In-Series Lost Motion Valve Actuation for Cylinder Deactivation and EEVO
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Solution Overview
Problem
Existing valve actuation systems for internal combustion engines face challenges in combining cylinder deactivation and early exhaust valve opening (EEVO) operations, leading to reduced air mass flow, increased stress on components, and inadequate rocker arm control due to differing speed ranges and valve actuation requirements.
Innovation Solution
A valve actuation system incorporating a lost motion subtracting mechanism and a lost motion adding mechanism in series, controlled by an engine controller, to manage main and auxiliary valve actuations, ensuring efficient operation across different modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single lost motion mechanism is used for both cylinder deactivation and auxiliary valve actuation, then device complexity is reduced, but the mechanism cannot simultaneously handle different valve actuation requirements and speed ranges
Solution Approach 1:
The valve actuation system is divided into two separate lost motion mechanisms: a first lost motion mechanism for cylinder deactivation and a second lost motion mechanism for auxiliary valve actuation. Each mechanism is independently controlled and optimized for its specific function, allowing the system to handle different valve actuation requirements and speed ranges effectively.
2Use of energy by moving object
If cylinder deactivation is implemented, then fuel economy improves, but air mass flow through the engine is reduced
Solution Approach 1:
The system dynamically switches between different operational modes (cylinder deactivation, auxiliary valve actuation, or both) based on engine conditions. The separate control mechanisms allow independent adjustment of each function, enabling the system to optimize fuel economy during cylinder deactivation while maintaining adequate air mass flow through auxiliary valve actuation when needed.
3Temperature
If early exhaust valve opening is implemented, then exhaust temperature increases for fast warmup, but additional valve actuation motions increase stress on components
Solution Approach 1:
The valve actuation motions are segmented into separate controlled mechanisms. The second lost motion mechanism specifically handles auxiliary valve actuation including early exhaust valve opening, isolating these additional motions from the main valve actuation system. This segmentation prevents stress concentration on single components while enabling exhaust temperature control for fast warmup.
4Adaptability or versatility
If separate control mechanisms are used for different valve actuation modes, then adaptability improves, but device complexity increases
Solution Approach 1:
Each lost motion mechanism is designed with multi-functionality to handle various valve actuation modes. The first mechanism handles both main valve actuation and cylinder deactivation, while the second mechanism handles auxiliary valve actuation including early exhaust opening and late intake closing. This universal design reduces the need for entirely separate control systems for each function.
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 system effectively manages both cylinder deactivation and EEVO operations, maintaining optimal air flow and reducing component stress, while providing efficient rocker arm control across varying engine speeds.
Implementation Method 1
an outer plunger spring (146) biased in opposition to one another
Implementation Method 2
an inner piston spring (144) biases the inner plunger (160) into position
Implementation Method 3
provision of sufficiently pressurized hydraulic fluid to the top of the inner plunger (160) causes the inner plunger (160) to slide downward
Data Source
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AI summary
A valve actuation system comprises a valve actuation motion source configured to provide a main valve actuation motion and an auxiliary valve actuation motion for actuating at least one engine valve via a valve actuation load path. A lost motion subtracting mechanism is arranged in the valve actuation load path and configured, in a first default operating state, to convey at least the main valve actuation motion and configured, in a first activated state, to lose the main valve actuation motion and the auxiliary valve actuation motion. Additionally, a lost motion adding mechanism configured, in a second default operating state, to lose the auxiliary valve actuation motion and configured, in a second activated state, to convey the auxiliary valve actuation motion, wherein the lost motion adding mechanism is in series with the lost motion subtracting mechanism in the valve actuation load path at least during the second activated state.