Intake Valve Control for Engine Reacceleration Interference
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Solution Overview
Problem
Existing intake air control systems for internal combustion engines face challenges in controlling intake air quantity during transient periods between low-load and reacceleration conditions, leading to potential interference between the intake valve and piston due to differing response speeds of valve lift and phase angle mechanisms.
Innovation Solution
A controller adjusts the target values for valve lift and phase angle to maintain a minimum clearance above a permissible value, switching to a second target value when interference is predicted, ensuring equivalent engine torque and preventing physical interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the valve lift and phase angle are varied to control intake air quantity during transient periods, then the reacceleration performance is improved, but the minimum clearance between the intake valve and piston may become less than the permissible value causing physical interference
Solution Approach 1:
The controller predicts the future state of valve lift and phase angle based on current acceleration conditions, and in advance determines whether the minimum clearance will fall below the permissible value. This preliminary assessment allows the system to prepare appropriate corrective actions before actual interference occurs, resolving the contradiction by preventing the harmful effect while maintaining performance improvement goals.
Solution Approach 2:
The controller continuously monitors the actual valve lift and phase angle, compares them with target values, and adjusts the control signals accordingly. This feedback mechanism ensures that when the predicted clearance approaches the permissible limit, the controller can modify the valve control to maintain adequate clearance, thus preventing interference while preserving reacceleration performance.
2Power
If the valve phase angle is advanced to increase intake air quantity, then the engine torque is improved, but the risk of physical interference between the intake valve and piston increases
Solution Approach 1:
The controller applies preliminary anti-action by predicting the valve phase angle and lift that would result from acceleration conditions, assessing whether these predicted values would cause the minimum clearance to drop below permissible levels, and in advance determining corrective control signals to prevent interference before it occurs.
Solution Approach 2:
The controller dynamically adjusts the target valve phase angle and lift parameters based on predicted clearance conditions. When advancement of the phase angle would cause harmful interference, the controller modifies these parameters to maintain adequate clearance, thus eliminating the harmful effect while preserving beneficial torque production.
3Speed
If the variable valve operating mechanism responds quickly to change valve lift and phase angle, then the control responsiveness is improved, but the difference in response speeds between valve lift and phase angle mechanisms may cause interference
Solution Approach 1:
The controller performs preliminary assessment of the future valve state based on current acceleration conditions and predicted response characteristics of the valve mechanisms. This advance prediction allows the controller to identify potential clearance issues before they manifest, enabling proactive adjustment of control targets to maintain adequate clearance despite differential response speeds.
Solution Approach 2:
The controller continuously monitors actual valve lift and phase angle positions, compares them with target values, and adjusts control signals in real-time. This feedback mechanism compensates for differences in response speeds between the valve lift and phase angle mechanisms, ensuring coordinated operation that maintains adequate clearance while preserving control responsiveness.
Data Source
AI summary
An apparatus is provided for controlling an intake valve of a vehicular internal combustion engine. The apparatus includes a variable valve operating mechanism configured to vary a valve lift and a valve phase angle of the intake valve, and a controller. The controller calculates a desired first target value at a current engine operating condition, a reacceleration estimated value based on an engine rotational speed and estimated operating load upon reacceleration, and a second target value at which engine torque is equivalent to engine torque at the first target value. The controller sets the first target value as a control target value, and then switches the control target value to the second target value when a minimum clearance between the intake valve and a piston is determined to become less than a permissible value during variation of the intake valve from the first target value toward the reacceleration estimated value.