JPS60256533A - Electronic control fuel injector - Google Patents

Abstract

PURPOSE:To decide the idling condition reliably and to perform deceleration cut control accurately by providing means for deciding such condition where the output from a water temperature sensor is below predetermined level while the output from a throttle valve sensor or an injection pulse width is below predetermined level. CONSTITUTION:Under operation of car, the throttle opening TH and the water temperature Tw to be detected through a throttle sensor 20 and a water temperature sensor 46 are taken into a control circuit 54 to decide at first whether the water temperature Tw is below predetermined level T. If Tw<T, the throttle opening TH0 corresponding with the water temperature Tw is retrieved and compared with the actual opening TH and if TH0>TH, it is decided to be idling condition. If the rotation is higher than predetermined level, it is decided to be deceleration thus to perform fuel cut. While if Tw>=T, the operating condition of an idle switch in the throttle sensor 20 is decided to set an idle flug if it is turned on.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to an electronically controlled fuel injection device.

[Background of the invention]

Generally, electronically controlled fuel injection devices are disclosed in Japanese Patent Application Laid-Open No. 58-21773.
This is well known as stated in Publication No. 5.

By the way, this type of device uses an electric control valve to control the fast idle speed, but this is only used in luxury car specifications.

On the other hand, for Daesang car specifications, the fast idle speed is controlled by driving the throttle valve with wax because it is inexpensive and is used.

However, in this case, when driving at low temperatures with the wax activated and the throttle valve open, when deceleration is performed during so-called warm-up driving, the idle switch that operates to detect deceleration becomes inactive. Therefore, there was a problem that the fuel from the injector could not be cut.

[Purpose of the invention]

An object of the present invention is to reliably detect a deceleration state in a throttle valve control device using wax.

[Summary of the invention]

The feature of the present invention is that the wax is activated by detecting the water temperature signal.
In addition, when the throttle sensor output or the injector pulse width is less than a predetermined value, it is considered to be an idle state.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an intake pipe pressure type electronically controlled fuel injection device employing an electronically controlled fuel injection method for an internal combustion engine according to the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, this embodiment includes an air cleaner 12 for taking in outside air, and an intake air temperature sensor 1 for detecting the temperature of the intake air taken in by the air cleaner 12.
4, a throttle valve 18 for controlling the flow rate of intake air, which is disposed in the intake passage 16 and is opened and closed in conjunction with an accelerator pedal (not shown) disposed at the driver's seat; A throttle sensor 20 includes an idle switch for detecting whether the throttle valve 18 is at an idle opening and a potentiometer that generates a voltage output proportional to the opening of the throttle valve 18, and a throttle sensor 20 for preventing intake interference. A surge tank 22, an intake pipe pressure sensor 23 for detecting intake pipe pressure from the pressure inside the surge tank 22, a throttle lever 'l-248 interlocked with the throttle valve 18, and the unit. l-)LI L//<-
The throttle lever 24 is arranged in the manner of 24□□6.
Wax-filled idle rotation control valve 26 for controlling idle rotation speed by controlling the opening degree of the
, an injector 30 for injecting fuel located upstream of the gathering part of the intake manifold 28 and located upstream of the throttle valve, and an injector 30 for injecting fuel located upstream of the intake manifold 28 and an exhaust manifold 32 that determines the air-fuel ratio based on the residual oxygen concentration in the exhaust gas. a three-way catalytic converter 38 disposed in the middle of the exhaust pipe 36 on the downstream side of the exhaust manifold 32, and a distributor shaft that rotates in conjunction with the rotation of the crankshaft of the engine 10. Distributor 40 having
A top dead center sensor 42 and a crank angle sensor 44, which are built in the distributor 40 and output a top dead center signal and a crank angle signal, respectively, in accordance with the rotation of the distributor shaft, and a top dead center sensor 42 and a crank angle sensor 44, which are disposed in the engine block.
Cooling water temperature sensor 46 for detecting engine cooling water temperature
and.

The basic injection amount per engine stroke is calculated based on the intake pipe pressure output from the intake pipe pressure sensor 23 and the crank angle signal from the crank angle sensor 44. is the output of the throttle sensor 20, the air-fuel ratio of the output of the oxygen concentration sensor 34,
The fuel injection amount is determined by correcting the engine cooling water temperature output from the cooling water temperature sensor 46, and a valve opening time signal is output to the injector 30, and the ignition timing is adjusted according to the engine operating state. A digital control circuit 54 is provided for determining the igniter and outputting an ignition signal to the igniter-equipped coil 52 for control.

As shown in detail in FIG. 2, the digital control circuit 54 includes a central processing unit (hereinafter referred to as CPU) 60 consisting of a microprocessor that performs various calculation processes, and the intake temperature sensor 14. Potentiometer of throttle sensor 20, intake pipe pressure sensor 23, oxygen concentration sensor 34. An analog input port 2 with a multiplexer for converting analog signals input from the cooling water temperature sensor 46 etc. into digital signals and sequentially inputting them to the CPU 60, an idle switch of the throttle sensor 20, a top dead center sensor 42, and a crank angle. The digital signal input from the sensor 44 etc.
A digital input port 4 for inputting into the CPU 60 at a predetermined timing, a read-only memory (hereinafter referred to as ROM) 66 for storing programs or various constants, etc., and a read-only memory (hereinafter referred to as ROM) 66 for temporarily storing calculation data, etc. in the CPt 160. random access memory (hereinafter referred to as RA)
M) 68, a backup random access memory 70 which is supplied with power from an auxiliary power source and can retain memory even when the engine is stopped, and the calculation results of the CPU 60 are transferred to the injector 30.M at a predetermined timing. a digital output port door 2 for outputting to a coil 52 with an igniter, etc.;
It is composed of a common bus 74 that connects each of the above-mentioned component devices.

The operation of the above configuration will be explained with reference to FIG.

In step 80, first, the water temperature Tw and the throttle opening TH are taken in.

Next, in step 82, it is determined whether the water temperature is below a predetermined temperature.

If it is determined in step 82 that the value is less than the predetermined value, it indicates that the wax is in operation.

Next, in step 84, the throttle opening degree THO corresponding to the water temperature Tw is searched. This throttle opening degree T Ho has characteristics as shown in FIG. 4 depending on the water temperature.

Next, in step 86, the current throttle opening TH and the set throttle opening THo are compared, and if they are smaller, it is determined that the engine is in an idle state, and an IDLE flag is set in step 88.

When this flag is set, the engine is in an idling state, and if the number of rotations exceeds a predetermined value at this time, it is determined that the engine is decelerating and fuel is cut.

On the other hand, if the water temperature is equal to or higher than the predetermined value in step 82, step 9
0 indicates that the wax has stopped operating, and at this time the idle switch is activated, so the idle switch is determined in step 92, and if it is on, the IDLE flag is set, and if it is off, the IDLE flag is set. Clear.

Kai Nao, Yugap 84.86'? Although the water temperature and the throttle opening are set as TH, since the injection pulse width is also determined by the water temperature, this pulse width may be substituted for the throttle opening THo.

〔Effect of the invention〕

As described above, according to the present invention, since the idle state can be reliably determined, reliability can be maintained sufficiently even in cases such as deceleration cut.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an electronically controlled fuel injection system according to an embodiment of the present invention, Fig. 2 is a block diagram of a computer, Fig. 3 is a control flowchart, and Fig. 4 is a characteristic diagram of water temperature and throttle opening. be.

Claims (1)

[Claims] 1. In the electronically controlled fuel injection device, an idling state is detected by providing means for determining when the value of the water temperature sensor is below a predetermined value and the throttle sensor or the injection pulse width is below a predetermined value. Electronically controlled fuel injection system.