Outboard Motor Atmospheric Pressure Estimation via Throttle Mapping
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Solution Overview
Problem
In outboard motors for small boats without a battery, estimating atmospheric pressure is challenging due to unstable intake pressure values immediately after engine activation, making it difficult to achieve stable and reliable atmospheric pressure estimation.
Innovation Solution
An atmospheric pressure estimation device that includes an electronic control unit, operation state detection, intake pressure detection, and throttle opening detection, which processes throttle full-open values to determine an atmospheric pressure learning region and updates the atmospheric pressure learning value through filtering at predetermined intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If atmospheric pressure estimation is performed using intake pressure sensor immediately after engine activation, then atmospheric pressure can be obtained for engine control, but the estimation is unstable and unreliable due to unstable intake pressure values
Solution Approach 1:
The system performs preliminary actions by storing throttle full-open values at different rotation speeds in advance (creating a throttle full-open map), and determining an atmospheric pressure learning region before actual atmospheric pressure estimation is needed. This preliminary preparation enables reliable atmospheric pressure estimation even when intake pressure is initially unstable.
Solution Approach 2:
The patent introduces an intermediary approach by using throttle opening detection and rotation speed information as intermediate parameters to determine the atmospheric pressure learning region. Instead of directly relying on unstable intake pressure values immediately after activation, the system uses these intermediate measurements to guide the atmospheric pressure estimation process, improving reliability.
2Measurement precision
If atmospheric pressure sensor is installed to obtain accurate atmospheric pressure, then engine control accuracy is improved, but device complexity and cost increase
Solution Approach 1:
Instead of directly measuring atmospheric pressure with a dedicated sensor, the system creates a copy or model of atmospheric pressure behavior by storing throttle full-open values at various rotation speeds in a throttle full-open map. This mapped data serves as a reference model that enables atmospheric pressure estimation without requiring additional physical sensors.
Solution Approach 2:
The patent makes existing sensors (intake pressure sensor, throttle sensor, rotation speed sensor) perform multiple functions. These sensors originally designed for other measurement purposes are also used to determine the atmospheric pressure learning region and estimate atmospheric pressure, eliminating the need for a dedicated atmospheric pressure sensor while maintaining measurement accuracy.
3Reliability
If filtering is applied to estimated atmospheric pressure to improve stability, then atmospheric pressure estimation reliability increases, but processing time and computational load increase
Solution Approach 1:
The system applies filtering to estimated atmospheric pressure values at predetermined intervals rather than continuously. This periodic filtering approach maintains atmospheric pressure estimation stability and reliability while reducing computational load and processing time compared to continuous filtering, effectively balancing reliability with time efficiency.
Data Source
AI summary
By obtaining an atmospheric pressure learning value by applying filtering to an estimated atmospheric pressure found from an estimated atmospheric pressure map in an atmospheric pressure learning region matched in advance, and by constantly updating this atmospheric pressure learning value, stable and highly reliable atmospheric pressure estimation can be achieved. Also, a pre-set parameter value or the last atmospheric pressure learning value is used as the initial atmospheric pressure value and an unstable intake pressure value at the engine start in a battery-less state is not used. Hence, it becomes possible to provide an estimated atmospheric pressure with which high drivability is achievable by fully exploiting the engine performance as soon as the engine is started.