JPH03189351A - Fuel injection system for internal combustion engine - Google Patents

Abstract

PURPOSE:To secure good drivability by estimating the extent of actual engine speed in use of rotational frequency at the driven side of a torque converter in an automatic transmission at time of something wrong in a crank angle sensor. CONSTITUTION:When trouble in a crank angle sensor is judged by a crank angle sensor trouble judging means, rotational frequency at the driven side of a torque converter is detected by an engine speed detecting means, thereby judging whether an automatic transmission is in a neutral range or not. If it is in the neutral range, an engine speed setting means sets the rotational frequency at the driven side of the torque converter as engine speed, and if the automatic transmission is a range other than the neutral one, the specified compensation is applied to the rotational frequency of the drive side of the torque converter, setting this speed as the engine speed. Using this setting engine speed, if a fuel injection quantity is operated, an almost proper mixture ratio is securable in consequence.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fuel injection device for an internal combustion engine, and more particularly to a countermeasure technique in the event of a failure of a crank angle sensor that detects engine rotational speed.

<Prior Art> The following are known as electronically controlled fuel injection devices for internal combustion engines.

That is, the intake air flow rate Q is determined in a control device based on a signal output from an intake air flow rate detection means such as a hot wire flow meter in response to the intake air flow rate Q, and the intake air flow rate Q is calculated based on the intake air flow rate Q and the crank angle sensor and ignition. The basic fuel injection amount Tp (=KXQ/N; K is a constant) is calculated by the control device from the engine rotational speed N calculated from the ignition signal from the coil, etc.

Then, various correction coefficients C0EF according to engine operating conditions such as engine cooling water temperature and correction numerator s based on battery voltage are used.
After calculating the final fuel injection amount Ti (=Tpx
COEF+Ts) is calculated.

Here, by outputting an injection pulse signal corresponding to the fuel injection amount Ti to the electromagnetic fuel injection valve, the fuel injection valve is driven to open and fuel injection is performed (JP-A-55-1
(See Publication No. 48295, etc.).

<Problems to be Solved by the Invention> By the way, in the above-described internal combustion engine, if the crank angle sensor fails, the engine rotation speed cannot be detected, and therefore the above-mentioned calculation of the fuel injection pulse becomes impossible.

For this reason, conventionally, when a crank angle sensor fails,
The engine rotation speed corresponds to ON and OFF of the idle switch respectively. OOOr, p, m and 300 Or, p, m
The above-mentioned fuel injection pulse is calculated based on this provisional engine speed.

However, as is clear from the characteristic diagram shown in Figure 9, there is a difference between the provisionally set engine rotation speed and the actual engine rotation speed, so the mixture ratio may become leaner or richer in the shaded areas in the diagram. This resulted in poor drivability.

In view of the above-mentioned conventional problems, the present invention estimates the engine rotation speed using the rotation speed of the driven side of the torque converter of the automatic transmission when the crank angle sensor fails. The purpose is to improve drivability by using a configuration that executes fuel injection using engine rotational speed.

<Means for Solving the Problems> For this reason, the fuel injection device for an internal combustion engine of the present invention, as shown in FIG. 1, sets the fuel injection amount based on the engine intake air flow rate and the engine rotation speed, In a fuel injection device for an internal combustion engine that drives and controls a fuel injection valve based on a set fuel injection amount, a crank angle sensor failure determination means determines whether or not there is a failure in a crank angle sensor that detects the engine rotational speed. a rotational speed detection means for detecting a rotational speed of a driven side of a torque converter of an automatic transmission; and a detection by the rotational speed detection means that the automatic transmission is in a neutral range when a failure is determined by the determination means. an engine rotation speed setting means for setting the rotation speed as the engine rotation speed, and applying a predetermined correction to the rotation speed detected by the rotation speed detection means in a range other than neutral of the automatic transmission, and setting the rotation speed as the engine rotation speed; It was configured with

<Operation> In this configuration, when a failure of the crank angle sensor is determined, the rotation speed of the driven side of the torque converter is detected by the rotation speed detection means, and it is determined whether the automatic transmission is in the neutral range.

If it is in the neutral range, the rotational speed of the driven side of the torque converter is set as the engine rotational speed.

If the automatic transmission is determined to be outside the neutral range,
A predetermined correction is made to the rotational speed of the driven side of the torque converter, and this is set as the engine rotational speed.

As described above, when the crank angle sensor fails, the actual rotational speed of the engine can be estimated by using the rotational speed of the driven side of the torque converter of the automatic transmission, and this estimated value can be used to By calculating the amount, a substantially appropriate mixture ratio can be obtained, and good drivability can be ensured.

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

FIG. 2 is a diagram showing an embodiment of the present invention, in particular, a control unit 15 for engine control that controls the operation of the engine.
and a control unit 21 for transmission control that controls the speed change operation of the automatic transmission are provided independently so as to be able to communicate with each other. II control unit 1-21 to engine control control unit 15
FIG. 2 is a control system diagram of a configuration in which a control unit 15 for engine control controls the operation of the engine based on an engine control request signal outputted to the engine control request signal.

That is, in the figure, air is taken into a main body 11 of an internal combustion engine (hereinafter referred to as the engine) from an air cleaner (not shown) through a throttle valve 12 that is linked to an accelerator, and further through an intake manifold 13.

A fuel injection valve (injector) 14 is provided in a branch portion of the intake manifold 13 for each cylinder. Each fuel injection valve 14 is an electromagnetic fuel injection valve that opens when a solenoid is energized and then stops when the energization is stopped to open the valve. Fuel that is pressure-fed from the pump and adjusted to a predetermined pressure by a pressure regulator is injected and supplied to the engine body 11.

As shown in FIG. 3, the control unit 15 for engine control receives output signals from various sensors, and receives output signals from built-in l1022. CPU23. The memory 24 performs arithmetic processing to determine the fuel injection amount (injection time) Ti and injection timing (injection method), and in accordance with these, a drive pulse signal is sent to the fuel injection valve 14 via the drive circuit 28 of the fuel injection valve 14.
Output to.

As the various sensors, an air flow meter 16 as an intake air amount sensor is provided upstream of the throttle valve 12, and outputs a signal corresponding to the intake air amount Q. Further, a crank angle sensor 17 is provided in the distributor (not shown) and outputs a reference signal every 120 degrees. Here, the rotational speed N of the engine can be detected by measuring the period of the reference signal.

Further, the throttle valve 12 is provided with a potentiometer-type throttle sensor 18, which outputs a signal corresponding to the opening degree α of the throttle valve 12. Furthermore, the engine body 11
A water temperature sensor 19 is provided in the water jacket, and outputs a signal corresponding to the cooling water temperature Tw. Further, the voltage of a battery 20 is applied to the control unit 15 as its operating power source and for detecting the power supply voltage VB.

The fourth fuel injection setting routine is executed by the microcomputer in the control unit 15 for engine control.
This will be explained based on the flowchart shown in the figure.

That is, in step (hereinafter abbreviated as S as in the figure) 1, information on the engine operating state detected by each sensor is input.

In S2, a basic fuel injection amount Tp (=KXQ/N; is a constant) is calculated based on the intake air flow rate Q and the engine rotational speed N.

In S3, various correction coefficients C0EF are set based on the cooling water temperature Tw, etc., which represent the engine temperature.

In S4, a voltage correction numerator s is set based on the voltage VB of the battery 20. This voltage correction numerator s is for correcting a change in the effective opening time of the fuel injection valve 14 due to a change in the battery voltage VB.

In S5, the actual fuel injection amount is calculated using the following equation using the obtained Tp, COEF, and Ts.

Ti = Tp Arithmetic processing is performed by the CPU 26 and the memory 27, etc., and the shift solenoid is controlled via the shift solenoid drive circuit 29, thereby executing speed change control.

As one of the various sensors, a turbine rotation sensor 30 is provided as rotation speed detection means for detecting the rotation speed of the driven side of the torque converter of the automatic transmission.

As described above, this system has a configuration in which the engine control control unit 15 controls engine operation based on an engine control request signal output from the automatic transmission control control unit 21 to the engine control control unit 15. Each control unit 15°21 is equipped with communication ICs 31 and 32.

Here, the control unit 15 includes a crank angle sensor failure determination means for determining whether or not there is a failure in the crank angle sensor, and when the failure is determined by the determination means, the automatic transmission is in the neutral range and the turbine The engine rotation is set as the engine rotation speed by setting the rotation speed detected by the rotation sensor 3o as the engine rotation speed, and applying a predetermined correction to the rotation speed detected by the turbine rotation sensor 30 when the automatic transmission is in a range other than neutral. A speed setting means is provided.

Note that the control unit 15 receives a detection signal from the neutral switch 33 of the automatic transmission.

The operation of each of the above means will be explained based on the flowchart of FIG.

In Sll, it is determined whether the crank angle sensor 17 is out of order, and if it is determined to be normal, the process proceeds to S12, and if it is determined to be abnormal, the process proceeds to 313.

In S12, the engine rotational speed Ne is calculated based on the signal output from the crank angle sensor 17, the process proceeds to S14, the intake air amount Q is calculated, and the process proceeds to S15, where the above-mentioned injection pulse width Ti is calculated as described above. Calculate according to the formula.

On the other hand, in S13, the turbine rotation speed is detected by the turbine rotation sensor 33, and the process proceeds to S16, where it is determined whether the automatic transmission is in the neutral range. If it is in the neutral range, the process proceeds to S17, where the turbine rotational speed Nt is set as the engine rotational speed Ne, and the process proceeds to S14, and then to S15. If it is determined in S16 that the automatic transmission is outside the neutral range, the process proceeds to 31B, where a predetermined correction described later is applied to the turbine rotational speed Nt, and this is set as the engine rotational speed Ne, and the process proceeds to S14. , 315.

Here, the failure determination of the above-mentioned crank angle sensor is performed using ref
A failure is determined when at least one of the signal and the POS signal is abnormal.

Next, a predetermined calculation method applied to the turbine rotational speed rl in step 319 described above will be explained.

First, engine rotation speed Ne, engine output torque Te
, turbine rotational speed Nt, and turbine output can be calculated from data for each engine as shown in the turbine output diagram.

The above Tt is Tt=tXrXNe2, and the torque ratio t and the input capacity coefficient τ can be calculated from data for each torque converter as shown in FIG.

For example, the torque ratio t and the input capacity coefficient τ are Nt/
Assuming that N e =α, set tα and τα.

Therefore, the engine rotational speed Ne can be calculated as follows: Ne''=Nt''·Te/Tt=Nt''.

According to this configuration, when the crank angle sensor fails,
By using the turbine rotation speed, in the neutral range, D
By applying a predetermined calculation to the turbine rotation speed in a range other than the neutral range such as a range, a value close to the actual rotation speed of the engine can be obtained (see FIG. 8). Therefore, if the fuel injection amount is calculated using this value, a substantially appropriate mixture ratio can be obtained, and good drivability can be ensured.

<Effects of the Invention> As explained above, according to the present invention, when the crank angle sensor fails, the actual rotational speed of the engine can be estimated by using the rotational speed of the driven side of the torque converter of the automatic transmission. If this estimated value is used to calculate the fuel injection amount, a substantially appropriate mixture ratio can be obtained, which is extremely useful in ensuring good drivability. .

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to claims of the present invention, Fig. 2 is a system diagram showing an embodiment of the present invention, Fig. 3 is a diagram showing the configuration of a control unit in the same embodiment, Figs.
6 is a characteristic diagram of engine output torque, FIG. 7 is a characteristic diagram of torque ratio and input capacity coefficient, and FIG. 8 is a characteristic diagram showing detailed explanations of the present invention. 9 are characteristic diagrams illustrating the conventional drawbacks. 11... Engine body 14... Fuel injection valve 15
...Engine control control unit 17...
Crank angle sensor 18... Throttle sensor 1 9... Water temperature sensor 1... Automatic transmission control unit rotation sensor 30... Turbine

Claims (1)

[Claims] In a fuel injection device for an internal combustion engine, a fuel injection amount is set based on an engine intake air flow rate and an engine rotational speed, and a fuel injection valve is driven and controlled based on the set fuel injection amount. a crank angle sensor failure determining means for determining the presence or absence of a failure of a crank angle sensor that detects a failure; a rotational speed detecting means for detecting a rotational speed of a driven side of a torque converter of an automatic transmission; When the automatic transmission is in a neutral range, the rotational speed detected by the rotational speed detection means is set as the engine rotational speed, and the automatic transmission is in a range other than neutral, and the rotational speed detected by the rotational speed detection means is set as the engine rotational speed. 1. A fuel injection device for an internal combustion engine, comprising: an engine rotation speed setting means for setting an engine rotation speed after applying a predetermined correction.