JP2775882B2 - Control device for turbocharger with rotating electric machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for a turbocharger with a rotating electric machine in which a motor-generator is mounted on a rotating shaft of a turbocharger.

(Prior Art) Since exhaust gas of an internal combustion engine has a high temperature and a high pressure, various devices for recovering the exhaust gas energy as driving force or electric power have been conventionally proposed.

As an exhaust energy recovery device of this type, various attempts have been made to attach a rotating electric machine to be a motor-generator to a rotating shaft of an exhaust turbine shaft and drive the rotating electric machine as a motor or a generator according to the operating state of the engine. I have.

Proposals have been made to provide means for detecting the load of the engine and means for detecting the amount of depression of the accelerator pedal, and to control the supercharging means and the fuel supply means by the rotating electric machine based on signals from these means. It is disclosed in JP-A-63-272909.

(Problems to be Solved by the Invention) In the control device for a turbocharger with a rotating electric machine disclosed in the above-mentioned publication, in addition to the supercharging operation of the turbocharger by the exhaust energy when the engine is at a low rotational speed and a high load, etc. Meanwhile, electric power is supplied from a battery to a rotating electric machine, and the electric motor is run as an electric motor to increase the supercharging pressure, while increasing the fuel supply amount to increase the output of the engine.

However, during operation as such an electric motor, according to the depression amount of the accelerator pedal, for example, when the depression amount is the maximum, a large amount of electric power is supplied to the rotating electric machine, the rotation speed rises rapidly, and exceeds the allowable maximum rotation speed. In order to prevent this, the energization to the rotating electric machine is turned off before the limit is reached. Therefore,
When the power supply is cut off, the turbine rotation speed decreases, and when the power supply falls to a predetermined rotation speed, power is supplied again. For example, as shown in a turbine rotation control curve shown in FIG.
The fluctuation of the rotation speed like a triangular wave is repeated based on the allowable rotation speed of 120,000 rotations. For this reason, there is a disadvantage that the engine output also fluctuates, which adversely affects the running feeling of the vehicle.

The present invention has been made in view of such a conventional problem, and an object thereof is to control the fluctuation width of the rotation speed near the permissible rotation speed of the turbine to be small when electrically driving a rotating electric machine attached to a turbocharger. To provide a control device for a turbocharger with a rotating electric machine.

(Means for Solving the Problems) According to the present invention, in a control device for a turbocharger with a rotating electric machine that electrically drives a rotating electric machine attached to a turbine shaft to energize a supercharging pressure to an engine, And a control device for a turbocharger with a rotating electric machine that controls power supplied to the rotating electric machine according to a tendency of increase / decrease of the turbine shaft rotation speed when the rotation speed reaches a predetermined rotation speed near the upper limit rotation speed. .

(Operation) In the present invention, when the rotation speed of the turbine shaft reaches a predetermined rotation speed near the allowable rotation speed, the turbine rotation speed is detected to be increasing or decreasing, and if it is increasing, the power supplied to the rotating electric machine is detected. And in the case of a decreasing trend, the supply power is increased to control the rotation speed of the turbine shaft. Therefore, the vertical fluctuation width of the turbine speed is suppressed.

Example Next, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration block diagram showing one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a vehicle which is not shown driven by combustion energy of air taken in through an engine intake pipe 1a and fuel supplied from a fuel tank 1g through an injection pump 1f. The exhaust gas after combustion is discharged through the exhaust pipe 1b. Reference numeral 1c denotes an accelerator sensor serving as a means for detecting the amount of depression of an accelerator pedal, and 1e denotes a rotation sensor for detecting the number of revolutions of the internal combustion engine, and transmits the detected signals to a controller 6 described later.

Reference numeral 2 denotes a turbocharger connected to the exhaust pipe 1b and the intake pipe 1a. The turbocharger 2 includes a turbine blade 2b driven by exhaust gas, and a compressor blade 2a for pumping intake air to the intake pipe 1a. Rotating shaft 2c
Is mounted with a rotating electric machine 3 which operates as a motor or a generator.

The rotating electric machine 3 has a rotor 3a and a stator 3b. When the rotor 3a is rotationally driven by exhaust energy, the
The AC power is generated in 3b and transmitted to the battery 5 via the power converter 4.

When the rotor 3a is driven by the electric power from the battery 5 via the electric power converter 4, the compressor blade 2a
Is operated to compress the intake air and supercharge the internal combustion engine 1 via the intake pipe 1a. In addition, 1h is a boost sensor which detects the supercharging pressure due to the operation of the compressor blade 2a and transmits it to the controller 6.

The power converter 4 receives the AC power from the stator 3b when the generator is operating and converts the AC power into, for example, charging power for the battery 5 or converts the DC power from the battery 5 for driving the rotating electric machine 3 into an electric motor. It converts to electric power. Therefore, in addition to a rectifier circuit for converting AC to DC, a smoothing circuit, an inverter for converting DC to AC, a booster circuit, and the like, the AC frequency to be converted, its voltage, and power are controlled by a command from the controller 6. It is.

The controller 6 is composed of a microcomputer, a central processing unit that performs calculations such as fuel supply, required power, and boost pressure based on the operating state of the internal combustion engine 1 and signals from various sensors, a memory of the results of these calculations, And a memory device for storing a control program for the rotating electrical machine, and an input / output device for receiving various inputs and issuing control instructions to related parts. The rotation speed of the turbine shaft is input to the controller 6 based on the frequency of the back electromotive force induced in the stator 3b when the rotating electric machine 3 rotates.

FIG. 2 is a processing flowchart showing an example of the operation of the present embodiment, and the operation will be described with reference to FIG.

In step 1, it is determined from the signal of the accelerator sensor 1c whether or not the amount of depression is the maximum. If the pedal is fully depressed, the flow proceeds to step 2, and if not, the flow proceeds to step 5.

When proceeding to step 5, target boost pressure value (P _t )
If the difference between the pressure difference and the actual boost pressure value (P _B ) is larger than the acceleration determination boost differential pressure (K _B ) (acceleration state), the process proceeds to step 9 and the current value I to be supplied to the inverter of the power converter 4 Calculate _inv . Also, if P _t -P _B is small in Step 5 and the flow proceeds to the mode decision step 10.

When the accelerator pedal is depressed to the maximum and the process proceeds from step 1 to step 2, the turbine rotational speed is obtained from the frequency of the back electromotive force from the stator 3b of the rotating electric machine 3, and the turbine rotational speed is lower than the predetermined rotational speed. When the rotational speed is lower than L _rpm, the process proceeds to step 3 and the current value I _inv to the inverter is set to the maximum value.
Set I _max, for the electric drive to turn on the inverter at step 4. If the turbine rotation speed is equal to or higher than the low rotation speed L _rpm in step 2, the process proceeds to step 6, where the turbine rotation speed is compared with a high rotation speed H _rpm of a predetermined rotation speed, and the high rotation speed H _rpm is determined. If it is below _rpm , proceed to step 7; if it is above _rpm , proceed to step 11 to turn off the inverter and stop energization. When the process proceeds to step 7 at the high-side rotation speed H _rpm or lower, it is determined from the frequency of the electromotive force whether the turbine rotation is increasing or decreasing. If the frequency is increasing and the rotation speed is increasing, step 8 is performed. And the current value I _inv to the inverter
Is decreased by a predetermined value i, and the routine proceeds to step 4 to operate the inverter.

If it is determined in step 7 that the current value is decreasing, the current value is kept as it is in step 12 and the inverter is turned on in step 4.

Therefore, by performing the processing shown in FIG. 2, when the rotation speed of the turbine is equal to or less than L _rpm , the rotation speed is increased by maximizing the input current of the inverter, and the rotation speed of the turbine is reduced.
In the case of L _rpm or more, the current to the inverter is limited according to the tendency of the increase or decrease of the turbine speed, and control is performed so as to suppress the fluctuation of the turbine speed.

As described above, the present invention has been described with the above-described embodiments. However, various changes can be made within the scope of the gist of the present invention, and these changes are not excluded from the scope of the present invention.

(Effect of the Invention) According to the present invention, a high-side rotation speed H _rpm and a low-side rotation speed L _rpm are provided before and after the upper limit value of the turbine speed of the turbocharger, and when the accelerator pedal is fully depressed, Compare the turbine speed with the high-side speed or low-side speed.If the speed is lower than the low-side speed, the current to the inverter is maximized. Since the current value is controlled and supplied to the inverter according to the tendency of increase or decrease, the remarkable fluctuation of the turbine speed as in the past can be suppressed, while the engine speed increases when the turbine speed decreases. As the exhaust energy increases, the turbine speed may start to increase.Therefore, in conjunction with the control of the inverter current, the turbine speed becomes a fixed speed between the high side and the low side. When numbers converge Effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a process flow chart showing an example of the operation of this embodiment, FIG. 3 is a curve diagram of turbine rotation control in this embodiment, and FIG. 4 is a curve diagram of turbine rotation control in control of a conventional turbocharger. DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Turbocharger, 3 ... Rotary electric machine, 4 ... Power converter, 5 ... Battery, 6 ... Controller, 2b ... Turbine blade, 2c ... Rotary shaft.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02B 33/00-39/16

Claims (1)

(57) [Claims] 1. A control device for a turbocharger with a rotating electric machine for electrically driving a rotating electric machine mounted on a turbine shaft to apply a supercharging pressure to an engine, wherein the turbine shaft has a predetermined rotation speed near its upper limit rotation speed. A controller for a turbocharger with a rotating electric machine, wherein the controller controls the power supplied to the rotating electric machine in accordance with the tendency of increase / decrease of the turbine shaft rotation speed when the rotation speed reaches the rotation speed.