Cylinder Air Mass Estimation Without an Intake Flow Meter
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Solution Overview
Problem
Existing air flow meters in internal combustion engines are expensive and prone to being contaminated by oil vapors and dust, leading to inaccurate air flow rate measurements, which affects the determination of fuel injection quantities.
Innovation Solution
A method using an electronic control unit with a calculation model to determine the mass of air trapped in each cylinder, utilizing sensors for pressure, temperature, and VVT device data, without relying on an air flow meter, and applying the ideal gas law adjusted for engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an air flow meter is used to measure fresh air flow rate, then measurement precision is improved, but device complexity and cost increase, and reliability deteriorates due to contamination by oil vapors and dust
Solution Approach 1:
The patent extracts the air flow measurement function from the physical air flow meter sensor and relocates it to the electronic control unit through calculation. Instead of measuring air flow directly with a sensor in the intake duct, the system calculates air mass using pressure and temperature sensors combined with engine operating parameters, thereby removing the vulnerable air flow meter from the contaminated environment while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical air flow meter with an electronic calculation-based system. The air mass determination is performed through computational algorithms in the electronic control unit that process data from pressure sensors, temperature sensors, and engine operating parameters, substituting direct mechanical measurement with indirect electronic computation
2Measurement precision
If an air flow meter is used to measure fresh air flow rate, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces the expensive air flow meter with a combination of inexpensive pressure and temperature sensors that are already present in modern engines. These sensors are significantly cheaper than air flow meters and can be easily replaced if needed, reducing the overall manufacturing cost while maintaining the capability to determine air mass for fuel injection control
Solution Approach 2:
The patent makes existing pressure and temperature sensors serve multiple functions: they not only monitor general engine operating conditions but also enable air mass calculation for fuel injection control. This multi-functionality eliminates the need for dedicated expensive sensors, reducing manufacturing costs while maintaining measurement precision
3Measurement precision
If an air flow meter is used to measure fresh air flow rate, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the air mass measurement function with the existing engine control system. The electronic control unit that already manages fuel injection and engine operation is enhanced with calculation algorithms that process data from existing pressure and temperature sensors, combining multiple functions into a single integrated system rather than adding separate dedicated measurement devices
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 and cost-effective means to calculate air mass in each cylinder, enabling precise fuel injection control and achieving the desired air/fuel ratio, thus improving engine performance.
Implementation Method 1
calculating, based on a calculation model using measured and/or estimated physical quantities, the mass m of air trapped in each cylinder 3
Data Source
Figure 1~4
Figure 2
Figure 5
AI summary
It is described a method to determine a mass (m) of air trapped in each cylinder (3) of an internal combustion engine (1); wherein the internal combustion engine comprises a number of cylinders, each one of the number of cylinders connected to an intake manifold (4), from which each one of the number of cylinders receives fresh air through at least one respective intake valve (5), and to an exhaust manifold (6), into which each one of the number of cylinders introduces exhaust gases produced by combustion through at least one respective exhaust valve (7); and wherein the at least one respective intake valve and/or at least one respective exhaust valve are controlled so as to change a timing thereof.