DC/DC Converter Fuel Injector Control via Dynamic Voltage Threshold
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Solution Overview
Problem
Existing DC/DC voltage converters for fuel injectors in vehicles face inefficiencies due to varying battery voltage, leading to suboptimal power delivery when voltage is low and oversizing when voltage is sufficient, resulting in inefficient capacitor charging and reduced converter performance.
Innovation Solution
A method that measures the battery voltage, determines a threshold current value using a predetermined curve, and actuates a switch to regulate power by adjusting the current through the coil, maintaining stable power delivery around a predetermined value, such as 40 Watts, by compensating for voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the converter is designed to operate at minimum power Pmin, then optimal operation is ensured, but the converter cannot charge the intermediate capacitor optimally when battery voltage is low
Solution Approach 1:
The patent applies dynamics by making the converter's power capability adjustable rather than fixed. The controller dynamically adapts the converter's operating point based on real-time battery voltage measurements, allowing the system to transition between different power levels. This resolves the contradiction by enabling the converter to operate at optimal power when battery voltage is sufficient, and reduce power when battery voltage is low, thereby maintaining both reliable operation and charging capability across varying conditions.
Solution Approach 2:
The patent changes the operating parameters of the converter based on battery voltage. Specifically, the controller adjusts the switching duty cycle and/or frequency of the power electronic components to modify the converter's effective power output. This parameter adaptation allows the system to match its power delivery to the actual battery conditions, ensuring optimal operation at low voltage while maintaining adequate charging capability when voltage is higher.
2Productivity
If the converter is designed with high power capability, then it can charge the capacitor quickly, but the converter becomes oversized and efficiency drops
Solution Approach 1:
The patent applies partial action by having the converter deliver only the necessary power level required by the battery conditions rather than always operating at maximum capability. The controller modulates the power transfer to match actual needs, avoiding the energy losses associated with oversized operation. This allows the system to achieve adequate charging speed when needed while maintaining high efficiency during normal operation by avoiding excessive power transfer.
Solution Approach 2:
The system dynamically adjusts its power transfer rate based on real-time conditions. Rather than being fixed at high power capability, the converter's actual power delivery is continuously adapted to match battery voltage and charging requirements. This dynamic operation eliminates the need for an oversized design, maintaining both adequate charging speed and high efficiency across different operating conditions.
3Speed
If Bang-Bang regulation is used to quickly raise output voltage, then response speed is improved, but power varies significantly with battery voltage causing suboptimal operation
Solution Approach 1:
The patent implements feedback control by continuously monitoring battery voltage and using this information to adjust the converter's operating parameters. The controller measures the actual battery voltage and compares it with reference values, then dynamically adjusts the power transfer and switching characteristics accordingly. This feedback mechanism maintains stable operation across varying voltage conditions while preserving the ability to respond quickly when needed.
Solution Approach 2:
The system transitions from static Bang-Bang regulation to dynamic control that adapts to varying battery conditions. The controller dynamically adjusts switching frequency and duty cycle based on real-time voltage measurements, allowing the system to maintain optimal operation across different voltage levels while preserving fast response capability when rapid voltage adjustment is required.
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 approach ensures consistent power delivery to fuel injectors, optimizing their operation and improving the efficiency of the DC/DC voltage converter by stabilizing power output regardless of battery voltage fluctuations.
Implementation Method 1
The internal working principle of the converter consists in charging a coil with the current supplied by the battery and cutting the current cyclically, using a switch, notably a transistor, for example of the MOS type. When the switch is closed, the coil is charged and when the switch is open, the energy stored in the coil is transferred as a current to the intermediate capacitor in order to recharge it.
Data Source
AI summary
Disclosed is a method for controlling a DC/DC voltage converter for controlling the current of at least one fuel injector of an internal combustion engine of a motor vehicle, the vehicle including a supply battery and the converter including a coil and a switch. The method includes the steps of measuring the value of the voltage delivered by the battery, of determining a threshold value of the current passing through the coil from the measured value of the voltage and from a predetermined curve of the current as a function of the voltage, and of actuating the opening of the switch when the current passing through the coil reaches the determined threshold value of the current in order to regulate the power of the converter.