JP3859036B2 - Overheat prevention device for vehicle engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an overheat prevention device for a vehicle engine, and in particular, can prevent overheating without incurring an increase in cost, can cancel fuel cut control at the driver's will, and overheats in all speed conditions. The present invention relates to an overheat prevention device for a vehicle engine that can prevent overheating regardless of whether it is a manual transmission or an automatic transmission.
[0002]
[Prior art]
A vehicle engine mounted on a vehicle has a problem of overheating when the engine speed is operated at a maximum allowable speed or more (over rev). Therefore, some vehicle engines are provided with a fuel cut device in order to prevent the engine speed from exceeding the maximum allowable speed.
[0003]
In this device, as shown in FIG. 6, the maximum allowable engine speed is set as an overlev prevention fuel cut speed NeC, and when the engine speed Ne exceeds the overrev prevention fuel cut speed NeC (Ne> NeC). The fuel cut is performed to reduce the engine speed.
[0004]
Such overheat prevention devices for vehicle engines are disclosed in Japanese Patent Application Laid-Open No. 63-176646 and Utility Model Registration No. 2544062.
[0005]
Japanese Patent Laid-Open No. 63-176646 discloses an overheat prevention device that cuts fuel when the engine speed exceeds the fuel cut speed and restarts fuel injection when the engine speed falls below the fuel return speed. If the accelerator pedal is depressed and the engine speed is abnormally high and an abnormal condition just before overheating is detected, the fuel cut speed and the fuel return speed are gradually reduced to reduce overheating. It is an effective prevention.
[0006]
Japanese Utility Model Registration No. 2544062 discloses an overheat prevention device that reduces engine output in response to the engine speed exceeding the set speed, and the state where the cooling water temperature exceeds the set temperature continues for a predetermined time. In this case, the engine overheat is predicted and the set rotational speed is reduced according to the vehicle speed in accordance with the overheat prediction.
[0007]
[Problems to be solved by the invention]
Incidentally, as shown in FIG. 6, the vehicle engine has a maximum allowable rotational speed (overlev prevention fuel cut rotational speed) NeC. However, in a normal driving state, the maximum normal rotational speed NeG corresponding to each vehicle speed. Is decided.
[0008]
However, the vehicular engine is in an area exceeding the normal use maximum speed NeG corresponding to each vehicle speed and less than the maximum allowable speed (over-rev preventing fuel cut speed) NeC (hereinafter referred to as “overspeed area”). There may be a rotation speed.
[0009]
For this reason, the vehicle engine has a problem of overheating when it is continuously operated in an overspeed range where the engine speed exceeds the normal use maximum speed NeG and is less than the maximum allowable speed NeC. .
[0010]
[Means for Solving the Problems]
Therefore, in order to eliminate the above-mentioned inconveniences, the present invention is such that when the vehicle engine mounted on the vehicle is in a completely warmed-up state, the engine speed exceeds the overspeed determination speed, and this state increases the overspeed determination time. If the engine speed continues, the fuel cut control is executed so that the engine speed is maintained between the overspeed prevention fuel cut speed and the overspeed prevention fuel cut return speed, and the engine speed is overspeeded. A control means is provided for canceling the fuel cut control and executing a normal control when the engine speed is less than the return judgment speed . The control means includes the overspeed judgment speed and the overspeed prevention fuel cut. and rotational speed, and the the overspeed fuel cut return rotational speed, and the overspeed restoration judgment rotation speed, characterized in that it is set as the vehicle speed of the vehicle becomes higher as the higher, the control hand To, the overspeed determination time, characterized by providing set to be longer as the vehicle speed increases.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In the overheat prevention device of the present invention, when the engine speed exceeds the overspeed determination speed when the vehicle engine is completely warmed up by the control means, and this state continues beyond the overspeed determination time, The fuel cut control is executed so that the engine speed is maintained between the overspeed prevention fuel cut speed and the overspeed prevention fuel cut return speed, and the engine speed is less than the overspeed return determination speed. In this case, the fuel cut control is canceled and normal control is executed. In the control means, the over-rotation determination rotation speed, the over-rotation prevention fuel cut rotation speed, the over-rotation prevention fuel cut return rotation speed, and the over-rotation return determination rotation speed are increased as the vehicle speed of the vehicle increases. Set to.
[0012]
As a result, this overheat prevention device does not require a separate sensor or the like to be added to the vehicle engine, and can prevent overheating by changing a program such as an existing fuel control system in the vehicle engine. By executing the cut, the driver can be made to detect an abnormality before the engine water temperature of the vehicle engine becomes too high from the fully warmed-up temperature. If the driver notices an abnormality, the fuel cut control is canceled. In addition, it can be continuously controlled not only when the vehicle is stopped and at the highest speed, but also at each intermediate vehicle speed, and overheating due to slippage of the clutch of the manual transmission or slipping of the torque converter of the automatic transmission can be prevented. .
[0013]
【Example】
Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show an embodiment of the present invention. In FIG. 4, 2 is a vehicle engine mounted on a vehicle (not shown), 4 is a fuel injection valve as fuel supply means, and 6 is an overheat prevention device.
[0014]
The vehicle engine 2 is provided with a fuel injection valve 4 that supplies fuel connected to a control means 8 that constitutes an overheat prevention device 6. The control means 8 is provided with an engine speed sensor 10, a vehicle speed sensor 12, and a water temperature sensor 14 connected thereto. The control means 8 controls the fuel injection valve 4 to inject and supply an appropriate amount of fuel to the vehicle engine 2.
[0015]
The control means 8 of the overheat prevention device 6 inputs the engine speed Ne, the vehicle speed V, and the engine water temperature TW from the engine speed sensor 10, the vehicle speed sensor 12, and the water temperature sensor 14, respectively, and these values are set in advance. It is determined whether the condition is satisfied or not compared with various conditions, and fuel cut control and normal control are executed according to the determination.
[0016]
As shown in FIG. 3, the control means 8 includes an overspeed determination rotation speed NeUP, an overspeed prevention fuel cut speed NeFC, an overspeed prevention fuel cut return speed NeFR, and an overspeed return determination speed for each vehicle speed V. A number NeDown is set and provided, and a complete warm-up determination water temperature TWo and an over-rotation determination time TNe are set and provided.
[0017]
The overspeed determination speed NeUP is a normal use maximum speed (see FIG. 6) determined corresponding to each vehicle speed V in a normal driving state. The overspeed prevention fuel cut speed NeFC is a speed lower than the overspeed determination speed NeUP and is a speed at which the fuel is cut. The overspeed prevention fuel cut return speed NeFR is lower than the overspeed prevention fuel cut speed NeFC, and is the speed at which the fuel cut returns to the fuel supply.
[0018]
Further, the overspeed return determination speed NeDown is a speed lower than the overspeed prevention fuel cut return speed NeFR, and is a speed at which the fuel cut control is canceled and normal control is executed. The over-rotation determination rotation speed NeUP, the over-rotation prevention fuel cut rotation speed NeFC, the over-rotation prevention fuel cut return rotation speed NeFR, and the over-rotation return determination rotation speed NeDown are determined by the vehicle type and the vehicle engine 2 to be mounted. It is determined in consideration of the displacement and the gear ratio of the transmission.
[0019]
When the vehicle engine 2 is completely warmed up, the control means 8 determines that the engine speed Ne exceeds the over-rotation determination speed NeUP and this state continues beyond the over-rotation determination time TNe. The fuel cut control is executed so that Ne is maintained between the overspeed prevention fuel cut speed NeFC and the overspeed prevention fuel cut return speed NeFR, and the engine speed Ne is less than the overspeed return determination speed NeDown. If this happens, the fuel cut control is canceled and normal control is executed.
[0020]
Next, the operation of this embodiment will be described based on the flowchart of FIG.
[0021]
When the control program starts (step 100), the control means 8 determines whether or not the engine water temperature TW has exceeded the complete warm-up determination water temperature TWo (step 102).
[0022]
In this determination (step 102), when TW ≦ TWo and NO, this determination (step 102) is repeated. In this determination (step 102), if TW> TWo and YES, it is determined whether or not the engine speed Ne has exceeded the overspeed determination speed NeUP set for each vehicle speed V (step 104).
[0023]
In this determination (step 104), if Ne ≦ NeUP and NO, the process returns to the determination (step 102). In this determination (step 104), if the engine speed Ne enters the overspeed region of FIG. 6 and Ne> NeUP and YES, the time T during which Ne> NeUP continues exceeds the overspeed determination time TNe. It is determined whether or not (step 106).
[0024]
In this determination (step 106), if T ≦ TNe and NO, the process returns to the determination (step 102). In this determination (step 106), if T> TNe and YES, an overspeed prevention fuel cut speed NeFC and an overspeed prevention fuel cut return speed NeFR corresponding to the vehicle speed V are set and fuel cut control is performed. Execute (step 108).
[0025]
In this process (step 108), the control means 8 cuts the fuel and lowers the engine speed Ne when the increasing engine speed Ne reaches the overspeed prevention fuel cut speed NeFC set for each vehicle speed V. On the other hand, when the descending engine speed Ne reaches the overspeed prevention fuel cut return speed NeFR set for each vehicle speed V, the fuel is returned from the fuel cut and fuel is supplied.
[0026]
Thereby, the control means 8 performs fuel cut control so that the engine speed Ne is maintained between the overspeed prevention fuel cut speed NeFC and the overspeed prevention fuel cut return speed NeFR.
[0027]
During the process (step 108), it is determined whether or not the engine speed Ne has become less than the overspeed return determination speed NeDown (step 110).
[0028]
In this determination (step 110), if Ne ≧ NeDown and NO, the process returns to the process (step 104). In this determination (step 110), if the driver rotates the accelerator pedal and the engine speed Ne decreases and Ne> NeDown and YES, the overspeed prevention fuel cut speed NeFC and the overspeed prevention fuel are determined. The cut return rotational speed NeFR is canceled (step 112), and the process returns to (step 102).
[0029]
Thereby, the control means 8 cancels fuel cut control, and performs normal control, when the engine speed Ne becomes less than the over-rotation return determination speed NeDown.
[0030]
In this way, as shown in FIG. 3, the overheat prevention device 6 has an overspeed determination rotational speed NeUP, an overspeed prevention fuel cut speed NeFC, an overspeed prevention fuel cut return speed NeFR, and an overspeed at each vehicle speed V of the vehicle. As shown in FIG. 2, when the vehicle engine 2 is completely warmed up, the engine speed Ne exceeds the over-rotation determination speed NeUP and is set by the control means 8 as shown in FIG. When the state continues beyond the overspeed determination time TNe, the fuel cut control is performed so that the engine speed Ne is maintained between the overspeed prevention fuel cut speed NeFC and the overspeed prevention fuel cut return speed NeFR. When the engine speed Ne is less than the over-return return determination speed NeDown, the fuel cut control is canceled and the normal control is performed. Row.
[0031]
As a result, this overheat prevention device 6 does not require a separate sensor or the like to be added to the vehicle engine 2 and realizes prevention of overheating by changing the program using an existing fuel control system or the like in the vehicle engine 2. In addition, it is possible to cause the driver to detect an abnormality before the engine water temperature TW of the vehicle engine 2 becomes too high from the fully warm-up temperature TWo by executing the fuel cut.
[0032]
In addition, the overheat prevention device 6 can cancel the fuel cut control by a driver who notices an abnormality returning the accelerator pedal to lower the engine speed Ne to less than the overspeed return determination speed NeDown. Moreover, it is possible to control continuously not only when the vehicle is stopped and when traveling at the highest speed, but also for each intermediate vehicle speed.
[0033]
Furthermore, the overheat prevention device 6 can prevent overheating when the engine speed Ne exceeds the set overspeed determination speed NeUP due to slippage of the clutch of the manual transmission, and the oil is significantly reduced. Can prevent overheating when the engine speed Ne exceeds the over-rotation determination speed NeUP due to slippage of the torque converter of the automatic transmission, and further, the driver can perform driving operation exceeding the over-rotation determination speed NeUP. It is possible to prevent overheating in the case of.
[0034]
For this reason, this overheat prevention device 6 can realize overheat prevention without incurring an increase in cost, and can cancel the fuel cut control at the driver's will, from the stop of the vehicle to the maximum vehicle speed. Overheating can be prevented in all speed states, and overheating can be prevented regardless of whether the transmission is a manual transmission or an automatic transmission, and overheating due to a driver's erroneous operation or the like can be prevented.
[0035]
In this embodiment, the over-rotation determination time TNe is set to a fixed value. However, as shown in FIG. 5, the over-rotation determination time T Ne is set in the control means 8 for each vehicle speed V. Thus, the over-rotation determination time TNe can be changed for each vehicle speed V, and overheating can be prevented more efficiently.
[0036]
【The invention's effect】
As described above, the overheat prevention apparatus of the present invention does not require a separate sensor or the like to be added to the vehicle engine, and can prevent overheating by changing a program such as an existing fuel control system in the vehicle engine. It is possible to cause the driver to detect an abnormality before the coolant temperature of the vehicle engine becomes too high from the fully warmed-up temperature by performing the fuel cut, and if the driver notices an abnormality, the fuel cut is performed. Control can be released and continuously controlled not only when the vehicle is stopped and at the highest speed, but also at each intermediate vehicle speed, overheating due to slippage of the clutch of the manual transmission, slipping of the torque converter of the automatic transmission, etc. Can prevent.
[0037]
For this reason, this overheat prevention device can realize overheat prevention without incurring an increase in cost, can cancel the fuel cut control at the driver's will, and can operate at any speed from the stop of the vehicle to the maximum vehicle speed. It is possible to prevent overheating in the state, to prevent overheating regardless of the manual transmission / automatic transmission, and it is possible to prevent overheating due to erroneous operation of the driver.
[Brief description of the drawings]
FIG. 1 is a control flowchart showing an embodiment of an overheat prevention apparatus.
FIG. 2 is a timing chart of control of the overheat prevention device.
FIG. 3 is a diagram showing a relationship between each control rotation speed set for each vehicle speed.
FIG. 4 is a block diagram of an overheat prevention device.
FIG. 5 is a diagram illustrating setting of an over-rotation determination time based on vehicle speed.
FIG. 6 is a diagram showing a relationship between a maximum allowable rotation speed depending on a vehicle speed and a normal use maximum rotation speed.
[Explanation of symbols]
2 Vehicle Engine 4 Fuel Injection Valve 6 Overheat Prevention Device 8 Control Means 10 Engine Speed Sensor 12 Vehicle Speed Sensor 14 Water Temperature Sensor

Claims (2)

When the vehicle engine mounted on the vehicle is completely warmed up, if the engine speed exceeds the overspeed determination speed and this state continues beyond the overspeed determination time, the engine speed is prevented from overspeeding. The fuel cut control is executed so as to be maintained between the fuel cut speed and the overspeed prevention fuel cut return speed, and when the engine speed becomes less than the overspeed return determination speed, the fuel cut is performed. Control means for canceling the control and performing normal control is provided , and the control means includes the overspeed determination speed, the overspeed prevention fuel cut speed, the overspeed prevention fuel cut return speed, The overheat prevention apparatus for a vehicle engine, wherein the overspeed return determination rotational speed is set to increase as the vehicle speed of the vehicle increases . The overheat prevention device for a vehicle engine according to claim 1, wherein the control means is provided with the over-rotation determination time set so as to increase as the vehicle speed increases .

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