Camshaft Driven Pump for Hydraulic Phaser Activation
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Solution Overview
Problem
Existing variable camshaft timing mechanisms face delays in altering the relative timing between the camshaft and crankshaft at engine startup due to lack of engine oil pressure, which hinders immediate phaser operation.
Innovation Solution
A camshaft driven pump is integrated within the camshaft to provide a high-pressure fluid burst to the phaser, ensuring immediate phaser activation at startup and during low engine oil pressure conditions, utilizing a piston assembly and check valves to manage pressure and flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional oil pressure actuated VCT systems are used, then the system structure is simple, but the phaser cannot be activated immediately at engine startup due to lack of engine oil pressure
Solution Approach 1:
The camshaft driven pump is activated immediately at engine startup to deliver a high-pressure fluid burst to the phaser before the main engine oil pressure is available. This preliminary action of providing fluid pressure in advance eliminates the startup delay that would otherwise occur while waiting for engine oil pressure to build up.
Solution Approach 2:
The camshaft driven pump acts as an intermediary mechanism that bridges the gap between engine startup and the availability of main engine oil pressure. It provides the necessary fluid pressure to the phaser during the transition period when the engine oil pressure is insufficient, enabling immediate phaser activation without waiting for the main oil system to pressurize.
2Speed
If a camshaft driven pump is integrated to provide immediate high-pressure fluid, then the phaser activation speed is improved, but the device complexity increases
Solution Approach 1:
The pump mechanism is integrated directly into the camshaft structure, merging the pump function with the existing camshaft component. This combination eliminates the need for a separate pump assembly and reduces overall system complexity while still providing the necessary high-pressure fluid delivery for immediate phaser activation.
Solution Approach 2:
The camshaft driven pump utilizes the camshaft's own rotational motion to drive the pump mechanism, eliminating the need for an external power source or additional actuation system. The pump serves itself by being directly coupled to the camshaft, converting the camshaft's mechanical energy directly into fluid pressure without requiring separate motors or actuators.
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 instant phaser activation at engine startup and enhances phaser operation during low engine oil conditions, ensuring timely and efficient adjustment of camshaft and crankshaft timing.
Implementation Method 1
a positive displacement pump within the camshaft which is driven by a pin to compress and trigger fluid to be dispensed to the phaser
Implementation Method 2
utilizing a piston assembly and check valves to manage pressure and flow
Data Source
AI summary
A mechanism provides high pressure fluid to a cam phaser on demand. The mechanism includes a positive displacement pump within the camshaft which is driven by a pin to compress and trigger fluid to be dispensed to the phaser.