CVVT Locking Pin Mechanism for Engine Startup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
CVVT apparatuses struggle to maintain optimal valve timing during engine startup and idling, leading to faulty starting and poor combustion due to lack of hydraulic pressure, resulting in inefficient fuel consumption.
Innovation Solution
A CVVT apparatus design that includes a locking pin, elastic member, valve bolt with a release passage, and an actuator to fix the intake valve timing of a typical Otto-cycle engine without working oil pressure, utilizing an oil control valve and electronic actuator to manage hydraulic pressures and stabilize engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the CVVT apparatus is operated by hydraulic pressure produced using the power of the engine, then the valve timing can be actively adjusted to improve fuel efficiency, but the CVVT apparatus cannot be controlled when the engine is started due to lack of hydraulic pressure
Solution Approach 1:
The locking pin is pre-positioned to engage with the rotor at a specific angular position before engine startup. This preliminary mechanical locking ensures the camshaft is held at a predetermined phase position during startup and idling, before hydraulic pressure becomes available for active CVVT control.
Solution Approach 2:
The locking pin acts as an intermediary mechanical device that transfers the predetermined phase position from the housing to the rotor/camshaft assembly. This mechanical intermediary ensures reliable phase positioning without requiring hydraulic pressure during startup conditions.
2Device complexity
If the CVVT apparatus is maintained in the most delayed state by resistance to driving of the intake camshaft in the default state, then the structure is simple without active control, but there is a lack of compression pressure resulting in faulty starting and poor combustion during idling
Solution Approach 1:
The locking pin is pre-positioned to engage with the rotor at a specific angular position that corresponds to optimal intake valve timing for startup and idling conditions. This preliminary mechanical locking ensures the camshaft is held at a predetermined phase position before engine startup, preventing the default delayed state that causes compression pressure loss.
Solution Approach 2:
The elastic member automatically pushes the locking pin into engagement with the rotor at the predetermined phase position without requiring external control systems. This self-service mechanism ensures proper valve timing is established automatically during startup and idling conditions.
3Reliability
If the locking pin is pushed by elastic force to move linearly and pass through a relatively rotating surface between the housing and the rotor, then the valve timing can be fixed without working oil pressure, but the structure becomes more complex
Solution Approach 1:
The locking function is extracted from the hydraulic control system and implemented as a separate mechanical locking pin mechanism. This extracted mechanical subsystem provides reliable phase positioning without depending on hydraulic pressure, while being relatively simple in its own right.
Solution Approach 2:
The elastic member provides the necessary force to push the locking pin linearly through the rotating surface, using elastic potential energy instead of hydraulic pressure. This alternative energy source enables the locking mechanism to function reliably during startup and idling conditions when hydraulic pressure is unavailable.
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
Enables smooth and stable engine operation during startup and idling by maintaining optimal valve timing, minimizing structural changes to the engine and improving fuel efficiency.
Implementation Method 1
a locking pin configured to restrict rotation of the rotor relative to the housing when pushed by an elastic force to move linearly
Implementation Method 2
a release passage through which a release pressure provided through the camshaft is transferred to the locking pin via the rotor
Data Source
AI summary
A continuous variable valve timing apparatus for an engine includes: a housing, a rotor installed to be rotatable relative to the housing and connected to a camshaft, a locking pin configured to restrict rotation of the rotor relative to the housing when pushed by an elastic force to move linearly and pass through a relatively rotating surface between the housing and the rotor, an elastic member installed to provide the elastic force, a valve bolt coupled to the camshaft through the housing and the rotor, wherein the valve bolt includes a release passage through which a release pressure provided through the camshaft is transferred to the locking pin via the rotor, and a valve means for selectively blocking or unblocking the release passage, and an actuator installed to actuate the valve means of the valve bolt according to an actuation displacement.