JPH06317166A - Supercharging pressure control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent sudden fluctuation of torque by providing a renewal means for renewing temperature parameters for controlling supercharging pressure and a control means for controlling supercharging pressure based on the supercharging-pressure control temperature parameters. CONSTITUTION:In an intake passage 1 connected to an internal combustion engine main body E, a mechanical supercharger SC, an intercooler IC and a throttle valve 4 are interposed in that order from an air cleaner A at the upstream end of the passage 1 to the downstream side. An intake temperature sensor 23 for detecting intake temperature TA, a compressed air temperature sensor 24 for detecting the temperature T2 of compressed air, and an intercooler water temperature sensor 25 are disposed in the respective portions of the intake passage 1 and the detection signals of the sensors are input to a control means C. The control means C determines whether or not the temperatures detected are within prescribed ranges in which they should be if the fluctuations of the temperatures detected are normal, and, when determining that the temperatures are out of the prescribed ranges, restricts renewal of temperature parameters for controlling supercharging pressure. Therefore, sudden change in desired supercharging pressure resulting from abnormality of the temperature sensors, and thus sudden fluctuation of torque, can surely be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to supercharging pressure control in an internal combustion engine equipped with a supercharger.

[0002]

2. Description of the Related Art As a conventional example relating to supercharging pressure control of a supercharger, there is an example described in JP-A-57-157016. In the same example, a target supercharging pressure of a turbocharged engine is controlled by intake air temperature, engine water temperature, etc. The method of making the decision is shown.

For example, the intake air temperature is detected, a table is searched from the detected temperature to find a correction rate for correcting the basic value of the boost pressure, and the target boost pressure is determined by the correction rate to control the boost pressure. Is going. When the intake air temperature is higher than a certain temperature, the correction rate for lowering the target supercharging pressure is selected and controlled.

[0004]

[Problems to be solved] As described above, conventionally, since the correction rate for correcting the target supercharging pressure is obtained by directly searching the table from the intake air temperature, when the temperature sensor is abnormal, for example, disconnection or When a short circuit, an abnormality in the sensor itself, or noise occurs, a table is searched for the correction rate based on the abnormal signal, and the boost pressure is controlled by the correction rate.

Therefore, if such an abnormality occurs during supercharging and the target supercharging pressure changes or the supercharging is stopped, a rapid torque change may occur. The present invention has been made in view of the above points, and an object thereof is to provide a supercharging pressure control device that does not cause a rapid torque change even if an abnormality occurs in a temperature sensor.

[0006]

In order to achieve the above object, according to the present invention, in an internal combustion engine equipped with a supercharger, a temperature sensor for detecting a temperature at a required location and the temperature sensor detect the temperature. Update means for updating the supercharging pressure control temperature parameter value based on the temperature, control means for controlling the supercharging pressure based on the supercharging pressure control temperature parameter value, and fluctuations in the detected temperature are within a predetermined range. Determining means for determining whether or not the variation of the detected temperature is out of a predetermined range, and limiting means for limiting update of the supercharging pressure control temperature parameter value by the updating means. And a supercharging pressure control device for an internal combustion engine including.

If the temperature detected by the temperature sensor is normal, it does not fluctuate abruptly and significantly, and the fluctuation range is limited. Therefore, it is judged whether or not the detected temperature is within a predetermined range that will be contained if the fluctuation of the detected temperature is normal,
When it is determined that the temperature is out of the predetermined range, the update of the supercharging pressure control temperature parameter value is limited to prevent a sudden change in the target supercharging pressure due to an abnormality in the temperature sensor, and thus a sudden change in the torque.

A second invention is an internal combustion engine having an intercooler and a supercharger having an intercooler water pump, and an intercooler water temperature sensor for detecting a temperature of cooling water of the intercooler, and the intercooler. Updating means for updating the supercooling pressure control intercooler water temperature parameter value based on the temperature detected by the water temperature sensor; control means for controlling the supercharging pressure based on the supercharging pressure control intercooler water temperature parameter value; Intercooler A determination means for determining whether or not the variation of the water temperature is within a predetermined range, a state change detection means for detecting a state change of the intercooler water pump, and an intercooler detected by the state change detection means. Range changing means for changing the predetermined range according to the state of the water pump for use, When the determination means determines that the variation of the output intercooler water temperature is outside the predetermined range, the internal combustion engine is provided with a limiting means for limiting the update of the supercharging pressure control intercooler water temperature parameter value by the updating means. It was a boost pressure control device.

Since there is a possibility that the intercooler water temperature actually changes when the water pump starts to be driven, when the water pump is stopped, and when the state changes such as a sudden change in the number of revolutions, it is determined whether or not the parameters are updated according to the state change of the water pump. By changing the predetermined range of, it is possible to reliably prevent a rapid change in torque due to an abnormality in the intercooler water temperature sensor.

[0010]

EXAMPLES An example of the present invention shown in FIGS. 1 to 4 will be described below. FIG. 1 is a control block diagram of an intake system of an internal combustion engine of this embodiment.

An intake passage 1 and an exhaust passage 2 are connected to the engine body E, and a mechanical supercharger SC, an intercooler IC, and a throttle valve are sequentially provided in the intake passage 1 from an air cleaner A at an upstream end thereof to a downstream side. 4 is installed. A bypass passage 3 that bypasses the mechanical supercharger SC and the intercooler IC is connected to the intake passage 1, and a bypass valve 5 is provided in the bypass passage 3.

A control chamber 6 for changing the internal compression ratio is integrally attached to the mechanical supercharger SC, and a conduit 7 is provided from the control chamber 6.
Are extended and connected to the electromagnetic switching valve 8. On the other hand, a conduit 9 branches off from a junction with the bypass passage 3 of the intercooler IC and is connected to the electromagnetic switching valve 8.

The electromagnetic switching valve 8 is connected with a conduit 9 and a passage 11 communicating with the atmosphere via an air cleaner 10.
The state in which the atmospheric pressure is introduced from the air cleaner 10 via the passage 11 and the state in which the supercharging pressure in the intake passage 1 is introduced via the conduit 9 is switched to the conduit 7 leading to the control chamber 6 of the mechanical supercharger SC. be able to.

When the atmosphere is introduced into the control room 6, the mechanical supercharger SC has a low compression ratio, and when the supercharging pressure is introduced, the mechanical supercharger SC has a high compression ratio. By-pass valve driving means for switching the electromagnetic switching valve 8 and opening / closing the bypass valve 5.
The operation of 12 is controlled by the control means C including a microcomputer.

The control means C receives detection signals from various sensors for judging the operating state of the engine.
First, the engine body E is provided with an engine speed sensor 20 along the crankshaft 13 to detect the engine speed N _E and send a detection signal to the control means C, and a throttle opening sensor 21 provided on the throttle valve 4 detection signal of the throttle opening theta _TH is sent to the control means C from the bypass opening theta _BP is further from the bypass opening sensor 22 provided in the bypass valve 5
Is sent to the control means C. A supercharging pressure sensor 19 is provided in the conduit 9 extending from the intake passage 1 to detect the supercharging pressure P ₂ and send it to the control means C.

Further, in the intake passage 1, an intake air temperature sensor 23 for detecting the intake air temperature T _A slightly upstream of the intake port of the engine body E, and an intercooler IC downstream of the mechanical supercharger SC.
A compressed air temperature sensor 24 for detecting the compressed air temperature T ₂ and an intercooler water temperature sensor 25 for detecting the intercooler water temperature T _WI are respectively arranged on the upstream side, and each detection signal is sent to the control means C. It is supposed to be entered.

The intercooler IC is provided with a cooling water circuit 26 independent of an engine cooling water passage (not shown), and the cooling water circuit 26 has an electric water pump 27 controlled by a control means C and a radiator. 28, the cooling water is circulated between the intercooler IC and the radiator 28 by the operation of the water pump 27, and the intercooler water temperature sensor 25 detects the water temperature of the circulating cooling water. .

The control means C controls the engine speed N _E , the throttle opening θ _TH , the boost pressure P ₂ and the bypass opening θ _BP.
Further, the intake air temperature T _A , the compressed air temperature T ₂ , and the intercooler water temperature T _WI are input and processed to operate the electromagnetic switching valve 8 and the bypass valve drive means 12 to perform supercharging pressure control.

At the same time, the control means C drives the water pump 27 to circulate the cooling water to cool the supercharged air when the intercooler water temperature T _WI detected by the intercooler water temperature sensor 25 exceeds the reference temperature. It is controlled to do.

On the other hand, the outline of the supercharging pressure control is to obtain the basic value of the target supercharging pressure from the operating conditions such as the engine speed N _E and the throttle opening θ _TH , while the intake air temperature T _A and the compressed air temperature T are calculated. ₂ ,
Temperature parameter values CT _A , CT for supercharging pressure control that are determined in advance by being associated with each other from the intercooler water temperature T <sub>WI
2. Calculate</sub> CT _WI , modify the basic value of the target boost pressure with the temperature parameter values CT _A , CT ₂ , CT _{WI for} boost pressure control to determine the final target boost pressure, and then set the target boost pressure. The bypass valve drive means 12 and the like are controlled to bring the pressure.

If an abnormality occurs in the temperature detecting sensors 23, 24, 25, the temperature parameter value for supercharging pressure control also shows an abnormal value, which changes the target supercharging pressure and causes the torque fluctuation. Become. Therefore, the control of this embodiment for avoiding such a problem will be described with reference to the flowchart of FIG.

First, in step 1, each temperature detecting sensor 23,
The supercharging control temperature parameter values CT _A , CT ₂ and CT _WI are updated from the latest input values T _A , T ₂ and T _WI from 24 and 25. Then, in a next step 2, and determines whether the boost condition by whether the boost pressure or P ₂ is greater than the predetermined pressure P _SC, when there is no smaller than the boost condition predetermined pressure P _SC is , Exit this routine.

On the other hand, in step 2, the supercharging pressure P ₂ is the predetermined pressure P _SC.
When it is determined that the state of supercharging is larger, the process proceeds to step 3, and it is determined whether or not the intake air temperature sensor 23 has a disconnection / short circuit. If there is no disconnection / short circuit, the process proceeds to step 4; Fly over to step 5.

In step 4, the previous value T of the intake air temperature T _A
It is determined whether or not the difference (variation width) between _An-1 and the current value T _An is larger than the predetermined value D ₁ , and if it is normal, the detected intake air temperature does not change significantly, so the fluctuation range is predetermined. Although it is smaller than the value D _1, it skips step 5 and proceeds to step 6, but if there is an abnormality, the detected intake air temperature may change greatly, and the fluctuation range exceeds the predetermined value D ₁ and proceeds to step 5.

In step 5, the previous value CT _An-1 is added to the current temperature parameter value CT _An for supercharging control so that the previous value is maintained and updating is limited. If it is determined in step 3 that there is a wire break / short circuit, the flow jumps to step 5 without checking the magnitude of the fluctuation range in step 4, so when there is a wire break / short circuit in the intake air temperature sensor 23, or a detection when the variation width of the temperature T _a is larger than a predetermined value D ₁ maintains the supercharge control temperature parameter value CT _an is the previous value, supercharging control that was updated in step 1 if all other normal of The temperature parameter value CT _A will be used.

In the next steps 6, 7 and 8, the compressed air temperature sensor 24 is controlled in the same manner as in steps 3, 4 and 5. That is, when the compressed air temperature sensor 24 is broken or short-circuited (step 6), or when the fluctuation range of the detected compressed air temperature T ₂ is larger than the predetermined value D ₂ (step 7), the supercharging control temperature parameter is set. The value CT _2n maintains the previous value CT _2n-1 (step 8), and otherwise, the updated value CT ₂ (step 1) is used.

When the next step 9 is entered, it is judged whether or not the intercooler water temperature sensor 25 has a wire break / short circuit. If there is a wire break / short circuit, the process jumps to step 15 and the intercooler water temperature parameter value for supercharging pressure control. Previous value CT to CT _{WIn
Insert WIn-1} to maintain the previous value and limit the update.

In step 9, the intercooler water temperature sensor
If it is determined that there is no disconnection or short circuit in 25, the process proceeds to step 10 and it is determined whether or not the state change has occurred in the intercooler water pump 27. That is, in step 10, is there a state change such as a change from stop to drive, a change from drive to stop, or a sudden change in the rotational speed of the water pump 27, or is the water pump 27 still in a steady state (including a stopped state)? Is determined.

[0029] The timer TmWP proceeds to step 11 if the steady state is determined whether it is 0 there is no state change, the previous value of the intercooler temperature T _WI proceeds to TmWP = 0 if the step 12 T _{WIN- It} is determined whether or not the difference (variation width) between ₁ and the current value T _WIn is larger than the predetermined value D ₃ , and if normal, it is smaller than the predetermined value D ₃ and skips step 15 to exit this routine and update in step 1. The intercooler water temperature parameter value for supercharging pressure control is used.

When the state of the water pump 27 changes, the process jumps from step 10 to step 13 to set the timer tmWP to a predetermined time, and then in the next step 14, the fluctuation range of the intercooler water temperature T _WI | T _WIn -T _{WIn -1} | it is determined whether or not larger than a predetermined value D _4. Predetermined value D here
₄ is a value larger than the predetermined value D _{3 used} as the reference for comparison in step 12.

That is, when the state of the water pump 27 changes, there is a possibility that the intercooler water temperature will fluctuate within a predetermined time thereafter, and if the intercooler water temperature sensor 25 is operating normally, the detected value will change to some extent. In order to determine an abnormality such as noise, the predetermined value D ₃ cannot be determined, and the predetermined value D ₄ larger than the predetermined value D ₃ is used as a reference.

After the state of the water pump 27 changes, step
The process proceeds from step 10 to step 11 and proceeds to step 14 until the timer tmWP set in step 13 becomes 0, and the timer tmWP is discriminated based on the large predetermined value D _4.
Is 0, the process proceeds to step 12 and the predetermined value D ₃ is used as a reference for determination. That is, when the state of the water pump 27 changes, it is discriminated based on the predetermined value D ₄ for a predetermined time thereafter.

In step 14, if the fluctuation range of the intercooler water temperature T _WI is smaller than the predetermined value D ₄ , it is normal and the routine directly exits to use the updated value for the supercooling pressure control intercooler water temperature parameter value CT _WI. On the contrary, if the fluctuation range of the intercooler water temperature T _WI is larger than the predetermined value D ₄ , abnormality such as noise is considered, and the process proceeds to step 15 and the previous value CT _{WIn-1 is} set to the supercooling control intercooler water temperature parameter value CT _WIn.
To maintain the value.

Thus, the intercooler water temperature sensor 25
The abnormality determination is performed more accurately by changing the predetermined values D ₃ and D ₄ which are the reference for the determination for a predetermined time after the state change of the water pump 27 and for other steady state. Since the fluctuation range of the intercooler water temperature T _WI is different between the start and stop of the water pump 27 among the state changes of the water pump 27, the predetermined value D ₄ may be changed. It is conceivable to set the predetermined value D ₄ to a large value while stopping at a large value.

As described above, in the supercharged state, when a detection signal which changes due to a cause other than the actual temperature change is input to any of the temperature sensors 23, 24, 25 due to an abnormality such as disconnection, short circuit or the like, Since the temperature parameter value for supercharging control is not updated to a value that changes drastically and is maintained at the previous value, a sudden torque change is not caused.

Focusing on, for example, the intake air temperature sensor 23, the correspondence between the change in the detected intake air temperature T _A and the supercharging pressure control temperature parameter CT _A will be described with reference to FIGS. 3 and 4. Figure 3 shows an example in which noise occurs, usually has risen boost pressure control temperature parameter value CT _A in response to increase of the intake air temperature T _A, the noise to the intake air temperature T _A If there is a protrusion, the fluctuation range of the intake air temperature T _A due to the protrusion exceeds the predetermined value D ₁ , so that the previous value of the temperature parameter value CT _A is maintained and does not change significantly. As a result, the temperature parameter value CT _A also rises to draw a smooth curve and prevent a sudden change in the target boost pressure to prevent a sudden change in torque.

FIG. 4 shows the state when the wire breakage occurs. At the time when the wire breakage occurs, the intake air temperature T _A fluctuates greatly and the temperature parameter value CT _A continues to be maintained at the previous value at approximately the same time. In the parameter value CT _A, the rising curve changes to a horizontal straight line to prevent torque fluctuation due to disconnection of the intake air temperature sensor 23.

After exiting the supercharging region, the temperature parameter value CT _A is controlled by a predetermined appropriate alternative value CT _AD and does not affect other processes. Even if the supercharging region lasts for a long time, other sensors may reduce the supercharging pressure.For example, if the supercooling is interrupted when the water temperature of the intercooler exceeds a predetermined value, it may impose a heavy burden on the engine. Absent.

Note that, once the temperature parameter value CT _A is maintained due to a disconnection or the like, once the temperature is out of the supercharging area, control is performed so that it will not enter the supercharging area again.

[0040]

According to the present invention, it is determined whether or not the detected temperature is within a predetermined range that would normally be contained if the variation of the detected temperature of the temperature sensor is normal. By limiting the update of the temperature parameter value for controlling the supercharging pressure, it is possible to prevent a sudden change in the target supercharging pressure due to an abnormality in the temperature sensor and thus a sudden change in the torque.

Further, since there is a possibility that the intercooler water temperature actually changes when the water pump starts to be driven, when the water pump is stopped, and when the state changes such as a sudden change in the number of revolutions, whether or not the parameters are updated depending on the state change of the water pump. By changing the predetermined range of the judgment, it is possible to accurately prevent the rapid change of the torque due to the abnormality of the intercooler water temperature sensor.

[Brief description of drawings]

FIG. 1 is a control configuration diagram of an intake system of an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a diagram showing a control flowchart of this embodiment.

FIG. 3 is a diagram showing an example of changes in a detected value of an intake air temperature sensor and a temperature parameter value for supercharging pressure control.

FIG. 4 is a diagram showing an example of another state.

[Explanation of symbols]

E ... Engine body, A ... Air cleaner, SC ... Mechanical turbocharger,
IC ... Ink cooler, C ... Control means, 1 ... Intake passage, 2
... Exhaust passage, 3 ... Bypass passage, 4 ... Throttle valve, 5
... by-pass valve, 6 ... control chamber, 7 ... conduit, 8 ... electromagnetic switching valve, 9 ... conduit, 10 ... air cleaner, 11 ... passage, 12 ... bypass valve drive means, 13 ... crank shaft, 19 ... supercharging pressure sensor, 20 ... Engine speed sensor, 21 ... Throttle opening sensor, 22 ... Bypass opening sensor, 23 ... Intake air temperature sensor, 24 ... Compressed air temperature sensor, 25 ... Intercooler water temperature sensor, 26 ... Cooling water circuit, 27 ... Water Pump, 28 ...
Radiator.

Claims (2)

[Claims] 1. An internal combustion engine equipped with a supercharger, a temperature sensor for detecting a temperature at a required location, and an updating means for updating a supercharging pressure control temperature parameter value based on the temperature detected by the temperature sensor. Control means for controlling the supercharging pressure based on the temperature parameter value for supercharging pressure control, judging means for judging whether or not the fluctuation of the detected temperature is within a predetermined range, and fluctuation of the detected temperature within a predetermined range. A supercharging pressure control device for an internal combustion engine, comprising: a limiting means for limiting the updating of the supercharging pressure control temperature parameter value by the updating means when the judging means determines that it is outside. 2. In an internal combustion engine having an intercooler and a supercharger equipped with a water pump for the intercooler, an intercooler water temperature sensor for detecting a temperature of cooling water of the intercooler, and an intercooler water temperature sensor for detecting the temperature of the cooling water. Updating means for updating the supercooling pressure control intercooler water temperature parameter value based on temperature, control means for controlling the supercharging pressure based on the supercharging pressure control intercooler water temperature parameter value, and fluctuation of the detected intercooler water temperature Is within a predetermined range, a state change detecting means for detecting a state change of the intercooler water pump, and a state of the intercooler water pump detected by the state change detecting means. Predetermined range changing means for changing the predetermined range according to And a limiting means for limiting the update of the supercharging pressure control intercooler water temperature parameter value by the updating means when the determining means determines that the fluctuation of the cooler water temperature is outside the predetermined range. Boost pressure control device for internal combustion engine.