JP4934084B2 - Warm-up acceleration control device for internal combustion engine - Google Patents

Description

  The present invention relates to a warm-up promotion control device for an internal combustion engine that controls an exhaust brake to promote warm-up of the engine.

  2. Description of the Related Art Conventionally, a warm-up promotion control device for an internal combustion engine that controls exhaust brake to promote engine warm-up is known. In such a warm-up promotion control device, the warm-up region using the exhaust brake is defined based on the relationship between the engine speed and the engine torque, and the warm-up using the exhaust brake is performed only within this region. Is called.

That is, as shown in FIG. 6, when the engine speed is taken on the horizontal axis and the engine torque is taken on the vertical axis, warm-up using the exhaust brake is performed only in the region C in the figure, thereby improving the durability of the engine. Is maintained. The curve a indicates a boundary line where the engine durability deteriorates, and the engine durability deteriorates above the boundary line.
Japanese Utility Model Publication No. 60-108734 Japanese Utility Model Publication No. 60-108735 Japanese Utility Model Publication No. 63-75538

  However, in the conventional warm-up acceleration control device, the operating range of the exhaust brake is limited to the region C in consideration of the durability of the engine, and the region D is excluded from the operating range, so that sufficient warm-up performance is obtained. There was a problem that I could not.

  The present invention has been made to solve such a conventional problem, and it is an object of the present invention to provide a warm-up promotion control device for an internal combustion engine that can greatly increase the operating range of an exhaust brake.

  An internal combustion engine warm-up promotion control device according to claim 1 is an internal-combustion engine warm-up promotion control device that controls exhaust brake to promote engine warm-up. And a second map that defines exhaust pressure corresponding to the region and that does not impair the durability of the engine. The exhaust brake is turned off when an exhaust pressure input from an exhaust pressure sensor for measuring pressure exceeds an exhaust pressure defined in the second map.

  The internal combustion engine warm-up promotion control device according to claim 2 is the internal combustion engine warm-up promotion control device according to claim 1, wherein the opening degree of the exhaust shutter of the exhaust brake is variable, and the engine speed is low. The opening of the exhaust shutter is reduced in the region.

  The internal combustion engine warm-up promotion control device according to claim 3 is the internal combustion engine warm-up promotion control device according to claim 1 or 2, wherein the exhaust pressure sensor controls the pressure at the inlet of the turbocharger of the engine. It is characterized by measuring.

  In the warm-up promotion control apparatus for an internal combustion engine according to claim 1, a plurality of regions for warm-up by the exhaust brake are defined in the first map based on the relationship between the engine speed and the engine torque. The second map defines an exhaust pressure that does not impair the durability of the engine corresponding to the region. When the exhaust pressure input from the exhaust pressure sensor that measures the exhaust pressure of the engine exceeds the exhaust pressure defined in the second map, the exhaust brake is turned off.

  In other words, in the present invention, if the exhaust pressure of the engine exceeds a predetermined exhaust pressure, the exhaust brake is automatically turned off. Therefore, even if the operating range of the exhaust brake is widened, the engine torque remains in the engine durability. The value will not be damaged. Therefore, the operating range of the exhaust brake can be greatly increased as compared with the prior art.

  In the internal combustion engine warm-up promotion control apparatus according to the second aspect, since the opening degree of the exhaust shutter of the exhaust brake is made variable, the strength of the exhaust brake can be easily increased or decreased. Moreover, since the opening degree of the exhaust shutter is reduced and the strength of the exhaust brake is increased in a region where the engine speed is low, the warm-up performance can be improved.

  In the internal combustion engine warm-up promotion control apparatus according to the third aspect, the exhaust pressure sensor measures the pressure at the inlet of the turbocharger of the engine, so that the exhaust pressure of the engine can be reliably measured.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an engine and an exhaust system to which an embodiment of a warm-up promotion control device for an internal combustion engine of the present invention is applied. In this embodiment, the present invention is applied to a truck diesel engine.

  In FIG. 1, the code | symbol 11 has shown the engine. A turbocharger 15 is provided in the exhaust manifold 13 of the engine 11. An exhaust pressure sensor 17 that measures the exhaust pressure of the engine 11 is provided at the inlet of the turbocharger 15. The engine 11 is provided with a temperature sensor 19 that measures the temperature of cooling water that cools the engine 11.

  An exhaust system 21 that exhausts exhaust gas from the engine 11 is connected to the engine 11. The exhaust gas from the engine 11 is purified by the catalytic converter 23, then flows into the muffler 29 through the front tube 25 and the exhaust pipe 27, is silenced, and is discharged to the outside.

  In FIG. 1, the code | symbol 31 has shown the exhaust brake. The exhaust brake 31 has an exhaust shutter 33 and an actuator 35. The exhaust shutter 33 is provided between the front tube 25 and the exhaust pipe 27. The opening degree of the exhaust shutter 33 is variable. The actuator 35 changes the opening degree of the exhaust shutter 33.

  In FIG. 1, reference numeral 37 indicates a control device that controls the exhaust brake 31. An ECU is used for the control device 37. The control device 37 is provided with a brake switch 39 and a warm-up switch 41. The brake switch 39 and the warm-up switch 41 are provided on the instrument panel of the driver's seat.

  The control device 37 performs the operation of the normal exhaust brake 31 that performs the brake operation on the vehicle using the exhaust shutter 33 when the brake switch 39 is on. At this time, the exhaust brake 31 is operated only when the accelerator is off.

  The control device 37 performs a warm-up operation for quickly increasing the temperature of the coolant of the engine 11 when the warm-up switch 41 is on. In this warm-up operation, the exhaust brake 31 is also activated when the accelerator is on.

  The control device 37 receives an engine control signal S such as the engine speed and the amount of fuel to be injected. Then, the engine torque is calculated based on the engine control signal S. Further, the control device 37 inputs a cooling water temperature signal from the temperature sensor 19 and inputs an exhaust pressure of the engine 11 from the exhaust pressure sensor 17.

  The control device 37 has a first map 43 and a second map 45.

  The first map 43 defines a plurality of regions for warming up by the exhaust brake 31 based on the relationship between the engine speed and the engine torque. The second map 45 defines an exhaust pressure that does not impair the durability of the engine 11 corresponding to the above-described region.

  In this embodiment, as shown in FIG. 2, when the engine speed is taken on the horizontal axis and the engine torque is taken on the vertical axis, warm-up using the exhaust brake 31 is performed in the regions A and B in the figure. Region B corresponds to a region where the engine speed in region C shown in FIG. 6 is 1500 rpm or more. Region A is when the engine speed is less than 1500 rpm, and the operating range of the exhaust brake 31 has increased to the region D in the chain line in FIG. A curve a indicates a boundary line where the durability of the engine 11 deteriorates, and the durability of the engine 11 deteriorates above the boundary line. In the region A, the opening degree of the exhaust shutter 33 is made smaller than that in the region B.

  FIG. 3 shows an example of the first map 43. The time when the engine speed is less than 1500 rpm corresponds to the region A in FIG. In this region A, the exhaust brake 31 is operable up to an engine torque of 60 Nm. The time when the engine speed is 1500 to 2000 rpm corresponds to the region B in FIG. In this region B, the exhaust brake 31 is operable up to an engine torque of 40 Nm.

  FIG. 4 shows an example of the second map 45. The time when the engine speed is less than 1500 rpm corresponds to the region A in FIG. In this region A, the exhaust brake 31 is operable up to an engine torque of 60 Nm. Region A is divided into a plurality of regions corresponding to the engine speed and engine torque. And the exhaust pressure which does not impair the durability of the engine 11 is prescribed | regulated to the several area | region. The exhaust pressure increases as the engine torque increases.

  The time when the engine speed is 1500 to 2000 rpm corresponds to the region B in FIG. In this region B, the exhaust brake 31 is operable up to an engine torque of 40 Nm. Region B is divided into a plurality of regions corresponding to the engine speed and engine torque. And the exhaust pressure which does not impair the durability of the engine 11 is prescribed | regulated to the several area | region. The exhaust pressure increases as the engine torque increases.

  Hereinafter, the operation of the above-described internal combustion engine warm-up promotion control apparatus will be described with reference to the flowchart shown in FIG. This operation is performed on the assumption that the warm-up switch 41 is turned on.

  Step S1: It is determined whether or not the temperature of the cooling water of the engine 11 is lower than the target temperature. This determination is made by inputting a temperature signal from the temperature sensor 19 and comparing it with a preset target temperature. The target temperature is set to a temperature at which the room can be heated with cooling water, for example.

  Step S2: When the temperature of the cooling water of the engine 11 is lower than the target temperature, it is determined whether or not the exhaust pressure of the engine 11 is lower than a specified value. This determination is made by inputting an exhaust pressure signal from the exhaust pressure sensor 17 and comparing it with an exhaust pressure that does not impair the durability of the engine 11 defined in the second map 45. For example, in the second map 45, when the engine speed is 1000 rpm and the engine torque is 60 Nm, the exhaust pressure is set to less than 3 atmospheres. Accordingly, when the exhaust pressure from the exhaust pressure sensor 17 is less than 3 atmospheres, it is determined that the exhaust pressure of the engine 11 is less than a specified value, and when it is 3 atmospheres or more, it is determined that the exhaust pressure of the engine 11 exceeds the specified value. To do.

  Step S3: When the exhaust pressure of the engine 11 is less than the specified value, the exhaust brake 31 is operated. In this case, even if the exhaust brake 31 is operated, the durability of the engine 11 is not impaired.

  Step S4: It is determined whether or not the coolant temperature of the engine 11 is equal to or higher than a target temperature. This determination is made by inputting a temperature signal from the temperature sensor 19 and comparing it with a preset target temperature.

  Step S5: When the cooling water temperature of the engine 11 is equal to or higher than the target temperature, the operation of the exhaust brake 31 is stopped.

  In the above-described warming-up acceleration control device for an internal combustion engine, the exhaust brake 31 is automatically turned off when the exhaust pressure of the engine 11 exceeds a predetermined exhaust pressure, so the operating range of the exhaust brake 31 is expanded. However, the engine torque does not become a value that impairs the durability of the engine 11. Therefore, the operating range of the exhaust brake 31 can be greatly increased as compared with the conventional case. And by increasing the operating range of the exhaust brake 31, it is possible to improve the warm-up performance and to quickly raise the temperature of the cooling water of the engine 11.

  Moreover, since the opening degree of the exhaust shutter 33 of the exhaust brake 31 is made variable, the strength of the exhaust brake 31 can be easily increased or decreased. Further, since the opening degree of the exhaust shutter 33 is reduced and the strength of the exhaust brake 31 is increased in a region where the engine speed is low, the warm-up performance can be further improved.

Further, since the exhaust pressure sensor 17 measures the pressure at the inlet of the turbocharger 15 of the engine 11, the exhaust pressure of the engine 11 can be reliably measured.
(Supplementary items of the embodiment)
As mentioned above, although this invention was demonstrated by embodiment mentioned above, the technical scope of this invention is not limited to embodiment mentioned above, For example, the following forms may be sufficient.

  (1) In the above-described embodiment, the example in which the exhaust pressure sensor 17 is provided in the turbocharger 15 has been described. However, the exhaust pressure sensor 17 may be provided in the exhaust manifold 13.

  (2) In the above-described embodiment, the example in which the opening degree of the exhaust brake 31 is made variable has been described, but it is not always necessary to make it variable.

It is explanatory drawing which shows the engine provided with one Embodiment of the warming-up promotion control apparatus of this invention, and an exhaust system. It is explanatory drawing which shows the operating range of the exhaust brake by the warming-up promotion control apparatus of FIG. It is explanatory drawing which shows an example of a 1st map. It is explanatory drawing which shows an example of a 2nd map. It is explanatory drawing which shows operation | movement of the warming-up promotion control apparatus of FIG. It is explanatory drawing which shows the operating range of the exhaust brake by the conventional warming-up promotion control apparatus.

Explanation of symbols

11 Engine 15 Turbocharger 17 Exhaust pressure sensor 19 Temperature sensor 21 Exhaust system 31 Exhaust brake 33 Exhaust shutter 35 Actuator 37 Controller 41 Warm-up switch 43 First map 45 Second map

Claims (3)

In the warm-up promotion control device for an internal combustion engine that controls the exhaust brake to promote the warm-up of the engine,
A first map that defines a plurality of regions for warm-up by the exhaust brake based on the relationship between engine speed and engine torque;
A second map that defines exhaust pressure corresponding to the region and does not impair the durability of the engine;
An internal combustion engine that turns off the exhaust brake when an exhaust pressure input from an exhaust pressure sensor that measures an exhaust pressure of the engine exceeds an exhaust pressure defined in the second map. Warm-up acceleration control device. In the internal combustion engine warm-up promotion control device according to claim 1,
A warm-up promotion control device for an internal combustion engine, wherein an opening degree of an exhaust shutter of the exhaust brake is variable and the opening degree of the exhaust shutter is reduced in a region where the engine speed is low. In the warm-up promotion control device for an internal combustion engine according to claim 1 or 2,
The warm-up promotion control device for an internal combustion engine, wherein the exhaust pressure sensor measures a pressure at an inlet of a turbocharger of the engine.

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