Valve Actuation System with Lost Motion Mechanisms for Cylinder Deactivation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing valve actuation systems face challenges in combining cylinder deactivation and early exhaust valve opening (EEVO) operations, leading to reduced air mass flow and inefficient exhaust system energy, as well as rocker arm biasing issues due to differing speed ranges and stress requirements.
Innovation Solution
A valve actuation system incorporating a lost motion subtracting mechanism in the pre-rocker arm valve train and a lost motion adding mechanism in the valve bridge, configured to convey or lose valve actuation motions based on operating states, with an engine controller managing these mechanisms to achieve desired modes of operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single valve actuation system is used for both cylinder deactivation and EEVO operations, then system complexity is reduced, but rocker arm biasing control becomes insufficient due to differing speed ranges and stress requirements
Solution Approach 1:
The valve actuation system is segmented into two separate mechanisms: a lost motion subtracting mechanism in the pre-rocker arm valve train and a lost motion adding mechanism in the valve bridge. This segmentation allows each mechanism to be optimized for specific operating modes (cylinder deactivation and EEVO operations) without compromising the other, thereby maintaining reliability while managing system complexity through functional division.
2Use of energy by moving object
If cylinder deactivation is implemented to improve fuel efficiency, then fuel consumption is reduced, but air mass flow through the engine is reduced
Solution Approach 1:
The system dynamically switches between different operational modes using the lost motion mechanisms. The lost motion subtracting mechanism enables cylinder deactivation for fuel efficiency improvement, while the lost motion adding mechanism enables EEVO operations to restore air mass flow when needed. This dynamic capability allows the system to optimize fuel efficiency during steady-state operation while maintaining adequate air flow during transient conditions.
3Use of energy by moving object
If lost motion mechanisms are deployed to enable both cylinder deactivation and EEVO operations, then fuel efficiency and emissions control are improved, but device complexity increases
Solution Approach 1:
Both the lost motion subtracting mechanism and the lost motion adding mechanism are integrated into the existing valve actuation system architecture, allowing a single system to perform multiple functions: cylinder deactivation, EEVO operations, and normal valve actuation. This multi-functionality approach enables the system to achieve fuel efficiency and emissions control improvements without requiring entirely separate mechanisms for each operation, thereby limiting the increase in device complexity.
Data Source
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 a pre-rocker arm valve train component 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 is arranged in a valve bridge and 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.