Direct Injection Engine Control for Stable Idle Stop Restart
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Solution Overview
Problem
Direct injection engines with idle stop functionality face challenges in achieving stable combustion and preventing soot emission due to varying piston positions and low engine rotation, leading to poor exhaust performance and fuel efficiency when restart requests are made before engine stop.
Innovation Solution
A control device for direct injection engines that adjusts the number of fuel injections and air/fuel ratio based on piston position during restart requests, determining an optimal restart combustion mode through computational performance to ensure stable combustion and improved exhaust performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fuel injection is performed with fixed injection timing and quantity regardless of piston position, then the control system is simple, but combustion becomes unstable and soot emission increases at extremely low rotation
Solution Approach 1:
The patent implements dynamic fuel injection control that adapts injection timing, quantity, and strategy based on real-time piston position detection and engine rotation speed. The ECU modifies injection parameters dynamically across different compression strokes, transitioning from fixed to variable control to maintain stable combustion at extremely low rotation speeds
Solution Approach 2:
The system changes multiple fuel injection parameters including injection timing, injection quantity, and injection strategy based on detected piston position. At different compression stroke positions, the ECU adjusts these parameters to optimize combustion, thereby preventing soot emission while maintaining combustion stability at low rotation
2Use of energy by moving object
If the number of idle stop conditions is increased to improve fuel efficiency, then fuel consumption decreases, but combustion stability deteriorates due to varying piston positions and low rotation speeds
Solution Approach 1:
The system performs preliminary detection of piston position before fuel injection occurs during restart. By detecting the compression stroke piston position in advance and preparing appropriate injection parameters, the system ensures stable combustion when restart is requested, enabling more frequent idle stop conditions while maintaining reliability
Solution Approach 2:
The ECU continuously monitors piston position, engine rotation speed, and combustion status, then adjusts fuel injection parameters in real-time based on this feedback. This closed-loop control ensures that even with increased idle stop frequency causing varying restart conditions, the system maintains stable combustion by adapting to each specific situation
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
The solution enables stable combustion and enhanced fuel efficiency by optimizing fuel injection strategies based on piston position, reducing soot emission and improving exhaust performance during engine restarts.
Implementation Method 1
an injector directly injecting fuel into a combustion chamber
Implementation Method 2
a stop position of a piston of a certain cylinder is a stop position in which compression injection combustion can be performed
Data Source
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AI summary
Provided is a control device of a direct injection engine (1), the control device that can prevent the amount of emission of soot from increasing and the exhaust performance from worsening when a restart request is made before an engine (1) is stopped after an idle stop condition is satisfied. When a restart request is made before an engine (1) is stopped after an idle stop condition is satisfied, at least one of the number of fuel injections in one combustion cycle and the air/fuel ratio of an air fuel mixture used for combustion is changed for each cylinder according to a piston (207a) position at that time.