High-Pressure Pump Solenoid Current Return Path to Cut Diode Heat
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Solution Overview
Problem
Injection control devices for high pressure pumps in internal combustion engines experience significant heat loss due to return currents flowing through reflux diodes, which affects their design and operation.
Innovation Solution
The injection control device employs a configuration where transistors Q1 and Q2 are controlled to manage the solenoid current, ensuring that return currents flow through transistor Q2 instead of the reflux diode, minimizing heat loss by preventing substantial forward current flow through the diode D2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If return current flows through the reflux diode, then the solenoid can be controlled, but significant heat loss occurs in the diode
Solution Approach 1:
The patent introduces a second transistor (Q2) as an intermediary component to handle the return current. Instead of the return current flowing directly through the reflux diode (D2), it now flows through transistor Q2 which has lower forward voltage. This mediator component resolves the contradiction by providing an alternative current path that maintains solenoid control functionality while significantly reducing heat loss in the diode.
Solution Approach 2:
The patent replaces the diode-based current return path with a transistor-based switching mechanism. By using transistor Q2 to control and conduct the return current, the system substitutes the passive diode conduction with an active transistor switching system, achieving lower voltage drop and reduced heat loss while maintaining precise solenoid control.
2Power
If larger engines with higher current demands are used, then engine performance is improved, but heat loss in the injection control device increases
Solution Approach 1:
The second transistor Q2 serves as an intermediary that handles the high return currents required by larger engines. By routing return currents through Q2 instead of the diode, the system can support higher engine power demands while minimizing the heat loss that would otherwise increase proportionally with the current magnitude.
Solution Approach 2:
The patent changes the electrical parameters of the current path by introducing a transistor with lower forward voltage characteristics. This parameter change allows the system to handle higher currents (required for larger engines) with reduced voltage drop and consequently reduced power loss, enabling high-performance engine operation with improved efficiency.
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 configuration significantly reduces heat loss, particularly in larger engines with higher current demands, by directing return currents through the transistor Q2, which has lower heat loss compared to the reflux diode, thereby improving the device's efficiency and performance.
Implementation Method 1
return currents flow through transistor Q2 instead of the reflux diode
Implementation Method 2
The switching elements used to realize such solenoid operations may cause both a forward current to flow through the solenoid and a return current to flow from the solenoid
Data Source
AI summary
An injection control device controls a drive of a solenoid in a high pressure pump for pressurizing fuel to an internal combustion engine. The injection control device includes a transistor on an upstream side of a power supply path from a direct current power supply line to the solenoid and a transistor provided on a downstream side of the power supply path. The injection control device further includes a diode at a position between an upstream terminal of the solenoid and ground, a transistor arranged in parallel with the diode, and a drive controller. The drive controller drives the solenoid to an open position by switching ON the transistors on the upstream and downstream sides of the power supply path.