JP2560501B2 - Supercharging pressure controller for vehicle exhaust turbocharged engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a supercharging pressure control device for a vehicle exhaust turbocharged engine.

[Prior Art] In a vehicle engine, particularly an automobile engine,
It is often found that an engine equipped with an exhaust turbocharger is used to measure the increase in output, but in this engine equipped with an exhaust turbocharger, the supercharging pressure may rise indefinitely as the engine exhaust gas flow rate increases. Therefore, conventionally, the waste gate valve provided in the exhaust bypass passage that bypasses the exhaust turbine is opened when the boost pressure exceeds the set value, and the rotation speed of the turbine, that is, the compressor is reduced to reduce the boost pressure. Attempts are made to keep the value below the set value. Recently, in order to further improve the engine performance, in the engine of this type, the above set value is variably set according to the operating state, that is, the rate of increase of the engine speed, the vehicle speed, and the gear position of the transmission. Various proposals to do have come to be seen.

For example, the invention described in Japanese Patent Laid-Open No. 1-318723 discloses a transient state in which the rate of increase in engine speed is high (for example,
In the 1st and 2nd speeds, when the throttle is fully opened), the supercharging pressure does not rise sufficiently and the increase in turbine speed is delayed.
In order to solve the problem that the target boost pressure cannot be obtained and the engine output decreases when the set boost pressure control similar to the steady state is performed in this transient state, the rate of increase in engine speed and the transmission The setting value of the supercharging pressure is variably set according to the gear position.

In detail, this conventional technique is such that the boost pressure control valve is controlled so that the target boost pressure is set in advance according to the engine speed, and as the rate of increase of the engine speed increases, Alternatively, when the gear position of the transmission is a lower gear, the control amount (duty ratio) of the boost pressure control valve is corrected to be larger, and when the rate of increase in engine speed is large, such as when the low gear of the transmission is used. Also, the delay in turbine speed increase is compensated, a sufficient supercharging pressure is secured, and output reduction is prevented.

[Problems to be Solved by the Invention]

In this conventional technique, as described above, when the low speed gear of the transmission is used, or when the rate of increase of the engine speed is large,
The target supercharging pressure is corrected to a high level to secure a sufficient supercharging pressure and prevent the engine output from decreasing.

However, in the conventional technology, when the low speed gear of the transmission is used, or when the rate of increase of the engine speed is large,
The target supercharging pressure is corrected to a high level to secure a sufficient supercharging pressure to prevent the engine output from decreasing. For example, the fuel used in the engine is a high octane fuel (high octane fuel) or a low octane fuel ( If a fuel different from the standard fuel type is used by mistake, the
There was a problem that supercharging pressure control could not be performed according to the fuel used.

Furthermore, in an engine in which a high octane number fuel is specified as the standard fuel, smooth driving may not be obtained if the boost pressure is too high at low speed during acceleration operation, especially for vehicle speed. To set the maximum boost pressure,
It has come to be required to properly control an engine in a vehicle.

[Means for solving the problem]

The present invention has been proposed in view of the above, and includes an engine mounted on a vehicle, a compressor installed in an intake passage of the engine, and a turbine installed in an exhaust passage of the engine to drive the compressor. And an exhaust turbocharger that pressurizes intake air supplied to the combustion chamber of the engine, and operates the exhaust turbocharger so that the intake pressure in the intake passage on the downstream side of the compressor is detected and the intake pressure becomes equal to or lower than a set pressure. A supercharging pressure control means for controlling, a fuel type determination means for determining whether or not the used fuel is a high octane fuel based on the fuel type information of the fuel used by the engine, a speed detection means for detecting the speed of the vehicle, Rotation speed detection means for detecting the engine rotation speed of the engine,
An automatic transmission with a fluid coupling which is interposed in the drive system of the vehicle and transmits the output of the engine, and when the fuel type determination means determines that the fuel used is other than a high octane fuel, the set pressure is set to the first value. And a setting pressure adjusting means for setting the setting pressure to a second setting value which is higher than the first setting value when it is determined that the fuel to be used is a high octane fuel. The set pressure adjusting means determines that the fuel used by the engine is a high octane fuel, and the speed of the vehicle detected by the speed detecting means is equal to or lower than the set vehicle speed and is detected by the rotational speed detecting means. When the speed is lower than the rotation speed, the set pressure is set to the first set value, and the speed of the vehicle detected by the speed detecting means is equal to or lower than the set vehicle speed and the rotation is performed. An intake pressure control device for an engine with an exhaust gas turbocharger for a vehicle, characterized in that the set pressure is set to the second set value when the set rotational speed detected by the detection means is exceeded. is there.

[Action]

According to the present invention, as the fuel type information of the fuel used by the engine and the operating state of the vehicle, the maximum boost pressure is determined in accordance with the vehicle speed or the gear position of the vehicle transmission indirectly indicating the vehicle speed state. The value is adjusted, and when the set pressure adjusting means determines that the used fuel is other than the high octane fuel, the set pressure is set to the first set value and the used fuel is the high octane fuel. When the determination is made, the set pressure is set to a second set value which is higher than the first set value, and it is further determined that the fuel used is a high octane fuel, and the vehicle is detected by the speed detecting means. Is set to a value other than the set vehicle speed and lower than the set rotation speed detected by the rotation speed detection means, the set pressure is set to the first set value and the speed detected by the speed detection means is set. The set pressure when the speed of the two is greater than the setting rotational speed detected by and the rotation speed detecting means below the set vehicle speed is set to the second set value.

Therefore, the supercharging pressure control means controls the operation of the exhaust turbocharger so as to be equal to or lower than the set pressure corresponding to each set value set by the set pressure adjusting means, so that the intake passage in the compressor downstream side is controlled. The maximum supercharging pressure of the intake pressure is adjusted according to the fuel type information of the fuel used by the engine and the operating state of the vehicle.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, an engine E mounted on an automobile (not shown) has an intake port and an exhaust port (not shown) that communicate with a combustion chamber 1 thereof, and the intake port communicates with the outside air via an intake manifold 2 and an intake passage 4. The exhaust port is communicated with the outside air via the exhaust manifold 6 and the exhaust passage 8. The arrows in the intake passage 4 and the exhaust passage 8 indicate the gas flow direction.

Further, the intake passage 4 has an air cleaner in order from the upstream side.
10, a compressor 14 of the turbocharger 12, an intercooler 16, and a throttle valve 18 connected to an accelerator pedal operated by a driver are provided, and the exhaust passage 8 has
A turbine 20 of the turbocharger 12 is provided, and a catalytic converter and a muffler (not shown) are provided in the exhaust passage 8 on the downstream side of the turbine. The compressor
14 and the turbine 20 are even connected together via a shaft 13.

Further, a bypass passage 22 is provided in the exhaust passage 8 so as to bypass the turbine installation position, and a waste gate valve 24 is provided in the passage 22. The wastegate valve 24 is connected to a diaphragm 30 of a wastegate actuator 28 via a rod 26. The wastegate actuator 28 has an atmosphere chamber 32 and a pressure chamber 34 which are partitioned by a diaphragm 30.
A spring 36 for urging the wastegate valve 24 in the closing direction is housed in 32. In this embodiment, the waste gate valve 24 and the waste gate actuator are used.
28 constitutes the supercharging pressure control means.

The pressure chamber 34 communicates with the intake passage 4 on the downstream side of the intercooler 16 via a passage 38, and the passage 38 communicates with the intake passage 4 on the upstream side of the compressor 14 via a passage 40. A solenoid valve 42 is interposed in the passage 40, and the solenoid valve 42 opens and closes the passage 40 based on a command signal from an electronic control unit 44 centered on a microcomputer. The electronic control unit 44 receives at least the engine speed signal from the engine speed sensor 46, the vehicle speed signal from the vehicle speed sensor 48, and the knock signal from the knock sensor 50 as input signals for controlling the opening / closing of the solenoid valve 42. Also, signals from various other sensors necessary for fuel injection amount control and ignition timing control are input.

In this embodiment, the fuel type information of the fuel used by the engine,
An electronic control unit 44 that sets a set pressure as a predetermined set value according to the vehicle speed and the engine speed, and an electromagnetic valve 42 that is controlled to be opened and closed by the electronic control unit 44 to a predetermined set value. It constitutes a set pressure adjusting means.

The intake manifold 2 is provided with an injector (not shown) for each cylinder, and the injector is supplied with fuel at a constant pressure via a fuel pressure regulator (not shown). Then, this injector injects fuel into the intake manifold 2 according to the opening time thereof, based on a command from the electronic control unit 44.

Next, the control mode of the solenoid valve 42 performed by the electronic control unit 44 will be described with reference to the flowchart of FIG.

In FIG. 2, the electronic control unit 44 determines whether the fuel used is a high octane fuel or a low octane fuel based on the fuel type information obtained from the result of cumulative evaluation of the signal from the knock sensor 46. (Step S1).

In the present embodiment, step S1 of determining whether the fuel used is a high octane fuel or a low octane fuel based on this fuel type information constitutes the fuel type determining means.

In step 1, when it is determined that the fuel is a low octane fuel, the solenoid valve 42 is always stopped from being energized.
Sends a signal to close 42 (step S2), while step S1
When it is determined that the fuel is a high octane fuel, it is determined in step S3 whether or not the vehicle speed exceeds a set value (for example, 15 km / hour). The valve 42 is opened (step S4).
Further, when it is determined in step S3 that the vehicle speed does not exceed the set value, it is determined in step S5 whether the engine speed exceeds the set value (for example, 300 rpm),
When it exceeds, an energization signal is output to the solenoid valve 42 to open the solenoid valve 42 (step S4).

When the engine speed does not exceed the set value in step S5, a signal to stop energizing the solenoid valve 42 is issued to close the solenoid valve 42 (step S2).

By the way, when the solenoid valve 42 is closed, the intake pressure on the downstream side of the intercooler 16 directly acts on the pressure chamber 34 of the wastegate actuator 28 through the passage 38, so that when the intake pressure reaches the first set positive pressure, The urging force in the pressure chamber 34 exceeds the urging force of the spring 36, and as a result, the waste gate valve 24 is opened and the intake pressure is suppressed from rising above the first set positive pressure.

On the other hand, when the solenoid valve 42 is opened, the pressure acting on the pressure chamber 34 of the wastegate actuator 28 is increased by the intercooler 16
Since it is a combined pressure of the intake pressure on the downstream side of the air cleaner and the pressure (approximately atmospheric pressure) from the passage 40 connected to the downstream side of the air cleaner 10, the intake pressure on the downstream side of the intercooler 16 is compressed to a certain degree. It will act on chamber 34. Therefore, when the solenoid valve 42 is opened, the wastegate valve 24 is opened only when the intake pressure on the downstream side of the intercooler 16 becomes the second set positive pressure larger than the first set positive pressure, that is, At this time, the intake pressure is prevented from rising above the second set positive pressure.

Therefore, when the solenoid valve 42 is closed, the intake pressure on the downstream side of the intercooler 16, that is, the maximum boost pressure is limited to the first set positive pressure, and when the solenoid valve 42 is opened, the maximum boost pressure is reduced to the first value. 1
Is increased to a second set positive pressure that is larger than the set positive pressure of.

In the above configuration, when a high-octane fuel is used, the boost pressure is kept relatively low at the start of acceleration, and thereafter, when the vehicle speed or engine speed exceeds the set value, the boost pressure becomes high. Supply pressure can be obtained. On the other hand, when a low octane fuel is used, the supercharging pressure can always be suppressed to a low value.

Therefore, especially when a high octane fuel is used, a rapid increase in engine torque is suppressed during start acceleration, a shock is prevented from starting, and a low octane fuel is used when the vehicle speed increases to a certain extent. Compared with the case, a high boost pressure setting value is obtained to obtain a high boost pressure.As a result, a high torque can be obtained by increasing the fuel supply amount from the injector to cope with the high boost pressure. The effect is that a strong acceleration state can be obtained.

At that time, because the low supercharging state can be released not only by the vehicle speed but also by the engine speed, the vehicle speed can be set to the set vehicle speed due to the slip of the fluid coupling, especially in a vehicle having an automatic transmission with a turbo type fluid coupling. Before reaching the target speed, if the rotational speed is already high enough to exceed the set rotational speed, that is, if the above-mentioned shock when starting is unlikely to occur, increase the boost pressure setting value to improve acceleration performance. Can
Further, even when a relatively inexpensive vehicle speed sensor is used, there is an effect that the operating state in which torque control is to be performed can be reliably grasped.

Further, when a low octane fuel is used, the supercharging pressure is always suppressed to a low value, so that knocking is suppressed and smooth operating characteristics are obtained.

In the above-mentioned embodiment, the operating state in which the maximum supercharging pressure should be reduced is detected by the vehicle speed and the engine speed, but in the case of detecting the operating state in which the maximum supercharging pressure is reduced as a countermeasure against shock at the time of starting acceleration, The torque may be reduced when the vehicle speed is low by detecting only the vehicle speed.

Further, in the above embodiment, the maximum boost pressure is controlled by the vehicle speed and the engine speed in consideration of the shock countermeasure at the time of starting acceleration. However, as shown in FIG. 3, for example, the maximum boost pressure is controlled according to the vehicle speed and the engine speed. The operating state is divided into smaller parts (6 in FIG. 3), and the optimum maximum boost pressure is obtained for each divided zone in consideration of the running state of the vehicle and the operating state of the engine. You may comprise. At that time, when controlling the maximum boost pressure in three or more stages more finely than in two stages of high and low, the solenoid valve
Not only the 42 is simply turned on or off, duty control (control of repeating on / off in a short time and making the on / off ratio at that time a predetermined value) may be performed.

Further, in the above embodiment, the vehicle speed sensor 48 is provided to reduce the maximum supercharging pressure at low vehicle speeds.However, instead of the vehicle speed sensor 48, the gear shift position sensor 52 for detecting the gear position of the transmission is provided, and the low speed The control may be performed so that the maximum supercharging pressure is always reduced when a low gear (for example, a low gear) used in the vehicle speed state is detected. When the shift position sensor 52 is used, the vehicle speed is estimated from the shift speed signal and the engine rotation speed signal from the engine rotation speed sensor 46, and the maximum boost pressure at low vehicle speed is calculated based on the estimated vehicle speed. May be configured to be reduced.

〔The invention's effect〕

According to the present invention, the boost pressure according to the fuel type information of the fuel used by the engine and the operating state of the vehicle, in particular, the speed of the vehicle or the gear position of the transmission of the vehicle that indirectly indicates the speed state of the vehicle. The maximum value of is adjusted, and when high octane fuel is used, the supercharging pressure is kept low during start-up acceleration at low vehicle speeds below the set vehicle speed or low gear steps below the set gear, and after this, A high boost pressure is obtained when the vehicle speed exceeds the set vehicle speed or the shift speed exceeds the set shift speed. On the other hand, when a low octane fuel is used, the supercharging pressure can always be suppressed to a low value.

Therefore, when using high-octane fuel,
A sudden increase in engine torque is suppressed during low start acceleration at a low vehicle speed below the set vehicle speed or at a low shift step below the set gear and a shock at start is prevented, and the vehicle speed exceeds the set vehicle speed. When the shift speed exceeds the set shift speed, higher boost pressure can be obtained by setting the boost pressure higher than that when low octane fuel is used. By increasing the fuel supply amount from the injector, high torque can be obtained, and a strong acceleration state can be obtained.

In addition, as in the case of a vehicle having an automatic transmission with a fluid coupling, before the vehicle speed reaches the set vehicle speed due to the slip of the fluid coupling, the rotation speed is already sufficiently high and exceeds the set rotation speed, that is, when the vehicle starts at In a state in which shock is unlikely to occur, the boost pressure set value is increased, and the acceleration performance is improved.

[Brief description of drawings]

FIG. 1 is a system diagram of an engine E according to an embodiment of the present invention, FIG. 2 is a flowchart showing an opening / closing operation mode of a solenoid valve 42 in the same embodiment, and FIG. 3 is another embodiment of the present invention. It is a graph which shows the control aspect of an example. E …… Engine 4 …… Intake passage 8 …… Exhaust passage 12 …… Turbocharger 14 …… Compressor 20 …… Turbine 24 …… Wastegate valve 28 …… Wastegate actuator 42 …… Solenoid valve 44 …… Electronic control unit 46 …… Engine speed sensor 48 …… Vehicle speed sensor 52 …… Shift position sensor

Claims (4)

(57) [Claims] 1. A combustion chamber of an engine, comprising: an engine mounted on a vehicle; a compressor installed in an intake passage of the engine; and a turbine installed in an exhaust passage of the engine to drive the compressor. An exhaust turbocharger for pressurizing the supplied intake air, a supercharging pressure control means for detecting the intake pressure of the compressor downstream side intake passage and controlling the operation of the exhaust turbocharger so that the intake pressure becomes equal to or less than a set pressure, Fuel type determination means for determining whether or not the used fuel is a high octane fuel based on the fuel type information of the fuel used for the engine, speed detection means for detecting the speed of the vehicle, and engine speed of the engine is detected. Rotational speed detection means, automatic transmission with a fluid coupling that is interposed in the drive system of the vehicle and transmits the output of the engine, fuel type determination means When the fuel used is determined to be other than the high octane fuel, the set pressure is set to the first set value, and when the fuel used is determined to be the high octane fuel, the set pressure is set to the first set value. A set pressure adjusting means for setting a second set value having a higher pressure than the above, and the set pressure adjusting means determines that the fuel used by the engine is a high octane fuel, and detects the speed detecting means. The set pressure is set to the first set value and is detected by the speed detecting means when the speed of the vehicle is equal to or lower than the set vehicle speed and lower than the set speed detected by the rotating speed detecting means. And setting the set pressure to the second set value when the speed of the vehicle is equal to or lower than the set vehicle speed and exceeds the set rotation speed detected by the rotation speed detection means. Intake pressure control device for the vehicle exhaust turbocharged engine, characterized 2. The set pressure adjusting means determines that the fuel used is a high octane fuel and the speed of the vehicle detected by the speed detecting means exceeds a set vehicle speed, and The set pressure is variably set to a plurality of set values having a pressure higher than the first set value according to the engine speed of the engine detected by the engine speed detecting means. Supercharging pressure control device for engine with exhaust turbocharger for vehicle described 3. An engine mounted on a vehicle, a compressor installed in an intake passage of the engine, and a turbine installed in an exhaust passage of the engine to drive the compressor, and a combustion chamber of the engine. An exhaust turbocharger for pressurizing the supplied intake air, a supercharging pressure control means for detecting the intake pressure of the compressor downstream side intake passage and controlling the operation of the exhaust turbocharger so that the intake pressure becomes equal to or less than a set pressure, Fuel type determination means for determining whether or not the used fuel is a high octane fuel based on the fuel type information of the fuel used for the engine, a shift speed detection means for detecting the shift speed of the transmission of the vehicle, the engine of the engine Rotation speed detecting means for detecting the rotation speed, automatic transmission with a fluid coupling interposed in the drive system of the vehicle and transmitting the output of the engine, the fuel When it is determined that the used fuel is other than the high octane number fuel by the different determination means, the set pressure is set to the first set value, and when it is determined that the used fuel is the high octane number fuel, the set pressure is set to the first set value. A set pressure adjusting means for setting a second set value having a pressure higher than the set value of 1 is provided, and further, the set pressure adjusting means determines that the fuel used by the engine is a high octane fuel, The set pressure is set to the first set value when the shift stage of the transmission of the vehicle detected by the shift detecting unit is equal to or lower than the set shift stage and is lower than the set rotation number detected by the rotation number detecting unit. In addition, when the shift speed of the transmission of the vehicle detected by the shift speed detecting means is less than or equal to the set shift speed and exceeds the set rotational speed detected by the rotational speed detecting means, the above setting is performed. Intake pressure control device for the vehicle exhaust turbocharged engine and sets the pressure to the second set value 4. The set pressure adjusting means determines that the fuel to be used is a high octane fuel, and the shift stage of the transmission of the vehicle detected by the shift stage detecting means exceeds the set shift stage. And variably setting the set pressure to a plurality of set values higher than the first set value in accordance with the shift speed of the vehicle and the engine speed of the engine detected by the speed detection means. The supercharging pressure control device for an engine with an exhaust gas turbocharger for a vehicle according to claim 3,