Engine Purge Control via Catalyst Temperature Estimation
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Solution Overview
Problem
Existing engine control systems face challenges in managing the supply of purge gas during deceleration fuel cutoff, leading to potential degradation of emission performance due to excessive unburned evaporated fuel reaching the exhaust emission control catalyst, especially when the catalyst temperature is high.
Innovation Solution
A control system that adjusts the supply flow rate of purge gas to the intake passage based on the estimated temperature and purifying performance of the exhaust emission control catalyst, including modules for estimating evaporated fuel supply, catalyst temperature, and concentration, to optimize purge gas supply while preventing catalyst degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the supply flow rate of purge gas is increased to prevent evaporated fuel overflow from the canister, then the overflow of evaporated fuel is reduced, but excessive unburned evaporated fuel reaches the exhaust emission control catalyst causing degradation of emission performance
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the purge gas supply flow rate based on the exhaust emission control catalyst temperature. When the catalyst temperature is high, the purge gas supply flow rate is reduced to prevent excessive unburned evaporated fuel from reaching the catalyst and degrading emission performance. When the catalyst temperature is low, the purge gas supply flow rate is increased to effectively prevent evaporated fuel overflow from the canister. This dynamic parameter adjustment resolves the contradiction between preventing fuel overflow and maintaining emission performance.
2Object-generated harmful factors
If the supply flow rate of purge gas is reduced to protect the exhaust emission control catalyst from excessive unburned evaporated fuel, then emission performance degradation is suppressed, but the purging effectiveness decreases
Solution Approach 1:
The patent applies dynamics by making the purge gas supply flow rate variable rather than fixed. The control system continuously monitors the exhaust emission control catalyst temperature and dynamically adjusts the purge gas supply flow rate accordingly. This dynamic adjustment allows the system to maximize purging effectiveness when the catalyst temperature is low while protecting the catalyst and maintaining emission performance when the temperature is high, thus resolving the contradiction between purging effectiveness and emission performance protection.
3Reliability
If the purge gas supply is controlled based on catalyst temperature, then a sufficient supply of purge gas can be ensured while minimizing emission performance degradation, but the system complexity increases due to temperature estimation requirements
Solution Approach 1:
The patent applies mechanics substitution by replacing direct physical temperature sensors with a temperature estimation mechanism. Instead of installing additional hardware sensors in the exhaust system, the control system estimates the exhaust emission control catalyst temperature based on operating parameters such as engine load, speed, and exhaust gas conditions. This substitution maintains the benefits of temperature-based control while avoiding the complexity and cost of additional sensing hardware.
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
The system ensures a sufficient supply of purge gas to the intake passage while minimizing emission performance degradation by adjusting flow rates according to catalyst temperature and evaporated fuel concentration, thereby maintaining effective purifying performance and preventing catalyst deterioration.
Implementation Method 1
an exhaust emission control catalyst provided in the exhaust passage
Implementation Method 2
the unburned evaporated fuel reaches the exhaust emission control catalyst
Implementation Method 3
a canister in which evaporated fuel is desorbed
Data Source
AI summary
A control system of an engine is provided. The control system includes an exhaust emission control catalyst provided in an exhaust passage, a deceleration fuel cutoff module for performing a deceleration fuel cutoff when a deceleration fuel cutoff condition is satisfied in an engine decelerating state, a purging unit for performing a purge to supply a purge gas to an intake passage during the deceleration fuel cutoff, an evaporated fuel supply amount estimating module for estimating a supply amount of evaporated fuel to the intake passage when the purge is performed, and a catalyst temperature estimating module for estimating a temperature of the exhaust emission control catalyst when the purge is performed, based on the supply amount of the evaporated fuel. The purging unit controls a supply flow rate of the purge gas to the intake passage when the purge is performed, based on the exhaust emission control catalyst temperature.