Estimating Bounce Back Angle of Stopped Engine
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Solution Overview
Problem
Existing methods for determining the stopped engine crank angle in internal combustion engines fail to accurately account for bounce back angles, leading to inefficiencies in engine restarting and increased emissions, as they do not reliably detect engine reversal or consider the effect of engine bounce back.
Innovation Solution
An engine control system utilizing a crank sensor and controller to determine the bounce back angle by analyzing crank speed decreases and time intervals between crank pulses, indicating engine reversal when a crank speed decrease exceeds a threshold, allowing for accurate estimation of the stopped engine crank angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If variable reluctance sensors are used to determine crank angle and speed, then the system is economical, but the sensor cannot detect engine reversal direction
Solution Approach 1:
The patent introduces an intermediary computational method that processes the sensor output signals to detect engine reversal. Instead of replacing the economical VR sensor with a directional sensor, the system uses software-based analysis of the existing sensor signals (comparing consecutive crank angle positions and detecting reverse rotation patterns) to determine reversal events, thus maintaining sensor cost effectiveness while achieving directional detection capability
Solution Approach 2:
The patent replaces the need for mechanically complex directional sensors with a software-based detection algorithm. The reversal detection is achieved through computational analysis of crank angle position changes over time, substituting mechanical sensor complexity with electronic signal processing to identify when the crankshaft rotates in reverse direction
2Device complexity
If engine bounce back is not accounted for in stopped engine crank angle estimation, then the estimation process is simpler, but the accuracy of stopped engine crank angle is reduced
Solution Approach 1:
The patent applies preliminary action by detecting and compensating for bounce back events before they affect the final stopped engine crank angle calculation. The system monitors for reversal conditions during the engine coast-down phase, identifies bounce back events, and adjusts the crank angle estimation accordingly before the engine comes to a complete stop, ensuring accurate final position determination
Solution Approach 2:
The patent implements feedback by continuously monitoring crank angle position and crank speed during engine deceleration, detecting when reversal occurs, and using this information to correct the stopped engine crank angle estimation. The system feeds back the detected bounce back angle to adjust the final crank angle calculation, improving accuracy by accounting for the reverse rotation that occurs during coast-down
3Device complexity
If existing reversal detection methods using time interval ratios are used, then the detection method is simple, but it fails to detect all reversal conditions including single pulse reversals
Solution Approach 1:
The patent applies dynamics by implementing an adaptive detection algorithm that responds to varying engine operating conditions. Instead of using fixed time interval ratios, the system dynamically adjusts detection parameters based on current crank speed and acceleration, allowing reliable detection of reversals across different engine states including single-pulse reversals that occur during rapid deceleration or bounce back events
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively determines the bounce back angle, enabling more efficient engine restarting and reduced emissions by accurately accounting for engine reversal and bounce back, improving the accuracy of stopped engine crank angle estimation.
Implementation Method 1
variable reluctance (VR) type sensors
Implementation Method 2
Hall effect type sensors
Implementation Method 3
inductive type sensors
Data Source
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AI summary
An engine control system, controller, and method for estimating a bounce back angle of an internal combustion engine. Typical crank sensors do not indicate crank direction, a feature that would be useful to determine if an engine reversal occurs leading to the engine accumulating a bounce back angle. A crank sensor signal is analyzed as the engine coasts to a stop so an engine reversal can be detected. After an engine reversal is detected, the crank sensor signal is analyzed to determine the bounce back angle. Engine reversal is detected by determining that the crank shaft has decelerated by more than a threshold value, or that the crank shaft has decelerated and then subsequently accelerated.