JPH11311123A - Supercharging and energy recovery device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently recover exhaust energy in time of non-supercharging as maintaining a supercharging characteristic excellent in responsiveness and good fuel consumption. SOLUTION: A turbine 17 is interposingly installed in an exhaust passage 18, and a compressor 16 being driven by rotation of this turbine 17 is interposingly installed in an air intake passage 11. Then a dynamoelectric machine 21 is attached to a rotary shaft connecting the turbine 17 and the compressor 16 to each other, and an electromagnetic clutch 22 is interposingly installed at least in a space between the dynamoelectric machine 21 and the compressor 16. According to the operating conditions, a controller 24 controls on-off operations of the electromagnetic clutch 22 and the dynamoelectric machine 21 so as to function as a motor or a generator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine provided with a supercharging and energy recovery device with a rotating electric machine.

[0002]

2. Description of the Related Art Conventionally, as an internal combustion engine provided with a supercharger having a rotating electric machine, there is one disclosed in Japanese Patent Application Laid-Open No. 6-50163.

[0003] In this method, a rotating electric machine is mounted on a rotating shaft of a turbocharger for supercharging an engine, and a current from an AC generator driven by the engine is supplied to the rotating electric machine when the engine is accelerating or the like. The turbocharger is driven to rotate the turbocharger, and boost-up during acceleration is performed with good response.

[0004]

However, in such an internal combustion engine having a supercharger with a rotating electric machine, the rotating electric machine is driven when a high output is required, such as when accelerating or traveling uphill. Although the response of the turbocharger can be improved by this, during normal operation without supercharging (during natural intake), the exhaust energy cannot be used effectively.
Alternatively, there is a problem that the compressor becomes an intake resistance.

The present invention has been proposed to solve such a problem. An internal combustion engine capable of efficiently recovering exhaust energy during non-supercharging while maintaining supercharging characteristics with good responsiveness. Provide an institution.

[0006]

According to a first aspect of the present invention, there is provided an internal combustion engine in which a turbine is provided in an exhaust passage and a compressor driven by rotation of the turbine is provided in an intake passage. A rotating electric machine is mounted on the rotating shaft, a clutch is interposed at least between the rotating electric machine and the compressor, and control means is provided for controlling the clutch and the rotating electric machine according to operating conditions.

In a second aspect based on the first aspect, clutches are interposed between the rotary electric machine and the compressor and between the rotary electric machine and the turbine, respectively.

According to a third aspect of the present invention, in the first or second aspect, the compressor is interposed in a passage bypassing the intake passage, and a switching valve for selectively flowing intake air to the bypass passage or the intake passage is provided. The switching valve is switched by the control means according to the operating conditions.

In a fourth aspect based on the third aspect, an electric control throttle is interposed upstream of the switching valve, and the opening degree of the electric control throttle is controlled by the control means in accordance with operating conditions. did.

In a fifth aspect based on the first or second aspect, the control means disconnects a clutch between the compressor and the rotating electric machine in a non-supercharging region, and causes the rotating electric machine to generate electricity as a generator.

In a sixth aspect based on the first, second or fifth aspect, the control means connects a clutch between the compressor and the rotating electric machine in a supercharging region, and sets the rotating electric machine in an operating state. It functions as a motor or a generator as appropriate.

[0012]

According to the first aspect of the present invention, the clutch is turned on / off according to operating conditions, and the rotating electric machine is caused to function as a motor or a generator. To generate electricity using exhaust energy,
Alternatively, in the operation area where supercharging is required, the compressor is driven by the turbine and motor, and supercharging is performed responsively from the low rotation speed range, or a part of the exhaust energy is absorbed by the generator, preventing the engine from overspeeding, Or in the fuel economy range. As a result, it is possible to recover exhaust energy during non-supercharging and to improve responsiveness and fuel economy characteristics during supercharging.

In the second invention, clutches are interposed on both sides of the rotating electric machine, respectively, and these two clutches are connected and disconnected according to operating conditions, so that exhaust energy can be recovered finely and fuel efficiency can be improved.

According to the third aspect of the present invention, the intake valve can be reduced when supercharging is unnecessary by guiding or bypassing the flow of intake air to the compressor by the switching valve.

In the fourth invention, by controlling the opening of the electric control throttle together with the control of the clutch and the rotating electric machine,
It is possible to increase the intake air temperature and the exhaust gas temperature during a cold operation or the like to promote warm-up, or to increase the power consumption by the rotating electric machine when the battery is overcharged, thereby alleviating the overcharge.

According to the fifth aspect of the present invention, the clutch is disengaged in the non-supercharging region, the generator is generated by the exhaust energy, and the compressor is free to reduce the intake loss.

In the sixth aspect of the invention, the clutch is connected in the supercharging region, and the rotating electric machine functions as a motor or a generator according to the operation state, thereby improving acceleration characteristics and increasing the engine speed to the best fuel consumption range. Can be maintained.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

In this embodiment, the present invention is applied to a hybrid vehicle. In FIG. 1, reference numeral 1 denotes an engine which outputs by combustion of fuel, and a generator / motor is provided on an output shaft 2 of the engine 1 via an electromagnetic clutch 3. 4 are linked,
A continuously variable transmission (CV) is provided on the output side of the generator motor 4.
T) 5 is connected, and the output rotation of the continuously variable transmission 5 is transmitted to the left and right drive wheels 6, 6 via the axle.

In a low-speed and low-load range including when the vehicle starts, the engine 1 is stopped, the electromagnetic clutch 3 is disconnected, and the generator / motor 4 receives power supplied from a battery (not shown) and functions as a motor. Then, the drive wheels 6 are rotated via the continuously variable transmission 5. When the load becomes large, such as during acceleration of the vehicle, the engine 1 is started, the electromagnetic clutch 3 is engaged, and the vehicle is driven by the engine output and the motor output. On the other hand, when the vehicle decelerates or when the battery voltage decreases, the generator / motor 4 is driven to rotate by the inertial energy of the vehicle or the engine output, generates power as a generator, and charges the battery. These controls are performed by a controller 24 described later.

An intake passage 11 of the engine 1 is provided with a throttle 12 which is electrically controlled, and a downstream passage 14 selectively connected via a switching valve 13 downstream thereof.
Branches. In this bypass passage 14, the turbocharger 1
The compressor 16 of the supercharger constituted by 5 is interposed,
Supercharge the intake air when the engine is accelerating. A turbine 17 of the turbocharger 15 is interposed in an exhaust passage 18 of the engine 1, and the turbine 17 is rotated by exhaust energy. The turbine 17 is connected to the compressor 16 via a rotating shaft 20, and a rotating electric machine 21, which also functions as a generator and a motor, is mounted on the way, and the rotating electric machine 21 rotates in the same way by the rotation of the turbine 17. An electromagnetic clutch 22 is interposed between the rotating electric machine 21 and the compressor 16. When the electromagnetic clutch 22 is shut off (turned off), the compressor 16 is separated from the turbine 17. Note that a catalyst 23 is provided in the exhaust passage 18 downstream of the turbocharger 15.

The supercharger supercharges the intake air by utilizing the exhaust energy when the required output of the vehicle is large, and drives the compressor 16 by the rotating electric machine 21 as necessary, or does not require supercharging. At this time, the electromagnetic clutch 22 is disconnected and the rotating electric machine 21 is driven by the turbine 17 to generate electric power.

For this reason, the throttle 12 and the switching valve 1
3. A controller (control means) 24 for controlling each operation of the electromagnetic clutch 22 and the rotating electric machine 21 according to the operating conditions.
Is provided. The controller 24 includes an accelerator sensor (engine load sensor) for detecting the accelerator pedal opening, a rotation speed sensor for detecting the engine speed, a throttle sensor for detecting the throttle opening, and a temperature for detecting the engine lubricating oil temperature or the coolant temperature. Detection signals representing operating conditions such as sensors, a battery sensor for detecting a battery charge level, a negative pressure sensor for detecting a negative pressure in an intake system, a pressure sensor for detecting a pressure upstream and downstream of a turbine in an exhaust system, and the like. , And based on these signals, as described later, the throttle 12 and the switching valve 1
3. Control the operations of the electromagnetic clutch 22 and the rotating electric machine 21.

The controller 24 also controls the fuel injection amount and the ignition timing of the engine 1 at the same time.

The control executed by the controller 24 is shown in the flowchart of FIG.

First, in step S1, the elapsed time after starting the engine is integrated. In step S2, signals representative of various operating conditions include engine load, rotation speed, throttle opening, oil temperature or cooling water temperature, battery charge level. And so on.

In step S3, based on the signals representative of these operating conditions, it is roughly divided into a non-supercharging time and a supercharging time, and in each of the operating conditions shown in FIG. The corresponding condition is selected (however, the operating condition of the clutch indicates the type described in the figure as type A).

In step S4, control contents are selected in accordance with these operating conditions. The details of these controls will be described in detail below. Then, in step S5, it is determined whether the engine 1 is on or off. When the running of the vehicle is on with the operation of the engine 1, the above-mentioned routine is repeatedly executed, and when the engine 1 is off, this control is stopped.

The control content shown in FIG. 3 is based on the assumption that a supercharged region or a non-supercharged region is selected from the operation region shown in FIG. 4 based on the engine load and the number of revolutions. The zone is a non-supercharged region, and the B zone having a larger load is a supercharged region.

First, the non-supercharged area (A zone) will be described.

During normal operation other than during idling or cold, that is, the accelerator pedal is depressed to turn on, the water temperature is equal to or higher than a predetermined value T0, and the battery level is equal to the allowable maximum voltage V
When it is 0 or less, as shown in FIG.
3 opens the intake passage 11 (closes the bypass passage 14), turns off the electromagnetic clutch 22, and causes the rotating electric machine 21 to function as a generator. Also, as shown in FIG. 8, the throttle opening is determined according to the opening of the accelerator pedal and the like, and the engine speed is controlled.

In this state, the intake air in the intake passage 11 does not pass through the bypass passage 14, and the compressor 16 does not have intake resistance during the natural intake operation.

The turbine 17 of the turbocharger 15
As a result, only the rotating electric machine 21 is driven, and this generates electric power as a generator, thereby charging the battery and recovering the exhaust energy efficiently.

Idle Operation Condition with Accelerator Pedal Fully Closed Under this idle condition, the difference is that the rotating electric machine 21 functions as a motor. , The downstream pressure is increased. As a result, the internal exhaust gas recirculation rate, which depends on the pressure difference between the intake pressure and the exhaust pressure (turbine upstream pressure), is reduced, and the combustion during idling is stabilized.

During cold operation, the engine cooling water temperature or oil temperature is low (for example, when the water temperature is 40
At the time of the cold operation (° C. or less), the cases of a and b can be selected. In the case of a, the switching valve 13 is closed to open the bypass passage 14, the electromagnetic clutch 22 is turned on, and the rotating electric machine 21 is used as a motor. The compressor 16 is driven to rotate. At this time, as shown in FIG. 9, the opening degree of the throttle 12 is narrowed down as compared with the normal operation in the non-supercharged state after the warm-up. As a result, the intake air is supercharged in a state where the intake air is narrowed, so that the intake air temperature rises and the warm-up of the engine 1 can be promoted. Since the throttle 12 is throttled down even when the engine is supercharged, the engine intake air amount does not increase more than necessary.

On the other hand, in the case of b, the switching valve 12 is opened, the electromagnetic clutch 22 is turned off, the rotating electric machine 21 functions as a motor, and the exhaust pressure downstream of the turbine is increased, as in the idle condition described above. The exhaust gas temperature is increased, and the activation of the catalyst 23 downstream thereof is promoted.

When the battery is overcharged, the cases a and b can be selected even when the battery is overcharged when the battery charge level is higher than the specified value. In the case of a, the switching valve 13, the electromagnetic clutch 22, and the rotary electric machine 21 All are controlled in the same manner as in the case of a. FIG.
As shown by 0, the throttle opening is also narrowed down more than usual. For this reason, the work of the rotating electric machine 21 as a motor for rotating the compressor 16 increases, the power consumption of the battery increases, and the state of overcharge is eased.

On the other hand, in the case of b, the control is performed in exactly the same manner as in the idle condition except for the throttle opening. Therefore, the turbine 17 is rotationally driven by using the rotating electric machine 21 as a motor, battery current is consumed, and overcharging is eased. In this case, the compressor 16
Becomes free and does not affect the intake air amount and the like, so that the control of the intake air amount through the throttle 12 becomes simple.

Next, a description will be given of a supercharging region in which the operating region is the zone B in FIG.

During normal operation During normal operation when the accelerator is on and the cooling water temperature is sufficiently high,
The switching valve 13 is switched as shown in FIG.
Then, the intake air is supplied to the compressor 4, the electromagnetic clutch 22 is connected, the compressor 16 is driven to rotate, and the throttle 12 is fully opened to perform supercharging.

In this case, even when the throttle is fully opened, the amount of intake air can be controlled by the rotation of the compressor 16, and the rotating electric machine 21 is used as a motor in accordance with the conditions so that the engine operation at that time becomes the best fuel efficiency with respect to the required output. Compressor 1
6 is controlled.

The engine speed at which the fuel efficiency is the best for each of the equal output characteristic lines of the engine is specified. When it is desired to reduce the required speed of the compressor 16, that is, the rotating electric machine 21, to maintain a certain engine speed. Use a generator and a motor if you want to raise it. Therefore,
By controlling the rotating electrical machine 21 to be a generator or a motor in accordance with the required output characteristics during supercharging, the rotation of the compressor 16 can be freely controlled, and the engine speed can be controlled as required.

When the rotating electric machine 21 is a generator, as shown in FIG. 7, the lower the rotation speed, the higher the exhaust pressure upstream of the turbine 17 than the downstream exhaust pressure, and the lower the rotation speed. The lower the pressure, the greater the differential pressure, and when functioning as a motor, the exhaust pressure reverses, and the higher the number of revolutions, the higher the pressure on the downstream side.

When the rotating electric machine 21 is functioning as a generator, the electric power is generated by the excess energy of the exhaust gas.
When the energy is recovered and the compressor 16 is rotated by switching to the motor, the necessary amount of supercharging can be performed even when the exhaust pressure is not sufficient, and good output characteristics can be exhibited.

At the time of cold operation Next, at the time of cold operation in which the cooling water temperature and the like are low, the rotating electric machine 21 is always kept a motor under the conditions of normal operation. Then, the opening degree of the throttle 12 is reduced, whereby the work amount of the compressor 16 for the same intake air amount is increased, the intake air temperature is increased, and the warm-up of the engine is promoted.

Battery Overcharge At the time of overcharge of the battery, the turbocharger 15 is driven by using the rotating electric machine 21 as a motor, and the power of the battery is consumed by the same as at the time of overcharge without non-supercharging.
In addition, since the driving force of the motor is added in addition to the rotation of the turbine 17, the supercharging response of the turbocharger 15 is improved.

As described above, according to the present invention, the electromagnetic clutch 22 interposed between the compressor 16 of the turbocharger 15 and the rotary electric machine 21 is connected and disconnected according to the operating conditions, and the rotary electric machine 21 functions as a motor or a generator. By doing so, during non-supercharging, it is possible to recover the exhaust energy of the engine as a normal intake engine, and to improve fuel efficiency and output responsiveness during supercharging.

Further, when applied to a hybrid vehicle as in this embodiment, efficient supercharging is performed when a high output operation is required, so that the size of the engine can be reduced, and exhaust energy recovery during non-supercharging can be achieved. Thereby, fuel economy can be promoted.

However, it goes without saying that the present invention is not limited to a hybrid vehicle, but can be applied to a vehicle driven only by a normal internal combustion engine.

Next, a second embodiment will be described with reference to FIG.

This is the turbine 1 of the turbocharger 15.
A second electromagnetic clutch 35 is provided between the rotary electric machine 7 and the rotating electric machine 21, and by controlling the first and second electromagnetic clutches 22 and 25, fuel efficiency and energy recovery efficiency can be further improved. is there.

The first and second electromagnetic clutches 22 and 25
3 is as described in FIG. 3, but the switching valve 13, the rotating electric machine 21, and the first electromagnetic clutch 22 are controlled in principle in the same manner as in the first embodiment (see FIG. 3). However, in FIG. 3, it is illustrated as type B, and the clutch a is the first electromagnetic clutch, the clutch b
Means the second electromagnetic clutch).

First, during the normal operation, the second electromagnetic clutch 25 is turned on, so that the rotating electric machine 21 is driven by the turbine 17 as a generator, and energy is recovered by power generation without supercharging. By turning on or off the second electromagnetic clutch 25 at the time of idling, the turbine 17 is driven by the motor or the turbine 17 is made free. By driving the turbine 17, the internal exhaust gas recirculation rate is reduced, and the exhaust gas resistance is reduced by setting it free.

During the cold operation, the second electromagnetic clutch 25 is turned off in both cases a and b. In this case, when the first electromagnetic clutch 22 is ON, the compressor 16 is rotated by the motor to compress the intake air to increase the intake air temperature, promote warm-up, and
When 2 is off, both the compressor 16 and the turbine 17 are free, reducing exhaust loss and promoting warm-up.

When the battery is overcharged, the second electromagnetic clutch 25 is controlled to be turned on or off. When the second electromagnetic clutch 25 is on, the turbocharger 15 is driven by the motor, and the turbocharger is supercharged while the throttle is being throttled, so that the work of the rotary electric machine 21 is increased and overcharging is reduced. At this time, when the turbine 17 is disconnected by turning off the second electromagnetic clutch 25, the driving load of the rotating electric machine 21 further increases, and the power consumption can be increased. When the first electromagnetic clutch 22 is off, the compressor 16 and the turbine 17 are both free, and the electric power is simply consumed by the rotating electric machine 21 without affecting the performance of the engine, so that overcharging can be mitigated.

Next, the supercharging operation will be described. During the normal operation, the second electromagnetic clutch 25 is turned on. In this state, exactly the same as in the first embodiment, the rotating electric machine 21 is made to function as a motor or as a generator depending on the conditions so that the engine operation becomes the best fuel efficiency with respect to the required output. Control rotation. Also, during the cold operation, the second electromagnetic clutch 25 is on, and the rotating electric machine 21 is always kept as a motor. As a result, the intake air is compressed to increase the intake air temperature, thereby promoting warm-up of the engine.

When the battery is overcharged, the second electromagnetic clutch 25 is turned on or off. Second electromagnetic clutch 35
When is turned on, the operation is the same as that of the first embodiment. When it is turned off, the compressor 16 is driven only by the motor, so that the power consumption of the rotating electric machine 21 increases accordingly, and overcharging can be eased. .

By thus interposing the second electromagnetic clutch 25 between the rotating electric machine 21 and the turbine 17,
By controlling these together with the first electromagnetic clutch 22 more finely in accordance with the operating conditions, it is possible to achieve more excellent regeneration of exhaust energy and improvement of fuel efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing the control operation.

FIG. 3 is an explanatory diagram showing an operation state of each unit including a clutch and a rotating electric machine.

FIG. 4 is an explanatory diagram showing a supercharging region and a non-supercharging region.

FIG. 5 is a schematic configuration diagram showing a state in which a switching valve closes a bypass passage.

FIG. 6 is a schematic configuration diagram showing a state in which a switching valve opens a bypass passage.

FIG. 7 is an explanatory diagram showing a relationship between a function of the rotating electric machine and a differential pressure between a turbine inlet and an outlet.

FIG. 8 is an explanatory diagram showing characteristics of a throttle opening during non-supercharging idling.

FIG. 9 is an explanatory diagram showing characteristics of a throttle opening at the time of non-supercharging cold.

FIG. 10 is an explanatory diagram showing characteristics of a throttle opening during non-supercharging and overcharging.

FIG. 11 is a schematic configuration diagram of a turbocharger showing another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 engine 3 electromagnetic clutch 4 motor generator 5 continuously variable transmission 11 intake passage 12 electrically controlled throttle 13 switching valve 15 turbocharger 16 compressor 17 turbine 18 exhaust passage 21 rotating electric machine 22 electromagnetic clutch 24 controller 25 electromagnetic clutch

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02B 61/00 F02B 61/00 E F02D 29/06 F02D 29/06 L F02N 11/04 F02N 11/04 Z

Claims (6)

[Claims] In an internal combustion engine in which a turbine is interposed in an exhaust passage and a compressor driven by rotation of the turbine is interposed in an intake passage, a rotating electric machine is mounted on a rotating shaft connecting the turbine and the compressor, and at least A supercharging and energy recovery apparatus for an internal combustion engine, comprising: a clutch interposed between a rotating electric machine and a compressor; and control means for controlling the clutch and the rotating electric machine according to operating conditions. 2. The supercharging and energy recovery system for an internal combustion engine according to claim 1, wherein clutches are interposed between the rotating electric machine and the compressor, and between the rotating electric machine and the turbine, respectively. 3. A switching valve for selectively introducing air to the bypass passage or the intake passage, wherein the switching valve is provided by the control means in accordance with an operating condition. 3. The supercharging and energy recovery device for an internal combustion engine according to claim 1, wherein the device is switched. 4. An internal combustion engine according to claim 3, wherein an electric control throttle is interposed upstream of said switching valve, and the opening degree of said electric control throttle is controlled by said control means according to operating conditions. Supercharging and energy recovery device. 5. The supercharging and energy of an internal combustion engine according to claim 1, wherein the control means disconnects a clutch between the compressor and the rotating electric machine in a non-supercharging region and generates electric power using the rotating electric machine as a generator. Collection device. 6. A control system according to claim 1, wherein said control means connects a clutch between said compressor and said rotating electric machine in a supercharging region, and causes said rotating electric machine to function as a motor or a generator according to an operation state. A supercharging and energy recovery device for an internal combustion engine according to claim 1.