Pneumatic Valve Actuation Reducing Parasitic Torque in Boosted Engines
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Solution Overview
Problem
High boost pressures in internal combustion engines lead to increased friction and parasitic torque due to strong springs required to keep intake valves closed, which is not effectively addressed by existing technologies.
Innovation Solution
A pneumatically actuated valve system using a mobile piston and venting valve to control intake valve opening and closing, exploiting intake pressure without additional power sources, and utilizing a spring to maintain valve closure, with the system designed for high-pressure environments in both 4-stroke and split-cycle engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong springs are implemented to keep intake valves closed under high boost pressure, then valve closure reliability is improved, but friction and parasitic torque increase
Solution Approach 1:
The patent applies pneumatic pressure from the intake manifold to actuate the valve stem directly, replacing the need for strong mechanical springs. The pneumatic force generated by intake pressure differential acts on the valve stem to maintain closure, eliminating excessive spring friction while ensuring reliable valve sealing under high boost conditions
Solution Approach 2:
The invention substitutes the traditional mechanical spring-based valve actuation system with a pneumatic actuation system. Instead of relying on spring force to keep the valve closed, the system uses pneumatic pressure differential to actuate the valve stem, reducing mechanical friction and parasitic torque while maintaining valve closure reliability
2Reliability
If strong springs are implemented to keep intake valves closed under high boost pressure, then valve closure reliability is improved, but friction at the camshaft increases
Solution Approach 1:
The patent uses pneumatic pressure to actuate the valve stem, replacing strong mechanical springs that cause high friction at the camshaft. The pneumatic force provides the necessary holding force without the mechanical friction associated with spring-loaded systems, reducing wear and energy loss at the camshaft interface
3Object-generated harmful factors
If a pneumatically actuated valve system is implemented, then parasitic torque is reduced, but device complexity increases
Solution Approach 1:
The valve actuation system is self-regulating through the pneumatic pressure differential created by the engine's own intake pressure. The system automatically adjusts valve positioning based on the pressure differential between the intake manifold and combustion chamber, eliminating the need for external control mechanisms and reducing overall system complexity despite the pneumatic actuation approach
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
The solution reduces parasitic torque and maintains efficient valve operation under high boost pressures by leveraging intake pressure, eliminating the need for additional power sources and minimizing friction, while ensuring reliable valve closure and opening dynamics.
Implementation Method 1
A spring is arranged in the first chamber to force the valve into close position
Implementation Method 2
The first chamber is directly connected to the intake manifold through a throttled pressurization channel
Data Source
Figure 1
Figure 2
AI summary
Boosted internal combustion engine (IC) provided with valve actuation system (VA), the combustion engine comprising a head (H) where a poppet valve (V) is arranged in such a way to open protruding in the combustion chamber and to close against a corresponding seat, the valve communicating the combustion chamber with an intake manifold (IK), the actuation system (VA) including a pneumatic actuator (PD) comprising a piston (AP) operatively connected with the stem (VS) of the poppet valve (V), at least a first chamber (FC) where the piston (AP) is movable in such a way the first chamber is between the poppet valve and the piston (AP), a spring (SP) arranged to expand the first chamber, wherein the first chamber is fluidly connected with the intake manifold through a pressurization throttled channel (PC) and a pressure sink (SK), which is at a pressure constantly under the intake one, through a controllable valve (SV).