JPS5999050A - Control device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To increase practical utility by a method wherein an economical mode, excellent in the performance of fuel consumption, and the mode of output, excellent in the performance of output, can be selected in accordance with the preference of a driver or the operating condition of the engine. CONSTITUTION:When the driver switches a mode selecting switch 48 from the output mode into the economical mode, an idle-up releasing solenoid valve 24 is put ON throuth an ECU 50 when a cooling water temperature, detected by a water temperature sensor 46, is higher than a predetermined value and a vacuum, detected by a vacuum switch 36, is higher than a predetermined value, or when a revolving speed, detected by a revolution sensor 45, is at the side of low revolution. At the same time, an EGR controlling switching valve 34 is operated, atmosphere is introduced into the vacuum chamber 30a of the EGR valve 30 and the EGR is cut off. Further, in case a throttle switch 25 is put ON, ignition timing is controlled to advance side through an ignition timing control circuit 38 while the conduction of a solenoid valve 16 for slow cut is released in case the engine is brought into a deceleration condition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an internal combustion engine, and is particularly suitable for use in an automobile engine with exhaust gas purification measures. This invention relates to an improvement of a control device for an internal combustion engine that controls the air-fuel ratio, ignition timing, etc. based on the above.

Internal combustion engines, especially automobile engines with exhaust gas purification measures, require strict control of the air-fuel ratio. When an air-fuel ratio feedback condition is established using an oxygen concentration sensor to detect the air-fuel ratio and an air-fuel ratio control means to control the air-fuel ratio of the air-fuel mixture, the exhaust air-fuel ratio detected by the oxygen concentration sensor and the target air-fuel ratio are An air-fuel ratio control method for an internal combustion engine has been put into practical use, in which the air-fuel ratio of the air-fuel mixture is feedback-controlled according to the deviation from the air-fuel mixture.

Additionally, in general, in spark-ignition internal combustion engines such as gasoline engines, controlling the ignition timing to an appropriate value that matches the operating conditions of the engine improves the output performance and fuel efficiency of the internal combustion engine. This is extremely important. Various ignition timing control methods have been put into practical use for such internal combustion engines, but in recent years, electronic ignition timing control devices have been used to control standard values determined from engine load and engine speed. An ignition timing control method for an internal combustion engine has been proposed that controls the ignition timing according to the ignition timing.

Furthermore, as a combination of air-fuel ratio control and ignition timing control as described above, internal combustion engine control is performed in which the air-fuel ratio and ignition timing are controlled based on output signals from sensors installed in various parts of the engine. The device has been put into practical use.

On the other hand, in both the air-fuel ratio control and ignition timing control, among the various performances of the vehicle equipped with the engine,
The optimal adaptive value differs depending on whether emphasis is placed on fuel efficiency or output performance. Therefore, in the past, so-called economy cars, which placed emphasis on fuel efficiency, and so-called high-performance cars, which placed emphasis on output performance, were made with different specifications, and it was difficult to achieve both in a single vehicle.

On the other hand, in order to achieve the same objective as the present invention, in a vehicle equipped with an electronically controlled automatic combustion engine, so-called economy shift, which emphasizes fuel efficiency, and so-called power shift, which emphasizes output performance, are selected. Although some systems that have made this possible have been put into practical use, it has not been possible to change the air-fuel ratio, and the effects have not always been sufficient.

Also, so-called variable cylinder number engines have been put into practical use, in which all cylinders are activated when high output is required, while some cylinders are deactivated when high output is not required, but production costs are low. The problem was that it took a long time.

The present invention has been made to solve the above-mentioned conventional problems.With the same engine, there is an economic mode that emphasizes fuel efficiency and an economy mode that emphasizes output performance, without impairing exhaust gas purification performance and drivability. The output mode can be freely selected depending on the driver's preference or usage conditions.
Moreover, it is an object of the present invention to provide a control device for an internal combustion engine that is inexpensive to produce.

The present invention provides a control device for an internal combustion engine that controls the air-fuel ratio, ignition timing, etc. based on output signals from sensors disposed in various parts of the engine, in which an economy mode or an output mode is selected. A selection switch is provided, and when the economy mode is selected by the mode selection switch, at least the air-fuel ratio in the normal operating state is set to the side of the stoichiometric air-fuel ratio, and the ignition timing is set to the side of the standard value. On the other hand, when the output mode is selected, at least the air-fuel ratio in the normal operating state is set near the stoichiometric air-fuel ratio, and the ignition timing is set to the standard value, thereby achieving the above objectives.

Further, when the economy mode is selected by the mode selection switch, exhaust gas recirculation and idle up are not performed, thereby further improving drivability and fuel efficiency.

Alternatively, when the multi-output mode is selected by the mode selection switch, the fuel cut range during deceleration is narrowed to improve drivability during re-acceleration.

As shown in FIG. 1, the present invention employs exhaust gas recirculation (hereinafter referred to as EGR) since the amount of nitrogen oxides, which are harmful components in exhaust gas, are emitted in a small amount when the air-fuel ratio is around 20. Therefore, when using it as an economy car, the air-fuel ratio of the mixture entering the combustion chamber should be set to the lean side with less nitrogen oxides, and the ignition timing should be moved to the advanced side accordingly. On the other hand, when using it as a high-performance vehicle, it is sufficient to set the air-fuel ratio to the optimum air-fuel ratio near the stoichiometric air-fuel ratio (14,5) and perform EG and R to suppress nitrogen oxides. In addition, in consideration of drivability, it is also possible to change the presence or absence of idle up when a load is applied and the fuel cut range during deceleration depending on each mode.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an automobile engine control device employing an internal combustion engine control device according to the present invention will be described in detail with reference to the drawings.

In this embodiment, as shown in FIG. A venturi type carburetor 14, a slow cut solenoid valve 16 which is opened when energized to bleed a large amount of air to the slow system of the carburetor 14 and cut off slow fuel, and a slow cut solenoid valve 16 which is opened when energized to cut off slow fuel. A lean bleed switching valve 18 performs air bleed into the fuel passage of the capretor 14 to make the air-fuel ratio of the air-fuel mixture formed in the capretor 14 closer to the stoichiometric air-fuel ratio.
, a throttle valve 20 that is configured to rotate in conjunction with an accelerator pedal (not shown) disposed on the driver's seat for controlling the flow rate of the air-fuel mixture; A tarspot 22 that opens to a predetermined opening degree, and a solenoid valve 2 for canceling idle up that supplies intake pipe negative pressure to the negative pressure chamber 22m of the dart pot 22 when energized to cancel idle up.
4, a throttle switch 25 that outputs a 111 signal when the throttle valve 20 is opened and in an off-idle state, and a part of the exhaust gas recirculated to the intake manifold 28 via the exhaust passage 26 to perform EGR. an exhaust gas recirculation amount control valve (hereinafter referred to as EGR valve) 30;
an EGR control modulator 32 for forming a control negative pressure introduced into the negative pressure chamber 30a of the EGR valve 30; a negative pressure switch 36 that outputs a 111 signal when the negative pressure in the intake manifold 28 reaches a predetermined value or higher; and an ignition timing control circuit 38. An igniter 40 that generates a primary ignition signal according to the output, and the igniter 4
A direct ignition coil 42 for converting a 0 output primary ignition signal into a high voltage secondary ignition signal, and a spark plug disposed in each cylinder of the engine 10 to convert the ignition secondary signal generated by the ignition coil 42 into a high voltage secondary ignition signal. (not shown), which is equipped with a negative pressure advance device 44a, and an engine rotation sensor 4 for detecting the rotational speed of the engine 100.
5, a water temperature sensor 46 for sensing the engine cooling water temperature, which is self-filmed on the cylinder block (not shown) of the engine 10, and an economic mode (hereinafter E) that emphasizes fuel efficiency.
A mode selection switch 48 that outputs a "1" signal when the E mode is selected, which is used to select an output mode emphasizing output performance (hereinafter referred to as P mode); When the E mode is selected by the switch 48, the air-fuel ratio in the normal operating state is set to the higher side than the stoichiometric air-fuel ratio, the ignition timing is set to the higher side than the standard value, and EGR and idle up are not performed. On the other hand, when the P mode is selected, the electronic control unit controls the air-fuel ratio in normal operating conditions to be near the theoretical Ml-nitrogen fuel ratio, sets the ignition timing to the standard value, and prevents fuel cut during deceleration. (hereinafter referred to as ECU) 50.

As shown in detail in FIG. 3, the ECU 3O includes a first comparator 52 that outputs a 11" signal when the engine cooling water temperature is higher than a predetermined value, according to the output of the water temperature sensor 46. , according to the output of the engine rotation sensor 45, the second comparator 54 outputs an 11'' signal at low rotation when the engine rotation speed is less than or equal to the first predetermined value. The third comparator 56 outputs the II'' signal when the engine speed is higher than a predetermined value, and outputs the 11w signal when the engine speed is lower than a third predetermined value, which is different from the first predetermined value. A first AND that outputs the logical product of the fourth comparator 58 and the outputs of the comparators 52, 54, the mode selection switch 48, and the negative pressure switch 36 to the idle-up release solenoid valve 24, etc.
a first OR circuit 6 that outputs the logical sum of the outputs of the third comparator 56 and the throttle switch 25;
2, a first inverter 64 that inverts the output of the first comparator 52, and the logical sum of the outputs of the first inverter 64 and the first AND circuit 60, and the EGR control switching valve 34. a second OR circuit 66 that outputs an output to the first (
A second AND circuit 68 that outputs the logical product of the outputs of the DAND circuit 6o and the first +7) OR circuit 62 to the lean bleed switching valve 18 and the ignition timing control circuit 38, and the output of the 51st AND circuit 60. a second inverter 7o that inverts the output of
circuit 72.

The action will be explained below.

When the driver switches the mode selection switch 48 to E mode, the output signal of the mode selection switch 48 is 11.
Therefore, the engine cooling water temperature is higher than the predetermined value, the intake pipe negative pressure is higher negative pressure (light load) than the predetermined value, and the engine rotation speed is lower than the first predetermined value. side, the output of the first AND circuit 6o is f1''
Then, the idle-up release solenoid valve 24 is turned on, the idle-up is released, and the idle rotation speed is set to E.
Low rotation for mode.

Also, when the output of the first AND circuit 6o or the output of the first inverter 64 is key 11, that is, when the engine cooling water temperature is higher than the predetermined value, the E mode is selected. When the load is light and the rotation speed is low, or when the engine cooling water temperature is lower than a predetermined value, the first O
The output of the R circuit 66 becomes Ill, the EGR control switching valve 34 operates, the atmosphere is introduced into the negative pressure chamber 30a of the EGR valve 30, and EGR is cut off.

Furthermore, when the output of the first AND circuit 6o is 111 and the output of the second OR circuit 62 is 11#, that is, when the engine coolant temperature is on the high temperature side, the mode selection switch is 48, the E mode is selected, the intake pipe negative pressure is on the high negative pressure side, and the engine rotation speed is lower than the first predetermined value. When the value is higher than the second predetermined value or when the throttle switch 25 is on, the second AND circuit 6
When the output of 8 becomes 111, the lean bleed switching valve 18 is activated to bleed air to the carburetor 14, and the air-fuel ratio is made leaner than the stoichiometric air-fuel ratio.
A signal is also sent to the ignition timing control circuit 38, and the ignition timing is controlled to be advanced from the standard value. Note that when the engine rotational speed is lower than the second predetermined value (and during idle linking when the throttle switch 25 is in the OFF state, the first OR
Since the output of the circuit 62 does not reach 111, the air-fuel ratio is equalized and the ignition timing is not advanced.

Further, the output of the first AND circuit 60 is 11',
Further, when the throttle valve 20 is closed and the engine rotational speed is equal to or higher than the third predetermined value, that is, when the first A
When the conditions of the ND circuit 60 are satisfied and the deceleration state is in effect, the output of the third OR circuit 72 becomes 101, the energization to the slow cut solenoid valve 16 is canceled, and the slow cut or slow system is activated. Air bleed is performed.

In this embodiment, when the economic mode is selected,
The air-fuel ratio is leaner than the stoichiometric air-fuel ratio, the ignition timing is advanced from the standard value, and exhaust gas recirculation and idle up are not performed, which improves drivability in economy mode. and even higher fuel efficiency. Note that it is of course possible to perform idle up in the economy mode.

Furthermore, in this embodiment, when the output mode is selected, fuel cut during deceleration is stopped, so drivability during re-acceleration is excellent. In addition, if the fuel cut is not stopped during deceleration, or
It is also possible to narrow the fuel cut range.

In the above embodiment, an exhaust gas recirculation device is provided to recirculate exhaust gas, but in an automobile engine equipped with a three-way catalyst, the EGR device can be omitted even when used as a high-performance engine. There is. Of course, the present invention can be applied to the same bucket even in such a case.

Further, in the above embodiments, the present invention provides a capretor (
Although the present invention has been applied to a fitted automobile engine, the scope of application of the present invention is not limited thereto, and is applicable to an automobile engine equipped with an electronically controlled fuel injection device, or a general automobile engine. It is clear that the same applies to institutions.

As explained below, according to the present invention, in a vehicle equipped with a single engine, a driving state with excellent cost performance and a running state can be set depending on the driver's preference or the usage state. It becomes possible to freely select an excellent operating condition. Moreover, exhaust gas purification performance and drivability are often impaired. Furthermore, it has excellent effects such as low production costs.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the air-fuel ratio and nitrogen oxide emissions, which is beyond the scope of a detailed explanation of the present invention, and FIG. 2 is a diagram showing the relationship between the air-fuel ratio and the amount of nitrogen oxide emissions, and FIG. Fig. 3 is a block diagram showing the main part configuration of the electronic control unit used in the embodiment. . 10...Engine, 14...Cab 1) Evening, 16.
...Solenoid valve for slow cut, 1B...Switching valve for lean bleed, 20...Throttle valve, 22...Dash pot, 24...Solenoid valve for canceling idle up, 34...For EGR control switching valve, 360. , negative pressure switch, 38... Ignition timing control circuit, 45... Engine rotation sensor, 46... Water wetness sensor, 48... Mode selection switch, 50... Electronic control unit. Agent Takaya Ron (and 1 other person)

Claims (3)

[Claims] (1) A mode selection switch for selecting economy mode or output mode in an internal combustion engine control device that controls the air-fuel ratio, ignition timing, etc. based on output signals from sensors installed in various parts of the engine. is provided, and when the economy mode is selected by the mode selection switch, at least the air-fuel ratio in the normal operating state is set to the side of the stoichiometric air-fuel ratio, and the ignition timing is set to the side of the standard value. On the other hand, when the output mode is selected, at least the air-fuel ratio in the normal operating state is set to be near the stoichiometric air-fuel ratio, and the ignition timing is set to a standard value. (2) The control device for an internal combustion engine according to claim 1, wherein when the economy mode is selected by the mode selection switch, exhaust gas recirculation and idle up are not performed. (3) The control device for an internal combustion engine according to claim 1, wherein when the mode selection switch selects the output mode, the fuel cut range during deceleration is narrowed.