JP2009036057A - Eco-run control device - Google Patents

Abstract

It is an object of the present invention to provide an eco-run control device that can restart an engine at an early stage and appropriately control a fuel injection amount at the time of restart.
An eco-run in which an engine is stopped based on establishment of a predetermined stop condition, and thereafter a starter is driven by power supply from a battery based on establishment of a predetermined start condition to restart the engine. When the engine 10 is restarted, the starter 51 is driven during the effective injection period after the invalid injection period of the injector 43 driven by the power supply from the battery 52 has elapsed.
[Selection] Figure 5

Description

  The present invention relates to an eco-run control device.

  Conventionally, for the purpose of improving fuel consumption and reducing gas exhaust amount, so-called eco-run control devices are known in which an engine is stopped when a predetermined stop condition is satisfied, and then the engine is restarted when a predetermined start condition is satisfied. Yes. In such an eco-run control device, it is desired to be restarted early after the engine is stopped. In order to restart the engine early, it is necessary to inject fuel before driving the starter. A technique for injecting fuel before driving the starter is disclosed in Patent Document 1.

Japanese Patent Laid-Open No. 5-149221

  In order to restart the engine earlier, it is necessary to drive the starter earlier. However, for example, when the starter is driven during the invalid injection period of the injector, the injector and the starter are driven by electric power supplied from a common battery, so that the invalid injection period of the injector is prolonged and the effective injection period is increased. There is a risk of shortening. In such a case, there is a possibility that the fuel injection amount becomes smaller than an assumed amount, and it may be difficult to appropriately control the fuel injection amount at the time of restart.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an eco-run control device that can restart the engine early and can appropriately control the fuel injection amount at the time of restart.

The above-described object is an eco-run control device that stops an engine based on establishment of a predetermined stop condition, and then restarts the engine by driving a starter by power supply from a battery based on establishment of a predetermined start condition. An eco-run control device that drives the starter during an effective injection period after an invalid injection period of an injector driven by power supply from the battery when the engine is restarted. Can be achieved.
When the starter is driven during the invalid injection period, the voltage of the battery is lowered by driving the starter, and therefore the invalid injection period of the injector is prolonged. For this reason, the effective injection period is shortened and the fuel injection amount is insufficient. However, it is possible to suppress the lengthening of the invalid injection period by driving the starter during the effective injection period after the invalid injection period has elapsed. Thereby, the engine can be restarted at an early stage, and the fuel injection amount at the time of restart can be controlled appropriately.

The said structure WHEREIN: The structure which changes the timing which drives the said starter according to the pressure of the fuel supplied to the said injector is employable.
When the fuel pressure is low, the invalid injection period tends to be short, and when the fuel pressure is high, the invalid injection period tends to be long. Therefore, for example, when the fuel pressure is lower than a predetermined value, the starter can be driven earlier than when the fuel pressure is higher than a predetermined value. Thereby, the engine can be restarted earlier.

The said structure WHEREIN: The structure which changes the timing which drives the said starter according to the voltage of the said battery is employable.
When the battery voltage is high, the invalid injection period is shortened, and when the battery voltage is low, the invalid injection period tends to be long. Therefore, for example, when the battery voltage is higher than a predetermined value, the starter can be started earlier than when the battery voltage is lower than the predetermined value. Thereby, the engine can be restarted earlier.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to restart an engine early, the eco-run control apparatus which can control appropriately the fuel injection quantity at the time of restart can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of an engine system in which an eco-run control device according to the present invention is employed. The engine system stops the engine based on the establishment of a predetermined stop condition, and then operates an eco-run control mode in which the starter is driven by power supply from a battery based on the establishment of the predetermined start condition to restart the engine. It is feasible.

  The engine system includes an engine 10, an engine electronic control device (hereinafter referred to as an engine ECU) 21, an eco-run electronic control device (hereinafter referred to as an eco-run ECU) 22 that is an eco-run control device, and ABS (anti-skid brake system) electronics. It comprises a control device (hereinafter referred to as a brake ECU) 23 and the like.

  The engine 10 is provided with an alternator 54 and a starter 51, and power is supplied from the battery 52 to the starter 51. In addition, power is supplied from the battery 52 to the auxiliary load 53 which is an in-vehicle device such as accessories.

  The engine ECU 21 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, performs processing such as calculation based on various input signals, and sends various signals to the engine 10 and the eco-run ECU 22. Is output.

  More specifically, the engine ECU 21 receives signals related to accelerator on / off, accelerator opening, shift position sensor 34 from AT shift position, crank angle sensor 35 from engine speed, and the like. Further, an engine stop command signal and an engine restart command signal output from the eco-run ECU 22 are input to the engine ECU 21.

  The brake ECU 23 includes a CPU, a ROM, and a RAM, like the engine ECU 21, and receives signals such as a brake master pressure from the brake master pressure sensor 31 and a vehicle speed from the vehicle speed sensor 32.

  Similar to the engine ECU 21, the eco-run ECU 22 includes a CPU, a ROM, and a RAM. The eco-run ECU 22 automatically stops and restarts the engine in the eco-run control mode based on a status signal indicating the state of each part of the engine drive system. Output various command signals.

  More specifically, the eco-run ECU 22 receives status signals representing statuses such as a fuel injection state, an intake air amount state, and an ignition state that are output from the engine ECU 21. In addition, a brake pressure signal output from the brake master pressure sensor 31, a vehicle speed signal input from the vehicle speed sensor 32, an accelerator on / off signal input from the accelerator SW 33, and the like are input.

  Further, the eco-run ECU 22 outputs to the engine ECU 21 an engine stop command signal for performing eco-run control and an engine restart command signal for restarting the engine. As a result, the engine ECU 21 outputs control signals such as fuel injection, intake air, and ignition control to the engine 10. Further, the eco-run ECU 22 outputs a restart starter control signal to the starter 51 when the engine is restarted.

  Each cylinder 11 of the engine 10 is provided with an injector 43 for injecting fuel into each cylinder 11. The injector 43 injects fuel accumulated in the common rail 42 into each cylinder 11. In the common rail 42, the fuel pumped from the fuel tank (not shown) via the fuel rail 41 is accumulated.

  The fuel pressure sensor 36 is disposed in the fuel rail 41, detects the fuel pressure of the fuel passing through the fuel rail 41 (hereinafter referred to as fuel pressure), and outputs it to the eco-run ECU 22. The fuel pressure sensor 36 also outputs the detected signal to the engine ECU 21. The battery voltage sensor 37 detects the voltage of the battery 52 and outputs it to the eco-run ECU 22.

  Next, the configuration of the injector 43 will be briefly described. The injector 43 includes a solenoid coil (not shown) and a valve body driven by the solenoid coil, and is configured such that the valve body is pulled up and opened by energization of the solenoid coil by power supply from the battery 52. ing. When the valve body is pulled up, fuel is injected.

  A process when the engine is automatically stopped when a predetermined automatic stop condition is satisfied will be described. The automatic stop conditions are, for example, (a) the vehicle speed is zero or below a predetermined value, (b) the shift position is a drive position, and (c) the brake master pressure is above a predetermined value. When set and all conditions are met, the engine is automatically stopped.

  When the eco-run ECU 22 determines that the conditions (a) to (c) are satisfied, the eco-run ECU 22 outputs an engine stop command signal to the engine ECU 21. As a result, the engine ECU 21 outputs to the engine 10 a fuel injection signal for cutting the supply of fuel to the engine and an intake signal for cutting intake air to the engine. When there is no fuel injection or intake, the engine 10 automatically stops. When the engine 10 is automatically stopped, the eco-run ECU 22 turns on and holds a flag indicating that the engine has been automatically stopped.

  Next, processing when the engine 10 is automatically stopped and restarted when a predetermined restart condition is satisfied will be described. First, it is determined based on the flag whether or not it is an automatic stop. If the engine is not automatically stopped, the restart process is not performed so that the engine is not automatically started. If the brake is automatically stopped, then the brake master pressure is monitored. If the foot brake is fully depressed, the automatic stop is continued.

  When the foot brake is not fully depressed, (x) the brake master pressure is continuously monitored. For example, when the foot brake is not depressed even after a predetermined time has elapsed, (y) the accelerator opening degree by the accelerator SW 33 When the accelerator is depressed more than a predetermined value by monitoring the signal, (z) When the vehicle speed signal by the vehicle speed sensor 32 is monitored and the vehicle speed exceeds the predetermined value, it is determined that the driver intends to drive Then, engine restart control is performed.

  In the engine restart control, the eco-run ECU 22 outputs an engine restart command signal to the engine ECU 21 and outputs a starter control signal to the starter 51. As a result, the engine ECU 21 outputs control signals for fuel injection, intake air, and ignition control to the engine 10, and the engine ECU 21 drives the starter 51 at a predetermined timing. As a result, the engine 10 is restarted.

  Next, the relationship between the voltage of the battery 52 and the invalid injection period will be described. FIG. 2 is an explanatory diagram of the relationship between the voltage of the battery 52 and the invalid injection period. The invalid injection period is a period that does not contribute effectively to fuel injection due to a response delay of the injector 43. As shown in FIG. 2, when the voltage of the battery 52 decreases, the invalid injection period becomes longer. This is because when the voltage of the battery 52 decreases, the period during which the injector 43 shifts from the closed state to the open state becomes longer than when the voltage of the battery 52 does not decrease. Thereby, during the transition period, the injector 43 does not contribute effectively to fuel injection, and the invalid injection period is prolonged.

  For example, if the voltage of the battery 52 in the normal state is 12V, the battery voltage when the starter 51 is driven is lower than 12V. When the voltage of the battery 52 is lowered due to the starter 51 being driven, if the injector 43 is shifted from the valve closing state to the valve opening state, the invalid injection period is prolonged.

  When the injector 43 transitions from the valve-opened state to the valve-closed state, the valve body is closed by the urging force of the spring that urges the valve body in the valve-closing direction. The transition period to the state is not affected by the voltage of the battery 52.

  Next, the drive timing of the conventional starter when the engine is restarted will be described. FIG. 3 is a chart showing the drive timing of a conventional starter when the engine is restarted. When a drive signal is output from the engine ECU 21 to the injector 43, the injector 43 shifts from the valve closing state to the valve opening state with an invalid injection period that is a response delay period. The injection time after the invalid injection period has elapsed and effectively contributing to fuel injection is defined as the effective injection period. When the output of the drive signal from the engine ECU 21 to the injector 43 is stopped, the injector 43 shifts from the valve opening state to the valve closing state with a predetermined response delay period. In the conventional starter drive timing, the eco-run ECU 22 outputs a drive signal to the starter 51 after the injector 43 reaches the valve closing state. Further, when the drive signal is output to the starter 51, the voltage of the battery 52 temporarily decreases rapidly, and during the output of the drive signal to the starter 51 (that is, while the starter 51 is being driven) Compared with the case where 51 is not driven, the voltage of the battery 52 is maintained in a lowered state.

  As shown in FIG. 3, the drive timing of the conventional starter was driven after the fuel injection was completed. For this reason, the engine could not be restarted early.

  Next, the case where the starter drive timing is during the invalid injection period when the engine is restarted will be described. FIG. 4 is a timing chart when the starter drive timing is during the invalid injection period when the engine is restarted. When a drive signal is output to the starter 51 during the invalid injection period, the voltage of the battery 52 decreases during this period. Thereby, the response delay period of the drive of the injector 43 is prolonged. Accordingly, the invalid injection period is prolonged. In such a case, the effective injection period is shortened and the fuel injection amount is insufficient. Therefore, it is not possible to appropriately control the fuel injection amount when the engine 10 is restarted.

  If the starter 51 is driven before the invalid injection period, that is, before the drive signal is output to the injector 43, the starter 51 is being driven during the invalid injection period. Ineffective injection period is prolonged.

  Next, the drive timing of the starter in the eco-run control device according to the present invention when the engine is restarted will be described. FIG. 5 is a timing chart regarding the starter drive timing in the eco-run control device according to the present invention at the time of engine restart. As shown in FIG. 5, the eco-run ECU 22 outputs a drive signal to the starter 51 during the effective injection period after the invalid injection period has elapsed. Thereby, the lengthening of the invalid injection period can be suppressed. Therefore, the engine can be restarted at an early stage, and the fuel injection amount at the restart can be appropriately controlled.

  Next, engine restart control executed by the engine ECU 21 and the eco-run ECU 22 will be described. FIG. 6 is a flowchart showing an example of engine restart control executed by the engine ECU 21, and FIG. 7 is a flowchart showing an example of engine restart control executed by the eco-run ECU 22. The engine ECU 21 and the eco-run ECU 22 each determine whether there is a request for engine restart (steps S11 and S21). For example, when the accelerator opening signal is monitored by the accelerator SW 33 during the automatic stop of the engine 10 and the accelerator is depressed more than a predetermined amount, it is determined that there is a request for engine restart. If the determination is negative, this control is terminated.

  If the determination is affirmative, the engine ECU 21 calculates the injection timing of the injector 43 (step S12). Specifically, the injection timing of each injector 43 is calculated based on the output from the crank angle sensor 35.

  The eco-run ECU 22 calculates the timing for driving the starter 51 (step S22), and outputs this timing to the engine ECU 21 (step S23).

  Next, the engine ECU 21 receives the timing for driving the starter 51 from the eco-run ECU 22 (step S13), and determines whether or not the invalid injection period of the injector 43 and the timing for driving the starter 51 overlap (step S14). If the determination is negative, this process ends. That is, the engine ECU 21 and the eco-run ECU 22 drive the fuel injection and starter 51 at the injection timing and starter drive timing calculated in steps S12 and S22. If the determination is affirmative, the engine ECU 21 outputs a delay signal for delaying the timing at which the eco-run ECU 22 drives the starter 51 (step S15).

  The eco-run ECU 22 determines whether or not there is a delay request output from the engine ECU 21 (step S24). If the determination is negative, this process ends. If the determination is affirmative, the eco-run ECU 22 delays the drive timing of the starter 51 (step S25). Specifically, the timing is delayed so that the starter 51 is driven during the effective injection period after the invalid injection period has elapsed. The starter 51 is driven at that timing (step S26). Thereby, it is possible to prevent the starter 51 from being driven during the invalid injection period.

  Next, a modified example of the drive timing of the starter in the eco-run control device according to the present invention at the time of engine restart will be described. FIG. 8 is a timing chart according to a modified example of the drive timing of the starter when the engine is restarted. The eco-run ECU 22 changes the drive timing of the starter 51 during the effective injection period based on outputs from the fuel pressure sensor 36 and the battery voltage sensor 37. For example, when the fuel pressure is lower than a predetermined value, the eco-run ECU 22 drives the starter 51 earlier than when the fuel pressure is higher than a predetermined value. This is because the fuel pressure acts so as to close the valve body of the injector 43. Therefore, when the fuel pressure is low, the invalid injection period is shortened, and when the fuel pressure is high, the invalid injection period tends to be prolonged. Because there is. Therefore, when the fuel pressure is lower than the predetermined value, the engine 10 can be restarted earlier by driving the starter 51 early.

  When the voltage of the battery 52 is higher than a predetermined value, the eco-run ECU 22 starts the starter 51 earlier than when the voltage of the battery 52 is lower than the predetermined value. This is because the invalid injection period tends to be shortened when the voltage of the battery 52 is high, and the invalid injection period tends to be prolonged when the voltage of the battery 52 is low. Therefore, when the voltage of the battery 52 is high, the engine 10 can be restarted earlier by driving the starter 51 early.

  FIG. 9 is a flowchart according to a modified example of the engine restart control executed by the eco-run ECU 22. The engine restart control executed by the engine ECU 21 is the same as that shown in FIG. As shown in FIG. 9, in the case of an affirmative determination in step S24, the eco-run ECU 22 detects the fuel pressure from the fuel pressure sensor 36 and the voltage of the battery 52 from the battery voltage sensor 37 (step S24a). In accordance with the detection result, the eco-run ECU 22 delays the drive timing of the starter 51 (steps S25 and S26). As described above, the eco-run ECU 22 changes the drive timing of the starter 51 according to the fuel pressure and the voltage of the battery 52.

  The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

It is the figure which showed the whole structure of the engine system by which the eco-run control apparatus which concerns on this invention was employ | adopted. It is explanatory drawing of the relationship between the voltage of a battery, and an invalid injection period. It is a chart figure about the drive timing of the conventional starter at the time of engine restart. 6 is a timing chart when the starter drive timing is during an invalid injection period when the engine is restarted. It is a timing chart about the drive timing of the starter in the eco-run control device concerning the present invention at the time of engine restart. It is the flowchart which showed an example of the engine restart control which engine ECU performs. It is the flowchart which showed an example of the engine restart control which eco-run ECU performs. It is a timing chart which concerns on the modification of the drive timing of a starter at the time of engine restart. It is a flowchart which concerns on the modification of the engine restart control which eco-run ECU performs.

Explanation of symbols

10 Engine 21 Engine ECU
22 Eco-run ECU (Eco-run control device)
36 Fuel pressure sensor 37 Battery voltage sensor 43 Injector 51 Starter 52 Battery

Claims (3)

An eco-run control device that stops the engine based on establishment of a predetermined stop condition and then restarts the engine by driving a starter by power supply from a battery based on establishment of a predetermined start condition,
An eco-run control device, wherein when the engine is restarted, the starter is driven during an effective injection period after an invalid injection period of an injector driven by power supply from the battery.   The eco-run control device according to claim 1, wherein a timing for driving the starter is changed according to a pressure of fuel supplied to the injector.   The eco-run control device according to claim 1, wherein a timing for driving the starter is changed according to a voltage of the battery.

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