JP4002230B2 - Internal combustion engine control device - Google Patents

Description

  The present invention relates to an internal combustion engine control apparatus capable of purifying exhaust gas and improving operating performance while reducing pumping loss and fuel consumption of the internal combustion engine.

  Control the amount of intake air in an internal combustion engine for a vehicle by detecting the amount of operation of the accelerator pedal operated by the driver with an accelerator sensor and electrically controlling the throttle opening based on the output of the accelerator sensor to control the amount of intake air Electronic throttle control (hereinafter referred to as ETV) is used. For example, when the driver increases the amount of operation of the accelerator pedal during acceleration of the vehicle, the air intake ratio fluctuates as the intake air amount fluctuation is asynchronous with the intake stroke of the internal combustion engine in the mechanical intake air amount control means. However, in ETV, since the throttle opening is electronically controlled by the intake air amount control means to change the cross-sectional area of the intake passage, the intake air amount can be controlled in synchronization with the stroke of the internal combustion engine, In addition to improving fluctuations in the air-fuel ratio, the required air amount is calculated to control the cross-sectional area of the intake passage, so that the air amount can be accurately controlled.

  Further, in such an ETV, there is a technique disclosed in Patent Document 1 as a technique for accurately controlling the intake air amount in a transient state such as during acceleration or deceleration of an internal combustion engine. The technology disclosed in this publication sets a throttle opening command value based on the accelerator operation amount, delays the output timing of this command value for a predetermined time, and opens the throttle opening based on the opening command value before the delay. Predicting the amount of change in the degree, and adding this predicted value to the current throttle opening to obtain the predicted throttle opening, predicting the amount of intake air during the intake stroke. Air-fuel ratio control can be performed.

JP 2002-201998 A (pages 8-14, FIGS. 2-19)

  However, the accelerator operation by the driver, that is, the request for changing the vehicle speed is not uniform, and various requests are generated depending on the driving conditions. For example, the request for changing the vehicle speed is not only a state in which the operation from the predetermined vehicle speed to the acceleration side or the deceleration side of the throttle opening continues for a certain period of time, but also the acceleration / deceleration state or the change of the acceleration / deceleration itself There are also operations that change variously within a short time. In such a case, it is difficult to predict the driver's will, and the air-fuel ratio cannot be accurately predicted and controlled. That is, only the amount of operation of the accelerator pedal operated by the driver is input as information, and the ETV is controlled based on this information. Therefore, for example, by changing the ETV operation with respect to the operation of the accelerator, the fluctuation of the air-fuel ratio Must be suppressed, and responsiveness is also delayed.

  Further, in the conventional general configuration in which the ETV is provided in the collecting portion of the intake pipe, the volume of the intake passage existing on the downstream side of the ETV is large with respect to the change in the effective area of the intake passage (opening and closing of the throttle valve). Since this acts as a first-order lag component, the change in the intake air amount sucked into the cylinder causes a delay with respect to the driver's operation, and the delay in the command value of the throttle opening causes a further delay. The accompanying delay in the output change of the internal combustion engine not only makes the driver uncomfortable, but also leaves a problem in safety.

  Generally, the driving state of the vehicle has a very high degree of freedom, and the amount of depression of the accelerator pedal may change during the fuel injection period after the fuel injection valve starts fuel injection. In the conventional ETV, the amount of depression of the accelerator pedal is controlled so that the throttle opening is changed regardless of the amount of intake air until then, and the air-fuel ratio is greatly deteriorated. In order to prevent this in the conventional apparatus, correction is performed by performing asynchronous injection during acceleration or the like. However, in such a method, there are cases where sufficient correction cannot be made in terms of quantity and timing, and when rapid acceleration / deceleration is performed immediately after the completion of fuel injection, the fuel injection amount cannot be changed. Therefore, the correction cannot be made, and particularly in the low rotational speed region, the air-fuel ratio becomes excessively rich or excessively lean, and exhaust gas deteriorates due to incomplete combustion and drivability is poor.

  The present invention has been made to solve such a problem, and an individual intake air amount control means (ETV) is arranged in each independent intake pipe distributed for each cylinder of each cylinder so that each ETV can independently In addition to controlling the intake air amount of the cylinder, the change in the throttle opening is restricted so that the intake air amount does not change in response to the accelerator operation during a period when the fuel injection means cannot correct the injection amount.

  An internal combustion engine control apparatus according to the present invention includes an independent intake pipe that supplies intake air to a plurality of cylinders for each cylinder, and an individual intake air amount control that individually controls an effective intake passage cross-sectional area provided for each cylinder. Means, a fuel injection valve provided in an independent intake pipe for supplying fuel for each cylinder, and calculating the intake air amount for a plurality of cylinders for each cylinder and controlling the individual intake air amount control means, and individually supplying the fuel supply amount for each cylinder And a control means for controlling the fuel injection valve to calculate the effective intake during a predetermined period when the fuel supply amount cannot be corrected during the transient operation of the internal combustion engine in which the accelerator operation is performed. The change of the passage cross-sectional area is restricted.

  According to the internal combustion engine control apparatus of the present invention, the individual intake air amount control means for individually controlling the effective intake passage cross-sectional area for each cylinder is provided in the independent intake pipe that supplies the intake air for each cylinder to a plurality of cylinders. This reduces the pumping loss and increases the responsiveness of the intake air. Also, during the transient operation of the internal combustion engine, the change of the effective intake passage cross-sectional area is restricted during the period when the fuel supply amount cannot be corrected. Thus, the output response of the internal combustion engine with respect to the accelerator operation can be improved while improving the exhaust gas purification performance, and an internal combustion engine control apparatus with excellent fuel efficiency can be obtained.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of an intake / exhaust passage of an internal combustion engine, and shows a schematic configuration of an internal combustion engine control apparatus according to Embodiment 1 of the present invention. FIGS. 2 and 3 are embodiments of the present invention. 2 is an explanatory diagram for explaining the operation of the internal combustion engine control device according to FIG. In FIG. 1, the internal combustion engine 1 is, for example, a case of four cylinders, and has four cylinders 1a to 1d. An intake pipe 2 for supplying intake air to each cylinder 1a to 1d forms an intake pipe assembly portion 4 having an air cleaner 3 at an upstream portion thereof, and each cylinder 1a to 1d is independently distributed from the intake pipe assembly portion 4. An intake pipe 5a to 5d is provided for each cylinder, and an intake valve 6a to 6d is provided in each cylinder 1a to 1d at a joint portion between each cylinder 1a to 1d and the independent intake pipe 5a to 5d.

  Each of the independent intake pipes 5a to 5d has a fuel injection valve 7a to 7d for supplying fuel to each cylinder from the downstream side, an intake pressure sensor 8a to 8d for detecting the intake air amount for each cylinder, and an accelerator pedal (not shown). There are provided ETVs 9a to 9d in which the throttle opening is controlled for each cylinder based on the operation amount. The ETVs 9a to 9d individually control the effective intake passage cross-sectional area for each cylinder as individual intake air amount control means. Each cylinder 1a to 1d is connected to an exhaust pipe 11 via exhaust valves 10a to 10d, and an air-fuel ratio sensor 12 for detecting the air-fuel ratio of the internal combustion engine 1 is provided at a collecting portion of the exhaust pipe 11. Yes. The internal combustion engine 1 is provided with a cylinder identification sensor 13 that discriminates the intake stroke of each cylinder and detects the rotational speed of the internal combustion engine 1.

  The control means 14 inputs the rotational speed of the internal combustion engine 1 from the cylinder identification sensor 13 to calculate the ignition timing, controls an ignition system (not shown), and manipulates an accelerator pedal (not shown) and intake pressure sensors 8a to 8d. Based on the output, the intake air amount is calculated for each cylinder, and the throttle openings of the ETVs 9a to 9d are controlled based on the calculated intake air amount for each cylinder and the cylinder discrimination signal output from the cylinder identification sensor 13. Further, the control means 14 calculates an appropriate fuel supply amount for each cylinder 1a to 1d from the intake amount for each cylinder and the output of the cylinder identification sensor 13, and controls the fuel injection valves 7a to 7d.

  The intake air distributed to the independent intake pipes 5a to 5d via the air cleaner 3 is controlled by the ETVs 9a to 9d. Therefore, the intake amount of each cylinder 1a to 1d can be detected from the intake pressure and the rotational speed detected by the intake pressure sensors 8a to 8d. The control of the intake air amount and the fuel injection amount by the control means 14 is feedback control that receives the output of the air-fuel ratio sensor 12 provided in the collecting portion of the exhaust pipe 11, and thereby the air-fuel ratio is controlled with high accuracy. . The control of the ignition system (not shown) by the control means 14 is controlled so as to perform ignition in the MBT or in the vicinity of the MBT corresponding to the environment of the internal combustion engine 1.

  When the accelerator operation is performed in the internal combustion engine control apparatus configured and operated as described above and the internal combustion engine 1 is operated in a transient state of acceleration or deceleration, a change in the throttle opening due to the accelerator operation, that is, a change in the intake air amount. On the other hand, a cylinder appears in which the fuel supply amount cannot be controlled by the control means 14 in terms of time. For example, when the accelerator operation is performed immediately after the calculation of the fuel injection amount is completed, it is impossible to correct the fuel injection amount appropriately for the change in the intake air amount until the next calculation of the fuel injection amount, and the air-fuel ratio becomes It will get worse. In such a case, the control means 14 controls the ETVs 9a to 9d during the period in which the fuel supply amount cannot be corrected, prohibits changes in the throttle opening, and after the period during which the fuel supply amount can be controlled. By controlling the throttle opening, exhaust gas deterioration due to changes in the air-fuel ratio is prevented.

  The contents of this control are shown in the operation explanatory diagrams of FIGS. 2 and 3, and the control contents which are the features of this invention will be described below. First, FIG. 2 shows the movement of the accelerator pedal at the time of deceleration and the operation of the intake system of the first cylinder and the third cylinder, and shows the control operation of the ETV at the time of deceleration. . Taking the first cylinder as an example, as shown in the drawing, fuel injection is performed on the upstream side of the intake valve in the independent intake pipe, and this fuel injection is performed during a period in which the intake valve is open. For example, when the operation amount of the accelerator pedal is decreased, the throttle opening of the ETV is decreased by the output of the accelerator sensor and the intake flow rate is decreased, but the fuel injection is started and the ETV throttle is decreased. The opening degree stops changing and the intake flow rate is kept constant.

  The change stop period of the throttle opening continues until the intake valve of the cylinder is closed, the change stop is released after the intake valve is closed, and the intake amount is based on the operation amount of the accelerator pedal until the next fuel injection starts. Controlled to change. This control is the same for the other cylinders. With this control, the intake flow rate during the period from the start of fuel injection to the closing of the intake valve is maintained at a constant value, and the control means 14 has the intake pressure sensor corresponding to the cylinder among the intake pressure sensors 8a to 8d. From the detected intake pressure of the target cylinder and the rotational speed detected by the cylinder identification sensor 13, the intake air filling amount for the target cylinder is calculated by the fuel injection period, and the fuel injection amount is determined based on this intake air filling amount. Perform fuel injection.

  Next, the operation when the accelerator operation changes during the fuel injection period will be described. FIG. 3 illustrates the ETV control operation when the accelerator operation is performed during the fuel injection period so that the internal combustion engine 1 accelerates rapidly from the deceleration state. For convenience, the first cylinder, the third cylinder, 4 cylinders are shown. As shown in the figure, when the accelerator operation changes during the fuel injection period of the third cylinder, the change in the throttle opening of the ETV is prohibited during the period from the start of fuel injection to the closing of the intake valve when the accelerator operation is in transition. Therefore, the value of the intake air amount for the third cylinder continues until just before the start of fuel injection.

  Assuming that the ignition sequence of the internal combustion engine 1 is in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder as shown in FIG. 3, the fourth cylinder, which is the next intake stroke of the third cylinder, is operated as an accelerator. The throttle opening changes following the accelerator operation without delay, and the subsequent second cylinder (not shown) and the first cylinder also change the throttle opening following the accelerator operation. Naturally, after the intake valve is closed, the third cylinder also follows the accelerator operation and the throttle opening changes. For the cylinders controlled so that the intake air amount increases, the fuel injection amount also changes corresponding to the increase of the intake air amount. Therefore, sufficient acceleration / deceleration response to the accelerator operation is ensured.

  The throttle opening change prohibition period described above, including the intake valve overlap period, must not cause a change in the amount of intake air charged in each cylinder, and the throttle opening change prohibition period is set in this way. . Also, the release of the throttle opening change prohibition period is set as the timing when the intake valve is substantially closed in order to improve the follow-up response to the operation of the accelerator pedal. Further, the start of the throttle opening change prohibition period may be immediately after the fuel injection amount calculation by the control means 14.

  As described above, when the ETV is provided in the independent intake pipe of the internal combustion engine, the interference of the intake air between the cylinders is eliminated, so that the pumping loss is reduced in the low load region, the fuel consumption is improved, and the throttle valve downstream It is known that the responsiveness of the intake is improved because the volume of the intake air is reduced. In the present invention, however, the ETV provided in the independent intake pipe can be individually controlled to change the speed of the accelerator operation. When the fuel injection has been completed, the intake passage area is changed following the accelerator operation for the cylinders for which fuel injection has already been completed, and the intake air amount before fuel injection is maintained for the cylinders during fuel injection until the intake is completed. As a result, proper combustion is performed to prevent the exhaust gas from deteriorating, and an output of the internal combustion engine having good responsiveness to the operation of the driver can be obtained.

  The internal combustion engine control apparatus according to the present invention can be applied to an electric ignition type internal combustion engine for a vehicle, a marine internal combustion engine, and the like.

1 is a schematic configuration illustrating an internal combustion engine control apparatus according to Embodiment 1 of the present invention. It is explanatory drawing explaining operation | movement of the internal combustion engine control apparatus by Embodiment 1 of this invention. It is explanatory drawing explaining operation | movement of the internal combustion engine control apparatus by Embodiment 1 of this invention.

Explanation of symbols

1 internal combustion engine, 1a to 1d cylinder, 2 intake pipe, 3 air cleaner,
4 intake pipe assembly, 5a to 5d independent intake pipe, 6a to 6d intake valve,
7a-7d fuel injection valve, 8a-8d intake pressure sensor,
9a to 9d ETV (individual intake air amount control means),
10a to 10d exhaust valve, 11 exhaust pipe, 12 air-fuel ratio sensor,
13 cylinder identification sensor, 14 control means.

Claims (2)

An independent intake pipe for supplying intake air to a plurality of cylinders for each cylinder, an individual intake air amount control means for individually controlling an effective intake passage sectional area for each cylinder provided in the independent intake pipe, and a cylinder provided in the independent intake pipe A fuel injection valve that supplies fuel separately, and calculates the intake air amount for a plurality of cylinders for each cylinder to control the individual intake air amount control means, and individually calculates the fuel supply amount for each cylinder to control the fuel injection valve And the control means makes it impossible to correct the fuel supply amount during transient operation of the internal combustion engine in which the accelerator operation is performed. After the calculation of the fuel supply amount is completed, the intake air in the cylinder period until the valve is substantially closed, the effective intake passage to restrict the change of the cross-sectional area, the internal combustion engine control instrumentation, characterized in that to release the change restriction of the effective intake cross-sectional area substantially closed when the intake valve . An independent intake pipe for supplying intake air to a plurality of cylinders for each cylinder, an individual intake air amount control means for individually controlling an effective intake passage sectional area for each cylinder provided in the independent intake pipe, and a cylinder provided in the independent intake pipe A fuel injection valve that supplies fuel separately, and calculates the intake air amount for a plurality of cylinders for each cylinder to control the individual intake air amount control means, and individually calculates the fuel supply amount for each cylinder to control the fuel injection valve And the control means makes it impossible to correct the fuel supply amount during transient operation of the internal combustion engine in which the accelerator operation is performed, and the intake valve in the cylinder from the start of fuel injection by the fuel injection valve internal combustion engine system but substantially closing time to the to limit the change of the effective intake cross-sectional area, and cancels the change restriction of the effective intake cross-sectional area substantially closed when the intake valve Apparatus.

Images