JP3094560B2 - Engine with turbocharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an engine provided with a turbocharger driven by exhaust energy of the engine.

[0002]

2. Description of the Related Art Generally, when controlling the supercharging pressure of an engine equipped with a turbocharger, a wastegate provided in an exhaust passage bypassing the turbocharger communicating with an exhaust manifold is provided. Is opened and closed to control only the maximum pressure. The waste gate is a relief valve that reduces the intake pressure by releasing a kind of exhaust gas to the outside, and is provided upstream of the turbine of the turbocharger to bypass the turbocharger.

For example, in an engine provided with a turbocharger, a supply pressure map, that is, a boost pressure map is as shown in FIG. In FIG. 4, the horizontal axis represents the engine speed rpm, ie, the engine speed N, and the vertical axis represents the torque, ie, the engine load L. Due to the structure of the engine, if the maximum boost pressure is 500 mmHg,
Open the waste gate at 0 mmHg. At this time, the waste gate is opened using the pressure on the intake boost side. Suppose the engine speed, that is, the engine speed N
Is N _X , the supercharging pressure of the engine at the rotation speed N _X is 500 mm, regardless of the engine load L.
It is configured to be operated at Hg.

[0004] Conventionally, as a driving device of a turbocharger with a rotating electric machine, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 2-30925. The drive device of the turbocharger with the rotating electric machine connects two turbochargers equipped with the rotating electric machine in series to the exhaust passage of the engine in series, and also connects the supercharged passages of these turbochargers in series to the engine. In addition to supplying compressed air, the rotary electric machine is driven as an electric motor in accordance with an operation range of the engine at a low speed and a high load.

[0005]

Incidentally, the N contained in the exhaust gas from an engine equipped with a turbocharger is known.
O _X amount and the engine output P is as shown in FIG. In Figure 5, it takes the torque that is, the engine load L is plotted on the horizontal axis, and taking the amount of NO _X and the engine output P on the vertical axis contained in the exhaust gas. Engine load L, in FIG. 5, is divided into regions of low load L _L regions, medium load L _M region and high load L _H. As shown in FIG. 5, when the engine is operated at the maximum boost pressure 500 mmHg, amount and the engine output P of the exhaust gas of the NO _X is as shown by the solid line. Further, when the engine is operated in the boost pressure 400 mmHg, amount and the engine output P of the exhaust gas of the NO _X is as shown by a dotted line. Furthermore, if the engine has a boost pressure of 300
When operated in mmHg, content and engine output P of the exhaust gas of the NO _X is as shown by a two-dot chain line.

In an engine equipped with a turbocharger,
For example, as can be seen from FIG. 5, the generation of the NO _X amount with respect to the engine load L is reduced when the boost pressure is 300 mm.
Although when in operating at Hg, without reducing much the engine output P, best boost pressure P _b to reduce the generation amount of the NO _X when the engine load L is high load L _H 50
Is a 0mmHg, when the medium load L _M is 400mmHg, when the medium load L _L is 300mmHg.

It is an object of the present invention, as described above, considering that the boost pressure of the best that can reduce the emissions of the NO _X in accordance with the engine load and the engine speed is present, according to the engine load and engine speed The target supercharging pressure is set or set in accordance with a preset boost pressure map, and the rotating electric machine provided in the turbocharger is operated as a generator so as to achieve the target supercharging pressure, and the amount of power generated by the generator is controlled. controls boost圧即Chi boost pressure Te, is to provide an engine equipped with a turbocharger suppressing generation of the NO _X while maintaining the engine output.

[0008]

SUMMARY OF THE INVENTION The present invention provides an exhaust manifold which communicates with an exhaust port formed in a cylinder head.
A turbocharger having a rotating electric machine communicating with the exhaust manifold through an exhaust passage, a sensor for detecting an operation state of an engine, and the rotating electric machine operating as a generator in response to a detection signal of the sensor, and generating electricity of the rotating electric machine. A controller for controlling the supercharging pressure by controlling the amount in accordance with the operating state of the engine, wherein the controller controls the rotating electric machine so as to obtain an optimum supercharging pressure according to the engine speed and the engine load according to a preset boost pressure map. The present invention relates to an engine provided with a turbocharger that controls the amount of power generated by a turbocharger.

Also, the present invention provides an exhaust manifold communicating with an exhaust port formed in a cylinder head, a turbocharger having a rotating electric machine communicating with the exhaust manifold through an exhaust passage, a sensor for detecting an operating state of an engine, and the sensor. A controller that operates the rotating electric machine as a generator in response to the detection signal, and controls a supercharging pressure by controlling a power generation amount of the rotating electric machine in accordance with an operation state of the engine. A target supercharging pressure is set according to a preset boost pressure map corresponding to the load, and the target supercharging pressure is compared with the actual supercharging pressure detected by the sensor. The present invention relates to an engine provided with a turbocharger comprising controlling the amount of power generated by the rotating electric machine so as to obtain a pressure.

[0010] In a state engine with a turbocharger, which is configured as described above, which can be controlled boost pressure optimal for suppressing the generation of NO _X, maintaining the engine output, NO _X generation can be suppressed. In particular, the controller, and controls the power generation amount operates as a generator the rotary electric machine so as to optimize the boost pressure according to the engine speed and engine load in accordance with the boost pressure map is set in advance, of the NO _X generation the can be controlled to the optimum supercharging pressure can be reduced, for example, at the time of low load controlled to follow the power generation amount of the electric rotating machine to a boost pressure map, and reduce the supercharging pressure by reducing the turbine speed of the turbocharger, NO _X The occurrence of is reduced. Also,
At medium and high loads of the engine, the turbocharger power generation is made to follow the boost pressure map, and the turbocharger is accelerated to increase the compressor operation to increase the boost pressure and maintain the engine output. , N
To reduce the occurrence of O _X.

The engine equipped with this turbocharger follows a preset boost pressure map corresponding to the engine speed N and the engine load L as shown in FIG. When the engine speed N is low rotation (e.g., when the engine speed is N ₁₎ in order exhaust gas energy from the engine is small, (in the figure, a point of 350 mmHg) the boost pressure in the high-load side pressure becomes, On the low load side, the boost pressure is low (in the figure, 200 mmHg b
Point), and basically follows the boost pressure map that should be the present invention. However, when the engine speed N is high rotation (e.g., when the engine speed is N _2), the boost pressure is conventionally in the low-load side of the point c is as shown by the dotted line, since the pressure of 450mmHg is added , in the present invention by the boost pressure map the boost pressure is lowered to 200 mmHg, allowing the operation with suppressing the occurrence of NO _X. In the present invention, the target boost pressure is determined as described above.

[0012] For example, as shown in FIG. 5, the engine load L is low load L _L sometimes supercharging pressure operated as a generator to the rotary electric machine so as to 300 mmHg, medium load L _M times supercharging pressure 400mmHg so that by operating the compressor in the power generation amount of the turbocharger increases the boost pressure, a higher load L _H sometimes boost pressure to operate the compressor in the power generation amount of the turbocharger to be 500mmHg supercharging pressure And the amount of generated NO _X is reduced. That is, sometimes the low load L _L, by driving the boost pressure at 300 mmHg, the engine output P and NO _X generation amount follows a two-dot chain line. Sometimes medium load L _M, if operating the supercharging pressure at 400 mmHg, the engine output P and NO _X generation amount follows the dotted line. Also, sometimes a high load L _H, boost pressure when operating at 500 mmHg,
The engine output P and the NO _X generation amount follow the solid line. Therefore, in the entire operating range of the engine, without hardly reducing the engine output P, it can be greatly reduced generation of NO _X.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an engine having a turbocharger according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic explanatory view showing an embodiment of an engine equipped with a turbocharger according to the present invention, FIG. 2 is a processing flow chart showing an embodiment of the operation of an engine equipped with a turbocharger according to the present invention, and FIG. invention graph showing the generation amount to output relationship of the NO _X corresponding to the engine load of the engine and a conventional engine with a turbocharger according to the graph Figure 4 which shows the relationship between the engine speed and the engine load on the boost pressure, Figure 5 is a graph showing the output and NO _X generation amount relationship between the engine load on the boost pressure, and FIG. 6 is a graph showing an example of a boost pressure map showing the optimum supercharging pressure for the engine load and the engine speed.

The engine equipped with the turbocharger has a turbocharger 5 driven by the exhaust energy of the engine. An engine equipped with this turbocharger includes a cylinder block 2, a cylinder head fixed to the cylinder block 2, a cylinder 20 formed in the cylinder block 2, a piston 19 reciprocating in the cylinder 20, and a cylinder (not shown). It has a fuel injection nozzle and the like arranged on the cylinder head 1. An exhaust port 11 and an intake port (not shown) are formed in the cylinder head 1, and an exhaust valve 9 is arranged in the exhaust port 11, and an intake valve (not shown) is arranged in the intake port. An exhaust port 11 formed in the cylinder head 1 is connected to an exhaust manifold 3 serving as an exhaust passage via a manifold gasket or the like.

In the engine equipped with the turbocharger, the exhaust manifold 3 communicates with the turbine scroll 12 of the turbine 14 of the turbocharger 5 through the exhaust passage 4. The turbocharger 5 uses a turbocharger provided with a rotating electric machine, and is provided with a turbine 14 into which exhaust gas of an engine is fed, a shaft 16 having the turbine 14 fixed to one end, a compressor 15 attached to the other end of the shaft 16 and a shaft 16. And a generator / motor 17 which is a rotating electric machine attached to the motor. Although not shown, an exhaust gas processing device, a silencer, and the like, and in some cases, an energy recovery turbine can be provided downstream of the exhaust passage 13 on the outlet side of the turbocharger 5.

The controller 10 includes an operating state of the engine, that is, a boost pressure or a boost pressure detected by the boost pressure sensor 8, an engine load detected by the load sensor 7, and an engine rotation detected by the rotation sensor 6. Each detection signal of the number, that is, the engine speed is input. The supercharging pressure by the supercharging pressure sensor 8 may detect the supply pressure of the air supply system, the engine load by the load sensor 7 may detect the fuel supply amount or the depression amount of the accelerator pedal, and the rotation sensor 6 The engine speed can be determined by detecting the number of revolutions of the crankshaft 18. The controller 10 responds to these detection signals, and
Is operated as a generator, and the amount of power generated by the generator is controlled to control the supercharging pressure according to the boost pressure map. The control of the power generation amount of the power generation / motor 17 can be controlled by the power consumption of the power generated by the power generation / motor 17. For example, the amount of power generation can be increased by increasing the operation of the compressor 15 or consuming a large amount of electric power by auxiliary equipment, and the like. And reducing the power consumption of auxiliary equipment.

An embodiment of the operation of the engine having the turbocharger will be described with reference to a processing flowchart shown in FIG. FIG. 6 is a graph showing an example of a boost pressure map showing the optimum boost pressure with respect to the engine load and the engine speed. In the engine equipped with this turbocharger, the engine speed N is detected by the rotation sensor 6,
The engine load L is detected by the load sensor 7 (Step 30). As shown in FIG. 6, reads out the target supercharging pressure P ₁ according to the boost pressure map which is previously set corresponding to the engine speed N and engine load L (step 31),
Detecting the actual boost pressure P ₂ in supercharging pressure sensor 8 (step 32). Then, the target supercharging pressure P ₁ is compared with the actual supercharging pressure P _2, the actual boost pressure P ₂ is larger than the target supercharging pressure P ₁ (P ₂
> P ₁ ) or not large (P ₂ ≦ P ₁ ) (step 33).

[0018] In step 33, when the actual supercharging pressure P ₂ is larger than the target supercharging pressure P _1, as the actual boost pressure P ₂ becomes the target supercharging pressure P _1, the controller 10 turbocharger 5 Is controlled to operate the power generation / motor 17 of this embodiment as a power generator (step 34). When the generator / motor 17 of the turbocharger 5 operates as a generator to increase the amount of power generation, the operation of the compressor 15 decreases,
The supply air supplied from the compressor 15 to the engine is reduced, and the supercharging pressure is reduced (step 35). Therefore,
Target boost pressure P ₁ is greater than the actual boost pressure P ₂ is reduced, driving the actual boost pressure P ₂ becomes closer to the target boost pressure P _1, with reduced NO _X without reducing the engine output It can be performed.

In step 33, the actual supercharging pressure P
If ₂ is not greater than the target supercharging pressure P _1, as the actual boost pressure P ₂ becomes the target supercharging pressure P _1, the controller 10
The generator / motor 17 is operated as a generator to reduce the amount of power generation (step 36), and the turbocharger 5 is accelerated to increase the operation of the compressor 15. That is,
By sending the exhaust gas to the turbine 14 of the turbocharger 5, the operating state of the turbocharger 5 is strengthened, the supply air supplied from the compressor 15 to the engine increases, the supercharging pressure increases, and approaches the optimal supercharging pressure ( Step 37). Therefore, the target supercharging pressure P ₁ is smaller than the actual boost pressure P ₂ is increased, the actual boost pressure P ₂ becomes closer to the target boost pressure P _1, without reducing the engine output NO
Drive with reduced _X can be performed.

The engine provided with the turbocharger is operated as described above. As shown in FIG. 5, the controller 10 causes the generator / motor 17 as a rotating electric machine to operate as a generator according to the engine load L as shown in FIG. It is preferable to control as follows. For example, when the engine load L is low and the load L _L , the generator / motor 17 is operated as a generator so that the supercharging pressure becomes 300 mmHg, and the power generation of the generator is controlled. Also, sometimes the supercharging pressure medium load L _M controls the amount of power generated by the motor-generator 17 so as to 400 mmHg, further high load L _H sometimes supercharging pressure 500m
The power generation amount of the power generation / motor 17 is controlled so as to be mHg. Thereby, without reducing most of the engine output P over the entire operating range, the amount of the NO _X is controlled at low load L _L, the entire area of the medium load L _M and a heavy load L _H, the amount of the NO _X Will be reduced over the entire operating range.

The engine equipped with the turbocharger, which is configured as described above, such that the actual supercharge pressure P ₁ is optimum supercharging pressure P _3, and operate the motor-generator 17 as a generator , and controls the power generation amount of the generator, the engine can be driven in the state with reduced NO _X. Low load L _L in all operating regions of the engine, a middle load L _M
And continuously without the much reduce the engine output P without distinguishing at high load L _H, it is possible to operate the engine in boost pressure to reduce NO _X generation amount. Therefore, in the entire operating range of the engine, without hardly reducing the engine output P, it can be greatly reduced generation of NO _X.

As described above, an engine equipped with this turbocharger generates and generates electric power according to the operating state of the engine.
And controls the amount of power generated by the motor 17, as shown in FIG. 3, as compared to an engine having a conventional turbocharger without hardly reducing the engine output P, NO _X
Can be greatly reduced. That is, FIG.
Takes the engine load L is plotted on the horizontal axis, and taking the generation amount of the engine output P and NO _X on the vertical axis. Engine with a turbocharger, the engine output P becomes as shown by the dotted line E, also, the amount of the NO _X becomes as indicated by a dotted line F. In contrast, the engine having a conventional turbocharger, the engine output P becomes as shown by a solid line G, also, the amount of the NO _X becomes as shown by the solid line H.

[0023]

The engine provided with the turbocharger according to the present invention is constructed as described above.
It is possible to control the supercharging pressure to an optimal level for suppressing the generation amount of _X , and it is possible to reduce the generation amount of NO _X while maintaining the output. In particular, this engine is controlled so as hardly to reduce the engine output, continuously optimum supercharging pressure that can reduce the generation amount of the NO _X can be controlled, for example, at the time of low load to reduce the power generation by the rotary electric machine It was carried out, also at the time of high load to a control to increase the power generation amount of the rotating electrical machine, to reduce the generation of the NO _X while maintaining the engine output.

The controller sets a target boost pressure according to a preset boost pressure map corresponding to an engine speed and an engine load, and calculates the target boost pressure and the actual boost pressure detected by the sensor. comparison, since the actual supercharging pressure control amount of power generation of the rotating electric machine such that the target supercharging pressure, so as hardly to reduce the engine output, the optimum supercharging capable of reducing the generation amount of the nO _X The detection signal can be fed back to the pressure to control stepwise. For example, when the load is low, control is performed to reduce the power generation of the rotating electric machine, and when the load is high, control is performed to increase the power generation of the rotary electric machine, N with engine output maintained
It can reduce the generation amount of O _X.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of an engine provided with a turbocharger according to the present invention.

FIG. 2 is a processing flowchart showing one embodiment of the operation of the engine having the turbocharger according to the present invention.

FIG. 3 shows NO _X corresponding to the engine load of an engine equipped with a turbocharger according to the present invention and a conventional engine.
6 is a graph showing the relationship between the amount of generation and the output.

FIG. 4 is a graph showing a relationship between an engine speed and an engine load with respect to a supercharging pressure.

FIG. 5 shows engine load, output and NO _X with respect to boost pressure.
It is a graph which shows the relationship of the amount of generation.

FIG. 6 is a graph showing an example of a boost pressure map showing an optimum boost pressure with respect to an engine load and an engine speed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Cylinder block 3 Exhaust manifold 4 Exhaust passage 5 Turbocharger 6 Engine speed sensor 7 Engine load sensor 8 Supercharging pressure sensor 10 Controller 11 Exhaust port 13 Outlet exhaust passage 14 Turbine

Claims (2)

(57) [Claims] An exhaust manifold communicating with an exhaust port formed in a cylinder head, a turbocharger having a rotating electric machine communicating with the exhaust manifold through an exhaust passage, a sensor for detecting an operating state of an engine, and a detection signal of the sensor. A controller that operates in response to the rotating electric machine as a generator, controls a power generation amount of the rotating electric machine in accordance with an operation state of an engine, and controls a supercharging pressure ,
The controller follows the preset boost pressure map.
Optimum supercharging according to engine speed and engine load
Controlling the amount of power generated by the rotating electric machine so that
Et consisting engine with a turbocharger. 2. An exhaust port formed in a cylinder head.
An exhaust manifold that communicates with the exhaust manifold;
Turbocharger with rotating electric machine communicating through
Sensor for detecting operating state of engine, and the sensor
The rotating electric machine operates as a generator in response to the detection signal of
And the amount of power generated by the rotating electric machine depends on the operating state of the engine.
And a controller for controlling the supercharging pressure by setting the target supercharging pressure in accordance with a preset boost pressure map corresponding to the engine speed and the engine load. comparing the detected actual supercharging pressure, since the actual boost pressure is controlled power generation by the rotary electric machine such that the target boost pressure
Engine with a turbocharger comprising.