Nozzle opening control device

Abstract

To suppress deterioration of fuel economy.SOLUTION: A nozzle opening control device 1 for controlling a nozzle opening of a variable nozzle turbocharger 3 mounted to a vehicle 2 includes: an idling state determination section 11 that determines whether or not an engine 6 of the vehicle 2 is in an idling state; a long-term vehicle stop state determination section 14 that determines whether or not the vehicle 2 is in a long-term vehicle stop state where it cannot start immediately; and a nozzle opening control section 15 that controls a nozzle opening of the variable nozzle turbocharger 3. When the idling state determination section 11 determines that the engine 6 is in the idling state and the long-term vehicle stop state determination section 14 determines that the vehicle is in the long-term vehicle stop state, the nozzle opening control section 15 increases the nozzle opening.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a nozzle opening control device that controls the nozzle opening of a variable nozzle turbocharger mounted on a vehicle. [Background technology]

[0002] Conventionally, a variable nozzle turbocharger equipped with a variable nozzle for varying the flow rate of exhaust gas flowing into the turbine has been known as a turbocharger mounted on a vehicle (see, for example, Patent Document 1). In a vehicle equipped with a variable nozzle turbocharger, when the engine is at low speed, such as idling, the nozzle opening of the variable nozzle turbocharger is reduced to increase the flow rate of exhaust gas flowing into the turbine in preparation for the next acceleration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-150271 Summary of the Invention [Problem to be solved by the invention]

[0004] However, reducing the nozzle opening of a variable nozzle turbocharger increases pumping loss, resulting in a problem of worsening fuel economy.

[0005] Therefore, an object of the present invention is to provide a nozzle opening control device that can suppress deterioration of fuel efficiency. [Means for solving the problem]

[0006] The nozzle opening control device of the present invention is a nozzle opening control device that controls the nozzle opening of a variable nozzle turbocharger mounted on a vehicle, and is equipped with an idling state determination unit that determines whether the vehicle's engine is in an idling state, a long-term stationary state determination unit that determines whether the vehicle is in a long-term stationary state where it cannot start immediately, and a nozzle opening control unit that controls the nozzle opening of the variable nozzle turbocharger, and the nozzle opening control unit increases the nozzle opening when the idling state determination unit determines that the engine is in an idling state and the long-term stationary state determination unit determines that the vehicle is in a long-term stationary state.

[0007] When the engine is idling and the vehicle is parked for a long period of time, there is little need to prepare for the next acceleration. Therefore, this nozzle opening control device increases the nozzle opening of the variable nozzle turbocharger when the engine is idling and the vehicle is parked for a long period of time. This reduces pumping losses and can prevent a deterioration in fuel efficiency.

[0008] The long-term stop state determination unit may determine that the vehicle is in a long-term stop state when the vehicle's shift position is in a parking position. When the vehicle's shift position is in the parking position, it is considered that the driver will not immediately start the vehicle. Therefore, this nozzle opening control device can appropriately determine that the vehicle is in a long-term stop state by determining that the vehicle is in a long-term stop state when the vehicle's shift position is in the parking position.

[0009] The long-term stop state determination unit may determine that the vehicle is in a long-term stop state when the parking brake of the vehicle is applied. When the parking brake of the vehicle is applied, it is considered that the driver will not immediately start the vehicle. Therefore, this nozzle opening control device can appropriately determine that the vehicle is in a long-term stop state by determining that the vehicle is in a long-term stop state when the parking brake of the vehicle is applied. [Effects of the Invention]

[0010] According to the present invention, deterioration of fuel economy can be suppressed. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram showing a nozzle opening control device according to an embodiment; [Figure 2] 1 is a schematic diagram showing the engine and surroundings of a vehicle equipped with a nozzle opening control device according to an embodiment; [Figure 3] 10 is a graph showing an example of the relationship between nozzle opening and pumping loss. [Figure 4] 10 is a graph showing an example of the relationship between the nozzle opening degree and the fuel consumption amount. [Figure 5] 4 is a flowchart showing an example of a processing operation of a nozzle opening control device. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements will be designated by the same reference numerals, and redundant description will be omitted.

[0013] FIG. 1 is a block diagram showing a nozzle opening control device 1 according to an embodiment. FIG. 2 is a schematic diagram showing the engine 6 and its surroundings of a vehicle 2 equipped with the nozzle opening control device 1 according to an embodiment. As shown in FIGS. 1 and 2, the nozzle opening control device 1 according to this embodiment controls the nozzle opening of a variable nozzle turbocharger 3 equipped on the vehicle 2. The nozzle opening control device 1 is equipped on the vehicle 2 together with the variable nozzle turbocharger 3. The variable nozzle turbocharger 3 is a turbocharger equipped with a variable nozzle 5 for varying the flow speed of exhaust gas flowing into a turbine 4.

[0014] The nozzle opening control device 1 is, for example, an electronic control unit (ECU) having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. In the nozzle opening control device 1, for example, a program stored in the ROM is loaded into the RAM and executed by the CPU, thereby performing various controls. The nozzle opening control device 1 may be configured by a single electronic control unit or by multiple electronic control units.

[0015] The nozzle opening control device 1 includes an idling state determination unit 11 , a shift position detection unit 12 , a parking brake operation detection unit 13 , a long-term stationary state determination unit 14 , and a nozzle opening control unit 15 .

[0016] The idling state determination unit 11 determines whether or not the engine 6 of the vehicle 2 is idling. Whether or not the engine 6 is idling can be determined based on control information from an engine ECU that controls fuel injection of the engine 6, for example.

[0017] The shift position detection unit 12 detects the shift position of the vehicle 2. The shift position detection unit 12 detects the parking position, neutral position, drive position, reverse position, etc. The shift position can be detected, for example, based on the detection result of a shift position sensor that detects the shift position.

[0018] The parking brake operation detection unit 13 detects the operation state of the parking brake (not shown) of the vehicle 2. The parking brake operation detection unit 13 detects a state in which the parking brake is applied and a state in which the parking brake is not applied as the operation state of the parking brake. The operation state of the parking brake can be detected, for example, based on the detection result of a brake sensor that detects the operation state of the parking brake.

[0019] The long-term parked state determination unit 14 determines whether the vehicle 2 is in a long-term parked state in which it cannot be started immediately. The long-term parked state includes a state in which the shift position of the vehicle 2 is in the parking position, a state in which the parking brake of the vehicle 2 is engaged, and the like. When the shift position of the vehicle 2 is in the parking position, the driver cannot start the vehicle 2 unless he or she depresses the foot brake to change the shift position from the parking position to the drive position. Furthermore, when the parking brake of the vehicle 2 is engaged, the driver cannot start the vehicle 2 unless he or she releases the parking brake.

[0020] Therefore, the long-term stop state determination unit 14 determines that the vehicle 2 is in a long-term stop state, for example, when the shift position detection unit 12 detects that the shift position of the vehicle 2 is in the parking position, or when the parking brake operation detection unit 13 detects that the parking brake of the vehicle 2 is operating. On the other hand, the long-term stop state determination unit 14 determines that the vehicle 2 is not in a long-term stop state, for example, when the shift position detection unit 12 does not detect that the shift position of the vehicle 2 is in the parking position, and the parking brake operation detection unit 13 does not detect that the parking brake of the vehicle 2 is operating.

[0021] The nozzle opening control unit 15 controls the nozzle opening of the variable nozzle turbocharger 3. The nozzle opening is the opening of the variable nozzle 5. Specifically, the nozzle opening control unit 15 controls the nozzle opening of the variable nozzle turbocharger 3 by controlling the drive of an actuator (not shown) that changes the opening of the variable nozzle 5.

[0022] For example, when the engine 6 is rotating at low speeds, the nozzle opening control unit 15 reduces the nozzle opening of the variable nozzle turbocharger 3 (displaces the variable nozzle 5 toward the throttling side). This speeds up the flow of exhaust gas, allowing the turbine 4 to rotate even when the engine 6 is rotating at low speeds, and preparing for the next acceleration. On the other hand, when the engine 6 is rotating at high speeds, the nozzle opening control unit 15 increases the nozzle opening of the variable nozzle turbocharger 3 (displaces the variable nozzle 5 toward the opening side). This makes it possible to prevent the variable nozzle 5 from obstructing the flow of exhaust gas.

[0023] Incidentally, when the engine 6 is at low speed, including idling, the nozzle opening of the variable nozzle turbocharger 3 is reduced in preparation for the next acceleration, but reducing the nozzle opening of the variable nozzle turbocharger 3 increases pumping loss and worsens fuel economy. On the other hand, when the engine 6 is idling and the vehicle 2 is parked for a long period of time, there is little need to prepare for the next acceleration.

[0024] Therefore, when the idling state determination unit 11 determines that the engine 6 is in an idling state and the long-term parked state determination unit 14 determines that the vehicle 2 is in a long-term parked state, the nozzle opening control unit 15 increases the nozzle opening of the variable nozzle turbocharger 3. Note that the idling state of the engine 6 is also a low-speed state of the engine 6, so when the idling state determination unit 11 determines that the engine 6 is in an idling state, the nozzle opening of the variable nozzle turbocharger 3 has been reduced by the control of the nozzle opening control unit 15 even before the determination. Therefore, when the idling state determination unit 11 determines that the engine 6 is in an idling state and the long-term parked state determination unit 14 determines that the vehicle 2 is in a long-term parked state, the nozzle opening of the variable nozzle turbocharger 3, which has been reduced, is increased.

[0025] When increasing the nozzle opening of the variable nozzle turbocharger 3, the nozzle opening control unit 15 may or may not fully open the nozzle opening of the variable nozzle turbocharger 3. FIG. 3 is a graph showing an example of the relationship between the nozzle opening and the pumping loss. FIG. 4 is a graph showing an example of the relationship between the nozzle opening and the fuel consumption. As shown in FIGS. 3 and 4, when the nozzle opening of the variable nozzle turbocharger 3 increases to a certain extent, the increase in the pumping loss and the increase in the fuel consumption also plateau. For this reason, when increasing the nozzle opening of the variable nozzle turbocharger 3, the nozzle opening control unit 15 preferably increases the nozzle opening of the variable nozzle turbocharger 3 up to the nozzle opening at which the increases in the pumping loss and the fuel consumption plateau. The nozzle opening at which the increases in the pumping loss and the fuel consumption plateau varies depending on the type of variable nozzle turbocharger 3, the layout of the exhaust pipe, the types of parts used, etc. For this reason, it is possible to determine the nozzle opening at which the increase in pumping loss and fuel consumption reaches a plateau through prior experiments, simulations, etc., and when increasing the nozzle opening of the variable nozzle turbocharger 3, increase the nozzle opening of the variable nozzle turbocharger 3 up to this nozzle opening.

[0026] Next, an example of the processing operation of the nozzle opening control device 1 will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the processing operation of the nozzle opening control device 1.

[0027] 5, first, the nozzle opening control device 1 determines whether the engine 6 is in an idling state (step S1). In step S1, if the idling state determination unit 11 determines that the engine 6 is in an idling state, the nozzle opening control device 1 determines that the engine 6 is in an idling state, and if the idling state determination unit 11 determines that the engine 6 is not in an idling state, the nozzle opening control device 1 determines that the engine 6 is not in an idling state. If the nozzle opening control device 1 determines that the engine 6 is not in an idling state (step S1: NO), the nozzle opening control device 1 ends the processing once and repeats the process again from step S1.

[0028] If it is determined that the engine 6 is in an idling state (step S1: YES), the nozzle opening control device 1 determines whether or not the vehicle 2 is in a long-term parked state (step S2). In step S2, if the long-term parked state determination unit 14 determines that the vehicle 2 is in a long-term parked state, the nozzle opening control device 1 determines that the vehicle 2 is in a long-term parked state, and if the long-term parked state determination unit 14 determines that the vehicle 2 is not in a long-term parked state, the nozzle opening control device 1 determines that the vehicle 2 is not in a long-term parked state. If it is determined that the vehicle 2 is not in a long-term parked state (step S2: NO), the nozzle opening control device 1 ends the processing once and repeats the process again from step S1.

[0029] If it is determined that the vehicle 2 is in a long-term parked state (step S2: YES), the nozzle opening control device 1 increases the nozzle opening of the variable nozzle turbocharger 3 (step S3). Thereafter, the nozzle opening control device 1 maintains the increased nozzle opening of the variable nozzle turbocharger 3 until the vehicle 2 is no longer in a long-term parked state (step S4).

[0030] When it is determined that the vehicle 2 is no longer in a long-term parked state (step S4: NO), the nozzle opening control device 1 returns the nozzle opening of the variable nozzle turbocharger 3 to its original state (step S5).Then, the nozzle opening control device 1 temporarily ends the processing and repeats the process from step S1 again.

[0031] As described above, the nozzle opening control device 1 according to this embodiment increases the nozzle opening of the variable nozzle turbocharger 3 when the engine 6 is idling and the vehicle 2 is parked for an extended period of time. This reduces pumping loss, making it possible to prevent deterioration in fuel economy.

[0032] Furthermore, in this nozzle opening control device 1, it is possible to appropriately determine whether the vehicle 2 is in a long-term parked state by determining that the vehicle 2 is in a long-term parked state when the shift position of the vehicle 2 is in the parking position.

[0033] Furthermore, in this nozzle opening control device 1, by determining that the vehicle 2 is in a long-term parked state when the parking brake of the vehicle 2 is applied, it is possible to appropriately determine whether the vehicle is in a long-term parked state.

[0034] The above describes an embodiment of the present invention, but the present invention is not limited to the above embodiment, and may be modified or applied to other things within the scope that does not change the gist described in each claim. [Explanation of symbols]

[0035] 1...Nozzle opening control device, 2...Vehicle, 3...Variable nozzle turbocharger, 4...Turbine, 5...Variable nozzle, 6...Engine, 11...Idling state determination unit, 12...Shift position detection unit, 13...Parking brake operation detection unit, 14...Long-term stationary state determination unit, 15...Nozzle opening control unit.

Claims

1. A nozzle opening control device that controls a nozzle opening of a variable nozzle turbocharger mounted on a vehicle, an idling state determination unit that determines whether the engine of the vehicle is idling; a long-term stoppage state determination unit that determines whether the vehicle is in a long-term stoppage state in which the vehicle cannot immediately start; a nozzle opening control unit that controls the nozzle opening of the variable nozzle turbocharger, the nozzle opening control unit increases the nozzle opening until an increase in pumping loss and an increase in fuel consumption reach a ceiling when the idling state determination unit determines that the engine is in the idling state and the long-term stationary state determination unit determines that the vehicle is in the long-term stationary state. Nozzle opening control device.

2. the long-term stop state determination unit determines that the vehicle is in the long-term stop state when a shift position of the vehicle is a parking position; The nozzle opening control device according to claim 1 .

3. the long-term parked state determination unit determines that the vehicle is in the long-term parked state when a parking brake of the vehicle is activated; The nozzle opening control device according to claim 1 or 2.

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