Selective Cylinder Pressure Sensor Placement for Engine Combustion Control
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Solution Overview
Problem
The increasing demand for lower engine emission standards requires sophisticated engine controls, but installing pressure sensors in each engine cylinder is costly and computationally intensive, necessitating a more efficient method to improve combustion without full sensor coverage.
Innovation Solution
Evaluating engine cylinders based on crankshaft signals to selectively install pressure sensors in those providing the lowest root mean square error values, allowing for improved combustion control across all cylinders using feedback from a subset of sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are installed in each engine cylinder, then combustion control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies partial action by installing pressure sensors in only a subset of engine cylinders rather than all cylinders. The system evaluates crankshaft signals to identify which cylinders provide the lowest root mean square error values, then selectively instruments those cylinders with pressure sensors. This partial instrumentation achieves sufficient combustion control precision while reducing device complexity and cost compared to full cylinder coverage.
Solution Approach 2:
The patent makes the pressure sensor system universal by using data from sensors in selected cylinders to control combustion across all engine cylinders. The controller uses feedback from the subset of instrumented cylinders to adjust fuel injection timing and quantity for the entire engine, making the measurement system applicable to all cylinders without requiring physical sensors in each one.
2Measurement precision
If pressure sensors are installed in each engine cylinder, then combustion control precision is improved, but computational power requirements increase
Solution Approach 1:
The patent reduces computational power requirements by processing data from only a subset of cylinders equipped with pressure sensors. The controller evaluates crankshaft signals and selects cylinders with the lowest root mean square error values, then processes pressure data only from those selected cylinders. This partial data processing approach maintains combustion control precision while significantly reducing the computational burden compared to processing data from all cylinders.
3Productivity
If pressure sensors are installed in more cylinders, then combustion improvement extent is improved, but device complexity increases
Solution Approach 1:
The patent optimizes the balance between combustion improvement extent and device complexity by installing pressure sensors in a specific subset of cylinders rather than all cylinders or just one cylinder. The system identifies cylinders providing the lowest root mean square error values and instruments those with pressure sensors, achieving greater combustion improvement than single-cylinder instrumentation while avoiding the complexity of full multi-cylinder instrumentation.
Solution Approach 2:
The patent changes the parameter of sensor distribution from uniform (all or none) to selective (based on performance evaluation). By evaluating crankshaft signals and selecting cylinders with optimal characteristics (lowest root mean square error values), the system optimizes the number and location of pressure sensors to achieve maximum combustion improvement per sensor installed, effectively changing the density and distribution parameter of the sensing system.
Data Source
AI summary
Methods and systems for evaluating cylinder pressure profiles in cylinders of an engine are disclosed. In one example, fuel injection timing of engine cylinders is adjusted to improve engine combustion in response to output of one or more pressure sensors installed in engine cylinders. Combustion within a plurality of engine cylinders may be adjusted in response to pressure sensed in a single engine cylinder.