Engine Control Device Switching Between Throttle and EGR Valves
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Solution Overview
Problem
Existing control systems for internal combustion engines face challenges in ensuring control responsiveness and fuel efficiency during switching between fresh air amount control using a diesel throttle valve and an EGR valve, as they often result in insufficient differential pressure across valves, leading to compromised performance and increased fuel consumption.
Innovation Solution
A control device that calculates and maintains target differential pressures across both the throttle valve and EGR valve to ensure optimal control responsiveness and fuel efficiency by switching between throttle valve and EGR valve fresh air amount control based on actual differential pressures, thereby maintaining minimum required pressures during feedback control function switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the control system switches between throttle valve control and EGR valve control for fresh air amount regulation, then the adaptability to different operating conditions is improved, but the control responsiveness deteriorates due to insufficient differential pressure across the valves
Solution Approach 1:
The control device calculates target differential pressures for both the throttle valve and EGR valve in advance, before switching between control modes. This preliminary calculation ensures that when switching occurs, the differential pressure requirements are already established, preventing the loss of control responsiveness that would otherwise occur during mode transitions.
Solution Approach 2:
The system dynamically adjusts the differential pressure parameters for both valves based on operating conditions and control mode. By changing the target differential pressure parameters appropriately before and during switching, the system maintains optimal control responsiveness across different operating conditions while preserving the adaptability benefits of multi-mode control.
2Speed
If the control system maintains higher differential pressure across valves to ensure control responsiveness, then the control responsiveness is improved, but the fuel efficiency deteriorates due to increased pressure losses
Solution Approach 1:
The control device dynamically adjusts the target differential pressure for each valve based on real-time operating conditions and control mode. Rather than maintaining a fixed high differential pressure, the system optimizes the differential pressure level dynamically - using higher values when control responsiveness is critical and lower values when fuel efficiency is the priority, thus resolving the contradiction between these two parameters.
Solution Approach 2:
The system changes the differential pressure parameters adaptively based on operating conditions. By adjusting the target differential pressure values according to the specific operating state and control mode, the system achieves optimal control responsiveness only when necessary, thereby minimizing energy losses and improving fuel efficiency while maintaining adequate responsiveness.
3Measurement precision
If the control system uses both throttle valve and EGR valve for feedback control, then the control precision is improved, but the device complexity increases due to coordinated control requirements
Solution Approach 1:
The control device segments the control functions by assigning primary control responsibility to one valve (throttle or EGR) based on operating conditions, while using the other valve primarily for differential pressure maintenance. This segmentation simplifies the control logic compared to coordinating both valves equally for precision control, reducing system complexity while maintaining adequate control precision through the specialized division of roles.
Data Source
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AI summary
A control device switches to an EGR valve fresh air amount control for controlling a fresh air amount by using an EGR valve in a case where a differential pressure across a Dth valve falls below a minimum differential pressure across the Dth valve during execution of a Dth valve fresh air amount control for controlling the fresh air amount by using the Dth valve. In addition, the control device switches to the Dth valve fresh air amount control in a case where a differential pressure across the EGR valve falls below a minimum differential pressure across the EGR valve during execution of the EGR valve fresh air amount control.