Engine Control Device Ignition Timing MBT Region
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control methods for internal combustion engines face challenges in stabilizing combustion and suppressing NOx emissions while maintaining a high efficiency, particularly in lean combustion conditions, due to increased computational load on the Engine Control Unit (ECU) and sensitivity to measurement errors in combustion pressure.
Innovation Solution
A control device and method that utilizes a combustion pressure estimation sensor and a crank angle sensor to set and maintain the MBT region by calculating the ignition delay period and combustion period, allowing for precise control of the ignition timing within this region to stabilize combustion and reduce NOx emissions without overburdening the ECU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat release rate is calculated from combustion pressure to detect CA10 and suppress misfire, then misfire suppression is improved, but ECU mounting load increases and measurement error sensitivity increases
Solution Approach 1:
The patent extracts only the necessary timing information (ignition delay period and combustion period) from the combustion pressure signal, rather than calculating the full heat release rate. This is achieved by detecting the crank angle corresponding to the maximum value of the second derivative of combustion pressure, which provides sufficient information for MBT control without the computational burden of complete heat release rate calculation.
Solution Approach 2:
The patent uses a simplified calculation approach that requires less computational resources. By focusing only on detecting specific crank angle timings from the combustion pressure signal rather than performing continuous heat release rate integration, the ECU computational load is significantly reduced while maintaining control effectiveness.
2Loss of energy
If super-lean combustion with high excess air ratio is used to improve thermal efficiency and reduce pumping loss, then thermal efficiency is improved, but combustion stability deteriorates and NOx emissions increase
Solution Approach 1:
The patent implements feedback control by continuously monitoring the combustion pressure, calculating the ignition delay period and combustion period, and comparing these values against predetermined ranges. When the calculated values fall outside the acceptable ranges, the ECU adjusts the ignition timing to bring the combustion parameters back within the optimal MBT region, thereby maintaining combustion stability under super-lean conditions.
Solution Approach 2:
The patent dynamically adjusts the ignition timing parameter based on real-time combustion conditions. By changing the ignition timing to keep the combustion period within a predetermined range, the system maintains stable combustion even at high excess air ratios where combustion stability would otherwise deteriorate.
3Reliability
If ignition timing is precisely controlled within MBT region to stabilize combustion and reduce NOx, then combustion stability and emission control are improved, but control system complexity increases
Solution Approach 1:
The patent applies local quality by using different control strategies for different combustion conditions. Instead of implementing a universally complex control system, it uses a simplified calculation method (detecting maximum second derivative points) that is sufficient for maintaining MBT operation, while only adding complexity when necessary for feedback adjustment.
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 stabilizes combustion and suppresses NOx emissions while maintaining high engine efficiency, reducing the computational load on the ECU and improving the accuracy of combustion control.
Implementation Method 1
a combustion pressure estimation sensor that detects a combustion pressure in the combustion chamber
Implementation Method 2
a crank angle sensor that detects a crank angle of a crankshaft
Implementation Method 3
an ignition plug that ignites an air-fuel mixture of fuel and air in the combustion chamber
Implementation Method 4
a combustion chamber, and a crankshaft that rotates in accordance with an expansion force of the combustion
Data Source
AI summary
Provided is a control device and a control method of a high-efficiency internal combustion engine capable of stabilizing combustion and suppressing NOx emissions without unnecessarily increasing a mounting load on an ECU. Therefore, the control device of the internal combustion engine for controlling the internal combustion engine includes an ignition plug that ignites an air-fuel mixture of fuel and air in the combustion chamber, a combustion pressure estimation sensor that detects a combustion pressure in the combustion chamber, and a crank angle sensor that detects a crank angle of a crankshaft. An MBT region is set based on an ignition delay period from an ignition timing of the ignition plug calculated from a detection value of the combustion pressure estimation sensor and a detection value of the crank angle sensor to a combustion start timing in the combustion chamber, and a combustion period from the combustion start timing to a set amount combustion end timing when a set amount of combustion ends. An ignition timing of the ignition plug is controlled so as to fall within the set MBT region.