JP6833273B2 - Vehicle control device - Google Patents

Description

The present invention relates to a control device for an idle stop vehicle.

It is known to perform an idle stop system for stopping the idle rotation of an internal combustion engine while the vehicle is stopped due to waiting for a traffic light or the like (see, for example, the following patent documents). In a typical idling stop system, the vehicle speed is 0, the brake pedal is depressed, the slope of the road surface on which the vehicle is located is not large, the cooling water temperature of the internal combustion engine and the voltage of the in-vehicle battery are sufficiently high, etc. When all of the above is established, the internal combustion engine is stopped. During idle stop, the internal combustion engine is restarted when the driver requests a restart such as releasing the brake pedal or depressing the accelerator pedal.

Japanese Unexamined Patent Publication No. 2013-136267

In the case of executing an idle stop when the vehicle is stopped, the conventional system waits for a predetermined delay time (for example, 200 milliseconds) to elapse from the time when the vehicle speed becomes 0, and then the rear accelerometer (for example, 200 milliseconds). The slope of the road surface was known through the G sensor), and it was determined whether or not the slope was within the permissible range. This is because pitching, that is, swaying motion in the front-rear direction occurs due to the braking of the vehicle, which adversely affects the measurement of the road surface gradient by the accelerometer. By trying to judge the permission.

However, when the vehicle speed becomes 0, the idle stop execution cannot be started immediately, and there is a tendency that extra fuel consumption is caused during the delay time.

The present invention has been made by paying attention to the above problems for the first time, and an object of the present invention is to enable the idle stop system to be immediately started to be executed when the vehicle speed becomes 0.

In the present invention, when the vehicle speed of the vehicle drops to a predetermined extremely low speed value other than 0, the slope of the road surface on which the vehicle is located is detected via an acceleration sensor, and the slope of the road surface is within a predetermined first permissible range. Ah is, and on condition that it is determined that the vehicle speed becomes 0 until the vehicle speed has passed a certain time from the time when decreased to extremely low speed value, to allow idle stop of the engine immediately after stoppage of the vehicle At the same time, the slope of the road surface detected when the vehicle speed drops to the extremely low speed value is not within the first allowable range, or the vehicle speed is between the time when the vehicle speed drops to the extremely low speed value and a certain time elapses. Even if it is determined that the vehicle speed does not become 0 and then the vehicle speed becomes 0, the slope of the road surface on which the vehicle is located is determined via the acceleration sensor after a predetermined delay time has elapsed from the time when the vehicle speed is determined to be 0. It constitutes a vehicle control device that allows idle stop of the internal combustion engine after the vehicle is stopped, provided that the slope of the road surface is within a predetermined second allowable range wider than the first allowable range. did.

According to the present invention, the idle stop execution can be started immediately when the vehicle speed becomes 0.

The figure which shows the structure of the internal combustion engine and the control device in one Embodiment of this invention. The flow chart which shows the procedure example of the process which the control device of the same embodiment executes according to a program.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an internal combustion engine for a vehicle according to the present embodiment. The internal combustion engine in the present embodiment is a spark-ignition type 4-stroke engine, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). An injector 11 for injecting fuel is provided in the vicinity of the intake port of each cylinder 1. Further, a spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives the application of the induced voltage generated by the ignition coil and induces a spark discharge between the center electrode and the ground electrode.

The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1. An air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream on the intake passage 3.

The exhaust passage 4 for discharging the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 1 to the outside from the exhaust port of each cylinder 1. An exhaust manifold 42 and a three-way catalyst 41 for purifying exhaust gas are arranged on the exhaust passage 4.

The external EGR (Exhaust Gas Recirculation) device 2 realizes a so-called high-pressure loop EGR. The EGR device 2 includes an external EGR passage 21 that connects the upstream side of the catalyst 41 in the exhaust passage 4 and the downstream side of the throttle valve 32 in the intake passage 3, an EGR cooler 22 provided on the EGR passage 21, and an EGR passage 21. The element is an EGR valve 23 that opens and closes and controls the flow rate of the EGR gas flowing through the EGR passage 21. The inlet of the EGR passage 21 is connected to the exhaust manifold 42 in the exhaust passage 4 or a predetermined position downstream thereof. The outlet of the EGR passage 21 is connected to a predetermined position downstream of the throttle valve 32 in the intake passage 3, specifically, the surge tank 33.

The vehicle of the present embodiment is provided with a brake booster 5 for reducing the operating force required for braking, that is, the pedaling force of the brake pedal. In this field, the brake booster 5 draws in intake negative pressure from a portion (or surge tank 33) on the downstream side of the throttle valve 32 in the intake passage 3, and uses the negative pressure to boost the pedaling force of the brake pedal. It is widely known. The brake booster 5 has a constant pressure chamber for storing negative pressure and a transformer chamber to which atmospheric pressure is applied, and the constant pressure chamber is connected to the intake passage 3 via a negative pressure pipeline 51. The negative pressure pipeline 51 guides the intake negative pressure on the downstream side of the throttle valve 32 to the constant pressure chamber. A check valve 52 is provided on the negative pressure conduit 51 to keep the negative pressure in the constant pressure chamber and prevent the positive pressure from being applied to the constant pressure chamber.

When the brake pedal is not operated by the driver, the constant pressure chamber and the transformer chamber communicate with each other, and the transformer chamber is isolated from the atmospheric pressure. When the brake pedal is operated, the constant pressure chamber and the transformer chamber are cut off, and air is introduced into the transformer chamber. As a result, the pressure difference between the constant pressure chamber and the transformer chamber becomes the control pressure that doubles the pedaling force of the brake pedal. The brake pedal force amplified by the brake booster 5 is converted into hydraulic pressure in the master cylinder 6. The hydraulic pressure output from the master cylinder 6 is transmitted to a braking device (not shown) such as a brake caliper or a wheel cylinder via a hydraulic circuit (not shown), and is used for braking the vehicle by the braking device.

The ECU (Electronic Control Unit) 0, which is a vehicle control device of the present embodiment, is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like.

The input interface includes a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal b output from an engine rotation sensor that detects the rotation angle of the crank shaft and the engine rotation speed, and depression of the accelerator pedal. The accelerator opening signal c output from the sensor that detects the amount or the opening degree of the throttle valve 32 as the accelerator opening, the sensor that detects the depression amount of the brake pedal, or the master that is the pressure of the working fluid discharged from the master cylinder 6. Brake depression signal d output from the sensor that detects the cylinder pressure, intake temperature / intake pressure signal that is output from the temperature / pressure sensor that detects the intake temperature and intake pressure in the intake passage 3 (particularly, surge tank 33). e, the cooling water temperature signal f output from the water temperature sensor that detects the cooling water temperature of the internal combustion engine (indicating the temperature of the internal combustion engine), and the shift output from the sensor (shift position switch) for knowing the range of the shift lever. Range signal g, brake booster negative pressure signal h output from a pressure sensor that detects the magnitude of negative pressure stored in the brake booster 5, atmospheric pressure signal p output from a sensor that detects atmospheric pressure, vehicle location An acceleration signal q or the like output from an acceleration sensor (G sensor) that detects the slope of the road surface is input.

From the output interface, the ignition signal i for the igniter of the spark plug 12, the fuel injection signal j for the injector 11, the opening operation signal k for the throttle valve 32, and the opening operation signal l for the EGR valve 23. Etc. are output.

The processor of ECU 0 interprets and executes a program stored in the memory in advance, calculates an operation parameter, and controls the operation of the internal combustion engine. The ECU 0 acquires various information a, b, c, d, e, f, g, h, p, q necessary for the operation control of the internal combustion engine via the input interface, obtains the engine speed, and cylinders 1 Estimate the amount of intake air charged in. Then, based on the engine speed, intake amount, etc., the required fuel injection amount, fuel injection timing (including the number of fuel injections for one combustion), fuel injection pressure, ignition timing, required EGR rate (or EGR). Determine various operating parameters such as gas volume). The ECU 0 applies various control signals i, j, k, l corresponding to the operation parameters via the output interface.

The ECU 0 of the present embodiment executes an idle stop system for stopping the idle rotation of the internal combustion engine when a predetermined idle stop condition is satisfied. In ECU0, the brake pedal depression amount or master cylinder pressure is equal to or higher than the threshold value (brake pedal is depressed), the cooling water temperature of the internal combustion engine is higher than a predetermined value, and the charge amount or terminal voltage of the vehicle-mounted battery is higher than the predetermined value. High, the shift range is the driving range, the absolute value of the slope of the road surface where the vehicle is located is less than the specified value, and the negative pressure stored in the brake booster 5 (difference pressure between the atmospheric pressure and the brake booster negative pressure). The size of the vehicle is equal to or greater than the threshold value, the vehicle has a history of accelerating to a certain vehicle speed (for example, 10 km / h) or more since the end of the previous idle stop, and the vehicle speed has become 0. , Judge that the idle stop condition is satisfied.

FIG. 2 shows an example of a procedure of processing executed by ECU 0 when determining the success or failure of the idle stop condition. ECU0 measures the magnitude of the slope of the road surface and stores it in the memory when the vehicle speed drops to an extremely low speed value of 2 km / h or its vicinity (step S1) before the vehicle completely stops. (Step S2).

The slope of the road surface on which the vehicle is currently located is decremented from the output signal q of the acceleration sensor (indicating the apparent road surface slope) and the output signal a of the vehicle speed sensor (indicating the apparent road surface slope) associated with the ABS (Antilock Break System). Should be known) by referring to (suggesting vehicle deceleration). However, when the vehicle is braked and stopped, pitching, which is a swinging motion of the vehicle in the front-rear direction due to the braking, occurs, which affects the acceleration sensor. Therefore, the S / N ratio of the output signal q of the acceleration sensor at the moment when the vehicle speed becomes 0 is low. On the other hand, the S / N ratio of the output signal q of the acceleration sensor is sufficiently high at the time when the vehicle speed drops to an extremely low speed value of about 2 km / h before the vehicle completely stops. Steps S1 and S2 are intended to measure the slope of the road surface at a time when the reliability of the acceleration sensor is relatively high.

Then, when it is determined that the vehicle speed becomes 0 (the vehicle has stopped) between the time when the vehicle speed reaches the extremely low speed value of about 2 km / h and the time when a certain time elapses (steps S3 and S4). ), It is determined whether or not the value of the slope of the road surface measured in step S2 is within the first permissible range (step S5). The first permissible range is, for example, a range from 4.5% downhill to 5.5% uphill. Then, if the slope of the road surface is within the first allowable range, it is determined that the vehicle speed has become 0 on condition that the idle stop condition other than the slope of the road surface is satisfied (step S6). At that point, the execution of the idle stop is immediately started (step S7).

On the other hand, when the vehicle speed becomes 0 after a certain time has elapsed from the time when the vehicle speed reaches the above-mentioned extremely low speed value, or the value of the road surface gradient stored in step S1 is within the first allowable range. If it is determined that the vehicle speed does not fall within the above range, wait for a predetermined delay time to elapse from the time when the vehicle speed is determined to be 0 (step S8), and then refer to the output signal q of the acceleration sensor to display the road surface. Know the magnitude of the gradient (step S9). The delay time is, for example, 200 milliseconds. Steps S8 and S9 are intended to measure the slope of the road surface after the pitching generated when the vehicle is stopped has subsided.

Then, it is determined whether or not the value of the slope of the road surface measured in step S9 is within the second allowable range (step S10). The second tolerance is wider than the first tolerance, for example, from 8% downhill to 8% uphill. Then, if the slope of the road surface is within the second allowable range, the execution of the idle stop is started on condition that the idle stop condition other than the slope of the road surface is satisfied (step S11). (Step S12). Otherwise, the idle stop associated with the vehicle stop will not be performed. The start of the idle stop execution in step S12 is at least after the above-mentioned delay time has elapsed since the vehicle stopped.

When the vehicle speed once drops to an extremely low speed value of about 2 km / h, but then accelerates to exceed the extremely low speed value again (step S13), the routine shown in FIG. 2 is exited and the vehicle speed increases again. When the value drops to the extremely low speed value, the process is restarted from step S1.

After the idle stop condition is satisfied, the internal combustion engine is restarted when the predetermined idle stop end condition is satisfied. In ECU0, the depression amount of the brake pedal or the master cylinder pressure became 0 or less than the threshold value close to 0 (the brake pedal was not depressed), and conversely, the depression amount of the brake pedal or the master cylinder pressure further increased (brake). The pedal was depressed more strongly), the accelerator opening was increased (the accelerator pedal was depressed), the magnitude of the negative pressure stored in the brake booster 5 decreased below the threshold, and a predetermined time (in an idle stop state). It is judged that the idle stop end condition is satisfied by any of the following, such as the elapse of 3 minutes).

When starting a stopped internal combustion engine (including not only returning from idling stop but also cold starting), ECU 0 inputs a control signal o to an electric motor (starter or ISG (Integrated Starter Generator), not shown). , The crankshaft is cranked by the electric motor. Cranking ends when the internal combustion engine goes from the first explosion to the continuous explosion and the engine speed, that is, the rotation speed of the crankshaft exceeds the judgment value determined according to the cooling water temperature, etc. (assuming that the explosion has been completed). To do.

In the present embodiment, when the vehicle speed of the vehicle drops to a predetermined extremely low speed value other than 0, the slope of the road surface on which the vehicle is located is detected via an acceleration sensor, and the slope of the road surface is within a predetermined first permissible range. The vehicle control device 0 that allows the idle stop of the internal combustion engine immediately after the vehicle is stopped is configured on the condition that the vehicle is in the above condition.

According to the present embodiment, it is possible to immediately start the execution of the idle stop when the vehicle speed becomes 0, and it is possible to reduce the extra fuel consumption.

The present invention is not limited to the embodiments described in detail above. For example, an internal combustion engine does not always include an external EGR device 2.

In addition, the specific configuration of each part can be variously modified without departing from the spirit of the present invention.

The present invention can be applied to the control of a vehicle equipped with an internal combustion engine.

0 ... Control device (ECU)
a ... Vehicle speed signal q ... Acceleration signal

Claims (1)

The gradient of the road surface on which the vehicle is located and detected via the acceleration sensor when the vehicle speed decreases to a predetermined extremely low speed value is not 0, Ri first permissible range near the slope is in a predetermined its road surface, and On the condition that it is judged that the vehicle speed has become 0 between the time when the vehicle speed drops to the extremely low speed value and the time when a certain time elapses , the idle stop of the internal combustion engine immediately after the vehicle is stopped is allowed .
The road surface gradient detected when the vehicle speed drops to the extremely low speed value is not within the first allowable range, or the vehicle speed is 0 from the time when the vehicle speed drops to the extremely low speed value until a certain time elapses. Even if it is determined that the vehicle speed has become 0 after that, the slope of the road surface on which the vehicle is located is detected via the acceleration sensor after a predetermined delay time has elapsed from the time when the vehicle speed is determined to be 0. , A vehicle control device that allows idle stop of the internal combustion engine after the vehicle has stopped, provided that the slope of the road surface is within a predetermined second tolerance that is wider than the first tolerance.

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