JP5759338B2 - Engine reverse rotation detection method and engine drive control device - Google Patents

Description

  The present invention relates to a method for detecting reverse rotation of an engine, and more particularly to a method for improving stability and reliability in detecting reverse rotation of an engine.

  As this type of conventional device, for example, with respect to a crank pulse obtained by a crank angle sensor, the reverse rotation of the engine is detected by determining whether or not the time interval between adjacent pulses is a normal value. At the time of detection, various proposals have been made and put into practical use in which the driving of the engine is stopped (see, for example, Patent Document 1).

JP 2005-127299 A (page 5-11, FIGS. 1 to 8)

  However, some types of crank angle sensors have directivity, and detection accuracy decreases during reverse rotation, making it difficult to obtain normal crank pulses. The detection method may not be applicable, and is not necessarily a versatile method, and there is a problem that sufficient reliability cannot be guaranteed.

  The present invention has been made in view of the above circumstances, and provides an engine reverse rotation detection method and an engine drive control device capable of reliably detecting reverse rotation of an engine with a versatile and simple configuration.

In order to achieve the above object of the present invention, an engine reverse rotation detection method according to the present invention comprises:
When it is detected that a voltage drop of a predetermined value or a voltage drop in a predetermined voltage range has occurred in the voltage of the vehicle battery at the time of starting the engine, it is configured to determine that the reverse rotation of the engine has occurred It is.
In order to achieve the above object of the present invention, an engine drive control device according to the present invention includes:
An engine drive control device that enables drive control of the engine by performing energization control of an injector and a spark plug by an electronic control unit,
The electronic control unit is
When starting the engine, it is determined whether a voltage drop of a predetermined value or a voltage drop in a predetermined voltage range has occurred in the voltage of the vehicle battery. If it is determined that the voltage drop has occurred, the reverse of the engine It is configured to determine that rotation has occurred.

  According to the present invention, unlike conventional systems, it is possible to easily perform reliable reverse rotation detection of a highly reliable and reliable engine without relying on a crank angle sensor or the like having directivity in detection sensitivity. It has the effect of being able to do it.

It is a block diagram which shows the structural example of the engine drive control apparatus with which the engine reverse rotation detection method in embodiment of this invention is applied. It is a subroutine flowchart which shows the procedure of the engine reverse rotation detection process performed by the electronic control unit of the engine drive control apparatus shown by FIG. It is a characteristic diagram which shows the voltage change example of the battery for vehicles when an engine is started normally. It is a characteristic diagram which shows the example of a voltage change of the battery for vehicles when reverse rotation of an engine arises. It is a characteristic diagram which shows the voltage change example of the battery for vehicles at the time of pushing an engine.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.
The members and arrangements described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.
First, a configuration example of an engine drive control device to which an engine reverse rotation detection method according to an embodiment of the present invention is applied will be described with reference to FIG.
FIG. 1 shows a schematic configuration of an engine 1 and the vicinity of the engine 1. The engine 1 is provided with an injector 2 according to the number of cylinders, and a spark plug 3 is provided for each cylinder. It has become.
As is well known, the intake air sucked through the throttle valve 4 is introduced into the engine 1 through the intake pipe 5, while the exhaust gas after combustion is exhausted through the exhaust pipe 6. It has become so.

Further, a rotor plate 7 having a plurality of protrusions formed on the peripheral portion is attached to a crankshaft (not shown) of the engine 1, and a crank angle sensor 8 is provided in the vicinity of the peripheral portion of the rotor plate 7. The output signal is input to the electronic control unit 20 and used for calculation and calculation of the engine speed.
The electronic control unit 20 has, for example, a microcomputer (not shown) having a known and well-known configuration, a storage element (not shown) such as a RAM and a ROM, and the injector 2 is energized and driven. The drive circuit (not shown) for performing and the electricity supply circuit (not shown) for supplying electricity to the ignition plug 3 are comprised as a main component.

In addition to the output signal of the crank angle sensor 8, as described above, for example, the accelerator opening, the outside air temperature, the atmospheric pressure, and the like are detected and input to the electronic control unit 20 by various sensors (not shown). The control unit 20 is used for operation control of the engine 1, fuel injection control, and engine reverse rotation processing described later.
The electronic control unit 20 is supplied with power by the vehicle battery 10 when the ignition switch 9 is turned on.

FIG. 2 is a subroutine flowchart showing the engine reverse rotation detection process executed by the electronic control unit 20, and the contents thereof will be described below with reference to FIG.
First, as a precondition, the series of subroutine processing shown in FIG. 2 is executed on the condition that the rotation of the engine 1 is confirmed in a main routine (not shown). Normally, in the electronic control unit 20 in which engine control processing or the like is executed, the control processing of the engine 1 is performed by determining a predetermined parameter or the like, and the determination result is, for example, a flag. It has come to be remembered. Therefore, it is preferable that the processing shown in FIG. 2 is started when a predetermined value indicating engine rotation is set in the flag.

Thus, when processing is started by the electronic control unit 20, it is first determined whether or not there is an input of a crank pulse (see step S102 in FIG. 2).
That is, it is determined whether or not there is an input from the crank angle sensor 8, and when it is determined that there is an input from the crank angle sensor 8, that is, there is an input of a crank pulse (in the case of YES), the following will be described. While the process proceeds to step S104, when it is determined that no crank pulse is input (in the case of NO), it is determined that the engine 1 is not rotating (engine non-rotating) (step S114 in FIG. 2). Return to the main routine that is not performed. In the main routine, a control process for dealing with a failure is usually prepared. When the engine 1 is in a non-rotating state, a necessary process such as an alarm is executed.

In step S104, the battery voltage VB of the vehicle battery 10 is input to the electronic control unit 20, the voltage value is stored in a predetermined storage area, and the process proceeds to step S106.
In S106, it is determined whether or not the battery voltage VB input as described above is within a predetermined voltage range.
Specifically, it is determined whether VBtyp>VB> VBdwn is satisfied. Here, VBtyp is a standard voltage when the vehicle battery 10 is normal, and VBdwn is a minimum voltage value when the battery voltage decreases when the reverse rotation of the engine 1 occurs.

Here, the determination as described above is based on the result of the inventor's earnest examination and research on the correlation between the engine reverse rotation and the battery voltage.
That is, in the process of step S106 described above, as a result of the inventor's earnest examination and research, the battery voltage when the engine 1 is normally started by cranking by a starter motor (not shown) is shown in FIG. As shown in the example of the battery voltage waveform, the voltage drops to a voltage at a stretch at the start of rotation (at time t1 in FIG. 3), and then gradually rises to a voltage that is about half of the voltage drop that occurred earlier. Then, it was found that the increased voltage stagnated for a while, and then showed a change that gradually recovered to the original battery voltage with a slow change. Here, if the vehicle battery 10 has a voltage of, for example, 12V, the magnitude of the voltage drop at the time t1 is approximately 4 to 5V. In other words, at this time, the battery voltage drops to, for example, about 8 to 7V.

On the other hand, when the reverse rotation of the engine 1 occurs, as shown in the example of the battery voltage waveform in FIG. 4, the battery voltage is a relatively small voltage drop compared to the normal case (see FIG. 3). The inventors of the present application have found that as a result of diligent tests and researches, the engine 1 shows a change that is maintained at the reduced battery voltage while the engine 1 is in the reverse rotation state. In this case, the voltage drop is approximately 1V in the case of a 12V vehicle battery.
When the engine 1 is normally started, the power generation output from the alternator (not shown) is normally charged to the vehicle battery 10 via a rectifier circuit (not shown). Therefore, the reverse current generated in the alternator (not shown) during the reverse rotation of the engine is theoretically interrupted by the rectifier circuit (not shown), but actually a small reverse current flows. As a result, it is assumed that a relatively small battery voltage drop as described above occurs.

The determination in step S106 is based on the results of such tests and researches by the inventor of the present application, and in the case of a 12V vehicle battery, the previous VBdwn is preferably set to a value around 11V, for example.
The value of VBdwn is preferably set based on a test or a simulation result in consideration of the type of vehicle battery, specific specifications of the engine drive control device, and the like.
FIG. 5 shows an example of battery voltage change when the engine 1 is started by so-called pushing. In this case, it is confirmed that the battery voltage hardly changes.

  Therefore, when it is determined in step S106 that VBtyp> VB> VBdwn is satisfied (in the case of YES), that is, in other words, the battery voltage is in a voltage range where it can be determined that the engine reverse rotation has occurred. When it is determined that the engine speed has decreased, it is determined that the engine reverse rotation has occurred (see step S108 in FIG. 2), and the process once returns to the main routine (not shown). In the main routine, necessary processing preset in accordance with each device is executed based on the determination result that the engine 1 is in the reverse rotation state.

  In this example, it is determined in step S106 whether or not the voltage drop of the battery voltage is within a predetermined voltage range as represented by the above inequality (VBtyp> VB> VBdwn). However, it may be determined whether or not the battery voltage has dropped by a predetermined voltage.

  Further, from the viewpoint of keeping the reliability of the determination high, as described above with reference to FIG. 4, while the engine 1 is in the reverse rotation state, the battery voltage decreases to a substantially constant state. In consideration, when the determination in step S106 is YES, it is determined whether or not the battery voltage is in a substantially constant state for a predetermined time, and it is determined that the battery voltage is in a substantially constant state. It is also preferable to proceed to step S108.

On the other hand, if it is determined in step S106 that VBtyp>VB> VBdwn is not satisfied (in the case of NO), it is determined whether VB> VBst is satisfied (FIG. 2). (See step S110).
Here, VBst is a normal reference battery voltage that serves as a reference when determining that the engine 1 has been normally started.

Considering that when the engine 1 is normally started, as described above with reference to FIG. 3, the battery voltage once shows a change that causes a certain voltage drop and then gradually recovers. VBst is preferably set to about the maximum value of the battery voltage drop. That is, as illustrated in the description of FIG. 3 above, in the case of a 12V vehicle battery, the battery voltage drops to about 7V at the time of starting. Therefore, in this case, VBst is preferably set to a value around 7V.
The value of VBst is preferably set based on the results of tests and simulations in consideration of the type of vehicle battery, specific specifications of the engine drive control device, and the like.

Therefore, when it is determined in step S110 that VB> VBst is satisfied (in the case of YES), it is determined that the engine 1 is normally started (see step S112 in FIG. 2). The process returns to the main routine (not shown).
On the other hand, if it is determined in step S110 that VB> VBst is not satisfied (in the case of NO), it cannot be determined whether or not the engine rotation is normal, and therefore, the process once returns to the main routine (not shown). . In this case, in the main routine, in response to the fact that the rotational state of the engine 1 cannot be determined, other processing for confirming the operating state of the engine 1 is executed. The specific processing to be executed is determined by each device and need not be limited to a specific processing.

  It is suitable for an engine drive control device in which simple and reliable engine reverse rotation detection is desired.

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Injector 3 ... Spark plug 8 ... Crank angle sensor 10 ... Vehicle battery 20 ... Electronic control unit

Claims (4)

An engine reverse rotation detection method for detecting reverse rotation of an engine,
An engine characterized in that it is determined that reverse rotation of the engine has occurred when it is detected that a voltage drop of a predetermined value or a voltage drop in a predetermined voltage range has occurred in the voltage of the vehicle battery at the time of starting the engine. Reverse rotation detection method.   2. The engine reverse rotation detection method according to claim 1, wherein when the voltage after the voltage drop is determined to be substantially constant, it is determined that reverse rotation of the engine has occurred. An engine drive control device that enables drive control of the engine by performing energization control of an injector and a spark plug by an electronic control unit,
The electronic control unit is
When starting the engine, it is determined whether a voltage drop of a predetermined value or a voltage drop in a predetermined voltage range has occurred in the voltage of the vehicle battery. If it is determined that the voltage drop has occurred, the reverse of the engine An engine drive control device configured to determine that rotation has occurred. Electronic control unit
4. The engine drive control device according to claim 3, wherein the engine drive control device is configured to determine that the reverse rotation of the engine occurs when it is determined that the voltage after the voltage drop is substantially constant.

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