Engine Control Device for Torque Stabilization
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Solution Overview
Problem
Existing engine control devices fail to stabilize engine torque when switching from reduced-cylinder operation to all-cylinder operation due to incomplete air replacement in idle cylinders and misfire risks caused by residual burned gases.
Innovation Solution
A control device that adjusts valve timing and air intake to account for residual gases in idle cylinders by opening the exhaust valve before the intake valve during the transition, and sets the ignition period based on the internal EGR gas amount to stabilize engine torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the intake air amount to all cylinders is increased before stopping combustion in idle cylinders, then the intake air amount is sufficient for all cylinders, but the engine output temporarily increases causing torque shock
Solution Approach 1:
The patent applies preliminary action by increasing the intake air amount to all cylinders before stopping combustion in idle cylinders. This ensures that sufficient air is available in the cylinders before the transition to reduced-cylinder operation, preventing torque shock caused by sudden air shortage while avoiding excessive torque increase that would occur with simpler control methods
2Quantity of substance
If the exhaust valve of the idle cylinder is opened earlier than the intake valve during transition to all-cylinder operation, then the air replacement in the idle cylinder is improved, but the ignition period may be excessively retarded causing engine misfire
Solution Approach 1:
The patent opens the exhaust valve of the idle cylinder earlier than the intake valve during the transition to all-cylinder operation. This preliminary action allows residual burned gases to be expelled before fresh intake air enters the cylinder, improving air replacement efficiency and preventing misfire caused by excessive retained burned gases
Solution Approach 2:
The patent adjusts the ignition period based on the internal EGR (exhaust gas recirculation) gas amount in the idle cylinder during the transition. By dynamically changing the ignition timing parameter according to the actual amount of residual gases, the system optimizes combustion reliability while accommodating the variable air replacement conditions
Data Source
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Figure 3(a)~3(c)
AI summary
A control device for an engine includes a valve-stopping mechanism 14b which holds intake and exhaust valves 41, 51 of the first and the fourth cylinders (idle cylinders) of four cylinders in closed states, a throttle valve control unit 115, an ignition period control unit 113, and an ECU 110 which controls the valve-stopping mechanism 14b, the throttle valve control unit 115, and the ignition period control unit 113. The ECU 110 sets a retard amount of the ignition period of the idle cylinder behind the basic ignition period at least in starting the all-cylinder operation in accordance with an amount of burned gas existing in the idle cylinder in switching to the all-cylinder operation from the reduced-cylinder operation.