Throttle Valve Controller with Dynamic Lower Limit for Overshoot Prevention
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Solution Overview
Problem
Throttle valves in internal combustion engines may overshoot and collide with the full close position during high-speed closure, causing damage and deformation, especially in fuel efficiency-critical vehicles like HEVs and CVT-employed ones, where precise control of engine power and air demand is required.
Innovation Solution
A throttle valve controller that determines a second lower limit smaller than the first lower limit based on the vehicle's operating state and engine speed to prevent overshoot, allowing for wider engine power control and improved fuel efficiency without costly modifications, by using a motor-driven throttle valve with software-defined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the throttle valve is closed at high speed to reduce air demand and improve fuel efficiency, then fuel efficiency is improved, but the throttle valve may overshoot and collide with the full close position causing damage
Solution Approach 1:
The control device determines a second lower limit for the throttle valve opening before the valve reaches the full close position. This preliminary action prevents overshoot by establishing a safety margin in advance, allowing the valve to be closed at high speed for fuel efficiency while avoiding collision with the mechanical full close position
Solution Approach 2:
The control device dynamically changes the lower limit parameter of the throttle valve opening based on engine operating conditions. When engine speed is below a predetermined threshold or other conditions indicate low collision risk, the second lower limit is applied to minimize opening and maximize fuel efficiency. When conditions change, the first lower limit is applied to prevent overshoot
2Reliability
If a higher closing limiter is set to prevent overshoot and damage, then throttle valve reliability is improved, but fuel efficiency deteriorates due to increased air demand
Solution Approach 1:
The control device dynamically adjusts the closing limiter based on real-time engine operating conditions. The limiter is not fixed but varies according to engine speed, throttle position, and other parameters. This dynamic adjustment allows the system to optimize between safety and fuel efficiency for each operating point
Solution Approach 2:
The control device changes the limiter parameter based on engine operating conditions. When engine speed is below a predetermined threshold or the throttle valve is approaching the full close position under safe conditions, the second lower limit is applied to minimize air demand and improve fuel efficiency. When conditions indicate potential overshoot risk, the first lower limit is applied to prevent damage
3Loss of energy
If the throttle valve opening is minimized to improve fuel efficiency, then air demand is reduced, but the risk of collision with the full close position increases
Solution Approach 1:
The control device determines a second lower limit before the throttle valve reaches the full close position. This preliminary establishment of a safety margin prevents collision by ensuring the valve stops before the mechanical full close position, even when minimizing opening for fuel efficiency
Solution Approach 2:
The control device continuously monitors the throttle valve position and engine operating conditions, adjusting the lower limit dynamically based on feedback. When the valve approaches the full close position or engine conditions change, the system adjusts the limiter to prevent overshoot while maintaining minimal opening for fuel efficiency
Data Source
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AI summary
If a throttle valve (40) is moved toward the mechanical full close position at high speed, the throttle valve (40) may overshoot and collide against the full close position. This may damage and deform the throttle valve (40). It is an object of the present invention to set a lower limiter to the throttle valve (40) so as to secure a margin to prevent such collision while attaining lowered fuel consumption or improved fuel efficiency. The above-mentioned object is attained by a throttle valve controller for an internal combustion engine (65), which comprises: a throttle valve (40) which is driven by a motor; means for determining the target opening of the throttle valve (40) based on the operating state of the vehicle or internal combustion engine (65); a first lower limit which is determined beforehand as the minimum target opening; and means for setting a second lower limit which is smaller than the first lower limit if the determined target opening is smaller than a predetermined opening and/or if the rotation speed of the internal combustion engine (65) is lower than a predetermined speed.