) comprises an engine (5) and a controllable pitch propeller (7), wherein torque and engine speed are adjusted to correspond to an output set point value. The adjustment is such that the ship (10) is operated in an operating condition with an engine speed of the engine (5) and a propeller pitch of the controllable pitch propeller (7) such that the fuel consumption of the ship (10) is brought and/or held within a desired fuel consumption range. The method comprises determining a top pressure value indicative of a top pressure in at least one cylinder (9) and reducing the torque of the engine (5) upon detection that the lop pressure value exceeds a top pressure threshold value.