Electronic Throttle Control for Linear Torque Response
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Solution Overview
Problem
Existing engine control systems for straddle-type vehicles fail to provide a linear increase in engine torque with accelerator displacement across all engine speeds, leading to poor acceleration feeling and riding comfort, especially at low speeds, and require additional components like sub throttle valves to avoid over venturi effects.
Innovation Solution
An engine control device with an electronically controlled throttle valve that adjusts throttle opening based on accelerator displacement and engine speed, ensuring engine torque increases with accelerator operation for all speeds, approximating maximum torque at low speeds and gradually increasing with further displacement, using map data to determine optimal throttle positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sub throttle valve is provided upstream from the throttle valve to adjust the opening, then the over venturi effect is avoided and intake efficiency increases, but the size of the throttle body and manufacturing cost increase
Solution Approach 1:
The patent extracts the sub-throttle valve component from the system and replaces it with an electronic control mechanism that adjusts the main throttle valve opening based on engine speed and accelerator position, thereby eliminating the need for additional hardware while maintaining intake efficiency
Solution Approach 2:
The patent replaces the mechanical sub-throttle valve system with an electronically controlled throttle valve system that uses sensors and a control unit to regulate airflow, substituting mechanical complexity with electronic control
2Reliability
If the throttle valve opening is limited to avoid over venturi effect, then torque decrease is avoided, but engine torque becomes constant and no torque control can be executed
Solution Approach 1:
The patent implements dynamic throttle control where the optimal throttle opening is continuously adjusted based on real-time engine speed and accelerator position, allowing the system to maintain torque stability at low speeds while enabling full torque control range at higher speeds
Solution Approach 2:
The patent changes the control parameters by using engine speed and accelerator position as input variables to dynamically determine throttle opening, replacing the static throttle limitation approach with a multi-parameter dynamic control strategy
3Productivity
If the target amount of intake air is gradually increased in proportion to accelerator opening, then engine output increases linearly, but the response of engine output is poor when accelerator displacement is small
Solution Approach 1:
The patent changes the control approach by using engine speed as an additional parameter alongside accelerator position to determine throttle opening, allowing the system to provide rapid response at low accelerator positions while maintaining linear engine output characteristics across the full operating range
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
This solution provides responsive engine control and improved riding comfort by ensuring engine torque increases with accelerator displacement across all engine speeds, offering a better acceleration feeling and eliminating torque loss, while avoiding the need for additional components like sub throttle valves.
Implementation Method 1
the flow of air passing through an intake passage accelerates and intake efficiency increases
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
A method and device for controlling an engine, in particular of a straddle-type vehicle, in which an engine torque is controlled by electronically controlling a throttle opening in response to a displacement of an accelerator, wherein the throttle opening is controlled such that for all engine speeds the engine torque increases in response to an increase in the accelerator displacement.