JPH0411745B2 - - 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, it is necessary for the internal combustion engine's rotation speed to respond quickly to the next accelerator operation. 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 possible to effectively improve fuel efficiency especially when the engine is stopped, such as when waiting at a traffic light or when stopped, and further improves the efficiency of the engine during the fuel efficiency improvement state. It is an object of the present invention to provide an idle control device for an internal combustion engine that provides stable rotation and good responsiveness when attempting to start the engine and performs stable engine operation control.

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 in a light load state is reached, the idle speed is lowered from a steady idle speed to a sustainable speed, and the ignition timing is controlled to be advanced. The engine rotation speed is controlled to be set to a higher rotation speed than the low rotation setting state when the change in the engine speed is detected.

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.

The air conditioner switch 12 determines whether the vehicle-mounted air conditioner is in use or not, and generates a detection signal that goes high ("H") when the air conditioner is in use. The battery voltage detection circuit 13 determines whether the voltage of the battery installed in the vehicle is in a normal state or if it is below "BV" which requires charging. Outputs a detection signal. Furthermore, the parking brake switch 14, clutch switch 15, and neutral switch 16 are controlled in response to the operation of transmissions driven by the parking brake lever, clutch pedal, and shift lever, respectively. When the shift lever is pressed into the neutral position, an "H" level detection signal is output. Further, the throttle fully closed switch 17 works in conjunction with a throttle valve (not shown) to switch to "H" when the throttle valve is fully closed.
The water temperature sensor 18 outputs a level detection signal, and the water temperature sensor 18 uses a detection element whose resistance value changes depending on the temperature of the cooling water of the internal combustion engine (not shown). Generates an "H" level detection signal when the temperature is higher than "T°C".
Further, in the engine rotation speed detection circuit 19, based on an ignition signal output from a primary terminal of an ignition coil of an internal combustion engine (engine) not shown, for example,
It detects and outputs a signal corresponding to the rotational speed N of the engine, and the vehicle speed detection circuit 20 may be a conventionally known circuit that detects the vehicle speed from the rotational speed of the wheels, for example. Then, the vehicle speed detection circuit 20 outputs a low ("L") signal when the speed is below "1 km/h", which is considered to be almost stationary.
The configuration is such that when the speed exceeds 1 km/h, a detection signal that goes to the "H" level is output.

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, and this idle condition discrimination control device 21 receives the detection signal from the detection section 11 as shown in FIG. An input section 22 to which the detection signal 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, an output drive section 24 that extracts the idle control signal from this determination section 23, and the above-mentioned Input section 22, determination section 23,
It consists of a power supply section 25 for an output drive section 24, and is configured to control and drive an idle rotation speed control device 26 and an idle ignition timing control device 27 by the output drive section 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, under 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 ". When the air conditioner is in operation, the battery voltage is in a charging required state, that is, below "BV", or the water temperature is below "T°C", the idle speed is set and controlled by slightly increasing it. In addition, when the car is stopped, the idle speed is set to be lower than "N _STD ", and if the engine speed fluctuation after setting control is "ΔN" or more, the idle speed is set to "N _STD" . ”
Set to control. Further, even if the idle speed is "N _STD ", if the engine speed fluctuation is more than "ΔN" due to smoldering plugs, etc., the idle speed is increased slightly and controlled.

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. This engine ignition timing control device 27 sets the engine ignition timing to the standard ignition timing "θ STD" when the above-mentioned standard idle speed "N _{STD "} or a slightly higher rotation speed is set, Particularly under specific idling conditions when stopped, the engine ignition timing is advanced so that a stable rotational state is maintained even at a low rotational speed at which the engine can continue to rotate.

FIG. 3 is a diagram illustrating the operation of the device configured as described above. A flowchart showing the operation of the condition determination unit 23 is shown.
First, it is determined that the throttle switch 17 has detected that the throttle is fully closed, that is, the engine is in an idle state, and the process starts from step 200.

In the state of this start step 200, as shown in step 201, a state is made in which a signal necessary for determining the idle condition from the detection section 11 is read. That is, the air conditioner switch signal, battery voltage drop signal, parking brake switch signal, neutral switch signal, water temperature sensor signal, engine speed signal, vehicle speed signal, etc. are read. Then, in step 203, it is determined whether or not the parking brake is pulled, and if the driver has no intention of moving the vehicle by pulling the parking brake and the vehicle is definitely stopped, the process proceeds to the next step 205. In addition, even if the parking brake is not applied, the vehicle speed is set to ``0'' in step 204.
Km/h", and if it is determined that the vehicle is stopped, the process proceeds to step 205. However, if the parking brake is not pulled and the vehicle speed is 1 km/h or higher and it is determined that the vehicle is running,
It is determined that the vehicle is in a deceleration state or a shift position change state, and the process proceeds to steps 240 and 241.

In other words, in this state, a command is issued to set the engine's ignition timing ``θ'' and rotational speed target value ``N'' to the standard ignition timing ``θ <sub>STD</sub> '' and rotational speed ``N _STD '', respectively, and when decelerating or shifting. Set to compensate for the decrease in feeling when changing. 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 it is determined whether or not the driver intends to start the vehicle immediately, although the vehicle is currently stopped. 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. Further, if it is determined in step 205 that the shift position is not neutral, then step 205 is determined.
If the clutch pedal position is detected in step 6 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 20.
Proceed to step 7. If in this step 206, the clutch pedal is not fully depressed but is being operated with the clutch pedal released even slightly for starting, the steps 240 and 241 are performed.
Then, control is performed so that "θ=θ _STD " and "N=N _STD " as described above.

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". That is, when the cooling water temperature exceeds "T.degree. C.", it is determined that the warm-up state is reached, and if the cooling water temperature is below "T.degree. C." and the warming-up is insufficient, the process proceeds to step 220. Step 220,
In 221, the ignition timing "θ" at idle is set to the standard value "θ _STD ", and the target rotation speed "N" at idle is set to "N" which is higher than the standard value (N _STD ). N _STD ) + warm-up correction amount (N _T ). It is effective to set the warm-up correction value " _NT " to an appropriate value in stages according to the water temperature.

If it is determined in step 207 that the machine is warmed up, the process proceeds to step 208, where it is determined whether or not the air conditioner is being used.If the air conditioner is being used, the process proceeds to step 230.
Go to ``θ <sub>STD'</sub> ' and set the ignition timing at idle to ``θ''.
In step 231, set the target rotation speed "N" to "N=N _STD + N _A " which is slightly higher than the standard value (N _STD ).
(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 210. , and if it is less than "BV", the process proceeds to step 240, and "θ=θ _STD "
Prevents battery voltage drop as "N-N _STD ".
Also, when the battery voltage is higher than "BV",
Proceeding to step 210, it is determined whether the fluctuation in the engine speed is less than " _ΔN1 ", and if the fluctuation in the engine speed is more than " _ΔN1 ", it is determined that the engine condition is extremely unstable, Step 250,2
Proceed to step 51. In step 250, the ignition timing "θ" during idling is set to "θ _STD ", and step 2
51, the target rotational speed "N" is set to "N _STD + ΔN _i " which is slightly higher than the standard value (N _STD ) (where ΔN _i is the drivability correction value). If the variation in engine speed is less than ΔN ₁ , the process proceeds to step 211.

In step 211, it is determined whether the fluctuation in the engine speed is less than "ΔN ₂ " (here, of course, ΔN ₂ < ΔN ₁ ), and if the fluctuation in the engine speed is more than "ΔN ₂ ". In this case, it is determined that the engine condition is unstable, and steps 240 and 240 are performed.
Proceed to 241. In step 240, the ignition timing "θ" during idling is set to "θ _STD ", and in step 241, the target rotational speed "N" is set to "N _STD ". If the variation in engine speed is less than ΔN ₂ , the process proceeds to steps 212 and 213.

In step 212, the ignition timing "θ" during idling is advanced by the idle specific condition advance angle "Δθi" from the standard value (θ _STD ). In other words, “θ=
θ _STD + Δθi” to reduce the fuel consumption during idling, and in step 213 the idle speed is reduced to “N”.
is lowered by the idle special condition rotation speed ΔN _i from the standard value (N _STD ), and as "N=N _STD − ΔN _i ",
Reduces fuel consumption at idle.

That is, when the vehicle is in an idling state and the vehicle is not started, and when the combustion state of the engine is stable, the engine speed is lowered to reduce fuel consumption. Furthermore, when the vehicle is about to start, or when the combustion state of the engine is unstable due to changes in the engine over time, the engine rotational speed is maintained or increased to prevent a drop in engine speed when idling.

FIG. 4 shows a flowchart in the case of an automatic transmission without a clutch mechanism, and parts corresponding to those in FIG. 3 are given the same reference numerals and their explanation will be omitted. That is, in this embodiment, it is only necessary to determine whether the shift position is in neutral, and to omit signals related to the clutch switch.

Note that the means for increasing the idle rotation speed setting value upon detection of a rotational fluctuation of a predetermined value or more may include means for increasing the fuel injection amount.

As described above, according to the present invention, the vehicle is stopped while the internal combustion engine is determined to be in the idle state.
When the second idle condition is satisfied, the internal combustion engine is disconnected from the wheels, the air conditioner load is inactive, and the vehicle battery voltage is normal.
At least one of these is not satisfied. Set the ignition timing to a sustainable low rotation speed that is lower than the steady idle speed set under the first idle condition, and further set the ignition timing to the steady idle ignition speed set under the first idle condition. By advancing the timing by a predetermined amount, it is possible to effectively reduce fuel consumption during a specific light load idling operation, and further to increase the engine speed when the engine condition is unstable under the second idling condition. It is possible to prevent a drop in drivability without using a vibration detector, effectively maintain a stable operating state of the engine, and improve operational responsiveness.

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 further set to the normal idle ignition timing. It is possible to prevent the battery voltage from dropping by detecting the battery voltage, and since there is no need to detect the operation status of the electric load's operating switch, no matter what kind of electric load is connected, the battery voltage can be detected. This 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.
Figure 3 is a flowchart explaining the operation of the above device;
The figure is a flowchart illustrating another embodiment. 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), and a state in which the engine is determined to be in an idle state by this means (17, step 200), and in a state determined to be the first idle condition, 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 (Step 2
40, 241), and when the idle state is determined by the means (17, step 200) and the second idle condition is determined, the engine speed N is set to the steady state set under the first idle condition. means for setting the idle rotation speed N _STD to a sustainable low rotation speed N _STD −ΔNi that is lower than the idle rotation speed N STD, and further advancing the ignition timing θ by a predetermined amount Δθi from the steady idle ignition timing θ _STD (steps 212 and 213); Means for detecting a change in the engine speed N of a predetermined value or more under the second idle condition (step 21)
0, 211), and means (steps 241, 251) for increasing the idle rotation speed set value upon detection of rotation speed fluctuations exceeding the predetermined value, and determines the first and second idle conditions. The means for detecting the operating state of the air conditioner load (1)
2. Step 208), means for detecting whether the voltage of the vehicle battery is in a normal state (13. Step 2)
09), means for determining whether or not the internal combustion engine and the wheels are connected (15, 16, step 2)
05, 206), and means (14, 20, step 20) for determining whether the vehicle is stopped according to the vehicle speed and the operating state of the parking brake.
3,204), wherein the vehicle is stopped and the internal combustion engine is disconnected from the wheels when the internal combustion engine is determined to be in an idle state by the means;
When the air conditioner load is inactive and the vehicle battery voltage is normal, it is determined that the second idle condition is met, and the vehicle is stopped with the internal combustion engine determined to be idle by the means described above. The first idle condition is determined when at least one of the following conditions is not satisfied: the internal combustion engine is disconnected from the wheels, the air conditioner load is inactive, and the voltage of the vehicle battery is normal. Features: Idle control device for internal combustion engines. 2. The device according to claim 1, wherein the means for increasing the idle rotation speed set value upon detection of a rotation speed fluctuation greater than the predetermined value includes means for increasing the injection amount.