JP2014156827A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine which can maintain high drivability while further improving fuel consumption by virtue of idle stop.SOLUTION: In order to execute idle stop when idle stop conditions which contain that a vehicle speed is lowered to a standard vehicle speed or less after the vehicle speed exceeds a controlled permissible vehicle speed as one of the conditions stand up, a plurality of sets of controlled permissible vehicle speed and standard vehicle speed are preset. With respect to the controlled permissible vehicle speed Vand the standard vehicle speed Von a relatively high speed side region, and the controlled permissible vehicle speed Vand the standard vehicle speed Von a relatively high speed side region, the relation of (V-V)<(V-V) stands up.

Description

  The present invention relates to a control device that performs idling stop control for stopping idle rotation of an internal combustion engine.

  Recently, it is becoming common to execute idle stop for stopping idle rotation of an internal combustion engine while the vehicle is stopped by waiting for a signal or the like (for example, refer to the following patent document).

  In the idling stop system, when the vehicle speed falls below a certain reference vehicle speed after exceeding a certain control permission vehicle speed, the brake pedal is depressed, the coolant temperature and battery voltage are sufficiently high, the load by the air conditioner and electrical equipment The success or failure of the conditions such as whether the vehicle is not large or whether the hood or the driver's door is open is determined. If these conditions are satisfied, the internal combustion engine is stopped.

  The engine is restarted when any one of the following conditions is satisfied, such as when the driver removes his or her foot from the brake pedal or depresses the accelerator pedal during idle stop or the idle stop period exceeds 3 minutes. To do.

  In order to further pursue fuel efficiency, it is desirable to extend the idle stop period as much as possible. If the difference between the control-permitted vehicle speed and the reference vehicle speed is set small, the opportunity to determine whether or not the idle stop condition is satisfied increases, and as a result, the number of idle stop executions increases and the idle stop period extends.

  However, simply reducing the difference between the control-permitted vehicle speed and the reference vehicle speed may have a negative effect on drivability. For example, in a situation where the road is congested or congested, the vehicle travels at a relatively low speed while the driver repeatedly depresses and loosens the accelerator pedal. In this case, acceleration and deceleration are inevitably repeated, but if the difference between the control-permitted vehicle speed and the reference vehicle speed is small, the idle stop condition is established even during such low-speed driving, and the idle There is a risk of stopping.

JP 2012-137018 A

  An object of the present invention is to keep drivability high while further improving fuel consumption by idle stop.

In the present invention, after the vehicle speed exceeds the control permission vehicle speed, the rotation of the internal combustion engine is stopped when an idle stop condition that includes one of the conditions that the vehicle speed falls below the reference vehicle speed is satisfied, and then the predetermined idle stop ends. The control for restarting the internal combustion engine when the condition is satisfied is performed, and a plurality of sets of the control permission vehicle speed and the reference vehicle speed are set, and the control permission vehicle speed V _H1 in a relatively high speed region. And the reference vehicle speed V _H2 and the control permission vehicle speed V _L1 and the reference vehicle speed V _L2 in the relatively low speed region, the relationship of (V _H1 −V _H2 ) <(V _L1 −V _L2 ) is established. A control device for an internal combustion engine is configured.

  That is, as a vehicle speed condition for generating an opportunity to determine whether or not idle stop is possible, a control-permitted vehicle speed and a reference vehicle speed are newly set in a relatively high speed region. Then, it becomes possible to start idle stop earlier.

  In addition, if the difference between the control-permitted vehicle speed and the reference vehicle speed in a relatively low speed region is set to be larger than a certain level, there is a risk that the driver will unexpectedly idle stop when the vehicle is running at a low speed. Can be avoided.

  ADVANTAGE OF THE INVENTION According to this invention, drivability can be kept high, aiming at the further improvement of the fuel consumption by idle stop.

The figure which shows the whole structure of the internal combustion engine for vehicles in one Embodiment of this invention. The timing diagram explaining the content of the idle stop control by the control apparatus of the embodiment.

  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 in the present embodiment. The internal combustion engine in the present embodiment is a spark ignition gasoline engine and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). In the vicinity of the intake port of each cylinder 1, an injector 11 for injecting fuel is provided. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives spark voltage generated by the ignition coil and causes spark discharge between the center electrode and the ground electrode. The ignition coil is integrally incorporated in a coil case together with an igniter that is a semiconductor switching element.

  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. On the intake passage 3, 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. The electronic throttle valve 32 is an intake throttle valve that increases or decreases the amount of intake air that flows through the intake passage 3 and fills the cylinder 1.

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

  An ECU (Electronic Control Unit) 0 serving as a control device for an internal combustion engine according to 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 and engine speed of the crankshaft, and depression of an accelerator pedal. An accelerator opening signal c output from a sensor that detects the amount or the opening of the throttle valve 32 as an accelerator opening (so-called required load), and a brake pedaling amount signal d output from a sensor that detects the amount of depression of the brake pedal The intake air temperature / intake pressure signal e output from the temperature / pressure sensor for detecting the intake air temperature and the intake pressure in the intake passage 3 (particularly, the surge tank 33), and the output from the water temperature sensor for detecting the cooling water temperature of the engine. Output from sensor (or shift position switch) to know coolant temperature signal f and shift lever range Shift range signal g that is, the cam angle signal h or the like to be output from the cam angle sensor is input in a plurality of cam angle of the intake camshaft or an exhaust camshaft.

  From the output interface, an ignition signal i is output to the igniter of the spark plug 12, a fuel injection signal j is output to the injector 11, an opening operation signal k is output to the throttle valve 32, and the like.

  The processor of the ECU 0 interprets and executes a program stored in the memory in advance, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 0 acquires various information a, b, c, d, e, f, g, and h necessary for operation control of the internal combustion engine via the input interface, knows the engine speed, and is filled in the cylinder 1. Estimate the intake volume. Based on the engine speed, the intake air amount, and the like, various operating parameters such as required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, and ignition timing are determined. As the operation parameter determination method itself, a known method can be adopted. The ECU 0 applies various control signals i, j, k corresponding to the operation parameters via the output interface.

  Further, the ECU 0 inputs a control signal o to the electric motor (starter motor or motor generator) when the internal combustion engine is started (a cold start or a return from an idling stop). Cranking is performed by rotating the crankshaft. Cranking ends when the internal combustion engine starts from the first explosion to a continuous explosion and the engine speed, that is, the rotation speed of the crankshaft, exceeds a judgment value determined according to the coolant temperature, etc. (assuming that the explosion has been completed) To do.

  The ECU 0 of the present embodiment executes an idle stop that stops the rotation of the internal combustion engine when the idle stop condition is satisfied. Specifically, when the vehicle speed exceeds a certain control permission vehicle speed and then falls below a certain reference vehicle speed, whether the brake pedal is depressed, whether the coolant temperature and battery voltage are sufficiently high, or depending on the air conditioner or electrical equipment The success or failure of each condition such as whether the load is not large or whether the hood or the driver's door is open is determined. If it is determined that all of these conditions are satisfied, the fuel injection from the injector 11 and the spark ignition by the spark plug 12 are stopped, and the internal combustion engine is stopped.

  Then, after the idle stop condition is satisfied, the internal combustion engine is restarted when a predetermined idle stop end condition is satisfied. The ECU 0 is one in which the driver takes his foot off the brake pedal, the brake pedal is depressed more strongly, the accelerator pedal is depressed, a predetermined time (for example, 3 minutes) has elapsed in the idle stop state, etc. In any case, it is determined that the condition for ending the idle stop is satisfied, and a restart process for restarting fuel injection and ignition while performing cranking of the internal combustion engine is performed.

  Therefore, in this embodiment, a plurality of sets of the control permission vehicle speed and the reference vehicle speed are set for the purpose of increasing the idle stop opportunity and extending the idle stop period.

In the relatively high speed region, the control-permitted vehicle speed V _{H1 is set} to 13.5 km / h, for example, and the reference vehicle speed V _{H2 is set} to 13 km / h, for example. The control-permitted vehicle speed V _H1 is higher than the reference vehicle speed V _H2 . As shown in FIG. 2, the ECU 0 determines whether or not another idle stop condition is satisfied at a time point t _H when the vehicle speed increases beyond the control permission vehicle speed V _H1 and then decreases to the reference vehicle speed V _H2 . If the condition is satisfied, the idle stop is started.

In the relatively low speed region, the control-permitted vehicle speed V _{L1 is set} to 9.5 km / h, for example, and the reference vehicle speed V _{L2 is set} to 7 km / h, for example. The control-permitted vehicle speed V _L1 is higher than the reference vehicle speed V _L2 . As shown in FIG. 2, the ECU 0 determines whether or not other idle stop conditions are satisfied at a time point t _L when the vehicle speed increases beyond the control permission vehicle speed V _L1 and then decreases to the reference vehicle speed V _L2 . If the condition is satisfied, the idle stop is started.

In the present embodiment, the reference vehicle speed V _H2 on the high speed side is higher than the control start vehicle speed V _L1 on the low speed side. On top of that, in the present embodiment, the difference between the control permission speed V _L1 and the reference vehicle speed V _L2 slow side _{(V L1 -V L2 = 2.5km /} h), the control permission vehicle speed V _H1 and the reference high-speed side It is larger than the difference from the vehicle speed V _H2 (V _H1 −V _H2 = 0.5 km / h).

As a result, when the driver is driving the vehicle at a relatively low speed while repeatedly depressing or releasing the accelerator pedal in a situation where the road is congested or congested, the "vehicle speed is the control permitted vehicle speed V The condition of “decrease to the reference vehicle speed V _L2 after exceeding _L1 ” becomes difficult to be satisfied. Therefore, it is avoided that the idle stop is unexpectedly started during the low-speed traveling and the drivability is deteriorated.

On the other hand, since the difference (V _H1 −V _H2 ) between the control-permitted vehicle speed V _H1 and the reference vehicle speed V _H2 on the high speed side is set small, it accelerates to a relatively high vehicle speed, that is, about 13 km / h. In such a situation, the condition that “the vehicle speed drops to the reference vehicle speed V _H2 after exceeding the control permission vehicle speed V _H1 ” is easily established. As a result, the opportunity to execute idle stop when the idle stop condition is satisfied increases.

The present invention is not limited to the embodiment described in detail above. For example, in the above-described embodiment, V _H2 > V _L1 , but it does not prevent setting these so that V _H2 ≦ V _L1 .

  The contents of the idle stop conditions other than the vehicle speed are not limited to those in the above embodiment, and can be changed as appropriate. Similarly, the content of the idle stop end condition may be changed as appropriate.

  Other specific configurations of each part can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to control of an internal combustion engine mounted on a vehicle.

0 ... Control unit (ECU)
a ... vehicle speed signal V _H1 ... reference vehicle speed in the region of the control permission speed V _L2 ... lower speed in the region of the reference vehicle speed V _L1 ... lower speed in the region of the control permission speed V _H2 ... high speed side in the high-speed side region

Claims (1)

After the vehicle speed exceeds the control permission vehicle speed, the rotation of the internal combustion engine is stopped when an idle stop condition including one of the conditions that the vehicle speed falls below the reference vehicle speed is satisfied, and then a predetermined idle stop termination condition is established. Sometimes controls to restart the internal combustion engine,
A plurality of sets of the control permission vehicle speed and the reference vehicle speed are set,
Regarding the control permission vehicle speed V _H1 and the reference vehicle speed V _{H2 in} the relatively high speed region, and the control permission vehicle speed V _L1 and the reference vehicle speed V _L2 in the relatively low speed region, (V _H1 −V _H2 ) <(V _L1 − A control apparatus for an internal combustion engine, wherein the relationship of V _L2 ) is established.

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