Supercharger Throttle Upstream Pressure Estimation
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Solution Overview
Problem
Existing control systems for internal combustion engines with superchargers face increased calculation loads and accuracy issues when estimating throttle upstream pressure, often requiring additional sensors that increase cost and complexity.
Innovation Solution
A control device and method that utilize first and second temperature sensors and air pressure sensors on either side of the supercharging path to calculate inflow and outflow air masses, select the appropriate air mass based on engine load state, and calculate throttle upstream pressure using the selected air mass and downstream temperature, thereby reducing calculation load and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor for measuring the pressure upstream of the throttle valve is provided, then the measurement precision of throttle upstream pressure is improved, but the device complexity and cost increase
Solution Approach 1:
The patent uses atmospheric density as an intermediary parameter to estimate throttle upstream pressure. Instead of directly measuring pressure with a sensor, the system calculates pressure based on the relationship between atmospheric density, throttle valve opening area, and air flow characteristics. This intermediary approach eliminates the need for a dedicated pressure sensor while maintaining measurement capability.
Solution Approach 2:
The patent replaces the mechanical pressure sensing system with a computational estimation system. By using the equation of state for gases and mass flow conservation principles, the system substitutes physical measurement with mathematical calculation, deriving pressure from measurable parameters such as atmospheric density and throttle valve geometry.
2Device complexity
If throttle upstream pressure is estimated based on intake manifold pressure and average atmospheric density, then the device complexity is reduced, but the calculation load increases due to complicated calculations
Solution Approach 1:
The patent changes the approach by using directly measurable parameters (atmospheric density, throttle valve opening area) rather than requiring complex transformations of multiple measured values. By formulating the pressure estimation as a direct function of these simple parameters, the calculation becomes more efficient while avoiding the need to process multiple sensor inputs through complex algorithms.
3Productivity
If throttle upstream pressure is estimated using atmospheric density and throttle valve opening area, then the calculation load is reduced, but the measurement precision may be compromised
Solution Approach 1:
The patent incorporates feedback mechanisms where the estimated throttle upstream pressure is used to adjust and refine subsequent calculations. The system continuously refines the pressure estimation by comparing calculated values with actual engine operating conditions, thereby improving accuracy over time without requiring additional sensors or increasing calculation complexity.
Data Source
AI summary
In a control device and method for an internal combustion engine with a supercharger, a first/second temperature sensor and a first/second air pressure sensor are respectively provided on an upstream/downstream side of a supercharging path from a compressor to a throttle valve. A control portion calculates an inflow air mass to the supercharging path and an outflow air mass from the supercharging path, calculates a throttle upstream air mass in a high operational load state from those air masses, calculates a throttle upstream air mass in a low operational load state from outputs of the first temperature sensor and the first air pressure sensor, selects either one of the throttle upstream air masses depending on an operational load state of the engine, and calculates a throttle upstream pressure based on the upstream air mass selected and a second temperature detected by the second temperature sensor.