High-Pressure Fuel Injector Control Without Step-Up Circuit
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Solution Overview
Problem
High-pressure fuel injectors require a separate and expensive voltage step-up circuit for control, which increases bulk and cost, and there is no existing control means that does not rely on such a circuit.
Innovation Solution
A method for controlling high-pressure fuel injectors using a control means with transistors and diodes that generates and regulates currents without a separate voltage step-up circuit, by charging and discharging an inductance to manage the solenoid current, mimicking the operation of a voltage step-up circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a separate voltage step-up circuit is used to generate the PEAK current for opening the injector needle, then the required current strength is achieved, but the bulk and cost of the control system increase substantially
Solution Approach 1:
The patent merges the voltage step-up circuit functionality directly into the control means by integrating an inductance and switching transistors (first, second, and third transistors) with the solenoid control circuitry. This combination allows the control means to generate the high PEAK current internally without requiring a separate external voltage step-up circuit, thereby reducing overall system bulk and cost while maintaining the capability to deliver sufficient current to open the injector needle.
2Reliability
If the solenoid is supplied with high current to open the needle, then the injector opens effectively, but energy consumption increases
Solution Approach 1:
The patent employs periodic switching of the transistors to charge and discharge the inductance in controlled cycles. The first transistor charges the inductance during off-periods, building up magnetic energy, while the second and third transistors discharge it during injection events to deliver the PEAK current. This periodic action allows energy to be stored and released efficiently, providing high current when needed while consuming less energy during non-injection periods compared to continuous high current supply.
Solution Approach 2:
The patent changes the electrical parameters dynamically by switching between different transistor states. During charging, the circuit operates in an inductive energy storage mode with the first transistor on. During discharge/injection, the circuit transitions to a high-current delivery mode with the second and third transistors activated. This parameter change allows the system to adapt energy consumption to actual injection requirements, consuming high energy only when needle opening 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
Enables efficient generation and regulation of currents for the injector without the need for a separate voltage step-up circuit, reducing bulk and cost while maintaining effective control over the injector's operating phases.
Implementation Method 1
a current is passed through the solenoid with sufficient strength to generate a magnetic force greater than the return force of the spring
Implementation Method 2
charging and discharging an inductance to manage the solenoid current, mimicking the operation of a voltage step-up circuit
Data Source
AI summary
Disclosed is a method for controlling a fuel injector provided with a solenoid for actuating a needle which opens the injector and with a spring for returning the needle to the closed position. The solenoid is supplied with power by a controller including a first potential and a second potential, a first diode and a second diode, a first transistor, a second and a third transistor which is controlled so as to generate various currents using the potentials.