JP2625018B2 - Electronic control engine control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically controlled engine control method using an intake pressure sensor, and more particularly to a failure judgment of an intake pressure sensor.

[Prior Art] Engine operating condition parameters such as intake pressure and engine speed are detected by respective sensors, and a microcomputer is used to determine a control amount such as a fuel supply amount and an ignition timing based on the detected parameters. In an electronic control system of an engine in which the fuel injection amount and the ignition timing are controlled according to the control amount, it is determined whether or not the intake pressure is within a predetermined working range of the engine. Assuming that the signal line of the pressure sensor for detecting the intake pressure is disconnected or short-circuited, or that a failure such as the disconnection of the power supply line of the pressure sensor has occurred, the fuel supply amount, ignition timing, etc. Controlling according to the control amount obtained by the state parameter, storing pressure sensor failure information, turning on a warning light to notify the driver, Processing such as making a failure diagnosis device or the like easily understand a failure location is usually performed.

[Problems to be Solved by the Invention] In the above-described conventional control method for determining the failure of the pressure sensor, when the engine is running at a high speed and the accelerator pedal is fully closed, such as when descending the plate, the intake pressure becomes a very small value. As a result, it is difficult to distinguish between an output value at the time of a pressure sensor failure and a normal output value at the time of deceleration. Therefore, despite the normal operation of the pressure sensor, there is a problem in safety, such as determining that it is faulty and erroneously storing it as fault information, or turning on a warning light to make operators uneasy. I understood. This phenomenon is sometimes remarkable in the case of a pressure sensor used for a supercharged engine because the resolution is low.

The present invention has been made in order to solve the above-described problems, and can eliminate an erroneous determination of a failure of a pressure sensor, and does not perform a failure display due to an erroneous determination that gives anxiety to a driver. It is an object to provide a control method.

[MEANS FOR SOLVING THE PROBLEMS] An electronic control engine control method according to the present invention detects an throttle opening of an engine, and when the throttle opening is equal to or more than a predetermined value, an intake pressure downstream of the throttle valve detected by a pressure sensor. Is determined on the lower limit side in determining whether or not is within a predetermined range.

[Operation] In the present invention, the throttle opening is detected, and when the throttle opening is equal to or more than a predetermined value, the lower limit side determination as to whether or not the intake pressure downstream of the throttle valve detected by the pressure sensor is within a predetermined normal range. I do. If the detected intake pressure is out of the predetermined range, it is considered that some failure has occurred in the pressure sensor. In this case, control of the fuel supply amount, ignition timing, etc. based on the normal intake pressure and the engine speed is performed. Instead, engine control based on operating state parameters other than the intake pressure is performed.

FIG. 1 is a configuration diagram of an electronic control unit for an engine according to an embodiment of the present invention.

In this figure, 1 is an internal combustion engine, 2 is an intake pipe connected to the internal combustion engine 1, and 3 is a throttle valve provided in the intake pipe 2. A pressure sensor 4 is provided in the intake pipe 2 downstream of the throttle valve 3, and the pressure sensor 4 detects an intake pressure.

Then, the detection output is sent to the AD converter 91. The rotation of the internal combustion engine 1 is detected as a pulse by the rotation sensor 5, and the output of the rotation sensor 5 is sent to the input circuit 92. An injector 6 is provided in the intake pipe 2, and fuel is injected into the intake pipe 2 by the injector 6. The injector 6 is driven by the output of the output circuit 96 according to a command from the microprocessor 93. In addition, an ignition coil (not shown) is driven by an output of another output circuit 97 in response to a command from the microprocessor 93 to control ignition timing.

The throttle valve 3 is connected to a throttle opening sensor 8 for detecting the opening of the throttle valve 3. An output corresponding to the throttle opening is sent to the AD converter 91.

In FIG. 1, reference numeral 9 denotes a required fuel amount and ignition timing calculated based on information sent from the pressure sensor 4, the rotation sensor 5, the throttle opening sensor 8, and the like, and the drive pulse of the injector 6 and an ignition coil (not shown) is calculated. Fig. 3 shows a control device to be generated. The AD converter 91 in the control device 9 converts analog signals from the throttle opening sensor 8 and the pressure sensor 4 into digital values and sends them to the microprocessor 93. The input circuit 92 converts the level of the pulse output signal of the rotation sensor 5 and sends the output to the microprocessor 93. The microprocessor 93 calculates the amount of fuel to be supplied to the internal combustion engine 1 and the ignition timing based on the digital and pulse signals obtained from the AD converter 91 and the input circuit 92, and according to the calculation result, the injector 6 and the ignition coil (not shown). Output drive signal.

In the control device 9, the control procedure and data of the microprocessor 93 are stored in the ROM 94 in advance, and the data in the operation process is temporarily stored in the RAM 95. The output of the output circuit 96 drives the injector 6 in accordance with the output signal of the microprocessor 93, and the output of the output circuit 97 drives the ignition coil.

Next, the operation of the above embodiment will be described with reference to the flowchart of FIG.

First, in step 100, a throttle opening degree from the rotation sensor 5 is inputted from the signal or the engine speed N _e and the obtained intake pressure from the pressure sensor 4 (absolute pressure) value P _b and the throttle opening sensor 8 Read. And step 10
1, first, a determination value of the pressure sensor of whether the upper side is within a predetermined range, when the read intake air pressure value P _b is larger than the set upper limit value (e.g. 860MmHg) is normal engine operation Since the value is sometimes impossible, it is determined that the pressure sensor has failed, and the process proceeds to step 107 of the processing routine for the time of failure. Further, the process proceeds to the next step 102 when the intake pressure value P _b is smaller than the set upper limit value, the determination of whether it is determined the lower limit of the predetermined range of the pressure sensor, first, the condition of the throttle opening judge. That is, the throttle opening is compared with a predetermined value, for example, a value of about 5 degrees from the fully closed reference.
If the value is smaller than this value, the process proceeds to step 103; otherwise, the process proceeds to step 106.

In step 103, it is determined whether or not the rotation speed is higher than a predetermined value, for example, 3000 rpm. If the rotation is high, the process proceeds to step 104 to perform the process when the pressure sensor is normal, and if the rotation is low, the process proceeds to step 106. That is, in steps 102 and 103, the time of deceleration of the engine for which the failure determination of the pressure sensor is difficult is identified, and the lower limit of the predetermined range of the pressure sensor is not determined during the deceleration.

In step 106, to perform the determination the pressure sensor for the lower limit of whether the predetermined range, the intake pressure value P _b and setting a lower limit value, for example, by comparing the 100 mm Hg, when the pressure value P _b is larger to step 104 If not, the value is impossible to obtain except during high-speed deceleration.

In step 104, as a normal process when the pressure sensor is normal, the fuel amount and the ignition timing are determined based on the read intake pressure and engine speed, and in step 105, the fuel amount and the ignition timing are output to the injector and the ignition coil.

In step 107, in order to prevent malfunction due to noise or the like and reliably detect a failure, it is checked whether the state outside the predetermined range has continued for a certain time or a certain number of times,
If it has continued for a certain period or more, the process proceeds to step 108; otherwise, the process proceeds to the normal routine 104.

In step 108, the pressure sensor failure information is stored, and in the next step 109, a warning light for notifying the driver that the pressure sensor is faulty is lit, and further in the next step 11
At 0, the fuel amount and the ignition timing are determined from the throttle opening and the engine speed, and output to the injector and the ignition coil in step 105 as in the normal state of the pressure sensor.

By repeating the above operation, the failure determination of the pressure sensor is executed.

In the above embodiment, the throttle opening sensor is used to detect when the engine is decelerating. However, a switch that detects the throttle opening such that the output value of the pressure sensor at a high speed is equal to or higher than the failure determination identification level is used. It goes without saying that the same effect can be obtained even when used.

[Effects of the Invention] As described above, according to the present invention, the throttle opening is detected, and if the throttle opening is equal to or more than a predetermined value, whether the output value of the intake pressure sensor is within a predetermined range during normal operation of the engine. Is determined, the erroneous determination of the failure of the pressure sensor can be eliminated, and the engine control can be performed without performing the failure display due to the erroneous determination that gives anxiety to the driver.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electronic control unit according to one embodiment of the present invention, and FIG. 2 is a flowchart showing an operation of a control method of the present invention. In the figure, 1 is an engine, 2 is an intake pipe, 3 is a throttle valve, 4 is a pressure sensor, 5 is a rotation sensor, 6 is an injector, 8 is a throttle opening sensor, and 9 is a control device.

Claims (1)

(57) [Claims] An intake pressure is detected by a pressure sensor attached downstream of a throttle valve of an engine, an engine speed is detected, and a control amount such as a fuel supply amount and an ignition timing is determined based on the detected intake pressure and the engine speed. Is determined, and engine control is performed in accordance with the determined control amount, and it is determined whether the intake pressure is within a predetermined range. And determining the control amount on the basis of other operating state parameters, and controlling the engine according to the control amount. When the intake air pressure is equal to or greater than a predetermined value, a lower limit determination is performed in the determination as to whether or not the intake pressure is within a predetermined range. Law.