Engine Controller Combustion Stability via Valve Timing Advance
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Solution Overview
Problem
Conventional engine systems face challenges in maintaining stable compressed self-ignition combustion during transition states due to changes in in-cylinder properties, particularly influenced by the response delay of intake and exhaust valve operating mechanisms.
Innovation Solution
An engine system with a controller that manages the operations of injectors, spark plugs, intake valves, and exhaust valves to set and maintain target in-cylinder properties by estimating current properties and adjusting valve operating amounts, accounting for response delays and deviations to ensure accurate and stable combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intake valve operating mechanism and exhaust valve operating mechanism are controlled to adjust in-cylinder properties for CI combustion, then combustion stability is improved, but the response delay of these mechanisms causes inaccuracy in forming target in-cylinder properties during transition states
Solution Approach 1:
The controller sets the target in-cylinder property and target operating amount in advance for a specific future cycle based on current accelerator opening detection. This preliminary action allows the valve operating mechanisms to be activated with sufficient lead time, compensating for their response delay and ensuring accurate formation of target in-cylinder properties when needed for stable CI combustion.
Solution Approach 2:
The system calculates the required operating amounts of intake and exhaust valves in advance, creating a buffer that accounts for the inherent response delay of the valve operating mechanisms. This beforehand cushioning ensures that even during transition states with rapid accelerator operations, the target in-cylinder properties are formed accurately without combustion instability.
2Reliability
If the controller adjusts valve operating amounts in real-time to maintain target in-cylinder properties, then combustion stability is improved, but the complexity of the control system increases
Solution Approach 1:
The controller performs target load setting, combustion schedule setting, in-cylinder property estimation, target property setting, and target operating amount setting in a structured sequence for future cycles. This preliminary calculation approach consolidates control decisions, reducing the need for complex real-time adjustments while maintaining combustion stability through advance planning.
Solution Approach 2:
The system uses detected accelerator opening and estimated in-cylinder properties as feedback to continuously update target operating amounts. This feedback mechanism allows the controller to adapt to changing operating conditions while maintaining a manageable control structure based on established relationships between accelerator input and valve operating requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach stabilizes compressed self-ignition combustion during transition states by accurately setting and maintaining target in-cylinder properties, improving combustion stability and drivability by anticipating and adjusting for delays and deviations in valve operations.
Implementation Method 1
fuel injected into a cylinder from the injector is combusted by being ignited by the spark plug
Implementation Method 2
fuel injected into the cylinder from the injector carries out compressed self-ignition, without being ignited by the spark plug
Data Source
AI summary
An engine system is provided, which includes a vehicle-mounted engine having an injector, a spark plug, an intake valve operating mechanism, and an exhaust valve operating mechanism, an accelerator opening sensor, and a controller. The engine is configured to execute flame propagation combustion and compressed self-ignition combustion. The controller performs a combustion control so that a target torque set based on an accelerator opening is realized in a specific cycle in the future from a present time by a given delay time. The controller sets beforehand the combustion mode based on a target load, estimates an in-cylinder property when the intake valve is closed in the present cycle, sets a target in-cylinder property so that the set combustion mode is realized in the specific cycle, and sets a target operating amount of each of the intake and exhaust valve operating mechanisms based on the set target in-cylinder property.