Straddle Vehicle Throttle Control for Shift-Down Comfort
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Solution Overview
Problem
Existing straddle-type vehicles, such as motorcycles, face discomfort during shift-down operations due to throttle control that prioritizes smooth gear shifting over rider intent, leading to unintended engine braking and unnatural vehicle behavior.
Innovation Solution
A straddle-type vehicle with a controller that temporarily restricts power transmission through the clutch and executes throttle control to increase engine speed, using first and second throttle control units to set engine speeds lower or closer to the shift-down completion speed, depending on the braking system's operating state, thereby managing engine braking and ensuring comfortable travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If throttle control is executed to increase engine speed during shift-down operation, then smooth gear shifting is achieved, but unintended engine braking occurs against rider intent
Solution Approach 1:
The controller changes the throttle valve opening parameter based on braking operation detection. When braking is detected, the throttle opening is set to a smaller value compared to when braking is not detected, thereby adjusting engine speed increase behavior to match rider intent while still achieving smooth shifting
Solution Approach 2:
The controller detects rider braking operations through the brake operation sensor and uses this feedback information to adjust throttle control strategy. This closed-loop feedback ensures that throttle control during shift-down aligns with rider intent expressed through braking actions
2Stability of the object's composition
If engine speed is increased to shift-down completion speed, then gear shifting smoothness is improved, but engine braking effect increases causing unnatural vehicle behavior
Solution Approach 1:
The controller adjusts the throttle valve opening parameter based on braking operation status. When braking is detected, a smaller throttle opening is applied, which limits engine speed increase and thereby reduces the engine braking effect that would otherwise occur during shift-down operation
3Speed
If throttle valve opening is increased during shift-down, then engine speed increases smoothly, but vehicle deceleration control against rider intent occurs
Solution Approach 1:
The system uses brake operation detection as feedback to adjust throttle control. When the brake operation sensor detects rider braking input, the controller modifies throttle valve opening to prevent unintended deceleration, ensuring vehicle deceleration control aligns with rider intent
Solution Approach 2:
The throttle valve opening parameter is dynamically adjusted based on braking operation detection. Smaller opening values are used when braking is detected, thereby controlling engine speed increase to match rider deceleration intent
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3E
AI summary
In the first mode, a parameter of control of a throttle valve is set in shift-down operation so that an engine speed may increase to a first rotation speed lower than a shift-down completion speed. In the second mode, the parameter of control of the throttle valve is set in shift-down operation so that the engine speed may increase to a second rotation speed having a difference smaller than that of the first rotation speed from the shift-down completion speed. A controller selects one of the first mode and the second mode according to an operating state of a braking system. Thereby, a straddle-type vehicle by which comfortable traveling may be obtained during shift-down operation may be realized.