TWI414674B - Engine idling automatic flameout system and its control method - Google Patents

Abstract

The present invention discloses an engine idle speed automatially shut down system and method thereof which comprises: an engine control unit comprising a vehicle speed sensor, an engine revolution speed sensor, a throttle valve opening sensor, and a temperature sensor, an idle speed/shut off switch, a signal switch and an idle speed/shut off control unit. When the vehicle speed sensed by the vehicle speed sensor is less than the default speed, the engine revolution speed sensed by the engine revolution speed sensor is less than the default speed, the throttle valve opening sensed by the throttle valve opening sensor is less than the default opening, and the engine operating temperature sensed by the temperature sensor is higher than the default temperature, and the sustention time of the above conditions is longer than the default time, the idle speed/shut off control unit controls the signal switch to break the circuit between the crank positioning sensor and the engine control unit.

Description

Engine idle speed automatic flameout system and control method thereof

The invention relates to an engine idle speed automatic flameout system and a control method thereof, in particular to an idle speed automatic flameout system suitable for a locomotive engine and a control method thereof.

The exhaust gas emitted by steam locomotives is one of the main factors causing air pollution and the greenhouse effect. The concentration of exhaust gas emitted by locomotives during idle speed (such as the red light at intersections) is several times that of normal driving, so it is necessary to effectively prevent them. The best way to discharge exhaust gas from an locomotive is to turn off the engine.

In addition, due to the increasingly stringent requirements of environmental protection regulations, national environmental protection related units gradually require steam and locomotives to wait for traffic lights, traffic jams, and roadside suspensions, that is, when idle speed exceeds a certain period of time (such as 5 minutes), it must be mandatory. The engine is off. Therefore, how to control the engine to automatically extinguish the flame at idle speed, suppress the gas emissions of steam and locomotives, and reduce the consumption of gasoline fuel is an urgent problem for vehicle manufacturers.

Generally, the locomotive start and stop modes mostly use the key to turn the locomotive lock. Please refer to Figure 1 for a schematic diagram of the circuit of the engine start and stop system. Generally speaking, when starting the engine 70, the rider needs to turn the locomotive with the right hand key. The lock head, that is, the power switch 74 is first activated to connect the battery 73, and then the brake switch 75 is activated by the left hand. At this time, the brake light 76 will be bright, that is, the brake circuit must be turned on before the engine 70 can be started to avoid the explosion, and then the right hand The start switch 77 is pressed, the start control motor 79 is turned on, the starter motor 78 is turned on, and the engine 70 is started via the power control switch 71 and the igniter 72. The related information of the engine 70 operation is displayed on the meter indicator light 80. In addition, when the engine 70 is to be turned off during idle speed, the rider needs to reverse the key to cut off the power. Therefore, for the locomotive rider, during the engine stall and start-up process, both hands must move back and forth between the handlebar and the lock of the locomotive, which is very cumbersome and inconvenient to operate, which is not very ideal.

Some locomotives that have been on the market in recent years have used the engine control unit (ECU) of the jet engine to detect whether the handle of the locomotive is not being held, etc. based on the engine speed, speed and grip sensor. To determine if the engine should be turned off. Referring to FIG. 2 , another system architecture diagram of an engine idle stop is shown. The system architecture mainly includes a grip sensor 91 , a vehicle speed sensor 92 , a timer 93 and a control unit 94 . The grip sensor 91 is used to detect whether the handle of the locomotive is gripped, the speed sensor 92 is used to measure the speed of the locomotive, and the timer 93 is used to measure the duration that the handle is not held, the control unit 94 is electrically connected to the gripper sensor 91, the vehicle speed sensor 92, and the timer 93.

When the engine 95 of the locomotive is in the starting state, the gripper sensor 91 detects that the handle is not gripped, the timer 93 measures that the duration of the handle is not held reaches a predetermined value, and the vehicle speed sensor 92 measures the locomotive. When the vehicle speed is zero, that is, the locomotive system is in idle speed, the control unit 94 outputs a signal to control the engine 95 of the locomotive to be turned off.

This method can judge and help the rider to complete the automatic flameout action. However, most of the operation methods are to directly stop the oil supply to the engine to achieve the idling stop, but the circuit circuit for directly cutting the injector has its shortcomings, because the signal voltage of the injector is 12 volts (V). The main actuator of the injector is an electromagnetic coil. After the conduction, the electromagnetic coil magnetically lifts the ejector pin in the flow channel, so that the inductance phenomenon generated when the gasoline is ejected but the circuit loop is disconnected must be specially made a protection circuit, which is not ideal. There is still room for improvement.

Because of this, in the spirit of active invention, the engine idle speed automatic flameout system and its control method can solve the above problems, and the research and experiment are finally completed to complete the present invention.

The main object of the present invention is to provide an engine idle speed automatic flameout system, which can directly cause the engine control unit to independently output the fuel injection signal according to the signals of the respective sensors, and achieve the purpose of idling and extinguishing. The flameout principle of the present invention is to cut off the circuit circuit of the crank position sensor and the engine control unit. The signal detected by the crank position sensor can provide the engine control unit for determining the crankshaft speed and the crankshaft position of the engine when the crankshaft position is cut off. When the circuit between the sensor and the engine control unit is turned on, even if the engine is still rotating, the signal of the crank position sensor received by the engine control unit is the same as the flameout (the crankshaft does not rotate), so the engine is not rotated, and the required fuel injection amount is required. Zero, immediately stop sending the fuel injection signal, not to make the engine enter the fault mode and stop outputting the signal. In addition, the signal voltage of the crank position sensor is lower than 1 volt (V), so the circuit design can ignore the inductance problem when the crank position sensor and the engine control unit are cut off.

In order to achieve the above object, the engine idle speed automatic flameout system of the present invention is assembled on a locomotive having an engine, and the idle automatic flameout system comprises: an engine control unit, an idle stop switch, a signal switch and an idle stop control unit. The engine control unit includes a vehicle speed sensor for measuring the locomotive, an engine speed sensor for measuring the engine, a throttle opening sensor for measuring the throttle opening, and a temperature for measuring the operating temperature of the engine. sensor. In addition, the idle stop switch is used to select and control the operation mode of the locomotive to be idle or automatic, and the signal switch is electrically connected and assembled between the crank position sensor of the measuring engine crankshaft and the engine control unit. The idle stop control unit is electrically connected to the engine control unit, the signal switch and the idle stop switch, and the idle stop control unit has a timer.

When the engine is in the starting state and the idle stop switch is in the idle automatic extinguishing operation mode, the vehicle speed measured by the vehicle speed sensor is less than a predetermined vehicle speed, the engine speed measured by the engine speed sensor is less than a predetermined speed, and the throttle valve is opened. When the throttle valve measured by the degree sensor is less than a predetermined opening degree and the engine operating temperature measured by the temperature sensor is greater than a predetermined temperature, the timer starts counting, and when the above condition is established, the duration exceeds a predetermined time. At the time, the idle stop control unit determines that the locomotive is at idle speed, and controls the signal switch to open the circuit of the crank position sensor and the engine control unit, thereby causing the engine to stall.

The above signal switch can be a normally closed relay or other equivalent component.

In addition, when the engine is in the starting state and the idle stop switch is in the operation mode of the automatic idle stop, the idle stop control unit controls the signal switch without disconnecting the circuit of the crank position sensor and the engine control unit, that is, at this time, the locomotive The rider sets the locomotive's operation mode to automatic ignition without idling, and the automatic measurement is not idling, regardless of whether the data measured by the above various sensors meets the above conditions.

The operation mode of the above-mentioned idle stop switch can be displayed on the instrument of the locomotive or other types of indicator lights, that is, the operation mode of the locomotive is the idle automatic stop or the automatic idle stop state, which can be displayed on the indicator light. Let the locomotive rider see it.

The above-mentioned idle stop switch can be a push switch or other equivalent component, so that the locomotive rider can control the operation mode of the locomotive to be idling automatic flameout or automatic igniting without idling. That is, the locomotive rider is free to choose whether or not to automatically turn off the idling, and only need to press the switch to control the change.

The predetermined speed measured by the above vehicle speed sensor can be set to 3 km / h, 2 km / h or other speed, and the predetermined speed measured by the engine speed sensor can be set to 1800 rpm, 1700 rpm / Minutes or other revolutions. The predetermined opening degree measured by the throttle opening sensor can be set to 1% or other opening degree, and the predetermined temperature measured by the temperature sensor can be set to 100 degrees Celsius or other temperature. The values set by the above various qualification conditions may be set according to the performance of the engine, and the qualification conditions may be stored in a memory or other equivalent storage medium in the idle reduction control unit.

The predetermined time set by the above timer can be set to 2 seconds, 1 minute or other time, and can be set according to local environmental protection regulations, and the predetermined time can be stored in the memory or other equivalent storage medium in the idle reduction control unit.

The engine control unit may further include a voltage sensor for measuring the battery of the locomotive. When the voltage measured by the voltage sensor is lower than a predetermined voltage, the timer is not timed. That is, when the voltage of the battery is in a low voltage state, in order to avoid insufficient power to restart the engine, the idle stop control unit does not control the signal switch to be turned off, and the circuit of the crank position sensor and the engine control unit is still closed, that is, when the battery is in In the low voltage state, regardless of whether the data measured by the above various sensors meets the above conditions, the automatic flameout is not performed at an idle speed.

The predetermined voltage set by the above voltage sensor can be set to 70%, 80% or other voltage value of the normal operating voltage. The performance of the battery is set and the predetermined voltage can be stored in a memory or other equivalent storage medium in the engine control unit.

The invention further provides an engine idle speed automatic flameout control method for controlling an engine, an engine control unit, an idle reduction control unit having a timer, a signal switch, a crank position sensor and an idle stop switch One of the locomotive's idle speed is automatically turned off. The idle stop control unit is electrically connected to the engine control unit, the signal switch and the idle stop switch, and the engine control unit comprises a vehicle speed sensor of the measuring machine, an engine speed sensor of a measuring engine, and a measuring throttle valve. The opening degree throttle opening sensor and the temperature sensing device for measuring the working temperature of the engine, the control method comprises the following steps:

(A) determining whether the idle stop switch is in the idle automatic stop mode, and if so, performing the next step;

(B) determining whether the vehicle speed measured by the vehicle speed sensor is less than a predetermined vehicle speed, whether the engine speed measured by the engine speed sensor is less than a predetermined speed, and the throttle opening measured by the throttle opening sensor Whether it is less than a predetermined opening degree and whether the engine operating temperature measured by the temperature sensor is greater than a predetermined temperature, and if all is performed, the next step is performed;

(C) determining whether the timer measures the duration of the step (B) to exceed a predetermined time, and if so, performing the next step;

(D) Control the signal switch to open the circuit of the crank position sensor and the engine control unit.

In the above step (A), if the idle stop switch is not in the idle automatic stop mode, step (E) is performed: the signal switch is controlled, the circuit of the crank position sensor and the engine control unit is not disconnected, that is, the crank position sensing is closed. Circuitry of the engine and engine control unit.

That is, if the condition of the step (C) is met, the idle stop control unit determines that the locomotive is at idle, and controls the signal switch to open the circuit of the crank position sensor and the engine control unit, thereby causing the engine to stall.

The engine control unit may further include a voltage sensor for measuring the battery of the locomotive, and step (B) may further comprise determining whether the battery voltage measured by the voltage sensor is lower than a predetermined voltage, and if not, the timer is not timed. . That is, in the step (B), when the voltage of the battery is in a low voltage state, in order to avoid insufficient power to restart the engine, the idle stop control unit does not control the signal switch to be turned off, and the circuit of the crank position sensor and the engine control unit remains Closed road. In other words, when the battery is in a low voltage state, even if the vehicle speed measured by the vehicle speed sensor is less than the predetermined vehicle speed, the engine speed measured by the engine speed sensor is less than the predetermined speed, and the throttling of the throttle opening sensor is measured. The valve opening degree is less than the predetermined opening degree and the engine operating temperature measured by the temperature sensor is greater than a predetermined temperature, and is not automatically decelerated to avoid the power is insufficient to restart the engine.

3 is a system architecture diagram of a preferred embodiment of the present invention. The engine idle speed automatic flameout system of the present embodiment is assembled on a locomotive having an engine 10, including: a crankshaft of a measuring engine 10 crankshaft The position sensor 12, a battery 18, an engine control unit 20, an idle stop switch 30, a signal switch 15 and an idle stop control unit 40.

As shown in FIG. 3, the engine control unit 20 includes a vehicle speed sensor 21 for measuring the locomotive, an engine speed sensor 22 of a measuring engine 10, a throttle opening sensor 23 of a measuring engine 10, and an amount. A temperature sensor 24 for measuring the operating temperature of the engine 10 and a voltage sensor 25 for measuring the battery 18 of the locomotive.

The idle stop switch 30 is provided for the locomotive rider to select the control locomotive operating mode to be idling auto-extinguishing or non-idling auto-extinguishing, and the idling stop switch 30 operating mode is displayed on the locomotive indicator light 31, so that The operation mode of the locomotive is the automatic igniting of the idling or the automatic igniting of the idling, which can be seen by the locomotive rider. In the embodiment, the idle stop switch 30 is a push switch, which can facilitate the locomotive rider to change the operation mode of the locomotive to idle automatic stop or automatic idle without idle.

As shown in FIG. 3, the signal switch 15 is electrically connected and assembled between the crank position sensor 12 and the engine control unit 20. The idle stop control unit 40 is electrically connected to the engine control unit 20, the signal switch 15 and the idle stop switch 30, and the idle stop control unit 40 includes a timer 41.

When the engine 10 is in the starting state and the idle stop switch 30 is in the idle automatic stop mode, the vehicle speed measured by the vehicle speed sensor 21 is less than a predetermined vehicle speed, and the engine 10 measured by the engine speed sensor 22 is less than a predetermined speed. The throttle valve opening degree of the engine 10 measured by the speed and throttle opening sensor 23 is less than a predetermined opening degree, and the operating temperature of the engine 10 measured by the temperature sensor 24 is greater than a predetermined temperature and the amount of the voltage sensor 25 When the measured voltage of the battery 18 is higher than a predetermined voltage, that is, when the above conditions are met, the timer 41 starts counting, and when the above condition meets the duration exceeding a predetermined time, the idle reduction control unit 40 determines the locomotive system at this time. While at idle, the signal switch 15 is immediately controlled to open the circuit of the crankshaft position sensor 12 and the engine control unit 20, thereby causing the engine to stall. In this embodiment, the signal switch 15 is a normally closed relay.

In other words, when the voltage of the battery 18 measured by the voltage sensor 25 is lower than a predetermined voltage, that is, when the voltage of the battery 18 is in a low voltage state, the idle stop control unit 40 does not control the signal in order to prevent the power from being insufficient to restart the engine. The switch 15 opens the circuit of the crankshaft position sensor 12 and the engine control unit 20. That is, even if the data measured by the above various sensors 21-24 meets the above conditions, the crank position sensor 12 and the engine control unit 20 are still closed, and are automatically turned off without idle.

In addition, when the engine 10 is in the starting state and the idle stop switch 30 is in the operation mode of not idling and automatic flameout, that is, at this time, the locomotive rider sets the locomotive operation mode to automatic ignition without idling, regardless of the above various sensors 21-25 Whether the measured data meets the above conditions, the idle stop control unit 40 controls the signal switch 15 without disconnecting the circuit of the crank position sensor 12 and the engine control unit 20, that is, automatically de-igniting without idle.

In the present embodiment, the predetermined vehicle speed is set to 3 km/h, the predetermined rotation speed is set to 1800 rpm, the predetermined opening degree is set to 1% of the full opening degree, and the predetermined temperature is set to 100 degrees Celsius. The predetermined voltage is set to 80% of the normal operating voltage. The operating voltage of the general locomotive battery is 12 volts (V), that is, the predetermined voltage is set to 9.6 volts (V), and the predetermined time is set to 2 seconds.

Therefore, in the idle automatic extinguishing operation mode of the embodiment, the engine control unit 20 can directly cut off the circuit of the crank position sensor 12 and the engine control unit 20 after directly calculating the data according to the sensors 21 to 25. The circuit stops the output of the fuel injection signal to achieve the purpose of automatic flameout. That is, when the circuit circuit of the crank position sensor 12 and the engine control unit 20 is cut off, even if the engine 10 is still rotating, the signal of the crank position sensor 12 received by the engine control unit 20 is the same as the flameout (the crankshaft does not rotate). Therefore, it is determined that the engine 10 does not rotate, the required injection amount is zero, and the injection of the fuel injection signal is immediately stopped, and the engine 10 is not caused to enter the failure mode and the output signal is stopped. In addition, since the signal voltage of the crank position sensor 12 is lower than 1 volt (V), the inductance problem when the crank position sensor 12 and the engine control unit 20 are cut off can be neglected in the circuit design, thereby reducing the cost.

Please refer to FIG. 4 for a control flow chart of a preferred embodiment of the present invention, and please refer to FIG. 3 together. The engine idle speed automatic flameout control method of the embodiment is for controlling an engine 10, an engine control unit 20, an idle reduction control unit 40 having a timer 41, a signal switch 15, a crank position sensor 12 and The idle speed automatic extinguishing of one of the idling switch 30 is electrically connected to the engine control unit 20, the signal switch 15 and the idle stop switch 30, and the engine control unit 20 includes a speed sensor of the measuring locomotive. 21. An engine speed sensor 22 for measuring the engine 10, a throttle opening sensor 23 for measuring the throttle opening, a temperature sensor 24 for measuring the operating temperature of the engine 10, and a measuring locomotive The voltage sensor 25 of the battery 18 includes the following steps: first, determining whether the idle stop switch 30 is in an idle automatic extinguishing operation mode (S901), and if so, performing the next step; and then, determining the vehicle speed perception Whether the vehicle speed measured by the controller 21 is less than a predetermined vehicle speed, and whether the engine 10 speed measured by the engine speed sensor 22 is less than a predetermined speed, the throttle opening degree Whether the throttle opening measured by the controller 23 is less than a predetermined opening degree, whether the operating temperature of the engine 10 measured by the temperature sensor 24 is greater than a predetermined temperature, and whether the voltage of the battery 18 measured by the voltage sensor 25 is high. At a predetermined voltage (S902), if all is, the next step is performed; then, it is determined whether the duration measured by the timer 41 conforms to the duration of each of the perceptrons 21~25 exceeds a predetermined time (S903), and if so, execution is performed. Next step; then, the signal switch 15 is controlled to open the circuit of the crank position sensor 12 and the engine control unit 20 (S904); then, it is judged whether the engine 10 speed is 0 (S905); if yes, the next step is performed; The signal switch 15 closes the circuit of the crank position sensor 12 and the engine control unit 20 (S906).

If the idle stop switch 30 is not in the idle automatic stop mode, jump directly to: the signal switch 15 closes the circuit of the crank position sensor 12 and the engine control unit 20 (S906).

As shown in FIG. 4, in the step of S902, when the voltage of the battery 18 measured by the voltage sensor 25 is lower than a predetermined voltage, that is, when the voltage of the battery 18 is in a low voltage state, in order to avoid insufficient power to restart The engine, idle stop control unit 40 does not control the circuit switch 15 to open the circuit of the crank position sensor 12 and the engine control unit 20. That is, even if the data measured by the above various sensors 21-24 meets the above conditions, the crank position sensor 12 and the engine control unit 20 are still closed, and are automatically turned off without idle.

Moreover, in the step of S903, if the condition of the step of S902 is consistent with the duration exceeding a predetermined time, the idle stop control unit 40 determines that the locomotive system is in idle speed, and then performs the step of S904, if it continues The time does not exceed the predetermined time and the step of S904 is not performed.

As shown in FIG. 4, in the step of S905, when the engine 10 speed is 0, the signal switch 15 closes the circuit of the crank position sensor 12 and the engine control unit 20. If the engine 10 speed is not 0, the signal switch 15 The circuitry of the crankshaft position sensor 12 and the engine control unit 20 is still disconnected.

In the present embodiment, the predetermined vehicle speed is set to 3 km/h, the predetermined rotation speed is set to 1800 rpm, the predetermined opening degree is set to 1% of the full opening degree, and the predetermined temperature is set to 100 degrees Celsius. The predetermined voltage is set to 80% of the normal operating voltage. The operating voltage of the general locomotive battery is 12 volts (V), that is, the predetermined voltage is set to 9.6 volts (V), and the predetermined time is set to 2 seconds, and the other signal switch is set. The 15 series is a normally closed relay.

The above-mentioned embodiments are merely examples for convenience of description, and the scope of the claims is intended to be limited to the above embodiments.

10. . . engine

12. . . Crankshaft position sensor

15. . . Signal switch

18. . . battery

20. . . Engine control unit

twenty one. . . Speed sensor

twenty two. . . Engine speed sensor

twenty three. . . Throttle opening sensor

twenty four. . . Temperature sensor

25. . . Voltage sensor

30. . . Idle speed switch

31. . . Indicator light

40. . . Idle stop control unit

41. . . Timer

70. . . engine

71. . . Power control switch

72. . . lighter

73. . . battery

74. . . switch

75. . . Brake switch

76. . . Brake lamp

77. . . Start switch

78. . . start the motor

79. . . Start control switch

80. . . Instrument indicator

91. . . Grip sensor

92. . . Speed sensor

93. . . Timer

94. . . control unit

95. . . engine

FIG. 1 is a schematic diagram of a circuit of a conventional engine starting and extinguishing system.

FIG. 2 is a system architecture diagram of another conventional engine idle stop.

3 is a system architecture diagram of a preferred embodiment of the present invention.

4 is a control flow diagram of a preferred embodiment of the present invention.

10. . . engine

12. . . Crankshaft position sensor

15. . . Signal switch

18. . . battery

20. . . Engine control unit

twenty one. . . Speed sensor

twenty two. . . Engine speed sensor

twenty three. . . Throttle opening sensor

twenty four. . . Temperature sensor

25. . . Voltage sensor

30. . . Idle speed switch

31. . . Indicator light

40. . . Idle stop control unit

41. . . Timer

Claims (9)

An engine idle speed automatic flameout system is set on a locomotive having an engine, comprising: an engine control unit, comprising a vehicle speed sensor for measuring the locomotive, an engine speed sensor for measuring the engine, and a measuring machine a throttle opening sensor of the throttle opening and a temperature sensor for measuring the working temperature of the engine; an idle stop switch for selecting and controlling the running mode of the locomotive to be idle or automatic ignition a signal switch electrically connected and disposed between a crank position sensor of the engine crankshaft and the engine control unit; and an idle stop control unit electrically connected to the engine control unit, the signal switch and the The idle stop switch includes a timer; when the engine is in a running state and the idle stop switch is in an idle automatic stop mode, the speed measured by the vehicle speed sensor is less than a predetermined speed, and the engine speed sensor is The measured engine speed is less than a predetermined speed, and the throttle opening measured by the throttle opening sensor is less than a predetermined opening degree and When the engine operating temperature measured by the temperature sensor is greater than a predetermined temperature, the timer starts counting, and when the above condition is established for a duration exceeding a predetermined time, the idle stop control unit controls the signal switch to disconnect the a circuit of the crankshaft position sensor and the engine control unit; wherein the predetermined vehicle speed is 3 km/h, and the predetermined speed is 1800 rpm, and the predetermined opening is 1%, and the predetermined temperature is Refers to 100 degrees Celsius. The engine idle speed automatic flameout system according to claim 1, wherein the signal switch is a normally closed relay. The engine idle speed automatic flame-extinguishing system according to claim 1, wherein the idle-speed flameout control unit controls the signal switch when the engine is in an active state and the idle-stop switch is in an idle-speed automatic flameout operation mode. The circuit of the crankshaft position sensor and the engine control unit is opened. The engine idle speed automatic flameout system according to claim 1, wherein the operation mode of the idle stop switch is displayed on one of the indicator lights of the locomotive. The engine idle speed automatic flameout system according to claim 1, wherein the idle speed switch is a push switch. The engine idle speed automatic flameout system according to claim 1, wherein the engine control unit further comprises a voltage sensor for measuring the battery of the locomotive, wherein the battery voltage measured by the voltage sensor is lower than a predetermined one. The timer does not count when the voltage is applied. An engine idle speed automatic flameout control method for controlling a locomotive having an engine, an engine control unit, an idle stop control unit having a timer, a signal switch, a crank position sensor and an idle stop switch The idle speed automatic extinguishing control unit is electrically connected to the engine control unit, the signal switch and the idle stop switch, the engine control unit includes a vehicle speed sensor for measuring the locomotive, and measuring the engine speed of the engine a sensor, a throttle opening sensor for measuring the opening of the throttle valve, and a temperature sensor for measuring the operating temperature of the engine, the controller The method includes the following steps: (A) determining whether the idle stop switch is in an idle automatic stop mode, and if so, performing the next step; (B) determining whether the measured speed of the vehicle speed sensor is less than a predetermined speed, Whether the engine speed measured by the engine speed sensor is less than a predetermined speed, whether the throttle opening measured by the throttle opening sensor is less than a predetermined opening degree, and the engine operation measured by the temperature sensor Whether the temperature is greater than a predetermined temperature, if all is performed, the next step is performed; (C) determining whether the timer measures the duration of the step (B) to exceed a predetermined time, and if so, performing the next step; D) controlling the signal switch to open the circuit of the crank position sensor and the engine control unit. The engine idle speed automatic flameout control method according to claim 7, wherein in the step (A), if the idle stop switch is not in the idle automatic flameout operation mode, performing step (E): controlling the The signal switch does not disconnect the circuit of the crank position sensor and the engine control unit. The engine idle speed automatic flameout control method according to claim 7, wherein the engine control unit further comprises a voltage sensor for measuring the battery of the locomotive, and the step (B) further comprises: determining the voltage sensor The measured battery voltage is below a predetermined voltage, and if so, the timer is not timed.