Intake Air Control Valve Opening Adjustment for Engine Speed Stability
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Solution Overview
Problem
Existing control systems for internal combustion engines face challenges in managing intake air flow rate during transitions from partial-cylinder to all-cylinder operation, leading to excessive engine rotational speed and prolonged return to target speed due to delayed intake pressure adjustments.
Innovation Solution
A control system that includes an intake air control valve with switching and correcting mechanisms to adjust the intake air flow rate by switching the basic opening of the valve from one setting to another and gradually correcting it in the closing direction during a predetermined time period when increasing the number of operating cylinders, accompanied by ignition timing control to maintain target rotational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the throttle valve opening is changed stepwise when switching from partial-cylinder to all-cylinder operation, then the intake air flow rate control responds quickly to the cylinder number change, but the intake pressure downstream of the throttle valve does not immediately change, causing the engine rotational speed to greatly exceed the target speed and take a long time to return
Solution Approach 1:
The patent applies preliminary action by predicting the delay in intake pressure response and pre-adjusting the throttle valve opening accordingly. When switching from partial-cylinder to all-cylinder operation, the control system calculates a corrected throttle opening that accounts for the expected pressure lag, preventing excessive engine speed increase before it occurs. This proactive adjustment resolves the contradiction by preparing the system in advance for the delayed pressure response.
2Reliability
If a predetermined time period delay is introduced to match the intake air flow rate change timing with the operating cylinder number change, then the engine rotational speed fluctuation is reduced, but the response time of the intake air flow rate control is increased
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the throttle valve opening based on the operating cylinder number and the predicted intake pressure state. Instead of using a fixed time delay, the control system modifies the throttle opening parameter in real-time according to the current operational state, allowing for rapid response while maintaining rotational speed stability. This resolves the contradiction by changing the control parameter adaptively rather than using a fixed temporal delay.
Data Source
AI summary
A control system for an internal combustion engine having a plurality of cylinders and a cylinder halting mechanism for halting operation of at least one of the plurality of cylinders by stopping operation of at lease one intake valve of the at least one cylinder. The control system includes an intake air control valve for controlling an amount of air supplied to the engine. An opening of the intake air control valve is changed when performing an increase in a number of operating cylinders in an idling condition of the engine. A basic opening of the intake air control valve is switched from a first basic opening corresponding to the number of operating cylinders before the increase in the number of operating cylinders to a second basic opening corresponding to the number of operating cylinders after the increase in the number of the operating cylinders. The basic opening is corrected in the closing direction during a predetermined time period when increasing the number of operating cylinders.