Fuel Injection Step-Down Circuit Residual Charge Dissipation
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Solution Overview
Problem
The existing fuel injection devices with step-up circuits fail to rapidly dissipate accumulated charge in capacitors after the ignition switch is turned off, posing a safety risk for operators who need to perform maintenance operations within a short time.
Innovation Solution
Incorporating a discharging circuit that rapidly dissipates the residual charge in the step-up circuit after the ignition switch is turned off, and utilizing a step-down circuit to provide a stable power supply for the control computing unit during shutdown and restart operations, especially during idling-stop and low-temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a step-up circuit is used to step up battery voltage for driving the fuel injection valve, then the fuel injection valve can be driven with sufficient voltage, but the accumulated charge in the capacitor cannot be rapidly dissipated after the ignition switch is turned off, posing a safety risk
Solution Approach 1:
The patent converts the harmful residual charge in the capacitor into a beneficial resource by using it to power the shutdown process and idling-stop control. The discharging circuit is configured to discharge the capacitor through the control computing unit, allowing the residual charge to be utilized for controlling the fuel injection valve during shutdown and restart operations, thereby eliminating the safety risk while maintaining functional utility.
2Reliability
If the ignition switch is turned off to stop the engine, then the power supply is interrupted, but the accumulated charge in the capacitor remains for several tens of minutes, preventing immediate maintenance operations
Solution Approach 1:
The patent implements preliminary action by automatically initiating the discharging process through the discharging circuit as soon as the ignition switch is turned off. The control computing unit is configured to control the discharging circuit to rapidly discharge the capacitor, which prepares the system for immediate maintenance operations by eliminating the residual charge hazard before the operator needs to perform maintenance, thereby reducing the waiting time.
3Object-affected harmful factors
If a discharging circuit is added to rapidly dissipate residual charge, then operator safety is enhanced, but the device complexity increases
Solution Approach 1:
The patent applies multi-functionality by designing the discharging circuit to serve multiple purposes: it rapidly dissipates residual charge to ensure operator safety, powers the shutdown process after ignition is turned off, and provides power during idling-stop operations. The control computing unit integrates the discharging function with the existing control logic, allowing a single circuit to address multiple needs without proportionally increasing device complexity.
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
Enhances operator safety by ensuring rapid dissipation of capacitor charge and provides a stable power supply to prevent control unit instability during engine restarts and low-temperature starts, effectively utilizing the residual charge while ensuring safe and reliable operation.
Implementation Method 1
a step-up circuit that is connected to the battery and steps up a battery output voltage to output a stepped-up voltage
Implementation Method 2
a discharging circuit that is connected to an output side of the step-up circuit and causes residual charge in the step-up circuit to be rapidly dissipated
Implementation Method 3
a capacitor of a step-up circuit is applied with a voltage of around 40 V, for example, and charge is accumulated therein
Data Source
AI summary
A step-down circuit is connected to an output of a step-up circuit that steps up a battery voltage, and an output of the step-down circuit is connected to a power supply input terminal of a CPU via an FET. The step-down circuit is normally maintained in an inactive state and, in response to an ignition switch being turned off, the CPU causes the step-down circuit to actuate and a stepped-down voltage (equal to a stabilized voltage) is output from the step-down circuit. The stepped-down voltage is further stepped down to a CPU power supply voltage, and the CPU power supply voltage is supplied to the power supply input terminal of the CPU. This allows the residual charge of the step-up circuit to be dissipated by the step-down circuit and the CPU.