Voltage Boost Circuit Overboost Protection for Engine Injectors
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Solution Overview
Problem
Internal combustion engine controllers for direct injection systems face challenges in managing overboost states, which can lead to circuit damage and inefficiencies due to current regeneration during boost operations, particularly in engines with multiple cylinders and complex voltage boost patterns.
Innovation Solution
The controller incorporates a voltage boost circuit with a discharge switching element in parallel to the charging diode, allowing excess energy to be safely discharged into the battery power supply when the boost voltage exceeds a set threshold, and includes a control circuit for managing overboost compensation and voltage boost control, minimizing heat generation and component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If current regeneration is used to reduce heat in the driving circuit, then heat generation is suppressed, but boost voltage may overstep the set voltage range and enter an overboost state causing circuit damage
Solution Approach 1:
A discharge switching element is introduced as an intermediary component between the boost capacitor and battery power supply. This mediator provides a controlled path for excess energy discharge, preventing overboost conditions while enabling current regeneration for heat suppression. The discharge switching element acts as a safety valve that activates when boost voltage exceeds the threshold, thereby resolving the contradiction between heat management and voltage stability.
2Reliability
If a discharge switching element is added to prevent overboost states, then circuit reliability is improved, but device complexity increases
Solution Approach 1:
The discharge switching element is integrated into the existing boost circuit architecture, merging the overboost protection function with the current regeneration pathway. Rather than adding a completely separate protection system, the discharge switching element shares the circuit topology with the charging diode and battery power supply, thereby reducing overall system complexity while achieving reliable overboost protection.
3Productivity
If boost voltage is increased to improve injector control and fuel injection performance, then engine output and fuel efficiency are improved, but thermal energy conversion losses increase
Solution Approach 1:
The patent converts the harmful thermal energy that would normally be lost during voltage boosting into a beneficial resource. By implementing current regeneration that feeds back to the boost capacitor, the system recovers energy that would otherwise be dissipated as heat. The discharge switching element enables controlled energy release when needed, transforming potential energy losses into useful work that maintains boost voltage within optimal ranges for injector performance.
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 effectively prevents thermal damage and noise issues, allows for efficient energy regeneration, and maintains the boost voltage within a safe range, enhancing the reliability and efficiency of the engine controller.
Implementation Method 1
a voltage boost circuit (100) that supplies a switching current from a battery power supply voltage to a boost coil (101) and stores, into a boost capacitor (111), a high voltage generated in the boost coil (101)
Implementation Method 2
through a charging diode (110-1), electrical energy of a load device is made to disappear and a high voltage generated in the boost coil (101) is stored into a boost capacitor (111)
Implementation Method 3
the discharge switching element (110-2) is made on, so that the high voltage stored within the boost circuit is discharged into the battery power supply through the boost coil (101)
Data Source
AI summary
The present invention is to compensate for an overboost state of a voltage boost circuit 100 in such a form as to suit conditions for driving an injector 3 for an internal combustion engine, to prevent damage to the boost circuit 100 if overboost compensation and boosting simultaneously occur, and to minimize the amount of heat, the number of components required, noise, and the like. This invention is constructed so that in a voltage boost circuit 100 for driving a fuel injector 3 of an internal combustion engine by supplying a switching current from a battery power supply voltage to a voltage boost coil 101 and storing into a voltage boost capacitor 111 through a charging diode 110-1 a high voltage generated when the switching current is cut off: if regeneration of an injector current 3A results in a boost voltage 100A higher than an overboost compensation starting voltage 403, the high voltage developed in the voltage boost coil 101 will be discharged into the battery power supply 1 through the boost coil 101 by electrically energizing a discharge switching element 110-2 provided in parallel to the charging diode 110-1; and if the overboost compensation overlaps a boost execution period, an end of the boost execution period will be awaited until the overboost compensation is started.