Hybrid Engine Restart Injection Control for Pre-Ignition Suppression
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Solution Overview
Problem
In engine devices with hybrid electric vehicles, there is a concern about pre-ignition occurring when fuel injection and ignition are resumed after a fuel supply cutoff and clutch release, particularly when intake manifold pressure is high, leading to potential torque output issues.
Innovation Solution
The engine device controls fuel injection timing and amount in the target cylinder to be later or larger when the required rotation time exceeds a threshold, using an in-cylinder injection valve and a control device to manage the engine, motor, and clutch, thereby reducing the likelihood of pre-ignition by increasing latent heat of vaporization and managing intake manifold pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel injection timing is advanced or fuel injection amount is reduced to improve engine startup performance and torque output, then engine startup speed and torque output are improved, but combustion chamber temperature rises and pre-ignition occurs
Solution Approach 1:
The control device dynamically adjusts fuel injection timing and injection amount based on the required rotation time parameter. When required rotation time exceeds the threshold, the system retards injection timing and increases injection amount, thereby changing the combustion parameters to suppress pre-ignition while still achieving reliable engine startup under varying operational conditions.
Solution Approach 2:
The system implements dynamic control of fuel injection parameters based on real-time assessment of required rotation time. The control device continuously monitors engine startup conditions and adjusts injection timing and amount accordingly, transitioning between different injection strategies based on whether the required rotation time exceeds the threshold, thereby adapting to changing operational requirements.
2Power
If intake manifold pressure is increased to improve torque output, then engine torque output is improved, but the likelihood of pre-ignition increases
Solution Approach 1:
The control device adjusts fuel injection timing and amount as compensatory parameters in response to intake manifold pressure changes. When high intake manifold pressure conditions are detected (which increase pre-ignition risk), the system modifies injection parameters to counteract the temperature rise, thereby maintaining torque output while suppressing pre-ignition.
3Reliability
If fuel injection timing is retarded or fuel injection amount is increased to suppress pre-ignition, then pre-ignition is suppressed, but engine startup performance may be reduced
Solution Approach 1:
The system implements conditional dynamic control where fuel injection timing and amount are adjusted based on the required rotation time threshold. This dynamic approach ensures that pre-ignition suppression measures are applied only when necessary (when required rotation time exceeds threshold), thereby avoiding unnecessary degradation of engine startup performance while maintaining reliability.
Solution Approach 2:
The control device changes fuel injection parameters (timing and amount) as a function of the required rotation time parameter. By establishing a threshold-based control strategy, the system optimizes the balance between pre-ignition suppression and startup performance, applying parameter changes only when the operational conditions warrant such adjustments.
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 effectively suppresses pre-ignition by adjusting fuel injection parameters, ensuring reliable engine startup and torque output while minimizing the risk of combustion chamber temperature rise.
Implementation Method 1
the amount of latent heat of vaporization of fuel injected from the fuel injection valve increases, and the temperature in a combustion chamber can be restrained from rising
Data Source
AI summary
A fuel injection timing is made later and/or a fuel injection amount is made larger in a target cylinder to be subjected to explosive combustion subsequently, when a required rotation time that is a time required for rotation of an output shaft by a predetermined rotational angle is equal to or longer than a time threshold than when the required rotation time is shorter than the time threshold, at the time of predetermined startup control in which an engine and a clutch are controlled such that fuel injection and ignition in the engine are resumed from a state where the supply of fuel to the engine is cut off and the clutch is released and that the clutch is then engaged.