JP3389748B2 - Exhaust energy recovery device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust energy recovery apparatus for recovering energy by rotating a rotating electric machine provided in a turbocharger by using exhaust gas. [0002] In a turbocharger of a turbo car, a turbine is rotated by exhaust gas to promote the suction of the atmosphere. However, the exhaust gas after starting the vehicle and shifting to normal running rotates the turbine. Even after being let go, it still has enough energy. Therefore, a device has been considered in which a rotating electric machine is attached to a turbocharger and the exhaust energy is further recovered. FIG. 8 is a diagram showing a configuration of such an exhaust energy recovery device. 8, 1 is a vehicle generator, 11 is a turbocharger rotating electric machine, 11-1 is a rotor, 11-2 is a stator, 13 is a battery, 20 is a pulley, 21 is an engine, 22 is an intake pipe, and 23 is Exhaust pipe, 2
4 is a belt, 25 is a pulley, 26 is a turbocharger,
27 is a compressor blade, 28 is a turbine blade, and 29 is an electric load. The pulley 20 is connected to the shaft of the engine 21, and the pulley 25 is connected to the shaft of the vehicle generator 1. The pulleys 20 and 25 are connected by a belt 24. The turbocharger rotating electric machine 11 is provided in the turbocharger 26, and its rotor 1
1-1 is connected to the rotating shafts of the compressor blade 27 and the turbine blade 28 of the turbocharger 26, and the stator 11-2 is fixed inside the turbocharger 26. As the turbocharger rotating electric machine 11, a synchronous machine is used, and as described below, the generator is operated or the motor is operated as occasion demands. The electric power generated by the vehicle generator 1 is used to charge the battery 13 and supply power to the electric load 29, as is well known, but when the turbocharger 26 has a weak turbo action (the boost pressure is still small) at the time of starting. For example, power is also supplied to the turbocharger rotating electric machine 11. The turbocharger rotating electric machine 11 supplied from the vehicle generator 1 operates as a motor, assists the rotation of the compressor blade 27 and the turbine blade 28, promotes the turbo action, and increases the engine torque. When the energy of the exhaust gas is large, the turbocharger rotating electric machine 11 is operated by a generator, and the generated electric power is used to charge the battery 13 or to charge the electric load 2.
9 for power supply. In some cases, it is also supplied to the vehicle generator 1, and the vehicle generator 1 is driven by a motor.
The motor generator-driven vehicle generator 1 applies torque to the engine 21 to reduce fuel consumption. FIG. 9 is a block diagram of a conventional exhaust energy recovery device. Reference numerals correspond to those in FIG. 8, 2 is an inverter rectifier circuit, 3 is a rectifier circuit, 4 is an inverter, 5
Is a smoothing circuit, 6 is a booster circuit, 7 is a smoothing circuit, 8 is an inverter rectifier circuit, 9 is an inverter, 10 is a rectifier circuit, 11
Is a turbocharger rotating electric machine, 12 is a position sensor, 14 is a regulator, 15 is a switching circuit, and 16 is a control unit. [0007] The booster circuit 6 boosts and applies the generated voltage of the vehicle generator 1 when the turbocharger rotating electric machine 11 is driven by a motor. Generally, the rotation speed of the turbocharger rotating electric machine 11 is much higher than that of the vehicle generator 1, and the induced voltage is large. Therefore, in order to operate the turbocharger rotating electric machine 11 by motor, it is necessary to apply a voltage larger than the induced voltage, but the generated voltage of the vehicle generator 1 may not reach the value. Therefore, the voltage is boosted by the booster circuit 6 and applied. The configuration of the booster circuit 6 is a known booster circuit using a switching transistor. The inverter rectifier circuits 2 and 8 are circuits that at one time perform the role of an inverter and at other times perform the role of a rectifier circuit. One example of the configuration is shown in FIG. 3 described later. The position sensor 12 is a sensor that detects a magnetic pole position of a rotor of the turbocharger rotating electric machine 11 that is a synchronous machine. Position sensor 12
The number of rotations can also be detected based on the signal from. The control unit 16 receives signals from the position sensor 12 as well as vehicle information (eg, accelerator opening, engine speed, etc.) from various sensors and switches. Then, as shown by the dotted line, the control circuit issues a signal for controlling the inverter rectifier circuit 2, the booster circuit 6, the inverter rectifier circuit 8, and the regulator 14. The generated voltage of the vehicle generator 1 is rectified by the rectifier circuit 3, smoothed by the smoothing circuit 5, and
The output voltage V _P to appear. Similarly, the voltage generated by the turbocharger rotating electric machine 11 is rectified by the rectifier circuit 10,
The output voltage V _Q appears at the point Q after being smoothed by the smoothing circuit 7. The output voltages V _P and V _Q of each smoothing circuit are input to the switching circuit 15, and the higher voltage is selected and output to the regulator 14. The regulator 14 controls the voltage from the switching circuit 15 to a voltage suitable for charging the battery 13 or supplying power to an electric load. Its configuration is, for example, a switching transistor,
It is a known device including a transformer, a rectifying / smoothing circuit, and the like (see a portion indicated by reference numeral 14 in FIG. 3 described later). FIG. 2 is a diagram showing a region where a torque increase is required and an energy recovery region in the engine. The horizontal axis represents the engine speed, and the vertical axis represents the turbocharger speed. The rotation speed of the vehicle generator 1 is determined by the engine rotation speed and the rotation speed ratio of the pulleys 20 and 25.
A curve a indicates a change in the turbocharger rotation speed when the turbocharger rotating electric machine 11 is not operated by the motor or the power generation operation. The torque increase required area A, which is indicated as an area where the engine speed is lower than N _1, is an area where the boost pressure is low and the engine torque is low only when the turbocharger 26 is rotated only by the energy of the exhaust gas. It is. In this region, a torque increase is required. Engine speed N ₁ is different depending on the type of engine (e.g., 900 rpm). The curve B shows a change when the turbocharger rotating electric machine 11 is driven by a motor to increase the torque and the turbocharger rotation speed is increased. When the turbocharger rotating electric machine 11 is driven by a motor, the electric power generated by the vehicle generator 1 is supplied through a route of the rectifier circuit 3 → the smoothing circuit 5 → the booster circuit 6 → the inverter 9 → the turbocharger rotating electric machine 11. The energy recovery region B, which is indicated as a region where the engine speed is higher than N _2, is a region where the boost pressure becomes unnecessarily high when the turbocharger 26 is rotating with the energy of the exhaust gas. And
In this region, extra energy can be recovered. Engine speed N ₂ depends on the type of engine (e.g., 1300 rpm). A curve C shows a change when the turbocharger rotating electric machine 11 is operated as a generator for energy recovery and the turbocharger rotation speed is reduced. The power generated by the turbocharger rotating electric machine 11 is supplied to the rectifier circuit 10 → smoothing circuit 7 → switching circuit 15 → regulator 1
4 and a rectifier circuit 10 → smoothing circuit 7 → inverter 4 →
There is also a case where the electric power is supplied to the vehicle generator 1 through the route of the vehicle generator 1. Thus, the energy of the exhaust gas is recovered as electrical energy and mechanical energy. As a conventional document relating to an exhaust energy recovery apparatus, there is, for example, Japanese Patent Application Laid-Open No. 5-152919. In the prior art described above, in order to guide either the generated voltage of the vehicle generator 1 or the generated voltage of the turbocharger rotating electric machine 11 to the regulator 14, the selection is switched. There is a problem that a switching circuit 15 for performing the switching is required. As the switching circuit 15,
There are circuits using contact relays and circuits using non-contact switch elements (eg, thyristors). However, they must be provided in any case, which increases the cost. There is also a disadvantage that the non-contact type is not efficient. An object of the present invention is to solve such a problem. In order to solve the above-mentioned problems, an exhaust energy recovery apparatus according to the present invention is provided with a vehicle generator and a turbocharger. The turbocharger rotating electric machine that is driven and the generator is operated when the energy of the exhaust gas is large, and is provided corresponding to each of the vehicle generator and the turbocharger rotating electric machine. An inverter rectifier circuit that is operated as an inverter and operates as a rectifier circuit or a step-up chopper when the generator is operated; and a smoothing circuit that is provided corresponding to each of the inverter rectifier circuits and smoothes a DC output voltage of the inverter rectifier circuit. The circuit and the output terminal of the smoothing circuit are collectively connected to the input terminal, and the input voltage is reduced to the battery voltage. A regulator that performs pressure control, and among the rectified and smoothed voltages generated by the vehicle generator and the turbocharger rotating electric machine, when the smoothed voltage on the side to which power is to be supplied to the regulator is lower than the other smoothed voltage, Control means for controlling the voltage of the inverter rectifier circuit to be higher so as to be higher. [Operation] In an exhaust energy recovery apparatus provided with a turbocharger rotating electric machine in addition to a vehicle generator,
The smoothing voltage of the generated voltage of the vehicle generator and the turbocharger rotating electric machine is input collectively to a regulator that controls the voltage down to the battery voltage in order to charge the battery or supply power to the on-vehicle electric load. If the smoothed voltage on the side to be supplied to the regulator is lower than the other smoothed voltage, the corresponding inverter rectifier circuit is boosted so as to be higher than the other smoothed voltage. By controlling the magnitude relationship of the smoothed voltages in this manner, it is possible to supply the generated voltage on the desired side to the regulator without the need for a switching circuit. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of the exhaust energy recovery apparatus of the present invention, and the reference numerals correspond to those of FIG. The first point of the configuration different from the conventional example of FIG. 9 is that the switching circuit 15 is eliminated. Therefore, the output terminals (point P) of the inverter rectifier circuit 2 and the smoothing circuit 5 provided for the vehicle generator 1 and the output terminals of the inverter rectifier circuit 8 and the smoothing circuit 7 provided for the turbocharger rotating electric machine 11 (point P). And the point Q) are connected collectively and connected to the input side of the regulator 14. In this case, the higher one of the voltages appearing at the points P and Q becomes the input of the regulator 14. The second difference is that the booster circuit 6 is eliminated. Since the boost pressure detection signal and the engine speed signal are included in various "vehicle information" even in the conventional example shown in FIG. 9, the boost pressure sensor and the engine speed sensor are used to detect them. However, in the present invention, there is a portion which is particularly described in relation to the boost pressure (FIG. 7), and the engine speed is used in the control of FIG. The rotation speed sensor 18 is also shown in FIG. Although the configuration of the inverter rectifier circuits 2 and 8 is the same as that of the conventional example shown in FIG. 9, the present invention differs in the usage. That is, when processing the generated voltage, there are a case where only the rectification circuit portion is used only for rectification as in the related art, and a case where the rectification circuit and the inverter portion are used together to operate as a step-up chopper. The boosting is performed when the voltage which is simply rectified and smoothed is lower than the smoothed voltage from the other party, but the power supply to the regulator 14 is desired to be performed by itself. Such a case will be described later with reference to FIG. FIG. 3 is a diagram showing a specific circuit of the exhaust energy recovery apparatus of the present invention, and the reference numerals correspond to those of FIG. 14-1 is a switching transistor, and 19A and 19T are reactors. The inverter rectifier circuits 2 and 8 are known circuits each including a three-phase bridge-connected switching element (eg, a transistor) and a diode connected in anti-parallel to the switching element. This circuit can convert a DC voltage applied from the DC terminal side into an AC voltage, and can also convert (rectify) an AC voltage (power generation voltage) applied to the AC side into a DC voltage. However, the present invention is characterized in that the inverter rectifier circuits 2 and 8 are operated as boost choppers in a specific case by using a reactor existing on the AC side. Next, a boost chopper will be described using the inverter rectifier circuit 2 as an example. FIG. 4 is a diagram showing a connection relationship between the inverter rectifier circuit 2 and the stator winding of the vehicle generator 1. The reference numerals correspond to those in FIG.
Reference numerals -1 and 2-2 denote transistors which are switching elements for a certain phase, reference numerals 2-3 and 2-4 denote diodes connected in anti-parallel to the transistors, and reference numerals 2-5 and 2-6 denote terminals. . When operating as a step-up chopper, chopping is performed by turning on and off the switching transistors connected in the direction in which the generated current flows out of the switching transistors constituting the inverter rectifier circuit 2. The other switching transistor is kept off. For example, with respect to the generated current from the stator winding 1-1, the transistor 2-2 connected in the direction in which the current flows is controlled to be on and off, and the other transistor 2-1 is kept off. Then, a current I ₁ flows during on of the transistor 2-2, a current flows I ₂ through the diode 2-3 during off. FIG. 5 is a diagram showing an example of a circuit portion operating as a step-up chopper. Symbols correspond to those in FIG. 4, 2-7 and 2-8 are terminals, V _IN is an input voltage,
V _OUT is the output voltage. A known boost chopper using a switching transistor requires a reactor for storing electromagnetic energy on the input side, but the stator winding 1-1 for generating a voltage also functions as the reactor. If the shortage still occurs, as shown in FIG. 3, a reactor 19A may be connected to each phase line between the vehicle generator 1 and the inverter rectifier circuit 2 (the reactor 19T in FIG. The turbocharger rotating electric machine 11 is connected for the same reason.) During the period when the transistor 2-2 is turned on,
Current I ₁ flows through a path shown by dashed-line arrow. The off time period, the electromagnetic energy stored in the stator winding 1-1 in the period of ON, the current I ₂ flows in the path indicated by dotted arrows. FIG. 6 is a waveform diagram of the current and the like of the step-up chopper of FIG. FIG. 6A shows a switching signal for turning on and off the transistor 2-2. The switching frequency of this signal is much higher than the frequency of the generated voltage from the vehicle generator 1 (eg, about the carrier frequency). Then, the change in the generated voltage in a short time of one cycle of the switching signal is extremely small, and the input voltage V _IN during that time can be considered almost the same as the DC voltage. FIGS. 6B and 6C show the currents I ₁ and I ₂ , and FIG.
_Shows the waveform of the output voltage V _OUT . The output voltage V _OUT output from the inverter rectifier circuit 2 is smoothed by the smoothing circuit 5 in FIG. FIG. 7 is a diagram showing the relationship between the boost pressure and the power supply to the regulator. _VP is the voltage at point _P in FIG. 1 (smoothed voltage of the generated voltage from the vehicle generator 1), _VQ is the voltage at point _Q in FIG. 1 (smoothed voltage of the generated voltage from the turbocharger rotating electric machine 11), V _PU and V _QU are voltages at points P and Q when the inverter rectifier circuits 2 and 8 are operated as boosting choppers, respectively. FIGS. 7A to 7D respectively show the following four items.
The type is shown. FIG. 7A shows a case where the regulator 14 is supplied with power from the vehicle generator 1 when the boost pressure is higher than a desired value. FIG. 7B: When the boost pressure is higher than a desired value, the turbocharger rotating electric machine 1
When supplying power from 1. FIG. 7C: When the boost pressure is lower than the desired value, the power is supplied from the vehicle generator 1 to the regulator 14. FIG. 7D shows that when the boost pressure is lower than the desired value, the turbocharger rotating electric machine 1 is supplied to the regulator 14.
When supplying power from 1. When the boost pressure is high due to the operation of the turbocharger 26, the rotation speed of the turbocharger rotating electric machine 11 is also high, and V _Q > V _P. However, depending on the operating condition of the engine, when the turbocharger rotating electric machine 11 attempts to supply power to the regulator 14, there are cases where the engine torque immediately decreases and cases where it does not. When the engine torque decreases, the inverter rectifier circuit 2 is operated as a boost chopper as shown in FIG. 7A to supply power from the vehicle generator 1, and the voltage at the point P is set to V _PU higher than V _Q. And That way, naturally V _PU is employed as the input of the regulator 14, the regulator 14 from the vehicle generator 1
Power is supplied to However, even when power is supplied from the turbocharger rotating electric machine 11 to the regulator 14, the inverter rectifier circuit 2 is not operated as a step-up chopper in an operating condition in which the engine torque does not decrease. Since V _Q > V _P , the higher V _Q is adopted as the input of the regulator 14, and power is supplied from the turbocharger rotating electric machine 11 to the regulator 14. If the operation of the turbocharger 26 is not sufficient and the boost pressure is low, the turbocharger rotating electric machine 1
1 is also low, and V _P > V _Q. With this voltage as it is, the higher _VP is adopted as the input of the regulator 14, and power is supplied from the vehicle generator 1 to the regulator 14. However, depending on the operating conditions of the engine,
There are cases where it is desired to supply power to the regulator 14 from the turbocharger rotating electric machine 11. In that case, the inverter rectifying circuit 8 boosts chopper operation as shown in FIG. 7 (d), the voltage of the point Q and the higher V _QU than V _P. Then, V _QU is adopted as an input of the regulator 14, and power is supplied from the turbocharger rotating electric machine 11 to the regulator 14. FIG. 10 is a flow chart for explaining the operation in the case of increasing the generated voltage of the vehicle generator in the present invention. Step 1: It is checked whether or not the operating state of the engine is in the torque increase necessary area A of FIG. This is because the engine speed detected by the engine speed sensor 18 is N _{1 in} FIG.
Check by whether it is smaller. If it is not in the torque increase required area A, the pressure is not boosted. Step 2... If the vehicle is in the torque increase required area A, the battery 13 must not be charged by supplying power to the regulator 14 from the turbocharger rotating electric machine 11. In this case, preparations are made to increase the power generation voltage of the vehicle generator 1 and supply power to the regulator 14. First, based on a detection signal from the position sensor 12, the rotation speed _NT of the turbocharger rotating electric machine 11 is determined.
Ask for. Step 3 ... based on N _T, calculates a generated voltage V _T of the turbocharger rotating electric machine 11 (of course, the power generation voltage is calculated as a value proportional to the rotational speed.). Step 4: The calculated smoothed value of the generated voltage V _T (= √2V _T, which is nothing less than the voltage V _Q at the output point Q of the smoothing circuit 7) is applied to the smoothed voltage ( V _P, the larger of the V _Q) over whether investigate. If that were lower than the input smoothed voltage, towards V _P it is because none other than that is input to the regulator 14, and is powered from the vehicle power generator 1 to the regulator 14. Therefore, there is no need to boost. In the case that was Step 5 ... input smoothed voltage or more, because none other than that towards the V _Q are inputted to the regulator 14, to power the vehicle generator 1 to the regulator 14, by boosting the power generation voltage of the vehicle generator 1 must be higher than V _Q. Therefore, a voltage higher than V _Q by an appropriate amount (eg, 10 V)
Set as the boost target voltage. Step 6: The inverter rectifier circuit 2 is operated as a step-up chopper, and the generated voltage of the vehicle generator 1 is stepped up. As a result, the regulator 14 is supplied with a smoothed voltage from the smoothing circuit 5. As described above, according to the exhaust energy recovery apparatus of the present invention, the regulator that controls the voltage of the vehicle to the battery voltage in order to charge the battery or supply power to the vehicle-mounted electric load is provided. The smoothing voltage of the voltage generated from the rotating machine and the turbocharger rotating electric machine is input collectively. If the smoothing voltage on the side to be supplied to the regulator is lower than the other smoothing voltage, the other The corresponding inverter rectifier circuit is boosted so as to be higher than the voltage. By controlling the magnitude relationship of the smoothed voltages in this manner, the generated voltage on the desired side is supplied to the regulator, so that a special switching circuit is not required.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an exhaust energy recovery device of the present invention. FIG. 2 is a diagram showing a torque-up required area and an energy recovery area. FIG. FIG. 4 is a diagram showing a circuit. FIG. 4 is a diagram showing a connection relationship between an inverter rectifier circuit and a stator winding of a vehicle generator. FIG. 5 is a diagram showing a circuit portion operating as a step-up chopper. FIG. 7 is a diagram showing a relationship between a boost pressure and a power supply to a regulator. FIG. 8 is a diagram showing a configuration of an exhaust energy recovery device. FIG. 9 is a conventional exhaust energy recovery device. FIG. 10 is a flowchart for explaining the operation of the present invention when boosting the generated voltage of the vehicle generator. [Description of References] 1 ... Vehicle generator, 2 ... Inverter rectifier circuit, 3 ... Regulation Circuit, 4 ... inverter, 5 ... smoothing circuit, 6 ... the booster circuit, 7
... Smoothing circuit, 8 ... Inverter rectifier circuit, 9 ... Inverter, 10 ... Rectifier circuit, 11 ... Turbocharger rotating electric machine, 11-1 ... Rotor, 11-2 ... Stator, 12 ... Position sensor, 13 ... Battery, 14 …regulator,
15 switching circuit, 16 control unit, 17 boost pressure sensor, 18 engine speed sensor, 19A, 19T reactor, 20 pulley, 21 engine, 22 intake pipe, 23 exhaust pipe, 24 belt , 25 ... pulley, 26
... turbocharger, 27 ... compressor blade, 2
8 Turbine blade 29 Electric load

Claims (1)

(57) [Claims] [Claim 1] A vehicle generator and a turbocharger are provided, and a motor is operated when the turbo action is insufficient, and when the energy of exhaust gas is large, A turbocharger rotating electric machine driven by a generator is provided corresponding to each of the vehicle generator and the turbocharger rotating electric machine, and operates as an inverter when the motor is operated, and a rectifier circuit or a rectified circuit when the generator is operated. An inverter rectifier circuit that operates as a boost chopper, and a smoothing circuit that is provided corresponding to each of the inverter rectifier circuits and smoothes a DC output voltage of the inverter rectifier circuit.
An output terminal of the smoothing circuit is collectively connected to an input terminal, and the regulator controls the input voltage to step down to a battery voltage, and the regulator includes a rectified and smoothed voltage generated by the vehicle generator and the turbocharger rotating electric machine. Control means for boosting the corresponding inverter rectifier circuit so that when the smoothed voltage on the side to which power is to be supplied to the other is lower than the other smoothed voltage, the corresponding boosted voltage is higher than the other smoothed voltage. .