Valve Timing Phase Control for Catalyst Protection and Fast Restarts
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Solution Overview
Problem
Existing valve opening and closing timing control devices in hybrid vehicles experience response delays and deteriorated drivability when shifting from a retard to an advance valve opening timing during engine restarts, leading to potential catalyst deterioration and excessive fuel supply.
Innovation Solution
A valve opening and closing timing control device that includes a driving-side and driven-side rotating body with a phase adjusting mechanism controlled by an electric motor, allowing for retard and advance operations to set the relative rotation phase, ensuring optimal valve timing adjustments during engine stops and restarts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve opening timing is shifted to the retard side during engine stop, then catalyst deterioration is prevented and fuel supply is controlled, but response delay occurs during engine restart and drivability deteriorates
Solution Approach 1:
The control device performs preliminary action by shifting the valve opening timing to the advance side before the engine restart is actually requested. Specifically, when the engine rotational speed reaches a predetermined lower limit during stopping, the control device starts shifting the timing from retard position toward advance position in advance of the restart request, so that the timing is already optimized for restart when needed, eliminating response delay while maintaining catalyst protection during the stop period
2Object-affected harmful factors
If the valve opening timing remains in the retard phase during engine stop, then fresh air supply to catalyst is reduced, but engine restart requires timing advancement causing response delay
Solution Approach 1:
The control device applies dynamics by continuously and dynamically adjusting the valve opening timing based on real-time engine rotational speed and operating conditions. Instead of maintaining a fixed retard position, the timing is dynamically shifted toward advance position as the engine approaches restart conditions, allowing the system to adapt optimally between catalyst protection mode during stop and restart readiness mode, eliminating the trade-off between these two requirements
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
Enhances drivability and reduces catalyst deterioration by minimizing fresh air supply during engine stops, while maintaining low fuel consumption and rapid engine response.
Implementation Method 1
a phase adjusting mechanism configured to set a relative rotation phase between the driving-side rotating body and the driven-side rotating body by a driving force of an electric motor
Data Source
AI summary
A valve open/close timing controller including a driving-side rotating body rotating about a rotating shaft core synchronously with a crankshaft of an internal combustion engine with a driven-side rotating body inside the driving-side rotating body and coaxially with the rotating shaft core that rotates integrally with a camshaft to open/close an intake valve of an internal combustion engine. A phase adjusting mechanism sets a relative rotation phase between the driving-side and driven-side and a phase controller performs a retard operation to shift the relative rotation phase to a most retarded phase by displacing the driven-side rotating body in a direction opposite to the driving-side rotating body, and, when rotational speed of the engine reaches a lower limit rotational speed during stopping of the engine, advances the relative rotation phase as the most retarded phase by displacing the driven-side rotating body in a same direction as the driving-side rotating body.