JP2011080454A - Device and method for controlling overheat of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure soundness of an engine by earlier determining a foretaste of overheat. <P>SOLUTION: This overheat control device 59 for an engine has: a temperature sensor 54 provided in an engine; and a control unit 42 for regulating a rise of engine speed when the control unit 42 determines a foretaste of overheat of the engine, based on the engine temperature detected by the temperature sensor. The control unit 42 has: a parameter computing section 56 for computing a present value of each of a temperature inclination (m) as the changed quantity of the engine temperature per unit time and a temperature inclination change ratio (n) as the changed quantity per unit time of the temperature inclination; and a determining section 58 for determining a foretaste of overheat based on the present value of the temperature inclination change ratio (n) computed by the parameter computing section. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine overheat control apparatus and method, and more particularly to an engine overheat control apparatus and method installed in an engine mounted on an outboard motor.

  In general, an engine mounted on an outboard motor is a water-cooled engine, and seawater or lake water is sucked as cooling water, and this cooling water is discharged to the outside after cooling each part of the engine. A thermostat is arranged in the cooling water passage through which the cooling water flows, and when the cooling water temperature reaches the thermostat set temperature, the thermostat opens to control the flow of the cooling water, thereby preventing the engine from overheating. .

  Patent Document 1 discloses an overheat control device that detects and controls engine overheating when cooling water shortage occurs due to abnormal cooling water suction or the like. In the overheat detection device described in Patent Document 1, the wall temperature of the engine is determined, the temperature gradient (temperature increase rate) is calculated, and when the temperature gradient exceeds a predetermined value, a sign of overheating is determined. In addition to issuing an alarm, the engine speed is prevented from increasing and overheating is prevented.

Japanese Patent Laid-Open No. 4-60150

  By the way, in recent years, due to a demand for weight reduction of the engine, a margin for thermal deformation of the engine is low. Under such circumstances, the overheat detection device described in Patent Document 1 does not necessarily have an early determination timing for determining a sign of overheating. In the unlikely event, there is a risk of problems such as thermal deformation in the engine. There is.

  An object of the present invention is to provide an engine overheat control device and method capable of ensuring the soundness of an engine by determining an early sign of overheating early in view of the above-described circumstances.

  The engine overheat control device according to the present invention comprises: a temperature sensor installed in the engine; and the engine rotational speed when determining a sign of overheating of the engine based on the temperature of the engine detected by the temperature sensor. An overheat control device for an engine, wherein the control unit uses a change amount per unit time of the temperature of the engine as a temperature gradient, and a change per unit time of the temperature gradient A parameter calculator that calculates the amount of each as a temperature gradient change rate; and a determination unit that determines a sign of the overheating based on the temperature gradient change rate calculated by the parameter calculator. is there.

  In the engine overheat control method according to the present invention, when the temperature of the engine is detected by a temperature sensor installed in the engine, and a sign of the overheating of the engine is determined based on the detected temperature of the engine, An engine overheat control device that regulates an increase in engine speed, wherein a change amount of the engine temperature per unit time is defined as a temperature gradient, and a change amount of the temperature gradient per unit time is defined as a temperature gradient change rate. As the temperature gradient threshold value, a temperature gradient value at which the rate of change in temperature gradient becomes zero is obtained in advance for each engine temperature as the temperature gradient threshold value. If the temperature gradient change rate at that time exceeds a predetermined value of zero or less, the engine auto It is characterized in determining the sign of Hito.

  According to the engine overheat control apparatus and method of the present invention, the temperature gradient is calculated from the engine temperature, the temperature gradient change rate is calculated from the temperature gradient, and the temperature gradient change rate is used to predict the engine overheating. Therefore, it is possible to determine the sign of the engine overheating earlier than the case where the sign of the engine overheating is determined using the temperature gradient. For this reason, generation | occurrence | production of overheating can be prevented reliably and the soundness of an engine can be ensured.

1 is a right side view showing an outboard motor to which an embodiment of an engine overheat control device according to the present invention is applied. The perspective view which shows the cylinder block etc. of the engine of FIG. The graph which shows the relationship between the wall temperature of a cylinder block, and time. The graph which shows the relationship between the wall temperature of a cylinder block, and its temperature gradient. The graph which shows the relationship between the wall temperature of a cylinder block, and a temperature gradient change rate. The chart which shows the temperature gradient threshold value for every wall temperature of a cylinder block. The flowchart which shows the operation | movement which the parameter calculating part and determination part of FIG. 2 perform.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the present invention is not limited to these embodiments.

  FIG. 1 is a right side view showing an outboard motor to which an embodiment of an engine overheat control apparatus according to the present invention is applied.

  As shown in FIG. 1, the outboard motor 10 drives the propeller 15 by the driving force of the mounted engine 14 to generate a propulsive force forward or outboard of the outboard motor. A mounting bracket device 12 as mounting means for supporting the outboard motor main body 11 and mounting it to the transom 16A of the hull 16, and an upper mount unit disposed between the outboard motor main body 11 and the mounting bracket device 12. 17 and a lower mount unit 18.

  The outboard motor main body 11 includes an engine holder 20, and the engine 14 is mounted on the engine holder 20. An oil pan 21 is disposed below the engine holder 20, a drive shaft housing 22 is installed below the oil pan 21, and a gear case 23 is installed below the drive shaft housing 22. The engine 14, the engine holder 20, and the oil pan 21 are covered with an engine cover 24.

  The engine 14 includes a crankcase 25, a cylinder block 26, a cylinder head 27, and a head cover 32 that are sequentially arranged from the front of the outboard motor to the rear of the outboard motor. Cylinders 19 </ b> A, 19 </ b> B, and 19 </ b> C (FIG. 2) in which pistons (not shown) reciprocate are formed in the cylinder block 26 in a substantially horizontal direction, and the crankshaft 28 is substantially between the crankcase 25 and the cylinder block 26. It is arranged in the vertical direction. As described above, the engine 14 is configured as a vertical type in which the cylinders 19A, 19B, and 19C are arranged in a substantially horizontal direction and the crankshaft 28 is arranged in a substantially vertical direction.

  A drive shaft 29 is connected to the lower end portion of the crankshaft 28 of the engine 14 in the same straight line, for example, splined. The drive shaft 29 extends substantially vertically in the engine holder 20, the oil pan 21, the drive shaft housing 22, and the gear case 23, and is connected to the propeller shaft 31 via a bevel gear 30 in the gear case 23. Thereby, the driving force of the engine 14 (that is, the rotational force of the crankshaft 28) is transmitted to the propeller 15 coupled to the propeller shaft 31 via the drive shaft 29, the bevel gear 30 and the propeller shaft 31.

  The mounting bracket device 12 includes a clamp bracket 35, a swivel bracket 36, a pilot shaft (steering shaft) 37, an upper mount bracket 38, and a lower mount bracket 39. The clamp bracket 35 is provided so that the transom 16A of the hull 16 can be gripped. The swivel bracket 36 is supported by the clamp bracket 35 via a swivel shaft 40 so as to be rotatable in the vertical direction.

  The pilot shaft 37 extends in the vertical direction on the swivel bracket 36 and is rotatably provided. The upper mount bracket 38 that also serves as the base end portion of the steering bracket 41 is coupled to the upper end of the pilot shaft 37, and the lower mount bracket 39 is coupled to the lower end of the pilot shaft 37 so as to rotate together. The outboard motor main body 11 is attached to the upper mount bracket 38 via the upper mount unit 17 and to the lower mount bracket 39 via the lower mount unit 18.

  As a result, the outboard motor main body 11 is pivotally supported so as to be pivotable in the left-right direction with respect to the clamp bracket 35 and the swivel bracket 36 around the pilot shaft 37, and together with the swivel bracket 36 about the swivel shaft 40. The clamp bracket 35 is pivotally supported so as to be pivotable in the vertical direction (tilt operation and trim operation).

  The engine 14 is a water-cooled four-cycle three-cylinder engine in which a plurality of (for example, three) cylinders 19A, 19B, 19C (FIG. 2) extending in the horizontal direction are arranged in a vertical direction on a cylinder block 26. . Around the engine 14, an electrical component including a control unit (ECU) 42 and an exhaust device 43 are arranged on the right side, and an intake device (not shown) is arranged on the left side.

  As shown in FIG. 2, the exhaust device 43 is configured such that an exhaust manifold 44 as an exhaust collecting portion is provided on a side of the cylinder block 26 in the engine 14 so as to extend in the vertical direction. An exhaust passage 45 communicating with the exhaust passage 45 is provided. The exhaust passage 45 of the exhaust manifold 44 communicates with an exhaust passage (not shown) formed in the engine holder 20 to collect exhaust from the exhaust port of the engine 14 and to the exhaust passage of the engine holder 20. Lead.

  Exhaust gas is guided from an exhaust passage of the engine holder 20 through an exhaust passage (not shown) of the oil pan 21 shown in FIG. 1 to an exhaust expansion chamber (not shown) of the drive shaft housing 22 to be expanded and silenced. Thereafter, the exhaust gas is mainly discharged into the water through an exhaust passage 46 formed around the propeller shaft 31 in the gear case 23.

  The engine 14 is water-cooled, and uses, for example, seawater or lake water as cooling water. That is, as shown in FIG. 1, the cooling water is taken in from the water intake 48 provided in the gear case 23 by the water pump 47 driven by the drive shaft 29. This cooling water is guided to a cooling water introduction passage (not shown) formed in the engine holder 20 through a water tube (not shown), and a water jacket 49 (FIG. 2) around each cylinder 19A, 19B, 19C in the cylinder block 26. ) And a water jacket (not shown) around each combustion chamber in the cylinder head 27 to cool the cylinders 19A to 19C and the combustion chamber.

  Further, as shown in FIG. 2, the cooling water guided to the cooling water introduction passage of the engine holder 20 is supplied to the water jacket 50 and the cylinder head 27 formed around the exhaust passage 45 of the exhaust manifold 44 in the cylinder block 26. Guided to a water jacket (not shown) formed around each exhaust port, the exhaust passage 45 and the exhaust port are cooled. Note that reference numeral 51 in FIG. 2 denotes a water jacket lid for forming the water jacket 50.

  Cooling water that has cooled the cylinders 19A to 19C, the combustion chamber, the exhaust passage 45 of the exhaust manifold 44, and the exhaust port passes through a thermostat 52 and a cooling water return hose 53, and reaches a cooling water discharge passage (not shown) of the engine holder 20. From the cooling water discharge passage, it flows down to the exhaust expansion chamber of the drive shaft housing 22 shown in FIG. 1 and is discharged into the water from the exhaust passage 46 around the propeller shaft 31 of the gear case 23.

  The thermostat 52 is installed in the middle of the cooling water passage including the water jackets 49 and 50 and the cooling return hose 53 (in this embodiment, the cooling water passage of the cylinder block 26). When the temperature reaches the thermostat set temperature, the opening operation is performed to cause the cooling water to flow in the cooling water passage. By controlling the flow of the cooling water by the thermostat 52 in this way, the cooling water temperature is maintained below the thermostat set temperature, and overheating of the engine 14 is prevented.

  The cylinder block 26 is provided with a temperature sensor 54 that detects the wall temperature T of the cylinder block 26 adjacent to the thermostat 52. The temperature detected by the temperature sensor 54 is transmitted to the control unit 42. The control unit 42 drives the alarm generator 55 to generate an alarm when determining a sign of overheating of the engine 14 based on the wall temperature T of the cylinder block 26 detected by the temperature sensor 54, and generates an alarm. The ignition coil is controlled to restrict an increase in engine speed, and an increase in temperature of the engine 14 is suppressed.

  The control unit 42 includes a parameter calculation unit 56, a database unit 57, and a determination unit 58 in order to determine a sign of overheating of the engine 14. The overheat control device 59 is configured by including the control unit 42 including the parameter calculation unit 56, the database unit 57, and the determination unit 58 and the temperature sensor 54.

The parameter calculation unit 56 calculates the current value of the wall temperature T detected by the temperature sensor 54 from the current value of the wall temperature T of the cylinder block 26 with the amount of change ΔT per unit time (Δt) as the temperature gradient m. To do. Furthermore, the parameter calculation unit 56 calculates the current value of the temperature gradient change rate n as the change rate Δm per unit time (Δt) of the temperature gradient m.
[Equation 1]
m = ΔT / Δt, n = Δm / Δt

  Curves A0, B0, and C0 shown in FIG. 3 indicate the wall temperature T in the cylinder block 26 when the engine 14 is rotated at a high speed in normal times A, B, and C, respectively, where there is no shortage of cooling water in the cooling water passage. Shows time change. The normal times A, B, and C are cases where the temperatures at the start of the engine 14 are Ta, Tb, and Tc (Ta <Tb <Tc), respectively. The wall temperature T of the cylinder block 26 finally reaches the vicinity of the same temperature (thermostat set temperature Td) controlled by the thermostat 52 (FIG. 2) even if the wall temperature T at the start of the engine 14 is different. .

  Also, the curves A1, B1, and C1 shown in FIG. 4 indicate the temperature gradient m in relation to the wall temperature T with respect to the wall temperature T of the cylinder block 26 indicated by the curves A0, B0, and C0 in FIG. Is. Even if the wall temperature T of the cylinder block 26 is different at the time of starting the engine 14, the wall temperature T finally reaches substantially the same thermostat set temperature Td, so that the peak values m 1 and m 2 in the temperature gradient m of the wall temperature T of the cylinder block 26 are reached. , M3 becomes lower as the wall temperature T of the cylinder block 26 at the start of the engine 14 is higher, as shown in FIG.

  Furthermore, the curves A2, B2, and C2 shown in FIG. 5 indicate the temperature gradient change rate n of the wall temperature T with respect to the temperature gradient m of the wall temperature T of the cylinder block 26 indicated by the curves A1, B1, and C1 in FIG. It is shown in relation to In normal times A, B, and C in which there is no cooling water shortage in the cooling water passage, the temperature gradient change rate n is 0 (n = 0) at the peak of the temperature gradient m, and the temperature gradient m has peak values m1, m2, In the temperature range after exceeding m3, the temperature gradient change rate n is less than or equal to zero (n <0).

  Here, the peak value of the temperature gradient m at which the rate of change in temperature gradient n is zero is measured by experiment or the like at normal times when there is no cooling water shortage in the cooling water passage. A gradient threshold value M is obtained in advance for each wall temperature T of the cylinder block 26. In the database unit 57 (FIG. 2), as shown in FIG. 6, the obtained temperature gradient threshold value M is stored in advance in association with the wall temperature T of the cylinder block 26 at that time. In this temperature gradient threshold value M, peak values m1, m2, and m3 of the temperature gradient m shown in FIG. 4 are stored in association with the wall temperatures T1, T2, and T3 of the cylinder block 26 at that time.

  A curve P0 shown in FIG. 3 indicates that the engine 14 is rotated at a high speed from the start-up temperature Tb when the cooling water passage is insufficient due to a malfunction of the water pump 47 (FIG. 1) or clogging of the intake port 48. The time change of the wall temperature T of the cylinder block 26 produced when it is made to show is shown.

  A curve P1 shown in FIG. 4 shows the temperature gradient m in relation to the wall temperature T of the wall temperature T of the cylinder block 26 indicated by the curve P0 in FIG. The curve (straight line) O shown in FIG. 4 is formed by plotting each value of the temperature gradient threshold value M in FIG. 6, and the peak value m1 of the curve A1, the peak value m2 of the curve B1, and the curve Each includes a peak value m3 of C1.

  A curve P2 shown in FIG. 5 shows the temperature gradient change rate n in relation to the wall temperature T with respect to the temperature gradient m of the wall temperature T of the cylinder block 26 indicated by the curve P1 in FIG. In the curve P2, the value of the temperature gradient change rate n reaches the wall temperature Tp as shown in FIG. 5 in a temperature range equal to or higher than the wall temperature Tp of the cylinder block 26 where the curve P1 of FIG. As in the case of the temperature range up to, the value exceeds zero (n> 0).

  The determination unit 58 (FIG. 2) determines overheating of the engine 14 based on the temperature gradient change rate n at the wall temperature T of the cylinder block 26 calculated by the parameter calculation unit 56. That is, the determination unit 58 is a temperature region where the temperature gradient m with respect to the current wall temperature T of the cylinder block 26 detected by the temperature sensor 54 exceeds the temperature gradient threshold value M (T ≧ Tp), When the value of the temperature gradient change rate n exceeds the predetermined value (in this embodiment, the predetermined value is zero) (n> 0), it is determined that the engine 14 has a sign of overheating. The predetermined value is not limited to zero, and may be a value equal to or less than zero, such as -0.1, -0.2, and the like.

  Next, an overheat sign determination procedure executed by the overheat control device 59 will be described with reference to FIG.

  The temperature sensor 54 constantly detects the current value of the wall temperature T of the cylinder block 26 during operation of the engine 14 (S11). The parameter calculation unit 56 of the control unit 42 calculates the current values of the temperature gradient m and the temperature gradient change rate n from the current value of the wall temperature T detected by the temperature sensor 54 (S12).

  The determination unit 58 of the control unit 42 reads the temperature gradient threshold value M (mi) corresponding to the current wall temperature T of the cylinder block 26 (S13), and calculates the temperature gradient threshold value M (mi) and parameter calculation. The unit 56 compares the current temperature gradient m calculated from the current wall temperature T with the unit 56 (S14).

  When the temperature gradient m of the current wall temperature T exceeds the temperature gradient threshold value M (mi) at the wall temperature T, the determination unit 58 then changes the temperature gradient at the current wall temperature T. It is determined whether the rate n is greater than or equal to zero (n> 0) (S15). In step S15, when the temperature gradient change rate n at the current wall temperature T is equal to or greater than zero (n> 0), the determination unit 58 determines that the engine 14 has a sign of overheating (S16).

  When the determination unit 58 determines that there is a sign of overheating, the control unit 42 operates the alarm generator 55 to generate an alarm, and at the same time, controls the injector and the ignition coil to control the rotational speed of the engine 14. Is suppressed, and the temperature increase of the engine 14 is suppressed.

  Since it was configured as described above, according to the present embodiment, the following effects (1) and (2) are achieved.

  (1) The temperature sensor 54 constantly detects the wall temperature T of the cylinder block 26 of the engine 14, and the parameter calculation unit 56 of the control unit 42 calculates the temperature gradient m from the detected current value of the wall temperature T of the cylinder block 26. The current value is calculated, and the current value of the temperature gradient change rate n is calculated from the current value of the temperature gradient m. Then, when the temperature gradient m at the current wall temperature T exceeds the temperature gradient threshold value M (mi) at the current wall temperature T stored in the database unit 57, the determination unit 58 determines that the wall temperature When the temperature gradient change rate n at T exceeds zero (n> 0), a sign of overheating of the engine 14 is determined.

  For this reason, the determination timing of the sign of overheating of the engine 14 is the time tβ (FIG. 3) when the current value of the conventional temperature gradient m is used, whereas the temperature gradient change rate n of the present embodiment. The time when the current value is used is the time point tα (FIG. 3), and the sign of overheating of the engine 14 can be determined early. For this reason, generation | occurrence | production of overheating can be prevented reliably and malfunctions, such as a thermal deformation, can generate | occur | produce in the engine 14, Therefore The soundness of the engine 14 is securable.

  (2) Since the determination unit 58 of the control unit 42 determines the sign of overheating at an early stage, even when the temperature sensor 54 is installed in a portion of the cylinder block 26 where the temperature rise is delayed, the sign of overheating is determined. It's never too late. For this reason, the degree of freedom of arrangement (layout) of the temperature sensor 54 is improved, and the outboard motor 10 can be made compact.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this. For example, the temperature gradient threshold value M stored in the database unit 57 as shown in FIG. 6 may be learned by the control unit based on the operation history of the engine 14.

DESCRIPTION OF SYMBOLS 10 Outboard motor 14 Engine 26 Cylinder block 42 Control unit 54 Temperature sensor 56 Parameter calculation part 57 Database part 58 Determination part 59 Overheat control apparatus T Wall temperature m Temperature gradient n Temperature gradient change rate M Temperature gradient threshold value

Claims (4)

A temperature sensor installed in the engine;
A control unit that regulates an increase in the rotational speed of the engine when determining a sign of overheating of the engine based on the temperature of the engine detected by the temperature sensor,
The control unit includes a parameter calculator that calculates a change amount per unit time of the engine temperature as a temperature gradient, and calculates a change amount per unit time of the temperature gradient as a temperature gradient change rate, respectively.
An engine overheat control device comprising: a determination unit that determines a sign of the overheating based on a temperature gradient change rate calculated by the parameter calculation unit. The control unit includes a database unit that stores in advance the temperature gradient value at which the rate of change in temperature gradient becomes zero as a temperature gradient threshold value, in association with the temperature of the engine at that time,
When the temperature gradient with respect to the current engine temperature exceeds the temperature gradient threshold, and the rate of change in temperature gradient exceeds a predetermined value of zero or less, the determination unit of the control unit The engine overheat control device according to claim 1, wherein the engine overheat control device is configured to determine a sign of overheating of the engine. The engine overheat control device according to claim 2, wherein the predetermined value when the determination unit determines a sign of overheating is a value of zero temperature gradient change rate. When the temperature of the engine is detected by a temperature sensor installed in the engine and a sign of overheating of the engine is determined based on the detected temperature of the engine, the engine overheating restricts the increase in the engine speed. A control device,
The amount of change in the engine temperature per unit time is defined as a temperature gradient, and the amount of change in the temperature gradient per unit time is calculated as a temperature gradient change rate.
The value of the temperature gradient at which the temperature gradient change rate becomes zero is obtained in advance for each engine temperature as a temperature gradient threshold,
When the temperature gradient with respect to the current engine temperature exceeds the temperature gradient threshold and the rate of change in temperature gradient exceeds a predetermined value of zero or less, a pre-sign of the engine overheating is determined. An overheat control method for an engine.

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