Driving device of fuel injection device
阅读说明：本技术 燃料喷射装置的驱动装置 (Driving device of fuel injection device ) 是由 草壁亮 安部元幸 青野俊宏 冈本多加志 于 2015-04-22 设计创作，主要内容包括：本发明一方面抑制驱动装置的计算负荷和压力传感器所需的性能、另一方面检测各汽缸的燃料喷射装置的喷射量偏差并加以修正。本发明的燃料喷射装置的驱动装置是以如下方式进行控制：对进行燃料流路的开闭的多个燃料喷射装置各自的螺线管以设定好的通电时间流动电流而达到通电电流,由此驱动可动阀而喷射规定量的燃料；该燃料喷射装置的驱动装置的特征在于,根据来自安装于所述多个燃料喷射装置的上游侧的燃料管路上的压力传感器的压力检测值,对所述设定好的通电时间或通电电流进行修正。(The invention relates to a fuel injection device, which can suppress the calculation load of a driving device and the performance required by a pressure sensor, and can detect and correct the injection quantity deviation of the fuel injection device of each cylinder. The driving device of the fuel injection device of the invention is controlled in the following way: supplying a current to solenoids of a plurality of fuel injection devices that open and close fuel flow paths for a set energization time to reach an energization current, thereby driving a movable valve to inject a predetermined amount of fuel; the drive device for a fuel injection device is characterized in that the set energization time or energization current is corrected based on a pressure detection value from a pressure sensor attached to a fuel line on the upstream side of the plurality of fuel injection devices.)
1. A drive device for a fuel injection device, which is controlled in the following manner: a drive device for a fuel injection device, which drives a movable valve to inject a predetermined amount of fuel by supplying current to solenoids of a plurality of fuel injection devices that open and close fuel flow paths for a set energization time to reach an energization current,
correcting the set energization time or energization current based on a difference between a pressure detection value from a pressure sensor attached to one of the fuel lines upstream of the plurality of fuel injection devices or the plurality of fuel injection devices at a predetermined timing from when a valve opening signal for driving the movable valve is turned on and the pressure detection value before the valve opening signal is turned on,
the predetermined time is set using sensor information detected by the drive device.
2. The drive device of a fuel injection device according to claim 1,
the sensor information detected by the drive device is information of a crank angle detected by a crank angle sensor.
Technical Field
The present invention relates to a drive device for driving a fuel injection device of an internal combustion engine.
Background
In recent years, due to the enhancement of emission control of carbon dioxide and the concern about depletion of fossil fuels, reduction of fuel consumption (fuel consumption rate) of internal combustion engines has been sought. Therefore, efforts have been made to reduce various losses of the internal combustion engine to reduce fuel consumption. Generally, when the loss is reduced, the output required for the operation of the internal combustion engine can be reduced, and therefore the minimum output of the internal combustion engine can be reduced. In such an internal combustion engine, it is necessary to control to supply a smaller amount of fuel corresponding to the lowest output.
In recent years, attention has been paid to a small engine that is reduced in exhaust gas amount, is reduced in size, and is output by a supercharger. In a miniaturized engine, by reducing the amount of exhaust gas, pumping loss and friction can be reduced, and therefore fuel consumption can be reduced. On the other hand, fuel efficiency can be reduced by obtaining a sufficient output by using a supercharger and suppressing a decrease in the compression ratio associated with supercharging by the intake air cooling effect by direct injection in the cylinder. In particular, in the fuel injection device for the downsized engine, it is necessary to be able to inject fuel over a wide range from a minimum injection amount corresponding to a lowest output at a low exhaust gas amount to a maximum injection amount corresponding to a highest output obtained by supercharging, and there is a demand for an increase in a control range of the injection amount.
Further, with the intensification of the emission control, the engine is required to have a fuel injection device that can control the injection amount of a minute amount by requiring the total amount of unburned Particles (PM) and the Number thereof, that is, the Number of unburned Particles (PN) during the suppression mode traveling. As a method for suppressing the generation of unburned particles, it is effective to divide the spray in the 1-combustion stroke into a plurality of times and perform injection (hereinafter, referred to as split injection). Since the adhesion of the fuel to the piston and the cylinder wall surface can be suppressed by the split injection, the injected fuel is easily vaporized, and the total amount of unburned particles and the number thereof, that is, the number of unburned particles can be suppressed. In an engine that performs split injection, the fuel that has been injected 1 time in the past must be split into multiple injections, so the fuel injection device must be able to control an injection amount that is slightly smaller than in the past.
Generally, the injection quantity of the fuel injection device is controlled by the pulse width of an injection pulse output from an Engine Control Unit (ECU). When the injection pulse width is lengthened, the injection amount is increased, and when the injection pulse width is shortened, the injection amount is decreased, and this relationship is substantially linear. However, if the injection pulse width is shortened, the movable element and the fixed core do not collide with each other, that is, the valve element does not reach an intermediate opening degree region of the maximum opening degree. In the region of the intermediate opening degree, even if the same injection pulse is supplied to the fuel injection device of each cylinder, the displacement amount of the valve element of the fuel injection device greatly varies due to individual variations caused by the influence of dimensional tolerances, aged deterioration, or the like of the fuel injection device, and thus individual variations in the injection amount occur. Even when the displacement amount of the valve element is the same, individual variations in the injection amount occur due to the influence of dimensional tolerances such as the diameter of the injection hole that injects the fuel. Since the required injection amount is small in the region of the intermediate opening degree, the influence of individual variation in the injection amount on the homogeneity degree of the mixture gas becomes more significant, and it is difficult to use the region of the intermediate opening degree from the viewpoint of stability of combustion.
In order to reduce the minimum injection amount significantly, it is required to control the injection amount accurately by suppressing the injection amount deviation in a region where the injection pulse is small and the valve element does not reach the intermediate opening degree of the maximum opening degree.
To reduce the deviation of the injection amount at the intermediate opening degree, the following technique is required: the variation in the injection amount due to the dimensional tolerance of the fuel injection device, such as the individual difference in the time from the stop of the injection pulse until the movable element reaches the valve-closing position, can be detected for the fuel injection device of each cylinder, and the injection amount can be corrected for each individual. As a method of detecting an operation time of a valve element of a fuel injection device, which is a main factor of a variation in an injection amount, there is a method disclosed in patent document 1. Patent document 1 discloses the following method: the valve closing completion timing of the valve body is detected by comparing the induced electromotive voltage generated by the voltage of the coil with a reference voltage curve, and the valve closing time of the injection valve is determined based on the detection information.
Further, there is a case where deposits adhere to the injection hole from which the fuel is injected due to the influence of dimensional tolerance of the diameter of the injection hole of the fuel injection device, aged deterioration, or the like, and the injection amount varies. As the generation factor of the deposit, there are a case where Soot (Soot) generated by combustion enters the injection hole and a case where fuel is accumulated around the injection hole to become a deposit. In this case, even when the time-series distribution of the valve elements of the fuel injection device of each cylinder, that is, the closing completion timing is the same, the injection amount deviation occurs. For example, the following methods are disclosed: as described in
Disclosure of Invention
Problems to be solved by the invention
In the fuel injection device, the valve element is opened/closed by supplying and stopping the drive current to the solenoid (coil), but there is a time delay from the start of the supply of the drive current until the valve element reaches the maximum opening degree, and if the injection amount is controlled under the condition that the valve element performs the valve closing operation after reaching the maximum opening degree, there is a limitation in the minimum injection amount that can be controlled. Therefore, to control a small injection amount, it is necessary to accurately control the injection amount under the condition that the valve element does not reach the intermediate opening degree of the maximum opening degree. However, in the state of the intermediate opening degree, the movement of the valve element is an unreliable operation that is not limited by the physical stopper, and therefore, the injection period during which the valve element is in the open state, which is obtained by subtracting the time of the valve element opening start timing from the time of the valve element closing timing from the time of the injection pulse for driving the fuel injection device being ON, has a variation in the fuel injection device per cylinder.
The flow rate of injection from the fuel injection device is determined by the total cross-sectional area of the injection holes and the integrated area of the valve element displacement during the injection period when the valve element is open. Therefore, in order to reduce the variation in the injection amount of the fuel injection device for each cylinder, it is necessary to make the injection period during which the valve element is displaced coincide with the fuel injection device for each cylinder, and further to correct the variation in the injection amount due to the individual variation in the total cross-sectional area of the injection hole or the durability deterioration.
As a method of correcting the deviation of the injection amount due to the individual difference in the diameter of the injection hole, the following methods are disclosed: in the fuel injection state detection device described in
The purpose of the present invention is to suppress the computational load of a drive device and the performance required of a pressure sensor, and to detect and correct the variation in the injection amount of a fuel injection device for each cylinder.
Means for solving the problems
In order to solve the above problem, the present invention is a driving device of a fuel injection device, which performs control in the following manner: the drive device for a fuel injection device, which drives a movable valve to inject a predetermined amount of fuel by supplying current to solenoids of a plurality of fuel injection devices that open and close fuel flow paths for a set energization time to reach an energization current, is characterized in that the set energization time or energization current is corrected based on a pressure detection value from a pressure sensor attached to a fuel line on an upstream side of the plurality of fuel injection devices or one of the plurality of fuel injection devices.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to provide a drive device capable of suppressing the load on the drive device and estimating the variation in the injection amount of the fuel injection device for each cylinder, thereby reducing the controllable minimum injection amount.
The constitution, operation and effect of the present invention other than those described above will be described in detail in the following examples.
Drawings
Fig. 1 is a schematic diagram of a case where the fuel injection device, the pressure sensor, the drive device, and the ECU (engine control unit) described in embodiments 1 to 4 are mounted on an in-cylinder direct injection engine.
Fig. 2 is a longitudinal sectional view of a fuel injection device, and the configuration of a drive circuit and an Engine Control Unit (ECU) connected to the fuel injection device according to first to fourth embodiments of the present invention.
Fig. 3 is a cross-sectional enlarged view showing a structure of a driving portion of the fuel injection device according to the first to fourth embodiments of the present invention.
Fig. 4 is a diagram showing the relationship between the normal injection pulse for driving the fuel injection device, the timing of the drive voltage and the drive current supplied to the fuel injection device, and the valve element displacement amount and time.
Fig. 5 is a diagram showing a relationship between the injection pulse width Ti output from the ECU and the fuel injection amount in fig. 4.
Fig. 6 is a graph showing a relationship between an injection pulse width Ti and a fuel injection amount of a general fuel injection device in which individual variations in injection amount characteristics occur.
Fig. 7 is a diagram showing valve behavior at
Fig. 8 is a diagram showing details of a drive device of a fuel injection device and an ECU (engine control unit) in the first to fourth embodiments of the present invention.
Fig. 9 is a graph showing the relationship between the displacement amount of the valve element and the pressure detected by the pressure sensor and time for 3 individual fuel injection devices having different valve element trajectories under the condition of the same injection pulse width at the intermediate opening degree in example 1.
Fig. 10 is a flowchart showing a correction method of the injection amount provided in the injection amount deviation correction unit in
Fig. 11 is a diagram showing the relationship between injection pulse, valve element displacement amount, pressure and time when the valve element opening start timing is made to coincide for each fuel injection device in
Fig. 12 is a diagram showing the relationship between the inter-terminal voltage, the drive current, the current 1-order differential value, the current 2-order differential value, and the displacement amount of the
Fig. 13 is a graph showing the relationship between the drive current, the valve element displacement amount, the inter-terminal voltage, and the 2 nd order differential value of the inter-terminal voltage of 3 fuel injection devices whose valve element behavior fluctuates due to the influence of the fluctuation in the dimensional tolerance, and time in the 2 nd and 3 rd embodiments of the present invention.
Fig. 14 is a table showing the correspondence relationship between the displacement between the movable element and the fixed core after the stop of the injection pulse, the magnetic flux passing through the movable element, and the voltage, which is the detection principle of the valve closing completion timing in
Fig. 15 is a diagram showing the relationship between the injection pulse, the valve element displacement amount, the pressure, and the time when the valve opening start timings of the respective bodies are matched by using the injection pulse Ti in
Fig. 16 is a diagram showing the relationship between injection pulse, drive current, valve element displacement amount, pressure detected by the pressure sensor, and time when the injection periods of the valve elements are made to coincide among the individual fuel injection devices in embodiment 3 of the present invention.
Fig. 17 is a diagram showing a relationship between an injection period and an injection amount of each body of the fuel injection device according to embodiment 3 of the present invention.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
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