JPH0256497B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fuel injection amount control method for each cylinder in an electronically controlled diesel engine, and is particularly suitable for use in an electronically controlled diesel engine for automobiles. Improvement of a method for controlling the fuel injection amount for each cylinder in an electronically controlled diesel engine, in which the fuel injection amount control actuator is controlled for each cylinder so that rotational fluctuations are uniform, and engine vibrations caused by variations in fuel injection amount between cylinders are suppressed. Regarding.

[Prior art]

In general, diesel engines have much larger vibrations than gasoline engines at engine speed, and the diesel engine, which is elastically supported by the engine mount mechanism, resonates due to the vibrations, which affects the comfort of the vehicle. In addition to worsening the problem, there were cases where it had a negative effect on equipment around the engine. For example, in the case of a four-stroke diesel engine, this is 1/2 of the engine revolution due to periodic variations in the fuel pumped to each cylinder in half the cycle of the diesel engine revolution.
It is mainly caused by the following low frequency vibrations. That is, in a diesel engine, when the fuel injection amount varies between cylinders, as shown in Fig. 1, the rotational fluctuation ΔNE is not equal for each explosion cylinder (every 180° CA (crank angle) for 4 cylinders).
A undulation S due to crank rotation occurs once every four explosions, and this causes discomfort to vehicle occupants. In the figure, TDC is top dead center. For this reason, it is possible to manufacture the engine body, fuel injection pump, and injection nozzle with extremely high precision to reduce the variation in fuel supplied to each cylinder, but this requires a large amount of production technology. In addition to being difficult, the fuel injection pump and the like become extremely expensive. On the other hand, it is possible to improve the engine mount mechanism to suppress engine vibrations, but this mount mechanism would be complicated and expensive, and it would not suppress the vibrations of the diesel engine itself.
The problem was that it could not be a fundamental countermeasure. In order to solve such problems, for example, as shown in FIG.
By the engine rotation sensor 22 attached to 2A
The NE raw waveform is obtained, and as shown in FIG. CA) For each rotation,
The time required to rotate 45°CA from ΔT to the previous 45°CA
Engine rotation speed NEi (i=1 to 4)
is calculated, and from the engine speed NEi, the rotational fluctuation DNEp (p=1
~4) is detected, and this and the average value of rotational fluctuations of all cylinders (hereinafter referred to as average rotational fluctuation) WNDLT (=
₄ 〓 ^P=1 DNEp/4), and if the rotational fluctuation of the relevant cylinder is smaller than the average rotational fluctuation WNDLT, it is assumed that the fuel injection amount of the relevant cylinder is small, and the difference (hereinafter , referred to as rotational fluctuation deviation)
According to DDNEp (p = 1 to 4), the fuel injection amount (hereinafter referred to as the correction amount each time) Δq that should be increased is learned, for example, as shown in Fig. 5, and reflected in the next fuel injection of the relevant cylinder. However, conversely, if the rotational fluctuation of the relevant cylinder is larger than the flat rotational fluctuation WNDLT,
It is conceivable to reduce the amount of fuel injected into the relevant cylinder. In this way, for example, as shown in FIG.
The fuel injection amount control actuator, such as the spill actuator for controlling spill rings in a distributed fuel injection pump, is controlled for each cylinder to increase or decrease the fuel injection amount for each cylinder until the rotational fluctuations of each cylinder are equalized. By doing so, it is possible to eliminate variations in fuel injection amount between cylinders, and therefore, engine vibration can be suppressed. In Fig. 6, ΔQp (p=1 to 4) is the cylinder correction amount which is the cumulative value of the correction amount Δq each time, and _K5 is neutral and the engine speed is 1000 to 1500 rpm.
Qfin is a correction coefficient that reduces the correction amount for each cylinder as the engine speed increases, in order to prevent hunting when the engine speed is
The injection amount, Vsp, calculated from NE, accelerator opening Accp, etc., is the output of a spill position sensor that detects the displacement of the spill actuator.

[Problems to be solved by the invention]

However, conventionally, the cylinder-specific correction amount ΔQp
Since the upper and lower limit guard values of 10 and 10 were kept constant regardless of temperature, there would be no problem when using fuel with low viscosity such as special No. 3 diesel oil, but if the fuel temperature is -10
When fuel with high viscosity such as No. 2 diesel oil is used in conditions below ℃, the followability of the spill ring becomes slow. There were cases where ΔQp was not reached. Then, since the cylinder-specific correction amount ΔQp is not sufficiently corrected, the rotational fluctuation deviation DDNEp
(=WNDLT-DNEp) is not reduced, and the next correction amount Δq corresponding to the rotational fluctuation deviation DDNEp is further integrated into the cylinder-specific correction amount ΔQp, resulting in a vicious cycle. The correction amount ΔQp exceeds the followable range of the spill ring and diverges to the upper and lower limits, and the correction amount ΔQp for each cylinder does not correspond to the amount of movement of the spill ring, making it impossible to correct the injection amount for each cylinder in time. This has had a problem in that it interferes with the correction of the next cylinder, and the cylinder-specific correction may not be performed properly. This applies not only when the temperature of the fuel is low, but also when the specific gravity of the fuel is high.

OBJECT OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional art. This can be done within a range that the actuator can follow, and therefore, due to the divergence of the correction amount, the correction of the previous cylinder will not interfere with the correction of the next cylinder, and the injection amount correction for each cylinder can be reliably performed. An object of the present invention is to provide a method for controlling fuel injection amount for each cylinder in an electronically controlled diesel engine that can minimize vibration levels.

[Structure of the invention]

The present invention detects and compares the rotational fluctuations of each explosion cylinder, controls the fuel injection amount control actuator for each cylinder so that the rotational fluctuations of each cylinder are uniform, and eliminates engine vibration caused by variations in the fuel injection amount between the cylinders. In the fuel injection amount control method for each cylinder of an electronically controlled diesel engine, which is designed to suppress A procedure for determining the cylinder-specific correction amount of the fuel injection amount control actuator according to the rotational fluctuation deviation, a procedure for detecting the specific gravity and temperature of the fuel, and a procedure for detecting the detected fuel specific gravity and the detected fuel temperature. A procedure for determining the upper and lower limit guard values of the cylinder-specific correction amount, which changes in accordance with the viscosity of the fuel, according to the value converted to the standard state using The above object is achieved by including a procedure for limiting the correction amount for each cylinder, and a procedure for controlling the fuel injection amount control actuator for each cylinder by the limited correction amount for each cylinder. Further, in an embodiment of the present invention, the absolute value of the upper and lower limit guard values is made smaller when the specific gravity is high, so that appropriate upper and lower limit guard values can be obtained according to the specific gravity and temperature of the fuel. This is what I did.

[Action of the invention]

In the present invention, the upper and lower limit guard values of the correction amount for each cylinder are changed in accordance with the specific gravity of the fuel and changes in this specific gravity due to temperature changes, and in accordance with the viscosity of the fuel. Regardless of the specific gravity of the fuel or changes in this specific gravity due to temperature changes, the fuel injection amount can always be kept within a range that can be followed by the fuel injection amount control actuator, thus preventing inter-cylinder correction interference due to divergence of the correction amount. be able to. In particular, since not only the temperature of the fuel but also the specific gravity is taken into consideration, the viscosity of the fuel can be estimated accurately, making it possible to control with even higher precision.

【Example】

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an electronically controlled diesel engine for automobiles will be described in detail with reference to the drawings, in which a method for controlling fuel injection amount by cylinder for an electronically controlled diesel engine according to the present invention is adopted. As shown in FIG. 10, this embodiment includes a drive shaft 14 that rotates in conjunction with the rotation of the crankshaft of a diesel engine 10, and a feed pump 16 (a feed pump 16) fixed to the drive shaft 14 for pumping fuel. (Figure 10 shows the state unfolded at 90 degrees), a fuel pressure regulating valve 18 for regulating the fuel supply pressure, and a fuel pressure regulating valve 18 for detecting the rotational state of the diesel engine 10 from the rotational displacement of the gear 20 fixed to the drive shaft 14. , an engine rotation sensor 22 consisting of, for example, an electromagnetic pickup, a roller ring 25 for driving the pump plunger 24 in cooperation with the face cam 23, and a timer piston 26 for controlling the rotational position of the roller ring 25 (Fig. 10). (indicates a 90° expanded state), a timing control valve 28 for controlling the fuel injection timing by controlling the position of the timer piston 26, and a timing control valve 28 for detecting the position of the timer piston 26, for example, a variable valve 28 for detecting the position of the timer piston 26. Timer position sensor 3 consisting of an inductance sensor
0, a spill ring 32 for controlling the timing of fuel release from the pump plunger 24; a spill actuator 3 for controlling the fuel injection amount by controlling the position of the spill ring 32;
4. Plunger 3 of the spill actuator 34
From the displacement of 4A, the position of the spill ring 32 Vsp
A spill position sensor 36 consisting of a variable inductance sensor, for example, to detect this, a fuel cut solenoid (hereinafter referred to as FCV) 38 to cut off fuel when the engine is stopped, and a delivery valve to prevent backflow or dripping of fuel. 42, an injection nozzle 44 for injecting the fuel discharged from the delivery valve 42 of the fuel injection pump 12 into the combustion chamber of the diesel engine 10, and an intake pipe 46. An intake pressure sensor 48 for detecting the pressure of the intake air taken in by the engine; an intake air temperature sensor 50 for also detecting the temperature of the intake air; A water temperature sensor 52 for detecting the depression angle of the accelerator pedal 54 operated by the driver (hereinafter referred to as accelerator opening degree) Accp, and an accelerator sensor 56 for detecting the fuel temperature THF in the fuel injection pump 12. A pump fuel temperature sensor 58 made of, for example, a thermistor or thermocouple, for detecting the fuel temperature THF ₀ in the fuel tank 60; A tank fuel temperature sensor 62 consisting of a thermocouple; and a hydrometer 64 of, for example, a bubble tube type, disposed in the fuel tank 60 and for detecting the specific gravity of the fuel.
and a remaining fuel gauge 66 disposed in the fuel tank 60 and consisting of, for example, a commonly used fuel gauge.
and the accelerator opening Accp detected from the output of the accelerator sensor 56 and the engine rotation sensor 22.
The control injection timing and control injection amount are determined from the engine rotational speed NE obtained from the output of the engine, the engine cooling water temperature detected from the output of the water temperature sensor 52, etc., and the control injection amount of fuel is injected from the fuel injection pump 12 at the control injection timing. An electronic control unit (hereinafter referred to as ECU) 68 controls the timing control valve 28, spill actuator 34, etc. so that the fuel is injected. As shown in detail in FIG. 11, the hydrometer 64 has a first bubble tube 64A with an insertion depth of X and a bellows formed in the middle to enable accurate measurement even when stopped on a slope. , a second bubble tube 64B with an insertion depth of Y and also having a bellows formed in the middle, and a check valve 64C for preventing backflow of air sent into the bubble tubes 64A and 64B. and 64D, and a differential pressure detector 64E made of, for example, a piezoelectric transducer, for detecting the differential pressure ΔP between the bubble tubes 64A and 64B.
Therefore, from the differential pressure ΔP detected by the differential pressure detector 64, the specific gravity ρ' of the fuel in the fuel tank 60 can be determined by using the following relationship. ρ'=ΔP/(X-Y)g (1) Here, g is gravitational acceleration. The ECU 68, as shown in detail in FIG.
A central processing unit (hereinafter referred to as CPU) 68A consisting of, for example, a microprocessor for performing various calculation processes, a clock 68B for generating various clock signals, and a clock 68B for temporarily storing calculation data etc. in the CPU 68A. Random access memory (hereinafter referred to as RAM) 68C,
Read-only memory (hereinafter referred to as ROM) 6 for storing control programs and various data, etc.
8D, the output of the water temperature sensor 52 inputted via the buffer 68E, the output of the intake temperature sensor 50 inputted via the buffer 68F, and the buffer 6
The output of the intake pressure sensor 48 is input via 8G, the output of the accelerator sensor 56 is input via buffer 68H, the output of pump fuel temperature sensor 58 is input via buffer 68I, and the output is input via buffer 68J. The sensor drive frequency of the tank fuel temperature sensor 62 output, the hydrometer 64 output input via the buffer 68K, the fuel level gauge 66 output input via the buffer 68L, and the sensor drive circuit 68M output. The output of the spill position sensor 36 is driven by a signal and input via the sensor signal detection circuit 68N.
Vsp, a multiplexer (hereinafter referred to as MPX) for sequentially taking in the output of the timer position sensor 30, etc., which is also driven by the sensor drive frequency signal output from the sensor drive circuit 68P and input via the sensor signal detection circuit 68Q. )68R and the MPX
Analog-to-digital converter (hereinafter referred to as A/
(referred to as a D converter) 68S and the A/D converter 68
an input/output port (hereinafter referred to as I/O port) 68T for taking in the output of S to the CPU 68A, and a waveform shaping circuit 68U for shaping the output of the engine rotation sensor 22 into a waveform and taking it directly into the CPU 68A. , a drive circuit 68V for driving the timing control valve 28 according to the calculation result of the average CPU 68A, a drive circuit 68W for driving the FCV 38 according to the calculation result of the CPU 68A, and a digital-to-analog converter. (hereinafter referred to as a D/A converter) 68X, the spill actuator 34
It is composed of a servo amplifier 68Y and a drive circuit 68Z for driving. The effects of the embodiment will be explained below. In this embodiment, first, as shown in FIG. 13, a 1-second routine that is periodically activated at predetermined time intervals, for example, every 1 second, is used to determine the specific gravity ρ' of the fuel and the fuel temperature in the tank THF _0. From this, calculate the specific gravity ρ of the fuel under standard conditions (for example, 15°C). Specifically, first, in step 110, the pump internal fuel temperature is determined from the output of the pump fuel temperature sensor 58.
Calculate THF. Next, the process proceeds to step 112, where the tank fuel temperature THF ₀ is calculated from the output of the tank fuel temperature sensor 62. Then step 114
Then, it is determined whether the idle state is stable. The reason why it is determined in step 114 whether or not the idle state is stable is because if the idle state is not stable, for example, when the vehicle is running, the hydrometer 64 may be tilted and the specific gravity may not be accurately detected. This is because there is. If the judgment result is positive, for example, during or immediately after starting (pseudo accelerator opening at starting AccpA≠
0), the accelerator opening Accp is 0%,
whether the shift position of the transmission is neutral or, in the case of an automatic transmission, the drive range;
And when all the conditions that the vehicle speed is zero are satisfied,
Proceeding to step 116, it is determined whether the remaining fuel amount detected from the output of the fuel remaining amount meter 66 is greater than or equal to the specified amount L. In this step 116, the fuel tank 6
The bubble tube type hydrometer 64 determines whether the remaining amount of fuel in the bubble tube 64A or 64B is not less than the specified amount L unless the tips of the bubble tubes 64A and 64B are covered with fuel. This is because accurate measurements cannot be made. If the determination result in step 116 is positive, that is,
When it is determined that it is possible to obtain an accurate specific gravity measurement value, the process proceeds to step 118, and from the output ΔP of the differential pressure detector 64E of the hydrometer 64, the above (1) is determined.
The specific gravity ρ' of the fuel in the fuel tank 60 is determined using the relationship of the formula. After step 118, step 120
Proceed to and use the following equation to determine the fuel temperature in the tank.
Convert it to the standard gravity ρ using THF ₀ and store it in the backup RAM. ρ←ρ′{1+(THF ₀ −15)/1000} ………(2) After step 120, or after step 114,
If the determination result in step 116 is negative, this one second routine is terminated. Calculation of the correction amount Δq for each cylinder and the correction amount ΔQp for each cylinder according to the fuel temperature THF in the pump and the specific gravity ρ of the fuel determined by the 1-second routine as described above is as follows.
The input capture interrupt routine ICI is executed every 45° CA as shown in FIG. That is, at the falling edge of the NE pulse output from the engine rotation sensor 22 at every crank angle of 45° CA, step 210 is entered, and as shown in FIG.
From the time interval ΔT until the falling edge of the NE pulse,
Calculate the engine rotation speed NEi (i=1 to 4) for each 45° CA. Since the counter i is updated in the order of 1 → 2 → 3 → 4 → 1 as the NE pulse falls, the engine rotation speed NEi also changes NE ₁ → every 180° CA.
NE ₂ → NE ₃ → NE ₄ → NE ₁ will be completed and saved in each memory. Next, proceed to step 212, and as shown in the following equation,
Calculate the average engine speed NE between 180°CA. NE=(NE ₁ +NE ₂ +NE ₃ +NE ₄ )/4
......(3) Next, the process proceeds to step 214, where the counter i is updated, and then, in step 216, from the map having the relationship as shown in FIG. A correction coefficient K ₅ is calculated according to the engine speed NE to prevent hunting when the engine speed is relatively high. Next, the process proceeds to step 218, where it is determined whether the count value of counter i is 4 or not. If the determination result is positive, that is, if the counter i has just been updated from 3 to 4, the process proceeds to step 220, where it is determined whether the idle state is stable. If the determination result is positive, _the process proceeds to step 222, where the engine speed NE ₁ is set to
It is determined whether the state with the minimum value among NE ₄ is two or more cylinders. If the judgment result is positive,
That is, when it is determined that no misfire has occurred and the rotation is stable, the process proceeds to step 224,
As shown in FIG. 4, the rotational fluctuation DNEp (p=1 to 4) corresponding to each cylinder is calculated using the following equation and stored in each memory. DNEp←NE ₃ −NE ₁ ………(4) Here, counter p corresponds to each cylinder, and when counter i goes from 4 to 1, 1 → 2 → 3 →
It has been updated from 4 to 1, making it rotate around 720° CA. The process then proceeds to step 226, where the average rotational variation WNDLT is calculated using the following equation and stored in memory. WNDLT← ₄ 〓 ^P=1 DNEp/4 ………(5) Next, proceed to step 228, and use the following formula to calculate the average rotational fluctuation WNDLT and the rotational fluctuation DNEp of each cylinder.
Calculate the deviation DDNEp from DDNEp←WNDLT−DNEp (6) Next, the process proceeds to step 230, and according to the rotational fluctuation deviation DDNEp calculated in step 228, for example, from the relationship shown in FIG. , calculate the correction amount Δq each time. Δq=f(DDNEp) ......(7) Next, proceed to step 232, and as shown in the following equation,
The currently determined correction amount Δq for each cylinder is integrated into the cylinder-specific correction amount ΔQp, which is the cumulative value up to the previous time, and is stored as the current value. ΔQp←ΔQp+Δq (8) Note that there are four cylinder-specific correction amounts ΔQp, ΔQ ₁ to ΔQ ₄ , since they correspond to each cylinder. After completing step 232, proceed to step 234,
The upper limit guard value ΔQpmax of the correction amount for each cylinder is calculated based on the relationship shown in FIG. 16, for example, according to the pump internal fuel temperature THF and the specific gravity ρ of the fuel, which are determined in advance in the one-second routine. Next, the process proceeds to step 236, where it is determined whether the cylinder-specific correction amount ΔQp calculated in step 232 is greater than its upper limit guard value ΔQpmax. If the determination result is positive, the process proceeds to step 238, sets the upper limit guard value ΔQpmax as the cylinder-specific correction amount ΔQp, and ends this interrupt routine ICI. On the other hand, if the determination result in step 236 is negative, the process proceeds to step 240, where a lower limit guard value ΔQpmin of the cylinder-specific correction amount is calculated according to the pump internal fuel temperature THF and fuel specific gravity ρ. Next, the process proceeds to step 242, where it is determined whether the cylinder-specific correction amount ΔQp is less than or equal to its lower limit guard value ΔQpmin. If the judgment result is positive, step 244
Then, the lower limit guard value ΔQpmin is set as the cylinder-specific correction amount ΔQp, and this interrupt routine ICI is ended. If the determination result in step 242 is negative, the cylinder-by-cylinder correction amount ΔQp obtained in step 232 is used as is, and this interrupt routine ICI is terminated. On the other hand, if the determination result at step 218 is negative, the process proceeds to step 250, where it is determined whether the count value of counter i is 2 or not. If the judgment result is positive, that is, the count value of counter i changes from 1 to 2.
If it is determined that the current value has just been updated, the process advances to step 252 and the counter p is updated. After step 252 is completed, or if the judgment result in step 250 is negative, the process proceeds to step 254, where the average engine speed NE and accelerator opening are determined by a known injection amount calculation routine as shown in the following equation. Degree Accp
The final injection amount Qfin' is obtained by adding the cylinder-specific correction amount ΔQp ₊₁ multiplied by the correction coefficient _K5 to the injection amount Qfin obtained from the equation. Qfin′←Qfin＋K ₅ ×ΔQp ₊₁ ………(9) After step 254 or the above step 220,
If the determination result at step 222 is negative, this interrupt routine ICI is ended. In this example, fuel type and cylinder-specific correction amount ΔQp when the pump internal fuel temperature THF is -10°C
FIG. 17 shows an example of the relationship between the upper and lower limit guard values ΔQpmax and ΔQpmin. As is clear from the figure,
When using special No. 3 diesel oil (ρ = 0.809), the cylinder-specific correction amount ΔQp is the upper and lower limit guard value, for example ±2 mm.
Even if the cylinder moves to ³ /st, the spill ring can almost follow it, so it does not interfere with the correction control of the next cylinder. On the other hand, when using No. 2 diesel oil (ρ = 0.833), the upper and lower limit guard values ΔQpmax and ΔQpmin are, for example, ±1
Since it is suppressed to mm ³ /st, it does not interfere with the correction control of the next cylinder. Therefore, correction control for each cylinder is reliably performed regardless of the type of fuel. In this embodiment, the specific gravity ρ' of the fuel determined from the output of the hydrometer 64 is converted to the standard state value ρ, so that the specific gravity of the fuel can be determined with high accuracy. can be highly controlled. Furthermore, in this embodiment, a bubble tube type hydrometer is used as the hydrometer 64, so the cost is low.
It also has excellent mounting properties. Furthermore, it is not affected by changes in suspended matter or liquid level. Note that the type of hydrometer is not limited to this. In this embodiment, the present invention was applied to an electronically controlled automobile diesel engine equipped with a spill ring as a fuel injection amount control actuator, but the scope of application of the present invention is not limited to this, and other It is clear that the present invention can be similarly applied to general electronically controlled diesel engines equipped with a type of fuel injection amount control actuator.

【Effect of the invention】

As explained above, according to the present invention, it is possible to always keep the cylinder-specific correction amount within a range that can be followed by the fuel injection amount control actuator, regardless of the specific gravity of the fuel or changes in this specific gravity due to temperature changes. can. Therefore, even when using fuel with high viscosity such as No. 2 light fuel when cold or when using fuel with high specific gravity, divergence of the correction amount can be prevented, and the correction of the previous cylinder is used for correction of the next cylinder. The injection amount can be reliably corrected for each cylinder without interference, and the vibration level can be minimized. In particular, since not only the temperature of the fuel but also the specific gravity is taken into consideration, the viscosity of the fuel can be estimated accurately, making it possible to control with even higher precision. In addition, quality standards for variations in the injection amount between cylinders of the fuel injection pump and variations in the valve opening pressure of the injection nozzle can be relaxed, and there are excellent effects such as cost reduction.

[Brief explanation of drawings]

Figure 1 is a diagram showing the relationship between rotational fluctuations and crank runout undulations in a conventional electronically controlled diesel engine, and Figure 2 shows the configuration of an engine rotation sensor used in a conventional electronically controlled diesel engine. The cross-sectional view shown in FIG. 6 to 8 are diagrams showing examples of signal waveforms of various parts in the conventional example, FIG. 9 is a flowchart showing the gist of the fuel injection amount control method for each cylinder of an electronically controlled diesel engine according to the present invention, and FIG. The figure is a sectional view, including a partial block diagram, showing the overall configuration of an embodiment of an electronically controlled diesel engine for automobiles in which the present invention is adopted. 12 is a block diagram showing the structure of the electronic control unit; FIG. 13 is a flowchart showing a 1-second routine for determining the fuel temperature in the pump and the specific gravity of the fuel; 14th
Similarly, the figure is a flowchart showing an interrupt routine for determining the correction amount each time and the correction amount for each cylinder, and FIG. 15 is a diagram showing an example of a map for determining the correction coefficient used in the interrupt routine. , 1st
Similarly, Fig. 6 is a diagram showing an example of the relationship between the specific gravity and temperature of fuel and the upper and lower limit guard values of the correction amount for each cylinder, and Fig. 17 is a diagram showing the relationship between the type of fuel, the correction amount for each cylinder and its FIG. 3 is a diagram showing an example of the relationship between upper and lower limit guard values. 10...Engine, 12...Fuel injection pump,
22... Engine rotation sensor, 24... Pump plunger, 32... Spill ring, 34... Spill actuator, 36... Spill position sensor,
44... Injection nozzle, 56... Accelerator sensor, 58... Pump fuel temperature sensor,
THF... Fuel temperature in pump, 60... Fuel tank, 62... Tank fuel temperature sensor, THF ₀ ...
Fuel temperature in tank, 64...Hydrometer, ρ, ρ'...
Specific gravity of fuel, 68...Electronic control unit (ECU), NEi...45°CA engine rotation speed,
DNEp...Engine speed fluctuation, WNDLT...Average speed fluctuation, DDNEp...Rotation fluctuation deviation, Δq...
Each time correction amount, ΔQp...Cylinder-specific correction amount, ΔQpmax
...Upper limit guard value, ΔQpmin...Lower limit guard value,
Qfin, Qfin′...Injection amount.

Claims (1)

[Claims] 1. Detecting and comparing the rotational fluctuations of each explosion cylinder, controlling the fuel injection amount control actuator for each cylinder so that the rotational fluctuations of each cylinder are uniform, and reducing the variation in the fuel injection amount between the cylinders. In a method for controlling fuel injection amount by cylinder of an electronically controlled diesel engine that suppresses engine vibration due to A procedure for determining a cylinder-specific correction amount of a fuel injection amount control actuator; A procedure for detecting fuel specific gravity and temperature; and Converting the detected fuel specific gravity to a standard state using the detected fuel temperature. a procedure for determining the upper and lower limit guard values of the cylinder-specific correction amount, which vary according to the viscosity of the fuel; A method for controlling fuel injection amount by cylinder in an electronically controlled diesel engine, comprising: a step for controlling a fuel injection amount control actuator for each cylinder by a limited correction amount for each cylinder. 2. The fuel injection amount control method for each cylinder of an electronically controlled diesel engine according to claim 1, wherein the absolute value of the upper and lower limit guard values is made smaller when the specific gravity of the fuel is high.