JPH0596448U - Electronically controlled fuel injection device - Google Patents

Abstract

(57) [Summary] [Purpose] To smooth the torque fluctuation of the engine when the vehicle shifts from decelerating to steady driving. [Structure] In the deceleration traveling mode, fuel control is performed completely independently of the fuel control in the steady traveling mode. When returning from the deceleration running mode to the steady running mode again, a predetermined correction is made to the fuel injection amount control in the steady running mode. That is, the post-deceleration travel correction coefficient CACOR calculated immediately before the shift based on the engine speed N in the deceleration travel mode is multiplied by the atmospheric pressure correction coefficient CACOP, and the corrected post-deceleration travel correction coefficient CACO is corrected. Basic pulse width PW
It is multiplied by B to determine the output pulse width PW. The post-deceleration travel correction coefficient CACO is gradually amplified or attenuated for each fuel injection so that its value becomes 1.0 after a lapse of a predetermined time from the travel mode transition.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electronically controlled fuel injection device that supplies fuel to an engine mounted on a vehicle.

[0002]

[Prior Art]

 Generally, in an electronically controlled fuel injection device for an engine mounted on a vehicle, the vehicle is decelerated while the drive wheels of the vehicle and the engine are connected, that is, the clutch for the purpose of improving fuel efficiency and purifying exhaust gas. Fuel is being cut during deceleration when the vehicle is decelerated while the throttle valve is connected and the throttle valve is fully closed (that is, the idle opening). Conventionally, as an electronically controlled fuel injection device that performs fuel cut during deceleration, if the throttle valve fully closed duration is longer than a certain time, and the engine speed at that time is higher than the predetermined fuel cut speed, When the fuel cut is started and then the engine speed falls below a predetermined fuel return speed, there is a method in which the fuel cut is stopped and the fuel is injected again (see Japanese Patent Laid-Open No. 60-125747).

[0003]

[Problems to be solved by the device]

 In the conventional electronically controlled fuel injection device described above, when the vehicle is in the decelerating traveling state and fuel cut is started, the torque generated by the engine rapidly changes. Also, when fuel is injected again from the fuel cut state, a rapid torque fluctuation occurs. It is conceivable that fuel will not be cut off during deceleration driving and fuel injection will continue, but even then, when the vehicle returns from deceleration driving to steady driving, a sudden torque fluctuation may occur. An object of the present invention is to provide an electronically controlled fuel injection device capable of smoothing torque fluctuation of an engine when a vehicle shifts from decelerating traveling to steady traveling.

[0004]

[Means for Solving the Problems]

 The electronically controlled fuel injection device according to the present invention controls the fuel injection by the fuel injection valve based on the detection of the fuel injection valve, the detection means for detecting the operating state of the engine mounted on the vehicle, and the detection means. The control means controls the fuel injection amount at the time of decelerating traveling of the vehicle in a state where the drive wheels of the vehicle and the engine are connected, completely independently of the steady traveling, and When the vehicle returns to the steady running from the deceleration running again, the fuel injection amount control during the steady running is subjected to a predetermined correction.

[0005]

【Example】

 The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a schematic diagram showing a control system of an engine to which an electronically controlled fuel injection device according to an embodiment of the present invention is applied. In this figure, an electronic control unit (ECU) 10 obtains an output pulse width PW based on an engine speed N, a throttle opening THP, an atmospheric pressure PRS, a water temperature WT, and other various sensor information 20, and the output pulse width PW Based on the above, the valve opening time of the fuel injection valve 11 is controlled to inject a required amount of fuel into the intake manifold 12. The fuel injected from the fuel injection valve 11 is sucked into the cylinder 14 together with the air sucked through the air cleaner 13, and after combustion, is discharged as exhaust gas from the exhaust manifold 15 to the atmosphere via a catalytic converter, a muffler and the like (not shown). Is released.

Of the information on the operating state of the engine sent to the electronic control unit 10, the engine speed N is calculated from the ignition pulse P sent from the ignition unit 16. The throttle opening THP is detected by a throttle opening sensor 17 provided near the throttle valve 21. The atmospheric pressure PRS is detected by the atmospheric pressure sensor 18. The water temperature WT is detected by a water temperature sensor 19 provided near the cooling water passage (not shown).

The operation of this embodiment will be described with reference to FIGS. When the throttle valve 21 is not fully closed, the electronic control unit 10 enters the steady running mode (FIG. 2). In the steady running mode, the valve opening time of the fuel injection valve 11 is controlled based on the output pulse width PW, and a required amount of fuel is injected. The output pulse width PW is determined by performing a predetermined correction on the basic pulse width PWB, as shown in FIG.

The basic pulse width PWB is corrected by unit correction coefficient CPW, volumetric efficiency correction coefficient CVE, air-fuel ratio (A / F) correction coefficient CAF, reference highland correction coefficient CPRSR multiplied by atmospheric pressure correction coefficient XALT. This is performed by multiplying the basic pulse width PWB by the coefficient CPRS, the intake air temperature correction coefficient CAT, and the post-deceleration correction coefficient CACOR. The unit correction coefficient CPW, the volumetric efficiency correction coefficient CVE, the air-fuel ratio correction coefficient CAF, and the reference highland correction coefficient CPRSR are the engine load coefficient XPRS and the engine speed N calculated from the throttle opening THP and the engine speed N, respectively. Required based on. The post-deceleration traveling correction coefficient CACOR is set to an initial value of 1.0, and does not affect the basic pulse width PWB in the steady traveling mode in which the deceleration traveling mode has never been entered.

When the throttle valve 21 is fully closed and the engine speed N at this time is higher than a predetermined high rotation side determination rotation speed N1, or the engine rotation speed N is higher than the high rotation side determination rotation speed N1. The electronic control unit 10 enters the deceleration mode when a certain time has elapsed since the temperature became low (FIG. 2). In the deceleration traveling mode, the electronic control unit 10 performs fuel control completely independent of the fuel control in the steady traveling mode. In other words, in the deceleration running mode, as shown in FIG. 4, the deceleration running pulse width PWCO AS corresponding to the engine speed N is calculated, independently of the determination of the output pulse width P W in the steady running mode. The output pulse width PW is determined by multiplying the deceleration travel pulse width PWCOAS by the atmospheric pressure correction coefficient COPRS and then adding the invalid pulse width Tv. Then, the valve opening time of the fuel injection valve 11 is controlled on the basis of the output pulse width PW to inject a required amount of fuel. In this deceleration traveling mode, as shown in FIG. 5, the post-deceleration traveling correction coefficient CACOR is calculated based on the engine speed N, and the value is constantly updated during the deceleration traveling mode.

When the throttle valve 21 is opened, the vehicle speed decreases and the engine speed N becomes lower than the high speed side determination speed N1 and a certain time has elapsed or the engine speed N When N becomes lower than the predetermined low rotation side determination rotation speed N2, the electronic control unit 10 exits the deceleration running mode and returns to the steady running mode again (FIG. 2). In the electronic control unit 10 that has shifted from the deceleration traveling mode to the steady traveling mode, as shown in FIG. 3, the post-deceleration traveling correction coefficient CACOR calculated immediately before the transition in the deceleration traveling mode is multiplied by the atmospheric pressure correction coefficient CACOP. .. The corrected post-deceleration correction coefficient CACO is multiplied by the corrected basic pulse width PWB, and the invalid pulse width Tv is added to determine the output pulse width PW. As shown in FIG. 6, the correction coefficient CACOR after deceleration traveling is gradually amplified or attenuated (tailed) at each fuel injection so that the value becomes 1.0 after a predetermined time has elapsed from the transition to the traveling mode.

FIG. 7 is a flowchart for selecting a driving mode in the electronic control unit 10.

The process of selecting the traveling mode will be described with reference to this figure. In step S1, it is determined whether or not the throttle valve 21 is fully closed. In step S1, if the throttle valve 21 is not in the fully closed state, the process proceeds to step S2 to enter the steady running mode, and if the throttle valve 21 is in the fully closed state, the process proceeds to step S3.

In step S3, it is determined whether the engine speed N is higher than a predetermined high speed side determination speed N1. In step S3, when the engine speed N is higher than the high speed side determination speed N1, the process proceeds to step S4 to enter the deceleration running mode, and the engine speed N is lower than the high speed side determination speed N1. If so, proceed to step S5.

In step S5, it is determined whether the engine rotation speed N is lower than a predetermined low rotation side determination rotation speed N2. In step S5, when the engine speed N is lower than the low speed side determination speed N2, the process proceeds to step S2 to enter the steady running mode, and when the engine speed N is higher than the low speed side determination speed N2. Then proceed to step S6.

In step S6, it is determined whether or not a predetermined time has elapsed since the engine speed N became lower than the high speed side determination speed N1. In step S6, if the fixed time has elapsed, the process proceeds to step S2 to enter the steady traveling mode, and if the constant time has not elapsed, the process proceeds to step S4 to enter the deceleration traveling mode. After that, the determination is repeated in the same manner as described above.

As described above, according to the above-described embodiment, when the vehicle is decelerated while the engine and the drive wheels are coupled, that is, when the vehicle is decelerated while the engine is being braked, the fuel cut is performed. The fuel injection amount is set independently of the steady-state running and the air-fuel ratio control is performed without performing the operation, and it is possible to suppress a sudden torque fluctuation of the engine during decelerating running, which results in vehicle stability. Etc. can be improved. Further, when the vehicle returns from the decelerated traveling to the steady traveling again, a predetermined post-decelerated traveling correction is performed, that is, the electronic control unit calculates the post-decelerated traveling correction coefficient CACOR calculated immediately before the transition in the decelerated traveling mode, Since the output pulse width PW is determined by multiplying the corrected basic pulse width PWB, it is possible to smooth the engine torque fluctuation when shifting from deceleration running to steady running.

In the above embodiment, the throttle valve 21 is in the fully closed state, the engine speed N is higher than a predetermined high speed side determination speed N1, or the engine speed N is high speed side determination. The condition in which the electronic control unit 10 enters the deceleration traveling mode is that a certain period of time has elapsed since the engine speed became higher than the rotation speed N1. In addition to these, the warm-up operation of the engine is completed, that is, the water temperature. The condition may be that the water temperature WT detected by the sensor 19 has reached a specified value.

[0018]

[Effect of the device]

 As described above, according to the present invention, it is possible to smooth the torque fluctuation of the engine when the vehicle shifts from decelerating traveling to steady traveling.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a control system of an engine to which an electronically controlled fuel injection device according to an embodiment of the present invention is applied.

FIG. 2 is a diagram for explaining determination of a decelerated traveling state.

FIG. 3 is a diagram for explaining pulse width calculation in a steady running mode in the electronic control unit.

FIG. 4 is a diagram for explaining pulse width calculation in a deceleration traveling mode in the electronic control unit.

FIG. 5 is a diagram showing a relationship between a correction coefficient CACOR after deceleration traveling and an engine speed N.

FIG. 6 is a diagram showing a relationship between a post-deceleration correction coefficient CACOR and the number of fuel injections.

FIG. 7 is a flowchart for selecting a driving mode in the electronic control unit.

[Explanation of symbols]

 10 Electronic Control Unit (Control Means) 17 Throttle Opening Sensor (Detection Means) 18 Atmospheric Pressure Sensor (Detection Means) 19 Water Temperature Sensor (Detection Means) P Ignition Pulse

Claims (1)

[Scope of utility model registration request] 1. A control means comprising a fuel injection valve, a detection means for detecting an operating state of an engine mounted on a vehicle, and a control means for controlling fuel injection by the fuel injection valve based on the detection of the detection means. Controls the fuel injection amount completely independently of the steady running when the vehicle is decelerating while the drive wheels of the vehicle and the engine are connected, and the vehicle returns from the slow running to the steady running again. In this case, the electronically controlled fuel injection device is characterized in that the fuel injection amount control during steady running is subjected to a predetermined correction.