JP2008297903A - Internal combustion engine control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To resolve the following problem: the transmission over a CAN of accelerator-opening information is delayed to cause a control delay in the vehicle control system wherein an ECU for effecting an accelerator-opening-control output for an economy-running control and another ECU mounted directly on an internal combustion engine to effect a fuel injection-quantity control are connected over the CAN. <P>SOLUTION: The internal combustion engine control system is constituted so that the accelerator-opening-control output by the ECU for effecting an accelerator-opening-control output conforms with the deviation of an actual fuel-flow rate corresponding to an actual accelerator opening from a desired fuel-flow rate corresponding to a desired accelerator opening for the economy-running control, and if the actual fuel-flow rate exceeds the desired rate, the control output is effected at a desired value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to fuel injection control of an internal combustion engine. The present invention is used for fuel injection amount control in an economical fuel-saving driving state called eco-run. The present invention corresponds to the fuel injection amount that is actually given to the internal combustion engine in order to achieve an economical fuel-saving driving state based on information on the accelerator operation amount (hereinafter referred to as the actual accelerator opening) operated by the operator. The present invention relates to a control technique for generating an accelerator control output and supplying it to a control circuit of an internal combustion engine. The present invention is an apparatus developed for implementation in a vehicle equipped with a diesel engine, but can be widely implemented in engines using liquid fuel.

  An engine control technique called eco-run control is known. In this control technology, as an example, in order to reduce fuel consumption, the engine fuel injection is controlled with the fuel injection amount reduced, instead of outputting the output torque according to the engine standard corresponding to the accelerator operation amount. Alternatively, control is performed so that the fuel injection amount is reduced so as not to exhibit acceleration corresponding to the accelerator operation amount.

  As such a control technique, in order to prevent the fuel consumption from being increased by excessively operating the accelerator, the fuel supply amount given to the engine is not given as the actual accelerator opening information, but according to the vehicle speed. Calculate the target accelerator opening so as to reduce the amount of fuel injection and reduce the fuel injection amount, and compare it with the target accelerator opening threshold. If the actual accelerator opening is larger than the target accelerator opening, the target accelerator opening When the value is the accelerator opening control output and is smaller than the target accelerator opening value, a technique for controlling the fuel injection amount of the engine using the actual accelerator opening as the accelerator opening control output has been proposed (Patent Document 1 or 2).

  This technology uses a single ECU to perform fuel injection control for an engine with low acceleration or torque corresponding to the vehicle speed and gear position at that time, based on the information on the actual accelerator opening, vehicle speed, and gear position that are input. Is what you do.

JP 2004-50904 A JP 2005-133671 A

  The technique of the above-mentioned patent document 1 or 2 compares the target accelerator opening value calculated for each cycle by one ECU with the actual accelerator opening, and determines the accelerator control output to be given to the engine based on the magnitude relationship. Was.

By the way, due to an increase in vehicle control items and electrical parts in recent years, CAN (Controller
It has been attempted to perform vehicle control using an area network, and vehicle control has been performed by transmitting vehicle information such as vehicle speed information and accelerator information between distributed ECUs using CAN.

  This CAN is a time division transmission line, and transmits data for vehicle control in a time division manner, and its transmission frequency is determined by the data to be transmitted.

  Information such as an accelerator operation, a brake operation, and a steering operation, which are information on a driving operation for controlling the vehicle, is generated around the cabin where the driver's seat is located. For this reason, the ECU of the control system related to the operation control for performing the eco-run control based on the information on the accelerator operation amount and the speed change operation is placed in the vicinity of the cabin, and the control output as a result of the determination is CAN, and various controls are performed. If it is transmitted to each control circuit to be performed, the amount of harness can be reduced.

  In addition, a general-purpose engine control ECU is provided for fuel injection control in the engine. Therefore, accelerator control when performing eco-run operation control is used from the ECU for operation control to the engine control ECU. The fuel injection control may be performed by giving an accelerator control output via CAN.

  However, since CAN is a time division transmission line, its transmission speed (occupied band in CAN) is determined by data. Therefore, when the accelerator control information transmitted by the CAN connecting the two ECUs is later than the control cycle of the engine control ECU, there is a problem that a control delay occurs. This control delay causes a time delay between the timing of determination comparing the actual accelerator opening and the target accelerator opening value and the actual control. Overshoot and undershoot are used for fuel injection control. The problem that becomes easy to occur occurs.

  If the CAN transmission speed is further increased so that there is no time delay between the operation control ECU and the engine control ECU, such a problem can be solved, but the CAN transmission speed is further increased. This is due to standardization problems, and high-speed components must be used, so that the transmission system itself becomes expensive. This also increases the vehicle price.

  The present invention solves such a problem. When eco-run control is performed in cooperation with two ECUs using CAN, fuel injection control is performed even when the CAN transmission speed is low. An object of the present invention is to provide an internal combustion engine control device capable of highly accurate control.

  The present invention takes in information of the actual accelerator opening and the vehicle speed, and calculates a target accelerator opening that realizes an economical driving state with reduced fuel consumption based on the information of the actual accelerator opening and the vehicle speed; Accelerator control of an internal combustion engine by comparing an actual fuel flow rate (hereinafter referred to as an actual flow rate) according to the actual accelerator opening and a target fuel flow rate (hereinafter referred to as a target flow rate) according to the target accelerator opening. An eco-run control circuit including an output means, and an internal-combustion engine control circuit for controlling a fuel injection amount to the internal combustion engine based on the accelerator control output, the eco-run control circuit and the internal-combustion engine control circuit being The means for performing the accelerator control output that is connected via a divided communication path calculates a deviation between the actual flow rate and the target flow rate, and outputs an accelerator opening control output corresponding to the deviation amount. Including means for forming an internal combustion engine control apparatus according to claim.

  According to the present invention, precise eco-run control can be performed based on the deviation between the actual flow rate and the target flow rate. In addition, even when vehicle control information is transmitted in a time-sharing manner using CAN, precise eco-run control can be performed without causing a control delay. Further, by using CAN, the harness of the entire vehicle can be reduced, and the weight of the vehicle and the cost of the vehicle can be reduced.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 and FIG. 2 are overall configuration diagrams of the internal combustion engine control apparatus of the present embodiment, FIG. 1 shows an in-vehicle situation, and FIG. 2 shows a connection situation by CAN.

  In general, the internal combustion engine control device has various functions such as an automatic speed control function and an auxiliary brake control function such as an auto cruise and a speed limiter in addition to the eco-run control function which is the object of the present invention. In the description of the internal combustion engine control device of the present embodiment, the description will be limited to the eco-run control function.

  As shown in FIG. 1, the internal combustion engine control apparatus according to the present embodiment includes an eco-run control circuit 1 provided in the vehicle control ECU 10 and an internal combustion engine control circuit 2 provided in the engine ECU 20. As shown in FIG. 2, the eco-run control circuit 1 and the internal combustion engine control circuit 2 are connected by CAN. In addition, illustration of the apparatus for implement | achieving CAN was abbreviate | omitted.

  That is, the internal combustion engine control apparatus of the present embodiment takes in the information of the actual accelerator opening and the vehicle speed, and realizes an economical traveling state in which fuel consumption is reduced based on the information of the actual accelerator opening and the vehicle speed. A target accelerator opening calculation unit 3 that calculates the opening, and an accelerator opening that compares the actual flow rate according to the actual accelerator opening with the target flow rate according to the target accelerator opening and outputs the accelerator control output of the internal combustion engine. An eco-run control circuit 1 including a degree control output generation unit 4 and an internal combustion engine control circuit 2 for controlling a fuel injection amount to the internal combustion engine based on the accelerator control output, the eco-run control circuit 1 and the internal combustion engine control circuit 2 is connected via a CAN time-division communication path, and the accelerator opening control output generation unit 4 calculates a deviation between the actual flow rate and the target flow rate, and adjusts the amount corresponding to the deviation amount. And generating a cell opening control output.

  For example, the target accelerator opening calculation unit 3 calculates a target accelerator opening that keeps the vehicle speed constant even when the driver frequently operates the accelerator during high-speed traveling in the top gear. At each gear position other than the top gear, the target accelerator opening is calculated so that the acceleration does not exceed a predetermined upper limit value at each gear position. That is, the driving state desired by the driver is estimated from the driver's accelerator operation state and the gear position, and the target accelerator opening that can realize the driving state desired by the driver is calculated while suppressing fuel consumption.

  Next, the accelerator opening control output generation procedure will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing the accelerator opening control output generation procedure of this embodiment. FIG. 4 is a diagram showing a target accelerator opening calculation map of the present embodiment, where the horizontal axis represents deviation and the vertical axis represents target accelerator opening (%).

  In the map of FIG. 4, when the deviation value is equal to or less than a negative (−) predetermined value (−a), a conservative target accelerator opening is set. In other words, in such a situation, the vehicle is still running at a low speed and the driver has not depressed the accelerator pedal greatly. Therefore, the target accelerator opening is preferably conservative. When the deviation value is equal to or greater than a positive (+) predetermined value (+ b), the target accelerator opening is uniformly set to -40%. This is to prevent the accelerator pedal opening from exceeding a predetermined accelerator opening even when the accelerator pedal is fully depressed.

  As shown in FIG. 3, the target accelerator opening calculation unit 3 acquires information on the actual accelerator opening and the vehicle speed (S1), and calculates the target accelerator opening (S2). Information on the target accelerator opening is transmitted to the accelerator opening control output generator 4.

  Next, the accelerator opening control output generator 4 calculates a target flow rate corresponding to the target accelerator opening (S3). For this calculation, for example, a target flow rate calculation map showing the relationship between the target flow rate and the target accelerator opening is used. Subsequently, the actual flow rate information is acquired from the internal combustion engine control circuit 2 by CAN (every 100 ms) (S4), and the deviation is calculated by subtracting the target flow rate from the actual flow rate (S5). Then, the target accelerator opening corresponding to the calculated deviation is calculated using the target accelerator opening calculation map shown in FIG. 4 (S6). Subsequently, the calculated target accelerator opening is compared with the actual accelerator opening (S7). When the target accelerator opening is the actual accelerator opening (S8), the accelerator opening increase (S9) is determined as the internal combustion engine control circuit 2. (Accelerator opening control output transmission) (S11). When the target accelerator opening is less than the actual accelerator opening (S8), the internal combustion engine control circuit 2 is instructed to reduce the accelerator opening (S10) (S11).

(Explanation of effect)
The effects of the present invention will be described with reference to examples. FIG. 5 shows the conventional control performed every 16 ms, the control when the same control as every 16 ms performed conventionally is performed every 100 ms, and the control according to the present invention. It is a figure which compares. The example of FIG. 5 shows a representative example that remarkably represents the effect of the present invention among many experimental results conducted by the applicant of the present application. FIG. 6 is an overall configuration diagram of a conventional internal combustion engine control device. FIG. 7 is a flowchart showing a conventional control procedure every 16 ms.

  As shown in FIG. 6, the conventional internal combustion engine control apparatus includes an eco-run control circuit 11 and an internal combustion engine control circuit 12 in one engine ECU 21, and can exchange information with each other every 16 ms. Control can be performed every 16 ms.

  As shown in FIG. 7, the control procedure acquires actual flow rate information every 16 ms (S20), and when the actual flow rate is equal to or higher than the target flow rate (S21), the accelerator opening is decreased with a slope of 40% per second. (S22). When the actual flow rate is less than the target flow rate (S21), the accelerator opening is increased with a slope of 20% per second (S23).

  The state of accelerator opening control when the control performed every 16 ms that has been conventionally performed is used is shown by a solid line at the bottom of FIG. In addition, the state of the accelerator opening control when the same control as the control performed every 16 ms that is conventionally performed is performed in 100 ms is indicated by a two-dot chain line.

  The second row of FIG. 5 shows the determination results every 100 ms. The third row in FIG. 5 shows the determination results every 16 ms. When these determination results are compared, there are many portions where the determination results are reversed with each other, and it is not appropriate to follow the conventional control every 16 ms as it is and perform it every 100 ms.

  In the control of the present invention, as shown in the fourth stage of FIG. 5, the deviation between the actual flow rate and the target flow rate is calculated every 100 ms, and the accelerator opening degree control is performed using the calculation result. This is shown by a one-dot chain line at the bottom of FIG.

  The object of the present invention is to replace the control approximated to the conventional control every 16 ms by the control every 100 ms. In order to quantify the degree of achievement of this object, the accelerator opening control (two-dot chain line) when the same control as the conventional control every 16 ms is performed every 100 ms, and the control of the present invention (one point) The distance on the graph from the accelerator opening control (solid line) by the control performed every 16 ms, which has been conventionally performed, was measured for each of the chain lines), and the average value of the distances was calculated.

  The distance A shown in FIG. 5 is the conventional control for every 16 ms of the accelerator opening control (two-dot chain line) when the same control as the conventional control for every 16 ms is performed every 100 ms. Is a numerical value obtained by measuring the distance from the accelerator opening control (solid line) by 32 times at equal intervals, and the distance B is the accelerator opening by the control of the present invention (dotted line) every 16 ms. It is the numerical value which measured the distance from control (solid line) 32 times at equal intervals. The total distance A was “−28”, and the total distance B was “10.5”. When these average values are calculated, the distance A becomes “−0.9”, the distance B becomes “0.3”, and the control (one-dot chain line) of the present invention is the control performed every 16 ms (conventional control). It can be seen that it is closer to the solid line.

  Although the description in this specification is omitted, the control of the present invention is also performed every 16 ms, which has been conventionally controlled from the results of experiments conducted by the applicant of the present invention by mounting the internal combustion engine control device of the present invention on a vehicle. What can be substituted is supported.

  According to the present invention, since the eco-run control can be performed by using CAN, the harness of the entire vehicle can be reduced, and the vehicle can be used for weight reduction and vehicle cost reduction.

1 is an overall configuration diagram of an internal combustion engine control device according to an embodiment (in-vehicle situation). 1 is an overall configuration diagram of an internal combustion engine control device according to the present embodiment (connection status by CAN communication). FIG. The flowchart which shows the throttle opening control output production | generation procedure of a present Example. The figure which shows the target accelerator opening calculation map of a present Example. Compare the behavior of the conventional control every 16 ms, the control when the same control as the conventional 16 ms control is performed every 100 ms, and the control of the present invention. Figure. The whole internal combustion engine control apparatus block diagram. The flowchart which shows the procedure of the control for every 16 ms conventionally performed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11 Eco-run control circuit 2, 12 Internal combustion engine control circuit 3 Target accelerator opening calculating part 4 Accelerator opening control output generation part 10 Vehicle control ECU
20, 21 Engine ECU

Claims (1)

Means for taking in information on an accelerator pedal operation amount and vehicle speed, and calculating a target accelerator opening for realizing an economical driving state with reduced fuel consumption based on the information on the operation amount of the accelerator pedal and vehicle speed;
An eco-run control circuit including means for comparing an actual fuel flow rate according to an operation amount of the accelerator pedal and a target fuel flow rate according to the target accelerator opening, and performing an accelerator control output of the internal combustion engine;
An internal combustion engine control circuit for controlling a fuel injection amount to the internal combustion engine based on the accelerator control output,
The eco-run control circuit and the internal combustion engine control circuit are connected via a time division communication path,
The means for performing the accelerator control output includes means for calculating a deviation between the actual fuel flow rate and the target fuel flow rate, and generating an accelerator opening control output corresponding to the deviation amount. Internal combustion engine control device.

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