Engine Control Apparatus for Transient Response Following
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Solution Overview
Problem
Existing engine control systems face challenges in accurately following target values for Mass Air Flow (MAF) and Manifold Air Pressure (MAP) during transient states, leading to emission increases and fuel efficiency deterioration due to dynamic characteristics like first-order time-lags in turbo engine responses.
Innovation Solution
The solution involves compensating the transient response characteristic of the engine by calculating dynamic feedforward amounts and adjusting the nozzle opening degree of the Variable Nozzle Turbo (VNT) and the valve opening degree of the Exhaust Gas Recirculator (EGR) using transfer functions to achieve a desired transient response, thereby improving followingness and enabling high-speed responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional feedback control is used to maintain steady-state MAP and MAF, then emission control is improved, but transient response followingness deteriorates due to first-order time-lag in turbo engine dynamics
Solution Approach 1:
The patent applies feedforward control that calculates and applies control amounts in advance based on anticipated changes in injection quantity and engine speed. The controller pre-compensates for the known first-order time-lag characteristics of the turbo system, allowing the MAP and MAF to follow target values more accurately during transient states without waiting for feedback errors to develop.
Solution Approach 2:
The patent combines feedforward control with feedback control in a hybrid architecture. The feedback component continuously monitors actual MAP and MAF values against target values and corrects deviations, ensuring emission control requirements are met. The feedforward component anticipates transient behavior and proactively adjusts control, resolving the contradiction between steady-state reliability and transient response speed.
2Use of energy by moving object
If target values for MAP and MAF are changed according to driving conditions, then fuel efficiency is improved, but transient errors occur due to dynamic characteristics of the turbo system
Solution Approach 1:
When target MAP and MAF values change according to driving conditions, the feedforward controller anticipates the transient response based on the known first-order time-lag characteristics. It pre-calculates the control amounts needed to achieve smooth transitions, preventing target value following errors and maintaining optimal fuel efficiency during transient states.
Solution Approach 2:
The patent dynamically adjusts control parameters including feedforward control amounts, feedback control gains, and target values based on operating conditions such as injection quantity and engine speed. This adaptive parameter adjustment ensures accurate target following across different transient scenarios while maintaining fuel efficiency optimization.
3Reliability
If VNT and EGR are controlled independently for PM and NOx reduction, then emission control is improved, but transient coordination between the two systems deteriorates
Solution Approach 1:
The patent merges the control of VNT and EGR into a unified control framework that calculates feedforward control amounts for both actuators simultaneously. The controller considers the interaction between VNT and EGR during transient states, coordinating their actions to achieve both PM and NOx reduction goals while maintaining simple and effective control logic.
Data Source
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Figure 2
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AI summary
A dynamic feedforward amount to realize a predetermined transient response characteristic by compensating a transient response characteristic of an engine having a Vriable Nozzle Turbo (VNT) and an Exhaust Gas Recirculator (EGR) is calculated for a nozzle opening degree of the VNT and a valve opening degree of the EGR. The transient response characteristic of the engine responds to a setting value of an injection quantity or the like. Then, command values of the nozzle opening degree of the VNT and the valve opening degree of them EGR are calculated by using the dynamic feedforward amount. In the transient state, the followingness to the target value is improved.