Disclosure of Invention
The invention aims to provide an automatic engine starting control device and method which are simple in structure, high in reliability and easy to implement, and are suitable for an engine provided with an electrically started starter. The starting of the engine is accurately controlled by timely controlling the connection and disconnection of the starter through detecting the rotating speed of the engine, so that the starting automation degree of the engine is improved.
The invention is realized by the following steps: an automatic engine start control device, comprising: the device comprises a power supply voltage stabilizing unit (1), a rotating speed conditioning unit (2), a starting frequency control unit (3), a starting time control unit (4), a starting time coordination unit (5), a driving unit (6) and an execution and indication unit (7);
the power supply voltage stabilizing unit (1) provides stable working voltage for each unit and is electrically connected with each unit;
the rotating speed conditioning unit (2) is electrically connected with the power supply voltage stabilizing unit (1) and the starting frequency control unit (3);
the starting frequency control unit (3) is electrically connected with the power supply voltage stabilizing unit (1), the rotating speed conditioning unit (2) and the starting time control unit (4);
the starting time control unit (4) is electrically connected with the power supply voltage stabilizing unit (1), the starting frequency control unit (3), the starting time coordination unit (5) and the driving unit (6);
the starting time coordination unit (5) is electrically connected with the power supply voltage stabilization unit (1) and the starting time control unit (4);
the driving unit (6) is electrically connected with the power supply voltage stabilizing unit (1), the starting time control unit (4) and the execution and indication unit (7);
the execution and indication unit (7) is electrically connected with the power supply voltage stabilization unit (1) and the driving unit (6).
The method for configuring the parameters of each element of the automatic engine starting control device comprises the following steps:
step 1, the principle of determining the starting time control units R10-R13 is as follows: r10 > R11 > R12;
step 2, calculating a change value of a non-inverting input end of U3B;
step 3, the method for determining R8 and R9 by the starting time coordination unit is as follows: according to the required precharge value of the capacitor C7, the formula R9/(R8 + R9) -0.6 < V5LDetermining R8, R9;
step 4, determining C7 and R14 of a starting time control unit according to the working time Ta of the starter on power supply each time specified by the product technical specification, wherein the method comprises the following steps: from V by C75LCharging to V5HCalculating the time constant and then selecting the appropriate C7 and R14 values from the series of values;
step 5, determining R15 of the starting time control unit according to the interval time Tb after each starter is powered on, C7 and R14 specified by the product technical specification, wherein the method comprises the following steps: from V by C75HDischarge to V5LCalculating a time constant, then calculating R15, and selecting an appropriate R15 value from the series of values;
step 6, the method selected by the starting time control units R6 and R7 is as follows: r7 is more than or equal to 3 multiplied by R6, and the voltage V on R7 is calculatedR7;
Step 7, determining R5 and C6 of the starting number control unit according to the starting number n, wherein the method comprises the following steps: c6 charging from 0 to VR7nTa + (n-1) Tb-n (Ta + Tb), and charged from 0 to V by C6R7Time T, and then select the appropriate C6 and R5 values from the series of values.
The invention has the advantages and effects that:
(1) the starting device can timely control the connection and disconnection of the starter, so that the starting of the engine is accurately controlled, multiple times of automatic starting can be realized, the starting time and the interval time can be different, and the automation degree of the starting of the engine is improved.
(2) The device is composed of hardware, does not need programming, is easy to manufacture, simple to operate, low in cost and excellent in performance, and is suitable for engines equipped with starters.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Referring to fig. 1, the automatic engine starting control device includes a power supply voltage stabilizing unit (1), a rotational speed conditioning unit (2), a starting frequency control unit (3), a starting time control unit (4), a starting time coordination unit (5), a driving unit (6), and an execution and indication unit (7); the power supply voltage stabilizing unit (1) provides stable working voltage for each unit and is electrically connected with each unit; the rotating speed conditioning unit (2) is electrically connected with the power supply voltage stabilizing unit (1) and the starting frequency control unit (3); the starting frequency control unit (3) is electrically connected with the power supply voltage stabilizing unit (1), the rotating speed conditioning unit (2) and the starting time control unit (4); the starting time control unit (4) is electrically connected with the power supply voltage stabilizing unit (1), the starting frequency control unit (3), the starting time coordination unit (5) and the driving unit (6); the starting time coordination unit (5) is electrically connected with the power supply voltage stabilization unit (1) and the starting time control unit (4); the driving unit (6) is electrically connected with the power supply voltage stabilizing unit (1), the starting time control unit (4) and the execution and indication unit (7); the execution and indication unit (7) is electrically connected with the power supply voltage stabilization unit (1) and the driving unit (6).
With further reference to fig. 2, the power supply voltage stabilizing unit includes a starter battery BT1, a switch S1, capacitors C1, C2, and a voltage stabilizing integrated circuit U1; the model of U1 is LM 7809; after the switch S1 is closed, the voltage of the starter battery is input from the 1 st pin, and the VCC voltage of 9V is output from the 3 rd pin for other units. The light emitting diode LED1 is used for power indication, and the resistor R1 is a current limiting resistor of the LED 1.
The rotating speed conditioning unit comprises a rotating speed sensor Sen1, an integrated circuit U2, capacitors C3 and C4, resistors R2, R3 and R4 and a potentiometer RP1, wherein the rotating speed sensor Sen1 is installed near the flywheel of the engine; sen1 uses a variable reluctance type or magnetoelectric type rotation speed sensor, and can also use an eddy current type or hall type rotation speed sensor; the U2 is LM2907M-8 or LM2907N-8, and the signal of the rotating speed sensor is converted into a switching value signal through a charge pump in the integrated circuit.
The connection method comprises the following steps: the 1 st pin of the U2 is connected with an output signal of a rotating speed sensor Sen 1; the 2 nd pin of U2 is connected to one end of a capacitor C3, and the other end of C3 is connected to GND; the 3 rd pin of the U2 is connected to the anode of the capacitor C4 and one end of the resistor R2, and the cathode of the C4 and the other end of the resistor R2 are connected to GND; pins 5 and 6 of U2 are connected to a power supply VCC; pin 8 of U2 is connected to GND. A 4 th pin of the U2 outputs a switching value signal Vrs as a signal for judging whether the starting of the engine is successful or not; one end of the resistor R3 is connected to the 4 th pin of the U2, and the other end of the resistor R3 is connected to GND;
after the resistor R4 is connected with the potentiometer RP1 in series, one end of the resistor R4 is connected to a power supply VCC, and the other end of the resistor R4 is connected to GND; an adjustable center head of RP1 is connected to the 7 th pin of U2, and RP1 is used for adjusting the threshold value of the high and low rotating speed of the output switching value signal Vrs, when the rotating speed is high, the engine is indicated to be started successfully, and when the Vrs outputs high level.
Referring to fig. 3, the start-up number control unit includes a capacitor C6, a resistor R5, R6, R7, a diode VD1, a diode VD2, a diode VD3, and an operational amplifier U3A; the integrated circuit U3 uses a high-voltage rail-to-rail operational amplifier, the model is SGM8272, and the integrated circuit U3 internally contains 2 rail-to-rail operational amplifier units; the total time allowed for the engine starting process, including the total time between each starter turn on and interval, is determined by capacitor C6 and resistor R5, typically in terms of three auto-starts.
The connection method comprises the following steps: a switching value signal Vrs which marks whether the engine starting is successful is connected to the anode of the VD 1; the cathode of the VD1, the anode of the VD2, the anode of the C6 and one end of the R5 are connected to the 3 rd pin of the U3, namely the non-inverting input end of the U3A; the cathode of the C6 is connected to GND, the cathode of the VD2 and the other end of the R5 are connected to VCC; the resistors R6 and R7 are connected in series and then connected between VCC and GND to form a voltage division circuit, and the divided voltage on R7 is connected to the 2 nd pin of U3, namely the inverting input end of U3A; the 8 th pin of U3 is connected to VCC, the 4 th pin is connected to GND, and the output signal of the 1 st pin is connected to the anode of VD 3.
The starting time control unit comprises an integrated circuit U3B, a capacitor C7, resistors R10-R15, a diode VD5 and a diode VD 6; the on time and the interval time of the starter at each time are determined by a capacitor C7, resistors R10-R15 and diodes VD5 and VD 6; the VD5 is added, so that the variation amplitude of the 5 th pin of the U3 meets the design requirement, and output abnormity is avoided when the parameter configuration is improper; the diode VD6 and the resistor R15 have the function of enabling the on time and the interval time of the starter to be unequal, and the interval time is larger than the on and electrifying time, so that the actual condition of starting the engine is met.
The connection method comprises the following steps: the resistors R10 and R11 are connected in series between VCC and GND to form a voltage dividing circuit, R10 is connected with VCC, R11 is connected with GND, and the joint of R10 and R11 is connected with the 5 th pin of U3, namely the non-inverting input end of U3B;
the resistor R13 is connected with the diode VD5 in parallel, and one end of the anode of the VD5 is connected to the 7 th pin of the U3; one end of a VD5 cathode is connected to one end of a resistor R12, and the other end of R12 is connected to the 5 th pin of U3;
the resistor R15 is connected with the diode VD6 in parallel, and one end of the anode of the VD6 is connected to the 7 th pin of the U3; one end of a cathode of the VD6 is connected to one end of a resistor R14, and the other end of the R14 is connected to a 6 th pin of the U3, namely an inverting input end of the U3B in common with an anode of the capacitor C7, a cathode of the diode VD3 and a cathode of the diode VD 4.
The starting time coordination unit comprises resistors R8 and R9 and a diode VD 4; when the starter is turned on for the first time after the switch S1 is closed, the capacitor C7 is quickly precharged, so that the difference between the starting time for the first time and the starting time for the later times is obviously shortened, and the starting time for the first time and the starting time for the later times are close to the same time.
The connection method comprises the following steps: the resistors R8 and R9 are connected in series between VCC and GND to form a voltage dividing circuit, R8 is connected with VCC, R9 is connected with GND, and the joint of R8 and R9 is connected with the anode of VD 4.
The driving unit comprises a MOSFET field effect transistor V1, and the connection method comprises the following steps: the gate of V1 is connected to the 7 th pin of U3, and the source of V1 is connected to GND.
The execution and indication unit comprises a coil of the relay KJ1 and a normally open contact KJ1-1 thereof, a diode VD7, a resistor R16 and a light emitting diode LED 2; the connection method comprises the following steps: one end of a coil of the relay KJ1 is connected to a power supply VCC, the other end of the coil of the relay KJ1 is connected to the drain electrode of the field-effect tube V1, the diode VD7 is connected with the coil of the relay KJ1 in parallel, and the cathode of the VD7 is connected with the power supply VCC; the light emitting diode LED2 is connected in series with the current limiting resistor R16 and then connected in parallel with the coil of the relay KJ1, and the cathode of the LED2 is connected with the drain electrode of the field effect transistor V1; AN electrically started manual button AN1 of the engine is connected in parallel with a normally open contact KJ1-1 of a relay KJ 1; when the KJ1-1 contact is closed, the starter is powered on to perform the task of starting the engine.
The working principle is as follows: after the switch S1 is turned on, the initial rotation speed of the engine is 0, Vrs is low level, VD1 is cut off, a capacitor C6 is charged through R5, the initial voltage on C6 is low, the potential of a No. 2 pin of U3 is higher than that of a No. 3 pin, the No. 1 pin outputs low level, and a diode VD3 is cut off; after the resistors R8 and R9 are subjected to voltage division, the capacitor C7 is quickly precharged through the diode VD4, and the VD4 is cut off after the precharging is completed; initially, the potential of a 6 th pin of the U3 is lower than that of a 5 th pin, the 7 th pin outputs high level, the field effect transistor V1 is in saturated conduction, a coil of the relay KJ1 is electrified to work, a normally open contact KJ1-1 is closed, a starter power supply is switched on, the engine starts, and at the moment, the light emitting diode LED2 is lightened;
along with the rise of the charging voltage of the C7, when the potential of the 6 th pin of the U3 is higher than that of the 5 th pin, the 7 th pin outputs low level, the field effect transistor V1 is cut off, the coil of the relay KJ1 loses power, the normally open contact KJ1-1 is disconnected, the power supply of the starter is disconnected, the 1 st starting of the engine is completed, and the LED2 is turned off;
when the output state of the U3B is inverted, the potential of the 5 th pin of the U3 jumps, after the output of the 7 th pin of the U3 changes from high level to low level, the potential of the 5 th pin of the U3 is reduced, meanwhile, the capacitor C7 starts to discharge through the resistors R14 and R15, the diode VD6 is cut off during discharging, the discharging time constant is greater than the charging time constant, and therefore, the power-on time of the starter is less than the interval time;
along with the reduction of the discharge voltage of the C7, when the potential of the 6 th pin of the U3 is lower than that of the 5 th pin again, the 7 th pin outputs high level again, the field effect transistor V1 is in saturated conduction, the coil of the relay KJ1 is electrified to work, the normally open contact KJ1-1 is closed, the power supply of the starter is switched on again, the engine starts to be started for the 2 nd time, and the LED2 is lightened;
during relay action, if the engine start is unsuccessful, the engine speed will not reach the threshold set by RP1, and therefore pin 7 of U3 will cycle high and low continuously, and the starter will start repeatedly.
If the engine is successfully started during the action of the relay, the rotating speed of the engine exceeds a threshold value set by RP1, Vrs output by the rotating speed conditioning unit is at a high level, a diode VD1 is conducted, the voltage on C6 is kept at the high level, the potential of a No. 3 pin of U3 is higher than that of a No. 2 pin, the No. 1 pin outputs the high level, a diode VD3 is conducted and outputs the high level, the potential of a No. 6 pin of U3 is always higher than that of a No. 5 pin, the No. 7 pin outputs the low level, a field-effect tube V1 is cut off, a coil of the relay KJ1 is powered off, a normally open contact KJ1-1 is disconnected, a power supply is disconnected, the whole starting process of the engine is completed, the LED2 is extinguished at;
if the engine is not started for many times successfully, the Vrs output by the rotating speed conditioning unit is at a low level, the diode VD1 is cut off, and the Vrs does not influence the starting of the engine; however, with the charging of the capacitor C6, the voltage on the C6 continuously increases, the voltage on the resistor R5 continuously decreases, when the potential of the 3 rd pin of the U3 is higher than the potential of the 2 nd pin, the 1 st pin outputs a high level, the diode VD3 is turned on, the voltage on the C7 is kept at a high level, the potential of the 6 th pin of the U3 is always higher than the 5 th pin, the 7 th pin outputs a low level, the field effect transistor V1 is turned off, the coil of the relay KJ1 is de-energized, the normally open contact KJ1-1 is turned off, the multiple automatic starting processes of the engine are completed, the LED2 is turned off, the engine is not started successfully, a fault is indicated, and no subsequent.
According to the starting machine power-on working time Ta and the interval time Tb of each time specified by the product technical specification, the number n of times of automatic starting is allowed, and the method for configuring the parameters of each element of the automatic starting control device of the engine is as follows:
step 1, the principle of determining the starting time control units R10-R13 is as follows: r10 > R11 > R12, preferably R10 ═ 39K, R11 ═ 20K, R12 ═ 10K, R13 ═ 20K;
step 2, calculating the change value of the non-inverting input end of U3B, namely the change value V of the potential of the 5 th pin of U35LAnd V5HAnd calculating the parameters determined in the step 1 according to the following formula:
step 3, the method for determining R8 and R9 by the starting time coordination unit is as follows: according to the required precharge value of the capacitor C7, the formula R9/(R8 + R9) -0.6 < V5LDetermining R8 and R9, and taking R8-10K and R9-3.9K;
step 4, determining C7 and R14 of a starting time control unit according to the working time Ta of the starter on power supply each time specified by the product technical specification, wherein the method comprises the following steps: from V by C75LCharging to V5HThe time constant is calculated as the time constant,
R14×C7=Ta/ Ln[(Vcc–V5L)/(Vcc–V5H)]=10/Ln[(9–2.118)/(9–6.438)]=10.12
then selecting proper values of C7 and R14 from the series of values, and taking C7 as 100 mu F and R14 as 100k omega;
step 5, determining R15 of the starting time control unit according to the interval time Tb after each starter is powered on, C7 and R14 specified by the product technical specification, wherein the method comprises the following steps: from V by C75HDischarge to V5LThe time constant is calculated as the time constant,
(R14+R15)×C7=Tb/ Ln[(0–V5H)/(0–V5L)]=30/Ln[(–6.438)/(–2.118)]=26.98
then calculating R15 and selecting an appropriate R15 value from the series of values, R15 ═ 169k Ω;
step 6, the method selected by the starting time control units R6 and R7 is as follows: r7 is more than or equal to 3 xR 6, R6 is 10k, and R7 is 39 k;
from this the voltage V at R7 is calculatedR7:
Step 7, determining R5 and C6 of the starting number control unit according to the starting number n, wherein the method comprises the following steps: c6 charging from 0 to VR7Time T of nTa + (n-1) Tb to n (Ta + Tb), taking parameter errors into consideration, takes an intermediate value: t ═ 90+ 120)/2 ═ 115, the time constant was calculated as follows, and R5, C6 were determined:
R5×C6=T/ Ln[(Vcc–0)/(Vcc–VR7)]=115/Ln[(9–0)/(9–7.163)]=72.368
from the series of values, R5 ═ 330k Ω and C6 ═ 220 μ F were selected.