Electronic Throttle Actuator Layout in a Single-Cylinder Engine
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Solution Overview
Problem
Existing straddle-type vehicles with electronically controlled throttles face challenges in accommodating the actuator without increasing vehicle size due to the larger size of the electronically controlled throttle compared to mechanical throttles, leading to potential interference with peripheral components.
Innovation Solution
The actuator of the electronically controlled throttle is positioned such that its upper edge aligns with the lower edge of the suspension bracket and rear edge aligns with the front edges of the body frames, allowing it to be compactly housed in the narrow rear space surrounded by the body frames and suspension bracket, thus avoiding an increase in vehicle size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electronically controlled throttle is adopted instead of a mechanical throttle, then the throttle control precision and responsiveness are improved, but the actuator size increases making it difficult to accommodate in the narrow space behind the cylinder head
Solution Approach 1:
The actuator is repositioned from the conventional location behind the cylinder head to the lower space between the crankcase and the cylinder, utilizing an previously underutilized dimensional space. This spatial reconfiguration allows the larger electronically controlled actuator to fit without increasing overall vehicle dimensions.
Solution Approach 2:
The actuator is nested within the lower space formed by the crankcase and cylinder assembly, effectively utilizing the vertical space between these components. This nesting approach allows the actuator to be accommodated within the existing engine envelope without requiring additional vehicle space.
2Length of stationary object
If the actuator is positioned closer to the cylinder head to save space, then the vehicle size is reduced, but the actuator may be exposed to high temperatures causing heat damage
Solution Approach 1:
The actuator is positioned in a specific local region (lower space between crankcase and cylinder) that has favorable thermal characteristics. This location provides adequate thermal isolation from the high-temperature cylinder head while still maintaining compact overall vehicle dimensions.
Data Source
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AI summary
A single-cylinder engine (40) includes a cylinder and a cylinder (42) and a cylinder head (43) stacked on an upper portion of a crankcase (41), and an electronically controlled throttle (61) interposed in an intake passage (56) behind the cylinder head. The vehicle body frame includes a pair of main frames (12) extending rearward from a head pipe (11), and rear portions of the pair of main frames form a pair of body frames (13) bent downward behind the cylinder head. The electronically controlled throttle includes a throttle valve (63) provided in the intake passage and an actuator (65) that opens and closes the throttle valve, and in a side view, an upper edge (73) of the actuator is along a lower edge (71) of the suspension bracket, and a rear edge (74) of the actuator is along front edges (72) of the body frames.