Internal Combustion Engine Emission Estimation Without Cylinder Pressure Sensors
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Solution Overview
Problem
Internal combustion engines face challenges in accurately evaluating and reducing polluting emissions without relying on pressure sensors, which are costly and prone to damage, and existing methods require extensive calibration and computation resources.
Innovation Solution
An internal combustion engine system that estimates pollutant emissions using existing sensors, such as those for engine control, by calculating emission values based on engine speed, coolant temperature, fuel consumption, and gas mixture richness, without relying on pressure measurements, and incorporates a regulator to adjust engine operation for reduced emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are used to measure cylinder pressure for emission evaluation, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses an intermediary approach by measuring manifold pressure and temperature as proxy variables instead of directly measuring cylinder pressure. These intermediary measurements, combined with engine operating parameters, allow estimation of cylinder conditions and pollutant emissions without requiring direct cylinder pressure sensors, thus reducing system complexity while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical pressure sensor system with a computational estimation system. Instead of using physical sensors in the cylinders to directly measure pressure, the system uses mathematical models that process data from existing sensors (manifold pressure, temperature, flow meters) to estimate cylinder pressure and emissions, substituting mechanical measurement with computational analysis
2Measurement precision
If pressure sensors are installed in cylinders for emission monitoring, then measurement precision is improved, but reliability deteriorates due to sensor damage from high pressure and temperature
Solution Approach 1:
The patent extracts the measurement function from the harsh cylinder environment and relocates it to the intake manifold environment. By measuring manifold pressure and temperature instead of cylinder pressure directly, the system removes the sensor exposure to high-temperature, high-pressure conditions that cause sensor damage, thereby improving reliability while still enabling emission estimation
Solution Approach 2:
The patent uses manifold pressure and temperature as intermediary variables that correlate with cylinder conditions but can be measured in a less harsh environment. These intermediary measurements serve as proxies for cylinder state, allowing emission monitoring without placing sensors directly in the damaging cylinder environment
3Device complexity
If existing sensor data is used for emission estimation instead of pressure sensors, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent transforms the estimation approach by changing from direct measurement to multi-parameter computational estimation. It combines multiple parameters (manifold pressure, manifold temperature, coolant temperature, engine speed, fuel injection quantity, air flow) and uses thermodynamic relationships to calculate equivalent cylinder conditions and emission rates, achieving accurate emission evaluation through parameter transformation rather than direct sensing
Solution Approach 2:
The patent makes the existing sensor system multi-functional by using sensors originally intended for basic engine control (manifold pressure, temperature, flow meters) to also perform emission monitoring and evaluation. This universal use of existing sensors eliminates the need for dedicated emission sensors while maintaining measurement capability through sophisticated data processing
4Measurement precision
If sophisticated emission estimation models are implemented, then measurement precision is improved, but computation capacity requirements increase
Solution Approach 1:
The patent applies partial action by implementing emission estimation only for the most significant pollutants (NOx, CO, HC) based on dominant combustion conditions, rather than attempting to model all emission species. The system focuses computational resources on the primary emission sources identified by the operating parameters, achieving sufficient precision for emission control without exhaustive computation
Data Source
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AI summary
The invention relates to a method for managing an internal combustion engine (1), which involves estimating at least one value (Pollut) of emission of a pollutant species by means of engine parameters other than the gas pressure in the cylinders (6) of the engine (1), at least one first value of pollutant emissions being calculated as the product of a first affine function of fuel consumption (Qcarb), a second affine function of the spark advance function (φ) of the engine, a third affine function of the temperature (T) of the coolant of the engine, and a negative exponential term of a power of the richness (R) of the comburent mixture in the cylinders (6) of the engine.