JPH06323149A - Engine with exhaust driven superconductor - Google Patents

Abstract

PURPOSE:To reduce a rise up delay of an engine output due to a turbo lag by providing a decision means for judging an exhaust driven supercharger for whether in an operating condition or not of generating the turbo lag and a control means for controlling an intake bypass valve. CONSTITUTION:An intake bypass passage 30 for connecting a part 11 to the atmosphere is provided in a side of an engine 10 from a compressor 21 in an intake passage 11. An intake bypass valve 31 is provided in this intake bypass passage 30. In a decision means 3, based on a signal of at least one sensor 2 of showing an operation condition of the engine 10, a discharge driven supercharger 20 is judged for whether it is in an operation condition or not of generating a turbo lag. In a control means 1, when the decision means 3 decides the supercharger 20 placed in the operation condition of generating the turbo lag, the intake bypass valve 31 is opened through an actuator 32, and also when elapsed a prescribed time from this decision, the intake bypass valve is again closed. In this way, a rise up delay of an engine output due to the turbo lag can be decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine with an exhaust drive supercharger in which a compressor provided in an intake passage is driven by a turbine provided in an exhaust passage.

[0002]

2. Description of the Related Art In an engine with an exhaust gas driven supercharger of this type, a turbo lag (a time delay from the start of acceleration until the supercharger substantially starts operating) when the vehicle is rapidly accelerated from a low load and low rotation state. ) Occurs, which delays the rise of the engine output. This is because even if the exhaust energy increases, the increase of the compressor load due to the increase of the supercharging pressure and the inertial mass of the impeller system delays the rotation increase of the compressor. This problem has been solved by reducing the weight of the impeller system and using twin turbos.

[0003]

However, there is a problem that the above-mentioned conventional solutions are expensive.
An object of the present invention is to solve such a problem by reducing the load on the compressor when the operating condition that causes the turbo lag is reached.

[0004]

To this end, an engine with an exhaust gas driven supercharger according to the present invention has a compressor 21 and a turbine 22 of an exhaust gas driven supercharger 20 as shown in FIG.
In an engine with an exhaust drive supercharger provided in the intake passage 11 and the exhaust passage 12 of the engine 10, respectively,
1 shows an intake bypass passage 30 that connects a portion 11b of the intake passage 11 on the engine 10 side of the compressor 21 to the atmosphere side, an intake bypass valve 31 provided in the intake bypass passage 30, and an operating state of the engine 10. Determination means 3 for determining whether or not the exhaust driven supercharger 20 is in an operating condition causing a turbo lag based on a signal from at least one sensor 2, and an operating device 32 for opening and closing the intake bypass valve 31. When the determination means 3 determines that the operating condition that causes the turbo lag, the intake bypass valve 31 is opened via the actuating device 32, and the control means 1 that closes the intake bypass valve after a predetermined time has elapsed from the determination. It is characterized by having.

[0005]

The determining means 3 operates under the operating condition that a signal from the sensor 2 indicating the operating state of the engine 10 causes a turbo lag such as a low intake pipe pressure (supercharging pressure) and a large increase rate of the throttle opening. If it is determined that there is such an operating condition, the control means 1 determines that the operating device 32
The intake bypass valve 31 is opened via. As a result, the load on the compressor 21 is reduced, so that the exhaust gas driven supercharger 20
The rotation speed of increases rapidly. If a predetermined time has passed,
The control means 1 closes the intake bypass valve 31 to perform supercharging by the exhaust gas driven supercharger 20 whose rotation speed is increasing.

[0006]

As described above, according to the present invention, even when the turbo lag is generated, supercharging is performed by the exhaust drive supercharger whose rotational speed is rapidly increased. Decreases. Also,
What is needed for this is an intake bypass passage, an intake bypass valve and its operating device, which are very common parts,
The sensors, the control means, and the determination means may be the ones that a normal engine already has, and thus can be economically implemented.

[0007]

First, the first embodiment shown in FIG. 2 will be described. The engine 10 of an automobile or the like includes an exhaust gas driven supercharger 20 including a compressor 21 provided in the middle of the intake passage 11 and a turbine 22 provided in the middle of the exhaust passage 12. The impellers 21a, 22a of the compressor 21 and the turbine 22 are connected by a turbine shaft 23, and when the turbine impeller 22a is rotated by the exhaust energy from the engine 10, the compressor 21 is also rotationally driven to perform supercharging.

An air cleaner 14 is provided at the open end of the intake passage 11 on the upstream side of the compressor 21, and an air cleaner 14 is provided at a portion 11b located between the compressor 21 and the engine 10.
A throttle valve 13, a suction pressure sensor 42, and an air flow meter 43 are provided. Although illustration is omitted, in the present embodiment, the injection valve provided in the intake passage 11 located downstream of the throttle valve 13 injects gasoline in an amount corresponding to the intake air amount.

The exhaust passage 12 is provided with an exhaust bypass passage 28 connecting the upstream and downstream portions 12a and 12b of the turbine 22, and the exhaust bypass passage 28 has an opening to the downstream portion 12b. Waste gate valve 25
Is provided. A diaphragm-type actuator 26 that operates the wastegate valve 25 is communicated with the outlet side of the compressor 21 by a control passage 27, and when the boost pressure of the compressor 21 becomes a predetermined value or more, the wastegate valve 25 is opened and the turbine 22 of the turbine 22 is opened. The output is controlled to prevent the boost pressure from rising excessively.

The intake passage 11 is provided with an intake bypass passage 30 connecting the upstream and downstream parts 11a and 11b of the compressor 21, and an intake bypass valve 31 is provided in the middle thereof. In the present embodiment, the operating device 32 for operating the intake bypass valve 31 is a diaphragm type pneumatic actuator, and the intake bypass valve 31 is closed by the spring 32a in the inoperative state.
A sensing port 36 for taking out the intake pipe negative pressure is provided at a position downstream of the throttle valve 13 in the intake passage 11, and the negative pressure taken out from this is accumulated in the accumulator tank 34 via the check valve 35. The two ports of the three-way solenoid valve 37 controlled by the electronic control unit 40 described below are connected to the accumulator tank 34 and the pneumatic actuator 32, and the remaining one port is open to the atmosphere via the air filter 38.

An electronic control unit 40, which controls the entire engine 10 and controls the three-way solenoid valve 37, is connected to the throttle opening sensor 41, the intake pressure sensor 42 and the air flow meter 43. This electronic control unit 4
0 determines whether or not there is an operating condition that causes a turbo lag by arithmetically processing signals from these sensors that indicate the operating state of the engine 10, and determines by a built-in timer that a predetermined time has elapsed from this determination. However, if it is first determined that the operating condition that causes the turbo lag, it is determined that the intake bypass valve 3 is operated via the three-way solenoid valve 37 and the pneumatic actuator 32.
1 is opened, and if it is determined that a predetermined time t0 (for example, about 0.5 seconds, (the time required to reach the maximum turbine rotation speed) × 0.7 to 0.8) has elapsed, the intake bypass valve 31 is closed.

Whether the engine 10 is in a driving condition that causes a turbo lag is determined by, for example, an increase rate ΔD / Δt of the opening D of the throttle valve 13 detected by the throttle opening sensor 41 and an intake pressure sensor 42. Performed by the detected intake pipe pressure (supercharging pressure) P, when ΔD / Δt is larger than a predetermined value A (for example, 100 deg / sec) and P is lower than a predetermined value P0 (for example, +450 mmHg). It is determined that the operating conditions are such that turbo lag occurs. Alternatively, when the throttle opening D is near the minimum position and the rate of increase is large, it may be determined that the operating condition is such that turbo lag occurs.

In the comparison between the configuration described in the claims and the embodiment, the throttle opening sensor 41, the intake pressure sensor 42 and the air flow meter 43 correspond to the sensors, the pneumatic actuator 32 corresponds to the actuator, and the electronic control is performed. The device 40, the accumulator tank 34, the three-way solenoid valve 37, etc. correspond to the control means and the determination means.

Next, the operation of the above embodiment will be described with reference to the operation state diagram shown in FIG. 3 and the flow chart shown in FIG.
If the main switch of the engine is turned on, the electronic control unit 4
When 0 is set, each variable is set to a predetermined initial value to start the operation, and every time an interrupt signal is input at a predetermined short time interval, the operation according to the flowchart of FIG. 4 is repeatedly executed.

The electronic control unit 40 first reads the throttle opening D and the intake pipe pressure P from the throttle opening sensor 41 and the intake pressure sensor 42 in step 10, and the increase rate ΔD / Δt of the throttle opening is predetermined in step 11. It is determined whether the value is larger than the value A and the intake pipe pressure P is smaller than the predetermined value P0. Until time t1 in Fig. 3 (a), the throttle opening D is constant at a minimum value or a value D1 near it,
In this state, P <P0 but not ΔD / Δt> A, so the electronic control unit 40 advances the control operation from step 11 to step 17, and executes step 10 each time an interrupt signal is received.
Step 11, step 17, and step 18 are repeated. In this state, the pneumatic actuator 32 is communicated with the atmosphere through the air filter 38 by the three-way solenoid valve 37, and the intake bypass valve 31 remains closed by the spring 32a. Therefore, as shown by N1 and P1 in FIGS. 3B and 3C, the turbine rotation speed is low, the intake pipe pressure is low, and supercharging is not performed.

If the throttle opening is suddenly opened to a considerable opening D2 at time t1, ΔD / Δt> A and P <P0. Therefore, the electronic control unit 40 sets the operating condition for the engine 10 to generate a turbo lag. It is determined that there is, the control operation proceeds from step 11 to step 12, the timer which operates by the built-in clock is activated, and the time measured by the timer reaches step T0 until a predetermined time t0 is reached.
Repeat 15 During that time, the pneumatic actuator 32 is communicated with the accumulator tank 34 by the three-way solenoid valve 37, and the rod 31a is retracted against the spring 32a to open the intake bypass valve 31. As a result, the pressure difference before and after the compressor 21 disappears and the load on the compressor 21 decreases, so that the turbine rotation speed of the exhaust gas driven supercharger 20 rapidly increases as shown by the broken line N2 in FIG. 3 (b).

When the time t measured by the timer reaches the predetermined time t0, the electronic control unit 40 stops the timer in step 16 to stop the control operation. At this point in time, the transient increase in the throttle opening has ended, and during the operation by the next interrupt signal, step 10, step 11, step 17, and step 18 are repeated to make the intake bypass valve 3
Close 1 Due to this, supercharging is performed by the compressor impeller 21a whose rotational speed is increasing, and the intake pipe pressure increases as indicated by the broken line P2 in FIG. 3 (c). Due to the increase in the load on the compressor impeller 21a caused by the start of the supercharging, the turbine rotation speed rapidly increased and once decreased as shown by a broken line N2 in FIG. It becomes a value.

As described above, according to the present embodiment, the rotation speed of the exhaust gas driven supercharger 20 rapidly increases even under the operating condition that causes the turbo lag, and when the rotation speed increases, the intake bypass valve 31 is closed and supercharging is performed. As a result, the delay in the rise of the engine output due to the turbo lag is reduced. On the other hand, in the conventional technology that does not include the intake bypass passage 30 and the intake bypass valve 31, the load on the compressor wheel does not decrease under the operating conditions in which the engine 10 causes a turbo lag, so that the turbine rotation speed is reduced. The rise is delayed as shown by the solid line N3 in FIG. 3 (b), and the rise in intake pipe pressure is also delayed as shown by the solid line P3 in FIG. 3 (c), and the rise of the output due to the turbo lag is the same as in the first embodiment. It is delayed by the time T.

Next, the second embodiment shown in FIG. 5 will be described. In the second embodiment, the actuator 32 is composed of a servomotor, and the rod 31a is axially moved to open and close the intake bypass valve 31. Therefore, the three-way solenoid valve 37, the accumulator tank 34, etc. are unnecessary. Since the structure other than this is the same as that of the first embodiment, the same portions as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In the second embodiment, the electronic control unit 40 corresponds to the control means and the determination means.

The electronic control unit 40 normally operates the servo motor 32 so as to close the intake bypass valve 31. If it is determined that the engine 10 is in an operating condition that causes a turbo lag, the electronic control unit 40 actuates the servo motor 32 and retracts the rod 31a to cause the intake bypass valve 3 to move.
Open one. As a result, the load on the compressor 21 is reduced, so that the rotation speed of the exhaust gas driven supercharger 20 is rapidly increased. Then, after a lapse of a predetermined time, the electronic control unit 40 again operates the servo motor 32 in the opposite direction to close the intake bypass valve 31, and supercharging by the exhaust gas driven supercharger 20 whose rotation speed is increasing. Therefore, as in the first embodiment, there is no delay in the rise of the engine output due to the turbo lag.

In the first embodiment, the pressure acting on the pneumatic actuator 32 is selectively switched between the negative pressure and the atmospheric pressure of the accumulator tank 34 by the three-way solenoid valve 37.
The intake bypass valve 31 substantially only opens and closes. Therefore, when the intake bypass valve 31 is closed after a predetermined period of time, the output of the engine 10 may suddenly increase and a so-called acceleration shock may occur. However, according to the second embodiment in which the servomotor is used as the actuating device 32, the acceleration shock can be eliminated by gradually decreasing the opening degree of the intake bypass valve 31 to close it.

Although the above embodiments have been described with reference to the intake pipe injection type gasoline engine, the present invention is also applicable to a carburetor type gasoline engine provided with an exhaust gas driven supercharger or a diesel engine. In the case of a diesel engine, negative pressure may be accumulated in the accumulator tank 34 of the first embodiment by using a vacuum pump used for a vacuum servo brake or the like.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an engine with an exhaust gas driven supercharger according to the present invention.

FIG. 2 is an overall view of a first embodiment of an engine with an exhaust gas driven supercharger according to the present invention.

FIG. 3 is a diagram showing an operating state of the first embodiment shown in FIG.

FIG. 4 is a flowchart of the first embodiment shown in FIG.

FIG. 5 is an overall view of a second embodiment of the engine with an exhaust gas driven supercharger according to the present invention.

[Explanation of symbols]

2 ... Sensor, 10 ... Engine, 11 ... Intake passage, 11b
... part, 12 ... exhaust passage, 20 ... exhaust drive supercharger, 21
... compressor, 22 ... turbine, 30 ... intake bypass passage, 31 ... intake bypass valve, 32 ... operating device.

Claims (1)

[Claims] 1. In an engine with an exhaust gas driven supercharger in which a compressor and a turbine of an exhaust gas driven supercharger are respectively provided in an intake passage and an exhaust passage of an engine, a portion of the intake passage closer to the engine than the compressor is disposed. An operating condition in which the exhaust gas driven supercharger causes a turbo lag based on a signal from an intake bypass passage communicating with the atmosphere side, an intake bypass valve provided in the intake bypass passage, and at least one sensor indicating an operating state of the engine. Determining means for determining whether the intake bypass valve is open or closed, an operating device for opening and closing the intake bypass valve, and when the determining means determines that an operating condition that causes a turbo lag is met, the intake bypass valve is operated through the operating device. And a control means for closing the intake bypass valve when a predetermined time has elapsed from the determination Exhaust-driven turbocharged engine.