JPH0754104B2 - Fuel injection amount control method - Google Patents

Description

The present invention relates to a rotation mechanism, for example, a rotation timing detection device for an internal combustion engine or the like. In particular, the present invention relates to an apparatus having a pulse output rotation angle sensor for detecting whether or not a rotation mechanism that causes rotation fluctuation during one cycle has reached a desired rotation angle phase.

[Prior Art] In some cases, an electromagnetic spill valve is used to control the injection end of a fuel injection pump of a diesel engine. The spill timing is calculated based on the operating state of the diesel engine, for example, the depression amount of the accelerator pedal + the engine rotation speed, and is represented by the corresponding engine rotation angle phase.

By the way, usually, the rotation angle phase of the engine is detected by a pickup provided close to the rotation of a rotor having a gear-like protrusion provided on the engine output shaft or the drive shaft of the fuel injection pump at the periphery, and the protrusion is approached. The + separation is taken as a pulse signal. That is, a pulse signal whose time interval becomes shorter according to the rotation speed is used. If this pulse number is counted from the reference pulse, the current rotation angle phase is known, and it is possible to spill at the timing when the desired angle phase is reached, but the desired angle phase exists between the pulses. In the case of, the time interval between the previous pulses, usually the pulse in which the previous desired angular phase was present, is measured, and the desired angle is calculated from the rotation angle between the two pulse outputs and the angular phase of the last pulse. The time to reach the desired angle phase is calculated using the angle difference up to the angle phase.

In this way, usually, it is possible to relatively accurately capture the timing when the desired angular phase between the pulses is reached.

[Problems to be Solved by the Invention] However, an internal combustion engine such as a diesel engine + gasoline engine, and other rotating mechanisms such as an electric pump may generate load timing due to exhaust or output due to explosion even during one cycle. The rotation speed varies depending on the timing.

In such a situation, if the desired angle phase is detected as described above, the desired angle phase changes for each cycle. Since the time interval up to the angle phase uses the time interval between the pulses in which the previous desired angle phase exists, the phase between the pulses of the previous time and this time may be different in one cycle.

In this case, the phases of the load timing and the output timing are different, and it is not always the case that the rotation speed data under the same rotation fluctuation is used, and the calculation is performed using the previous pulse time interval. An error occurs due to the difference in rotation speed, and the fuel injection amount becomes inaccurate,
There was a risk that the rotation would become unstable and the emission would decrease.

An apparatus for correcting the time interval between pulses by obtaining the rotation change rate based on the relationship between the immediately preceding rotation speed and the average rotation speed in the vicinity of a desired rotation angle phase in consideration of this variation (Japanese Patent Laid-Open No. 60-17252). ) Was also proposed, but it was still not sufficient to absorb the fluctuation in the desired rotation angle phase.

〔means〕

In the present invention, since the spill signal is output at a desired spill angle of the electromagnetic spill type fuel injection pump and the high pressure fuel overflows to stop the fuel injection, a reference angle signal output at a predetermined reference angle and a predetermined rotation Using an angle signal output for each angle, from the time of generation of the reference angle signal to the angle signal immediately before the spill angle, the rotation angle is counted by the number of generations of the angle signal, and the remaining angle up to the remaining spill angle. Is a fuel injection amount control method in which the rotation angle is converted to time and the spill signal is output. In the fuel injection amount control method, the spill signal in the immediately preceding injection is formed by two angle signals sandwiching the output rotation angle. The interval time (Ts2) of the first section, the interval time (Ts1) of the second section formed by the angle signal adjacent immediately before the first section, and the angle signal adjacent immediately after the first section The third section formed by Stores interval time (Ts3), respectively, among the first to third section immediately before injection,
To select a section formed by the same angle signal as the angle signal immediately before the spill angle and the next angle signal in this injection, and convert the remaining angle into time based on the interval time of the selected section. Is used for controlling the fuel injection amount.

[Action]

As a premise of the present invention, the rotation angle is counted by the number of generated angle signals from the generation time of the reference angle signal to the angle signal immediately before the spill angle, and the remaining angle up to the remaining spill angle is converted into time and the rotation angle is calculated. In the so-called angle-time conversion method for controlling the fuel injection amount that determines the spill signal and outputs the spill signal, it is necessary to decide at what point the generation interval of the angle signal that serves as a reference for the time conversion is determined. Is very important.

In the present invention, the measurement of the reference time for performing the angle-time conversion at the time of the spill this time is performed at the same position of the rotation angle of the injection pump by using the same rotation angle phase as the angle signal at the time of the spill in the immediately preceding injection. First, if there is a sudden rotation fluctuation during the period from the previous injection to the current injection, the current angle signal may not correspond to the angle signal when the spill signal is generated during the previous injection. For,
At the time of spill in the immediately preceding injection, in addition to the interval time of the first section formed by the two angle signals sandwiching the spill angle, the second section formed by the adjacent angle signal immediately before the first section.
The interval time of the section and the interval time of the third section formed by the adjacent angle signal immediately after the first section are stored in advance, and the corresponding interval time is selected at the time of this spill. Therefore, for example, even when the angle signal of the spill signal in this injection deviates from the previous angle signal by one, the reference time for calculating the remaining time in this spill does not disappear.

[Examples] Next, examples of the present invention will be described. The present invention is not limited to these, and includes various embodiments without departing from the scope of the invention.

FIG. 1 shows a schematic configuration of a fuel injection pump 1 according to an embodiment of the present invention.

The fuel injection pump 1 is an electromagnetic spill metering type fuel injection pump based on a Bosch type distributed fuel injection pump. The fuel injection pump 1 is driven by a drive shaft 2.
The vane feed pump 3 is rotated in conjunction with an engine (not shown).

The vane type feed pump 3 introduces the fuel in the fuel tank (not shown) from the suction port 4 through A through the filter A, pressurizes the fuel and adjusts it to the pressure set by the regulation valve 5, and then The fuel is supplied to a fuel chamber 6 formed in the injection pump 1.

The drive shaft 2 drives a plunger 8 via a coupling 7. This coupling 7 integrally rotates the plunger 8 in the rotation direction, but when the plunger 8 reciprocates in the axial direction, the axial movement is freely permitted. A face cam 9 is integrally provided on the plunger 8. The face cam 9 is pressed against the cam roller 11 by the spring 10, and the sliding contact between the face cam 9 and the cam roller 11 causes the plunger 8 to reciprocate when the cam ridges of these face cams 9 ride on the cam roller 11. The plunger 8 is reciprocated during one rotation a number of times (here, four times) according to the number of cylinders of the engine (not shown).

The plunger 8 is slidably and precisely fitted to a head 12 attached to the fuel injection pump 1, and the head 12 and the end surface of the plunger 8 form a pump chamber 13. A suction groove 14 is formed on the peripheral surface of the end portion of the plunger 8, and one of these suction grooves 14 is formed in the head during the suction stroke of the plunger 8, that is, during the movement to the left in FIG. When communicating with a suction port (not shown) provided in 12, fuel is sucked from the fuel chamber 6 into the pump chamber 13. Further, during the compression stroke of the plunger 8, that is, during the movement to the right in the drawing of FIG. 1, the fuel pressurized in the pump chamber 13 is pressure-fed to the injection passage 17 through the communication passage 19 and the distribution port 16 and discharged. Injection is made from B through the valve 18 into the combustion chamber of the engine by an injection valve not shown.

A spill type solenoid valve 20 is connected to the pump chamber 13. That is, the pump chamber 13 is communicated with the fuel chamber 6 through the overflow passages 21 and 22, and the overflow passage 21 is opened and closed by the solenoid valve 20. The solenoid valve 20 includes a needle valve 24 and a solenoid 25.
When the solenoid 25 is energized, the needle valve 24 is lifted and the pump chamber 13 overflows.
The fuel chamber 6 is opened via 21,22. Therefore, when the solenoid valve 20 is operated during the compression stroke of the plunger 8, the fuel pressurized in the pump chamber 13 escapes to the fuel chamber 6 on the low pressure side via the overflow passages 21 and 22, so that the injection passage It is no longer sent to the 17 side, and fuel injection is stopped. This controls the fuel injection amount to be supplied to the engine side.
A part of the fuel overflowing into the fuel chamber 6 is returned from C to a fuel tank (not shown).

The timing of starting energization of the solenoid valve 20 is performed by the electronic control circuit 26 including a microcomputer and the like.

The cam roller 11 described above is held by the roller ring 27. The roller ring 27 is operated by a fuel injection timing adjusting mechanism (timer) 30. Fuel injection timing adjustment mechanism 30
Is equipped with a timer piston 31, and the fuel pressure in the fuel chamber 6 acts on one end surface of the timer piston 31. Fuel chamber 6
Fuel pressure changes with half of the engine rotation speed, that is, according to the rotation speed of the feed pump 3. When the fuel pressure in the fuel chamber 6 acts on one end face of the timer piston 31, the timer piston 31 acts on the other face by a spring.
It is moved to the left in Fig. 1 against 32 forces. Such reciprocal movement of the timer piston 31 is transmitted to the roller ring 27 via the pin 33. In FIG. 1, the timer piston 31 is shown in a posture orthogonal to the actual case, and in reality, the timer piston 31 is mounted with the axis of the timer piston 31 oriented in a direction orthogonal to the plane of the drawing. Therefore, the reciprocating movement of the timer piston 31 causes the roller ring 27 to be rotationally displaced about the drive shaft 2. For this reason, the cam roller 11 and the face cam 9 are relatively displaced in the circumferential direction, so that the timing at which the cam crest of the face cam 9 rides on the cam roller 11 is deviated, and the phase of the reciprocating motion of the plunger 8 with respect to the drive shaft 2 changes. . As a result, the communication timing between the distribution port 16 and the injection passage 17 changes, so the fuel injection timing is automatically adjusted.

The roller ring 27 includes, for example, a rotation angle sensor such as an electromagnetic pickup type, a hall element type or an optical angle detecting type.
35 is attached thereto, while a pulsar 36 is fixed to the drive shaft 2. Rotation of drive shaft 2 causes pulsar
When one of the protrusions 37 formed on 36 crosses the rotation angle sensor 35, the rotation angle sensor 35 generates a signal. This signal is sent to the electronic control unit 26. Upon receiving the output signal from the rotation angle sensor 35, the electronic control unit 26 outputs a power signal for instructing the solenoid valve 20 to operate when a desired angular phase is reached based on this signal. Since the pulsar 36 is provided with a toothless portion to represent the reference angle phase and is configured to generate 32 signals per one revolution (360 ° CA) of the diesel engine, 11.25 ° CA between each pulse. Equivalent to.

When the roller ring 27 is rotated by the operation of the timer 30, the rotation angle sensor 35 is also rotated by the same phase as the roller ring 27. Therefore, when the fuel injection timing is adjusted, the reference signal sent to the electronic control unit 26 also shifts by the same phase, so the operation timing of the solenoid valve 20 changes, and the overflow timing also changes by the shift in the reciprocating timing of the plunger 8. Therefore, the injection amount does not change.

The electronic control circuit 26 is various sensors for detecting the operating state of the engine, for example, an accelerator opening sensor 41 for detecting the position (depression amount) of the accelerator pedal 40 and a rotation speed sensor (not shown) for detecting the rotation angle of the engine, Alternatively, an intake air temperature sensor or the like is connected and the rotation angle sensor
The output of 35 is connected and is combined with the pulsar 36 to detect a pulse signal corresponding to the rotational phase of the face cam 9 of the fuel injection pump 1 as described above. Further, the electronic control circuit 26 outputs a power signal for exciting the solenoid 25 to the spill solenoid valve 20 after a preset time period has elapsed or after a time period calculated from various conditions has elapsed, to open / close the solenoid valve 25. To do.

The electronic control circuit 26 is configured as a logical operation circuit centering on a CPU 26a, ROM 26b, RAM 26c, backup RAM 26d, etc., and an input unit 26f and an output unit 26g via a common bus 26e.
Is connected to and receives a pulse signal from the rotation angle sensor 35, an opening signal of the accelerator opening sensor 41, and other output signals of the intake air temperature sensor and the like, and outputs a control signal to the solenoid valve 20.

Next, the spill timing determination process executed by the electronic control circuit 26 will be described. FIG. 2 shows a flowchart thereof. This process is a routine that is executed every time a pulse signal is input from the rotation angle sensor 35. Further, FIG. 3 shows a timing chart of the pulse signal and the spill solenoid valve signal when this processing is executed.

First, in step 90, the pulse time interval T _S from the immediately preceding pulse is measured as the measured value of this cycle, and RAM2
Store in 6c. Next, at step 100, the accelerator opening degree calculated based on the engine speed Vθ already calculated based on the pulse signal of the rotation angle sensor 35 in another routine and the output of the accelerator opening sensor 41. The spill command angle θ _FIN is obtained from θ _ACC and by interpolating from the map stored in the ROM 26b. Next, at step 110, the spill command angle θ _FIN is separated into an integer quotient n by the pulse output angular interval of 11.25 ° CA and a remainder angle θ _R.

Next, in step 120, the value of the quotient n is checked. If n = 5, the processing of step 130 is performed, if n = 6, the processing of step 140 is performed, and if n = 7, the processing of step 150 is performed. Is done. That is, in step 130, θ _R is converted into the rotation time T _SPON at the time interval T _S1 between the pulse signal of # 5 and the pulse signal of # 6 in the previous cycle. Similarly, in step 140, # 6 pulse signal of the previous cycle and #
Rotation time T with θ _R at time interval T _S1 with the pulse signal of 7
Convert to _SPON . Further, in step 150, the time interval between the pulse signal of # 7 and the pulse signal of # 8 in the previous cycle is set.
At T _S1 , convert θ _R to rotation time T _SPON .

Here, n is limited to 5, 6 and 7, but normally n falls within that range. Of course, n may be made wider if necessary. That is, all pulse intervals may be measured and stored.

Next, at step 160, the value of n is set in the angle counter in the RAM 26c, and the value of T _SPON is set in the time counter in the RAM 26c. Next, at step 170, when the pulse signal of # 0 serving as the reference is counted to reach #n, time is started to be counted, and when the rotation time T _{SPON has} elapsed, the spill solenoid valve 20 is opened. In this way, fuel injection is accurately stopped at the spill command angle θ _FIN , and a desired fuel amount can be supplied to the diesel engine.

In this embodiment, not only is the pulse interval only stored during spilling as described above, but the pulse intervals before and after that are also stored, and rotation is performed at the previous pulse interval corresponding to the time of this spill. Since the time T _SPON is calculated, it is possible to always accurately spill to the desired rotation angle phase even under the rotation fluctuation associated with the engine stroke peculiar to the reciprocating engine.

〔The invention's effect〕

As described above, according to the present invention, the interval time of the section formed by the angle signals sandwiching the spill angle at the time of the immediately preceding injection, which has the same phase as the spill angle of this time, is stored, and further, the interval time before and after the section exists The interval time is also stored, and the remaining time at the time of this spill is calculated by selecting the previous section that is the same as this time's spill angle, so the reference time does not exist even when the rotation suddenly changes. There is an excellent effect that the spill time can be accurately calculated based on the information of the rotation phase which is always close to the spill time.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a flow chart showing processing executed by an electronic control circuit, and FIG. 3 is a timing chart of pulse signals and spill solenoid valve signals. 1 ... Fuel injection pump, 20 ... Spill solenoid valve 26 ... Electronic control circuit, 35 ... Rotation angle sensor 41 ... Accelerator pedal sensor

Front page continuation (72) Inventor Hiroki Mori 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd. (56) Reference JP 62-267547 (JP, A) JP 60-17252 ( JP, A) JP 63-150452 (JP, A)

Claims (1)

[Claims] 1. A reference angle signal output at a predetermined reference angle and a predetermined reference angle signal for outputting a spill signal at a desired spill angle of an electromagnetic spill type fuel injection pump to cause high pressure fuel to overflow and stop fuel injection. Using the angle signal output for each rotation angle, the rotation angle is counted by the number of the generated angle signals from the generation time of the reference angle signal to the angle signal immediately before the spill angle, and the remaining spill angle remains. In the method of controlling the fuel injection amount in which the rotation angle is converted to time to determine the rotation angle and the spill signal is output, the spill signal in the immediately preceding injection is formed by two angle signals sandwiching the rotation angle. The interval time (Ts2) of the first section, the interval time (Ts1) of the second section formed by the angle signal adjacent immediately before the first section, and the interval time immediately after the first section. Third zone formed by angle signals Stores the interval time (Ts3), respectively, among the first to third section immediately before injection,
To select a section formed by the same angle signal as the angle signal immediately before the spill angle and the next angle signal in this injection, and convert the remaining angle into time based on the interval time of the selected section. A method for controlling a fuel injection amount, characterized by: