Intake Passage Pressure-Temperature Mapping for Transient Air-Fuel Control
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Solution Overview
Problem
Existing air-fuel ratio control methods for internal combustion engines fail to quickly set the air-fuel ratio to an appropriate condition during transient operation states such as rapid acceleration or deceleration, due to inaccuracies in estimating the in-cylinder inflow air flow rate.
Innovation Solution
A control device for internal combustion engines that includes an intake air flow rate acquisition unit, atmospheric pressure and temperature acquisition units, intake passage internal average pressure and temperature estimation units, and a spatial distribution estimation unit to accurately estimate the throttle valve passing flow rate, thereby improving in-cylinder inflow air flow rate estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional air-fuel ratio control methods are used, then the system is simple and easy to operate, but the air-fuel ratio cannot be quickly set to an appropriate condition during transient operation
Solution Approach 1:
The system performs preliminary calculation of the in-cylinder inflow air flow rate using a dynamic model before actual fuel injection occurs. By pre-calculating the required air flow rate based on throttle valve position, intake manifold pressure, and engine speed, the system prepares the control parameters in advance, enabling rapid response during transient operations without adding complex hardware.
Solution Approach 2:
The invention replaces mechanical measurement methods with electronic calculation and estimation. Instead of using complex mechanical flow meters or pressure sensors throughout the system, the control device uses electronic processors to calculate air flow rate based on readily available sensor data (throttle position, manifold pressure, engine speed), substituting mechanical complexity with computational simplicity.
2Measurement precision
If the in-cylinder inflow air flow rate is calculated from intake pipe pressure, then the calculation is simple, but the estimation accuracy is insufficient during transient operation
Solution Approach 1:
The system introduces an intermediary dynamic model that bridges the gap between simple pressure-based calculation and accurate flow rate measurement. The model uses intake manifold pressure as an intermediary variable, combined with throttle valve position and engine speed, to estimate the in-cylinder inflow air flow rate more accurately during transient conditions without requiring direct flow measurement hardware.
Solution Approach 2:
The invention changes the parameters used for estimation from static pressure-only measurements to a dynamic combination of pressure, throttle position, and engine speed. By incorporating multiple changing parameters that reflect the transient state of the engine, the system achieves higher estimation accuracy without adding complex measurement devices, simply by utilizing existing sensor data more effectively.
Data Source
AI summary
An intake air flow rate into an intake passage is detected with an internal combustion engine as a control device, and atmospheric pressure and temperature are estimated or detected. An intake passage internal average pressure and an intake passage internal average temperature in a region up to a throttle valve of the intake passage as one region are estimated. Distributions of a pressure and a temperature inside the intake passage are estimated based on the estimated intake passage internal average pressure, the intake passage internal average temperature, and a model of energy change caused by a constituent element included in the intake passage.