In-Cylinder Pressure Sensor Combustion Control
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Solution Overview
Problem
Modern diesel engines face challenges in meeting emissions standards without the use of after-treatment systems, such as SCR systems, which increase operating costs and complexity, and require periodic catalyst replenishment to control NOx and particulate matter emissions.
Innovation Solution
A control system for internal combustion engines that utilizes in-cylinder pressure sensors to monitor combustion and adjust fuel injection timing and EGR valve positions dynamically, allowing for high EGR rates and fuel injection after top dead center, ensuring stable combustion and reduced emissions without the need for after-treatment systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an SCR system is used to control NOx emissions, then emissions standards are met, but device complexity and operating costs increase
Solution Approach 1:
The patent extracts the emissions control function from the exhaust system and relocates it to the combustion chamber. By implementing combustion control that achieves low NOx formation directly in the cylinder through optimized injection timing and high EGR rates, the complex after-treatment SCR system becomes unnecessary and can be removed from the vehicle system.
Solution Approach 2:
The patent converts the typically harmful effect of EGR (which can degrade combustion) into a benefit by using high EGR rates to suppress NOx formation at the source. The exhaust gas recirculation, which normally reduces combustion efficiency, is optimized to achieve both emissions reduction and acceptable combustion performance through precise control of injection timing and combustion phasing.
2Object-affected harmful factors
If high EGR rates are used in combustion, then NOx emissions are reduced, but combustion stability deteriorates
Solution Approach 1:
The patent implements dynamic control of combustion parameters including variable injection timing, adjustable EGR rates, and real-time combustion phasing control. The system continuously adapts injection strategies based on operating conditions to maintain stable combustion across varying loads and speeds while achieving low NOx emissions through optimized combustion timing.
Solution Approach 2:
The patent changes key combustion parameters including delaying injection timing to after top dead center, increasing EGR rates to high levels, and optimizing combustion phasing (CA50). These parameter changes fundamentally alter the combustion process to achieve low NOx formation while maintaining stability through precise control of the modified combustion characteristics.
3Object-affected harmful factors
If fuel injection begins after top dead center, then NOx emissions are reduced, but misfire risk increases
Solution Approach 1:
The patent implements feedback control using in-cylinder pressure sensors to monitor combustion events in real-time. The measured pressure data provides feedback on combustion quality and timing, allowing the control system to detect misfire conditions and adjust injection timing and duration to prevent misfires while maintaining the beneficial late injection strategy for NOx reduction.
Solution Approach 2:
The system performs preliminary assessment of combustion conditions using in-cylinder pressure measurements to predict potential misfire risks before they occur. Based on this preliminary information, the control system proactively adjusts injection parameters to ensure reliable combustion while maintaining the low NOx injection timing strategy.
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 system effectively reduces NOx and particulate matter emissions by stabilizing combustion with high EGR rates and adjusting fuel injection timing, maintaining engine performance and compliance with emissions standards without the reliance on SCR systems.
Implementation Method 1
pressure sensing means for generating in-cylinder pressure data for calculating a total heat generated during a combustion cycle
Implementation Method 2
An angular position of a crankshaft of the engine is monitored using a crank position sensor
Implementation Method 3
A fuel injection system having a plurality of fuel injectors, each fuel injector associated with a respective cylinder of the plurality of cylinders
Implementation Method 4
Many modern diesel engines have an exhaust system that features an exhaust gas recirculation ('EGR') system that routes a portion of engine exhaust gas into an air intake system
Implementation Method 5
The present disclosure relates to a system and method of controlling combustion within an internal combustion engine
Data Source
AI summary
A control system for an internal combustion engine comprises pressure sensing means, memory means, processing means, and fuel injection control means. Pressure sensing means generate in-cylinder pressure data used to calculate total heat generated during combustion cycle. Memory means store predetermined crank angle data, such as CA50 crank angle data, for variety of engine operating conditions. A CA50 crank angle is a crank angle position where fifty percent of total heat is generated. Memory means additionally stores allowable start of injection crank angle data. Processing means determine an observed CA50 crank angle. Processing means conducts comparison of at least one of the predetermined CA50 crank angle data against the observed CA50 crank angle to generate a start of fuel injection crank angle which impacts the observed CA50 crank angle during subsequent combustion cycle. Fuel injection control means controls start of fuel injection crank angle generated by the processing means.