JPH0411744B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an internal combustion engine that further reduces fuel consumption under specific idling conditions such as light load driving, such as waiting at a traffic light or stalling, in a vehicle equipped with an internal combustion engine. The present invention relates to an idle control device.

In an automobile, when the foot is removed from the accelerator pedal, the installed internal combustion engine is controlled to rotate at a specified idle speed. The idle rotation speed is set to the specified rotation speed even when the vehicle is still running or when the vehicle is stopped at a traffic light or the like.

The set idle speed is such that the internal combustion engine can continue to rotate smoothly in a state where there is no load, and at the same time, it is necessary to keep the engine speed at a speed with sufficient response when the accelerator is operated next time. It is necessary to be able to control the increase. In particular, when the accelerator is temporarily released to shift gears while driving, the internal combustion engine's rotational speed needs to respond quickly to the next accelerator operation, and this is due to the type of engine, etc. Although it differs depending on the vehicle, the idle speed is set to about 800 rpm, for example.

However, in such an idling operation control state, for example, if there are many states of waiting at traffic lights or stagnant driving, fuel consumption during the idling operation increases, which becomes one of the obstacles to improving fuel efficiency.

This invention has been made in view of the above points, and it is an object of the present invention to provide an idle control device for an internal combustion engine that can effectively improve fuel efficiency especially when stopped at a traffic light or stopped. It is.

That is, the idle control device according to the present invention determines idle load conditions such as when starting, when using an air conditioner, and when using electrical loads such as wipers and headlights, and specifically deals with stopping such as waiting at a traffic light or stopping. When a specific idle condition of a light load state is reached, the idle rotation speed is reduced from a steady idle rotation state to a sustainable rotation speed, and the ignition timing is controlled to be advanced.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows its configuration, which includes a driving situation detection section 11. This detection section 11 includes an air conditioner switch 12, a battery voltage detection circuit 13, a parking brake switch 14, a clutch switch 15, a neutral switch 16, a throttle fully closed switch 17, a water temperature sensor 18, an engine speed detection circuit 19, and a vehicle speed detection circuit. Consists of 20. Here, the air conditioner switch 12 determines whether the air conditioner installed in the vehicle is in use or not, and generates a detection signal that goes high when the air conditioner is in use. The battery voltage detection circuit 13 determines whether the voltage of the battery mounted on the vehicle is in a normal state or is below BV, which requires charging, and outputs an H level detection signal in a normal state above BV. Furthermore, the parking brake switch 14, clutch switch 15, and neutral switch 16 are controlled in response to the operation of the transmission, etc. driven by the parking brake lever, clutch pedal, and shift lever, respectively, and lock the rotation of the wheels. H when the parking brake is used, when the clutch is depressed to release the connection between the internal combustion engine and the wheels, and when the shift lever is placed in the neutral position.
Outputs level detection signal. Further, the throttle fully closed switch 17 works in conjunction with a throttle valve (not shown) to output an H level detection signal that recognizes idling operation when the throttle valve is fully closed, and the water temperature sensor 18 detects the temperature of the cooling water of the internal combustion engine (not shown). Accordingly, by using a detection element whose resistance value changes, an H level detection signal is generated when the cooling water temperature is equal to or higher than a temperature T° C. at which the internal combustion engine can operate smoothly.

Furthermore, the engine speed detection circuit 19 detects and outputs a signal corresponding to the engine speed N based on an ignition signal output from the primary terminal of an ignition coil of an internal combustion engine (not shown), for example. The vehicle speed detection circuit 20 includes:
For example, a conventionally known method for detecting the vehicle speed from the rotational speed of the wheels may be used. The vehicle speed detection circuit 20 is configured to output a detection signal that is at a low "L" level when the speed is below 1 km/h, which is considered to be almost stationary, and becomes "H" level when the speed exceeds 1 km/h. .

The detection signal from the engine operating condition detection section 11 configured as described above is supplied to the idle condition discrimination control device 21.
As shown in FIG. 2, there is an input section 22 to which the detection signal from the detection section 11 is coupled, an idle condition determination section 23 to which the input detection signal is supplied from this input section 22 and forms an idle control signal, and this determination section. Output drive unit 24 that extracts the idle control signal from 23, the input unit 22, the determination unit 23, and the output drive unit 2
The idle speed control device 26 and the idle ignition timing control device 27 are controlled and driven by an output drive portion 24 to which an idle control signal is supplied.

The idle speed control device 26 is attached to the intake pipe system of the engine (not shown), and may be configured by, for example, a conventionally known ISC system, and controls the detected engine speed to a specified idle speed. It is controlled so that it is set to . For example, in normal driving conditions, when the accelerator pedal is released and the throttle is fully closed, which is the idle condition, the engine speed is basically set to the standard idle speed N _STD , and at this time the air conditioner is turned off. When the battery voltage is in the operating state and the battery voltage needs charging, i.e.
When the water temperature is below BV or below T°C, the idle speed is slightly increased to control the setting. Also, when the car is stopped, the idle speed is set to be lower than N _STD .

The idle ignition timing control device 27 varies the timing of an ignition signal supplied to an ignition coil (not shown) in accordance with a command from the idle condition determination device 21. It is constructed by incorporating two different magnetic pickups and controlling the selection and switching of one of them. The engine ignition timing control device 27 sets the engine ignition timing to the standard ignition timing θ _STD when the engine speed is set to the standard idling speed N _STD or a slightly higher speed, especially when the engine is stopped. Under specific idle conditions, the engine ignition timing is advanced so that the engine can stably maintain its rotational state even at a low rotational speed that is unsustainable.

FIG. 3 shows a specific example of the configuration of the idle condition determining section 23, in which signals from the parking brake switch 14 and the neutral switch 16 are supplied to OR circuits 28 and 29, respectively.
The OR circuit 28 is further supplied with a signal from an inverter 30 to which the detection signal from the vehicle speed detection circuit 16 is supplied, and the OR circuit 29 is supplied with a signal from the clutch switch 1.
The OR circuits 28,
The output signal from 29 is supplied to an AND circuit 31. This AND circuit 31 further includes a water temperature sensor 1.
8 and the battery voltage detection circuit 13, and an output signal from the inverter 36 to which the output signal from the air conditioner switch 12 is supplied. The output signal from this AND circuit 31 is supplied to an AND circuit 37 and also to an AND circuit 39 via an inverter 38.
7 and 39, a throttle fully closed signal from the throttle fully closed switch 17 is given as a gate signal.

Further, the output signal from the throttle fully closed switch 17 and the output signals from the OR circuits 28 and 29 are supplied in parallel to AND circuits 40 and 41, and the AND circuit 40 is further supplied with a water temperature sensor 18.
The output signals from the water temperature sensor 18 and the air conditioner switch 12 are supplied to the AND circuit 41.

FIG. 4 is a flowchart showing the operation of the idle condition determination unit 23 as shown in FIG. So, in this flowchart, throttle switch 17
When it is determined that the throttle is fully closed, that is, the idle state has been reached, the process starts from step 200. In FIG. 3, this start state is determined by AND circuits 37, 39, 4 which generate command signals for the engine speed and ignition timing during idling in response to the rising edge of the signal from the throttle switch 17.
A gate signal is given to 0 and 41.

Step 201 in this state of start step 200
As shown in FIG. 3, a state is set in which signals necessary for determining the idle condition from the detection section 11 are read. That is,
Air conditioner switch signal, battery voltage drop signal,
Parking brake switch signals, neutral switch signals, water temperature sensor signals, engine speed signals, vehicle speed signals, etc. can now be read. Then, in step 203, it is determined whether or not the parking brake is applied, and if the driver does not intend to move the vehicle by applying the parking brake and the vehicle is firmly stopped, the process proceeds to the next step 205. Furthermore, even if the parking brake is not applied, it is determined in step 204 whether the vehicle speed is 0 km/h or not, and if the vehicle is deemed to be stopped, the process proceeds to step 205. Such a determination operation is performed by the OR circuit 28. However, if the parking brake is not applied and the vehicle speed is 1 km/h or higher and it is determined that the vehicle is in a running state, the vehicle is determined to be in a deceleration state or a shift position change state, and steps 240 and 240 are performed.
Proceed to 241. That is, in this state, OR circuit 2
The output of 8 and the output of the AND circuit 31 become L level, and in response to the fully closed throttle, the signal from the AND circuit 39 becomes H level, setting the engine's ignition timing θ and target rotational speed N to the standard values. A command is issued to set the ignition timing θ _STD and rotational speed N _STD to compensate for the decrease in feeling during deceleration or shift change. The rotational speed control in this case is performed by a known ISC system or an alternative system capable of controlling the amount of intake air.

In step 205, it is determined whether the shift position is neutral or not, and whether the vehicle is currently stopped but whether the driver intends to start the vehicle immediately is determined. That is, if the shift position is neutral, it is determined that there is no intention to start the vehicle immediately, and the process proceeds to the next step 207. If it is determined in step 205 that the shift position is not neutral, the process proceeds to step 206.
If the position of the clutch pedal is detected and it is determined that the clutch pedal is fully depressed even if the shift position is not neutral and there is no intention to move the vehicle immediately, the process also proceeds to step 207, and this judgment operation is performed. , is performed by the OR circuit 29. If, in this step 206, the clutch pedal is not fully depressed, but is operated with the clutch pedal released even slightly to start, the output of the OR circuit 29 will be at the L level. Then, the process proceeds to steps 240 and 241, and the signal from the AND circuit 39 rises as before.
Control is performed so that "θ=θ _STD " and "N=N _STD ".

In step 207, the engine cooling water temperature is detected and the engine warm-up state is determined based on the water temperature T°C. In other words, when the cooling water temperature exceeds T℃, it is determined that the warm-up condition is reached;
If warm-up is insufficient below ℃, proceed to step 220.
Proceed to. In this state, the detection signal from the water temperature sensor 18 is at the L level in FIG. Set the ignition timing θ at the time to the standard value θ _STD , and set the target rotation speed N at idle to be "standard value (N _STD ) + warm-up correction amount (N _T )" which is higher than the standard value (N _STD ). to control. It is effective to set the warm-up correction amount N _T to an appropriate value in stages depending on the water temperature.

If it is determined in step 207 that the engine is warmed up, the process proceeds to step 208, where it is determined whether or not the air conditioner is being used.
When using the air conditioner, use the AND circuit 41 in Figure 3.
The output of the engine rises, and in step 230, the ignition timing θ at idle is set to θ _STD .
231, the target rotation speed N is set slightly higher than the standard value (N _STD ), ``N = N _STD + N _A '' (however, N _A is the air conditioner correction value) to prevent the efficiency of the air conditioner from decreasing.

When it is determined in step 208 that the air conditioner is not in use, the process proceeds to step 209, where a drop in battery voltage due to the use of an electrical load is detected, and if the battery voltage is higher than the preset voltage BV, the process proceeds to step 209.
Proceed to step 210, and if below BV, proceed to step 240
Proceed to. That is, in FIG. 3, the output of the AND circuit 31 becomes L level, and the output of the AND circuit 39 sets "θ=θ _STD " and "N=N _STD " to prevent a voltage drop in the battery.

Furthermore, when the battery voltage is higher than BV, all the inputs of the AND circuit 31 in FIG. 3 become H level, the output of this AND circuit 31 rises to H level, and the output of AND circuit 37 rises to H level. . That is, from step 209
Proceeding to step 210, it is determined that the condition allows the idle rotation speed to be lowered, and first, in step 210, the ignition timing θ is advanced by the idle specific condition advance angle θi from the standard value θ _STD . In other words, by setting θ = θ _STD + θi, the fuel consumption during idling is reduced, and the step
At step 211, the idle speed N is lowered to a sustainable speed. Here, if the rotation reduction width is Ni, it is slightly _lower than the standard value (N _STD ).
Ni'', thereby reducing fuel consumption during idling operation.

The above embodiment shows the case where the transmission mechanism equipped with a clutch mechanism is operated manually, but if the transmission mechanism is automatic and does not have a clutch mechanism, the idle condition determination section 23 can be changed as shown in FIG. The operation flowchart in this case is shown in FIG. In FIGS. 5 and 6, parts corresponding to those in FIGS. 3 and 4 are designated by the same reference numerals, and their explanation will be omitted.

That is, in the case of this embodiment, it is only necessary to determine whether or not the shift position is in neutral, and to omit signals related to the clutch switch, and the OR circuit 29 in FIG. The detection signal from the TRAL switch 16 is directly coupled to the AND circuit 31.

In the above description of the embodiment, the detection signal from the detection unit 11 is processed by the logic circuit, and the standard idle conditions "θ=θ _STD " and "N=N _STD " and the warm-up correction idle condition "θ=θ _STD " are explained. ” “N=N _STD +N _T ” Air conditioner correction idle conditions “θ=θ _STD ” “N=N _STD +N _A ” and specific idle conditions “θ=θ _STD +θi” “N=N _STD −
A signal to command "Ni" is now generated. However, this can be similarly configured using a digital arithmetic processing circuit.

As described above, according to the present invention, when the internal combustion engine is determined to be in the idle state, the vehicle is stopped, the internal combustion engine and the wheels are disconnected, the air conditioner load is inactive, and the voltage of the vehicle battery is At a second idle condition in which all of the normal conditions are satisfied, at least one of these conditions is set to a sustainable low rotation speed that is lower than the steady idle speed set in the first idle condition, and Further, by advancing the ignition timing from the steady idle ignition timing set under the first idle condition, it is possible to effectively reduce fuel consumption during a specific light load idling operation. In particular, when the battery voltage is not in a normal state, it is determined as the first idle condition even if all other conditions are satisfied, the engine speed is set to the normal idle speed, and the ignition timing is set to the normal idle ignition timing. It can be set to prevent battery voltage drop, and there is no need to detect the operation status of the operating switch of this electrical load, so no matter what electrical load is connected,
Detecting the battery voltage has the excellent effect of being able to reliably detect the magnitude of the electrical load.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating an idle control device according to an embodiment of the present invention, and FIG. 2 is a diagram showing an extracted idle condition determination control device section of the device.
FIG. 3 is a configuration diagram illustrating the idle condition discrimination section of the discrimination control device, and FIG. 4 is an operation flowchart,
FIG. 5 is a diagram showing another embodiment of the idle condition determination section, and FIG. 6 is a similar operation flowchart. DESCRIPTION OF SYMBOLS 11... Driving condition detection part, 21... Idle condition discrimination control device, 23... Idle condition discrimination part, 26...
Idle rotation speed control device, 27... Idle ignition timing control device.

Claims (1)

[Scope of Claims] 1. Means for determining first and second idle conditions corresponding to a normal operating state and a specified light load state, respectively, based on operating conditions; and means for determining whether an internal combustion engine is under an idle condition. A means for determining (17, step 200); When the idle state is determined by this means (17, step 200) and the first idle condition is determined, the engine speed N is set to the steady idle speed N. _STD and further sets the ignition timing θ to the steady idle ignition timing θ _STD (39, steps 240, 241); In the state determined to be the idle condition, set the engine rotation speed N to a sustainable low rotation speed N _STD −Ni that is lower than the steady idle rotation speed N _STD set in the first idle condition,
Further, it is provided with means (37, steps 210, 211) for advancing the ignition timing θ from the steady idle ignition timing θ _STD to the light load idle ignition timing θ _STD + θi, and controlling the ignition timing θ to the light load idle ignition timing θ STD + θi. The means for determining includes means (1) for detecting the operating state of the air conditioner load.
2. Step 208), means for detecting whether the voltage of the vehicle battery is in a normal state (13. Step 209);
Means for determining whether or not the internal combustion engine and the wheels are connected (steps 15, 16, 29, step 205,
206), and means for determining whether the vehicle is stopped according to the vehicle speed and the operating state of the parking brake (14, 20, 28, steps 203, 204)
and when the internal combustion engine is determined to be in an idle state by the means, the vehicle is stopped, the internal combustion engine and the wheels are disconnected, the air conditioner load is inactive, and the voltage of the vehicle battery is When all of the normal conditions are satisfied, the second idle condition is determined, and the vehicle is stopped and the internal combustion engine is disconnected from the wheels with the internal combustion engine determined to be in the idle condition by the means. An idle control device for an internal combustion engine, characterized in that when the air conditioner load does not satisfy at least one of the non-operating state and the voltage of the vehicle battery does not satisfy at least one of the normal state, the first idle condition is determined.