JP4082348B2 - Power generation system for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that includes a generator that generates power using suction negative pressure and a generator that generates power using shaft output of the engine.

  Conventionally, as a technique for increasing engine output, a positive displacement turbocharger driven by an engine or an electric motor provided in an engine intake passage, a so-called supercharger is known.

In Patent Document 1, a positive displacement turbocharger connected to an electric motor and a generator is used to perform supercharging by driving the positive displacement turbocharger with a motor at a high load, and an intake negative pressure of an engine at a low load. Discloses a technique for generating electric power using a generator connected to a positive displacement turbocharger that rotates by the above-described method.
JP 2002-357127 A

  However, since the system described in Patent Document 1 also functions as a supercharger, a relatively large positive displacement turbocharger is required. However, when generating electricity, the large positive displacement turbocharger is driven to generate power. Doing so is never good for power generation efficiency.

  When considered as a generator, it is preferable to rotate a relatively small generator at high speed in terms of power generation efficiency. In such a case, the ability to generate power with suction negative pressure and the required required power do not necessarily match. Therefore, in addition to the generator driven by the suction negative pressure, a method of providing a generator driven by the shaft output of the engine that is normally used can be considered. The issue is whether to use them properly.

  Therefore, an object of the present invention is to control a power generation system including a generator driven by suction negative pressure and a generator driven by engine shaft output so as to satisfy required power requirements efficiently. And

A power generation system for an internal combustion engine according to the present invention includes a rotor interposed in an intake passage of the internal combustion engine, a first generator that is connected to the rotor and generates power when the rotor rotates, and a shaft output of the engine A second generator that generates power by being driven by the motor, a bypass passage that bypasses the rotor and communicates with an intake passage upstream and downstream of the rotor, a bypass valve provided in the bypass passage, and a downstream side of the rotor Intake throttle means provided in an intake passage downstream from the junction of the intake passage and the bypass passage, means for detecting the required power of the vehicle, means for detecting the required intake air amount according to the driving state, and required intake Intake air amount control means for controlling the opening degree of the bypass valve and the intake throttle means according to the air amount, power generation amount control means for controlling the power generation amount of the first generator and the second generator, The The power generation amount control means uses the first generator in preference to the second generator, and when the required power of the vehicle is larger than the power generation possible amount of the first generator. the first generator added power lines that have according to the second of the generator, the intake air amount control means, intake air the intake throttle means using by priority over the bypass valve Adjust the amount .

  According to the present invention, the first generator that generates power by being driven by the suction negative pressure is preferentially driven, and the shaft output of the engine is output only when the electric power is insufficient only by the amount of power generated by the first generator. Since the power generation is performed by the second power generator driven by the power generator, the required power demand can be satisfied while maximizing the power generation efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of the system of this embodiment.
Reference numeral 1 denotes an engine, and reference numeral 4 denotes a generator driven by the shaft output of the engine 1 transmitted through a belt or the like.

  Reference numeral 3 denotes a generator connected to the rotor 2 provided in the intake passage 10 of the engine 1 via a shaft 9, and the rotor 2 connected via the shaft 9 makes the engine 1 operate at a low / medium load. It is driven by rotating due to the suction negative pressure generated when it is being operated to generate electricity. This means that energy that has conventionally been lost in the throttle unit that controls the intake air amount is recovered as electric power. The rotor 2 has the same structure as the blower (compressor) of the positive displacement supercharger. Further, as shown in the possible power generation amount map of FIG. 8, the power generator 3 has a power generation characteristic that the power generation possible amount becomes large when the engine 1 is operated at low and medium loads and the engine speed is high.

  The electric power generated by these generators 3 and 4 is used for the operation of the in-vehicle device or the battery 6 is charged.

  By the way, in view of energy efficiency, the generator 3 that uses energy that has been conventionally lost should be given priority over the generator 4 that uses engine output. Therefore, in the present embodiment, as will be described later, in principle, power is generated by the generator 3, and the generator 4 is operated when the required power of the vehicle cannot be satisfied by the generator 3 alone.

  The intake passage 10 is provided with a bypass passage 11 that bypasses the rotor 2 and flows intake air. The bypass passage 12 is provided with a bypass valve 12 that is opened and closed by a step motor or the like. The bypass valve 12 is closed. During the valve operation, the communication of the bypass passage 11 is blocked.

The intake passage downstream of the rotor 2 and the bypass passage downstream of the bypass valve 12 merge at the junction 14 . An intake throttle means 13 as an intake throttle means that is opened and closed by a step motor or the like is provided downstream of the merging portion 12 .

  The opening degree of the bypass valve 12 and the throttle valve 13 is controlled by a control unit (ECU) 5. The ECU 5 includes an intake air temperature sensor (not shown) for detecting the intake air temperature, a pressure sensor 7 for detecting the pressure downstream of the rotor 2, an engine cooling water temperature sensor (not shown) for detecting the engine cooling water temperature, and the accelerator opening degree. Each detection value such as an accelerator opening sensor (not shown) for detecting is input. Further, the detection value of the rotation sensor 8 for detecting the rotation speed of the shaft 9 and the pressure sensor 7 provided in the intake passage downstream of the rotor 2 is also input to the engine control unit (ECU) 5.

  Note that the pressure downstream of the rotor 2 can also be calculated from the rotational speed of the engine 1, the accelerator opening, the rotational speed of the rotor 2, and the like.

  In the present embodiment, since the generator 3 rotates at an arbitrary number of revolutions according to the power generation request, the amount of air passing through the rotor 2 always matches the amount of air satisfying the operation request of the engine 1. Not exclusively.

  Therefore, according to the flowchart of FIG. 9, the opening degree of the bypass valve 12 and the throttle valve 13 is controlled so as to satisfy the power generation request and the intake air amount request simultaneously. In this embodiment, the operation request of the engine 1 is compared with the actual operation state based on the pressure in the intake manifold without detecting the intake air amount. As a result, there is no need to provide an air flow meter or the like, the degree of freedom of layout in the engine room is increased, and the cost can be reduced.

  In step S500, the pressure (target intake pressure) in the intake manifold for generating the torque required by the engine 1 (hereinafter referred to as required torque) is calculated based on the detected value (accelerator opening signal) of the accelerator opening sensor. To do. Specifically, for example, first, the required torque is obtained from the accelerator opening using a map as shown in FIG. FIG. 10 is a map in which the required torque is assigned to the accelerator opening, and the required torque increases as the accelerator opening increases. Next, a target suction pressure is obtained from the required torque and the engine speed using a map as shown in FIG. FIG. 11 is a map in which the suction pressure is assigned to the required torque and the engine speed, and the suction pressure increases as the required torque increases and the engine speed increases.

  When the target suction pressure Pt is calculated, the process proceeds to step S510, and the actual suction pressure Pm detected by the pressure sensor 7 is read.

  In step S520, the target suction pressure Pt is compared with the actual suction pressure Pm, and if both are equal, the process ends. If they are not equal, the process proceeds to step S530, and it is determined whether or not the actual suction pressure Pm is higher than the target suction pressure Pt.

  When the target suction pressure Pt is higher, that is, when the intake air amount is insufficient, the process proceeds to step S540, and it is determined whether or not the throttle valve 13 is fully opened. If the throttle valve 13 is fully open, the bypass valve 12 can only be opened in order to increase the amount of intake air any more, so an open command is issued to the bypass valve 12 in step S550.

  If the throttle valve 13 is not fully open, the intake air amount can be increased by opening the throttle valve 13, so an opening command is issued to the throttle valve 13 in step S560.

  If the actual intake pressure is higher in step S530, that is, if the actual intake air amount is larger than the intake air amount required by the engine 8, the process proceeds to step S570 to determine whether the bypass valve 12 is fully closed. Make a decision.

  When the bypass valve 12 is fully closed, in order to reduce the intake air amount further, the opening degree of the throttle valve 13 has to be reduced, so a close command is issued to the throttle valve 13 in step S590.

  If the bypass valve 12 is not fully closed, the intake air amount can be reduced by closing the bypass valve 12, and therefore a close command is issued to the bypass valve 12 in step S580.

  As described above, in this embodiment, when the intake air amount is adjusted according to the operation request of the engine 1, the bypass valve 12 is kept closed as much as possible and the opening degree of the throttle valve 13 is changed. Control is made so that the bypass valve 12 is opened only when the throttle valve 7 alone cannot be adjusted.

  By controlling as described above, the amount of air required by the engine 1 can be satisfied while the generator 3 generates power.

  By the way, for example, when the air conditioner and the headlight are turned on and the power consumption is large and the bypass valve 12 is fully opened, the amount of air passing through the rotor 2 is reduced because the bypass valve 12 is fully opened, and the generator 3 There is a possibility that the required power cannot be satisfied with the amount of power generated. Therefore, in such a case, the generator 4 is operated to secure electric power.

  Here, the operation control of the generators 3 and 4 will be described.

  The ECU 5 performs control so that power generation by the generator 3 is prioritized as shown in the flowchart of FIG. Hereinafter, description will be given with reference to a flowchart.

  In step S100, the required power Wd of the vehicle is detected from the switch state of each device mounted on the vehicle.

  In step S110, the rotation speed Rc of the rotor 2 is detected from the detection signal of the rotation sensor 8.

  In step S120, the intake passage pressure Pc downstream of the rotor 2 is detected from the detection signal of the pressure sensor 7.

  In step S130, the power generation possible amount (hereinafter referred to as negative pressure power generation possible amount) Wg of the generator 3 is calculated as in the following equation (1).

Wg = coefficient × Rc × Pc (1)
In step S140, the required power Wd and the negative pressure power generation possible amount Wg are compared.

  If the required power Wd is larger, the process proceeds to step S150. In this case, since the required power Wd cannot be covered only by the negative pressure power generation, a power generation request command is issued to the generator 4 and the insufficient power is compensated by the power generation of the generator 4.

  If the required power Wd is smaller in step S140, the process proceeds to step S160. In this case, since it is possible to cover the required power Wd only by negative pressure power generation, a power generation stop command is issued to the generator 4.

  As described above, in the present embodiment, the generator 3 is driven with priority, and the generator 4 is driven only when the required power Wd of the vehicle cannot be covered by the negative pressure power generation possible amount Wg alone.

  That is, since the generator 3 that uses energy that has been lost as a pumping loss in the past can be driven preferentially and the drive of the generator 4 that uses the engine output can be minimized, the engine output loss Can be suppressed, and effects such as improvement in fuel consumption can be obtained.

  FIG. 6 shows a time chart when the above control is executed.

  Before t1, the generator 4 is stopped because the negative pressure power generation possible amount Wg is larger than the required power Wd. When the required power Wd increases at t1 and becomes larger than the negative pressure power generation possible amount Wg, the generator 4 is driven to generate power that is not sufficient only by the negative pressure power generation. When the required power Wd becomes smaller than the negative pressure power generation possible amount Wg again at t2, the generator 4 is stopped. Thereafter, similarly, the generator 4 is driven only when the required power Wd becomes larger than the negative pressure power generation possible amount Wg.

  As described above, in the present embodiment, the generator 3 that generates power using the suction negative pressure generated when the engine 1 is operating at a low / medium load, and the generator that generates power using the engine output. 4, only the generator 3 is driven when the suction negative pressure power generation possible amount Wg is larger than the required power Wd of the entire vehicle, and the generator 4 is driven only when the intake negative pressure power generation possible amount Wg becomes smaller. It can be minimized and effects such as improved fuel consumption can be obtained.

  The driving / stopping of the generator 4 may be gradually changed with a certain inclination instead of the ON / OFF control as shown in FIG. FIG. 7 shows a time chart when such control is performed.

  FIG. 7 is a time chart when the same control as in FIG. 6 is performed, but when the required power Wd becomes larger than the negative pressure power generation possible amount Wg at t1 and t3, the power generation amount gradually increases with a certain slope. When the required power Wd becomes smaller than the negative pressure power generation possible amount Wg at t2, the power generation amount gradually decreases with a certain slope.

  Thereby, since the rapid fluctuation | variation of the output of the engine 1 accompanying the drive / stop of the generator 4 can be suppressed, the torque shock etc. which a driver | operator feels can be suppressed.

  A second embodiment will be described with reference to FIG.

  The configuration and control of the system of this embodiment are basically the same as those of the first embodiment, but the part corresponding to steps S110 to S130 of FIG. 2, that is, the method of calculating the negative pressure power generation possible amount is different. Further, it is not necessary to provide the pressure sensor 7 for detecting the pressure in the intake passage downstream of the rotor 2.

  In step S200 corresponding to step S100, the required power Wd is detected as in step S100.

  In the present embodiment, the engine rotation speed N is detected in step S210 corresponding to step S110. For this, a detection value of a crank angle sensor or the like used for normal engine control can be used.

  In step S220 corresponding to step S120, the load F of the engine 1 is obtained from the engine intake air amount. The engine intake air amount can be calculated using sensors used for normal engine control, such as engine rotation speed and accelerator opening. It is also possible to perform measurement by providing an air flow meter in the intake passage.

  In step S230 corresponding to step S130, the engine power generation amount map of FIG. 8 is searched using the engine rotation speed and the load F determined above to determine the negative pressure power generation possible amount Wg.

  In the subsequent steps, the comparison with the required power Wd is performed as in the first embodiment, and the driving and stopping of the generator 4 are controlled.

  The time chart when the above control is executed is the same as FIG.

  As described above, in the present embodiment, as in the first embodiment, the generator 3 is preferentially driven and the drive of the generator 4 is minimized, so that the loss of engine output can be minimized. Effects such as improved fuel efficiency can be obtained.

  A third embodiment will be described with reference to FIG.

FIG. 4 is a diagram showing a control flow of the present embodiment, and this embodiment is similar to the second embodiment.
The parts corresponding to steps S110 to S130 of the first embodiment are different. Further, a sensor for detecting the current value and the voltage value of the generator 3 is provided without providing the pressure sensor 7 for detecting the pressure in the intake passage downstream of the rotor 2.

  In step S300 corresponding to step S100, the required power Wd is detected as in step S100.

  In step S310 corresponding to step S110, the current value (negative pressure generated current value) Ib of the generator 3 is detected.

  In step S320 corresponding to step S120, the voltage value (negative pressure generated voltage value) Vb of the generator 3 is detected.

  In step S330 corresponding to step S130, the negative pressure power generation possible amount Wg is calculated from the negative pressure power generation current value Ib and the negative pressure power generation voltage value Vb by the following equation (2).

Wg = Ib × Vb (2)
In the subsequent steps, similarly to the first embodiment, the required power Wd is compared with the first embodiment, and the driving and stopping of the generator 4 are controlled.

  The time chart when the above control is executed is the same as FIG.

  As described above, in the present embodiment, as in the first embodiment, the generator 3 is preferentially driven and the drive of the generator 4 is minimized, so that the loss of engine output can be minimized. Effects such as improved fuel efficiency can be obtained.

  A fourth embodiment will be described with reference to FIG.

  In this embodiment, the system configuration is basically the same as that of the first embodiment, but the current value flowing into the battery 6 is detected without providing the pressure sensor 7 for detecting the pressure in the intake passage downstream of the rotor 2. Provide a sensor.

  The control method is basically the same as in the first embodiment, but the method for determining whether to drive or stop the generator 4 is different. FIG. 5 is a diagram showing a control flow of the present embodiment, and will be described below according to the control flow.

  In step S400, the current value Ibt flowing from the generator 3 into the battery 6 is detected.

  In step S420, it is determined whether or not the current value Ibt is greater than zero. When the current value Ibt flowing from the generator 3 to the battery 6 is smaller than zero, that is, when all the electric power generated by the generator 3 is used for the operation of the in-vehicle device and the battery 6 is not charged, the step Proceeding to S420, the generator 4 is driven. If it is greater than zero, the battery 6 is also charged with the power generated by the generator 3, that is, the amount of power generated by the generator 3 is sufficient.

  Even when the above control is executed, the time chart is the same as in FIG.

  As described above, in the present embodiment, as in the first embodiment, the generator 3 is preferentially driven and the drive of the generator 4 is minimized, so that the loss of engine output can be minimized. Effects such as improved fuel efficiency can be obtained.

  The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the technical idea described in the claims.

  The present invention can be applied to an internal combustion engine including a generator that uses the suction negative pressure of the engine.

It is a figure showing the structure of the system of 1st Embodiment. It is a control flowchart of a 1st embodiment. It is a control flowchart of a 2nd embodiment. It is a control flowchart of a 3rd embodiment. It is a control flowchart of a 4th embodiment. It is a time chart at the time of performing 1st Embodiment. It is a time chart at the time of changing the drive / stop of the generator 4 gradually with a fixed inclination. 3 is a map of the power generation possible amount of the generator 3 It is a flowchart of opening and closing control of a bypass valve. It is the map which allocated torque to the accelerator opening. It is the map which allocated torque to engine speed.

Explanation of symbols

1 Engine 2 Rotor 3 Generator (driven by negative suction pressure)
4 Generator (driven by engine output)
5 Engine control unit (ECU)
6 Battery 7 Pressure sensor 8 Rotation sensor 9 Shaft 10 Intake passage

Claims (6)

A rotor interposed in an intake passage of the internal combustion engine;
A first generator connected to the rotor and generating electricity by rotating the rotor;
A second generator driven by the shaft output of the engine to generate electricity;
A bypass passage that bypasses the rotor and communicates with the intake passage upstream and downstream of the rotor;
A bypass valve provided in the bypass passage;
An intake throttle means provided in an intake passage downstream of the junction between the intake passage on the rotor downstream side and the bypass passage;
Means for detecting the required power of the vehicle;
Means for detecting the required intake air amount according to the operating state;
Intake air amount control means for controlling the opening of the bypass valve and the intake throttle means according to the required intake air amount;
Power generation amount control means for controlling the power generation amount of the first generator and the second generator,
The power generation amount control means includes:
Using the first generator in preference to the second generator;
When the required power of the vehicle is greater than the amount capable of generating power of the first generator, the generator lines gastric by the first generator in addition to the second generator,
The power generation system for an internal combustion engine, wherein the intake air amount control means adjusts the intake air amount by using the intake throttle means in preference to the bypass valve. The power generation amount control means comprises means for detecting the rotational speed of the rotor and means for detecting the pressure in the intake passage downstream of the rotor,
2. The power generation system for an internal combustion engine according to claim 1, wherein the power generation possible amount of the first generator is calculated by integrating the rotation speed of the rotor and the pressure in the intake passage downstream of the rotor. The power generation amount control means includes means for detecting the rotational speed of the engine and means for detecting the intake air amount of the engine,
2. The power generation system for an internal combustion engine according to claim 1, wherein the power generation possible amount of the first generator is calculated by performing a map search based on an engine speed and an intake air amount. The power generation amount control means includes means for detecting a current value and a voltage value of the first generator, and integrates a current value and a voltage value for the power generation possible amount of the first generator. The power generation system of the internal combustion engine according to claim 1 to calculate. The power generation amount control means includes means for detecting a current value flowing into the battery. When the current value is greater than zero, the power generation amount of the first generator is greater than the required power of the vehicle, and the current value is 2. The power generation system for an internal combustion engine according to claim 1, wherein when the power generation amount is smaller than zero, the power generation amount of the first generator is determined to be smaller than the required power of the vehicle. The power generation system for an internal combustion engine according to any one of claims 1 to 5, wherein the power generation control means gradually changes a power generation amount when generating power by the second generator.

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