JP4670594B2 - Vehicle constant speed travel control device - Google Patents

Description

  The present invention relates to a constant speed travel control device for a vehicle that performs vehicle speed feedback control for matching a vehicle speed to a target value.

  2. Description of the Related Art Conventionally, a constant speed traveling technique that holds a traveling speed (vehicle speed) of a vehicle at a predetermined set speed according to a driver's instruction has been put into practical use. In the vehicle control device that performs this constant speed traveling, the vehicle speed is detected by a sensor or the like, and feedback control is performed so that the detected vehicle speed matches the set speed every time. At this time, for example, in the case of a diesel engine, the feedback control of the vehicle speed is performed by controlling the fuel injection amount, and in the case of the gasoline engine, the feedback control of the vehicle speed is performed by controlling the intake air amount accompanying the operation of the throttle opening (for example, , See Patent Document 1).

Here, it is conceivable that the traveling state of the vehicle changes during constant speed traveling, and the vehicle speed changes accordingly. For example, when a vehicle traveling on a flat road enters an uphill road or the vehicle turns at a corner portion of the road, the vehicle speed decreases accordingly. In such a case, in the existing constant speed traveling control device, there is a problem that it takes time to return to the original set speed after the vehicle speed once decreases, and the followability of the vehicle speed to the set speed is reduced. In particular, when there is a dead zone for feedback control based on the set speed during constant speed driving to suppress hunting for vehicle speed feedback control, a drop in vehicle speed, etc. has occurred depending on the road surface conditions, etc. At this time, the start of the vehicle speed feedback control may be delayed. Therefore, it takes time until the vehicle speed increases to the set speed.
Japanese Patent Laid-Open No. 7-300026

  The main object of the present invention is to provide a constant speed traveling control device for a vehicle that can suppress the deterioration of the followability of the vehicle speed when the traveling state of the vehicle changes during constant speed traveling.

  In the constant speed running control of the vehicle, in order to make the speed of the vehicle coincide with the target value, the actuator device equipped in the engine is operated and the vehicle speed feedback control is performed. The actuator device includes a fuel injection valve for injecting and supplying fuel to each cylinder of the engine, a throttle actuator for adjusting the amount of intake air sucked into each cylinder of the engine, and the like. Vehicle speed feedback control is performed by manipulating the injection amount and throttle opening.

Here, when the vehicle approaches a slope or the like while the vehicle is traveling at a constant speed, the load acting on the engine is increased or decreased, thereby decreasing or increasing the vehicle speed. In such a case, in the existing control device, there is a possibility that the followability of the vehicle speed with respect to the target value is lowered. In this regard, according to the present invention, the work amount of each cylinder of the engine is acquired when the vehicle is traveling at a constant speed, and the operation amount of the actuator device is appropriately corrected based on the acquired work amount of the engine. In addition, it is possible to suppress the deterioration of the followability of the vehicle speed.

In the second aspect of the present invention, since the dead zone region of the vehicle speed feedback control is set and the vehicle speed feedback control by the operation of the actuator device is not performed until the vehicle speed decreases or rises and exceeds the dead zone region, When the vehicle speed changes with time or the like, the follow-up of the vehicle speed becomes remarkable. On the other hand, the follow-up performance of the vehicle speed can be improved by correcting the operation amount of the actuator device based on the amount of work each time as described above.

In the invention of claim 3, the greater the difference between the amount of work each time and the reference value set with reference to when the vehicle is traveling on a flat road, the greater the correction amount for the operation amount of the actuator device. Even when the vehicle speed greatly changes with respect to the target value, it is possible to quickly return to the target value.

In the invention according to claim 4, the operation amount of the actuator device is not corrected if the difference between the work amount at each time and the reference value set based on the time when the vehicle is traveling on a flat road is less than a predetermined value. Control hunting can be suppressed.

  In the fifth aspect of the present invention, since the upper limit value is set as the correction amount for the operation amount of the actuator device, it is possible to suppress deterioration in drivability associated with excessive correction.

According to the sixth aspect of the present invention, when the operation amount of the actuator device is corrected based on the work amount when the vehicle is traveling at a constant speed, a correction restriction is applied at the beginning of the correction. Sudden acceleration, deceleration, etc. against the driver can be suppressed. This improves drivability. Here, the "correction limit", delaying the actual correction start, it is considered such as by modifying the correction amount (amount correction calculated on the basis of the amount of work) to a small value. Further, when correcting the correction amount to a small value, it is preferable to gradually increase the correction amount.

In the engine, the rotation increase due to combustion and the rotation decrease due to load are basically repeated, and at this time, the rotation speed changes reflecting the instantaneously generated torque. Here, in the invention according to claim 7, the rotational speed calculated by the rotational speed calculation means is filtered at a frequency set based on the combustion frequency of the engine to calculate an instantaneous torque equivalent value and the calculated value. The engine work is calculated based on the instantaneous torque equivalent value. In this case, since the rotational speed is filtered at a frequency based on the combustion frequency of the engine, a component of the combustion frequency is extracted from the rotational speed, and an instantaneous torque equivalent value is calculated so as to correspond to the combustion cycle. The engine work can be suitably obtained from the instantaneous torque equivalent value.

As a method of calculating the work load of the engine, as described in claim 8, the combustion of each cylinder with a constant interval integral of the instantaneous torque equivalent value for each cylinder, the inertial force, each of the workload or total by the load Is good to calculate.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. The present embodiment embodies the present invention as a common rail fuel injection system for a vehicle diesel engine, and a detailed configuration thereof will be described below.

  FIG. 1 is a configuration diagram showing an outline of a common rail fuel injection system. In FIG. 1, a multi-cylinder diesel engine (hereinafter referred to as an engine) 10 is provided with an electromagnetic injector 11 for each cylinder, and these injectors 11 are connected to a common rail (pressure accumulation pipe) 12 common to each cylinder. A high pressure pump 13 as a fuel supply pump is connected to the common rail 12, and high pressure fuel corresponding to the injection pressure is continuously accumulated in the common rail 12 as the high pressure pump 13 is driven. The high-pressure pump 13 is driven as the engine 10 rotates, and fuel is repeatedly sucked and discharged in synchronization with the engine rotation. The high pressure pump 13 is provided with an electromagnetically driven suction metering valve (SCV) 14 at its fuel suction portion, and the low pressure fuel pumped from the fuel tank 16 by the feed pump 15 passes through the suction metering valve 14. And sucked into the fuel chamber of the pump 13. In practice, the high-pressure pump 13, the suction metering valve 14, and the feed pump 15 are integrated into a pump unit.

  A common rail pressure sensor 17 is provided in the common rail 12, and the fuel pressure (common rail pressure) in the common rail 12 is detected by the common rail pressure sensor 17. Although not shown, the common rail 12 is provided with an electromagnetically driven (or mechanical) pressure reducing valve. When the common rail pressure rises excessively, the pressure reducing valve is opened to perform pressure reduction. It has become.

  A rotation speed sensor 19 for detecting the rotation speed of the crankshaft 18 is provided near the crankshaft 18 of the engine 10. The rotational speed sensor 19 is, for example, an electromagnetic pickup sensor that detects passage of teeth of a timing rotor provided integrally with the crankshaft 18, and a pulsed rotational speed is obtained by shaping the detection signal of the sensor 19. A signal (NE pulse) is generated. In the present embodiment, the NE pulse angular interval (angle between pulse rising edges) is 30 ° CA, and the rotation speed can be detected at a cycle of 30 ° CA.

  The ECU 20 is an electronic control unit that includes a known microcomputer including a CPU, ROM, RAM, EEPROM, and the like. The ECU 20 includes detection signals from the common rail pressure sensor 17 and the rotation speed sensor 19 and an accelerator operation amount by a driver. Detection signals are sequentially input from various sensors such as an accelerator opening sensor that detects the temperature of the engine, a water temperature sensor that detects the temperature of the engine coolant, and a fuel temperature sensor that detects the fuel temperature in the common rail 12. Then, the ECU 20 determines an optimal fuel injection amount and injection timing based on engine operation information such as the engine rotation speed and the accelerator opening, and outputs an injection control signal corresponding to the fuel injection amount to the injector 11. Thereby, the fuel injection from the injector 11 to the combustion chamber is controlled in each cylinder.

  Further, the ECU 20 calculates a target value of the common rail pressure (injection pressure) based on the engine speed and the fuel injection amount at that time, and the fuel discharge amount of the high-pressure pump 13 so that the actual common rail pressure becomes the target common rail pressure. Feedback control. Actually, the target discharge amount of the high-pressure pump 13 is determined based on the deviation between the target value and the actual value of the common rail pressure, and the opening degree of the suction metering valve 14 of the high-pressure pump 13 is controlled accordingly. At this time, by controlling the command current value for the electromagnetic solenoid of the intake metering valve 14, the opening degree of the intake metering valve 14 is increased and decreased, and the fuel discharge amount by the high-pressure pump 13 is adjusted accordingly.

  In addition, the present system has a cruise control function (constant speed traveling control function) for feedback control of the vehicle speed so as to follow an arbitrarily set target vehicle speed. A vehicle speed sensor 35 is connected. In addition to the cruise main switch (power switch), the cruise setting device 30 includes a vehicle speed set switch that sets the target vehicle speed, and a tap-down / tap-up function that reduces or increases the target vehicle speed step by step during the cruise control. A resume function or the like is provided for resetting the target vehicle speed to the previous target vehicle speed (memory vehicle speed). In addition, an inter-vehicle distance control function that keeps the inter-vehicle distance from the preceding vehicle constant may be provided.

  Various signals (cruise main signal, target vehicle speed set signal, tap down / tap up signal, etc.) are input from the cruise setting device 30 to the ECU 20 and a vehicle speed signal detected by the vehicle speed sensor 35 is input. When the target vehicle speed is set by the cruise setting device 30, the ECU 20 performs vehicle speed feedback control so that the vehicle speed matches the target vehicle speed. More specifically, regarding the vehicle speed feedback control, the ECU 20 corrects the fuel injection amount by the injector 11 based on the deviation between the actual vehicle speed and the target vehicle speed, and targets the actual vehicle speed by the torque change accompanying the increase or decrease in the fuel injection amount. I try to follow the vehicle speed. At this time, for the purpose of suppressing feedback control hunting, a control dead zone region is set based on the target vehicle speed. If the actual vehicle speed is within the dead zone region (for example, target speed ± 5 km / h), the vehicle speed feedback control ( The fuel injection amount increase or decrease correction based on the vehicle speed deviation is not performed.

  If the ECU 20 determines that the tap-down switch is turned on, the ECU 20 decreases the target vehicle speed by a predetermined vehicle speed stepwise. If the ECU 20 determines that the tap-up switch is turned on, the ECU 20 increases the target vehicle speed by a predetermined vehicle speed stepwise. . In addition, when the ECU 20 determines that the resume switch is turned on, the ECU 20 resets the previous target vehicle speed (stored vehicle speed) as the target vehicle speed.

  By the way, it is conceivable that when a vehicle travels on a slope (uphill or downhill) during cruise traveling, the vehicle speed decreases or rises due to the influence. Further, it is considered that the vehicle speed decreases due to the influence when the vehicle turns during cruise traveling. At this time, the conventional apparatus has a disadvantage that it takes time to return to the target vehicle speed when the vehicle speed once decreases or increases. Therefore, in this embodiment, when the vehicle speed decreases or increases according to the state of the vehicle traveling road surface or the like during the cruise traveling, attention is paid to the fact that the work amount of each cylinder of the engine 10 decreases or increases. The work amount for each cylinder is calculated based on the information, and the fuel injection amount is corrected based on the work amount for each cylinder, and the followability of the vehicle speed is improved by the correction.

  Specifically, as shown in FIG. 2, the engine rotational speed Ne is input to the filter means M1 as an input signal at a constant angular period, and only the rotational fluctuation component at each time point is extracted by the filter means M1 to instantaneously. A torque equivalent value Neflt is calculated. At this time, the engine rotational speed Ne is sampled at an NE pulse output cycle (30 ° CA in the present embodiment). The filter means M1 is composed of, for example, a BPF (band filter), and the high frequency component and the low frequency component included in the rotation speed signal are removed by the BPF. The instantaneous torque equivalent value Neflt (i), which is the output of the filter means M1, is expressed by the following equation (1), for example.

式（１）において、Ｎｅ（ｉ）は回転速度の今回サンプリング値、Ｎｅ（ｉ−２）は回転速度の２回前サンプリング値、Ｎｅｆｌｔ（ｉ−１）は瞬時トルク相当値の前回値、Ｎｅｆｌｔ（ｉ−２）は瞬時トルク相当値の前々回値である。ｋ１〜ｋ４は定数である。上記の式（１）により、回転速度信号がフィルタ手段Ｍ１に入力される都度、瞬時トルク相当値Ｎｅｆｌｔ（ｉ）が算出される。

In equation (1), Ne (i) is the current sampling value of the rotational speed, Ne (i-2) is the sampling value two times before the rotational speed, Neflt (i-1) is the previous value of the instantaneous torque equivalent value, Neflt. (I-2) is the value immediately before the instantaneous torque equivalent value. k1 to k4 are constants. By the above equation (1), the instantaneous torque equivalent value Neflt (i) is calculated every time the rotation speed signal is input to the filter means M1.

  The above equation (1) is a discretization of the transfer function G (s) represented by the following equation (2). Here, ζ is an attenuation coefficient, and ω is a response frequency.

本実施の形態では特に、応答周波数ωをエンジン１０の燃焼周波数としており、上記の式（１）ではω＝燃焼周波数としたことに基づいて定数ｋ１〜ｋ４が設定されている。燃焼周波数は単位角度ごとの燃焼頻度を表した角度周波数であり、４気筒エンジンの場合には燃焼周期（燃焼角度周期）が１８０°ＣＡであり、その燃焼周期の逆数により燃焼周波数が決定される。

Particularly in the present embodiment, the response frequency ω is the combustion frequency of the engine 10, and the constants k1 to k4 are set based on the fact that ω = combustion frequency in the above equation (1). The combustion frequency is an angular frequency representing the combustion frequency for each unit angle. In the case of a four-cylinder engine, the combustion cycle (combustion angle cycle) is 180 ° CA, and the combustion frequency is determined by the reciprocal of the combustion cycle. .

  In addition, the integrating means M2 in FIG. 2 takes in the instantaneous torque equivalent value Neflt and integrates the instantaneous torque equivalent value Neflt for a certain period for each combustion cycle of each cylinder, so that the work for each cylinder, which is the torque integrated value of each cylinder. The quantities Sneflt # 1 to Sneflt # 4 are calculated. At this time, NE pulses numbered from 0 to 23 are assigned to NE pulses output at a 30 ° CA cycle. In terms of the combustion order of each cylinder, the NE pulse number = 0-5 are assigned, the pulse number = 6-11 is assigned to the combustion cycle of the third cylinder, the NE pulse number = 12-17 is assigned to the combustion cycle of the fourth cylinder, and the combustion cycle of the second cylinder. Is assigned NE pulse number = 18-23. Then, cylinder-specific work amounts Sneflt # 1 to Sneflt # 4 are calculated for each of the first to fourth cylinders by the following equation (3).

なお以下の記載では、気筒番号を＃ｉと表し、気筒別仕事量Ｓｎｅｆｌｔ＃１〜Ｓｎｅｆｌｔ＃４を気筒別仕事量Ｓｎｅｆｌｔ＃ｉとも表記する。

In the following description, the cylinder number is expressed as #i, and the cylinder work Sneflt # 1 to Sneflt # 4 is also expressed as cylinder work Sneflt # i.

  FIG. 3 is a time chart showing transitions of the engine rotation speed Ne, the instantaneous torque equivalent value Neflt, and the cylinder work Sneflt # i. In FIG. 3, the instantaneous torque equivalent value Neflt swings up and down with respect to the reference level Ref, and the instantaneous work torque equivalent value Neflt is integrated within the combustion cycle for each cylinder to calculate the cylinder work Sneft # i. . At this time, the integral value of the instantaneous torque equivalent value Neflt on the positive side of the reference level Ref corresponds to the work amount due to combustion, and the integral value of the instantaneous torque equivalent value Neflt on the negative side of the reference level Ref is the work amount due to the load. It corresponds to. The reference level Ref is determined according to the average rotational speed through each cylinder.

  In the combustion cycle of each cylinder, the balance between the work due to combustion and the work due to load becomes zero, and the work per cylinder Sneflt # i becomes 0 (the work due to combustion−the work due to load = 0). When the vehicle approaches the slope during cruise traveling, the cylinder work amount Sneflt # i fluctuates to the positive side or the negative side due to the influence. For example, when the vehicle approaches an uphill road, the work amount due to the load exceeds the work amount due to combustion, so that the work amount by cylinder Sneflt # i increases to the negative side. Focusing on this point, the fuel injection amount is corrected based on the cylinder work Sneflt # i during cruise traveling.

  In this case, the larger the difference between the cylinder specific work amount Sneflt # i and the reference value of the cylinder specific work amount Sneflt # i set when the vehicle is traveling on a flat road, the larger the correction amount for the fuel injection amount is. To do. However, since the work amount Sneflt # i (reference value) for each cylinder when the vehicle travels on a flat road is set to 0, the correction amount for the fuel injection amount increases as the absolute value of the work amount for each cylinder Sneflt # i increases. To do.

  It should be noted that in the engine 10, the injection characteristics and friction characteristics of the injectors 11 are different in each cylinder due to machine differences and changes over time for each cylinder, and it is also considered that the work amount by each cylinder Sneflt # i varies. It is done. In this respect, by calculating the cylinder-specific work amount Sneflt # i as described above, it is possible to determine how much difference has occurred with respect to the ideal value in each cylinder and how much variation has occurred between the cylinders. I can grasp it. Therefore, when the vehicle travels at a constant speed, the characteristic variation between the cylinders is calculated based on the work amount Sneflt # i for each cylinder, and the fuel injection amount correction based on the work amount Sneflt # i for each cylinder is taken into consideration. It is good to carry out.

  Next, the cruise control process performed by the ECU 20 and the calculation process associated therewith will be described in detail. Here, the calculation process of the cylinder-specific work amount Sneflt # i will be described based on the flowchart of FIG. 4, and the cruise control process will be described based on the flowchart of FIG.

  The calculation processing of the cylinder-specific work amount Sneflt # i shown in FIG. 4 corresponds to the filter means M1, the integration means M2, and the like, and is executed by the ECU 20 when the NE pulse rises.

  In FIG. 4, in step S101, the NE pulse time interval is calculated from the current NE interrupt time and the previous NE interrupt time, and the current rotational speed Ne (instantaneous rotational speed) is calculated by reciprocal calculation of the time interval. ) Is calculated. In the subsequent step S102, the instantaneous torque equivalent value Neflt (i) is calculated using the above equation (1).

In the subsequent step S103, the current NE pulse number is determined. Then, in steps S104 to S107, the work amount Sneflt # i for each cylinder is calculated for each of the first to fourth cylinders using the above equation (3). That is,
If NE pulse number = 0 to 5, calculate the cylinder-specific work amount Sneflt # 1 of the first cylinder (step S104),
If NE pulse number = 6 to 11, the cylinder-specific work amount Sneflt # 3 of the third cylinder is calculated (step S105),
If NE pulse number = 12 to 17, the cylinder specific work amount Sneflt # 4 of the fourth cylinder is calculated (step S106).
If NE pulse number = 18 to 23, the cylinder-specific work amount Sneflt # 2 of the second cylinder is calculated (step S107).

  Further, the cruise control process shown in FIG. 5 is repeatedly executed by the ECU 20 at a predetermined time period. However, FIG. 5 shows only the process of performing the injection amount correction using the cylinder specific work amount Sneflt # i as a parameter in the cruise control process, which will be described below.

  In FIG. 5, first, in step S201, it is determined whether or not the vehicle is currently traveling on a cruise. If the cruise is not being performed, this processing is terminated as it is. If the cruise is being performed, the process proceeds to the subsequent step S202. After that, in step S202, the cylinder specific work amount Sneflt # i calculated in the processing of FIG. 4 is read, and in the subsequent step S203, the fuel correction amount ΔQ is calculated based on the cylinder specific work amount Sneflt # i.

  Here, the fuel correction amount ΔQ is calculated based on the relationship shown in FIG. In FIG. 6, a relationship is given such that the fuel correction amount ΔQ is basically increased as the absolute value of the cylinder-specific work amount Sneflt # i is larger. However, when the cylinder specific work amount Sneflt # i (absolute value) is 0 to A1, the fuel correction amount ΔQ is fixed to zero. Further, an upper limit value MAX is determined as the fuel correction amount ΔQ, and the fuel correction amount ΔQ is guarded by the upper limit value MAX when the cylinder work amount Sneflt # i (absolute value) is A2 or more.

  Thereafter, in step S204, it is determined whether or not the vehicle is in a deceleration tendency. If the vehicle tends to decelerate, the process proceeds to step S205, and the fuel correction amount ΔQ calculated in step S203 is added to the base injection amount Qbase calculated based on various parameters such as engine speed and accelerator opening. The final fuel injection amount Qfin is calculated. If the vehicle tends to accelerate, the process proceeds to step S206, and the final fuel injection amount Qfin is calculated by subtracting the fuel correction amount ΔQ calculated in step S203 from the base injection amount Qbase.

  FIG. 7 is a time chart showing more specifically cruise control in the present embodiment. In FIG. 7, cruise traveling is performed during the entire period shown. In addition, the vehicle travels on a flat road before timing t1 and the vehicle travels on an uphill road after timing t1.

  Before the timing t1 in FIG. 7, the actual vehicle speed has converged near the target vehicle speed, and the cylinder work Sneflt # i calculated based on the instantaneous torque equivalent value Neflt is almost zero. That is, the work amount due to combustion, which is the positive work amount, and the work amount due to the load, which is the negative work amount, are balanced.

  On the other hand, after timing t1, the vehicle speed decreases as the vehicle approaches the uphill road. At this time, since the work amount due to the load increases, the cylinder work amount Sneflt # i increases to the negative side, and the timing t2 at which the cylinder work amount Sneflt # i becomes equal to or greater than a predetermined value A1 (same as A1 in FIG. 6). Thereafter, the fuel injection amount is corrected to the increase side. In the period from timing t3 to t4, the cylinder specific work amount Sneflt # i is equal to or greater than a predetermined value A2 (same as A2 in FIG. 6), and thus the injection amount correction is limited by the upper limit value MAX. By correcting the fuel injection amount to be increased as described above, the vehicle speed returns to the vicinity of the target vehicle speed early after the vehicle speed tends to decrease.

  Incidentally, in normal vehicle speed feedback control, the fuel injection amount increase correction based on the vehicle speed deviation is not performed until the vehicle speed falls to the lower limit set value (the lower limit value of the feedback dead zone). Therefore, when the injection amount correction using the cylinder specific work amount Sneflt # i as a parameter is not performed, the vehicle speed feedback control (correction correction of the fuel injection amount) is started at the timing ta, so the drop in the vehicle speed increases. As a result, the followability of the vehicle speed decreases, but according to the present embodiment, such inconvenience is solved.

  According to the embodiment described above in detail, the following excellent effects can be obtained.

  Since the fuel injection amount is appropriately corrected based on the work amount Sneflt # i for each cylinder of the engine 10 during cruise traveling of the vehicle, it is possible to suppress deterioration in vehicle speed tracking when traveling on a slope or turning the vehicle. Can do. In this case, if it is attempted to recover the vehicle speed by the vehicle speed feedback control, it is considered that an excessive feeling of acceleration or deceleration occurs. However, by performing the fuel injection amount control based on the cylinder-specific work amount Sneflt # i, Sudden deceleration can be suppressed.

  In particular, when a dead zone region (for example, target speed ± 5 km / h) of the vehicle speed feedback control is set, vehicle speed follow-up deteriorates when the vehicle speed decreases or rises on a slope or the like. According to the form, such inconvenience is eliminated.

  As the cylinder specific work amount Sneflt # i (absolute value) increases, the fuel correction amount ΔQ is increased. Therefore, even when the actual vehicle speed largely changes with respect to the target vehicle speed, it is possible to quickly return to the target vehicle speed.

  If the cylinder specific work amount Sneflt # i is less than a predetermined value, the fuel correction amount ΔQ is fixed to 0 (see FIG. 6), so that control hunting can be suppressed. In addition, since the upper limit value MAX is set as the fuel correction amount ΔQ (see FIG. 6), it is possible to suppress deterioration of drivability associated with excessive correction.

  A filter operation is performed at the combustion frequency of the engine 10 for each rotational speed Ne to calculate an instantaneous torque equivalent value Neflt, and the instantaneous torque equivalent value Neflt is integrated for a certain interval for each cylinder, and the work amount for each cylinder Sneflt # Since i is calculated, the work amount Sneflt # i for each cylinder can be preferably calculated.

  Since the band filter (BPF) is used as the filter means, it is possible to remove low-frequency fluctuation components due to acceleration / deceleration and high-frequency fluctuation components such as noise from the rotation speed signal and extract only the torque fluctuation components. Thereby, the calculation accuracy of the cylinder specific work amount Sneflt # i is improved.

  In addition, this invention is not limited to the content of description of the said embodiment, For example, you may implement as follows.

  When the fuel injection amount is corrected based on the work amount for each cylinder during the cruise traveling of the vehicle, a correction limitation is added at the beginning of the correction. For example, when the work amount for each cylinder changes as shown in FIG. 7, the start of the injection amount correction is delayed for a predetermined time (in FIG. 7, it is delayed from the timing t2). Alternatively, the correction amount is corrected to a small value by multiplying by a coefficient (<1). When the correction amount is corrected to a small value, it is preferable to gradually increase the coefficient (slowly approach 1). In this case, sudden acceleration, sudden deceleration, etc. against the driver during cruise traveling can be suppressed, and drivability is improved.

  During turning of the vehicle during cruise traveling, the injection amount correction based on the work amount for each cylinder may be performed on the condition that the steering angle is equal to or greater than a predetermined value. At this time, the injection amount correction may not be performed for a predetermined time from the start of turning of the vehicle, and the injection amount correction may be performed after the predetermined time has elapsed.

In the above embodiment, a section corresponding to one combustion cycle (180 ° CA for a four-cylinder engine)
Integrate the instantaneous torque equivalent value to calculate the work amount for each cylinder (sum of each work amount due to combustion, inertial force, load, etc.). Instead, integrate the instantaneous torque equivalent value in the load torque generation interval. Then, the workload work may be calculated. In this case, during cruise driving, the fuel injection amount is corrected based on the workload.

  In the above embodiment, the band filter (BPF) is used as the filter means for calculating the work by cylinder, but it can be changed to other filter means. For example, LPF or HPF may be used. At this time, by setting the combustion frequency as the response frequency ω of the transfer function that defines LPF or HPF, a desired instantaneous torque equivalent value can be calculated, and the work for each cylinder can be calculated from the instantaneous torque equivalent value.

  Further, the method for calculating the work amount per cylinder of the engine may be changed to another method. For example, it is possible to acquire engine operation information such as engine rotation speed and load as parameters, and to estimate the work for each cylinder using mathematical formulas and maps.

  In the above embodiment, the present invention is embodied in a vehicle equipped with a diesel engine. Alternatively, the present invention may be embodied in a vehicle equipped with a gasoline engine. In this case, the vehicle speed feedback control may be performed by setting the throttle actuator to be controlled during cruise travel (during constant speed travel) and controlling the intake air amount by the operation of the throttle opening by the throttle actuator.

It is a block diagram which shows the outline of the engine control system in embodiment of invention. It is a figure which shows the control block for calculating the work amount according to cylinder. It is a time chart which shows transition of a rotational speed, an instantaneous torque equivalent value, and the work amount according to cylinder. It is a flowchart which shows the calculation process of the work amount according to cylinder. It is a flowchart which shows a cruise control process. It is a figure which shows the relationship between the work amount for each cylinder and the fuel correction amount. It is a time chart which shows the cruise control in this Embodiment more concretely.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Injector, 19 ... Rotation speed sensor, 20 ... ECU, 30 ... Cruise setting apparatus, M1 ... Filter means, M2 ... Integration means.

Claims (8)

In a constant speed traveling control device for a vehicle having constant speed traveling control means for performing vehicle speed feedback control by operating an actuator device mounted on an engine in order to match the vehicle speed with a target value,
Obtaining means for obtaining the work of each cylinder of the engine;
Correction means for correcting an operation amount of the actuator device based on the work amount acquired by the acquisition means during traveling at a constant speed of the vehicle;
A constant-speed traveling control device for a vehicle, comprising: A dead zone region for vehicle speed feedback control is set based on the target value,
2. The constant speed travel control of the vehicle according to claim 1, wherein the constant speed travel control means performs vehicle speed feedback control by operating the actuator device when the vehicle speed changes beyond the dead zone region. 3. apparatus. The correction means increases the correction amount with respect to the operation amount of the actuator device as the difference between the work amount acquired by the acquisition means and a reference value set on the basis of traveling on a flat road of the vehicle is larger. The constant speed traveling control device for a vehicle according to claim 1 or 2, characterized in that The correction means does not correct the operation amount of the actuator device if the difference between the work amount acquired by the acquisition means and a reference value set with reference to when the vehicle is traveling on a flat road is less than a predetermined value. The constant speed travel control device for a vehicle according to any one of claims 1 to 3.   5. The constant speed travel control device for a vehicle according to claim 1, wherein an upper limit value is defined as a correction amount for the operation amount of the actuator device. 6. The correction unit according to claim 1, wherein the correction unit applies a correction limitation at the beginning of the correction when the operation amount of the actuator device is corrected based on the work amount when the vehicle is traveling at a constant speed. A constant speed travel control device for a vehicle according to claim 1. In a control device comprising a rotational speed calculation means for sequentially calculating the rotational speed of the crankshaft of the engine,
The acquisition means includes
Means for filtering the rotational speed calculated by the rotational speed calculating means at a frequency set based on the combustion frequency of the engine to calculate an instantaneous torque equivalent value;
The vehicle constant speed travel control device according to claim 1, further comprising: means for calculating the work amount based on the calculated instantaneous torque equivalent value.   8. The acquisition unit according to claim 7, wherein the acquisition means calculates the work amount or the sum of each of the instantaneous torque equivalent values by integrating each cylinder for a certain interval and combustion, inertial force, and load for each cylinder. A vehicle constant speed travel control device.

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