Valve Timing Control for Hybrid Engine Start
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Solution Overview
Problem
Current valve open/close timing control systems for internal combustion engines in hybrid vehicles inefficiently consume power when starting the engine, especially when the compression ratio is reduced to suppress engine vibrations, leading to increased battery power usage and reduced startability.
Innovation Solution
A valve open/close timing control system that includes a drive-side and driven-side rotating member with a relative rotational phase control mechanism, using advanced and retarded angle chambers and locking mechanisms to adjust the phase for efficient engine starting, allowing the engine to be started by either the starter motor or traveling motor, optimizing power usage and vibration suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the compression ratio is reduced to suppress engine vibrations, then vibration suppression is improved, but startability deteriorates and battery power consumption increases
Solution Approach 1:
The valve open/close timing control device dynamically adjusts the relative rotational phase between the drive-side rotating member (connected to crankshaft) and driven-side rotating member (connected to camshaft) based on operating conditions. During engine starting, the system can set the phase to a most retarded angle position to maintain high compression ratio for reliable starting, then transition to intermediate or advanced angles during operation to suppress vibrations and improve fuel efficiency.
Solution Approach 2:
The system changes the compression ratio parameter by adjusting valve timing phase positions. By providing multiple discrete phase positions (most retarded angle, intermediate angles, most advanced angle), the system can select the appropriate compression ratio for each operating condition - high compression for starting, reduced compression for vibration suppression during operation.
2Object-affected harmful factors
If the engine is started by the traveling motor at reduced compression ratio, then vibration suppression is improved, but battery power consumption increases and travel distance decreases
Solution Approach 1:
The system dynamically switches between different starting modes based on battery state of charge and operating conditions. When battery charge is sufficient, the system can use the traveling motor to start the engine at reduced compression ratio for vibration suppression. When battery charge is low, the system uses the starter motor with high compression ratio to conserve battery power, thereby extending travel distance.
Solution Approach 2:
The system changes the compression ratio parameter during engine starting by adjusting valve timing phase. By maintaining high compression ratio during starter motor starting, the system ensures reliable ignition and reduces the need for high cranking speeds, thereby reducing battery power consumption and extending travel distance.
3Reliability
If the engine is started at high rotational speed to ensure ignition, then startability is improved, but power consumption increases
Solution Approach 1:
The system changes the compression ratio parameter by adjusting valve timing phase to a most retarded angle position during engine starting. This increases the compression ratio, which improves ignition reliability and allows the engine to start at lower cranking speeds, thereby reducing power consumption from the battery and starter motor.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces power consumption during engine start by using the starter motor at a higher compression ratio phase and the traveling motor at a phase that suppresses vibrations, enhancing startability and extending travel distance on a single battery charge.
Implementation Method 1
a first locking member which is biased to a locking position by a first biasing mechanism for restraining the relative rotational phase at a predetermine first locking phase
Implementation Method 2
a second locking member which is biased to a locking position by a second biasing mechanism for restraining the relative rotational phase at a second locking phase which is displaced in the retarded angle direction from the first locking phase
Data Source
AI summary
Provided is a valve open/close timing control system where a valve open/close timing control device includes a drive-side rotating member, a driven-side rotating member, a relative rotational phase control mechanism, and a first locking member, in which the internal combustion engine is configured to be started by a drive force generated by a traveling motor or by a drive force generated by a starter motor, and the valve open/close timing control system also includes a control unit which is configured, for starting the internal combustion engine while changing the relative rotational phase at the time of starting the internal combustion engine, to drive the starter motor or the traveling motor at the time of starting the internal combustion engine at the first locking phase, and to drive the traveling motor at the time of starting the internal combustion engine at the second locking phase.