Crossed Hydraulic Intake Valve Circuits for Independent Cylinder Control
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Solution Overview
Problem
Existing internal-combustion engines with variable intake valve actuation systems lack the ability to control the two intake valves of each cylinder independently, limiting optimization of air flow and combustion efficiency, particularly in diesel and controlled-ignition engines.
Innovation Solution
The system rearranges hydraulic circuits to associate each intake valve with different cams, allowing independent control of the two intake valves of each cylinder, using either two-way, two-position or three-way, three-position solenoid valves to manage the hydraulic actuators, enabling differential control and sequential opening and closing of the valves based on engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single hydraulic circuit controls both intake valves of each cylinder, then the device complexity is reduced, but the ability to independently control valve timing and optimize air charge distribution is lost
Solution Approach 1:
The hydraulic control system is segmented into separate circuits: one circuit (first hydraulic circuit) controls the first intake valve of each cylinder, while another circuit (second hydraulic circuit) controls the second intake valve of each cylinder. This segmentation enables independent timing control of each valve, resolving the contradiction between system simplicity and control flexibility.
2Productivity
If both intake valves open simultaneously during the intake stage, then the structure is simple, but air charge distribution optimization and emission reduction are limited
Solution Approach 1:
The system implements periodic, staggered valve operation where the first intake valve opens during a first time interval and closes before the second intake valve opens. The second intake valve then opens during a second time interval. This periodic sequencing optimizes air charge distribution and reduces emissions by creating controlled turbulence and improving combustion efficiency.
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 configuration enhances combustion efficiency by optimizing air flow patterns, reducing dissipative losses, and improving pollutant emission reduction, particularly at partial engine loads and idling conditions.
Implementation Method 1
a pumping piston, which is driven by the tappet associated to the respective engine cylinder and is configured for transferring pressurized-fluid, through a pressure chamber, towards two hydraulic actuators associated to respective intake valves of the engine
Implementation Method 2
an electrically actuated control valve able to set said pressurized-fluid chamber in communication with a low-pressure exhaust channel, which communicates with a pressurized-fluid accumulator, in such a way that, when said control valve is opened, pressurized fluid is discharged from the pressure chamber into said low-pressure channel and the intake valves controlled by said hydraulic circuit close due to the action of the respective return springs
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An internal-combustion engine has a plurality of cylinders each provided with two intake valves (V1, V2) that are driven by respective pumping pistons (16) operatively associated to the cams (CAM 1, CAM 2, CAM 3, CAM 4) of a camshaft (11), by means of respective hydraulic circuits. The hydraulic circuit associated to each pumping piston (16) and to the respective cam (CAM 1, CAM 2, CAM 3, CAM 4) has its pressure chamber (C) communicating with hydraulic actuators (21) of two intake valves (V1, V2) associated to two different cylinders (CYL 1, CYL 2, CYL 3, CYL 4) of the engine, so that the two intake valves (V1, V2) of each cylinder (CYL 1, CYL 2, CYL 3, CYL 4) are controlled, via two different hydraulic circuits, by cams associated to two different cylinders. Each cam (CAM 1, CAM 2, CAM 3, CAM 4) is configured in such a way as to give rise to a cycle of opening and closing of each of the intake valves of the engine in an angular range of rotation of the crankshaft considerably less than 180° in such a way that, in each operating cycle of a cylinder, only one first intake valve (V1) initially opens and closes while the second intake valve (V2) remains closed, and then the second intake valve (V2) opens and closes while the first intake valve (V1) remains closed.