JP2010077822A - Control system for fuel injection engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance engine starting performance when a battery is deteriorated, in a control system for a fuel injection engine with operations of at least a fuel injection valve and a fuel pump controlled by an electronic control unit so that control processing is disabled when a voltage of the battery is equal to or lower than a predetermined reset voltage. <P>SOLUTION: In this control system, a prohibition signal output means 41 outputs a prohibition signal for prohibiting the operation of the fuel pump 34 by detecting the starting of the operation of a starter motor; a permission signal output means 42 outputs a permission signal for permitting the operation of the fuel pump 34 by determining that a pump operation permission state avoiding the voltage of the battery from reaching the predetermined reset voltage or lower even by the operation of the fuel pump 34 has reached prior to fuel injection by the fuel injection valve after the operation of the fuel pump 34 is stopped according to the starting of the operation of the starter motor; and a pump drive means 43 drives the fuel pump 34 according to the prohibition signal outputted from the prohibition signal output means 41 and the permission signal outputted from the permission signal output means 42. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a fuel injection valve that injects fuel, a fuel pump that supplies fuel to the fuel injection valve, a starter motor that can transmit starting power to the crankshaft, and a generator that is coupled to the crankshaft. A battery for supplying operating power to the fuel pump, the fuel injection valve, and the starter motor, and at least the fuel injection valve and the fuel so that the control processing is impossible when the voltage of the battery is equal to or lower than a predetermined reset voltage. The present invention relates to a control device for a fuel injection engine including an electronic control unit that controls the operation of a pump.

Japanese Patent Application Laid-Open No. 2004-133867 discloses an engine control device that enables a fuel pump to operate even when the battery voltage is low when starting an engine that is cranking with a starter motor.
JP 07-317620 A

  By the way, an electronic control unit that controls the operation of a fuel pump or the like is generally incapable of performing control processing in a state where the voltage of the battery is equal to or lower than a predetermined reset voltage. When the engine is started, the fuel pump can be operated even when the battery voltage is low. When the battery is deteriorated due to its long-term use, the electronic control unit performs control processing even if the deterioration degree is small. It becomes impossible and it becomes difficult to start the engine.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a control device for a fuel injection type engine with improved engine startability when the battery is deteriorated.

  To achieve the above object, a first aspect of the present invention is directed to a fuel injection valve that ejects fuel, a fuel pump that supplies fuel to the fuel injection valve, and a starter motor that can transmit starting power to a crankshaft. A generator connected to the crankshaft, a battery for supplying operating power to the fuel pump, the fuel injection valve and the starter motor, and control processing being impossible when the voltage of the battery is below a predetermined reset voltage In the control apparatus for a fuel injection type engine comprising at least an electronic control unit for controlling the operation of the fuel injection valve and the fuel pump, the electronic control unit detects the start of operation of the starter motor, and Prohibition signal output means for outputting a prohibition signal for prohibiting the operation of the fuel pump, and start of operation of the starter motor Accordingly, the pump operation permission state in which it is possible to avoid that the voltage of the battery becomes equal to or lower than the predetermined reset voltage even by the operation of the fuel pump before the fuel injection by the fuel injection valve after the operation of the fuel pump is stopped. A permission signal output means for outputting a permission signal for permitting the operation of the fuel pump by determining that the fuel pump has been operated, and stopping the operation of the fuel pump in response to a prohibition signal output from the prohibition signal means, And pump driving means for driving the fuel pump so as to start the operation of the fuel pump in response to the permission signal output from the permission signal output means after being output.

  Further, the invention according to claim 2 includes a starter switch for controlling the operation of the starter motor in addition to the configuration of the invention according to claim 1, and the prohibition signal output means is based on a change in the switching mode of the starter switch. The start of operation of the starter motor is detected.

  According to a third aspect of the present invention, in addition to the configuration of the first aspect of the present invention, it further includes a voltage detection means for detecting the voltage of the battery, and the battery voltage detected by the voltage detection means is below a predetermined prohibition threshold. The inhibition signal output means determines that the operation of the starter motor is started in response to the decrease.

  A fourth aspect of the invention includes a crank sensor that outputs a crank pulse corresponding to the rotation of the crankshaft, in addition to the configuration of the first aspect of the invention. The pump operation permission state is determined when the crank angle of the crankshaft reaches a predetermined value based on the crank pulse.

  The invention according to claim 5 includes, in addition to the configuration of the invention according to any one of claims 1 to 3, voltage detection means for detecting the voltage of the battery, wherein the permission signal output means is the voltage detection means. It is determined that the pump operation permission state has been reached in response to the battery voltage detected in step (b) exceeding a predetermined permission threshold.

  Furthermore, in the invention described in claim 6, in addition to the configuration of the invention described in any one of claims 1 to 3, the permission signal output means has passed a predetermined time from the prohibition signal output from the prohibition signal output means. In response to this, it is determined that the pump operation permission state has been reached.

  According to the first aspect of the present invention, at the start of the starter motor operation, it is avoided that the battery voltage becomes lower than the reset voltage by the fuel pump operation before the fuel injection after the fuel pump operation is temporarily stopped. The permission signal output means determines whether or not the pump operation permission state has been reached, and the start of the fuel pump is started when the permission signal output means determines that the state has been reached. Even when the battery is deteriorated at the time of starting the engine, the electronic control unit can be prevented from being disabled by the operation of the fuel pump, thereby improving the startability.

  According to the second aspect of the invention, since the start of the starter motor is detected based on the change of the switching mode of the starter switch, the start of the starter motor can be reliably detected.

  According to the third aspect of the present invention, since it is determined that the starter motor operation has started in response to the battery voltage dropping below a predetermined prohibition threshold, the starter motor operation is controlled by the electronic control unit. Even those not controlled can be easily applied.

  According to the fourth aspect of the present invention, it is determined that the pump operation is permitted when the crank angle of the crankshaft reaches a predetermined value based on the crank pulse, and the crank angle is cranked by the starter motor. Based on the fact that the ignition and fuel injection timing is determined by the above, it is possible to reliably determine the pump operation permission state before fuel injection and start the operation of the fuel pump.

  According to the fifth aspect of the present invention, since it is determined that the pump operation permission state has been reached in response to the battery voltage exceeding the predetermined permission threshold, the battery voltage is also reset by the operation of the fuel pump. It is possible to reliably determine the pump operation permission state that can avoid the following.

  According to the sixth aspect of the present invention, it is determined that the pump operation permission state has been reached when a predetermined time elapses after the operation of the fuel pump is prohibited by the prohibition signal output from the prohibition signal output means. Therefore, simple control that is not related to the crank angle or the battery voltage is possible, and can be easily applied to a conventional engine.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 4 show a first embodiment of the present invention. FIG. 1 is a diagram showing a configuration of a control system of a fuel injection type engine. FIG. 2 is a fuel at the time of engine start in an electronic control unit. FIG. 3 is a flowchart showing a fuel pump control procedure at the time of starting the engine, FIG. 4 is a time-dependent change in starter motor, battery voltage, fuel pump and engine speed at the time of starting the engine. It is a timing chart which shows.

  First, in FIG. 1, a crankshaft 15 is rotatably supported on a crankcase 12 of an engine body 11 in a fuel injection type engine, and is slidably fitted to a cylinder block 13 coupled to the crankcase 12. A piston 16 is connected to the crankshaft 15 via a connecting rod 17. In addition, a starter motor 18 for transmitting starting power to the crankshaft 15 at the time of starting is connected to the crankshaft 15 via a speed reduction mechanism 19, and a generator 20 that generates electric power according to the rotation of the crankshaft 15. Are connected coaxially.

  A cylinder head 14 constituting a part of the engine body 11 is coupled to the cylinder block 13 so as to form a combustion chamber 21 facing the top of the piston 15 with the cylinder block 13. The cylinder head 14 is provided with an intake port 22 and an exhaust port 23 that can communicate with the combustion chamber 21, and an intake valve 24 that switches between connection and disconnection of the intake port 22 to the combustion chamber 21, and an exhaust port 23. An exhaust valve 25 that switches between communication and shut-off to the combustion chamber 21 is disposed in the cylinder head 14 so as to be able to open and close, and an ignition plug 26 is attached to the cylinder head 14 so that the tip of the combustion chamber 21 faces. The ignition coil 27 is connected to the spark plug 26.

  The intake device 28 connected to the intake port 22 includes a throttle body 30 having an intake passage 29 connected to the intake port 22. A throttle valve 31 that opens and closes the intake passage 29 is provided in the throttle body 30. Is disposed so as to be capable of opening and closing, and a fuel injection valve 32 for injecting fuel is attached. Thus, the fuel in the fuel tank 33 is supplied to the fuel injection valve 32 from a fuel pump 34 disposed at the bottom of the fuel tank 33.

  The fuel pump 34, the fuel injection valve 32, and the starter motor 18 are supplied with operating power from a battery 35, and at least the operation of the fuel injection valve 32 and the fuel pump 34, in this embodiment, The operation of the fuel injection valve 32, the fuel pump 34 and the starter motor 18 and the ignition timing of the ignition plug 26 by the ignition coil 27 are controlled by an electronic control unit 36. A crank pulse from a crank sensor 38 fixedly arranged opposite to the outer periphery of the pulsar 37 fixed to the crankshaft 15, a signal from a starter switch 39 for determining the start timing of the starter motor 18, and a battery 35 The battery voltage is input from the voltage detecting means 40 for detecting the voltage.

  A portion of the electronic control unit 36 related to the control of the fuel pump 34 at the start of the engine is a prohibition signal for detecting the start of the starter motor 18 and prohibiting the operation of the fuel pump 34 as shown in FIG. The voltage of the battery 35 is also caused by the operation of the fuel pump 34 before the fuel injection by the fuel injection valve 32 after the operation of the fuel pump 34 is stopped in response to the start of the operation of the starter motor 18. A permission signal output means 42 that outputs a permission signal for permitting the operation of the fuel pump 34 by determining that a pump operation permission state that can prevent the voltage from becoming lower than a predetermined reset voltage is obtained, and a prohibition signal from the prohibition signal means 42 In response to the output of the permission signal from the permission signal output means after the operation of the fuel pump 34 is stopped according to the output and the prohibition signal is output. So as to initiate the operation of the charge pump 34 includes a pump drive means 43 for driving the fuel pump 34.

  Thus, the prohibition signal output means 41 detects the start of operation of the starter motor 18 based on a change in the switching mode of the starter switch 39 that controls the operation of the starter motor 18, and the permission signal output means 42 When the crank angle of the crankshaft 15 reaches a predetermined value before the fuel injection from the fuel injection valve 32 is started based on the crank pulse output from the crank sensor 38 according to the rotation of the crankshaft 15, For example, when the piston 16 reaches top dead center, it is determined that the pump operation is permitted.

  Such an electronic control unit 38 performs operation control of the fuel pump 34 at the time of engine start according to the procedure shown in FIG. 3, and in step S1, the crank control is performed based on the crank pulse output from the crank sensor 38. The crank angle of the shaft 15 is calculated, and in step S2, it is determined whether or not the crank angle has reached a predetermined value. That is, step S1 and step S2 are processing steps executed by the permission signal output means 42. When it is determined that the crank angle has not reached the predetermined value, the process proceeds from step S2 to step S3.

  In step S3, it is determined whether or not the starter switch 39 is in an on state in order to start the operation of the starter motor 18, and when it is determined that the starter switch 39 is in an off state, the process proceeds to step S4. In this step S4, it is determined whether or not the battery voltage VB detected by the voltage detecting means 40 exceeds a predetermined value V1, for example, 7V. If it exceeds the predetermined value V1, the process proceeds from step S4 to step S5 to count the counter. When the value is added by “1” and it is determined that the count value is less than “20” in the next step S6, the process proceeds from step S6 to step S7 to operate the fuel pump 34, and the count value is “20”. If it exceeds, the process proceeds from step S6 to step S8, and the operation of the fuel pump 34 is stopped.

  That is, when starting the engine, the fuel pump 34 is operated as a preliminary drive before the starter motor 18 is started, and the arithmetic processing by the electronic control unit 36 is executed every 100 milliseconds, for example. 34 is preliminarily driven for a maximum of 2 seconds, for example.

  The determination process in step S3 is performed by the prohibition signal output means 41. When it is determined that the starter switch 39 for controlling the operation of the starter motor 18 is in the ON state, the process proceeds from step S3 to step S8, and the fuel pump The prohibition signal for prohibiting the operation of 34 is output.

  If it is determined in step S2 that the crank angle has reached a predetermined value, it is determined that the pump operation is permitted. In step S9, it is confirmed that no engine stall has occurred, and then the process proceeds to step S7 to output an operation permission signal. It will be.

  According to such control at the time of engine start by the electronic control unit 36, when the engine is started, the starter motor 18, the battery voltage VB, the fuel pump 34, and the engine speed NE change as shown in FIG. The starter switch 39 confirmed that the starter motor 18 was started at the time t1 after the fuel pump 34 was preliminarily driven for a time of less than 2 seconds with the battery voltage VB exceeding the predetermined value V1. Sometimes the operation of the fuel pump 34 is stopped.

  Thus, if the operation of the fuel pump 34 is continued, the battery voltage VB should decrease rapidly as shown by the broken line in response to the start of the operation of the starter motor 18, but the operation of the fuel pump 34 as described above. Is temporarily stopped, the amount of decrease in the battery voltage VB due to the start of operation of the starter motor 18 can be kept small.

  When starting power is input to the crankshaft 15 by the operation of the starter motor 18 from the time t1, the generator 20 connected to the crankshaft 15 is operated, and the battery voltage VB gradually increases due to charging by the power generation. To do. At time t2 after the operation of the fuel pump 34 stops at the time t1, it is detected that the piston 16 before reaching the top dead center has reached the crank angle before the fuel injection from the fuel injection valve 32 is started. Then, the operation of the fuel pump 34 is started.

  Next, the operation of the first embodiment will be described. When the starter motor 18 starts operating, the voltage of the battery 35 is also reset by the operation of the fuel pump 34 before the fuel injection after the operation of the fuel pump 34 is temporarily stopped. The permission signal output means 42 determines whether or not a pump operation permission state that can avoid the voltage VR (see FIG. 4) or less is reached, and the fuel pump when the permission signal output means 42 determines that the state is reached. 34 is started, the electronic control unit 36 cannot be controlled by the operation of the fuel pump 34 even when the battery 35 is deteriorated at the start of the engine in which the starter motor 18 is operated. By avoiding this, the startability can be improved.

  Further, since the start of operation of the starter motor 18 is detected based on the change in the switching mode of the starter switch 39, the start of operation of the starter motor 18 can be reliably detected.

  Further, it is determined that the pump operation is permitted when the crank angle of the crankshaft 15 reaches a predetermined value based on the crank pulse, and the ignition and fuel injection timings are determined by the crank angle during cranking by the starter motor 18. Based on the determination, the operation of the fuel pump 34 can be started by reliably determining the pump operation permission state before fuel injection.

  FIG. 5 shows a control procedure at the time of engine start according to the second embodiment of the present invention. In step S11, the battery voltage VB exceeds a predetermined prohibition threshold V2 (see FIG. 4 of the first embodiment). When it is determined that the battery voltage VB has dropped below the predetermined prohibition threshold V2, the prohibition signal output means 41 determines that the starter motor 18 has started to operate, and in step S12 the fuel is determined. A prohibition signal for prohibiting the operation of the pump 34 is output.

  When it is determined in step S11 that the battery voltage VB exceeds the predetermined prohibition threshold V2, the process proceeds from step S11 to step 13 to determine whether or not the battery voltage VB exceeds the predetermined permission threshold V3. This permission threshold value V3 is set as a value that can prevent the battery voltage VB from being equal to or lower than the reset voltage VR by the operation of the fuel pump 34 before the fuel injection by the fuel injection valve 32 after the operation of the fuel pump 34 is stopped. It is set as a value larger than the prohibition threshold V2.

  When it is determined in step S13 that the battery voltage VB is equal to or lower than the predetermined permission threshold value V3, the process proceeds to step S12. When the battery voltage VB exceeds the predetermined permission threshold value V3, it is assumed that the pump operation permission state is set. Proceed to S14.

  In step S14, it is determined whether or not engine stall has occurred. When it is determined that engine stall has not occurred, an operation permission signal is output in step S15.

  When it is determined in step S14 that an engine stall has occurred, the start count value of the start counter is incremented by "1" in step S16, and it is determined in the next step S17 that the start count value exceeds "20". Sometimes, the process proceeds to step S12. When it is determined that the start count value is "20" or less, the process proceeds to step S15.

  According to the second embodiment, it is determined that the operation of the starter motor 18 has started in response to the battery voltage VB dropping below the predetermined prohibition threshold V2, and the operation of the fuel pump 34 is stopped. Even those in which the operation of the starter motor 18 is not controlled by the electronic control unit 36 can be easily applied.

  Further, since the pump operation permission state is determined in response to the battery voltage VB exceeding the predetermined permission threshold value V3, the voltage of the battery 35 becomes equal to or lower than the reset voltage VR even by the operation of the fuel pump 34. It is possible to reliably determine the pump operation permission state that can avoid the above.

  FIG. 6 shows a control procedure at the time of starting the engine according to the third embodiment of the present invention. In step S21, it is determined whether or not the starter switch 39 is in an ON state in order to start the operation of the starter motor 18. When it is determined that the starter switch 39 is in an OFF state, it is determined whether or not an engine stall has occurred in step S22. If it is determined that the engine has not occurred, an operation permission signal is output in step S23.

  If it is determined in step S21 that the starter switch 39 is in the ON state, the stop count value of the stop counter is incremented by “1” in step S24, and then whether or not the stop count value exceeds “10” in step S25. That is, it is determined whether or not it exceeds 1 second, and when it is determined that it is 1 second or less, the process proceeds to step S26 to output a prohibition signal for prohibiting the operation of the fuel pump 34.

  If it is determined in step S25 that the stop count value is "10" or less, the process proceeds from step S25 to step S22.

  If it is determined in step S22 that an engine stall has occurred, the start count value of the start counter is incremented by "1" in step S27. If it is determined in step S28 that the start count value exceeds "20", step S26 is performed. When it is determined that the start count value is “20” or less, the process proceeds to step S23.

  According to the third embodiment, when the starter switch 39 is turned on, the pump is activated when a predetermined time, for example, 1 second elapses after the prohibition signal for prohibiting the operation of the fuel pump 34 is output. Since it is determined that the operation is permitted, simple control that is not related to the crank angle or the battery voltage VB is possible, and can be easily applied to a conventional engine.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

It is a figure which shows the structure of the control system of the fuel injection type engine of 1st Embodiment. It is a block diagram which shows the structure of the part relevant to the fuel pump control at the time of engine starting among electronic control units. It is a flowchart which shows the fuel pump control procedure at the time of engine starting. It is a timing chart which shows a time-dependent change of the starter motor at the time of engine starting, a battery voltage, a fuel pump, and an engine speed. It is a flowchart which shows the fuel pump control procedure at the time of engine starting of 2nd Embodiment. It is a flowchart which shows the fuel pump control procedure at the time of engine starting of 3rd Embodiment.

Explanation of symbols

15 ... crankshaft 18 ... starter motor 20 ... generator 32 ... fuel injection valve 34 ... fuel pump 35 ... battery 36 ... electronic control unit 38 ... crank sensor 39 ... Starter switch 40 ... Voltage detection means 41 ... Inhibition signal output means 42 ... Permit signal output means 43 ... Pump drive means

Claims (6)

  A fuel injection valve (32) for injecting fuel, a fuel pump (34) for supplying fuel to the fuel injection valve (32), and a starter motor (18) capable of transmitting starting power to the crankshaft (15) A generator (20) connected to the crankshaft (15), and a battery (35) for supplying operating power to the fuel pump (34), the fuel injection valve (32) and the starter motor (18) And an electronic control unit (36) for controlling the operation of at least the fuel injection valve (32) and the fuel pump (34) so that the control process is impossible when the voltage of the battery (35) is equal to or lower than a predetermined reset voltage. The electronic control unit (36) detects the start of operation of the starter motor (18) and detects the start of the fuel pump. 34) a prohibition signal output means (41) for outputting a prohibition signal for prohibiting the operation of the fuel, and the fuel after the operation of the fuel pump (34) is stopped in response to the start of the operation of the starter motor (18). It is determined that the operation of the fuel pump (34) before the fuel injection by the injection valve (32) is in a pump operation permission state that can prevent the voltage of the battery (35) from being equal to or lower than the predetermined reset voltage. The permission signal output means (42) for outputting a permission signal for permitting the operation of the fuel pump (34), and the operation of the fuel pump (34) according to the prohibition signal output from the prohibition signal means (41). The operation of the fuel pump (34) is started in response to the permission signal output from the permission signal output means (42) after stopping and outputting the prohibition signal. Charge pump drive means (43) for driving the pump (34) and a control system for a fuel injection engine, which comprises a.   It includes a starter switch (39) for controlling the operation of the starter motor (18), and the prohibition signal output means (41) starts the operation of the starter motor (18) based on the switching mode change of the starter switch (39). The fuel injection type engine control device according to claim 1, wherein:   Voltage detection means (40) for detecting the voltage of the battery (35), and the prohibition signal output means in response to the battery voltage detected by the voltage detection means (40) falling below a predetermined prohibition threshold 2. The control device for a fuel injection engine according to claim 1, wherein (41) determines that the operation of the starter motor (18) is started.   A crank sensor (38) for outputting a crank pulse corresponding to the rotation of the crankshaft (15), wherein the permission signal output means (42) determines the crank angle of the crankshaft (15) based on the crank pulse; The control apparatus for a fuel injection engine according to any one of claims 1 to 3, wherein it is determined that the pump operation permission state is reached when a predetermined value is reached.   Voltage detection means (40) for detecting the voltage of the battery (35), wherein the permission signal output means (42) detects that the battery voltage detected by the voltage detection means (40) exceeds a predetermined permission threshold; 4. The control device for a fuel injection engine according to claim 1, wherein it is determined that the pump operation permission state has been reached according to the control.   The permission signal output means (42) determines that the pump operation permission state has been reached when a predetermined time elapses from the prohibition signal output from the prohibition signal output means (41). Item 4. The fuel injection engine control device according to any one of Items 1 to 3.

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