Variable-Compression Crankshaft With Fluidic Connecting Rod Control
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Solution Overview
Problem
Existing methods for controlling the length of a connecting rod in a variable compression ratio engine face challenges such as complex and expensive manufacturing, significant acoustic emissions, rapid wear, high inertia, and sensitivity to engine speed due to mechanical shock piloting and hydraulic systems.
Innovation Solution
A crankshaft with a fluidic control circuit that allows continuous contact with the connecting rod adjustment system actuator, independent of angular position, using a fluidic piloting system that reduces inertia and allows pressure oscillation, enabling control without lubrication circuit interference and using gases to mitigate rotation effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical shock piloting is used to control connecting rod length, then the control response is fast, but the manufacturing complexity and cost increase significantly due to extremely precise positioning requirements
Solution Approach 1:
The patent replaces the mechanical shock piloting system with a magnetic field-based control system. The permanent magnet mounted on the control element interacts with a sensor (such as a Hall effect sensor or magnetoresistive sensor) to detect the angular position and control the connecting rod length adjustment, eliminating the need for mechanical clashing and extremely precise mechanical positioning.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the control element and the sensing system. The permanent magnet generates a magnetic field that varies with the angular position of the control element, and this magnetic field is detected by the sensor to determine the position and control the adjustment, serving as a non-contact intermediary that avoids mechanical wear and positioning issues.
2Measurement precision
If mechanical shock piloting is used to control connecting rod length, then the control is precise, but acoustic emissions increase significantly and wear occurs rapidly
Solution Approach 1:
The patent replaces the mechanical contact-based control system with a non-contact magnetic field sensing system. The permanent magnet and sensor combination allows for precise detection of the control element's angular position without physical contact, thereby eliminating acoustic emissions from mechanical clashing and preventing wear of contacting parts.
Solution Approach 2:
The patent converts the potentially harmful mechanical shock and contact into a beneficial non-contact magnetic field interaction. By using the magnetic field instead of mechanical contact, the system achieves precise control while avoiding the harmful effects of acoustic emissions and wear associated with mechanical shock piloting.
3Ease of operation
If hydraulic control system is used to adjust connecting rod length, then the control is smooth without shock, but the inertia to control increases due to the large volume of lubrication circuit
Solution Approach 1:
The patent replaces the hydraulic control system with a magnetic field-based control system. The permanent magnet and sensor combination provides smooth control through non-contact detection of the control element's position, eliminating the need for hydraulic fluid and the associated large volume and inertia, while maintaining smooth operation without shock.
4Device complexity
If common lubrication circuit is used for hydraulic control, then the system is simple, but selective cylinder-to-cylinder control becomes impossible
Solution Approach 1:
The patent segments the control system by providing individual control elements with permanent magnets and sensors for each cylinder or connecting rod. This segmentation allows each cylinder to be controlled independently and selectively, while the overall system structure remains relatively simple compared to a complex hydraulic distribution system.
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
This solution reduces control inertia, avoids mechanical shock, and allows for precise control of connecting rod length adjustment, reducing wear and acoustic emissions while being less sensitive to engine speed, enabling efficient and stable operation.
Implementation Method 1
using a fluidic piloting system that reduces inertia and allows pressure oscillation
Implementation Method 2
it makes it possible to work with a fluid other than oil, for example a gas, which makes it possible to overcome the effects of inertia linked to the speed of rotation of the crankshaft
Data Source
Figure 1~2
Figure 3~4a
Figure 4b~4c
AI summary
The invention relates to a crankshaft (100) for controlled variable compression ratio engine, having an axis of rotation defining a longitudinal axis and comprising at least one crank pin (2), at least one journal (3) connected by a connecting web (4), and at least one control element (50) able to move translationally along the longitudinal axis (y) in order to collaborate with an actuator of a system for adjusting the length of a connecting rod. The crankshaft (100) is notable in that: • the control element (50), positioned in the region of the connecting web (4), comprises an annular part (51) coaxial with the crank pin (2) and able to establish continuous contact with the actuator of the system for adjusting the length of the connecting rod, regardless of the angular position of the crankshaft (100), • the crankshaft (100) comprises a fluidic control circuit for moving the control element (50) along the longitudinal axis (y).