Engine Throttle Control System Linearity
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Solution Overview
Problem
Conventional engine throttle control systems, particularly throttle-by-wire systems, face challenges in maintaining throttle linearity between the operation amount of the throttle operating device and the intake air amount, especially when the throttle opening degree enters the middle or large opening region, leading to unstable correlation and variation in intake air with the same operation amount.
Innovation Solution
The engine throttle control system includes an operation amount detecting unit, a basic throttle opening degree computing unit, a throttle opening degree additional value computing unit, and a control unit that adjusts the throttle opening degree by adding an additional value when the operation amount is within a small region, and uses a water-temperature sensor to set the additional value, ensuring linearity regardless of the throttle opening degree required for idle operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the throttle opening degree is controlled by simply adding the idle operation throttle opening degree and the driver's requested throttle opening degree, then the control system is simple to implement, but the throttle linearity deteriorates in the middle or large opening region
Solution Approach 1:
The patent segments the throttle control into two distinct components: a basic throttle opening degree calculated from the driver's operation amount, and a correction value stored in a lookup table that compensates for non-linearities. This segmentation allows the system to maintain simplicity while achieving accurate linear control across different throttle regions.
Solution Approach 2:
The patent pre-calculates and stores correction values in a lookup table during the design phase, based on the specific characteristics of the throttle valve and idle air control valve. This preliminary action eliminates the need for complex real-time calculations, maintaining system simplicity while ensuring accurate throttle linearity during operation.
2Speed
If the throttle opening degree is controlled by adding idle and driver-requested throttle opening degrees, then the control response is fast, but the intake air amount varies even with the same operation amount due to the magnitude of idle throttle opening degree
Solution Approach 1:
The patent implements a feedback mechanism where the actual throttle opening degree and intake air amount are monitored, and correction values are applied based on pre-stored data that accounts for the interaction between idle air control and driver input. This ensures stable and predictable intake air delivery while maintaining fast response characteristics.
3Manufacturing precision
If a complex control calculation is used to maintain throttle linearity, then the throttle linearity is improved, but the device complexity increases
Solution Approach 1:
The patent performs complex control calculations in advance during the design phase, storing the results in a lookup table. During actual operation, the system simply retrieves pre-calculated correction values based on the current throttle region, eliminating the need for complex real-time mathematics while maintaining high throttle linearity.
Solution Approach 2:
The patent replaces complex real-time mathematical calculations with a simple lookup table retrieval operation. This substitution of computational mechanics with data retrieval significantly reduces processing requirements and system complexity while maintaining accurate throttle control.
Data Source
AI summary
An operation amount detecting unit 17 detects an operation amount of a throttle grip from a zero position. A basic throttle opening degree computing unit 18 computes a basic throttle opening degree corresponding to the operation amount. A throttle opening degree additional value computing unit 20 outputs as a target throttle opening degree a value obtained by adding the basic throttle opening degree with a throttle opening degree additional value corresponding to the operation amount when the operation of the throttle grip is performed within a small operation region corresponding to an idle operation. The throttle opening degree additional value computing unit 20 outputs as the target throttle opening degree the basic throttle opening degree when the operation of the throttle grip is performed without the small operation region.