Engine Starting System Throttle Control for Vibration
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Solution Overview
Problem
Existing engine starting systems face challenges in balancing restartability and vibration reduction, as increasing the throttle opening degree to enhance restartability leads to stronger vibrations, while decreasing it to reduce vibrations undermines restartability.
Innovation Solution
An engine starting system that adjusts the throttle opening degree based on vehicle speed and transmission input rotational speed using an electronic control unit to optimize scavenging and ignition-based engine starting, determining whether to use ignition-based starting or a starting device for reliable restarts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the throttle opening degree is increased to enhance restartability, then the restartability is improved, but the vibrations become stronger
Solution Approach 1:
The throttle opening degree is dynamically adjusted based on vehicle speed and transmission input rotational speed. The ECU determines the throttle opening degree from a map that varies with these parameters, allowing the system to optimize between restartability and vibration reduction in real-time rather than using a fixed opening degree
Solution Approach 2:
The system changes the throttle opening degree parameter according to operating conditions (vehicle speed and transmission input rotational speed). By varying this parameter within specific ranges based on current vehicle state, the system achieves both adequate scavenging for restartability and acceptable vibration levels
2Object-affected harmful factors
If the throttle opening degree is decreased to reduce vibrations, then the vibrations are reduced, but the restartability deteriorates
Solution Approach 1:
The system dynamically determines the throttle opening degree based on real-time vehicle speed and transmission input rotational speed measurements. This dynamic adjustment ensures that the throttle opening is sufficient for scavenging when needed while limiting vibrations when vehicle speed provides natural damping
Solution Approach 2:
The throttle opening degree parameter is adjusted according to operating conditions stored in a map. The ECU selects appropriate opening degree ranges based on vehicle speed and transmission input rotational speed, optimizing the balance between scavenging effectiveness and vibration reduction for each operating scenario
Data Source
AI summary
An engine starting system includes an electronic control unit configured to: automatically stop an engine in response to an engine stop request, and restart the engine in response to an engine restart request; calculate, in the course of automatically stopping the engine, a throttle opening degree based on at least one of a vehicle speed or an input rotational speed of a transmission, such that the throttle opening degree when the at least one of the vehicle speed or the input rotational speed is high is larger than the throttle opening degree when the at least one of the vehicle speed or the input rotational speed is low; carry out scavenging of each cylinder by opening a throttle valve to the calculated throttle opening degree in the course of automatically stopping the engine; and restart the engine through ignition-based engine starting in response to the engine restart request.