JPH0363665B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for an internal combustion engine, and more specifically, it is capable of stably and accurately controlling the amount of fuel supplied to an internal combustion engine. The present invention relates to an electronically controlled internal combustion engine control device.

(Prior Art) For example, in a conventional electronically controlled fuel injection control device for a diesel engine, a target signal indicating the target injection amount at any time is obtained in response to an input signal indicating the operating state of the diesel engine, and a target signal indicating the target injection amount at the time is obtained. A closed loop control system is employed to operate a fuel adjustment member provided in the fuel injection pump so that a feedback signal indicating the actual injection amount of the injection pump matches a target signal. Such a closed loop control system is disclosed in, for example, Japanese Patent Laid-Open No. 57-32025, Japanese Patent Laid-Open No. 57-32026, and Japanese Patent Laid-Open No. 57-32027.

(Problem to be Solved by the Invention) In recent years, many devices have been used that implement such control systems using, for example, digital microcomputers. As a result of being updated intermittently, various problems occur in the closed loop control operation. For example, if the actual injection amount is calculated based on the injection pressure, the closing time of the injection valve, the lift time of the needle valve of the injection nozzle, etc., in a digital control system,
These data are updated at every predetermined timing, for example at every fuel injection timing. Therefore,
Even if a control error occurs when a control output is obtained based on newly obtained input data and control is executed based on this, the presence or absence of a control error will not be known until the next time the data is updated. Since this cannot be corrected, the problem arises that control becomes unstable and control accuracy decreases, especially when the interval between data updates becomes long.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of closed-loop control in a control device for an internal combustion engine, and to perform stable and highly accurate control even when the necessary data for control is supplied intermittently. An object of the present invention is to provide a new control device for an internal combustion engine that can perform the following functions.

(Means for Solving the Problems) A feature of the present invention for achieving the above object is to control the fuel injection pump so that the amount of fuel supplied from the fuel injection pump to the internal combustion engine becomes a required target injection amount. An internal combustion engine control device that electronically controls an adjustment member, comprising an injection amount detection means for intermittently obtaining actual injection amount data indicating an actual injection amount supplied from the fuel injection pump at predetermined timings, and a target injection amount. a target position signal indicating a target position of the fuel adjustment member necessary to obtain the target injection amount in response to the actual injection amount data and the target injection amount data; a position detecting means for outputting an actual position signal indicating the actual position of the fuel adjustment member; and a position detecting means for outputting an actual position signal indicating the actual position of the fuel adjustment member, and for adjusting the actual position to match the target position in response to the target position signal and the actual position signal. The present invention includes calculation means for calculating a necessary control amount, and actuator means for controlling the position of the fuel regulating member in accordance with the control amount in response to the calculation means.

The actual injection amount can be detected based on, for example, the operating state of each part in the injection nozzle region, such as the lift amount of the needle valve,
It can be calculated from values such as valve opening time and injection pressure.

Further, the target injection amount can be calculated based on the values of various parameters indicating the operating state of the internal combustion engine. For example, the target value is calculated as the mass of fuel to be injected per stroke [mg/st], and this mass value is used as data indicating the fuel temperature from the fuel temperature sensor and data indicating the rotational speed of the internal combustion engine. Corrected based on the volume per stroke [mm ³ /st]
, and this may be used as data indicating the target injection amount. Through the calculations described above, it is possible to easily correct for changes in fuel temperature, and more accurate control can be expected.

The control device according to the present invention is not limited to control for performing speed governing control according to a predetermined governor characteristic curve, but can be used to perform idling rotational speed control or constant vehicle speed control during idling operation. be able to.

(Function) The target position of the fuel adjustment member is determined from the data indicating the actual fuel injection amount obtained intermittently and the data indicating the target injection amount, and the next time the data indicating the actual fuel injection amount is updated. Until the timing, the position of the fuel adjustment member is controlled by a position control system that feeds back a signal indicating the actual position of the fuel adjustment member so that the target position is maintained.

(Example) Hereinafter, the present invention will be explained in detail with reference to an illustrated example.

FIG. 1 shows a block diagram of an embodiment of a control device for an internal combustion engine according to the present invention. The internal combustion engine control device 1 is a device for electronically controlling fuel injected from the fuel injection pump 2 to the diesel engine 3, and includes a target injection amount calculation circuit 4. The target injection amount calculation circuit 4 uses speed data D ₁ indicating engine speed and an accelerator pedal (not shown).
in response to accelerator data D ₂ indicating the operation amount of , water temperature data D ₃ indicating the cooling water temperature of the diesel engine 3,
The target injection amount, which is the amount of fuel required to perform speed control according to the required governor characteristics, is mapped using the ROM. Therefore, the ROM (not shown) in the target injection amount calculation circuit 4 contains data D ₁ , D ₂ ,
Target injection amount data D ₃ with values corresponding to those data contents are placed at the address indicated by D ₃ .
Stored as a value indicating the weight of fuel required per stroke. Therefore, each data D ₁ , D ₂ ,
The target injection amount data Da corresponding to the combination of D ₃ can be read from the ROM by applying the data D ₁ , D ₂ , D ₃ as address data to the ROM, and the read target injection quantity data
Da is applied to the correction circuit 5.

The correction circuit 5 converts the target injection amount represented by the weight of the injected fuel per stroke into corrected target data Db representing the volume of the injected fuel per stroke, taking into consideration the fuel temperature and engine speed at the time. ,
This is a circuit for correction, and speed data _D1 and fuel temperature data _D4 indicating the temperature of the fuel are input. The above conversion and correction in the correction circuit 5 are as follows:
This is done based on the formula below.

Db=Da+α(t _Q −t _p ) In other words, the fuel temperature t _Q at that time and the predetermined reference temperature
By adding the difference from t _O multiplied by a coefficient α determined by the value of the engine speed N at that time to the target injection amount data Da displayed in weight, data conversion,
The correction is performed to obtain corrected target data Db that is corrected for the injection amount and fuel temperature at that time.
As shown in FIG. 2, the value of the coefficient α is determined to decrease as the engine speed N increases and to increase as the injection amount Q increases.

On the other hand, the injection nozzle 6 provided in the predetermined cylinder of the diesel engine 3 is
It has a built-in sensor (not shown) to detect the wrist amount of the needle valve, and the output signal from the sensor
_S1 is input to the actual injection amount calculation circuit 7. The output signal _S1 is a signal whose level changes according to the lift amount of the needle valve (see Fig. 4a), and the actual injection amount calculation circuit 7 calculates the actual injection amount based on the level change of the output signal _S1 . The amount of fuel injected is calculated, and the result of this calculation is output as actual injection amount data Dc expressed in volume per stroke.

FIG. 3 shows a detailed block diagram of the actual injection amount calculation circuit 7.

The output signal S ₁ which is an analog signal is input to the sampling circuit 21 and sampled by the pulse signal P ₁ output from the rotation pulse generator 22 . The pulse signal _P1 is a pulse train signal consisting of pulses output every time the crankshaft of the diesel engine 3 rotates by a predetermined angle. The sampling result from the sampling circuit 21 is output as a sampling signal H consisting of sampling data H ₁ , H ₂ , .
is input.

The calculation circuit 23 is a circuit for converting the needle valve lift amount L of the injection nozzle 6 into the opening area A of the injection nozzle at that time. (see Fig. 5) is stored, and each time each sampling data H ₁ , H ₂ , ... is input, machining area data A ₁ , corresponding to the value of each sampling data is stored.
Output A ₂ ,... After the lift amount data is converted into opening area data in this manner, the opening area data A ₁ , A ₂ , . . . are input to the integrating circuit 24 .

The integration circuit 24 calculates the actual opening area by time-integrating all the opening area data A ₁ , A ₂ . Since there is a predetermined functional relationship with the fuel injection amount, the output from the integrating circuit 24 is output as the injection amount signal Sa indicating the injection amount from the injection nozzle. In order to ensure that all the opening area data A ₁ , A ₂ , ...An obtained in one fuel injection operation can be time-integrated in the integration circuit 24, the integration circuit 24 has a function that controls the start of integration of the integration circuit 24 and Control signal to control the end of integration
Bb is input from the integral control circuit 25.

The integral control circuit 25 determines the timing of the start of integration at the injection start point based on a signal from a crank angle sensor (not shown) of the engine crankshaft.
Detect a time t ₀ that is a little earlier than t ₁ (see Figure 4 a) and set it to t ₀ to set the timing of the end of the integration to 1.
The configuration is such that the time t ₂ is set at the elapsed time T ₀ which allows a sufficient margin for the time T required for one injection.

As a result, the integrating circuit 24 receives the total aperture area data.
A ₁ , A ₂ , ...An can be reliably integrated.
In this way, the injection amount signal Sa is obtained according to the opening area calculated based on the actual lift amount of the needle valve, and the injection amount signal Sa is digitized by the analog-digital (A/D) converter 26. ,
It is output as injection amount data Dc.

Returning to FIG. 1, the corrected target data Db and the actual injection amount data Dc are added in the adder 8 with the polarity shown, and the error data Dd indicates the addition result.
is input to the PID control circuit 9, signal processing necessary to perform proportional, integral and differential control is performed on the error data Dd, and the PID control circuit 9 outputs a target position signal _S2 .

The target position signal S ₂ is an analog signal indicating the target control position of the fuel adjustment member, and is applied to a position signal loop comprising a position signal generation circuit 10 that outputs an actual position signal S ₃ indicating the position of the fuel adjustment member. has been done.

A fuel adjustment member (not shown) provided within the fuel injection pump 2 is connected to and driven by the electromagnetic actuator 11 . In order to electrically detect the position of the fuel adjustment member, a sensor coil 12 is connected to the electromagnetic actuator 11, and its inductance changes depending on the position of the fuel adjustment member, thereby generating a position signal connected to the sensor coil 12. Generation circuit 10
, an actual position signal _S3 whose level changes depending on the position of the fuel adjustment member is output. Real position signal S ₃
is input as a feedback signal to the adder 13, the target position signal _S2 and the actual position signal _S3 are added with the polarity shown, and the output signal _S4 of the addition result is sent to another PID control circuit 15. has been entered.
The PID control circuit 15 performs signal processing necessary to perform proportional, integral, and differential control on the output signal _S4 , and the resulting output signal _S'4 is sent to the pulse width modulation circuit 14 as a pulse width control signal. is entered as .

The pulse width modulation circuit 14 is a circuit that outputs a pulse signal whose pulse width is modulated according to the level change of the output signal _S'4 . This pulse width modulation circuit 14
Accordingly, a drive pulse signal S 5 whose duty ratio is controlled according to the level of the output signal S' ₄ is output as a signal indicating a controlled amount, and the drive pulse signal _{S 5 is} applied to the electromagnetic actuator 11. Therefore, the positioning operation of the fuel adjusting member by the electromagnetic actuator 11 is performed in accordance with the level of the output signal _S'4 .

According to such a configuration, the target fuel injection amount is determined in response to the corrected target data Db output from the correction circuit 5 as data indicating the target injection amount and the actual injection amount data Dc from the actual injection amount calculation circuit 7. a target position signal indicating the position of the fuel adjustment member needed to obtain
S ₂ is calculated. Since this target position signal _S2 is calculated based on the actual injection amount data Dc obtained at predetermined time intervals, this target position will remain unchanged until the next actual injection amount data Dc is obtained after the predetermined time has elapsed. is constant. Then, based on the difference between the target position signal S ₂ obtained in this way and the actual position signal S ₃ which is a continuous analog signal, positioning control of the fuel adjustment member is performed by the pulse drive signal S ₅ , and the actual injection The position of the fuel adjustment member can be maintained at the position indicated by the target position signal _S2 until the quantity data Dc is updated.

As a result, it is possible to determine the position of the fuel adjustment member necessary to obtain the required target injection amount according to the actual fuel injection amount, making it possible to perform more accurate fuel control, and to determine the next actual injection amount. Until the calculation of the data Dc is executed, the position of the fuel adjustment member is maintained at the target position of the fuel adjustment member determined as described above by the feedback control system that feeds back the actual position signal. . Therefore, even if, for example, the position of the fuel adjustment member shifts due to vibration or the like and the desired injection amount cannot be obtained, this feedback control system will keep the fuel adjustment member at the position indicated by the signal _S2 . The supply of the injection amount indicated by the data Db is maintained until the data Dc is updated. Therefore, even if the update interval of actual injection data used for injection amount control becomes longer, control accuracy can be maintained and control with good stability can be achieved. In this case, the positioning control that operates in response to the target position signal S ₄ and the actual position signal S ₃ only needs to ensure the stability of the control until the input data is updated, so the control accuracy is particularly high. is not required, and highly stable control can be achieved without a significant increase in cost.

Furthermore, in the above embodiment, the calculation of the target injection amount is as follows:
The process is first performed in the dimension of mass, and then the mass is converted into volume taking into account the fuel temperature and engine speed, and the injection amount is determined in response to the volume-converted correction target data and the data indicating the actual injection amount. Since the control amount is determined, there is no need for tables, etc. to detect the position of the electromagnetic actuator and convert the detected position to the actual injection amount, and even if mechanical wear occurs in each part, this will cause control errors. It has the advantage that there is no problem.

Further, by providing appropriate target data instead of the data Da indicating the target injection amount, idle speed control, constant vehicle running control, etc. can be similarly achieved.

(Effects of the Invention) According to the present invention, as described above, the target position of the fuel adjustment member is determined from the data indicating the actual fuel injection amount obtained intermittently and the data indicating the target injection amount, and the actual fuel injection amount is determined. The position of the fuel adjustment member is controlled by a position control system that feeds back a signal indicating the actual position of the fuel adjustment member so that this target position is maintained until the next timing when the data indicating the injection amount is updated. Since it is configured to perform control, it is possible to expect highly accurate control based on the actual injection amount, and even if the update interval of input data regarding the actual injection amount necessary for control becomes longer, the fuel adjustment member Feedback position control provides excellent effects such as improved control stability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Figure 2 is a characteristic diagram of the coefficient α, Figure 3 is a detailed block diagram of the actual injection amount calculation circuit shown in Figure 1, and Figure 4 a.
4b is a signal waveform diagram for explaining the operation of the circuit shown in FIG. 3, and FIG. 5 is a characteristic diagram showing the relationship between the lift amount and opening area of the injection nozzle. DESCRIPTION OF SYMBOLS 1... Internal combustion engine control device, 2... Fuel injection pump, 3... Diesel engine, 4... Target injection amount calculation circuit, 5... Correction circuit, 7... Actual injection amount calculation circuit, 10... Position Signal generation circuit, 11... Electromagnetic actuator, 12... Sensor coil, D ₁ ...
Speed data, D ₂ ... accelerator data, D ₃ ... water temperature data, D ₄ ... fuel temperature data, Da ... target injection amount data, Db ... corrected target data, Dc ... actual injection amount data, S ₁ ...Output signal, S ₃ ...Position signal,
_S5 ...Drive pulse.

Claims (1)

[Claims] 1. In an internal combustion engine control device that electronically controls a fuel adjustment member of the fuel injection pump so that the amount of fuel supplied from the fuel injection pump to the internal combustion engine becomes a required target injection amount, injection amount detection means for intermittently obtaining actual injection amount data indicating the supplied actual injection amount at predetermined timing; means for outputting target injection amount data indicating the target injection amount; means for outputting a target position signal indicating a target position of the fuel adjustment member necessary to obtain the target injection amount in response to target injection amount data; and outputting an actual position signal indicating the actual position of the fuel adjustment member. a position detection means for
calculating means for calculating a control amount necessary to make the actual position coincide with the target position in response to the target position signal and the actual position signal; 1. A control device for an internal combustion engine, comprising: actuator means for controlling according to a control amount.