CN101424222A - Self-lifting high-pressure generating circuit for engine fuel injection control solenoid valve - Google Patents

Abstract

The invention designs a bootstrapping high-voltage generating circuit for a fuel injection control electromagnetic valve of an engine, and is particularly suitable for a high-voltage boosting circuit of an electronic fuel injection control system of a diesel engine. An electromagnet of a high-speed power electromagnetic valve in the electronically controlled fuel injection system of the diesel engine is used as an energy storage inductor for boosting high voltage, an electronic control unit of the diesel engine for driving a switching circuit of the electromagnetic valve is used as a switch of a high-voltage boosting circuit, the principle of time-shared control of a multi-cylinder diesel engine is used, and the electromagnet of an air cylinder at different oil injection time intervals is used for alternately electrifying and shutting the energy storage inductor in certain time sequence through software design of the electronic control unit of the diesel engine to form 'self-induction' high voltage, namely the bootstrapping high-voltage generating circuit. The bootstrapping high-voltage generating circuit has the advantages that the bootstrapping high-voltage generating circuit saves an inductor, a power switching tube and a pulse control circuit in the prior high-voltage boosting circuit, simplifies the high-voltage boosting circuit of the electronically controlled unit in the electronically controlled fuel injection system of the prior diesel engine, reduces cost, and is suitable for any engine needing high-voltage fuel injection.

Description

Self-lifting high-pressure generating circuit for engine fuel injection control solenoid valve

Technical field

The present invention is used for the drive circuit of electronic engine management system fuel injection control high-speed electromagnetic valve, is specially adapted to the charge pumping circuit of diesel engine electronic fuel injection control systems.

Background technique

In the diesel electric-controlled fuel injection system, use the high-speed power electromagnetic valve high pressure fuel injection moment and emitted dose usually.For solenoid valve is opened fast, the lifting power supply of the several multikilowatt pulse energies of providing of diesel engine battery tension is provided in one of technical employing, that is the high drive power supply.After solenoid valve is opened, keep the opening state of solenoid valve by battery feed, until pressing the order fulfillment oil spout.

Up to now, industry-wide adoption be that " inductor-capacitor-switch " circuit produces and drives the required high pressure of high-speed electromagnetic valve, this just needs a pulse generating circuit and the capacitor energy storage circuit with the inductor of certain stored energy, a power switch pipe, a feedback controllable duty ratio with voltage.

Summary of the invention

The invention provides a kind of self-lifting high-pressure generating circuit for engine fuel injection control solenoid valve, simplify the charge pumping circuit of ECU (Electrical Control Unit) in the conventional engines electric control fuel oil jet system.The present invention utilizes the electromagnet of diesel electric-controlled fuel injection system high speed power electromagnet valve as the energy storage inductor that promotes high pressure, utilize the switch of the switching circuit of electronic Control for Diesel Engine unit drives solenoid valve as charge pumping circuit, utilize the principle of multi-cylinder diesel engine timesharing control, software design by engine electronic control unit, to form self-induction high pressure, i.e. " bootstrapping " charge pumping circuit by certain time sequence as inductance alternate energisation and shutoff at the electromagnet of different oil spout period cylinder.

The invention has the advantages that: saved inductor, power switch pipe and pulse control circuit in the conventional high-tension lifting circuit, simplified the charge pumping circuit of ECU (Electrical Control Unit) in the conventional diesel engine electric control fuel oil jet system, reduced cost.

Description of drawings

Fig. 1 self-lifting high-pressure promotes circuit theory diagrams

V _h-lifting high-voltage power, V _b-motor battery feed, L1, L2, each cylinder fuel injection control electromagnet of Ln-diesel engine, K1-control oil spout electromagnet is connected the high-side switch of high pressure, the low-side switch of K2-control oil spout electromagnet ground connection, D1-provides the diode of battery feed to electromagnet, the D2-low-side switch provides electromagnet afterflow passage and produces the self-induction high pressure to the high-voltage power makeup energy when turn-offing, C-high-voltage power storage capacitor, Z-Zener diode restriction high-pressure peak, R1, the R2-divider resistance, the P point provides the high tension voltage signal with control inductance pulse energy to the engine electric-controlled unit processor.

Fig. 2 self-lifting high-pressure promotes circuit control sequential chart

CLD-cylinder oil spout sequential, numeral cylinder number in the sequential, this figure is an example with 6 Cylinder engines, CLD1, CLD2...CLD6 represent the 1st cylinder, the 2nd cylinder respectively ... the 6th cylinder; The pulse width modulated drive signal of PWM-control oil spout.

Embodiment

High pressure produces basic principle:

In circuit shown in Figure 1, when low-side switch K2 was closed, high-side switch K1 was also closed simultaneously, and this moment is by high-voltage power V _hTo oil spout control electromagnet L power supply, electric current among the L is risen so that the electromagnet quick pick-up rapidly, this electric current claims " inrush current ", is designated as I _hWhen electromagnetic actuation, high-side switch disconnects, and to electromagnet L powered by diode D1 by storage battery this moment, low-side switch continues to do pulse-width modulation type PWM conducting, L is last produce one less but be enough to make electromagnet to keep the electric current of attracting state, this electric current claims " keeping electric current ", is designated as Im.When fuel feeding finishes the K2 disconnection, can produce a self induction electromotive force on the electromagnet L, this electromotive force size disconnects the size of current that flows through on the preceding L with K2 and is directly proportional, and this electromotive force and battery tension stack are after diode D1 to storage capacitor C charging, finishes the process that a sub-high pressure produces thus.Too high when the high-pressure energy that produces, Zener diode makes the voltage of high-voltage power supply Vh clamper in regulation with conducting.Because the inrush current during the high-side switch conducting on the L is normally kept the several times of electric current, therefore, the energy shortage that when the electric current shutoff is kept in utilization high-voltage power supply is replenished makes high-voltage power supply keep stable energy balance to reach, must be stable to the high-voltage power supply makeup energy with sustaining voltage by multiple switching operation to L, its conducting electric current of such operation must be less than the critical current of electromagnet oil spout adhesive, to prevent the mistake oil spout, this electric current becomes " complementary energy electric current ", is designated as I _cIf ignore variation inductance in the electromagnetic actuation process, then complementary energy size of current and number of times are determined by following energy balance relations:

$\∫I_h^2\left(t\right)\mathrm{dt}={\∫I}_m^2\left(t\right)\mathrm{dt}+\mathrm{\Σ}{\∫I}_c^2\left(t\right)\mathrm{dt}---\left(1\right)$

The practical application of multicylinder engine:

Because the sensibility reciprocal of electromagnet is bigger, when high engine speeds is moved, single injection electromagnet often is not enough to provide electromagnet as the complementary energy number of times of inductance to high-voltage power supply in the time of non-oil spout period, the complementary energy time that will utilize the multicylinder engine working timing figure to come rational distribution respectively to spray electromagnet like this.Fig. 2 shows the high pressure generation sequential relationship of one 6 Cylinder engine.

In the actual diesel engine fuel injection control circuit, for saving device, the electromagnet that is not each control oil spout is with independently a high-side switch and a low-side switch, but high-side switch is divided into some groups by the fire ignition sequence of motor, every group of shared high-side switch, low-side switch be one of each electromagnet then.The example of 6 Cylinder engines is 1,2, No. 3 shared high-side switch of cylinder among Fig. 2,4,5, No. 6 shared another high-side switch of cylinder.When electromagnet was used as the complementary energy inductance, its ON time must be avoided the time period of this group high-side switch conducting, otherwise will draw the energy of high-voltage power supply.In this example, each electromagnet common property is given birth to 3 sub-high pressure energy: end of injection is kept high-pressure energy that electric current produces and twice chronologically to the complementary energy of other cylinder oil spout electromagnet, before wherein once occurring in high-side switch and opening with guarantee high-side switch open before high-voltage power supply be in voltage rating, claim " preposition complementary energy "; Another time occurs in the process that high-side switch opens that energy discharges the voltage drop that causes when opening back high-voltage power supply capacitor discharge because of high-side switch to replenish, and is called " process complementary energy ".Among Fig. 2, the injection electromagnet high-pressure energy of No. 1 cylinder is carried out preposition complementary energy by No. 3 cylinders, and No. 4 cylinder carries out the process complementary energy.The effect of other cylinder by that analogy.

If once " preposition complementary energy " and once " process complementary energy " be not enough to satisfy the demand in stable high voltage source, then can be with the electromagnet of different cylinders according to each oil supply cylinder sequential, carry out repeatedly complementary energy avoiding having two above low-side switch to open simultaneously under the principle of (overlapping conducting) when high-side switch is opened.This process is carried out automatically by the microprocessor follow procedure of engine electronic control unit.

This example is to describe with 6 Cylinder engines, but the present invention is not limited to this, can be generalized to the motor of other cylinder number according to this.The motor that the present invention censured is that example is illustrated with the diesel engine, but is not limited to diesel engine, can be any motor that needs high voltage fuel to spray.

Claims (4)

1. self-lifting high-pressure generating circuit for engine fuel injection control solenoid valve, it is characterized in that electromagnet with injection electromagnetic valve is as self-induction high pressure generation inductance element, diode D1 is as unidirectional element, diode D2 is as the high pressure coupling element, semiconductor switch pipe K1 is as the high-side switch element, semiconductor switch pipe K2 is as the low-side switch element, and capacitor C is as the high-voltage energy storage element, and Zener diode Z is as high-voltage power supply voltage clamp bit unit.

2. self-lifting high-pressure generating circuit for engine fuel injection control solenoid valve according to claim 1, the electromagnet that it is characterized in that injection electromagnetic valve has dual functions, carry out the fuel-injected major function except itself driving injection valve, utilize spray the self-induction high pressure that produces when finishing to turn-off electromagnet with and do not carry out the fuel-injected time period and produce high pressure as inductance switch.

3. self-lifting high-pressure generating circuit for engine fuel injection control solenoid valve according to claim 1, the unidirectional on state characteristic that it is characterized in that diode D1, stop when high-side switch K1 is closed high-voltage power supply to the storage battery reverse irrigated current, turn-off and provide to electromagnet during low-side switch K2 continuation conducting at high-side switch K1 simultaneously and keep electric current.

4. self-lifting high-pressure generating circuit for engine fuel injection control solenoid valve according to claim 1, it is characterized in that employed engine electronic control unit is applicable to following (containing 6 cylinders) gas of any 6 cylinders or liquid fuel motor electronic control system, for the above motor of 6 cylinders, can dispose plural electronic control unit by the cylinder number, connect the back operation by the communication interface circuit module.

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