Straddle-Type Vehicle Throttle Control for Speed Limiting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Straddle-type vehicles face challenges in preventing engine and vehicle speeds from exceeding prescribed values without deteriorating ride comfort, as existing techniques often result in decelerating feelings and potential speed exceedance.
Innovation Solution
A straddle-type vehicle equipped with an electronic control throttle valve and a control apparatus that adjusts the throttle opening degree to maintain or increase it until a predetermined speed is reached, then decreases it if the speed exceeds this value, ensuring the engine or vehicle speed does not surpass the prescribed limit without compromising ride comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control for decreasing the opening degree of the throttle valve is started when the speed reaches the prescribed value, then the engine rotating speed or the vehicle speed is limited such that the speed does not exceed the prescribed value, but the ride comfort deteriorates due to sudden decelerating feeling
Solution Approach 1:
The control starts decreasing the throttle valve opening degree before the prescribed speed is reached (at a predetermined speed lower than the prescribed value). This preliminary action prevents the speed from exceeding the prescribed value while avoiding sudden deceleration, thereby maintaining ride comfort.
Solution Approach 2:
The control dynamically adjusts the throttle valve opening degree based on the detected speed. When the speed exceeds the predetermined value, the opening degree is gradually decreased to limit the speed increase, providing a smooth and comfortable deceleration experience.
2Reliability
If the engine output is limited due to cutting or reducing the engine ignition or due to stopping of the fuel supply, then the speed does not exceed the prescribed value, but the combustion stability deteriorates and exhaust performance worsens
Solution Approach 1:
Instead of cutting ignition or stopping fuel supply, the control changes the throttle valve opening degree parameter to limit engine output. This approach maintains continuous combustion and fuel supply, preserving combustion stability and exhaust performance while still achieving speed limitation.
3Reliability
If the opening degree of the throttle valve is reduced lower than a standard opening degree, then the air intake amount is reduced and the engine output is limited, but the combustion stability deteriorates compared to conventional techniques
Solution Approach 1:
The throttle valve opening degree is decreased before the prescribed speed is reached, allowing the engine to operate in a more stable combustion range while still limiting the maximum speed. This preliminary reduction avoids the unstable combustion conditions that occur when the throttle is sharply closed at high speeds.
Data Source
AI summary
A straddle-type vehicle includes an engine, an air intake pipe, a throttle valve being controlled in accordance with an operation amount of an accelerator grip, an engine rotating speed detector or a vehicle speed detector, and an electronic control unit (ECU). The ECU increases the opening degree of the throttle valve or maintains the opening degree at a constant value until the engine rotating speed reaches a set rotating speed which is smaller than a prescribed rotating speed, but if the engine rotating speed exceeds the set rotating speed, the ECU reduces the opening degree of the throttle valve irrespective of operation of the accelerator grip.