JP3134636B2 - Engine with positive displacement turbocharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine equipped with a positive displacement supercharger, which is provided with a positive displacement supercharger in an intake system and has a power recovery mechanism driven by receiving the energy of exhaust gas from the engine.

[0002]

2. Description of the Related Art In order to improve the operation performance of a gasoline engine or a diesel engine, it is necessary to increase the output. At that time, simply increasing the displacement will cause a decrease in fuel efficiency. Therefore, in order to improve the driving performance without changing the displacement, it is effective to provide a turbocharger or a positive displacement turbocharger in the intake system to increase the output of the engine.
However, these turbochargers are effective in terms of increasing output, but in the case of positive displacement turbochargers, they consume a part of the engine output,
In the case of a turbocharger, the exhaust resistance is increased, resulting in an output loss at this point. By the way, there is known an engine provided with a power recovery mechanism capable of recovering the exhaust gas energy of the engine to improve the engine output. For example, JP-A-3-
Japanese Patent Application Publication No. 117626 discloses a technique in which an exhaust turbine is linked with a supercharger via a belt, and the supercharger compresses intake air to perform supercharging, thereby improving the output of the engine.

Further, the turbo compound engine 1 shown in FIG. 22 is provided with a positive displacement supercharger 4 in the middle of an intake pipe 11, and a check valve 12 is provided in a bypass 111 which bypasses the supercharger. The torque of the crankshaft 2 of the engine 1 is transmitted to the positive displacement supercharger 4 via the pulley 3 and the electromagnetic clutch 16, and the supercharger compresses intake air to perform supercharging, thereby improving output. In particular, the exhaust turbine 5 is provided in the middle of the exhaust pipe 10, and the rotational force of the output shaft 15 of the turbine is transmitted to the gears on the crankshaft 2 via the first transmission 9, the fluid coupling 8 and the second transmission 7. 14 to recover exhaust gas energy to improve engine output. In order to maintain good power recovery efficiency of an engine equipped with such a power recovery mechanism, the ratio U / Co of the peripheral speed U of the rotor of the exhaust turbine 5 for power recovery to the exhaust gas flow rate Co of the turbine nozzle portion is required.
Must be maintained at a ratio corresponding to that the turbine efficiency η is maintained at the maximum value. That is, in the case of the turbo compound engine 1 shown in FIG. 22, as shown in FIG.
When the / Co value is 1, the peripheral speed U of the rotor and the exhaust gas flow rate Co at the turbine nozzle portion match, the turbine efficiency η becomes zero, and the turbine efficiency η reaches the maximum value near U / Co = 0.65. Is known to be.

[0004]

By the way, in the engine 1 with the positive displacement supercharger, the fluctuation of the exhaust gas flow velocity Co approximates the fluctuation of the engine speed, and the U / Co value becomes almost constant. As shown in the figure, the exhaust gas flow rate Co fluctuates greatly with respect to the load factor, and the U / Co value becomes the rated value 1
(U / Co (= 0.6 at which the turbine efficiency η becomes the maximum value)
5) or a value in the vicinity thereof). For this reason, there is a problem that U / Co cannot be kept constant at the rated value 1 and high turbine efficiency η cannot be obtained in a wide operating range. An object of the present invention is to provide a positive displacement supercharged engine capable of obtaining high turbine efficiency in a wide operating range.

[0005]

In order to achieve the above-mentioned object, an invention according to claim 1 is directed to a positive displacement supercharger provided in an intake passage of an engine, and a positive displacement supercharger provided between the positive displacement supercharger and the engine. A continuously variable transmission interposed between the engine and a crankshaft; a power recovery mechanism including an exhaust turbine provided in an exhaust passage of the engine; and a gear ratio of the continuously variable transmission according to an operation state of the engine. And a controller for controlling the stepless transmission, so that the exhaust turbine is connected to the positive displacement supercharger and the exhaust turbine is connected to the crankshaft via the continuously variable transmission. The exhaust turbine is connected to the positive displacement supercharger. According to a second aspect of the present invention, in the engine with the positive displacement supercharger according to the first aspect, the control unit sets a speed ratio of the continuously variable transmission in a high load region of the engine to a speed ratio of a supercharge control main body. And controlling the speed ratio of the continuously variable transmission in the low load range of the engine to be the speed ratio of the power recovery control main body in the low load range of the engine.
According to a third aspect of the present invention, in the engine with the positive displacement supercharger according to the first aspect, the engine includes a clutch for disconnecting the exhaust turbine and the continuously variable transmission from the positive displacement supercharger, The control unit controls the speed ratio of the continuously variable transmission so as to reduce the horsepower consumed by the positive displacement supercharger when the clutch is switched on and off. According to a fourth aspect of the present invention, in the engine with the positive displacement supercharger according to the first aspect, the engine includes a clutch for disconnecting the exhaust turbine and the continuously variable transmission from the positive displacement supercharger, The control unit controls a speed ratio of the continuously variable transmission such that turbine efficiency of the exhaust turbine is increased so that power can be recovered when the clutch is off.

[0006]

According to the first aspect of the present invention, a continuously variable transmission is interposed between the positive displacement supercharger and the crankshaft of the engine, and the continuously variable transmission is interposed between the continuously variable transmission and the positive displacement supercharger. By connecting an exhaust turbine, the exhaust turbine is configured to be connected to the crankshaft via the positive displacement supercharger and the continuously variable transmission, respectively, so that the speed ratio of a single continuously variable transmission is reduced. By controlling by the control unit, switching connection control of both the positive displacement supercharger and the power recovery turbine can be easily performed. In the invention according to claim 2, the control unit controls the speed ratio of the continuously variable transmission to be a speed ratio mainly controlled by the supercharging control in a high load range, and controls the positive displacement supercharger at a relatively high rotational speed. By controlling the speed ratio of the continuously variable transmission to be the speed ratio of the power recovery control main body in the low load range by power supply driving, power recovery control by the power recovery turbine can be performed. According to the third aspect of the present invention, the connection of the exhaust turbine and the continuously variable transmission to the positive displacement turbocharger can be cut off by the clutch, and the control unit switches the clutch on / off when the horsepower consumed by the positive displacement turbocharger is changed. Of the continuously variable transmission can be controlled so as to reduce the transmission speed. According to the invention of claim 4, the connection between the exhaust turbine and the continuously variable transmission with the positive displacement supercharger can be cut off by the clutch, and the control unit recovers power when the clutch is turned off. The speed ratio of the continuously variable transmission can be controlled so that the turbine efficiency of the continuously variable transmission is increased.

[0007]

FIG. 1 shows an engine with a positive displacement supercharger as an embodiment of the present invention. The engine 20 with a positive displacement supercharger is an in-line 6-cylinder, 4-valve engine, and operates in conjunction with an intake / exhaust system equipped with a positive displacement supercharger 24 and an exhaust turbine 32 to be described later. The system is configured to generate an output from the crankshaft 22 when the system is driven. The engine 20 with a positive displacement supercharger has a 6
A main body 201 having three cylinders 36 is provided with an intake manifold 35
The exhaust manifold 34 is connected to the intake manifold 35, and the intake passage 21 upstream of the intake manifold 35 is connected in parallel with a positive displacement supercharger 24 and a bypass passage 25 bypassing the supercharger and having a check valve 23. And their upstream portions are joined and communicated with an air cleaner (not shown). On the other hand, downstream of the exhaust manifold 34, an exhaust turbine 32 forming a power recovery mechanism is provided.
And a downstream port of the exhaust turbine 32 is opened to the outside air via a muffler (not shown).

The positive displacement supercharger 24 outputs the rotational force of the rotating shaft 33 of the exhaust turbine 32 from an output gear 39 provided adjacent to the flywheel 37 so as to introduce the torque.
, A fluid coupling 29 that absorbs torsional fluctuations and transfers torque, and a torque between the fluid joint 29 and the drive shaft 40 of the positive displacement supercharger 24. And a continuously variable transmission 28 that can perform transmission and reception of the transmission continuously.
Further, a gear 401 is integrally attached to the drive shaft 40 of the positive displacement supercharger 24, and the output shaft 33 of the exhaust turbine 32 is connected to the gear 401 via the first transmission 31. Here, the first transmission 31 constantly connects the rotation speed of the exhaust turbine 32 and the rotation speed of the positive displacement supercharger 24 while maintaining a constant reduction ratio, and is necessary for the exhaust turbine 32 to operate as a power recovery mechanism. Speed range and positive displacement turbocharger 24
The appropriate reduction ratio is set based on the speed range in which the necessary boost pressure can be secured during full load operation.

The check valve 23 on the bypass passage 25 provided in parallel with the positive displacement supercharger 24 has a center axis eccentric from the center of the cross section of the flow passage. For this reason, this valve element has a portion having a relatively large pressure receiving surface with respect to the central axis in the valve body.
Upon receiving a high pressure of air that is about to flow back through 5, the bypass 25 can be actuated to close and automatically closed to prevent flow. An intercooler 38 is provided at a front position of the engine 20 in the intake passage 26,
The intercooler 38 adopts a known configuration in which the pressurized air from the positive displacement supercharger 24 is air-cooled and sent to the cylinder 36 side. The continuously variable transmission (CVT) 28 is a primary pulley 28
1 and the secondary pulley 282
3 is interposed, the rotation transmitting position of the rotation transmitting roller 283 with both pulleys is switched by the action of the actuator 285, and the stepless speed change is performed by changing the diameter ratio at the rotational transmitting position with both pulleys. take. The continuously variable transmission (C
The actuator 285 of the (VT) 28 is controlled by the controller 50 via an electromagnetic valve (not shown) for switching the actuator.

The main part of the controller 50 is a microcomputer, and R is connected to each other by a bidirectional bus.
A well-known hardware configuration including an OM (read-on memory), a RAM (random access memory), a CPU (microprocessor), an input port, and an output port is employed. A rotation speed sensor 5 for outputting a rotation speed Ne signal of the engine as an operation state detecting means is provided at the input port here.
1. Load sensor 5 that outputs an engine load Acc signal
2. An output shaft speed sensor 53 that outputs the speed Ns of the output shaft 284 of the continuously variable transmission 28, and a supercharger speed sensor 54 that outputs the supercharger speed Np of the drive shaft 40 on the supercharger side. Etc. are respectively connected. On the other hand, an actuator 285 is connected to the output port via a corresponding drive circuit (not shown). The control program shown in FIG. 8 and the judgment values Acco in the high and low load regions shown in FIGS.
The maps m0, m1, m2, etc., which set the turbocharger rotation speed Npo corresponding to the target gear ratio under high load and low load, are stored and processed.

The controller 50 particularly has the following functions. That is, in the high load operation region (see the supercharging region in FIG. 6), the engine load Acc and the output shaft rotation speed Ns capable of achieving the target speed ratio are provided along the map m1 shown in FIG. The target turbocharger rotation speed Npo is calculated, and the actual turbocharger rotation speed Np is added to the target turbocharger rotation speed Npo.
The continuously variable transmission 28 is controlled to be switched so that Further, in the low-load operation range lower than the low-load threshold value (a value set in accordance with the engine speed), the target speed ratio is achieved along the map m2 shown in FIG. A target supercharger rotation speed Npo corresponding to the possible output shaft rotation speed Ns is calculated, and the continuously variable transmission 28 is switched and controlled in order to match the actual supercharger rotation speed Np to the target supercharger rotation speed Npo. Map m0 shown in Figure 2, it is created on the basis of the characteristic diagram of FIG. 12. The map m1 shown in FIG.
Created on the basis of the characteristic diagram of the supercharging zone, wherein, as the engine load Acc decreases, the target supercharger rotational speed Npo is the control value for the output shaft rotational speed Ns is set to decrease.

A map m2 shown in FIG. 4 is a non-supercharged region shown in FIG.
Is created based on the characteristic diagram of FIG. In this low-load operation range, as shown in FIG.
From [= Lta × {1- ( Npo / Npoa- 1) ² }], power consumption Ls at the time of idling of positive displacement supercharger 24 [= Lsa
× ( Npo / Npoa ) ³ ] in the range of 1 > Npo / Npoa > 0 so that the value Lt−Ls obtained by subtracting the maximum value Lmax (the value shown at the point p) at each Ns (= Ne / β). Control values are defined. Here, the subscript a indicates each value of the turbine efficiency maximum state (rated value 1) .

The control of the controller 50 is shown in FIG.
The CVT control routine will now be described. By turning on a main switch (not shown), the controller 50 executes a well-known main routine (not shown) including fuel injection control, ignition control, and the like, and reaches a CVT control routine shown in FIG. Here, the controller 50 may use the engine speed Ne or the output shaft speed Ns [= Ne × β (gear ratio of the second transmission 30)] and the engine load Acc (instead of this, the lever opening Rw, etc.). Can be detected). In steps a2 and a3, a high load determination value Acco corresponding to the current engine speed Ne is obtained from the map m0, and it is determined whether or not the current load Acc is larger than this value. If it is larger, the process proceeds to step a4 where Acco-α (hysteresis width)
If it is less than, it proceeds to steps a5 and a6, otherwise proceeds to step a7.

In step a4, the output shaft speed Ns and the target turbocharger speed Npo corresponding to the engine load Acc are obtained from the high load map m1 (FIG. 3) because the load is high. As a result, the target supercharger rotation speed Npo corresponding to the output shaft rotation speed Ns is obtained from the low load map m2 (FIG. 4), and the process proceeds to step a7. Here, a correction value that eliminates the deviation between the current supercharger rotation speed Np and the target supercharger rotation speed Npo is added to the current output, and the actuator of the continuously variable transmission (CVT) 28 is updated with the updated output. 285 is driven to make a correction. As a result, when the engine is in a high load range, the continuously variable transmission 28 is maintained at the gear ratio mainly controlled by the supercharging control along the map m1, and the displacement type supercharger 24 is maintained.
In the low load range, the continuously variable transmission 28 is held at the gear ratio mainly controlled by the power recovery control, and the power recovery amount of the exhaust turbine 32 is Lt-Ls. Can always be controlled to the maximum value Lmax (see line p in FIG. 7).

FIG. 9 shows another embodiment of the present invention. The engine 20a with a positive displacement supercharger here differs from the engine 20 in FIG. 1 except that a positive displacement supercharger 24a described later is equipped with an electromagnetic clutch 27 and that the control of the controller 50a is different. Many parts have the same configuration. Here, the same members are denoted by the same reference numerals, and the description thereof will not be repeated.
Here, rotational force is input to the positive displacement supercharger 24a of the engine 20a from the drive shaft 40 side via the electromagnetic clutch 27. The electromagnetic clutch 27 is connected to an output port of the controller 50a via a drive circuit 55 for performing on / off switching.

The controller 50a has the same hardware configuration as that of the controller 50 shown in FIG. 1. The ROM and the RAM have control programs shown in FIG. 19 and a determination value Acco of the high / low load range of the electromagnetic clutch 27 shown in FIGS. A map m3 (FIG. 17) and a map m4 (FIG. 18) for setting a target supercharger rotation speed Npo corresponding to the output shaft rotation speed Ns for achieving each target gear ratio in the entire range of the clutch and the on / off state are stored. . Map m3 shown in FIG. 17 is created based on the characteristic diagram of FIG. Here, a region where the engine torque is reduced from the full load torque to To (this value is set according to the engine speed) is set as a supercharging region, the electromagnetic clutch 27 is kept on, and the torque below the To is set. In the range, the electromagnetic clutch 27 is set to be kept off. Here, the engine load Acc corresponding to To
At o, the supercharging pressure was set to show 1 kg / cm ² . Further, the map m4 shown in FIG. 18 is created based on the characteristic diagrams of FIG. 14, FIG. 10, and FIG. FIG.
In the on-range of the electromagnetic clutch 27, which is a supercharging region, as the engine load Acc corresponding to the engine torque decreases, the control value, ie, the target supercharger rotation speed Npo (line i)
Is set to decrease.

On the other hand, as shown by the line a in FIG. 10, in the off range of the electromagnetic clutch 27, in order to perform control mainly of power recovery, that is, the rated value of U / Co becomes 1 (maximum turbine efficiency). Set the control value as follows. That is, as shown by the line m in FIG.
As the cc decreases, the rotation speed No of the exhaust turbine 32
(= Npo / γ (gear ratio of the first transmission 31)). Thereby, as shown in FIG. 10, the rated value of U / Co is set to 1 (maximum turbine efficiency). In the map m4 of FIG.
o was corrected by γ (the gear ratio of the first transmission 31), and the control value was unified to the target supercharger rotation speed Npo. With the setting of the control value Npo, as the engine load Acc corresponding to the engine torque decreases in the ON range of the electromagnetic clutch 27, the supercharger consumption horsepower decreases relatively greatly as shown in FIG. Shock at the time of turning on / off the electromagnetic clutch 27 can be reduced. Further, in the off range of the electromagnetic clutch 27, as shown in FIG. 15, the fuel consumption (see line k) of the engine 20a is reduced from the conventional value (see line l), and deterioration of fuel consumption can be prevented. 10 and 11 show the characteristics of the conventional device without the continuously variable transmission 28 (see the engine 1 in FIG. 22), and the change in U / Co and the recovery horsepower were low. It is obvious. 13 to 16, reference characters h, j, l, and n indicate characteristics of a conventional device without CVT control (see the engine 1 in FIG. 22). It is clear that the turbocharger rotation speed Np suddenly changed, and that the shock was large and that the fuel economy had deteriorated.

The control of the controller 50a will be described with reference to a CVT control routine shown in FIG. The controller 50 is turned on by turning on a main switch (not shown).
a executes a well-known main routine (not shown) including fuel injection control, ignition control, and the like, and reaches the CVT control routine in FIG. Here, the controller 50a determines whether the engine speed Ne or the output shaft speed Ns [= Ne /
β (gear ratio of second transmission 30)] and engine load Acc
(The lever opening Rw or the like can be used instead.) In steps s2 and s3, the judgment load Acco at the current engine speed Ne is obtained from the map m3.
It is determined whether the current load Acc is larger than this value. If it is larger, the process proceeds to step s4. If it is smaller than Acco-α (hysteresis width), the process proceeds to steps s5 and s6. Otherwise, the process proceeds to steps s5 and s7. move on.

In step s4, the electromagnetic clutch 27 is turned on in the supercharging range, and in step s6, the electromagnetic clutch 27 is turned off, and the process proceeds to steps s7 and s8. Here, the current output shaft rotational speed Ns [= Ne along the map m4 (FIG. 18).
/ Β (gear ratio of second transmission 30)] and engine load A
Target turbocharger rotation speed Np that can achieve speed ratio according to cc
o, the current turbocharger rotation speed Np and the target turbocharger rotation speed Np
Add a correction value to eliminate the deviation of o to the current output,
With the updated output, the actuator 285 of the continuously variable transmission (CVT) 28 is driven to perform correction. in this way,
Target turbocharger rotation speed Npo corresponding to the speed ratio of continuously variable transmission 28
In the setting of Npo, Npo is set so that the supercharger is mainly controlled in the on range of the electromagnetic clutch 27 so as to improve the output, and Npo is set in the on / off switching range of the electromagnetic clutch 27 so as to reduce the superpower consumption horsepower. Is set, the U / Co value of the exhaust turbine 32 can be maintained at the rated value 1 (turbine efficiency approximates the maximum value) so that the shock can be reduced and the power recovery amount can be sufficiently achieved when the electromagnetic clutch 27 is off. By setting Npo as described above, fuel efficiency can be improved.

The controller 50a of the engine 20a with a positive displacement supercharger shown in FIG. 9 stores the control program shown in FIG. 19 in the ROM and RAM. Instead of the control program, the controller 50a shown in FIG. The control may be performed such that the target supercharger rotation speed Npo that can achieve the target gear ratio when the electromagnetic clutch 27 is off is set in a map m5 (see FIG. 20). A map m5 shown in FIG. 20 is a map in which set values of a portion that performs a control area mainly for power recovery when the electromagnetic clutch 27 is off are provided as separate maps from among the set values of the map m4 of FIG. Here, the set value of the map m4 is used only when the electromagnetic clutch 27 is turned on. The control of the controller 50a will be described according to the CVT control routine shown in FIG. Here, each control from step s1 to step s6 and step s8 is the same control processing as the control flow of FIG. 19, and a duplicate description will be omitted.

In the control program shown in FIG. 21, the electromagnetic clutch 27 is switched in steps s4, s5, and s6. When step s10 is reached, it is determined whether the electromagnetic clutch 27 is currently on or off. If the advance is off, the process proceeds to step s12. In step s11, the control value of the supercharger is calculated from the control value of the supercharger as the target supercharger rotational speed Npo according to the current output shaft rotational speed Ns and the engine load Acc. In step s12, the map m5 ( According to FIG. 20), the control value of the power recovery control main body is changed to the current output shaft rotation speed Ns [= Ne / β.
(Gear ratio of second transmission 30)] and engine load Acc
The target turbocharger rotation speed Npo according to the above is obtained. Moreover,
Proceeding to step s8, a correction value that eliminates the deviation between the current turbocharger rotation speed Np and the target supercharger rotation speed Npo is added to the current output, and the continuously variable transmission (CVT) 2 is updated with the updated output.
8 is driven to perform correction. In this case as well, the same control processing as in the case of using the control program shown in FIG. 19 can be performed. In particular, since the use maps in the on / off region of the electromagnetic clutch 27 are divided, the control processing with the electromagnetic clutch on and the control processing with the off Can be controlled to an appropriate value.

[0022]

As described above, according to the first aspect of the present invention, the control unit controls the speed ratio of the single continuously variable transmission in accordance with the operation state of the engine, so that the positive displacement supercharger is provided. In addition, the number of revolutions of the exhaust turbine of the power recovery mechanism can be controlled. In addition, by maintaining the ratio between the peripheral speed of the turbine rotor and the exhaust gas flow velocity of the nozzle portion at a substantially rated value, it is possible to maintain high exhaust energy recovery efficiency.
Further, in connecting the power recovery turbine and the positive displacement supercharger to the crankshaft, the continuously variable transmission is shared without being individually arranged, that is, there is no need to add an additional transmission and the engine becomes larger. And cost increase can be prevented. According to the second aspect of the present invention, in the high load range, the turbocharger can be driven by the supercharger at a relatively high rotation speed and the output can be increased efficiently in the high load range. In addition, the power recovery control can perform control for always maintaining the maximum amount of power recovery by the power recovery turbine. According to the third aspect of the present invention, when the clutch is switched on and off, the speed ratio of the continuously variable transmission is controlled so as to reduce the horsepower consumption of the positive displacement supercharger. Is reduced, so that the clutch switching shock can be reduced, and deterioration of fuel efficiency can be prevented. According to the invention of claim 4, since the speed ratio of the continuously variable transmission is controlled so that the turbine efficiency of the exhaust turbine is increased so that power is recovered when the clutch is off, the exhaust gas is exhausted when the clutch is switched off. Turbine efficiency of the turbine is increased, and power can be efficiently recovered.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an engine with a positive displacement supercharger according to the present invention.

FIG. 2 is a conceptual diagram of a load area map used by a controller of the engine of FIG. 1;

FIG. 3 is a conceptual diagram of a supercharger rotation speed map in a high load region used by a controller of the engine of FIG. 1;

FIG. 4 is a conceptual diagram of a supercharger rotation speed map in a low load range used by the engine controller of FIG. 1;

5 is a characteristic diagram of a supercharger rotation speed map in a high load region used by a controller of the engine shown in FIG. 1;

6 is a characteristic diagram of a high-low load region of the engine used by the engine controller of FIG. 1;

7 is a characteristic diagram of an output shaft rotation speed- (Lt-Ls) value used by a controller of the engine in FIG. 1 in a low load range.

FIG. 8 is a CVT used by the engine controller of FIG. 1;
It is a flowchart of a control routine.

FIG. 9 is an overall configuration diagram of an engine with a positive displacement supercharger as another embodiment of the present invention.

FIG. 10 is a diagram showing a relationship between a load factor and a rated value of U / Co used by a controller of the engine in FIG. 9;

FIG. 11 is a diagram showing a relationship between recovered horsepower and torque used by a controller of the engine in FIG. 9;

12 is a diagram showing a relationship between a torque and an engine speed used by a controller of the engine shown in FIG. 9;

FIG. 13 is a diagram showing a relationship between supercharger consumption horsepower and torque used by the controller of the engine in FIG. 9;

14 is a diagram showing a relationship between supercharger rotation speed and torque used by a controller of the engine in FIG. 9;

FIG. 15 is a diagram showing a relationship between fuel consumption and torque used by a controller of the engine in FIG. 9;

16 is a diagram showing a relationship between a recovered turbine speed and a torque used by a controller of the engine of FIG. 9;

FIG. 17 is a conceptual diagram of a load range map used by the engine controller of FIG. 9;

18 is a conceptual diagram of a supercharger rotation speed map over the entire on / off range of an electromagnetic clutch used by the engine controller of FIG. 9;

19 is a diagram illustrating a CV used by the controller of the engine shown in FIG. 9;
It is a flowchart of a T control routine.

20 is a conceptual diagram of a supercharger rotation speed map in an off range of another electromagnetic clutch used by the engine controller of FIG. 9;

FIG. 21 is a flowchart of another CVT control routine used by the engine controller of FIG. 9;

FIG. 22 is an overall configuration diagram of a conventional engine with a positive displacement supercharger.

FIG. 23 is a U / Co-load factor diagram performed by the engine of FIG. 22.

24 is a diagram showing turbine efficiency-U performed by the engine shown in FIG. 22.
It is a / Co characteristic diagram.

[Explanation of symbols]

 Reference Signs List 20 engine 20a engine 22 crankshaft 24 positive displacement supercharger 28 continuously variable transmission 32 power recovery mechanism

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02B 41/10 F02B 37/00 302 F02B 39/04 F02B 39/12

Claims (4)

(57) [Claims] 1. A positive displacement supercharger provided in an intake path of an engine, a continuously variable transmission interposed between the positive displacement supercharger and a crankshaft of the engine, and exhaust of the engine A power recovery mechanism including an exhaust turbine provided in a passage; and a control unit that controls a speed ratio of the continuously variable transmission in accordance with an operation state of the engine. Connecting the exhaust turbine between the continuously variable transmission and the positive displacement supercharger so as to connect the exhaust turbine to the crankshaft via the continuously variable transmission. Engine with positive displacement turbocharger. 2. The control unit controls the speed ratio of the continuously variable transmission to a speed ratio mainly controlled by a supercharger in a high load range of the engine, and controls the speed ratio of the engine in a low load range of the engine. 2. The engine with a positive displacement supercharger according to claim 1, wherein a speed ratio of the continuously variable transmission is controlled to be a speed ratio mainly of a power recovery control in a low load range. 3. The engine according to claim 1, wherein the engine includes a clutch that disconnects the exhaust turbine and the continuously variable transmission from the positive displacement supercharger, and the control unit controls the positive displacement supercharger when the clutch is switched on and off. 2. The engine with a positive displacement supercharger according to claim 1, wherein a speed ratio of the continuously variable transmission is controlled so as to reduce consumed horsepower. 4. The engine includes a clutch that disconnects the exhaust turbine and the continuously variable transmission from the positive displacement supercharger, and the control unit is configured to recover power when the clutch is turned off. The engine with a positive displacement supercharger according to claim 1, wherein a speed ratio of the continuously variable transmission is controlled so that a turbine efficiency of the exhaust turbine is increased.