JP2007016648A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device performing accurate control of a fuel injection module. <P>SOLUTION: This fuel injection device is provided with a fuel injection module 8 sucking, pressurizing fuel and injecting the same to an engine by reciprocating motion of a plunger induced by excitation of a coil, and a control unit 1 providing drive signal to the coil of the fuel injection module 8 based on an operation condition of the engine 100. A current detection circuit 14 detecting excitation current value of the coil and a storage means 15 storing correction data of detection of excitation current value of the coil of the current detection circuit 14 are provided. The control unit 1 corrects excitation current value detected by the current detection circuit 14 based on correction data of the storage means 15 and creates corrected current value, and calculates drive time of the coil based on the corrected current value and sends drive signal to the fuel injection module 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine fuel injection apparatus using a fuel injection module having a function of pressurizing fuel by a reciprocating motion of a plunger and a function of a fuel injection valve, and is for accurately controlling the fuel injection module. is there.

  In a conventional fuel injection device, an electronically controlled fuel injection device in which a control unit calculates a fuel supply amount according to an engine speed and a load and gives a drive signal to a fuel injection valve. A fuel injection module that sucks and pressurizes fuel to inject fuel has been proposed. The operation of the fuel injection module is to energize the coil with the drive signal given from the control unit, and the plunger pressurizes the fuel and injects at a predetermined fuel pressure, and then the plunger is pushed back by the spring and then injected. Aspirate the fuel.

  A fuel injection device using a fuel injection module has fewer components than a fuel injection device that pressurizes and regulates fuel with a fuel pump and regulator and injects pressurized fuel with an injector. This is advantageous in that the average power consumption is small because the power is supplied to the vehicle, and is particularly suitable for small two-wheeled vehicles with low generator and battery capabilities. However, there is a problem that the injection amount fluctuates due to the temperature dependence of the coil resistance value used in the fuel injection module. The energization current value is detected, and the drive time of the fuel injection module is corrected (see, for example, Patent Document 1).

JP 2003-113732 A

  The current detection means of the fuel injection module of the conventional fuel injection device generally detects the voltage at both ends by passing a current through a shunt resistor provided in the control unit. Is not suitable for the driving time. For example, according to the test of the present inventor, in the idling state where the ratio of the correction amount of the drive time by the detected current is large with respect to the time during which the fuel is actually injected, if the energization current value deviates by 1%, the fuel injection amount Was found to change by 3%. Also, the current detection accuracy of the current detection circuit in the control unit is limited to about 3% accuracy even when high-precision automotive parts are used. In this case, the fuel injection amount changes by 9%. There is a problem that the desired fuel injection accuracy cannot be obtained. In addition, although the influence is less than the above, there is a problem that the fuel injection amount varies depending on the temperature of the control unit because the energization current value varies depending on the temperature characteristics of the parts constituting the current detection circuit.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel injection device that performs accurate control of a fuel injection module.

  The present invention relates to a fuel injection module that sucks and pressurizes fuel by a reciprocating movement of a plunger generated by energizing a coil and injects the fuel into an engine, and a control unit that supplies a drive signal to the coil of the fuel injection module based on an operating state of the engine. And a storage unit for storing correction data for detecting the coil energization current value of the current detection unit. The control unit includes a current detection unit. A correction current value is generated by correcting the energization current value detected at the storage means based on the correction data of the storage means, and the drive time of the coil is calculated based on the correction current value and a drive signal is transmitted to the fuel injection module It is.

  The fuel injection device according to the present invention includes a fuel injection module that sucks and pressurizes fuel by a reciprocating motion of a plunger generated by energizing the coil and injects the fuel into the engine, and a drive signal to the coil of the fuel injection module based on the operating state of the engine. And a control unit comprising: a current detection unit that detects a current value of the coil; and a storage unit that stores correction data in the detection of the current value of the coil of the current detection unit. Corrects the energization current value detected by the current detection means based on the correction data of the storage means to create a correction current value, calculates the drive time of the coil based on the correction current value, and outputs a drive signal to the fuel injection module Therefore, the fuel injection module is accurately controlled by correcting the energization current value. Door can be.

Embodiment 1 FIG.
Embodiments of the present invention will be described below. 1 is a diagram showing the configuration of a fuel injection device according to Embodiment 1 of the present invention attached to an engine, FIG. 2 is a block diagram showing the configuration of a control unit of the fuel injection device shown in FIG. 3 is a waveform diagram showing the relationship between the drive signal of the fuel injection module and the energization current value of the coil in the fuel injection module. In the figure, a control unit 1 measures an intake air temperature sensor 2 that measures the temperature of intake air of the engine 100, a throttle position sensor 4 that measures the opening of the throttle valve 3, and an intake air pressure downstream of the throttle valve 3. The engine 100 is connected to various sensors such as an intake pressure sensor 5 and an engine temperature sensor 6 that measures the wall surface temperature of the engine 100. Based on detection values from the various sensors, an appropriate fuel injection timing and fuel injection amount of the engine 100 are determined. Calculate and output a drive signal to the fuel injection module 8.

  An appropriate ignition signal is output to the ignition coil 9 from the detection values of various sensors. The fuel injection module 8 moves the plunger with an electromagnetic force generated by energizing the internal coil, pressurizes the supplied fuel from the fuel tank 10 via the feed pipe 11 and the fuel filter 12, and supplies a predetermined pressure. And injected into the engine 100. When energization of the coil of the fuel injection module 8 is stopped, the plunger is returned to the original position by the return spring, and at that time, the fuel to be injected next is sucked. Excess fuel and vapor contained in the fuel are returned to the fuel tank 10 by the return pipe 13.

  FIG. 2 shows a state in which the fuel injection module 8 is connected to the control unit 1, and other input / outputs connected to the control unit 1 are omitted. The control unit 1 includes a drive signal output circuit for a fuel injection module 8 (not shown), a current detection circuit 14 as a current detection means for detecting a current flowing through a coil of the fuel injection module 8, and a flash memory. A microcomputer 16 incorporating a storage means 15 is provided. The storage unit 15 stores a program for performing fuel injection control of the engine 100. In addition to this, in the first embodiment, correction data obtained by applying a highly accurate current in the production line during the manufacture of the control unit 1 and comparing it with the current value detected by the current detection circuit 14. (Correction value: Ki) is stored.

Next, a method for creating a drive signal for the coil of the fuel injection module of the combustion injection apparatus according to Embodiment 1 configured as described above will be described. First, the current detection means 14 detects the energization current value Id after the elapse of Td time since the energization of the coil of the fuel injection module 8 is started. Next, the microcomputer 16 reads a correction value Ki as correction data from the storage means 15. The microcomputer 16 obtains the correction current value Id ′ by the following equation (1).
Id ′ = Ki × Id (1)

Next, the coil drive time of the fuel injection module 8 is corrected by the following equation (2) based on the correction current value Id ′.
Tdd = Tw (Id ′) + Kd (Id ′) × Tdb (2)
Tdd: corrected driving time Tw (Id ′): invalid injection time determined by Id ′ Kd (Id ′): correction value determined by Id ′ Tdb: basic injection time The control unit 1 uses this driving time as the fuel injection module 8 As a drive signal, the coil of the fuel injection module 8 is driven.

  According to the fuel injection device of the first embodiment configured as described above, correction data for correcting the energization current value is stored in the storage means, and the energization current value is corrected and corrected using this correction data. Since the current value is created, even when the current detection accuracy of the current detection circuit is low, a reliable correction is possible, and a fuel injection device with high fuel control accuracy can be obtained. Therefore, it is not necessary to use expensive high-precision parts in order to improve the detection accuracy of the current detection circuit. Furthermore, compared to the method of adjusting the current detection circuit in an analog manner, the adjustment process is simplified, and it is not necessary to attach an adjustment resistor or trim the trimmable resistor with a laser or the like, thereby reducing the processing cost. Can do. Further, since the flash memory is used as the storage means for storing the correction data, it is possible to use a part that has been conventionally used to store a program for performing fuel injection control. Can be done without increasing.

  In the first embodiment, the flash memory is used as the storage unit. However, the present invention is not limited to this. For example, as shown in FIG. 4, a nonvolatile memory provided outside the microcomputer 16 is used. The second storage means 17 comprising the EEPROM is provided, the flash memory as the storage means 15 stores a program for performing fuel injection control, and the correction data is stored in the EEPROM as the second storage means 17. You may make it do.

  In the fuel injection device configured as described above, the EEPROM serving as the second storage means 17 is provided in advance for storing the failure history of the system and the like, and is configured without increasing the component cost. be able to. Further, since the correction data is stored in the second storage means 17 provided separately from the storage means 15 for storing the fuel control program, the program for the fuel control is changed and the contents of the storage means 15 are rewritten. In this case, the correction data value does not change and can be used as it is. This enables efficient production when a plurality of types of control units are produced by writing a plurality of programs using the same control unit.

  Further, even when the fuel control program is frequently rewritten, such as calibration of fuel injection control at the time of vehicle development, it is possible to save the trouble of reading out the correction data and rewriting it, thereby improving the development efficiency. Further, when the correction data is stored in the EEPROM, a mask product (a custom product that cannot be rewritten) can be used in the microcomputer used in the fuel injection device. Since this mask microcomputer is cheaper than the microcomputer with built-in flash memory, a more inexpensive fuel injection device can be provided.

Embodiment 2. FIG.
FIG. 5 is a block diagram showing the configuration of the control unit of the fuel injection device showing Embodiment 2 of the present invention. In the figure, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Since the entire configuration of the fuel injection device other than the control unit is the same as that shown in FIG. 1 of the first embodiment, the description thereof will be omitted, and those portions will be described based on FIG. FIG. 5 shows a state in which the fuel injection module 8 is connected, and other input / outputs connected to the control unit 1 are omitted. A drive signal output circuit of a fuel injection module (not shown) in the control unit 1, storage means 15 in which a program for performing fuel injection control is stored, and a highly accurate current in the production line when the control unit 1 is manufactured. And correction data (correction value: Ki) obtained by comparing with the current value detected by the current detection circuit 14 and correction data (correction value: Kit (Tc)) based on temperature characteristics of the current detection circuit 14 described later. Is stored, a temperature sensor 18 for measuring the temperature of the current detection circuit 14, and the temperature of the current detection circuit 14 is calculated from the detected value detected by the temperature sensor 18. A temperature detection circuit 19 is provided.

  The temperature sensor 18 and the temperature detection circuit 19 constitute a temperature detection means 20 and a temperature for correcting the temperature characteristic of the current detection circuit 14 is detected. Therefore, since the temperature detection means 20 is provided to correct the temperature characteristics of the current detection circuit 14, it is desirable to arrange the temperature sensor 18 in the vicinity of the current detection circuit 14. In this example, correction data for the temperature characteristics of the current detection circuit 14 is obtained by measurement for each current detection circuit 14 and is stored in the second storage unit 17. When the same correction data is given uniformly, it may be stored in either the storage means 15 or the second storage means 17.

Next, a method of creating a drive signal for the coil of the fuel injection module of the combustion injection apparatus of the second embodiment configured as described above will be described. First, the current detection means 14 detects the energization current value Id after the elapse of Td time since the energization of the coil of the fuel injection module 8 is started. Next, the microcomputer 16 reads the correction data (correction value: Ki) from the second storage means 17 and further corrects the correction data (correction) for the temperature characteristics determined in advance based on the temperature detected by the temperature detection means 20. Value: Kit (Tc)) is read from the second storage means 17. Then, the microcomputer 16 obtains the corrected current value Id ′ of the current detection circuit 14 by the following equation (3).
Id ′ = Ki × Kit (Tc) × Id (3)
Tc: The temperature within the control unit detected by the temperature detecting means is corrected based on the correction current value Id ′ based on the correction current value Id ′ as in the first embodiment, based on the equation (2), The control unit 1 transmits this drive time as a drive signal to the fuel injection module 8 to drive the coil of the fuel injection module 8.

  According to the fuel injection device of the second embodiment configured as described above, in addition to the correction of the energization current value, the energization current value in the temperature characteristic is corrected based on the temperature detected by the temperature detection means. Therefore, even when the current detection circuit has temperature characteristics, a fuel injection device with high fuel control accuracy can be obtained.

  In each of the above embodiments, current detection means using a general shunt resistor is shown for current detection. However, the present invention is not limited to this, and current detection means using a current mirror may be used. Needless to say, similar effects can be obtained.

It is a figure which shows the structure of the fuel-injection apparatus of Embodiment 1 of this invention. It is a block diagram which shows the structure of the control unit of the fuel-injection apparatus shown in FIG. It is the wave form diagram which showed the relationship between the drive signal of a fuel injection module, and the energization electric current value of the coil in a fuel injection module. It is a block diagram which shows the structure of the other control unit of the fuel-injection apparatus shown in FIG. It is a block diagram which shows the structure of the control unit of the fuel-injection apparatus of Embodiment 2 of this invention.

Explanation of symbols

1 control unit, 8 fuel injection module, 14 current detection circuit,
15 storage means, 17 second storage means, 18 temperature sensor, 19 temperature detection circuit,
20 Temperature detection means.

Claims (3)

A fuel injection module that sucks and pressurizes fuel by a reciprocating motion of a plunger generated by energizing the coil and injects the fuel into the engine; and a control unit that supplies a drive signal to the coil of the fuel injection module based on the operating state of the engine. In the fuel injection device, the current detecting means for detecting the energization current value of the coil, and the storage means for storing correction data in the detection of the energization current value of the coil of the current detection means, The fuel injection module calculates the drive time of the coil based on the correction current value by correcting the energization current value detected by the current detection means based on the correction data of the storage means to create a correction current value. A fuel injection device that transmits a drive signal to the fuel injection device. A fuel injection module that sucks and pressurizes fuel by a reciprocating motion of a plunger generated by energizing the coil and injects the fuel into the engine; and a control unit that supplies a drive signal to the coil of the fuel injection module based on the operating state of the engine. In the fuel injection device, the current detection means for detecting the energization current value of the coil, the temperature detection means for detecting the temperature of the current detection means, the detection of the energization current value of the coil of the current detection means and the current Storage means for storing correction data on the temperature characteristics of the detection means, and the control unit corrects the energization current value detected by the current detection means based on the detected temperature of the temperature detection means and the correction data of the storage means. To create a corrected current value and drive the coil based on the corrected current value. Calculated fuel injection apparatus characterized by transmitting a drive signal to the fuel injection modules. 3. The fuel injection device according to claim 1, wherein the storage means is formed of a flash memory or a nonvolatile memory.

Images