Evaporative Fuel Processing Device Lean Combustion Control
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Solution Overview
Problem
Existing evaporative fuel processing devices face challenges in accurately controlling the air-fuel ratio during lean combustion, leading to torque fluctuations and emission deterioration due to delays in fuel injection correction and lower detection accuracy of air-fuel ratios in lean combustion modes.
Innovation Solution
An evaporative fuel processing device with a purge control unit, air-fuel ratio detection unit, concentration learning unit, and injection control unit that estimates fuel concentration in purge gas and corrects fuel injection amounts based on concentration learning values, allowing for precise air-fuel ratio control and reducing delays in injection corrections during lean combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If evaporative fuel is adsorbed on a canister and supplied into the intake system during lean combustion, then fuel efficiency is improved, but air-fuel ratio control accuracy deteriorates leading to torque fluctuations
Solution Approach 1:
The system performs preliminary concentration learning of evaporative fuel before lean combustion operation. The ECU estimates the concentration of evaporative fuel in the purge passage based on air-fuel ratio changes detected during a learning period, and stores this concentration value for use during subsequent lean combustion, enabling accurate fuel injection control in advance
Solution Approach 2:
The ECU performs preliminary correction of the fuel injection amount based on the estimated evaporative fuel concentration before lean combustion begins. By calculating the required fuel injection amount considering the adsorbed evaporative fuel concentration in advance, the system eliminates delays in injection correction that would otherwise cause air-fuel ratio fluctuations during lean combustion
2Object-generated harmful factors
If fuel injection amount is corrected based on real-time air-fuel ratio detection during lean combustion, then emission control is improved, but response time is delayed due to lower detection accuracy in lean combustion modes
Solution Approach 1:
The system performs preliminary estimation of evaporative fuel concentration and preliminary correction of fuel injection amounts before lean combustion operation begins. The ECU calculates the fuel injection correction amount based on the estimated concentration during a learning period, storing this corrected value for immediate use during lean combustion, thereby eliminating response delays
Solution Approach 2:
The system uses feedback from air-fuel ratio detection during the learning period to estimate evaporative fuel concentration. The ECU detects air-fuel ratio changes, estimates the concentration of evaporative fuel in the purge passage, and uses this feedback to correct fuel injection amounts, creating a closed-loop control system that improves both emission control and 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
The device effectively suppresses air-fuel ratio fluctuations and improves emission control by accurately correcting fuel injection amounts during lean combustion, enhancing fuel efficiency and reducing NOx emissions.
Implementation Method 1
an adsorption unit, which is configured to adsorb evaporative fuel in a fuel tank
Data Source
AI summary
A purge control unit opens the purge control valve to supply, as purge gas to an intake passage, the evaporative fuel together with air in response to a predetermined purge request. An air-fuel ratio detection unit detects an air-fuel ratio of the internal combustion engine. A concentration learning unit estimates a fuel concentration in the purge gas based on a change in the air-fuel ratio when the purge control unit causes the purge gas to be supplied to the intake passage and to perform a fuel concentration learning to update a concentration learning value, which is a learning value of the fuel concentration in the purge gas, based on the estimated fuel concentration. An injection control unit corrects a fuel injection amount based on the concentration learning value in a period in which the concentration learning unit performs the fuel concentration learning in the lean combustion operation.