Control method for preventing engine backfiring

Abstract

The application discloses a control method for preventing engine backfiring, and the control steps are as follows: stopping the action of a crank position sensor control module of an idle start-stop control unit, at this time, the crank position sensor signal stops grounding, ensuring that the ignition coil releases the ignition current after the engine completes the compression stroke, so that the electronic injection control unit cannot send the injection and ignition instructions due to the undetectable crank position sensor signal, and the ignition coil does not charge until the idle start-stop control unit detects that the starting and power generation integrated motor is positively rotating, drives the starting and power generation integrated motor to start the positive rotation, the injection nozzle starts normal injection, the ignition coil charges again and releases the ignition current based on the crank position sensor signal after the engine completes the compression stroke, until the engine starts successfully and enters the normal idle state. The application reduces the ignition in the suction stroke during the starting process of the automatic start-stop vehicle.

Description

Technical Field

[0001] This invention relates to a method for starting an engine, and more particularly to a control method for preventing engine backfire ignition. Background Technology

[0002] With the increasing number of vehicles in cities, exhaust emissions are causing more and more serious pollution to the environment. In order to reduce exhaust emissions and fuel waste caused by idling while waiting at traffic lights or in traffic jams, more and more vehicles are equipped with automatic start-stop technology. However, due to the defects in the existing automatic start-stop control method, the ignition coil may fail to release current correctly based on the crankshaft position sensor signal when it is charging. As a result, it may automatically discharge after the charging lock-up time is reached. This may result in ignition during the intake stroke, causing air filter backfire and affecting safety. Summary of the Invention

[0003] To overcome the above-mentioned defects, the present invention provides a control method for preventing engine backfire ignition, which has the advantage of reducing the occurrence of ignition during the intake stroke of the vehicle during the automatic start-stop process.

[0004] The technical solution adopted by this invention to solve its technical problem is: a control method for preventing engine backfire ignition, the control steps of which are as follows:

[0005] S1. After receiving the start signal, the idle speed start-stop control unit determines the rotation direction of the starter-generator integrated motor: if it is determined that the starter-generator integrated motor is not in reverse, proceed to step S2; if it is determined that the starter-generator integrated motor is in reverse, proceed to step S3.

[0006] S2. Perform the engine ignition procedure according to procedure A, specifically: stop the operation of the crankshaft position sensor control module of the idle start-stop control unit. At this time, the crankshaft position sensor signal stops grounding, the electronic fuel injection control unit can receive the signal from the crankshaft position sensor, drive the starter generator motor to start rotating forward, the fuel injector starts injecting fuel normally, the ignition coil is charged and releases the ignition current after the engine completes the compression stroke based on the signal from the crankshaft position sensor, until the engine starts successfully and enters the normal idle state;

[0007] S3. The electronic fuel injection control unit determines whether the ignition coil is charging: if it is determined that the ignition coil is not charging, proceed to step S4; if it is determined that the ignition coil is charging, proceed to step S5.

[0008] S4. Perform the engine ignition procedure according to procedure B, specifically: The crankshaft position sensor control module of the idle start-stop control unit starts to operate, grounding the crankshaft position sensor signal, so that the electronic fuel injection control unit does not issue fuel injection and ignition commands because it cannot detect the crankshaft position sensor signal, and the ignition coil does not charge, until the idle start-stop control unit detects that the starter generator motor is rotating forward, and stops the operation of the crankshaft position sensor control module. At this time, the crankshaft position sensor signal is no longer grounded, the electronic fuel injection control unit can receive the crankshaft position sensor signal, drive the starter generator motor to start rotating forward, the fuel injector starts to inject fuel normally, the ignition coil is charged and releases the ignition current after the engine completes the compression stroke based on the crankshaft position sensor signal, until the engine starts successfully and enters the normal idle state;

[0009] S5. Follow procedure C to perform the engine ignition procedure, specifically: stop the operation of the crankshaft position sensor control module of the idle start-stop control unit. At this time, the crankshaft position sensor signal is no longer grounded, and the electronic fuel injection control unit can receive the signal from the crankshaft position sensor, ensuring that the ignition coil releases the ignition current only after the engine completes the compression stroke. After the ignition coil discharges, the crankshaft position sensor control module starts to operate, grounding the crankshaft position sensor signal. This causes the electronic fuel injection control unit to not issue fuel injection and ignition commands because it cannot detect the crankshaft position sensor signal, and the ignition coil does not charge until the idle start-stop control unit detects that the starter-generator motor is rotating forward. Then, it drives the starter-generator motor to start rotating forward, and the fuel injectors start injecting fuel normally. The ignition coil is charged again and releases the ignition current based on the crankshaft position sensor signal after the engine completes the compression stroke, until the engine starts successfully and enters the normal idle state.

[0010] Optionally, the crankshaft position sensor is a first Hall sensor.

[0011] Optionally, the sensor used to detect the rotation direction of the integrated start-up and power generation motor is a second Hall sensor.

[0012] Optionally, the first Hall sensor is electrically connected to the electronic fuel injection control unit and the idle start-stop control unit.

[0013] Optionally, the second Hall sensor is electrically connected to the idle start-stop control unit.

[0014] The beneficial technical effects of this invention are as follows: During startup, if the integrated starter-generator motor reverses due to pre-reverse rotation after shutdown, or if it rebounds and reverses due to mechanical resistance during the compression stroke while the ignition coil is charging, the idle start-stop control unit prevents the crankshaft position sensor control module from operating. The electronic fuel injection control unit can normally receive the signal from the crankshaft position sensor and control the ignition coil to release the ignition current after the engine completes the compression stroke. After the ignition coil has released the ignition current, the crankshaft position sensor control module is activated, and the crankshaft position sensor signal is grounded until the integrated starter-generator motor resumes forward rotation. If the above operation is not performed, the integrated starter-generator motor will not receive the crankshaft position sensor signal during reverse rotation because the crankshaft position sensor signal is always grounded. The ignition coil will continue to charge and eventually automatically discharge after reaching the charging lock-up time. Since the ignition coil automatically discharges after reaching the charging lock-up time, there is a probability that it will discharge and ignite during the engine intake stroke, which may cause backfire in the air filter. The method of this application can effectively avoid the phenomenon of backfire in the air filter. It has the advantage of reducing the occurrence of ignition during the intake stroke when the vehicle starts automatically. Attached Figure Description

[0015] Figure 1 This is a flowchart of the control method for preventing engine backfire ignition according to the present invention;

[0016] Figure 2 This is a schematic diagram of crankshaft position sensor signal control in the prior art and the present invention; Detailed Implementation

[0017] In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0018] This specific embodiment details the control method for preventing engine backfire ignition as described in this application, such as... Figure 1 and Figure 2 As shown, the control steps of this method for preventing engine backfire ignition are as follows:

[0019] S1. After receiving the start signal, the idle speed start-stop control unit determines the rotation direction of the starter-generator integrated motor: if it is determined that the starter-generator integrated motor is not in reverse, proceed to step S2; if it is determined that the starter-generator integrated motor is in reverse, proceed to step S3.

[0020] S2. Perform the engine ignition procedure according to procedure A, specifically: stop the operation of the crankshaft position sensor control module of the idle start-stop control unit. At this time, the crankshaft position sensor signal stops grounding, the electronic fuel injection control unit can receive the signal from the crankshaft position sensor, drive the starter generator motor to start rotating forward, the fuel injector starts injecting fuel normally, the ignition coil is charged and releases the ignition current after the engine completes the compression stroke based on the signal from the crankshaft position sensor, until the engine starts successfully and enters the normal idle state;

[0021] S3. The electronic fuel injection control unit determines whether the ignition coil is charging: if it is determined that the ignition coil is not charging, proceed to step S4; if it is determined that the ignition coil is charging, proceed to step S5.

[0022] S4. Perform the engine ignition procedure according to procedure B, specifically: The crankshaft position sensor control module of the idle start-stop control unit starts to operate, grounding the crankshaft position sensor signal, so that the electronic fuel injection control unit does not issue fuel injection and ignition commands because it cannot detect the crankshaft position sensor signal, and the ignition coil does not charge, until the idle start-stop control unit detects that the starter generator motor is rotating forward, and stops the operation of the crankshaft position sensor control module. At this time, the crankshaft position sensor signal is no longer grounded, the electronic fuel injection control unit can receive the crankshaft position sensor signal, drive the starter generator motor to start rotating forward, the fuel injector starts to inject fuel normally, the ignition coil is charged and releases the ignition current after the engine completes the compression stroke based on the crankshaft position sensor signal, until the engine starts successfully and enters the normal idle state;

[0023] S5. Follow procedure C to perform the engine ignition procedure, specifically: stop the operation of the crankshaft position sensor control module of the idle start-stop control unit. At this time, the crankshaft position sensor signal is no longer grounded, and the electronic fuel injection control unit can receive the signal from the crankshaft position sensor, ensuring that the ignition coil releases the ignition current only after the engine completes the compression stroke. After the ignition coil discharges, the crankshaft position sensor control module starts to operate, grounding the crankshaft position sensor signal. This causes the electronic fuel injection control unit to not issue fuel injection and ignition commands because it cannot detect the crankshaft position sensor signal, and the ignition coil does not charge until the idle start-stop control unit detects that the starter-generator motor is rotating forward. Then, it drives the starter-generator motor to start rotating forward, and the fuel injectors start injecting fuel normally. The ignition coil is charged again and releases the ignition current based on the crankshaft position sensor signal after the engine completes the compression stroke, until the engine starts successfully and enters the normal idle state.

[0024] This embodiment divides engine start-up into the following three cases:

[0025] A. During startup, the starter generator does not reverse and enters the normal startup mode. The crankshaft position sensor signal stops grounding, and the electronic fuel injection control unit can receive the signal from the crankshaft position sensor, driving the starter generator to start rotating forward. The fuel injectors start injecting fuel normally, the ignition coil is charged, and based on the signal from the crankshaft position sensor, the ignition current is released after the engine completes the compression stroke until the engine starts successfully and enters the normal idling state.

[0026] B. During startup, if the starter generator reverses due to pre-reverse rotation after shutdown, or if it rebounds and reverses due to mechanical resistance during the compression stroke but the ignition coil is not charging, the crankshaft position sensor control module of the idle start-stop control unit will activate. It will ground the crankshaft position sensor signal, preventing the electronic fuel injection control unit from issuing injection and ignition commands because it cannot detect the signal. The ignition coil will also not charge, preventing ignition when the starter generator reverses, which could damage the starter generator or affect engine performance on subsequent starts. This continues until the idle start-stop control unit detects the starter generator rotating forward, at which point the crankshaft position sensor control module stops operating. The crankshaft position sensor signal is no longer grounded, and the electronic fuel injection control unit can receive the signal, driving the starter generator to rotate forward. The fuel injectors begin normal fuel injection, the ignition coil charges, and based on the crankshaft position sensor signal, releases ignition current after the engine completes its compression stroke, until the engine starts successfully and enters normal idling.

[0027] C. During startup, if the starter generator reverses due to pre-reverse rotation after shutdown, or if it rebounds and reverses due to mechanical resistance during the compression stroke while the ignition coil is charging, the idle start-stop control unit prevents the crankshaft position sensor control module from operating. The electronic fuel injection control unit can normally receive the signal from the crankshaft position sensor and control the ignition coil to release the ignition current after the engine completes the compression stroke. After the ignition coil has released the ignition current, the crankshaft position sensor control module is activated, and the crankshaft position sensor signal is grounded until the starter generator resumes forward rotation. If the above operation is not performed, the starter generator will not receive the crankshaft position sensor signal during reverse rotation because the crankshaft position sensor signal is always grounded. The ignition coil will continue to charge and eventually automatically discharge after reaching the charging lock-up time. Since the ignition coil automatically discharges after reaching the charging lock-up time, there is a probability that it will discharge and ignite during the engine intake stroke, which may cause air filter backfire. The method of this application can effectively avoid air filter backfire. This method has the advantage of reducing the occurrence of ignition during the intake stroke in the vehicle's automatic start-stop system. It should be noted that the control method for preventing engine backfire ignition in this embodiment is only applicable to four-stroke electronic fuel injection engines.

[0028] In this embodiment, the electronic fuel injection control unit is electrically connected to the fuel injector, ignition coil, idle start-stop control unit, and crankshaft position sensor. The electronic fuel injection control unit can detect the level of the ignition coil and transmit the level signal of the ignition coil to the idle start-stop control unit. The electronic fuel injection control unit can control the working timing of the fuel injector and ignition coil according to the position of the engine crankshaft.

[0029] The idle start-stop control unit in this embodiment includes a crankshaft position sensor control module. The idle start-stop control unit is electrically connected to the starter-generator integrated motor, the crankshaft position sensor, and the electronic fuel injection control unit. The idle start-stop control unit can detect the rotation direction of the starter-generator integrated motor and determine whether the crankshaft position sensor control module should operate based on the rotation direction of the starter-generator integrated motor and the level of the fuel injector coil.

[0030] The integrated starter-generator motor in this embodiment can function as both an engine starter motor and a generator.

[0031] In this embodiment, the crankshaft position sensor can sense the position of the engine crankshaft and thus determine the current stroke of the engine. The crankshaft position sensor can transmit the crankshaft position signal to the electronic fuel injection control unit.

[0032] The generator-integrated motor in this embodiment includes a sensor capable of detecting the rotation direction of the generator-integrated motor, and the sensor is electrically connected to the idle start-stop control unit.

[0033] In this embodiment, the crankshaft position sensor control module is a pure circuit structure. In some optional embodiments, the crankshaft position sensor control module controls the signal of the crankshaft position sensor to be grounded or not grounded through a transistor or a switching transistor. The crankshaft position sensor control module is electrically connected to the generator-generator integrated motor and the electronic fuel injection control unit. The crankshaft position sensor control module can select to ground or not ground the signal of the crankshaft position sensor based on external information, including the rotation direction of the generator-generator integrated motor and the level of the ignition coil. In this embodiment, a low level ignition coil indicates charging, and a high level ignition coil indicates not charging. In this embodiment, the crankshaft position sensor control module is activated when the signal of the crankshaft position sensor is grounded, and the crankshaft position sensor control module is not activated when the signal of the crankshaft position sensor is not grounded.

[0034] Optionally in this embodiment, the crankshaft position sensor is a first Hall sensor. Setting the crankshaft position sensor as a first Hall sensor can reduce costs and improve detection accuracy.

[0035] Optionally in this embodiment, the sensor used to detect the rotation direction of the integrated generator-start motor is a second Hall sensor. Using a second Hall sensor to detect the rotation direction of the integrated generator-start motor reduces costs and increases detection accuracy.

[0036] Optionally in this embodiment, the first Hall sensor is electrically connected to the electronic fuel injection control unit and the idle start-stop control unit.

[0037] Optionally in this embodiment, the second Hall sensor is electrically connected to the idle start-stop control unit.

[0038] Using the control method for preventing engine backfire ignition in this embodiment has the advantage of reducing the occurrence of ignition during the intake stroke in the vehicle's automatic start-stop process.

Claims

1. A control method for preventing engine backfire ignition, characterized in that, The control steps are as follows: S1. After receiving the start signal, the idle speed start-stop control unit determines the rotation direction of the starter-generator integrated motor: if it is determined that the starter-generator integrated motor is not in reverse, proceed to step S2; if it is determined that the starter-generator integrated motor is in reverse, proceed to step S3. S2. Perform the engine ignition procedure according to procedure A, specifically: stop the operation of the crankshaft position sensor control module of the idle start-stop control unit. At this time, the crankshaft position sensor signal stops grounding, the electronic fuel injection control unit can receive the signal from the crankshaft position sensor, drive the starter generator motor to start rotating forward, the fuel injector starts injecting fuel normally, the ignition coil is charged and releases the ignition current after the engine completes the compression stroke based on the signal from the crankshaft position sensor, until the engine starts successfully and enters the normal idle state; S3. The electronic fuel injection control unit determines whether the ignition coil is charging: the ignition coil is charging when it is at a low level, and it is not charging when it is at a high level. If it is determined that the ignition coil is not charging, proceed to step S4 below; if it is determined that the ignition coil is charging, proceed to step S5 below. S4. Perform the engine ignition procedure according to procedure B, specifically: The crankshaft position sensor control module of the idle start-stop control unit starts to operate, grounding the crankshaft position sensor signal, so that the electronic fuel injection control unit does not issue fuel injection and ignition commands because it cannot detect the crankshaft position sensor signal, and the ignition coil does not charge, until the idle start-stop control unit detects that the starter generator motor is rotating forward, and stops the operation of the crankshaft position sensor control module. At this time, the crankshaft position sensor signal is no longer grounded, the electronic fuel injection control unit can receive the crankshaft position sensor signal, drive the starter generator motor to start rotating forward, the fuel injector starts to inject fuel normally, the ignition coil is charged and releases the ignition current after the engine completes the compression stroke based on the crankshaft position sensor signal, until the engine starts successfully and enters the normal idle state; S5. Follow procedure C to perform the engine ignition procedure, specifically: stop the operation of the crankshaft position sensor control module of the idle start-stop control unit. At this time, the crankshaft position sensor signal is no longer grounded, and the electronic fuel injection control unit can receive the signal from the crankshaft position sensor, ensuring that the ignition coil releases the ignition current only after the engine completes the compression stroke. After the ignition coil discharges, the crankshaft position sensor control module starts to operate, grounding the crankshaft position sensor signal. This causes the electronic fuel injection control unit to not issue fuel injection and ignition commands because it cannot detect the crankshaft position sensor signal, and the ignition coil does not charge until the idle start-stop control unit detects that the starter-generator motor is rotating forward. Then, it drives the starter-generator motor to start rotating forward, and the fuel injectors start injecting fuel normally. The ignition coil is charged again and releases the ignition current based on the crankshaft position sensor signal after the engine completes the compression stroke, until the engine starts successfully and enters the normal idle state.

2. The control method for preventing engine backfire ignition according to claim 1, characterized in that: The crankshaft position sensor is a first Hall sensor.

3. The control method for preventing engine backfire ignition according to claim 1, characterized in that: The sensor used to detect the rotation direction of the integrated start-up and power generation motor is a second Hall sensor.

4. The control method for preventing engine backfire ignition according to claim 2, characterized in that: The first Hall sensor is electrically connected to the electronic fuel injection control unit and the idle start-stop control unit.

5. The control method for preventing engine backfire ignition according to claim 3, characterized in that: The second Hall sensor is electrically connected to the idle start-stop control unit.

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