JP5113435B2 - Fuel pump control device - Google Patents

Description

The present invention relates to a fuel pump system GoSo location for controlling the fuel pump for pumping fuel to the engine.

  In general, in a fuel system of an engine, a fuel pump that supplies fuel from a fuel tank to a carburetor or a fuel injection mechanism that supplies fuel to the engine is provided. The fuel pump is normally controlled by a fuel injection control mechanism so as to be driven in a constant state so as to ensure a discharge amount corresponding to the maximum fuel consumption at the time of high engine load.

  When the fuel injection control mechanism controls the fuel pump to simply correspond to the fuel demand flow rate (engine load) of the engine, the engine load increases rapidly as in the acceleration operation, and the fuel demand flow rate (fuel consumption amount) ) May cause a shortage of fuel when it increases correspondingly.

  On the other hand, for example, in Patent Document 1, in order to prevent a temporary drop in fuel pressure due to a delay in fuel supply response and a decrease in the amount of fuel supplied to the engine, Discharge fuel amount calculation means for calculating the fuel discharged from the fuel pump required at full load for each rotation speed, and the fuel pump discharges substantially the same amount of fuel as the discharge fuel amount calculated by the discharge fuel amount calculation means. A control device for a fuel pump provided with control means for controlling in this way is disclosed.

  In general, the fuel flow rate that can be supplied to the fuel pump may be insufficient with respect to the increase in the required fuel flow rate of the engine. As conventional countermeasures for solving this problem, the following measures are conceivable.

  First, it is conceivable to arrange a large-capacity type fuel pump that satisfies the required fuel flow rate of the engine.

  Secondly, it is conceivable to install two fuel pumps that have been used in the past so that the required fuel flow of the engine is satisfied, and to drive the two fuel pumps simultaneously.

Thirdly, in a so-called V-type engine in which cylinders are arranged to face each other in a V shape, it is conceivable to arrange a fuel pump in each bank (inclined surface).
Japanese Patent No. 284005 (paragraphs 0007 to 0010, FIG. 1)

  However, in the technical idea disclosed in Patent Document 1, it is necessary to provide a discharge fuel amount calculation means for calculating the discharge fuel of the fuel pump required at the time of full load of the internal combustion engine in the control device, and the control method is complicated. In addition, there is a problem that the control device is enlarged.

  In addition, in the first countermeasure for installing a large flow rate type fuel pump, there is a problem that the manufacturing cost increases because the types of large flow rate type fuel pumps sold as off-the-shelf products are rare. In addition, there is another problem that power consumption and heat generation increase with an increase in fuel demand flow rate, and vibration and noise characteristics deteriorate.

  Next, in the second countermeasure in which two fuel pumps are installed and driven simultaneously, a control mechanism for controlling the two fuel pumps at the same time becomes complicated, and a pump module including two fuel pumps is provided. There is a problem that it becomes special and it is not easy to make a general-purpose product. In addition, there is another problem that power consumption and heat generation increase with an increase in fuel demand flow rate, and vibration and noise characteristics deteriorate.

  Subsequently, in the third countermeasure in which a fuel pump is arranged for each bank (inclined surface) in a so-called V-type engine, the control mechanism becomes complicated, and the fuel that has failed among the plurality of installed fuel pumps. There is a problem that trouble diagnosis is difficult for the pump to determine either. In addition, there is another problem that power consumption and heat generation increase with an increase in fuel demand flow rate, and vibration and noise characteristics deteriorate.

  Further, it is assumed that the fuel pump discharge flow rate is controlled so as to satisfy the required fuel flow rate of the engine by changing the fuel pressure using a variable fuel pressure system. However, the control system constructed in this way has a problem that it is complicated and the manufacturing cost increases.

The present invention has been made in view of the various problems mentioned above, simple to satisfy the fuel flow rates demanded engine by a mechanism, yet the fuel pump system GoSo location capable of achieving reduction in manufacturing cost The purpose is to provide.

According to the present invention, the rated flow rate of the fuel pump is set in advance based on the standard life when the voltage applied to the DC electric motor is constant and continuously operated. When the voltage control means determines that the required flow rate of the fuel required by the engine based on the engine load exceeds the set rated flow rate of the fuel pump, the voltage control means sets the applied voltage to a predetermined voltage equal to or higher than the rated voltage. Boost to voltage. The fuel pump is controlled so as to supply a flow rate exceeding the rated flow rate to the engine by energizing a DC electric motor with the boosted applied voltage. On the other hand, when it is determined that the required flow rate of the engine is not more than the rated flow rate after boosting the applied voltage , the boosting is stopped and the discharge flow rate of the fuel pump is controlled to the normal use flow rate.

  As described above, in the present invention, when the load on the engine suddenly increases, the pump driving voltage is boosted to a predetermined voltage equal to or higher than the rated voltage via the voltage control means, so that the fuel corresponding to the engine load is supplied to the engine. Can be suitably supplied. As a result, in the present invention, the required fuel flow rate of the engine can be satisfied by a simple mechanism, and the manufacturing cost can be reduced.

Further , in the present invention, the storage means for storing the time when the fuel pump is driven exceeding the rated flow rate, and the standard when the applied voltage applied to the DC electric motor is continuously operated with a constant driving time. Processing means for stopping the supply of fuel exceeding the rated flow rate and notifying the driver that the supply of fuel exceeding the rated flow rate has been stopped when a preset time is reached in consideration of the service life. By further providing, it is possible to prevent the durability of the fuel pump from deteriorating and to efficiently use the fuel.

  In the present invention, when the load on the engine suddenly increases, the required fuel flow rate of the engine can be satisfied by a simple mechanism that boosts the pump drive voltage to a predetermined voltage higher than the rated voltage, and a pump with a lower rated flow rate can be used. As a result, reductions in manufacturing cost and power consumption can be achieved.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. Figure 1 is a schematic block diagram of a fuel pump system GoSo location according to an embodiment of the present invention.

  An automobile engine 10 functioning as an internal combustion engine has a cylinder block (not shown) provided with a combustion chamber, and an intake passage 12 for sucking an air-fuel mixture through an intake valve (not shown) and a combustion chamber. An exhaust passage 14 for exhausting the combustion gas generated in the combustion chamber to the outside through the exhaust valve is connected in communication.

  The engine 10 is provided with an intake port (not shown), and a fuel injection valve (fuel injector) 16 for injecting fuel toward the intake port is connected in communication. A fuel pump 22 for sucking fuel in the fuel tank 20 is connected to the upstream side of the fuel injection valve 16 via a feed pipe 18, and downstream of the fuel pump 22 upstream of the fuel injection valve 16. A pressure regulator 26 is connected to the side via a return pipe 24. As shown in FIG. 1, since the pressure regulator 26 is provided in the fuel tank 20, the return pipe 24 between the pressure regulator 26 and the fuel tank 20 becomes unnecessary, and the piping structure can be simplified. Can be planned.

  The pressure regulator 26 is for adjusting the fuel injection pressure injected from the fuel injection valve 16 toward the intake port side at a constant level and returning surplus fuel to the fuel tank 20. In this case, for example, the return pipe 24 is not required by disposing the unit in which the pressure regulator 26 is integrally assembled with the fuel pump 22 in the fuel tank 20, thereby further simplifying the piping structure. Can be planned.

  As shown in FIG. 1, the fuel pump control device 30 includes, for example, a battery 32 composed of a DC power source with a rated voltage of 12 V, a DC motor 34 that functions as a DC electric motor energized by the battery 32, and the DC motor. The fuel pump 22 that is driven by the fuel tank 34 and discharges the fuel sucked from the fuel tank 20 toward the engine 10 side, and the applied voltage applied to the DC motor 34 are controlled to control the engine 10 from the fuel pump 22. And a fuel pump control unit 36 that controls the discharge flow rate of the fuel discharged toward the side.

  The DC motor 34 is composed of a rotor (armature) and a stator (permanent magnet) (not shown), and utilizes repulsive force and attractive force of magnetic force generated by switching the direction of current supplied to the rotor. It will rotate. By using the DC motor 34, the rotation control can be easily performed, a large driving torque can be obtained, the rotation characteristic with respect to the applied voltage is linearly proportional, and the cost is low. is there.

  Further, the fuel pump control device 30 is provided with an ECU (Electronic Control Unit) 38 that sends a control signal for controlling the discharge flow rate from the fuel pump 22 to the fuel pump control unit 36. On the input side of the ECU 38, a discharge flow rate sensor 40 for detecting the discharge flow rate of the fuel actually discharged from the fuel injection valve 16 toward the intake port side, a rotation speed sensor 42 for detecting the engine rotation speed, A throttle opening sensor 44 that detects the valve opening of a throttle valve (not shown) that adjusts the flow rate of intake air that is introduced into the combustion chamber in conjunction with the depression of an accelerator pedal (not shown), and the accumulation of the boosted state as will be described later And a warning lamp 48 for notifying the driver that the time has exceeded a predetermined time set in advance. The ECU 38 and the fuel pump control unit 36 function as fuel pump control means. The discharge flow rate sensor 40 also has a function as an FI (Fuel Injection) -ECU. The warning light 48 constitutes a part of the processing means.

  The fuel pump control unit 36 is provided with a DC-DC converter 46 that functions as voltage control means for boosting a pump drive voltage for driving the fuel pump 22 to a predetermined voltage equal to or higher than the rated voltage of the battery 32.

  As the DC-DC converter 46, for example, direct current is converted into alternating current using an IC chip (not shown), transformed to a desired alternating voltage with a variable transformer (not shown), and further converted into direct current for voltage control. There is something. In addition, a non-insulated DC that does not use the transformer, drives the input DC voltage on / off by a switching element (not shown) to form a desired pulse voltage, and rectifies and smooths the formed pulse voltage. A DC converter 46 may be used.

  Further, as the DC-DC converter 46, for example, there is a step-up / step-down automatic switching control circuit (not shown), and the boosting operation and the step-down operation are automatically performed according to the relationship between the input voltage, the output voltage, and the output current. A device that obtains an output voltage by switching inside the chip may be used.

  Furthermore, as the DC-DC converter 46, an inverting DC-DC converter in which the input and output are coupled by a capacitor (not shown) may be used. In this inverting type DC-DC converter, a hysteresis control system is adopted, and the operation of each switching element is controlled so that a current flowing through an inductance (not shown) on the output side is within a preset upper and lower limits. .

  The voltage control means for controlling the pump drive voltage is not limited to the DC-DC converter 46. For example, a reactor (iron core) (not shown) that accumulates and boosts magnetic energy using inductive reactance. And the like. Further, by using not only a direct current motor but also a brushless motor, an alternating current (AC) motor, or the like as a drive source for driving the fuel pump 22, it is possible to similarly control the flow rate above the rated flow rate.

Fuel pump system GoSo location 30 according to this embodiment is intended to be constructed basically as described above, it will be explained the basic operation below.

  The ECU 38 is energized when an ignition switch (not shown) is turned on. The ECU 38 derives a motor control signal to the fuel pump control unit 36, and the DC motor 34 is rotationally driven by a predetermined voltage (within the rated voltage range of the battery 32) applied from the battery 32. The fuel pump 22 is operated by the rotational drive of the DC motor 34, and the fuel sucked from the fuel tank 20 through the feed pipe 18 is discharged from the fuel pump 22 to the fuel injection valve 16.

  When the pressure of the fuel discharged from the fuel pump 22 to the fuel injection valve 16 exceeds a predetermined pressure, a valve (not shown) of the pressure regulator 26 is opened, and excess fuel is returned to the fuel tank 20 via the return pipe 24. It is.

  In the present embodiment, during steady operation, the discharge flow rate of the fuel pump 22 is controlled at a normal use flow rate that is within the rated flow rate range of the fuel pump 22 and corresponding to the load state of the engine 10.

  Next, in the flowchart of FIG. 2, among the processing steps executed by the ECU 38, for example, when the driver suddenly presses the accelerator pedal and the load on the engine 10 suddenly increases, such as during acceleration. The drive control process of the fuel pump 22 is shown. In the flowchart of FIG. 2, it is assumed that the rated voltage 12V of the battery 32 is applied to the DC motor 34 and fuel having a constant discharge flow rate is discharged from the fuel pump 22 toward the engine 10 side.

  The flow rate of fuel actually injected into the combustion chamber of the engine 10 by the fuel injection valve 16, that is, the required fuel flow rate of the engine 10 is detected by the discharge flow rate sensor 40, and the ECU 38 is detected by the discharge flow rate sensor 40. It is assumed that the required engine flow rate is provided so that it can be called as necessary.

  The fuel flow rate required by the engine 10 (engine required flow rate) is set based on, for example, an opening detection value (resistance value) of a throttle opening sensor 44 that accompanies a driver's depression of an accelerator pedal (not shown). Further, the required engine flow rate is not always constant, and varies depending on various conditions such as the engine speed, the atmospheric pressure, the engine temperature, and the operating state of the engine 10.

  Further, the fuel injection amount injected from the fuel injection valve 16 is detected by, for example, the engine rotational speed detected by the rotational speed sensor 42 and an air flow meter (not shown) provided in the intake passage 12. It may be calculated based on the air intake flow rate corresponding to the load state (or the air intake negative pressure of an intake manifold (not shown)). Further, the fuel injection amount may be obtained based on the rotational speed change rate of the engine 10. Further, the fuel injection amount may be obtained based on the valve opening or the rate of change of the valve opening (not shown) detected from the throttle opening sensor 44.

  First, the ECU 38 compares the engine required flow rate detected by the discharge flow rate sensor 40 with a preset rated flow rate of the fuel pump 22 (step S1). In this case, the rated flow rate of the fuel pump 22 refers to a reference flow rate set in advance based on a standard life when the fuel pump 22 is continuously operated with a constant voltage applied to the DC motor 34.

  The ECU 38 determines that the required engine flow rate detected by the discharge flow rate sensor 40 is larger than a preset rated flow rate of the fuel pump 22 and that the required engine flow rate exceeds the rated flow rate (rated flow rate <engine (Required flow rate) (Yes in step S1 → step S2), and then, it is determined whether or not the accumulated time of the boosted state stored in the nonvolatile memory (EEPROM) (not shown) has passed a predetermined time ( Step S2).

  The ECU 38 satisfies the required flow rate of the engine 10 when the required engine flow rate detected by the discharge flow rate sensor 40 is equal to or lower than a preset rated flow rate of the fuel pump 22 (rated flow rate ≧ engine required flow rate). Thus, it is determined that the fuel is being discharged from the fuel injection valve 16, and the fuel discharge flow rate of the fuel pump 22 is set to the normal use flow rate within the range of the rated flow rate (when No in step S1 → step S7). .

  When a fuel flow rate corresponding to a required flow rate exceeding the rated flow rate is discharged from the fuel pump 22, a non-illustrated non-volatile memory (storage means) (for example, a boosting time of the fuel pump 22 measured by a timer circuit not shown) Stored in an EEPROM or the like), and when the ignition switch (not shown) is turned on, the accumulated time data stored in the nonvolatile memory is called up, and the fuel pump 22 is driven in excess of the pump rated flow. Is set so as not to exceed, for example, about 10 percent of the standard life time of the fuel pump 22. When the accumulated time in the boosted state exceeds a predetermined time, a warning lamp 48 provided on a display unit (not shown) is turned on to alert the driver and set to a normal use flow rate equal to or lower than the rated flow rate (step S2). If YES, step S2a → step S7). This processing corresponds to the processing of “processing means for stopping the supply of fuel exceeding the rated flow rate”.

  When the ECU 38 determines that the engine required flow rate exceeds the rated flow rate (rated flow rate <engine required flow rate) and the accumulated time in the boosted state has not passed the predetermined time (No in step S2 → step S3), A converter control signal is derived to the fuel pump control unit 36 and the DC-DC converter 46 is energized (step S3), and the pump drive voltage is boosted to a predetermined voltage that is equal to or higher than the rated voltage (12V) of the battery 32 (step S4). ).

  The DC-DC converter 46 boosts the pump drive voltage to an applied voltage corresponding to the engine maximum required flow rate, so that the DC motor 46 is driven by a predetermined applied voltage exceeding the battery rated voltage (12 V), and the fuel pump. The fuel flow rate corresponding to the engine maximum required flow rate is discharged from 22.

  In a state where the pump drive voltage is boosted to a predetermined voltage equal to or higher than the rated voltage, the ECU 38 further compares the engine required flow rate detected by the discharge flow rate sensor 40 with a preset rated flow rate of the fuel pump 22; When it is determined that the engine required flow rate exceeds the rated flow rate (rated flow rate <engine required flow rate) (Yes in step S5), the boosted state of the pump drive voltage is further increased under the driving action of the DC-DC converter 46. Let it continue.

  On the other hand, when the ECU 38 determines that the engine required flow rate is equal to or lower than the preset rated flow rate of the fuel pump 22 (rated flow rate ≧ engine required flow rate) (No in step S5 → step S6), the ECU 38 determines the fuel pump control unit 36. The control signal is derived, the DC-DC converter 46 is deactivated (step S6), and the boosting state is stopped. Further, the ECU 38 sets the fuel discharge flow rate of the fuel pump 22 to a normal use flow rate equal to or lower than the rated flow rate (step S7).

Next, FIG. 3 shows a modification of the present embodiment based on the characteristic relationship between the pump drive voltage of the fuel pump 22 and the required engine flow rate. As shown in FIG. 3, the boosting by the DC-DC converter 46 is performed by raising the pump drive voltage until a preset engine maximum required flow rate is reached. This boosting state is shown in FIG. The voltage may be boosted stepwise as in the A state, or may be boosted linearly as in the B state.
Further, in the normal use state, the voltage is linearly boosted (see line LA) under the driving action of the DC-DC converter 46 within the rated voltage range of the battery 32, or the low mode, middle mode, high mode, etc. As described above, the voltage may be boosted in a substantially staircase pattern corresponding to each mode (see line LB), and further boosted in a plurality of staircase patterns (not shown) along the line LA.

  In the present embodiment, when the load on the engine 10 suddenly increases, the pump driving voltage is boosted to a predetermined voltage equal to or higher than the rated voltage (12 V) via the DC-DC converter 46, thereby fuel corresponding to the engine load. Can be suitably supplied to the engine 10. As a result, in this embodiment, the required fuel flow rate of the engine 10 can be satisfied by a simple mechanism, and the manufacturing cost can be reduced.

  Further, in the present embodiment, the fuel pump 22 for discharging the fuel to the fuel injection valve 16 is a fuel pump 22 whose flow characteristics are lowered by one rank with reference to a fuel pump that is assumed to be normally used. Thus, the fuel pump 22 itself can be reduced in size and weight, and the manufacturing cost can be further reduced.

  Furthermore, in the present embodiment, it becomes possible to use the fuel pump 22 that has been reduced in size and weight, thereby reducing the power consumption, the heat generation amount, the vibration of the fuel flow noise, etc. in the state of the normal use flow rate.・ An effect to suppress noise is obtained.

  The pump drive voltage control by the fuel pump control unit 36 is performed over the entire range of the required flow rate of the engine 10, thereby stabilizing the drive control for the DC motor 46 and stabilizing the fuel supply from the fuel pump 22 to the engine 10. It can be made.

Is a schematic block diagram of a fuel pump system GoSo location according to an embodiment of the present invention. It is a flowchart which shows the process of carrying out drive control of the fuel pump when the load with respect to an engine increases rapidly. It is the figure which showed the modification of this embodiment based on the characteristic relationship between the pump drive voltage of a fuel pump and an engine required flow rate.

Explanation of symbols

10 Engine 22 Fuel Pump 30 Fuel Pump Control Device 32 Battery (DC Power Supply)
34 DC motor (DC electric motor)
36 Fuel pump control unit (fuel pump control means)
40 Discharge flow sensor 42 Rotational speed sensor 44 Throttle opening sensor

Claims (2)

A fuel pump for sucking and discharging the fuel in the fuel tank;
A direct current electric motor attached to the fuel pump and driving the fuel pump;
A DC power source for supplying a driving current for driving the DC electric motor;
In a fuel pump control device that changes a flow rate of fuel supplied to an engine in response to an applied voltage applied to the DC electric motor,
The discharge flow rate of the fuel pump is set to a rated flow rate when the DC electric motor is driven at the rated voltage of the DC power source, and a normal use flow rate when driven at less than the rated voltage,
The DC power source includes voltage control means for boosting the applied voltage to a predetermined voltage equal to or higher than the rated voltage,
When the voltage control means determines that the required flow rate of fuel required by the engine exceeds the rated flow rate based on the engine load, the voltage control means boosts the applied voltage in a range up to a predetermined voltage equal to or higher than the rated voltage. Driving the DC electric motor with the boosted applied voltage to supply fuel to the engine at a discharge flow rate that exceeds the rated flow rate and is within the range up to the engine maximum required flow rate ,
When it is determined that the required flow rate is equal to or less than the rated flow rate after boosting the applied voltage, the boosting is stopped, and the discharge flow rate of the fuel pump is set to the normal use flow rate. . The fuel pump control device according to claim 1, wherein
Storage means for storing a time when the fuel pump is driven exceeding the rated flow rate;
Supply of fuel exceeding the rated flow rate when the total driving time reaches a preset time considering the standard life when the applied voltage applied to the DC electric motor is constant and continuously operated Processing means for stopping the vehicle and informing the driver of the fact,
The fuel pump control device further comprising:

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