Intake Valve Timing Control for Engine Efficiency and Knock Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for controlling intake valve closing timing in internal combustion engines face challenges in balancing increased expansion ratios with the regulation of abnormal combustion, such as pre-ignition, especially at higher compression ratios, leading to inefficiencies and potential engine output issues.
Innovation Solution
A method that adjusts the intake valve closing timing to operate within two ranges: an earlier closing range for low air demand conditions and a later closing range for high air demand conditions, while also managing valve lift and intake passage pressure to optimize air charge and prevent abnormal combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the expansion ratio is increased to improve engine operating efficiency, then energy conversion efficiency is improved, but the compression ratio increases which leads to abnormal combustion such as auto-ignition or knocking
Solution Approach 1:
The patent applies dynamic control of intake valve closing timing based on operating conditions. The closing timing is retarded when high air charge is desired and advanced when abnormal combustion risk is detected, allowing the system to adapt dynamically between improving energy efficiency and preventing abnormal combustion
Solution Approach 2:
The patent changes the intake valve closing timing parameter to control the effective compression ratio. By advancing the closing timing, the effective compression ratio is reduced to prevent abnormal combustion while maintaining the geometric expansion ratio for efficient energy conversion
2Quantity of substance
If the intake valve closing timing is retarded to increase air charge amount, then the desired amount of air inducted into the cylinder is increased, but the possibility of abnormal combustion increases
Solution Approach 1:
The system dynamically adjusts the intake valve closing timing based on real-time operating conditions. When the desired air charge amount is high, the timing is retarded to maximize air induction. When abnormal combustion is detected or predicted, the timing is advanced to reduce the effective compression ratio and eliminate the harmful effect
3Productivity
If a variable valve operation system is used to control valve lift and closing timing, then air charge amount can be controlled, but it becomes difficult to balance improvement of output with regulation of abnormal combustion
Solution Approach 1:
The patent implements a feedback control system that monitors operating conditions including air charge amount, engine speed, and abnormal combustion detection. Based on this feedback, the controller adjusts the intake valve closing timing to balance output improvement with abnormal combustion prevention
Solution Approach 2:
The variable valve operation system dynamically adjusts both valve lift and closing timing based on operating conditions. The system can increase valve lift and retard closing timing to improve output when conditions are favorable, and advance closing timing to prevent abnormal combustion when risks are detected
Data Source
AI summary
A system and method of controlling an internal combustion engine are provided. The method may include closing said intake valve at a timing in a first range, which is before a maximum charge closing timing with which an amount of air inducted into said cylinder from said air intake passage would be maximized at a given engine speed, during a cylinder cycle when a desired amount of air to be inducted into said cylinder is less than or equal to a predetermined air amount at the given engine speed. The method may further include closing said intake valve at a timing in a second range, which is after said maximum charge closing timing and separated from said first range during a cylinder cycle, when a desired amount of air to be inducted into said cylinder is greater than said predetermined air amount at the given engine speed.