JPH0569976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an improvement in a fuel injection device that controls the amount of fuel injection based on the amount of air flowing into an internal combustion engine.

Prior art and problems Internal combustion engines such as automotive engines have a sensor that detects the amount of incoming air, calculates the fuel injection amount based on the detection result of the sensor, and calculates the amount at the fuel injection timing. Fuel injection devices that inject an amount of fuel corresponding to the result have been used in the past. In such a fuel injection system, acceleration, deceleration characteristics, drivability, and exhaust gas transient characteristics are affected by the reading timing and calculation timing of sensor detection results, so setting these timings is an important issue. It is.

FIGS. 1A to 1D are explanatory diagrams of a conventional example called an asynchronous method, and FIG. 1A shows a top dead center signal TDC,
B in the same figure shows the reading timing of the detection result of the sensor, C in the same figure shows the calculation timing, and D in the same figure shows the timing of fuel injection.

In this method, as shown in Figures B and C, the sensor detection results are read and the fuel injection amount is calculated based on the reading results at fixed time intervals T. For example, as shown in Figure D, the top dead center signal is " This method injects fuel for a time corresponding to the latest calculation result from the timing when the value reaches 1", but it has the following drawbacks. In other words, this method reads sensor detection results at fixed time intervals T and calculates the fuel injection amount based on the reading results, and the delay time from the end of the calculation to the start of fuel injection varies. , the maximum T, so there was a drawback that injection control with good responsiveness in response to changes in the state of the internal combustion engine (for example, acceleration, deceleration, etc.) could not be performed.

Figures 2A to 2E are explanatory diagrams of another conventional example called the synchronous system, in which Figure A shows the top dead center signal, and Figure 2B shows the signal every time the crank rotates by a certain angle (30° in this case). FIG. 3C shows the timing of reading the sensor detection results, D shows the calculation timing of the fuel injection amount, and E shows the fuel injection timing.

As shown in Figures B to D, this method starts from the time when a specific rotation angle position signal (rotation angle position signal C ₉ in this case) is detected, reads the detection result of the sensor, and adjusts the fuel injection amount based on the reading result. perform calculations,
For example, as shown in Figure E, fuel is injected for a period of time corresponding to the latest calculation result from the timing when the top dead center signal becomes "1", but it has the following drawbacks.

The time from when the rotation angle position signal C ₉ is generated until the top dead center signal becomes "1" varies depending on the rotation speed of the internal combustion engine, and the higher the rotation speed, the shorter the above-mentioned time becomes. The time from the start of reading the results to the end of calculation of the fuel injection amount is always a constant time T ₁ regardless of the rotation speed, so
When the rotational speed is high, as shown in FIG. D, calculations E1 and E2 may not be completed even at the fuel injection timing (the timing when the top dead center signal becomes "1"). In such a case, operations E1, E2
The calculation results are used for the subsequent injections H1 and H2, as shown in Figure E, and the delay time from the end of the calculation to the start of fuel injection is large, so the internal combustion engine The drawback was that it was difficult to perform injection control with good response characteristics in response to state changes.
In order to improve these drawbacks, the rotation angle position signal
It is also possible to start reading the sensor detection results when a specific rotation angle position signal before C ₉ is detected, but in this case, if the internal combustion engine speed is low, the time from the end of calculation to fuel injection may be The drawback was that it was difficult to perform injection control with good responsiveness due to the large delay time.

In addition to this, fuel injection is started at the timing when the top dead center signal becomes "1", and
The process to determine the fuel injection amount (reading the sensor detection results and calculating the fuel injection amount based on the reading results) was started, and the calculation result was started from the timing when the top dead center signal became "1". A method has also been proposed in which fuel is injected for a specified amount of time, but if the fuel injection time corresponding to the calculation result is shorter than the time required for processing to determine the fuel injection amount (for example, during idling), the predetermined amount of fuel Even though the fuel has already been injected, the fuel continues to be injected until the above-mentioned process is completed, which has the disadvantage of poor fuel efficiency and the disadvantage that raw gas is exhausted.

OBJECTS OF THE INVENTION This invention is an attempt to improve the above-mentioned drawbacks of the present invention, and its purpose is to enable highly responsive injection control in response to changes in the state of the internal combustion engine.

Composition of the invention The present invention includes the following configuration.

A fuel injection device that injects fuel corresponding to an amount of air flowing into the internal combustion engine into the internal combustion engine at a predetermined timing, the fuel injection device including a sensor that detects the amount of air flowing into the internal combustion engine, and a plurality of crank angles. a calculation means that has a processing start timing corresponding to a predetermined processing start timing and calculates a fuel injection amount based on a detection result of the sensor at a predetermined processing start timing; and a processing start timing that is set according to the plurality of crank angles. Detection means for detecting the rotation speed of the internal combustion engine at a timing preceding the earliest processing start timing, and control such that the higher the rotation speed, the earlier the processing start timing based on the detection result of the detection means. The fuel injection device is characterized in that it comprises a timing control means and an injection means for injecting an amount of fuel into the internal combustion engine at a predetermined timing in accordance with the calculation result of the calculation means.

FIG. 7 is a block diagram of the present invention. sensor 100
detects the amount of air flowing into the internal combustion engine, and the calculation means 101 calculates the fuel injection amount based on the detection result of the sensor 100. The detection means 102 detects the rotation speed of the internal combustion engine, and the timing control means 103 controls the calculation means 1 based on the detection result of the detection means 102.
Controls the processing start timing of 01. The injection means 104 injects an amount of fuel corresponding to the calculation result of the calculation means 101 at a predetermined timing.

Embodiment of the Invention Fig. 3 is a configuration diagram of an embodiment of the present invention, in which 1 is an internal combustion engine, 2 is an air cleaner, 3 is an air amount sensor, 4 is a throttle chamber, 5 is an intake manifold, and 6 is an electromagnetic type. , 7 is a throttle valve, 8 is an AD converter, and 9 outputs a top dead center signal TDC as shown in Fig. 4A every time the crank reaches top dead center, and also outputs a top dead center signal TDC when the crank reaches 30°. A crank angle sensor 1 outputs rotation angle position signals C ₁ to C ₁₂ as shown in FIG.
0 is a microprocessor, 11 is a memory, 12 is a data input section, 13 is a data output section, and 14 is a down counter, which holds its output signal at "1" until the count value reaches "0". be.
Further, FIG. 5 is a flowchart showing the processing contents of the microprocessor 10, and the operation will be explained below with reference to FIG.

The microprocessor 10 receives the rotation angle position signal from the crank angle sensor 9 via the data input section 12.
When detecting that C ₅ has been added (step
S1), the internal clock starts counting (step S2), and then, when the rotation angle position signal _C6 is detected (step S3), the internal clock ends counting (step S4). In this case, the rotation angle position signal
The time between C ₅ and C ₆ becomes shorter as the rotation speed of the internal combustion engine increases, so the count value corresponds to the rotation speed of the internal combustion engine, and the smaller the count value, the higher the rotation speed. show. These steps S1 to S4 detect the rotation speed that precedes the earliest timing (at the time of generation of rotation angle signal C7) among multiple processing start timings (time of generation of rotation angle signals _{C7 to C10} ), which will be described later. A detection means is configured to detect the

Next, the microprocessor 10 accesses the memory 11 based on the count value, ie, the number of rotations,
Steps when any rotation angle position signal is detected.
It is determined whether to start the process in S8, that is, the timing to start the process (step S5). In this case, the memory 11 stores the count value and the rotation angle position signal number in correspondence as shown in FIG. The rotation angle position signal with the smaller number is selected. If the count value COU is, for example, K2≦COU<K1, it is determined that the process of step S8 is started when the rotation angle position signal _C9 is detected. Next, the microprocessor 10 sets the count value to "0" (step S6), and when it detects the rotation angle position signal C _N determined in step S5 (step S7), it controls the AD converter 8 and the data input section 12. air volume sensor 3 applied via
The detection result is read (step S8), and then the fuel injection amount is calculated based on the read result (step S8).
S9), then find the fuel injection time corresponding to the fuel injection amount found in step S9 (step S9).
S10). After that, when it is detected that a top dead center signal is applied from the crank angle sensor 9 via the data input section 12 (step S11), the microprocessor 10 adjusts the fuel injection time corresponding to the fuel injection time determined in step S10. A numerical value is determined and set in the down counter 14 (step S12), after which the process returns to step S1.

The down counter 14 increments its count value by 1 every time the clock signal CK is applied, and holds its output signal α at "1" until the count value reaches "0". 6 continues to inject fuel while the signal α is "1". Therefore, by setting a numerical value corresponding to the fuel injection time in the down counter 14 in step S12, the amount of fuel determined in step S9 will be injected into the internal combustion engine 1.

As described above, this embodiment includes steps S1 to S4.
The timing at which the process of step S8 is started is changed according to the count value, that is, according to the rotational speed of the internal combustion engine.As can be seen from FIG. 6, the higher the rotational speed is, the more the process of step S8 is started. The timing is made earlier, and the lower the rotation speed, the later the timing to start processing in step S8, so the delay time from the end of calculation of the fuel injection amount to the start of injection can be reduced, Therefore, injection control can be performed with better responsiveness than in the conventional example.

In the embodiment, the amount of air flowing into the internal combustion engine is detected by the air amount sensor 3, but it goes without saying that the amount of air flowing into the internal combustion engine may be detected by an air pressure sensor.

As explained above, according to the present invention, the timing for starting processing is set according to a plurality of crank angles, and the rotation is detected at a timing preceding the earliest processing start timing that can be set among the processing start timings. Since the optimal process start timing is carefully selected based on the number of processes, it is possible to start the process reliably without being affected by fluctuations in the rotation speed after the specific process start timing. The delay time from the end of the process until the fuel is injected can be made as short as possible regardless of the rotation speed of the internal combustion engine,
Therefore, there is an advantage that injection control can be performed with good responsiveness in response to changes in the state of the internal combustion engine.

[Brief explanation of drawings]

Figures 1 A to D and Figures 2 A to E are explanatory diagrams of different conventional examples, Figure 3 is a configuration diagram of an embodiment of the present invention, and Figures 4 A and B are top dead center signals and rotation angles, respectively. FIG. 5 is a flowchart showing the processing contents of the microprocessor, and FIG. 6 is a diagram showing the contents stored in the memory. FIG. 7 is a block diagram of the present invention. 1 is an internal combustion engine, 2 is an air cleaner, 3 is an air amount sensor, 4 is a throttle chamber, 5 is an intake manifold, 6 is a fuel injector,
7 is a throttle valve, 8 is an AD converter, 9 is a crank angle sensor, 10 is a microprocessor, 11 is a memory, 12 is a data input section, 13 is a data output section, 14 is a down counter, 100 is a sensor, 1
01 is a calculation means, 102 is a detection means, 103 is a timing control means, and 104 is a fuel injection means.

Claims (1)

[Claims] 1. In a fuel injection device that injects fuel corresponding to the amount of air flowing into the internal combustion engine into the internal combustion engine at a predetermined timing, the fuel injection device includes a sensor that detects the amount of air flowing into the internal combustion engine, and a plurality of cranks. a calculation means having a processing start timing according to the angle and calculating a fuel injection amount based on the detection result of the sensor at a predetermined processing start timing; a detection means for detecting the rotation speed of the internal combustion engine at a timing preceding the earliest processing start timing to be obtained, and control such that the higher the rotation speed, the earlier the processing start timing is based on the detection result of the detection means. A fuel injection device comprising: timing control means; and injection means for injecting an amount of fuel into the internal combustion engine at a predetermined timing in accordance with the calculation result of the calculation means.