Boost Switching Device Slew Rate Control for Engine Temperature Management
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Solution Overview
Problem
Existing in-vehicle engine control systems face challenges in accurately managing the temperature of boost switching devices, leading to inefficient fuel injection and increased engine rotational speed limitations due to transient electric power consumption and temperature management issues.
Innovation Solution
An in-vehicle engine control apparatus with a drive control circuit unit, boost control circuit unit, and calculation control circuit unit that includes a microprocessor and program memory to generate fuel injection command signals and determine the number of injections based on environmental temperature, using a slew rate selection circuit to manage current increase rates and reduce temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of split injections is increased to improve fuel efficiency and exhaust gas purification, then the fuel injection control performance is improved, but the temperature increase in the boost switching device becomes excessive
Solution Approach 1:
The patent applies dynamics by making the slew rate of the boost switching device variable rather than fixed. The control device adjusts the slew rate dynamically based on operating conditions such as engine load, rotational speed, and ambient temperature. This allows the system to optimize the balance between injection performance and temperature control in real-time, resolving the contradiction between improved fuel injection control and excessive temperature increase.
Solution Approach 2:
The patent changes the electrical parameter (slew rate) of the boost switching device to control temperature. By adjusting the current rise rate through variable slew rate control, the system modifies the power consumption characteristics and heat generation of the switching device. This parameter change enables the system to maintain effective fuel injection control while preventing excessive temperature rise in the boost switching device during multiple split injections.
2Speed
If the slew rate is increased to improve the response speed of the boost switching device, then the switching speed is improved, but the transient electric power consumption increases
Solution Approach 1:
The patent applies dynamics by implementing variable slew rate control that adapts to different operating conditions. Instead of using a fixed high slew rate that always provides fast switching, the system dynamically adjusts the slew rate based on factors like engine load, rotational speed, and temperature. This allows the system to achieve fast switching when needed while reducing power consumption during conditions where lower switching speeds are acceptable.
Solution Approach 2:
The patent changes the electrical parameter (slew rate) of the boost switching device to control temperature. By adjusting the current rise rate through variable slew rate control, the system modifies the power consumption characteristics and heat generation of the switching device. This parameter change enables the system to maintain effective fuel injection control while preventing excessive temperature rise in the boost switching device during multiple split injections.
3Reliability
If the temperature management is conservative to ensure reliability of the switching device, then the device reliability is maintained, but the engine rotational speed at which split injection can be carried out is limited
Solution Approach 1:
The patent applies dynamics by implementing adaptive slew rate control that responds to real-time operating conditions. The system monitors parameters such as engine load, rotational speed, and ambient temperature, then adjusts the slew rate accordingly. This dynamic approach allows the system to maintain reliable operation at higher rotational speeds by reducing slew rate when temperature becomes excessive, while enabling split injection at lower speeds where higher slew rates can be used safely.
Solution Approach 2:
The patent changes the electrical parameter (slew rate) of the boost switching device to control temperature. By adjusting the current rise rate through variable slew rate control, the system modifies the power consumption characteristics and heat generation of the switching device. This parameter change enables the system to maintain effective fuel injection control while preventing excessive temperature rise in the boost switching device during multiple split injections.
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
This solution allows for accurate temperature management of boost switching devices, reducing transient electric power consumption and enabling higher engine rotational speeds during split injections while minimizing radio noise and maintaining low noise levels.
Implementation Method 1
a boost control circuit unit for generating a boosted high voltage for quickly magnetizing one of the plurality of electromagnetic coils; The boost control circuit unit includes an inductive device to be intermittently magnetized by a boost switching device
Implementation Method 2
to accurately managing the temperature of boost switching devices, leading to inefficient fuel injection and increased engine rotational speed limitations due to transient electric power consumption and temperature management issues
Data Source
AI summary
A boost switching device (115) for generating a boosted high voltage (Vh) includes a slew rate selection circuit (115s), decreases a selection value (k) to suppress noises when the temperature of the boost switching device (115) is low, and increases the selection value (k) to suppress a temperature increase when the temperature thereof is high. An internal average temperature of an in-vehicle engine control apparatus (100) is detected by an environmental temperature detection device (139), reference data (400) provided in a calculation control circuit unit (130) is used to calculate a relationship between a permissible engine rotational speed (Nk) at which the split injection can be continued at a current measured environmental temperature (Tx) and the selection value (k), and an appropriate selection value (k) corresponding to a current engine rotational speed (Ne) is determined.