Atmospheric Pressure Learning for Engine Control
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Solution Overview
Problem
Controlling internal combustion engines without an intake throttle valve angle sensor is challenging due to unreliable sensor data, especially at varying altitudes, leading to incorrect atmospheric pressure estimation and component variations.
Innovation Solution
A method using a crankshaft position sensor and intake air pressure sensors to determine rotational speed and atmospheric pressure, applying filters to learn and adjust pressure ratios, and controlling the engine based on these values to determine the state of the air intake throttle valve, eliminating the need for a throttle valve position sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor for detecting the intake throttle valve position is used, then engine load information can be obtained, but the sensor is difficult to incorporate and not reliable over time
Solution Approach 1:
The patent removes the intake throttle valve position sensor from the system and replaces it with a solution based on intake air pressure measurements and atmospheric pressure learning. The control unit determines throttle valve position indirectly by comparing intake air pressure at different crankshaft positions, eliminating the need for the unreliable sensor while maintaining engine load detection capability.
Solution Approach 2:
The patent introduces atmospheric pressure learning as an intermediary mechanism. By learning and storing atmospheric pressure values over time, the system creates a reference that enables indirect determination of throttle valve position through pressure ratios, serving as a mediator between the available sensors and the required control information.
2Reliability
If intake air pressure is used for engine load control, then sensor reliability improves, but atmospheric pressure estimation becomes incorrect at varying altitudes
Solution Approach 1:
The patent implements preliminary atmospheric pressure learning during engine operation. The control unit continuously learns and updates atmospheric pressure values by analyzing intake air pressure measurements at specific crankshaft positions, building an accurate atmospheric pressure reference before it is needed for throttle position determination, thus accounting for altitude variations.
Solution Approach 2:
The patent employs feedback through atmospheric pressure learning. The control unit uses intake air pressure measurements to continuously refine and update the atmospheric pressure estimate, creating a self-correcting system that adapts to changing altitude conditions and maintains measurement precision over time.
3Device complexity
If atmospheric pressure learning is performed only when engine is switched off, then determination is simplified, but differentiation between incorrect estimation and component variation is not possible
Solution Approach 1:
The patent implements continuous atmospheric pressure learning during engine operation rather than only when switched off. The control unit continuously analyzes intake air pressure measurements at different crankshaft positions and updates atmospheric pressure estimates in real-time, enabling ongoing differentiation between estimation errors and component variations while maintaining accurate pressure determination.
Data Source
AI summary
A method for controlling an internal combustion engine with a crankshaft position sensor, intake air pressure sensor and fresh air intake throttle valve, includes: determining the engine's rotational speed based on the crankshaft position derivative relative to time; determining the intake air pressure for a first crankshaft position corresponding to 180° before top dead center; determining the intake air pressure for a second crankshaft position corresponding to 390° before top dead center; determining an atmospheric pressure learning pressure threshold based on the engine's rotational speed; determining whether the difference between the intake air pressures for the first and second crankshaft positions is below the atmospheric pressure learning pressure threshold; if so, commanding atmospheric pressure learning by applying a first-order filter to the intake air pressure for the second crankshaft position; and controlling the internal combustion engine as a function of the learned atmospheric pressure value.