JP2010203294A - Engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable quick start control even if a battery has been completely discharged during an engine stop. <P>SOLUTION: This device determines battery full discharge by ECU start timing itself and immediately start control after that even if a battery voltage is not sufficient when an ignition switch is turned on. Since control for the increase of bypass air quantity and the increase of target engine speed can be started before reaching idling, the engine can be surely started even in an unstable start state caused by an electric load of the vehicle or the like. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine control device, and more particularly to an engine control device mounted on a vehicle having a small battery capacity, such as a motorcycle.

Conventionally, a vehicle is equipped with an electric load that consumes electric power in addition to the engine operating system, which obtains electric power from a battery or a generator that works in conjunction with engine rotation. By the way, when the power generation of the generator is weak, the load on the battery becomes relatively large. Since the capacity of the battery is limited, if the electric power of the battery is consumed by the electric load, the power supply to the ignition system, the fuel system, and the engine control device that integrates them is hindered, which hinders engine operation. May occur.
Therefore, for example, when the battery voltage drops due to a load such as an air conditioner during idling, the bypass air amount is increased and the target idle speed is set high, thereby increasing the power supply amount of the generator and preventing the battery from running out. An engine speed limiter that maintains engine operation is known (for example, Patent Document 1).

JP-A-11-36915

  By the way, the engine speed limiting device according to Patent Document 1 is intended to prevent a battery voltage shortage during idling due to an electric load being applied. Therefore, when the power generation amount before reaching the idling state is small, the influence of the electric load of the vehicle becomes relatively large, and there is a possibility that the electric power necessary for starting the engine may not be sufficiently supplied. In particular, this effect cannot be ignored in the case of a two-wheeled vehicle with a small battery capacity. In addition, the case where the battery has already run out while the engine is stopped was not taken into consideration.

  The present invention has been made in view of the above circumstances, and an object thereof is an engine control device that is particularly effective for a vehicle having a small battery capacity such as a two-wheeled vehicle, and the battery voltage is not sufficient already while the engine is stopped. To provide an engine control device that can reliably start an engine by controlling the amount of bypass air and the engine speed according to the battery voltage even in a state before idling, which is likely to cause power generation shortage due to the electric load of the vehicle, etc. It is in.

  The engine control device of the present invention is a crank that is electrically connected to a battery by an ignition switch and that is activated by a voltage generated by using the rotation of the crankshaft by manual operation or the voltage of the battery and detects the rotation of the crankshaft. In the engine control device that receives a signal from the sensor, when the signal from the crank sensor is detected within a predetermined determination time from the start, it is determined that the engine is started by a voltage generated using the rotation of the crankshaft by manual operation. It is characterized by doing.

  In the engine control apparatus, a predetermined determination time for determining whether or not a signal from a crank sensor after the engine control apparatus is activated is set between 16 milliseconds and 225 milliseconds, and is manually operated. When it determines with having started with the voltage generated using the rotation of a crankshaft, it is further characterized by determining with the battery voltage shortage at the time of connection of an ignition switch.

  In addition, when it is determined that the engine is activated by the voltage generated using the rotation of the crankshaft by manual operation, the amount of air that bypasses the upstream and downstream of the throttle valve disposed in the engine intake pipe is set for a predetermined duration. Set to increase, and set the target engine speed after elapse of a predetermined duration longer than the target engine speed when it is not determined that the engine has been started by the voltage generated using the crankshaft rotation by manual operation. It is characterized by doing.

  According to the engine control device of the present invention, when the engine control device (hereinafter referred to as ECU) is started after the start of cranking by manual operation, it is determined that the start-up voltage of the ECU is generated by the cranking. It can be determined that the battery voltage is insufficient at the time of connection. In the following, the battery voltage shortage state when the ignition switch is connected is defined as battery exhaustion. Since battery exhaustion is determined based on the start timing of the ECU, it is not dependent on processing such as battery voltage detection that is controlled only after the ECU is started, and subsequent engine start and power generation can be controlled from an early timing. It becomes like this.

  By setting the predetermined time from the start of the ECU to the detection of the crank signal between 16 milliseconds and 225 milliseconds, it is not erroneously determined whether or not the battery has run out. Depending on the situation.

  Furthermore, when it is determined that the battery has run out, the engine intake air amount is set to increase for a predetermined duration from a state where the power generation amount before reaching the idle state is low. Can be secured. And since the engine target rotation speed was set large before the predetermined duration time passed, it is possible to prevent the voltage from dropping suddenly due to the electric load already connected as soon as the duration time has passed. Therefore, it is possible to prevent the ECU stop and the engine stall associated therewith.

It is a block diagram containing the engine control apparatus of this invention. (A) is a control flow figure at the time of ECU starting until the battery exhaustion determination of this invention. (B) is a control flow diagram for explaining the battery exhaustion determination of (a). It is a control flowchart showing start control until the engine rotates stably when it is determined that the battery runs out according to the present invention. The difference between the control in the case where it is determined that the battery is exhausted by detecting the crank signal of the present invention within a predetermined determination time and the control in the case where it is not determined is the ECU activation state (a), the ISCV set opening duty ( b) is a timing diagram expressed from time changes at engine start of the engine target speed (c) and the engine speed (d). FIG. 4 is a timing diagram showing engine speed in the present invention as a time change until the engine state is stabilized after the ignition switch is connected.

  An embodiment including an engine control device of the present invention will be described based on FIG.

  The engine 1 in FIG. 1 includes a crank sensor 2 that detects a pulse signal generated according to the rotation of the crankshaft, a generator 4 that generates power by rotating in conjunction with the crankshaft, the temperature of the engine from the coolant temperature, and the like. And an ignition device 15 for igniting the compressed air-fuel mixture in the engine cylinder. The crankshaft starts to rotate by a kick operation, an operation through a recoil starter, a manual operation such as pushing by pushing the vehicle (hereinafter referred to as a kick or the like), or a cell motor 29.

  An intake pipe 5 which is a passage of air taken into the cylinder of the engine includes a throttle valve 8 disposed in the intake pipe 5, a throttle opening sensor 12 for detecting the opening degree, and upstream and downstream of the throttle valve 8. A bypass passage 7 for bypassing the intake pipe 5 and an idle speed control valve (hereinafter referred to as ISCV) 10 for adjusting the amount of bypass air in the bypass passage 7, an actuator (hereinafter referred to as ISC) 9 for duty-driving the opening of the ISCV, an engine An intake pressure sensor 13 that detects negative pressure generated by rotation, an intake air temperature sensor 11 that detects the intake air temperature of the engine, and a fuel injection pump module 14 that inhales fuel by volume change and injects fuel into the intake pipe are arranged. Note that 14 may include an injector that performs only fuel injection. Hereinafter, both are referred to as a fuel injection device 14.

  The exhaust pipe 6 includes an oxygen sensor (not shown) that detects the oxygen concentration in the exhaust gas, an oxygen sensor heater 17 that raises the temperature to stabilize the output characteristics of the oxygen sensor, and NOx in a three-way catalyst installed further downstream. , Secondary air passage 31 for supplying secondary air feedback-controlled to increase the purification rate of HC and CO to the exhaust pipe, and a second air valve (hereinafter referred to as SAV) 16 for adjusting the secondary air in the middle thereof Is placed.

  As a configuration for supplying electric power to each component, a control system power supply for supplying electric power to each control component such as an ignition switch 25 for connecting a battery or a generator as a power source, a fuel injector 14, ISC9, SAV16, an oxygen sensor heater 17, etc. Relay 26, battery 20, battery connection relay 22 that connects the battery to the generator 4, a diode 21 that prevents power supply to the battery when the battery is disconnected, an electrical load 24 such as a lighting device, and an electrical load connection relay that controls the connection 23, a regulator 18, a capacitor 19, a cell switch 30 that supplies power to the cell motor 29, and a starter relay 28.

  An engine control device (hereinafter referred to as ECU) 27 that controls the intake system, exhaust system, and power supply system that constitutes the periphery of the engine as described above receives various sensor outputs such as the crank sensor 2 and controls the amount of bypass air by duty control of ISCV. Settings, setting of the target engine speed of the engine 1, the storage state of the battery 20, connection of each power line, various timing processes, and the like are controlled.

  Based on (a) and (b) of FIG. 2, the control flow of the battery exhaustion determination at the time of ECU activation will be described.

  When the ignition is turned on, the ignition switch 25 is connected, and in step S201 in FIG. 2A, the ECU 27 is activated upon receiving a necessary voltage from the battery or the generator. In order to shorten the time required for starting, in step S202, initialization processing is performed only for items related to engine starting. The initialization process includes, for example, a process for acquiring the engine temperature, a process for switching the operation mode and the fuel injection mode so that the engine can be started, and the like. Items that are not essential for starting the engine are excluded because they are processed after the engine is started in order to shorten the processing steps. Thereafter, in step S203, a battery exhaustion determination is performed.

  Since it is only necessary to determine whether the battery has run out at the time of ECU activation, first, in step S204 of FIG. 2B, it is confirmed from the value of the battery status confirmation flag whether or not the battery status has been confirmed after ECU activation. If not confirmed yet, the process proceeds to step S205, and it is confirmed whether or not a predetermined determination time (for example, about 25 milliseconds) has elapsed after the ECU is activated. If the battery state has already been confirmed, the process proceeds to No in step S204, and the battery state is not confirmed until the ECU is activated again.

  If the elapsed time after ECU activation is less than the determination time, it is determined in step S209 whether the signal from the crank sensor is equal to or higher than the determination voltage. By checking the crank signal due to cranking such as kicking within the judgment time after ECU activation, it is possible to confirm that the power required for ECU activation is supplied for the first time by manual operation such as kicking, and the engine before ignition activation While the vehicle is stopped, it is determined that the battery has not accumulated enough voltage to start the ECU. Here, the processing for calculating the rotational speed is not necessary, and it is only necessary to detect the pulse from the crank sensor, so that it is possible to shorten the control at the start, which requires quick processing. This state is determined as battery exhaustion, the process proceeds to step S207, and the battery exhaustion flag is set to -1 as battery exhaustion.

  Since the battery state has been confirmed by the above processing, the process proceeds to step S208 to set the battery state confirmation flag to 1 and record that the battery state has been confirmed.

  If no crank signal equal to or higher than the determination voltage is detected in step S209, the process returns to step S205. When the elapsed time after starting the ECU reaches the determination time in step S205, the process proceeds to step S206 to determine whether or not the battery voltage is less than a predetermined voltage. If the battery voltage is less than the predetermined voltage, the process proceeds to step S207, where the battery running flag is set to -1, and it is recorded that the battery running is determined.

  If the elapsed time after starting the ECU has reached the determination time and the battery voltage is equal to or higher than the predetermined voltage in step S206, it is determined that the battery is storing a sufficient voltage for starting the engine, and it is not determined that the battery has run out. Proceeding to step S208, the battery state confirmation flag is set to 1, and it is recorded that the battery state is confirmed.

  If it is determined in step S206 that the battery voltage is less than the predetermined voltage, it is determined that the battery voltage cannot withstand engine start, the process proceeds to step S207, and the fact that it is determined that the battery is high is set by setting the battery high flag.

  The lower limit of the determination time in step S205 is preferably 16 milliseconds. If it is less than this lower limit value, even if crank rotation due to kicking or the like has started when the ECU is started, the judgment time will elapse before crank pulse detection after starting, so before cranking such as kicking If the ECU is activated, the battery voltage may be determined to be sufficient when the ignition is turned on. Since the number of rotations due to kicking or the like is 300 rpm at the maximum, the number of crank teeth is 24, and the crank pulse interval is about 8 milliseconds. The lower limit value is about 16 milliseconds so that the pulse interval can be detected even at a position where it is doubled due to missing teeth.

  The upper limit value of the determination time in step S205 is preferably 225 milliseconds. If this upper limit is exceeded, even if the battery voltage at the time of ignition ON is insufficient, the battery voltage may increase due to the engine rotation by the cell motor before the process of step S206. In step S206, it is determined that the battery is high. There is a risk of disappearing. In addition, although the ignition is turned on with the battery voltage sufficient, the timing of a general kick or the like is determined to be within the determination time in step S209, and it may be determined that the battery is running out.

  With the above control, it is possible to determine whether or not the battery is exhausted before starting the engine based on the start timing of the ECU, so that the time required for starting the engine can be shortened. As a result, since the process after it is determined that the battery has run out can be moved forward, the control at the time of starting can be executed promptly.

  For example, processing such as calculating the number of rotations due to an operation such as kicking to determine the generated voltage is not required, so that measurement of the pulse interval and calculation of the number of rotations at the initial stage of start control as in step S209 are not required. . Even if the ignition is turned on while the battery is not charged with a voltage corresponding to the start-up voltage of the ECU, if the operation such as kicking for one crank tooth is performed, the control after determining that the battery has run is started. be able to.

  Next, the engine start control when it is determined that the battery has run out will be described with reference to FIG.

  If the battery state is confirmed in step S301, it is confirmed in step S302 whether it is determined that the battery has run out. If it is determined that the battery has run out, the SAV control and power supply to the oxygen sensor heater are stopped in step S303 so as not to impair the power required for starting the engine. In step S304, the engine target speed N1 (N1> N2) is set. For example, it is set to 1800 rpm (N1) with respect to 1500 rpm (N2) when it is not determined that the battery has run out. And the duty which determines the basic opening of ISCV is increased. In step S305, the duty of the ISCV is set to be increased. In step S306, after waiting for the lapse of the duration p1 from the start of the ECU, feedback control corresponding to the engine state is performed in step S307. Even when it is determined that the battery has run out, the setting of p1 is about 800 rpm so that sufficient rotation to obtain a generated voltage can be secured by ignition control by the ignition device 15 and injection control by the fuel injection device 14. It is preferably about 500 milliseconds corresponding to 3 or 4 engine cycles when the engine rotates.

  On the other hand, if it is not determined in step S302 that the battery has run out, the engine target speed is set to N2 (N2 <N1) in step S308. For example, it is set to 1500 rpm (N2) with respect to 1800 rpm (N1) when it is determined that the battery has run out. In step S309, the ISCV duty is increased, and in step S310, after waiting for the time p2 (p2 <p1) to increase to, for example, 1100 rpm, feedback control corresponding to the engine state is performed in step S307.

  With the control based on FIGS. 2 and 3 described above, the engine start control is performed in accordance with the battery exhaustion determination. In addition, the pumping loss at the time of engine starting can also be suppressed by increasing the ISCV duty in steps S306 and S310.

  Thereafter, parameters that are not essential for starting the engine, such as long-term learning values that have not been processed in ECU initialization (step S202), are read from the EEPROM. Therefore, the control until the engine is started can be processed quickly.

  As described above, the determination time is preferably set between 16 milliseconds and 225 milliseconds.

  When the determination time exceeds the upper limit of 225 milliseconds, the battery voltage rises before the process of determining whether the battery voltage is sufficient even though the ignition switch is connected with the battery voltage being insufficient. There is a risk of misunderstanding that the battery voltage is sufficient. Further, there is a possibility that a crank signal due to a kick at a general timing or the like may be mistaken as a crank signal during cranking, even though the battery while the engine is stopped has a voltage that can withstand engine start. On the other hand, if the determination time is less than the lower limit of 16 milliseconds and the crank pulse interval at the time of cranking is longer than that, the ECU has been started before cranking despite being started during cranking. There is a risk of misunderstanding. Because of these misidentifications, the control according to the battery state is not properly selected, so it is preferable to set the upper and lower limits of the determination time as described above.

  Based on FIG. 4, the ECU activation state (a), ISCV is the difference between the control in the case where the crank signal is detected within a predetermined determination time and the control in the case where it is determined that the battery is out. A description will be given based on changes in the set opening duty (b), the target engine speed (c), and the engine speed (d) over time when the engine is started. A solid line indicates a case where it is determined that the battery is running out, and a dotted line indicates a case where it is not determined that the battery is running out. Note that the overlapping portion is indicated by a solid line.

  At t0, an ignition switch is connected, and a power supply system such as a battery or a generator is connected to the ECU. At t1, when the engine speed gradually increases due to cranking by kick or the like, and the generated voltage satisfies the ECU activation voltage, the ECU is activated at t2. If it is determined that the battery is running out at t3, N1 is set to be larger than the target rotational speed N2 when it is not judged that the battery is running out. At this time, the ISCV duty is set to increase, and the engine is started at t4. Thereafter, at t5 after elapse of p1 from t3, the ISCV duty is feedback controlled according to the engine state.

  On the other hand, if the battery voltage is sufficient and it is not determined that the battery is running out, the ECU is activated at t2 'earlier than the kick or the like. The ISCV duty is set to increase from time t3 ', and the engine is started earlier than t4. Thereafter, when t2 after p2 has elapsed, the ISCV duty is feedback-controlled according to the engine state. Although t3 'is after cranking start, it may be before cranking start depending on the battery state.

  Based on FIG. 5, the engine state at the start when it is determined that the battery is running will be described. The engine speed at which the control of the present invention is implemented is represented by a solid line, and the engine speed by conventional control that is not the present invention is represented by a two-dot chain line. The engine speed when the electric load of the vehicle consumes electric power during normal control is indicated by alternate long and short dash lines L1 and L2. In addition, the description which overlaps with FIG. 4 is abbreviate | omitted.

  If it is determined that the battery is running off at t3, if the ISCV set duty is increased, the power generation amount at t4 when the engine starts increases faster than in the normal control represented by the two-dot chain line. At this time, if the increase in the ISCV setting duty is not continued only during p1, the rotational speed becomes unstable as shown by the one-dot chain line L2 due to the influence of the electric load, which may cause an engine stall or the like. Also, if the engine target speed is set to a large value before t5 when the ISCV set duty is returned to the feedback control state, the generated voltage is generated by an electric load such as a one-dot chain line L2 as soon as the ISC returns to the feedback control. The phenomenon of being depressed can be prevented. As described above, even when the engine is unstable at the time of engine start, ECU stop and engine stall due to power shortage can be avoided, so that stable engine control can be continuously performed immediately after starting.

  It should be noted that after the warm-up at the start of the engine is sufficiently performed, feedback control is performed according to the engine target speed lower than N2.

  As described above, even if the battery voltage is insufficient when the ignition is turned on, the battery start determination is performed at the ECU activation timing itself, so that the subsequent start control is started quickly, and the increase in the bypass air amount and the engine target Since the control for increasing the number of revolutions can be started before reaching idling, a reliable start can be achieved even in the unstable start state due to the electric load of the vehicle.

  The present invention is particularly effectively applied to a vehicle having a small battery capacity among two-wheeled vehicles that can start an engine by a manual operation such as a kick.

4 Generator 7 Bypass passage 8 Throttle valve 9 ISC (idle speed control actuator)
10 ISCV (idle speed control valve)
14 Fuel injection device 15 Ignition device 16 SAV (second air valve)
17 Oxygen sensor heater 20 Battery 21 Diode 22 Battery connection relay 23 Electric load connection relay 24 Electric load 25 Ignition switch 27 ECU (Engine control device)

Claims (3)

It is electrically connected to the battery by the ignition switch,
It is activated by the voltage generated using the rotation of the crankshaft by manual operation or the voltage of the battery,
In an engine control device that receives a signal from a crank sensor that detects rotation of the crankshaft,
An engine control device that determines that the engine is activated by a voltage generated by using rotation of a crankshaft by the manual operation when a signal from the crank sensor is detected within a predetermined determination time from activation. The predetermined determination time is set between 16 milliseconds and 225 milliseconds;
2. The engine according to claim 1, wherein when it is determined that the battery is started by a voltage generated using rotation of the crankshaft by the manual operation, the battery voltage is insufficient when the ignition switch is connected. 3. Control device. When it is determined that the operation is started by the voltage generated using the rotation of the crankshaft by the manual operation,
The amount of air that bypasses the upstream and downstream of the throttle valve disposed in the engine intake pipe is set to increase for a predetermined duration, and the target engine speed after the lapse of the predetermined duration is set to the crankshaft by the manual operation. The engine control device according to claim 1 or 2, wherein the engine control device is set to be larger than a target engine speed when it is not determined that the engine is started by a voltage generated by using rotation.

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