JP5240062B2 - Coasting control device - Google Patents

Description

  The present invention disengages the clutch interposed between the engine and the drive wheels of the vehicle and disengages the engine when the engine mounted on the vehicle does not perform work that contributes to the traveling of the vehicle. The present invention relates to a coasting control device that performs coasting control for coasting a vehicle.

  In the vehicle, when the accelerator pedal is depressed when the clutch is disengaged, the accelerator is opened and the engine is so-called empty, and the engine speed settles at the engine speed corresponding to the accelerator opening. At this time, the driving force generated by the engine and the engine internal resistance (friction) are balanced, and the engine output torque is zero. That is, the engine does not work at all with respect to the outside, and fuel is wasted.

  The state in which the engine does not work to the outside is not limited to the idling when the clutch is disengaged, but also occurs while the vehicle is running. At this time, the engine simply rotates at an engine speed corresponding to the accelerator opening degree as in the case of flying, and does not contribute to acceleration / deceleration of the vehicle. Therefore, fuel is consumed only for rotating the engine, which is very wasteful.

  The present applicant has proposed a coasting control device that performs coasting control that reduces fuel consumption by disengaging the clutch and returning the engine to an idle state when the engine is rotating but does not work to the outside ( Patent Document 2).

  In coasting control, in a vehicle equipped with a mechanism that can automatically connect and disconnect the clutch, when the engine is rotating but does not work to the outside, the clutch is automatically disconnected and the engine speed is set to the idling speed or equivalent. This is a technique to improve fuel efficiency by setting the number of revolutions.

  The coasting control can be applied to any vehicle that can automatically turn off the engine output (automatically engage / disengage the clutch) as described above. Therefore, the coasting control is not limited to a manual clutch system (manual T / M), but is also automatic. The same effect can be obtained also in other clutch systems (ordinary torque converter AT and AMT).

JP-A-8-67175 JP 2006-342832 A

  However, in Patent Document 2, the clutch may be disengaged even when the driver depresses the accelerator with the intention of accelerating, and the driver feels torque loss when shifting from deceleration to acceleration, and feels uncomfortable. is there.

  Therefore, the present applicant creates a coasting control determination map using the accelerator opening and the clutch rotational speed as indices, and on this coasting control determination map, the coasting where the coordinate points of the accelerator opening and the clutch rotational speed are set in advance. A coasting control device is being developed that starts coasting control when the control threshold line passes in the direction in which the accelerator opening decreases.

  By the way, in the coasting control described above, the engine output torque zero line (no-load line) that serves as a boundary between the negative region where the engine output torque is negative and the positive region where the engine output torque is positive, using the accelerator opening and the clutch rotational speed as indices. ) Is set, and the coasting control threshold line is set based on the no-load line. However, the engine internal resistance (friction) changes depending on the engine temperature, and the engine no-load characteristic changes as the engine internal resistance changes.

  FIG. 10 shows changes in the no-load line (engine no-load characteristics) depending on the lubricating oil temperature. Although it differs depending on the engine, it is generally said that the proper operation is performed when the lubricating oil temperature is around 95 to 100 ° C. (hereinafter referred to as the appropriate oil temperature). With respect to the appropriate oil temperature, the lubricating oil temperature reaches 110 ° C. (hereinafter referred to as “higher oil temperature”) when the outside air is hot or during high load operation, or when the outside oil temperature is low or during low load operation. May fall below 75 ° C. (hereinafter lower oil temperature). Note that these higher and lower oil temperatures are not abnormal oil temperatures, but are general temperatures that are suitable for mass production vehicles.

  As shown in FIG. 10, when the no-load characteristic of the engine changes due to the change in the lubricating oil temperature, the condition for establishing the coasting control changes, and the coasting control may not be performed properly.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a coasting control device capable of appropriately performing coasting control without being affected by changes in engine temperature.

  The present invention has been made to achieve the above object, and when an engine mounted on a vehicle does not perform work that contributes to the traveling of the vehicle, it is interposed between the engine and the drive wheels of the vehicle. A coasting control device that performs coasting control for disengaging the clutch and setting the engine in an idle state to coast the vehicle, using an accelerator opening and a clutch rotational speed as an index, and a predetermined standard temperature range A coasting control determination map in which a no-load line in which the driving force generated by the engine and the engine internal resistance balance is stored in advance, detection means for detecting the lubricating oil temperature or cooling water temperature in the engine, and detection by the detection means When the lubricating oil temperature or the coolant temperature is higher than the standard temperature range, the no-load line is shifted to the low accelerator opening side on the coasting control determination map, When the lubricating oil temperature or cooling water temperature detected by the detecting means is lower than the standard temperature range, in which a correction means for shifting the no-load line to a high accelerator opening side on the coasting control determination map.

  When the lubricating oil temperature or cooling water temperature detected by the detecting means is higher than the standard temperature range, the correcting means shifts the no-load line to the low accelerator opening degree side on the coasting control determination map and the high clutch rotational speed side. When the lubricating oil temperature or cooling water temperature detected by the detection means is lower than the standard temperature range, the no-load line is shifted to the high accelerator opening side and the low clutch rotation speed side on the control determination map. It may be.

  According to the present invention, there is an excellent effect that coasting control can be appropriately performed without being affected by changes in engine temperature.

FIG. 1 is an input / output configuration diagram of a vehicle to which a coasting control device according to an embodiment of the present invention is applied. FIG. 2 is a diagram of a coasting control determination map showing a state in which the no-load line is shifted. FIG. 3 is a block configuration diagram of the lubrication system for explaining the installation position of the oil temperature sensor. FIG. 4 is a block diagram of a vehicle clutch system to which the coasting control device according to the embodiment of the present invention is applied. FIG. 5 is a configuration diagram of an actuator that realizes the clutch system of FIG. 4. FIG. 6 is an operation concept diagram for explaining an outline of coasting control. FIG. 7 is a graph image diagram of the coasting control determination map. FIG. 8 is a graph for explaining the fuel consumption reduction effect by coasting control. FIG. 9 is a diagram of a coasting control determination map in which coasting control is actually performed. FIG. 10 is a graph showing changes in the no-load line (engine no-load characteristics) depending on the lubricating oil temperature.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  As shown in FIG. 1, the vehicle is provided with an electronic control unit (ECU) 11 that mainly controls a transmission and a clutch, and an ECM (engine control module) 12 that mainly controls an engine.

  The electronic control unit 11 includes a shift knob switch, a transmission shift sensor, a select sensor, a neutral switch, a T / M rotation sensor, a vehicle speed sensor, an idle switch, a manual changeover switch, a parking brake switch, a door switch, a brake switch, and a half clutch. The input signal lines of the adjustment switch, clutch sensor, and hydraulic switch are connected. The electronic control unit 11 is connected to the motor and solenoid valve 62 of the hydraulic pump 64 of the clutch system 51, the slope start assisting valve, and the output signal lines of the warning & meter.

  Although not shown, various input signal lines and output signal lines used for engine control are connected to the ECM 12. The ECM 12 can transmit clutch rotation speed, engine rotation speed, accelerator opening degree, and engine rotation change request signals to the electronic control unit 11 via a CAN (Controller Area Network) transmission path.

  When the engine does not perform work that contributes to the running of the vehicle, the clutch is disengaged, and the engine speed is reduced to the idle speed (or the corresponding speed) so that the engine is in an idle state. A coasting control device that performs coasting control for coasting is installed.

  Next, a vehicle equipped with the coasting control device will be described in detail.

  First, a vehicle clutch system will be described.

  As shown in FIG. 4, the vehicle clutch system 51 is a system that combines a manual system and an automatic system controlled by the electronic control unit 11. A clutch master cylinder 53 mechanically coupled to the clutch pedal 52 supplies operating oil to the clutch-free operating cylinder 54. On the other hand, the clutch free actuator unit 55 controlled by the electronic control unit 11 also supplies operating oil to the clutch free operating cylinder 54. The clutch free operating cylinder 54 supplies operating oil to the clutch slave cylinder 56. The piston 57 of the clutch slave cylinder 56 is mechanically connected to the movable part of the clutch 58.

  As shown in FIG. 5, the clutch-free actuator 65 includes an intermediate cylinder 61 that is the clutch-free operating cylinder 54 of FIG. 4, a solenoid valve 62 that constitutes the clutch-free actuator unit 55, a relief valve 63, and a hydraulic pump 64. In the intermediate cylinder 61, a primary piston 66 and a secondary piston 67 are arranged in series. When the primary piston 66 is stroked by the operating oil from the clutch master cylinder 53, the secondary piston 67 is caused to stroke. . Further, the secondary piston 67 is stroked by the operating oil from the clutch-free actuator unit 55. Operating oil is supplied to the clutch slave cylinder 56 in accordance with the stroke of the secondary piston 67. With this configuration, when manual operation is performed, clutch disengagement / engagement is preferentially performed according to manual operation, and when manual operation is not performed, clutch disengagement / engagement is performed as controlled by the electronic control unit 11. The

  Here, the manual and automatic compatible clutch systems have been described, but an automatic clutch system (AT or AMT) may be used.

  Next, the coasting control device will be described.

  First, the operation concept of coasting control will be described with reference to FIG. The horizontal axis shows time and control flow, and the vertical axis shows engine speed. While the accelerator pedal 71 is largely depressed and the accelerator opening degree is 70%, the engine speed 72 increases and the vehicle is accelerated. Assume that the coasting control start condition described later is satisfied when the engine speed 72 is stabilized, the depression of the accelerator pedal 71 is reduced, and the accelerator opening is 35%. By starting coasting control, the clutch is controlled to be disengaged, and the engine speed 72 is controlled to the idle speed. Thereafter, it is assumed that the accelerator pedal 71 is not depressed and the accelerator opening becomes 0% or other coasting control termination conditions are satisfied. When the coasting control ends, the engine is controlled to rotate and the clutch is controlled to contact. In this example, since the accelerator opening is 0%, the engine is braked and the vehicle is decelerated.

  If coasting control is not performed, the engine speed remains high as indicated by the broken line during the coasting control execution period, so that fuel is wasted, but coasting control is performed. Thus, the engine speed 72 becomes the idle speed and fuel is saved.

  Specifically, the coasting control device according to the present embodiment digitally samples the output signal of the accelerator opening sensor every predetermined time, and sets the moving average value as the accelerator opening for every predetermined time. And the accelerator opening speed is calculated by differentiating the accelerator opening for a predetermined time, and when the accelerator opening is negative and its absolute value is smaller than the preset start reference value, coasting control A determination condition detection unit that permits start determination, and an engine output torque zero that serves as a boundary between a negative region where the engine output torque is negative and a positive region where the engine output torque is positive, using the accelerator opening and the clutch rotational speed as an index Coasting control judgment map with coasting control threshold line set along the line (no-load line) and coasting control start judgment are permitted, and coasting control judgment map On-flop, when the coordinate point of the accelerator opening and the clutch rotational speed has passed in the direction of decreasing the accelerator opening the coasting control threshold line, and a coasting control execution determination unit to initiate coasting control.

  Here, the above-described no-load line is in a predetermined standard temperature range (for example, 95 to 100 ° C. as the lubricating oil temperature in the engine). The clutch rotational speed is the rotational speed on the driven side of the clutch and is the same as the rotational speed of the input shaft of the transmission. In the present embodiment, a clutch rotational speed sensor is provided on the input shaft, and the clutch rotational speed is detected from the rotational speed of the input shaft.

  These accelerator opening detection unit, determination condition detection unit, coasting control determination map, and coasting control execution determination unit are preferably mounted on the electronic control unit 11.

  FIG. 7 shows a coasting control determination map as a graph image.

  The coasting control determination map 81 is created by measuring the correlation between the accelerator opening and the clutch rotational speed in advance in the clutch disengaged state for the engine.

  As shown in FIG. 7, the coasting control determination map 81 is a map in which the horizontal axis is the accelerator opening and the vertical axis is the clutch rotational speed. The coasting control determination map 81 can be divided into a minus region M where the engine output torque is negative and a plus region P where the engine output torque is positive. That is, the minus region M is a region where the engine friction is larger than the engine required torque and the engine output torque is negative. The positive region P is a region where the engine output torque is positive because the engine required torque is larger than the engine friction. An engine output torque zero line (no-load line) Z that is a boundary between the minus region M and the plus region P indicates that the engine does not work to the outside and fuel is wasted.

  In this embodiment, the coasting control threshold line T is set slightly to the left of the engine output torque zero line Z of the coasting control determination map 81 (on the side where the accelerator opening is small).

  In the coasting control determination map 81, a coasting controllable area CA having a finite width including the coasting control threshold line T is set between the minus area M and the plus area P.

  In the coasting control determination map 81, a lower limit threshold line U of the clutch rotational speed is set. The lower limit threshold line U defines the lower limit threshold value of the clutch rotational speed regardless of the accelerator opening. The lower limit threshold line U is set slightly higher than the clutch rotational speed in the idle state as shown in the figure.

In the coasting control apparatus according to the present embodiment, coasting control is started when all of the following four coasting start conditions are satisfied.
(1) The accelerator pedal operating speed is within the threshold range (when the accelerator pedal operating speed is below the threshold speed).
(2) Passes the coasting control threshold line T in the accelerator return direction in the coasting control determination map 81 (3) The plot point to the coasting control determination map 81 is in the coasting controllable area CA (4) Engine in the coasting control determination map 81 Rotation speed is lower than threshold line U

In the coasting control device according to the present embodiment, coasting control is terminated when at least one of the following two coasting termination conditions is satisfied.
(1) The accelerator pedal operating speed is outside the threshold range (when the accelerator pedal operating speed exceeds the threshold speed)
(2) The plot point on the coasting control determination map 81 is outside the coasting controllable area CA

  The fuel consumption reduction effect by coasting control will be described with reference to FIG.

  First, it is assumed that coasting control is not performed. The engine speed changes in the range of 1600 to 1700 rpm from about 30 s to about 200 s, and decreases from about 1700 rpm to about 700 rpm (idle speed) between about 200 s and about 260 s. .

  The engine torque increases from about 30 s to about 100 s, but then starts to decrease and continues to decrease to about 150 s. The engine torque is approximately 0 Nm at three locations from about 150 s to about 160 s (ellipse B1), from about 200 s to about 210 s (ellipse B2), and from about 220 s to about 260 s (ellipse B3).

  The fuel consumption (no vertical axis scale; for convenience, it is arranged so as to overlap with the engine torque) changes from about 50 s to about 200 s almost accompanying the transition of the engine torque. Even if the engine torque is approximately 0 Nm, the fuel consumption is not zero.

  If coasting control is performed here, the engine speed is controlled to the idle speed during a period in which the engine torque is approximately 0 Nm. The graph shows a line (thick solid line) of the engine speed during coasting control so as to be separated from a line (solid line) of the clutch rotational speed not performing coasting control. The coasting control was executed three times for ellipses B1, B2 and B3. The fuel consumption amount in the period when the coasting control is performed is lower than the fuel consumption amount when the coasting control is not performed, and it is understood that the fuel consumption is saved.

  FIG. 9 shows a coasting control determination map 100 in which coasting control is actually performed. Each point shows a plot point of the actually detected accelerator opening and clutch rotational speed. In the coasting control determination map 100, a negative region, a positive region, a coasting control threshold line (acceleration 0 threshold point, deceleration 0 threshold point), and a coasting controllable region are set.

  Here, the coasting control device according to the present embodiment includes a detection unit that detects the lubricating oil temperature or the cooling water temperature in the engine, and a no-load line when the lubricating oil temperature or the cooling water temperature detected by the detection unit is higher than the standard temperature range. On the coasting control determination map 81, Z is shifted to the low accelerator opening side (the side where the accelerator opening is small) and to the high clutch rotational speed side, and the lubricating oil temperature or cooling water temperature detected by the detecting means is lower than the standard temperature range. And a correction means for shifting the no-load line Z on the coasting control determination map 81 to the high accelerator opening degree side (the side where the accelerator opening degree is large) and to the low clutch rotation speed side.

  In the present embodiment, the electronic control unit 11 serves as the correction means described above. The detection means includes a water temperature sensor 13 for detecting the cooling water temperature in the engine and an oil temperature sensor 14 for detecting the lubricating oil temperature in the engine.

  The installation position of the water temperature sensor 13 will be described. In the present embodiment, in the engine cooling system, the cooling water that has passed through the radiator is supplied to each part of the engine by a water pump. In the present embodiment, the water temperature sensor 13 is disposed in a cooling water passage near the cooling water outlet (water outlet) of the engine.

  The installation position of the oil temperature sensor 14 will be described. As shown in FIG. 3, in an engine lubrication system, lubricating oil stored in an oil pan is supplied to each part of the engine by an oil pump. In the illustrated example, the oil temperature sensor 14 is disposed in a lubricating oil passage between the oil pump and an oil gallery provided in the engine.

  Further, for example, the no-load characteristics (no-load line) of the engine at a low temperature (for example, 75 ° C.), a standard temperature range (95 to 100 ° C.), and a high temperature (110 ° C.) are obtained through experiments and simulations, respectively. The deviation (acceleration value, accelerator opening) of the no-load line can be set to an amount (correction value) for shifting the no-load line Z.

  Next, the control content of this embodiment is demonstrated.

  First, the electronic control unit 11 acquires the measurement data of the lubricating oil temperature or the cooling water temperature in the engine from the ECM 12, or the measurement data of the lubricating oil temperature or the cooling water temperature in the engine from the oil temperature sensor 14 or the water temperature sensor 13. get.

  Next, the electronic control unit 11 selects a no-load line (Z, ZH, ZL) that matches the acquired lubricating oil temperature or cooling water temperature (see FIG. 2). Specifically, the electronic control unit 11 selects the no-load line Z (no correction) in the standard temperature range if the acquired lubricating oil temperature or cooling water temperature is within the standard temperature range, and the acquired lubricating oil temperature or cooling water temperature is the standard. If it is higher than the temperature range, select the no load line ZH in which the no load line Z in the standard temperature range is shifted to the low accelerator opening side and the high clutch rotational speed side, and if the acquired lubricating oil temperature or cooling water temperature is lower than the standard temperature range The no-load line ZL in which the no-load line Z in the standard temperature range is shifted to the high accelerator opening side and the low clutch rotational speed side is selected.

  Next, the electronic control unit 11 moves the coasting controllable area CA having a finite width including the coasting control threshold line T according to the no-load lines (ZH, ZL) selected above. Specifically, if the acquired lubricating oil temperature or cooling water temperature is higher than the standard temperature range, the electronic control unit 11 sets the coasting controllable area CA according to the selected no-load line ZH to the low accelerator opening side and the high clutch rotation speed side. If the acquired lubricating oil temperature or cooling water temperature is lower than the standard temperature range, the coasting controllable area CA is moved to the high accelerator opening side and the low clutch rotational speed side according to the selected no-load line ZL.

  And the electronic control unit 11 performs coasting control based on the coasting control threshold line T of the coasting control determination map 81, coasting control possible area | region CA, etc. similarly to the above.

  In the present embodiment, as shown in FIG. 2, when the acquired lubricating oil temperature or cooling water temperature is higher than the standard temperature range, the no-load line Z is shifted to the low accelerator opening degree side on the coasting control determination map 81 and the high temperature is increased. Shift to the clutch speed side, and when the acquired lubricating oil temperature or cooling water temperature is lower than the standard temperature range, shift the no-load line Z to the high accelerator opening side and the low clutch speed side on the coasting control determination map 81 However, when the acquired lubricating oil temperature or cooling water temperature is higher than the standard temperature range, the no-load line Z is shifted only on the coasting control determination map 81 to the low accelerator opening side, and the acquired lubricating oil temperature or cooling water temperature is When the temperature is lower than the standard temperature range, the no-load line Z may be shifted only on the coasting control determination map 81 toward the high accelerator opening degree.

  Next, the operation of this embodiment will be described.

  The coasting control device according to the present embodiment confirms the lubricating oil temperature or the cooling water temperature in the engine, and the lubricating oil temperature or the cooling water temperature in the engine is within a reference temperature range (for example, 95 to 100 ° C. at the lubricating oil temperature in the engine). ) Is higher, the no-load line Z stored in advance is shifted on the coasting control determination map 81 to at least the low accelerator opening side, and the lubricating oil temperature or cooling water temperature in the engine is lower than the reference temperature range, the no-load line The stability of coasting control is enhanced by shifting Z on the coasting control determination map 81 at least toward the high accelerator opening.

  As described above, the engine internal resistance (friction) changes depending on the engine temperature, and the engine internal resistance changes, whereby the engine no-load characteristic (no-load line) changes. Specifically, as shown in FIG. 10, when the lubricating oil temperature is higher than the appropriate oil temperature (95 to 100 ° C.), the no-load line is compared with the appropriate oil temperature. If the lubricating oil temperature is lower than the appropriate oil temperature (75 ° C), the no-load line is In comparison, it can be seen that there is a tendency to shift toward the high accelerator opening and the low clutch rotational speed.

  Therefore, in this embodiment, the lubricating oil temperature or the cooling water temperature in the engine is confirmed, and the lubricating oil temperature or the cooling water temperature in the engine is higher than a reference temperature range (for example, 95 to 100 ° C. at the lubricating oil temperature in the engine). In this case, the no-load line Z stored in advance is shifted on the coasting control determination map 81 to at least the low accelerator opening side, and when the lubricating oil temperature or the cooling water temperature in the engine is lower than the reference temperature range, the no-load line Z is coasted. On the control determination map 81, it is shifted to at least the high accelerator opening side.

  By doing so, the no-load line Z stored in advance can be shifted to a place suitable for the lubricating oil temperature or the cooling water temperature, and consequently the coasting control threshold line T and coasting set based on the no-load line Z Since the controllable area CA can be shifted to a position suitable for the lubricating oil temperature or cooling water temperature, even if the engine no-load characteristic changes due to a change in the engine temperature, the change in the no-load characteristic can be followed. Thus, coasting control can be appropriately performed without being affected by changes in engine temperature.

  As shown in FIG. 2, the no-load lines (Z, ZH, ZL) can be divided into about three stages from low temperature to high temperature. Based on the lubricating oil temperature or the cooling water temperature, the no-load line Z in the standard temperature range may be shifted linearly or proportionally. By doing so, it is possible to correct the no-load line Z and the coasting controllable area CA more accurately, and coasting control can be performed more appropriately.

  The engine to which the coasting control device according to the above-described embodiment is applied may be a diesel engine or a gasoline engine.

11 Electronic control unit (correction means)
13 Water temperature sensor (detection means)
14 Oil temperature sensor (detection means)
51 Clutch (Clutch system)
81 coasting control judgment map

Claims (2)

When the engine mounted on the vehicle does not perform work that contributes to the traveling of the vehicle, the clutch interposed between the engine and the drive wheel of the vehicle is disengaged, and the engine is set in an idle state. A coasting control device that performs coasting control for coasting the vehicle,
A coasting control determination map in which a no-load line in which the driving force generated by the engine and the engine internal resistance are balanced in a predetermined standard temperature range is stored in advance using the accelerator opening and the clutch rotational speed as indices.
Detecting means for detecting a lubricating oil temperature or a cooling water temperature in the engine;
When the lubricating oil temperature or cooling water temperature detected by the detecting means is higher than the standard temperature range, the no-load line is shifted to the low accelerator opening side on the coasting control determination map, and the lubricating oil temperature detected by the detecting means or A coasting control apparatus comprising: a correction unit that shifts the no-load line to the high accelerator opening degree side on the coasting control determination map when the cooling water temperature is lower than the standard temperature range.   When the lubricating oil temperature or cooling water temperature detected by the detecting means is higher than the standard temperature range, the correcting means shifts the no-load line to the low accelerator opening degree side on the coasting control determination map and the high clutch rotational speed side. When the lubricating oil temperature or cooling water temperature detected by the detecting means is lower than the standard temperature range, the no-load line is shifted to the high accelerator opening side and to the low clutch rotational speed side on the control determination map. Item 1. The coasting control device according to item 1.

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