Engine Control Apparatus for Torque Shock Mitigation
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Solution Overview
Problem
Existing engine control systems experience torque shock when switching from all-cylinder to reduced-cylinder operation due to delayed increase in intake air amount, leading to power output reduction and instability.
Innovation Solution
An engine control apparatus with a valve deactivation mechanism, exhaust valve timing adjustment, and intake air amount control system that increases intake air before switching to reduced-cylinder operation, and retards ignition timing to manage internal EGR gas, ensuring stable combustion and preventing torque shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intake air amount is increased before switching to reduced-cylinder operation, then the intake air shortage of activated cylinders is suppressed, but the power output of the entire engine increases which may cause torque shock
Solution Approach 1:
The patent applies preliminary action by increasing the intake air amount and adjusting ignition timing to the retard side before switching to reduced-cylinder operation. This preparatory control ensures that when cylinders are deactivated, the remaining activated cylinders already have sufficient air supply and appropriate combustion timing, preventing torque shock while maintaining reliability.
Solution Approach 2:
The patent changes operational parameters (intake air amount and ignition timing) before the switching event. By adjusting these parameters in advance and then deactivating cylinders, the system achieves smooth transition without torque shock, resolving the contradiction between maintaining power output stability and ensuring adequate air supply.
2Quantity of substance
If the throttle valve opening angle is increased before switching to reduced-cylinder operation, then the intake air amount increases, but the power output increases which may cause torque shock
Solution Approach 1:
The patent uses preliminary action by adjusting the throttle valve opening angle before cylinder deactivation. This ensures that when the switching occurs, the intake air amount is already optimized for the reduced-cylinder configuration, preventing both air shortage and unwanted power fluctuations that would cause torque shock.
Solution Approach 2:
The patent changes the throttle valve opening angle parameter in advance of the switching event. This parameter adjustment, combined with subsequent cylinder deactivation, achieves the dual goal of ensuring adequate air supply to activated cylinders while maintaining stable power output without torque shock.
3Productivity
If combustion is stopped in some cylinders immediately, then the reduced-cylinder operation starts, but the intake air amount does not instantaneously increase leading to torque shock
Solution Approach 1:
The patent applies preliminary action by preparing the intake air amount and ignition timing before stopping combustion in selected cylinders. This ensures that when the reduced-cylinder operation begins, the system is already in the correct state to maintain torque stability, achieving both productivity improvement and reliability.
Solution Approach 2:
The patent uses preliminary anti-action by counteracting the potential torque shock before it occurs. By adjusting intake air amount and ignition timing in advance, the system prevents the harmful effect of torque shock that would otherwise result from immediate cylinder deactivation without proper preparation.
Data Source
AI summary
In response to a switching demand from an all-cylinder operation to a reduced-cylinder operation, the amount of air to be taken into each of cylinders 2A to 2D is made larger than the amount of air during the all-cylinder operation in a normal state. Preparatory control of changing the ignition timing of ignition device to a timing on the retard side with respect to the ignition timing during the all-cylinder operation in the normal state is executed. After termination of the preparatory control, the reduced-cylinder operation is started. During execution of the preparatory control, the valve closing timing of an exhaust valve 9 is changed to a timing on the advance side with respect to the valve closing timing thereof during the all-cylinder operation in the normal state so as to reduce the amount of internal EGR gas in at least a part of an operating range C.