JPS59134336A - Method of controlling fuel injection of engine - Google Patents

Abstract

PURPOSE:To stabilize the condition of engine idling operation, by carrying out the increment of power even if the engine runs in its idling speed range when the temperature of engine cooling water is high. CONSTITUTION:Whether a water temperature 62 is turned on or off, that is, whether the temperature of engine cooling water reaches a predetermined temperature (for example, 110 deg. C) or not is judged. If it is judged as YES, a constant power increment value FPOWER is set as an increment value to calculate a fuel injection amount TAU. With this arrangement, the idling condition of the engine may be aimed at being stabilized even if the engine is restarted in a high temperature condition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection control method for an engine, and more specifically to an engine fuel injection method that increases the so-called power when the engine is in an idling state when the engine cooling water temperature is high. Regarding control method. In particular, power increase refers to correcting and increasing the fuel injection amount when it is desired to increase the engine output, that is, when the opening degree of the throttle valve or the engine speed exceeds a certain value.

In an engine equipped with a conventional electronic fuel injection control device, after restarting when the engine cooling water temperature is high, the air-fuel ratio becomes lean, which may cause a rough idle or a decrease in engine speed. This is caused by gasoline vapor generated within the delivery pipe of the fuel supply system.

SUMMARY OF THE INVENTION An object of the present invention is to provide an engine fuel injection control method that improves the stability of the idling state of the engine after a high-temperature restart.

The feature of the present invention is to input the detection outputs of various sensors that detect the operating state of the engine, calculate the amount of fuel injection to each cylinder of the engine by a control program stored in advance based on these detection outputs, In a device that controls the amount of fuel injection into each cylinder by driving the fuel injection valve provided in each cylinder based on the calculated value, when the engine is in an idling state when the engine cooling water temperature is high. The point is that it is configured to increase power.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of an engine to which the present invention is applied. In the figure, 1 indicates an engine. The engine 1 has a cylinder block 2 and a cylinder head 3. The cylinder block 2 receives a piston 4 in a cylinder pore formed inside the cylinder block 2. υ
, defines a combustion chamber 5 above the piston 4 in cooperation with the cylinder head.

The cylinder head 3 is formed with an intake boat 6 and a J71'fi hoard 7, and these boats are opened and closed by an intake valve 8 and an exhaust valve 9, respectively. Further, a spark plug 19 is attached to the cylinder head 3. The spark plug 19 is the ignition coil 26
A current generated by the combustion chamber 5 is supplied through the distributor 27, and sparks are generated by discharge in the combustion chamber 5.

An intake manifold 11, a surge tank 12, a throttle body 13, an intake tube 14, an air flow meter 15, and an air cleaner 16 are connected to the intake boat 6 in this order. The throttle body 13 is still in the engine intake system.
After that, install the intake tube 14 and the surge tank 1.
An air bypass passage 30 is provided to connect the air bypass passage 2 with the air bypass passage 30, and the opening/closing and opening degree of the air bypass passage 30 are controlled by an electromagnetic bypass flow control valve 31.

In addition, the exhaust boat 7 includes an exhaust manifold 17 and an exhaust pipe 1.
8 are connected in sequence.

A fuel injection valve 20 is attached near the connection end of the intake manifold 11 to each intake boat. Liquid fuel such as gasoline stored in a fuel tank 21 is supplied to the fuel injection valve 20 by a fuel pump 22 via a fuel supply pipe 23.

The throttle body 13 is provided with a throttle valve 24 for controlling the amount of intake nitrogen, and the throttle valve 24 is driven in response to depression of an accelerator pedal 25.

The air flow meter 15 detects the flow rate of air flowing through the engine intake system, and outputs a signal corresponding to the flow rate to the control device 50.

The IJ computer 27 has a built-in rotation speed sensor 29 that detects its rotation speed and rotation phase, in other words, the engine speed and crank angle, and this detection signal is input to the control device 50. It has become.

The controller 50 may be a microcomputer, an example of which is shown in FIG. It has a memory (RAM) 53, another random access memory (RAM) 54 that retains memory even after power is turned off, an A/D converter 55 having a multiplexer, and an I10 device 56 having a sofa. , these are common bus 57
are connected to each other by

The A/D converter 55 receives an air flow rate signal detected by the air flow meter 15, an intake temperature signal from the intake temperature sensor 58,
The water sensor 59 receives the water flooding signal, and the A/D converter 55 converts the data into A/D and outputs it to the CPU 51 and RAM 53 or 54 at a predetermined time according to instructions from the CPU 51. There is. Also, I10 device 56
The engine speed signal and crank angle signal outputted from the rotational speed sensor 29 and the nitrous fuel ratio signal outputted from the 02 sensor 60 are inputted to the input device 56, and the I10 device 56 processes these data according to instructions from the CPU 51. CPU5 at the time
1 and RAM 53 or 54.

The CPU 51 calculates the fuel injection amount based on the data detected by each sensor, and outputs a signal to the fuel injection valve 20 via the I10 device 56. The amount control is performed by combining the basic fuel amount determined by the air flow rate detected by the airflow meter 15 and the engine rotation speed detected by the rotation speed sensor 29 with the intake air temperature detected by the intake air temperature sensor 5.8. , water temperature sensor 59
The water temperature detected by 0. This is done by correcting the air-fuel ratio according to the air-fuel ratio detected by the sensor 60. In addition, 62 indicates that the engine cooling water temperature is a predetermined value (for example, 110°C).
The water temperature switch is turned on when the temperature reaches 1, and is used to determine whether or not the p1 engine is in a high temperature state.

Further, the CPU 51 outputs a bypass air amount signal to the bypass flow rate control valve 31 via the I10 device 56 in accordance with the intake temperature detected by the intake temperature sensor 58 and the water temperature detected by the water temperature sensor 59. It has become. The opening/closing and opening degree of the bypass flow rate control valve 31 are controlled in accordance with the bypass air amount signal given by the device 56.

The CPU 51 also generates an optimum ignition timing signal based on the basic fuel amount, the engine speed and crank angle outputted by the rotational speed sensor 29, and the intake air temperature detected by the intake air temperature sensor 58. The data is read from the ROM 52 and output from the I10 device 56 to the ignition coil 26.

Next, FIG. 3 shows the contents of the fuel injection control routine executed by the control device 50. In the figure, step 100
When the program is started, the basic fuel injection amount (basic fuel injection time) T is calculated in the next step 102. That is, the CPU 51 calculates the basic fuel injection time T based on the detection outputs of various sensors inputted via the A/D converter 55 and the I10 device 56. Here, the basic fuel injection time T is the fuel injection it set to an excess air ratio λ-1 (theoretical air-fuel ratio) based on the engine speed N and the intake air amount Q. Further, in step 104, it is determined whether the water temperature switch 62 is in the ON state, that is, whether the engine cooling water temperature has reached a predetermined value (for example, 110° C.). If the determination in step 104 is 'No', the power is increased by determining the trigger level based on the throttle opening degree TA, engine speed N, etc., which is carried out in the next step 106.

On the other hand, it is determined in step 104 that ly e, @ is the first
In other words, if it is determined that the engine cooling water temperature has reached a predetermined value, a constant power increase value F is determined in step 114.
POWER is set as an increase value, and in step 108, the fuel injection amount TAU is calculated using the following equation.

TAU=Tp・(1+FPO■R) Then, in the next step 110, the fuel injection amount TAU obtained in step 108 is set in the output register in the I10 device 56, and in step 112, the execution of the program is ended.

Next, FIG. 4 shows another embodiment of the fuel injection control routine. This embodiment differs from the embodiment shown in FIG. The other processing is exactly the same.

As explained above (in the present invention, the power is increased even when the engine cooling water temperature is high and the engine is in an idling state, so according to the present invention, even when the engine is restarted at a high temperature) The stability of the idling state can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an engine to which the present invention is applied, FIG. 2 is a block diagram showing a specific configuration of a control device 50, and FIG. 3 is a fuel injection executed by the control device 50. Flowchart showing the contents of the control routine, No. 4
The figure is a flowchart showing another embodiment of the fuel injection control routine. 15... Air flow meter, 20... Fuel injection valve, 2
9... Rotation speed sensor, 50... Control device, 58...
・Intake temperature sensor, 59...Water temperature sensor, 62 Kawamizubuchi switch. Agent: Tatsuyuki Unuma (and 2 others, Figure 2, Figure 3)

Claims (1)

[Claims] (Receives the detection outputs of various sensors that detect the operating state of the engine, and injects fuel into each cylinder of the engine based on these detection outputs according to a pre-stored control program. In a device that controls the amount of fuel injected into each cylinder by calculating the amount and driving the fuel injection valve provided in each cylinder based on the calculated value, when the engine cooling water temperature is high, the engine loses power. An engine fuel injection control method characterized by increasing power even outside the operating range. (2) A water temperature switch is used to determine whether the engine cooling water temperature is high or not, which operates when the engine cooling water temperature reaches a predetermined value. The fuel injection control method according to claim 1, characterized in that the determination is made based on whether the engine is in operation or not.(3) The determination as to whether the engine cooling water temperature is high A/ of the detection output of the water temperature sensor that detects the cooling water temperature
The fuel injection control method according to claim 1, characterized in that the determination is made based on the D conversion value.