Cylinder Intake Gas Mass Estimation Under Transient Exhaust Conditions
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Solution Overview
Problem
Existing methods for determining the mass of gas aspirated into a combustion chamber of an internal combustion engine are inaccurate, particularly in real-world driving conditions, and do not account for transient phases, exhaust gas recirculation, and other dynamic factors, relying on complex and costly sensor setups and calibration protocols.
Innovation Solution
A method and system for determining and controlling the air and exhaust gas masses in the cylinder, using commonly available sensors, by integrating system dynamics, engine speed, intake manifold pressure and temperature, and exhaust conditions, with correction mechanisms for transient and exhaust pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If production-type sensors are used to measure intake air mass, then measurement reliability is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent uses readily available sensors (pressure, temperature, crank angle) as intermediaries to indirectly determine intake air mass through a physics-based model, avoiding the need for dedicated intake air mass sensors. The model acts as a mediator that transforms common measurements into accurate air mass estimates.
Solution Approach 2:
The patent replaces physical measurement sensors with a computational model based on thermodynamic and fluid mechanical principles. Instead of using specialized sensors to directly measure air mass, the system uses a mathematical model that calculates air mass from pressure, temperature, and valve timing data.
2Manufacturing precision
If steady-state models are used to describe intake performance, then manufacturing precision is improved, but adaptability to transient conditions deteriorates
Solution Approach 1:
The patent transforms a static steady-state model into a dynamic model that adapts to changing operating conditions. The model incorporates real-time measurements of pressure, temperature, and valve timing to continuously update air mass calculations, enabling accurate performance prediction during transient operations while maintaining the structural simplicity of steady-state approaches.
3Measurement precision
If calibration maps are used under laboratory conditions, then measurement precision is improved, but reliability under real-world conditions deteriorates
Solution Approach 1:
The patent moves from fixed calibration maps to a dynamic model where parameters are continuously updated based on real-time sensor measurements. The system adapts to varying exhaust pressure, temperature, and valve timing conditions by recalculating air mass using current operating parameters rather than relying on pre-established calibration data from laboratory conditions.
4Measurement precision
If complex signal processing techniques are used, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent extracts only the essential parameters needed for air mass calculation (pressure, temperature, valve timing, cylinder volume) from the complex engine operating data, eliminating the need for extensive signal processing. By focusing on the most critical inputs to the physics-based model, the system achieves accurate air mass determination with minimal computational overhead and rapid response time.
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
Provides an accurate model for intake gas mass estimation, minimizing sensor requirements and improving precision in torque and air-fuel ratio control, especially in variable valve timing engines.
Implementation Method 1
a mass of intake aspirated gas is determined from the combustion chamber volume when at least one intake valve is closed, the intake gas temperature and the intake gas pressure
Implementation Method 2
At high loads, it allows for taking advantage of the water hammer effect to maximize the fresh air intake
Implementation Method 3
modifying the valve overlap (the point at which both valves are open simultaneously) allows for internal exhaust gas recirculation. This phenomenon depends on the engine's operating conditions, as it is a function of the pressure difference between the intake and exhaust manifolds
Data Source
Figure 1~3
AI summary
The invention relates to a method for determining the mass of aspirated gas in a cylinder, taking into account the real conditions of use, in order to control the masses of air and gas burnt in a cylinder, by implementing a correction mechanism that is modelled as a function of the exhaust conditions, engine temperature conditions or a combination of the exhaust and engine temperature conditions.