RU2031239C1 - Starting unit for diesel internal combustion engine - Google Patents

Abstract

FIELD: engine engineering. SUBSTANCE: starting unit has program device 1 whose information input is the input of the unit, actuating relay 2 whose contacts 4 are connected to the unit input used for connecting a battery and to the output of the unit, auto-generator 6, and control logical circuit 5. In addition, the unit can be provided with logical circuit OR 12 whose inputs are connected to the feeding bus of the unit and to the output of the unit. The output of the logical circuit OR is connected to the feeding bus of control logical circuit 5. The contact of the actuating relay is secured to the flat spring and mechanically coupled with the armature of the actuating relay. The output frequency of the auto-generator is equal or multiple to the natural resonance frequency of mechanical oscillation of the movable system of the actuating relay. EFFECT: enhanced reliability. 4 cl, 4 dwg

Description

 The invention relates to the electrical equipment of internal combustion engines, in particular to devices for starting a diesel engine.

 Known devices for starting a diesel engine with glow plugs containing a software device that uses an executive relay to control the current through the glow plugs of a diesel engine according to one program or another.

 A device is known in which the software device first includes the first actuating relay, which supplies the maximum current to the glow plugs with its contact to quickly heat them, and then after a certain period of time switches on the second actuating relay, which reduces the current through the candles to maintain the temperature of the candles at a given level [1].

 A device is known in which a software device maintains the temperature of glow plugs by means of an executive relay by changing the duration of the activation of the actuator relay by a signal from a temperature sensor [2].

 In the ignition system, the software device maintains the temperature of the glow plugs by controlling the resistance of the glow plugs [3].

 The disadvantages of these devices are that they do not provide sufficient reliability of the ignition system due to the low reliability of the Executive relay, the contacts of which switch significant currents (hundreds of amperes).

 There are also known devices for starting a diesel engine containing a software device that controls a non-contact actuator (semiconductor switch, thyristor, etc.) included in the power supply circuit of glow plugs [4].

 The disadvantages of devices with contactless actuators are that the existing proximity switches at currents of 200-300 A have a voltage drop of the order of 1.5-2.0 V, i.e. 300-600 W power dissipated on a proximity switch. This leads to difficulties associated with heat removal, and also reduces the efficiency of use of such elements. In addition, in such devices it is necessary to apply special measures to protect proximity switches from failure in the event of a short circuit in a candle or in lead wires. All this increases the cost of equipment.

 Closest to the invention is a diesel engine starting unit, which contains a software device with an executive relay at the output [5]. The software device generates a signal to turn on the executive relay, the duration of which depends on the temperature of the engine coolant. The contact of the executive relay is included in the power supply circuit of the glow plugs.

 This scheme of the diesel engine starting block is quite simple and economical. However, sticking (welding) of the contacts of the executive relay is possible, as a result of which the current in the circuit of the glow plugs is not interrupted, which can lead to their failure. The spark plug withstands only short-term current transmission. In the case of long-term transmission of maximum current, the spark plug overheats and may collapse, and splinters of the spark plug may get into the engine, which will lead to its failure. The battery of a passenger car can also withstand a load of 200-300 A only in short-term mode, if the relay contacts stick, the battery can fail. At the same time, due to the high currents of the connection of the elements of the ignition system (battery, spark plug, contact of the executive relay), they are designed so that these circuits are not disabled by the "START" key (starter key). Therefore, in the event of a relay failure, the driver must open the power supply circuit for the candles, for example, by disconnecting the battery terminal, which is not possible to perform quickly. Therefore, the task of increasing the reliability of the functioning of the diesel engine starting block is very relevant.

 The aim of the invention is to increase the reliability of the starting block of a diesel engine.

 This is achieved by the fact that the diesel engine starting unit, which contains a software device, the information input of which is the information input of the unit, an executive relay, the contacts of which are connected respectively to the input of the unit, which serves to connect the battery, and to the output of the unit, is additionally equipped with means for modulating the control signal an executive relay and an executive relay control logic, wherein the input of the modulating means for controlling the executive relay is connected to the output of the ka, the output of the control relay control signal modulation means is connected to the first input of the executive relay control logic circuit, the second input of which is connected to the output of the software device, the output of the executive relay control logic circuit is connected to the coil of the executive relay.

 In addition, the control unit for starting the diesel engine can be equipped with an OR logic circuit, the inputs of which are connected respectively to the power supply bus of the unit and to the output of the unit, and the output of the OR logic circuit is connected to the power bus of the executive relay control logic circuit.

 In the control unit for starting the diesel engine, the movable contact of the executive relay is fixed to a flat spring mechanically connected to the armature of the executive relay.

 In the control unit for starting a diesel engine, the frequency of the output signal of the modulation signal of the control signal of the executive relay is equal to or a multiple of the natural resonant frequency of the mechanical oscillating system of the movable part of the executive relay.

 In FIG. 1 shows a diagram of a proposed diesel engine starting block; in FIG. 2 - structural diagram of the Executive relay, which is part of the block; in FIG. 3 - a possible embodiment of a logic circuit for controlling an executive relay; in FIG. 4 is a possible embodiment of a modulation means of a control signal of an executive relay.

 The diesel engine start-up block contains a software device 1, an executive relay 2 with a winding 3 and pin 4, a logic circuit 5 for controlling the executive relay, means 6 for modulating the control signal for the control of the executive relay, information input 7 of the block, pin 8 is an on-board power supply, pin 9 is a bus block power supply, pin 10 - block output, pin 11 (common). In one embodiment, the unit may be equipped with a logic circuit OR 12.

 For the functioning of the unit in the vehicle’s electrical system, the ignition key (“START” key) 13 connected between the contacts 8 and 9 of the unit, the battery 14 connected between the contacts 8 and 11 of the unit, the spark plug 15 connected between the contacts 10 and 11 are connected to it unit, as well as a temperature sensor 16 connected between the contacts 7 and 11 of the unit. Information input 17 of the software device 1 is connected to the information input 7 of the block. The power bus 18 and 19 of the software device 1 are connected respectively to the contacts 9 and 11 of the block. The output 20 of the software device 1 is connected to the input 21 of the logic circuit 5, the second input 22 of which is connected to the output 23 of the means 6. The input 24 of the means 6 is connected to the terminal 10 of the block, the power bus 25 of the means 6 is connected to the terminal 11 of the block.

 The output 26 of the logic circuit 5 is connected to the winding 3 of the relay 2, the second output of the winding 3 is connected to the terminal 8 of the block. Contact 4 of the executive relay 2 is connected between contacts 8 and 10 of the block.

 The power bus 27 ("common") of the logic circuit 5 is connected to the terminal 11 of the block. The structure of the logic circuit 5 may include an autonomous power source (dry battery, miniature battery) connected to the power buses 27 and 28. In one embodiment of the unit, the power bus 28 of the logic circuit 5 can be connected to the output of the logic circuit 12, the inputs of which are In this embodiment, they are connected respectively to the contacts 9 and 10 of the unit.

 The software device 1 can be performed according to one of the known schemes generating an output signal, the duration of which is a function of two parameters - the voltage at the input 18 of the software device 1 and the temperature of the engine coolant (resistance of the temperature sensor 16 connected to the information input 17 of the software device 1) .

 The software device 1 can perform other functions (turning on the heating of diesel fuel, signaling the presence of water in the fuel filter, turning off the glow plugs for the duration of the starter, etc.).

 The relay (see figure 2, a) contains a coil with a core 29 of soft magnetic material, an armature 30 of soft magnetic material, which can rotate around the support 31 and the return spring 32. An anchor 30 is fixed plate 33, made in the form of a flat steel or bronze a spring, at the end of which contact 34 is fixed. The second contact 35 is fixedly mounted on the rack 36.

 The logic circuit 5 for controlling the executive relay contains the logical elements NOT 37.38, the logical element OR NOT 39, resistors 40-43, transistors 44.45.

 The input of the logic element 37 is connected to the input 21 of the logic circuit 5 and through the resistor 40 to the power bus "common". The input of the logic element 38 is connected to the input 22 of the logic circuit 5 and through the resistor 41 - with the power bus "common". The outputs of the logic elements 37, 38 are connected respectively to the first and second input of the logic element 39, the output of which is connected through the resistor 42 to the base of the transistor 44. The emitter of the transistor 44 is connected to the base of the transistor 45 and through the resistor 43 to the common bus to which it is connected also the emitter of the transistor 45. The collectors of the transistors 44, 45 are combined and connected to the output 26 of the logic circuit 5.

 The power circuits of the logic elements 37-39 are connected respectively to the power bus 27 (common) and 28 (plus bus).

 Means 6 modulation of the control signal of the Executive relay can be made in the form of a self-oscillating generator, for example, in the form of a multivibrator (see figure 4). The power bus of the self-oscillating generator is connected respectively to the contacts 24 and 25 of the means 6, and the output of the self-oscillating generator serves as the output 23 of the means 6.

 As a logical circuit OR 12 (see figure 1) can be used a standard diode circuit OR.

 The connection diagram of the unit in the vehicle electrical system is shown in figure 1. When the ignition key 13 is in the "Ignition" position, its contacts are closed and the voltage from the battery 14 through the key 13, terminal 9 enters the input 18 of the software device 1. The input 17 of the software device 1 receives a signal from the temperature sensor 16. The software device 1 generates at the output 20, a logical signal "1", the duration of which depends on the temperature (from the signal of the sensor 16) and on the voltage of the battery. This logical signal is fed to input 21 of the logic circuit 5, which by the output signal on pin 26 turns on the executive relay 2. Pin 4 of relay 2 is closed and the voltage from the battery 14 is connected through pin 8, pin 4, pin 10 to the engine spark plugs 15. The candles warm up, after which the signal lamp (not shown) is turned on, indicating that the engine is ready to start. The driver turns on the starter and spins the engine, which starts. After a certain period of time, the software device 1 generates a signal "0" at the output 20, which is fed to the input 21 of the logic circuit 5. The logic circuit 5 with the output signal at the output 26 turns off the relay 2, contact 4 of which opens, the current through the spark plugs 15 stops.

 In the event that after the signal to turn off the relay (signal "0" at the output 20 of the software device 1), contact 4 does not open (due to sintering of its contacts), the unit operates as follows. At the input 24 of the means 6 from the moment of closing of the contact 4 there is a voltage equal to the voltage of the battery 14. Therefore, the self-generator of the means 6 is excited and at the output 23 of the means 6 there is a signal in the form of periodically repeating rectangular pulses, which is fed to the input 22 of the logic circuit 5. Until while at the input 21 of the logic circuit 5 there is a signal “1” (the relay is on) the pulse signal from input 22 is not transmitted to the output 26 of the logic circuit 5. As soon as the signal “0” appears at the input 21 of the logic circuit 5 (relay 2 should turn off ) them the pulse signal from input 22 enters the output 26 of the logic circuit 5 and modulates the control signal of the executive relay 2. Modulation of the control signal leads to the forced opening of contact 4 of the relay 2, the signal at the input 24 of the means 6 disappears, respectively, the signal at the output 26 of the logic circuit 5 becomes equal zero, the circuit returns to its initial state until the next engine start cycle.

 The described operation algorithm corresponds to the embodiment of the block, in which the logic circuit 5 is powered by an autonomous power source. In the case when the embodiment of the block with the logic circuit 12 is used, the block operates as follows. Logic circuit 5 receives power from the battery 14 through key 13, terminal 9 of the block, first input of logic OR 12, output of logic 12, terminal 28 of logic 5. After turning off key 13, if terminal 4 of the relay does not open, then the logic circuit 5, the battery 14, terminal 8 of the unit, terminal 4 of the relay, second input of the logic circuit 12, the output of the logic circuit 12, terminal 28 of the logic circuit 5 continues to receive power through the circuit. This provides power to the logic circuit 5 after turning off the power supply to the unit (after Addi ctive contact 13) on all the time does not open contact 4 relays.

 The process of forced opening of contacts 4 of relay 2 is as follows (see Fig. 1 and 2). The case is considered when the relay contacts do not open after turning off the current in the relay winding. In this case, the logic circuit 5 generates a modulated signal supplied to the relay coil from the output 26 of the logic circuit 5.

 The dimensions of the relay parts are selected so that at the moment of contact closure 34, 35 between the core 29 and the armature 30 there remains an air gap (see Fig. 2, b). Therefore, after the current enters the relay winding, the armature 30 is attracted to the core 29, the flat spring 33 bends (see Fig. 2, c) and, due to the deflection of the flat spring, occurs at contacts 34.35, a shear force directed along these contacts tends to shift the contact 34 relative to the contact 35. After turning off the control current, the armature 30 under the influence of the return spring 32 rotates around the support 31, the spring 33 bends in the opposite direction relative to the previous state (see figure 2, c, d). This creates a shear force acting along the spring 33 and also directed in the opposite direction relative to the previous state. Repeated exposure of the modulated signal relay coil leads to the repeated occurrence of the situations described in FIG. 2c, d. Ultimately, the shear force biases the contact 34 relative to the contact 35, while the microwelding is destroyed, and the surfaces of the contacts 34 and 35 self-clean due to friction against each other. Thus, the effect of the modulated signal on the relay winding leads to the forced opening of its contacts.

 In the case of welding of contacts 34 and 35 to each other, a mechanical oscillating system is formed, including an armature 30 fixed at one end to a support 31, a spring 33 fixed at one end to an armature and the other on a welded contact 34 to contact 35. If you select a signal modulation frequency control relay equal to or a multiple of the natural frequency of the mechanical vibrations of the mobile system of the relay, the amplitude of the oscillations of the mobile system will increase significantly when exposed to a modulated signal compared to the normal course of the mobile system we. This will lead to an increase in the forces acting on the contacts 34, 35. This increases the likelihood of destruction of the micro-welding of the contacts and increases the reliability of the relay.

 The logic circuit 5 control Executive relay works as follows. When received at the input 21 of the logical signal "1" to turn on the Executive relay, this signal is fed to the input of the logical element 37, the output of which is the signal "0". This signal "0" is input to the logic element 39, the output of which appears the signal "1" regardless of the output signal of the logic element 38 ("0" or "1"). This signal "1" opens the transistors 44, 45, which corresponds to the on state of the Executive relay.

 After the end of the cycle of heating the glow plugs, the software device 1 gives a command to turn off the executive relay, i.e. at the input 21 of the logic circuit 5, the signal "0" appears, which from the output of the logic element 37 in the form of a signal "1" is fed to the first input of the logic element 39. If there is a signal "0" at the input 22 (which corresponds to the signal "1" on the output of logic element 38), two signals "1" act on the inputs of logic element 39, so the signal "0" is generated at the output of this logic element, transistors 44, 45 are closed, which corresponds to the off state of the executive relay.

 In the event that the relay contacts are not opened due to their welding, then at the input 24 of the means 6 (see Figs. 1 and 3), a voltage equal to the voltage at the input of the unit 8 is applied. As a result, a sequence of rectangular pulses appears at the output 23 of the means 6, i.e. the signal at input 22 of logic circuit 5 changes periodically from "0" to "1" and vice versa. At the same frequency, the signal at the output of the logic element 39 changes; accordingly, transistors 44, 45 are periodically closed and opened, which leads to a modulation of the control signal of the executive relay at the output 26 of the logic circuit 5. After opening the relay contacts, the voltage at the input 24 of the means 6 disappears, modulation The control signal of the executive relay stops.

 Means 6 modulation of the control signal of the Executive relay works as follows (see figure 4). The input 24 of the means 6 is connected to the power bus of this device, the second power bus ("common") is connected to the contact 25 of the means 6. When voltage appears at the input 24 of the means 6, the oscillator is excited, and a signal appears in its output as a series of rectangular pulses that arrive the output 23 means 6. After the disappearance of the voltage at the input 24, the self-oscillations break down, the signal at the output 23 of the means 6 stops.

 The advantages of the proposed block are as follows. The presence of a modulation signal for the control signal, as well as a logic circuit for controlling the executive relay, made it possible to control and automatically force open the contacts of the executive relay in case of welding, sticking. This increases the reliability of the unit.

 The proposed embodiment of the block in combination with the proposed design of the mobile system of the executive relay also increases the reliability of the relay due to the occurrence of shear forces acting on the welded relay contacts during the modulation of the relay control signal.

 The use of a modulation signal with a frequency equal to or a multiple of the natural frequency of the mechanical vibrations of the moving relay system allows increasing the contact separation force, as well as providing self-cleaning of the relay contacts, which contributes to the reliability and durability of the unit.

 In practice, a block was implemented according to the proposed scheme and a relay was made, the contacts of which were made of red copper without coating with precious metals, as is usually done to increase the reliability of the relay. In tests, a current of about 300 A was passed through the relay contacts. After 15,000 switching operations, the relay remained operational, and the relay contacts were left without visible damage (burning).

Claims (4)

 1. START-UP DIESEL FOR THE INTERNAL COMBUSTION DIESEL ENGINE, containing a software device connected to the power supply bus of the unit and having an information input that is the information input of the unit, an executive relay, the contact of which is connected between the input of the unit for connecting the battery and the output of the unit, characterized in that it equipped with a self-oscillator and logic control circuit executive relay with two inputs, one of which is connected to the output of the self-oscillator, and the other to the output of the software device, and you od control logic connected to the output relay coil and the oscillator input - with the output of the unit.  2. The block according to claim 1, characterized in that it is additionally equipped with an OR logic circuit, the inputs of which are connected respectively to the power supply bus of the unit and the output of the unit, and the output is connected to the power bus of the control circuit of the executive relay.  3. The block according to claim 1, characterized in that the movable contact of the actuator relay is mounted on a flat spring located with the possibility of interaction with the armature of the actuator relay.  4. The block according to claim 3, characterized in that the oscillator is made at an output frequency equal to or a multiple of the natural resonant frequency of the mechanical vibrations of the mobile system of the executive relay.

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