JPS646332B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides fuel injection in one or more cylinders calculated according to engine operating conditions, such as load, rotation speed, outside temperature, engine water temperature, etc. is stopped in a timely manner, and maximum efficiency combustion is achieved in the remaining operating cylinders.
Alternatively, the present invention relates to a fuel injection suspension control device that controls engine output by performing combustion that generates less NOX and the like.

(Prior art) Generally, in order to control the engine output of an internal combustion engine, for example, in a multi-cylinder diesel engine, the amount of fuel injected into each cylinder is increased or decreased using an injection pump. Depends on fuel quantity. Furthermore, the exhaust state also depends on the amount of fuel injected for each cylinder. These combustion efficiency and exhaust conditions also greatly depend on many other operating conditions such as rotational speed, outside temperature, and outside pressure. Therefore, technology is being developed to use electronic technology to control diesel engines and gasoline engines in accordance with the various conditions of the engine.

(Problems with the prior art) However, in many applications such as vehicles, engine output must be varied over a wide range from 0 to 100%, so if all cylinders are operated, for example, the maximum efficiency of the engine You cannot drive only.
To solve this problem, conventional methods have been used, for example, to stop the fuel supply to three of the six cylinders during low loads. It has been difficult to constantly improve the maximum combustion efficiency or exhaust components in a fuel injection cylinder even in the face of ever-changing conditions. In addition, proposals have been made for lowering the cylinder pressure using a decompressor or for variable cylinder capacity engines, but these proposals use conventional mechanical fuel injection devices and mechanically reduce the number of active cylinders. However, this method has disadvantages such as the fact that it is very complicated and it takes time to increase or decrease the number of active cylinders, making it impossible to operate it frequently.

In addition, as a way to improve these techniques, as disclosed in Japanese Patent Application Laid-open No. 53-27734 and Japanese Patent Application Laid-Open No. 54-120314, the number of deactivated cylinders is electrically controlled according to the operating condition. , techniques are known that are intended to achieve high combustion efficiency in the active cylinder.

However, in all of these conventional technologies, one control cycle of the stop control is determined depending on the number of cylinders that the engine has, so in a four-cylinder engine, for example, if the required injection amount increases and the If the fuel cannot be covered by three injections, it is necessary to cancel the pause control and switch to all-cylinder injection.In the end, highly accurate pause control is achieved over a wide range of operating conditions and injection is performed at maximum efficiency. It was impossible to carry out. Such drawbacks were particularly noticeable in engines with a small number of cylinders.

The present invention eliminates the above-mentioned drawbacks, provides a fuel injection pause control device with a greater degree of freedom, and makes it possible to always utilize the active cylinders with the best efficiency during fuel injection pause control, thereby improving fuel efficiency and cleanliness. The purpose is to realize safe driving.

(Means for Solving the Problems) The configuration of the present invention is as shown in the block diagram shown in FIG. 8. When described with reference to FIG. A fuel injection suspension control device that sets a predetermined number of injections when injection is performed as one control cycle and electrically controls the actual number of injections performed in this control cycle, and calculates the amount of fuel to be supplied to the engine. The fuel amount calculation means 50, the control period setting means 60 which sets one control period according to the operating state by setting the predetermined number of injections according to the operating state of the engine, and the control period setting means 60. an injection execution number calculation means 70 that calculates a minimum number of injection executions in one control cycle from the predetermined number of injections and the fuel amount calculated by the fuel amount calculation means 50; It is characterized by comprising a combustion injection means 80 that operates during one control period to perform fuel injection.

(Operation) According to the present invention, one control cycle is determined from the predetermined number of injections set as described above and the amount of fuel to be supplied to the engine, using the operating state as a parameter,
Furthermore, since the number of injection executions in one control cycle is determined to the minimum value, combustion can be precisely controlled with an injected fuel amount with high combustion efficiency over a wide range of operating conditions, regardless of the number of cylinders in the engine. will be held.

(Example) Fig. 1 shows the configuration for one cylinder of an electronically controlled hydraulically driven diesel injection device that can be used in the present invention. It is shown.

In FIG. 1, 1 is a fuel injection nozzle, 2 is a piston, 3 is a spool valve, 4 is a solenoid valve, 5 is a fuel tank, 6 is a filter, 7 is a hydraulic pump, 8 is an accumulator, 9 is a safety valve, 10 is a solenoid valve, 1
00 is a computer. In the figure, a computer 100, a natural material tank 5, a filter 6, a hydraulic pump 7, an accumulator 8, and a safety valve 9 are common to each cylinder of a diesel engine, but a fuel injection nozzle 1, a piston 2, a spool valve 3, Solenoid valve 4
and 10 are provided for each cylinder. computer 1
The electromagnetic valves 10 and 4 are actuated by the electric signal from 00, and the spool valve 3 is controlled to control the hydraulic pressure in the hydraulic chamber 2a that is applied to the piston 2. The piston 2 increases the pressure of fuel oil supplied from the fuel tank 5 through the filter 6, hydraulic pump 7, safety valve 9, accumulator 8, and spool valve 3, and applies it to the injection nozzle 1 for injection. That is, the solenoid valve 10 is turned on, the valve body of the spool valve 3 is moved to the right in the figure, fuel is sent from the hydraulic path 3a to the hydraulic chamber 2a, the piston 2 is operated downward, and the pressure inside the pressurizing chamber 2b is Inject fuel from the injection nozzle. In addition, injection can be completed by turning on the solenoid valve 4, releasing the pressure in the hydraulic chamber 2a to the fuel tank 5, and raising the piston 2. The illustrated example is the simplest example in which fuel is also used as hydraulic fluid for a hydraulic system, and in this case, for example, in the case of a six-cylinder engine, one accumulator 8 may be provided for every two cylinders. It goes without saying that the hydraulic system may be configured as a separate system independent of the fuel system. Therefore, when a multi-cylinder engine is configured using this configuration, the control circuit of the computer 100 controls the solenoid valve 1.
By turning on/off signals 0 and 4, it is possible to independently operate or stop the fuel injection valves of each cylinder. Furthermore, with the recent development of microcomputers, it has become possible to perform various types of arithmetic processing at high speed, so when the above-mentioned configuration is combined with a microcomputer-based control circuit, not only each cylinder but also the amount and timing of each injection itself can be controlled electromagnetically. The on/off timing of the valves 10 and 4 can be controlled independently, so to speak.

FIG. 2 shows an example of the configuration of a six-cylinder engine to which the present invention is applied. The engine 300 includes an injection nozzle 1, a piston 2, a spool valve 3, a solenoid valve 4, as shown in FIG.
The engine 300 is equipped with six fuel injection devices 200 including 10, and the engine 300 is equipped with sensors for crank angle, water temperature, etc. and is connected to the computer 100. The computer 100 is mainly composed of a microcomputer and a solenoid valve drive circuit, and detects the state of the engine by detecting intake temperature, intake pressure, etc. using various sensors of the engine, and performs fuel injection suspension control as shown below according to a program. Perform calculations and control. FIG. 3 is an example of a control pattern for the six-cylinder engine shown in FIG. 2. In actual engine control, when operating with cylinder deactivation as described above, for example, it is better to operate the engine with all six cylinders due to constraints from factors such as engine vibration and engine noise. There is an operating area. This is determined by the configuration of the engine, its usage conditions, etc.

FIG. 3 shows an example of a region and a control pattern in which fuel injection suspension control is performed in the six-cylinder engine shown in FIG. 2. In actual engine control, if a cylinder with no injection is provided, uneven rotation may occur, causing problems such as vibration and engine noise. In region a, fuel injection suspension control is not performed. That is, in this region a, normal operation is performed using all six cylinders. This area a is determined by the configuration of the engine, its operating conditions, and the like.

The present invention aims to achieve maximum combustion efficiency in each cylinder in any operating state outside of region a, that is, to perform each injection in the maximum efficiency state possible. Therefore, the total number of cylinders in operation (the number of injections performed) is reduced to the minimum during partial load, and the amount of fuel in each cylinder (the amount of injection per injection) is maintained at approximately the maximum efficiency point. Therefore, specifically, one control cycle of the pause control is determined based on a predetermined number of injections that corresponds to when all cylinder fuel injection is continued without stopping injection, and the control cycle is determined based on the predetermined number of injections, and the control cycle is determined based on the predetermined number of injections. Based on the predetermined number of injections and the total amount of fuel to be supplied to the engine calculated in advance, the number of injections performed in one control cycle is minimized to inject fuel into the cylinder at maximum efficiency. is operating.

In region b of Fig. 3, one control period (corresponding to 2 crankshaft rotations in the 6-cylinder 4-stroke engine of this embodiment) is set as the number of injections N = 6, which corresponds to when all cylinder injection is considered. be done.

FIG. 4 shows the relationship between the number of injection executions (upper row) in region b of FIG. 3 and the amount of fuel injected per time for each operating cylinder (lower row). From Figure 4,
It can be seen that in region b, the amount of fuel per operation for each activated cylinder is increased to nearly 100% of the maximum amount, increasing combustion efficiency.

In addition, regions c and d in Fig. 3 are the high speed rotation range of the engine, region c is 12 fuel injections (4 revolutions of the crankshaft) when all cylinders are injected, and region d is 24 fuel injections (8 revolutions of the crankshaft). ) is one control period, and the total number of operating cylinders corresponding to Fig. 4 is 0 to 12 and 0 to 24.
control.

Here, FIG. 5 shows the relationship between the number of injection executions and the fuel in the activated cylinders per injection in region c of FIG. 3.

Further, in the lower part of FIGS. 4 and 5, the dashed line shows the fuel in the activated cylinders per injection when normal injection is performed without setting any cylinders to be deactivated.

In the example shown in Fig. 3 above, the number of injections N when all cylinders are injected is an integral multiple of the number of engine cylinders (N
= 6, 12, 24), and of course it is also possible to set N = 20 as one control cycle of the fuel injection suspension control, regardless of the number of engine cylinders.

Also, the value of N is set smaller for lower load operation, but this is because the time interval between injections becomes longer in low load operation due to the lower rotation speed, so if the value of N is set too large, This is because the injection interval becomes very wide especially in the low fuel range, resulting in large rotational irregularities.

Also, of course, in areas other than area a in Fig. 3, pause control is prohibited when the load is relatively low (i.e., a
All-cylinder operation may be performed as in the area).

Further, in general, for example, in a diesel engine, when looking at the relationship between the engine load and the amount of NO _x generated, there is a relationship as shown in FIG. 7. Therefore, when the engine is at 6/8 load, it is better to perform combustion close to 8/8 (100%) in each cylinder, but according to this example, as is clear from Fig. 5, It can be seen that it is possible to significantly increase the amount of fuel per cylinder activation to nearly 100%, thereby improving the exhaust gas composition.

FIG. 6 is a flowchart showing each control step for performing the control shown in FIGS. 3 to 5 by a microcomputer. That is, first, in steps 1, 2, and 3, engine conditions are determined by reading each sensor, and the amount of fuel is calculated from the required engine output according to a predetermined algorithm. Next, in step 4, the engine speed,
Based on the engine load such as the amount of fuel, the control range of the engine is determined according to the pattern shown in FIG. Based on this result, in Step 5, the total number of active cylinders (the number of dormant cylinders is also determined) and the fuel amount for each activated cylinder are determined from the number of deactivated cylinders and fuel amount patterns shown in Figures 4 and 5. calculate. Furthermore, in step 6, it is determined which cylinder to deactivate (that is, which cylinder to operate) according to a previously programmed deactivated cylinder distribution method based on the engine speed and the number of deactivated cylinders. This deactivated cylinder distribution method is determined in accordance with the engine to which the present invention is applied so as to minimize engine vibration and to prevent load concentration on a particular cylinder.

In the control pattern shown in FIG. 3 of this example, all cylinders are operated in the low speed region, but in the idling region, it is also possible to operate with three out of six cylinders within a range where engine vibration is allowed.

In the above control, the engine output is changed continuously but in steps as shown in Figs. It is also possible to change the engine average output almost smoothly by increasing the value of N and increasing the control cycle to fix the value to , and by controlling the ratio of activated cylinders to deactivated cylinders more precisely.

Further, as shown in FIG. 2, a variable discharge type hydraulic pump 7 is used, and this is connected to the computer 100
By controlling the discharge amount according to the engine speed and the number of idle cylinders by controlling the electric signal from the
Control device losses can be reduced.

In the embodiments described above, fuel injection is only stopped for the idle cylinders, but depending on the engine, a decompressor may be installed to further reduce the cylinder pressure of the idle cylinders.

(Effects of the Invention) As described above, according to the present invention, one control period unit of the fuel injection pause control is set as the predetermined number of injections when all cylinders are injected, and first the predetermined number of injections is set to One control cycle is determined by setting according to the operating state of the engine, and further, from this predetermined number of injections and the amount of fuel to be supplied to the engine, the number of injection executions in one control cycle set according to the operating state is determined to be the minimum. Since the value has been determined to be , it is possible to precisely control combustion at an injected fuel amount with high combustion efficiency that always follows the operating condition regardless of the number of cylinders in the engine. Extremely excellent control of fuel efficiency and exhaust gas conditions can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of one cylinder of an electronically controlled hydraulically driven diesel injection device, Fig. 2 is a configuration diagram of a 6-cylinder engine to which the present invention is applied, and Fig. 3 is a 6-cylinder engine shown in Fig. 2. FIG. 4 is a diagram showing an example of a region and a control pattern in which fuel injection suspension control is performed,
Figure 5 is a diagram showing the relationship between the number of injection executions in region b in Figure 3 and the amount of fuel injected per time for each operating cylinder. FIG. 6 is a flowchart showing each control step performed by the control microcomputer shown in FIGS. 3 to 5. FIG. FIG. 8, which is a diagram showing the relationship between engine load and NO _x generation amount, is a block diagram showing the configuration of the present invention. 1... Fuel injection nozzle, 2... Piston, 3...
... Spool valve, 4, 10 ... Solenoid valve, 5 ... Fuel tank, 7 ... Hydraulic pump, 50 ... Fuel amount calculation means, 60 ... Control period determination means, 70 ... Injection execution number calculation means, 80 ...Fuel injection means, 10
0...computer, 200...fuel injection device,
300...Institution.

Claims (1)

[Claims] 1. A fuel injection pause in which a predetermined number of injections when fuel injection is performed in all cylinders without stopping injection is set as one control cycle, and the actual number of injections executed in this control cycle is electrically controlled. A control device, comprising: a fuel amount calculation means for calculating the amount of fuel to be supplied to the engine; and a control for setting one control period according to the operating state by setting the predetermined number of injections according to the operating state of the engine. a cycle setting means; and an injection execution number for calculating a minimum number of injection executions in one control cycle from the predetermined number of injections set by the control cycle setting means and the fuel amount calculated by the fuel amount calculation means. A fuel injection suspension control device comprising: a calculation means; and a fuel injection means that operates during the one control period to perform fuel injection for the minimum number of injection execution times.