JPH0693891A - Control device for plurality of engines - Google Patents

Abstract

PURPOSE:To provide a control device improved in engine brake performance at deceleration in a vehicle provided with a regularly operated main engine and a sub-engine connected to the main engine according to the operating area of the main engine. CONSTITUTION:In a low load area of a main engine a4A, a sub-engine 14B is separated from the main engine 14A by a sub-clutch 70B, and when the rotating speed of the main engine 14A is a determined rotating speed or more, and laid in extremely low load state, a control device 112 controls a clutch actuator 115 so that the sub-engine 14B is connected to the main engine 14A through the sub-clutch 70B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a plurality of engines, and in particular, it is applied to a vehicle equipped with two engines and adapted to travel by using one or both of the above engines according to the traveling situation. The present invention relates to a controller for a plurality of engines suitable for

[0002]

2. Description of the Related Art In a normal automobile, the maximum output is set to the output required in a normal driving condition, with a margin depending on the character of the automobile. The engine installed is also capable of generating its maximum output, and the displacement is almost determined by the maximum output.

By the way, the traveling load is constantly changing, and when the road surface is smooth and the inclination is small, the traveling load becomes small and the engine has a smaller displacement than the engine actually mounted. However, there are cases where you can drive sufficiently. Then, in a traveling state in which an engine with a small displacement is sufficient, it is preferable to reduce the displacement in terms of environmental pollution.

As a method of changing the displacement of the engine according to the running state, for example, in a multi-cylinder engine, a method of stopping the fuel supply to a specific cylinder or US Pat.
It is conceivable to use two engines, as disclosed in JP 361,059 and JP 62-147030.

[0005]

However, in the above conventional example, when the fuel supply to a specific cylinder is stopped in the former multi-cylinder engine, the movement of the piston in the cylinder whose fuel supply is stopped is stopped. Becomes a load resistance, which lowers the efficiency of the engine.

Further, when the latter two engines are used, when traveling using only one engine,
Since the other engine in the non-operating state can be excluded from the power system by a clutch or the like, the problem that the non-operating engine becomes the load resistance can be avoided,
Since each uses an engine with a relatively small displacement, there is a problem in that the effect of engine braking is poor during deceleration.

If one of the two engines is a main engine that is constantly operated and the other engine is a sub engine that is connected to the main engine according to the operating region of the main engine, If the engine is intermittently connected to the main engine, the drivability is deteriorated.

In view of the above-mentioned circumstances, the present invention provides a control device for a plurality of engines, which improves engine braking performance during deceleration and drivability during traveling, and also reduces environmental pollution. To aim.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to a control system for a plurality of engines in a vehicle having a main engine which is always operated and a sub engine which is connected to the main engine according to an operating region of the main engine. The invention described in claim 1 is such that the sub-engine is separated from the main engine in the low load region of the main engine, and when the main engine rotational speed is equal to or higher than a predetermined rotational speed and is in an extremely low load region. , And a control means for connecting the sub-engine to the main engine.

The invention as set forth in claim 2 further comprises control means for disconnecting the sub engine from the main engine in a low load region of the main engine and stopping the sub engine when the load of the main engine further decreases. It is characterized by

Further, the invention described in claim 3 is characterized in that it is provided with a control means for disconnecting the sub-engine when the sub-engine is cold.

Further, the invention according to claim 4 further comprises a control means for expanding an operating region of the main engine, in which the sub engine is separated from the main engine, when the sub engine is cold than when it is warm. It is characterized by

Further, according to the invention described in claims 5 to 7, the sub-engine is disconnected from the main engine in a low load region of the main engine, and the sub-engine is stopped when the load of the main engine further decreases. The first control mode and the second control mode in which the sub engine is only stopped by disconnecting the sub engine from the main engine in the low load region of the main engine, and the second control mode in which the sub engine is always connected to the main engine It is characterized by comprising selection means capable of selecting at least one control mode among the three control modes.

[0014]

According to the invention described in claim 1, when only the accelerator pedal, which was in the depressed state during traveling, is suddenly restored, the sub engine is connected to the main engine, so that the engine braking is performed. In addition to improving the performance, it is possible to reduce the frequency of shifting from the state in which the vehicle is running by both the main engine and the sub-engine to running only by the main engine, and there is an effect that drivability is improved accordingly.

According to the invention described in claim 2, the sub-engine is stopped in the extremely low load region of the main engine, so that the fuel efficiency can be improved.

According to the third and fourth aspects of the present invention, the sub-engine is disconnected from the main engine when the sub-engine is cold, or the operating range of the main engine in which the sub-engine is disconnected from the main engine. As the sub-engine is colder than it is warm, it is less likely to be connected to the main engine when the sub-engine is cold, and the unpurified exhaust gas is exhausted from the sub-engine accordingly. The risk of

Further, according to the invention described in claims 5 to 7, since the driver can select the traveling mode in which the driving is emphasized and the traveling mode in which the fuel consumption is emphasized, the degree of freedom in traveling can be increased. Has the effect of being enlarged.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a rear structure of an automobile to which a control system for a plurality of engines according to the present invention is applied, and FIG. 2 is a side view thereof. Also, FIG. 3 and FIG.
[Fig. 4] is a plan view and a side view showing an appearance of the power plant with the engine removed.

In FIGS. 1 and 2, the first and second engines 14A, 14A,
14B is mounted in parallel. These first and second engines 14A, 14B are arranged between the left and right rear wheels 15A, 15B, and a pair of seats 1 is provided in front of these engines 14A, 14B.
It is a four-wheel drive vehicle based on the so-called rear engine / rear drive (RR) configuration in which 6 and 16 are arranged.

The first and second engines 14A, 14B are each composed of a rotary engine having two rotors, and, as is particularly clear from FIG. 6, the respective output shafts 18A, 18B are arranged in the vehicle width direction. The output shafts 18A and 18B are mounted on the vehicle body 10 in an extended, so-called horizontal state, and the output shafts 18A and 18B are arranged with their axes 19 aligned with each other. The first and second engines 14A and 14B are integrally connected by the clutch housing 20 interposed therebetween.

In the case of the present embodiment, the first engine 14A mounted on the left side of the vehicle body 10 is a supercharged engine equipped with the turbocharger 22 and is a main engine which is always operated. Further, the second engine 14B mounted on the right side of the vehicle body 10 is a naturally aspirated (NA) engine which is a sub-engine which is operated only in a predetermined operation region of the first engine 14A and which is not equipped with a supercharging device. Has become.

A space for arranging engine accessories is formed above the clutch housing 20 connecting the two engines 14A and 14B, and in this embodiment, the space is provided in the first and second spaces. An air cleaner 28 and a fresh air duct 30 which are shared by the two engines 14A and 14B are provided. Therefore, as shown in FIGS. 3 and 4, a mounting seat 20a for mounting the air cleaner 28 is provided on the upper surface of the clutch housing 20.

The intake / exhaust system of both engines 14A and 14B will now be described with reference to FIG. 5 as well.
On top of A and 14B, the surge tanks 24A and 24A
B is fixed, and the surge tank 24A on the first engine 14A is communicated with the four intake ports of the first engine 14A via the intake manifold 26A having four intake passages inside, and the second Surge tank 14B on engine 14B
Are also communicated with the four intake ports of the second engine 14B via an intake manifold 26B which also has four intake passages inside.

A fresh air duct 30 is connected to the air cleaner 28 shared by both engines 14A and 14B, and an intake passage 35B of the first engine 14A is formed between the air cleaner 28 and the surge tank 24B of the second engine 14B. The intake pipe 32 is connected. Therefore, the fresh air sucked from the fresh air duct 30 is directly supplied to the surge tank 24B of the second engine (sub engine) 14B through the air cleaner 28 and the intake pipe 32.

An intake pipe 34 is connected between the air cleaner 28 and the compressor 22a of the turbocharger 22, and the fresh air sucked from the fresh air duct 30 passes through the air cleaner 28 and the intake pipe 34 to the above compressor.
Supplied to 22a. An intercooler 36 is mounted in front of the left rear wheel 15A of the vehicle body 10, and an intake pipe 38 is connected between the intercooler 36 and the compressor 22a. The fresh air that has been compressed by the compressor 22a and has reached a high temperature is supplied to the intercooler 36 through the intake pipe 38, where it is cooled, and then the intercooler is cooled.
It is designed to be supplied to the surge tank 24A through an intake pipe 40 connected between the 36 and the surge tank 24A of the first engine (main engine) 14A. And intake pipe 3
4, 38 and 40 by the intake passage 35 of the first engine 14A
A is formed.

On the other hand, the exhaust gas of the first engine 14A is exhausted from the engine 14A to the rear, and the exhaust manifold 42A.
Is supplied to the turbine 22b of the turbocharger 22, and drives the turbine 22b directly connected to the compressor 22a. Next, the exhaust is a case containing an exhaust purification catalyst.
It is supplied to 44 through an exhaust pipe 46 and purified. Further, the exhaust gas enters the silencer 50 through the exhaust pipe 48, and after the exhaust noise is reduced, the exhaust gas is exhausted to the outside from the exhaust pipe 52. Also,
The exhaust gas of the second engine 14B is supplied to the exhaust pipe 48 through an exhaust manifold 42B extending rearward from the engine 14B and joined to the exhaust gas of the first engine 14A.

Incidentally, engine accessories such as an alternator driven by an engine, an air conditioner compressor, an oil pump for power steering and the like are mounted at least on the side of the first engine 14A which is always operated, and in FIG. The air conditioner compressor and the power steering oil pump are designated by reference numerals 51 and 53, respectively.

At the rear side of the clutch housing 20 connecting the first and second engines 14A and 14B, as shown in FIG. 3, a transmission case 54 is integrally connected in a horizontal position. Further, a central differential device as shown in FIG. 6 (hereinafter abbreviated as "center differential")
56 and rear wheel differential (hereinafter referred to as "rear differential")
The 58 and the differential case 60 are connected to each other by being integrated, and the first and second engines 14A and 14B and the clutch housing 20 are connected.
And the differential case 60 are rigidly connected to each other to form an integral structure.

The structure of the power plant 62 will be described with reference to FIGS. 6 and 7.

A central rotary shaft 64 is provided between the output shafts 18A and 18B of the first and second engines 14A and 14B.
It is extended in a relationship in which the axes 19 of A and 18B are aligned. The central rotating shaft 64 is the output shaft of the first engine 14A.
An inner shaft 64a connected to 18A and a hollow outer shaft 64b coaxially and rotatably provided on the outer side of the inner shaft 64a.
And consists of.

More specifically, the inner shaft 64 of the central rotary shaft 64
The left end of a is spline-coupled to the center of a flywheel 66A fixed to the end of the output shaft 18A of the first engine 14A, and is configured to rotate integrally with the output shaft 18A of the first engine 14A. ing. The right end of the inner shaft 64a is the second
The flywheel 66B fixed to the end of the output shaft 18B of the engine 14B is rotatably supported by a bearing 68 at the center of the flywheel 66B so that the flywheel 66B can rotate separately from the output shaft 18B of the second engine 14B. It is configured.

The outer shaft 64b of the central rotary shaft 64 is the first engine.
Output shaft 18A of the first engine 14A via a main clutch 70A that includes a flywheel 66A of 14A as a part of its configuration.
The inner shaft 64a is connected to the output shaft 18B of the second engine 14B via a sub-clutch 70B having the flywheel 66B of the second engine 14B as a part of its configuration.

The main clutch 70A is a flywheel 66.
A, a clutch disk 72A provided to face the surface of the flywheel 66A, a pressure plate 74A for pressing the clutch disk 72A onto the surface of the flywheel 66A, and a diaphragm spring 76A. Is to have. The clutch disc 72A is splined to the outer periphery of the outer shaft 64b of the central rotary shaft 64.

Similarly, the sub-clutch 70B includes a flywheel 66B, a clutch disc 72B provided facing the surface of the flywheel 66B, and a clutch disc 72B.
It is equipped with a pressure plate 74B for pressing B on the surface of the flywheel 66B and a diaphragm spring 76B, the clutch disc 72B of which has a central rotary shaft.
The inner shaft 64a of 64 is splined to the outer circumference.

When the main clutch 70A is fastened, the spring force of the diaphragm spring 76A is applied to the pressure plate.
Acting on 74A, the pressure plate 74A presses the clutch disc 72A onto the flywheel 66A surface.

Further, the disengagement of the main clutch 70A is
Push rod provided at the tip of the hydraulic cylinder 78A
79A is performed by driving the release fork 80A in the direction of arrow A in FIG. That is, when the release fork 80A is driven in the direction of arrow A, the tip of the release fork 80A moves in the direction of arrow C to invert the diaphragm spring 76A to the position shown by the chain line, whereby the clutch disc 72A is moved. The pressing force of the pressure plate 74A against the pressure disappears, and the engagement of the main clutch 70A is released.

Similarly, the sub-clutch 70B is engaged by the spring force of the diaphragm spring 76B acting on the pressure plate 74B so that the pressure plate 74B presses the clutch disc 72B against the flywheel 66B surface.

The engagement of the sub-clutch 70B is released by pushing the push rod 79 provided at the tip of the hydraulic cylinder 78B.
B is performed by driving the release fork 80B in the direction of arrow B in FIG. That is, when the release fork 80B is driven in the direction of arrow B, the release fork
The tip portion of 80B moves in the direction of arrow D to invert the diaphragm spring 76B to the position shown by the chain line, whereby the pressing force of the pressure plate 74B against the clutch disc 72B disappears and the sub-clutch 70B is engaged. It will be canceled.

With the above configuration, when the sub-clutch 70B is engaged, the output shafts 18A, 18B of the first and second engines 14A, 14B are directly connected via the inner shaft 64a of the central rotary shaft 64, and the first And the outputs of the second engines 14A and 14B are collected.

When the sub-clutch 70B is released, the output shaft 18B of the second engine (sub-engine) 14B is released.
Are excluded from the drive train.

On the other hand, when the main clutch 70A is engaged, when the sub clutch 70B is not engaged, only the rotational force of the output shaft 18A of the first engine (main engine) 14A is outside the central rotational shaft 64. When the sub-clutch 70B is engaged, the collective force of the rotational forces of the output shafts 18A, 18B of the first and second engines 14A, 14B is transmitted to the shaft 64b, and the outer shaft 64b of the central rotational shaft 64. Be transmitted to.

Further, when the main clutch 70A is released, the output shafts of the first and second engines 14A and 14B are released.
18A and 18B are excluded from the power transmission system.

An output gear 82 is integrally formed in the central portion of the outer shaft 64b of the central rotating shaft 64, and the outer shaft 64b is a clutch via a pair of bearings 84, 84 on both sides of the output gear 82. It is rotatably supported by the housing 20. Further, an intermediate shaft 86 having an axis 85 parallel to the axis 19 of the central rotation shaft 64 is fixed to the clutch housing 20, and an intermediate gear 88 meshing with the output gear 82 is rotatably attached to the intermediate shaft 86. It is pivotally supported.

The transmission 90 housed in the transmission case 54 is provided with an input shaft 92 and an output shaft 94, each of which has axes 91 and 93 parallel to the axis 19 of the central rotary shaft 64. The intermediate gear 88 is connected to the input gear 96 integrally formed in the substantially central portion of the shaft 92.
Are in mesh. Therefore, the rotational force transmitted to the outer shaft 64b of the central rotating shaft 64 by the engagement of the main clutch 70A is transmitted to the transmission 90 via the output gear 82, the intermediate gear 88 and the input gear 96 in order.

Between the input shaft 92 and the output shaft 94 of the transmission 90, as is apparent from the skeleton diagram of FIG. 6, the speed-changing gear train (for first to fifth speeds and reverse) has a known structure. It is arranged. Then, when any one of the gears in the transmission gear train is selected to mesh with each other inside the transmission 90, the power of the first engine 14A input from the input shaft 92 or the first and second engines 14A. , 14B are transmitted to the output shaft 94 via the set of gears.

An output gear 98 is integrally formed at one end of the output shaft 94 of the transmission 90.
The power output from the 98 is transmitted to the center diff 56 via the ring gear 100 of the center diff 56, which itself is composed of a double pinion type planetary gear mechanism, and is divided into the rear wheel and the front wheel by the center diff 56. To be done. The driving force for the rear wheels is transmitted to the rear differential 58 via the carrier 101 of the planetary gear that constitutes the center differential 56. Rear differential
The left and right rear wheel drive shafts 102, 104 are coupled to the 58, and the rear wheel drive force is transmitted via the rear wheel drive shafts 102, 104 to the left and right rear wheels 15A,
It is transmitted to 15B.

The sun gear 103 of the center differential 56 is formed integrally with one end of a hollow shaft 105 coaxially and rotatably provided on the outer side of the left rear wheel drive shaft 102 for the front wheel. The driving force is transmitted to the shaft 10 via the sun gear 103.
5 Bevel gear fixed to the shaft 105.
Bevel gear 107 and propeller shaft 108 meshing with 106
Is transmitted to the front differential (not shown) via the. Then, the front differential is divided into left and right front wheel drive shafts and transmitted to the left and right front wheels.

Although not shown in FIG. 7, a lock mechanism for directly connecting the ring gear 100 of the center differential 56 and the carrier 101 to lock the center differential 56 is provided.

The above is the configuration of the power plant 62.
The power plant 62 is mounted on the vehicle body 10 via mounting members 110A, 110B, 110C provided at at least three places. That is, FIG. 1 and FIG.
As is apparent from the first mounting member 110 A
Is provided at the left front end of the first engine 14A, and the second mounting member 110B is provided at the right front end of the second engine 14B. The third mounting member 110C is provided at the rear of the transmission case 54. Further, when the fourth mounting member is provided, the third mounting member 110C and the third mounting member 110C are provided side by side at the rear of the transmission case 54.

Next, the control device of the power plant 62 configured as described above will be described with reference to the block diagram of FIG.

The control circuit 112 controls the outputs of the load sensor 114 and the engine speed sensor 116 provided in the first engine (main engine) 14A and the exhaust temperature sensor 118 provided in the second engine (sub engine) 14B. Based on both the output and the position of the manual switch 120 that allows the driver to select three control modes, the ignition device 122 of the second engine 14B is turned ON / OFF, and the sub-clutch 70B is controlled via the clutch actuator 115. Is configured.

The main clutch 70A is temporarily disengaged by the clutch pedal 75 when the transmission 90 shifts.

Next, the control routine executed by the control circuit 112 will be described with reference to the flowchart of FIG. 9 and the control maps A to C of FIG.

First, in step S1 of FIG.
Then, the ignition switches of the second engines 14A and 14B are turned on, and in step S2, starters (not shown) provided in the first and second engines 14A and 14B are driven to start both engines 14A and 14B. The sub-clutch 14B is in the OFF state at the time of starting.

In step S3, the manual switch 12
The contact position of 0 is checked, and when it is determined that the a contact of the manual switch 120 is selected, step S4
Proceeding to step S2, it is checked from the output of the exhaust temperature sensor 118 of the second engine 14B whether the exhaust temperature of the second engine 14B is equal to or higher than the set value. Then, when the exhaust temperature of the second engine 14B is less than the set value (when it is cold), the process proceeds to step S5, the sub clutch 70B is turned off, and the second engine 14B is not connected.

Next, in step S4, the second engine
When the exhaust temperature of 14B is above the set value (when warm)
In step S6, control is performed according to map A in FIG. That is, when the operating region of the first engine 14A is in the low load region I, the operation proceeds to step S5 to turn off the sub-clutch 70B, and when it is in the high load or high rotation region II, the operation proceeds to step S7 and the sub-clutch. 70B is engaged and the second engine 14B is connected to the first engine 14
Connect to A. When the operating range of the first engine 14A is in the extremely low load common sense III, the sub clutch 70B is turned off in step S8, and the second engine 14B is turned off.
The ignition device 122 is turned off to stop the second engine 14B.

Next, in step S3, when it is determined that the contact position of the manual switch 120 is the b contact, the exhaust temperature of the second engine 14B is checked in step S10, and when the second engine 14B is warm, In step S11, control is performed according to map B in FIG.

In this case, when the operating region of the first engine 14A is in the low load region IV, the routine proceeds to step S12,
With the sub-clutch 70B in the OFF state, the second engine 14B
Does not connect. In other operating areas V, step S7
To the second engine 14
Connect B.

Particularly in this map B, the first engine 14A
Even if the operating region of is the extremely low load region, when the engine speed is equal to or higher than the predetermined speed N ₁ , the sub clutch 70B is turned on.
Then, the second engine 70B is connected.

Furthermore, the operating range of the first engine 14A is
From the point P ₁ on the clutch ON area V on the map B,
Clutch OFF range without changing engine speed
In the case where there is a sharp change again to point P ₂ on the extremely low load region (clutch ON region) after passing IV, if this change is made within a predetermined time, the sub clutch 70B is prohibited from turning OFF. In order to do so, a delay timer is provided.

By performing such control, the engine braking performance is improved and the sub clutch
70B is turned off less frequently,
This has the effect of improving drivability.

On the other hand, when it is determined in step S10 that the exhaust temperature of the second engine 14B is lower than the predetermined temperature, the process proceeds to step S13 and control is performed according to the map C in FIG.

In this map C, the area IV where the sub clutch 70B is turned off in step S12 is the other maps A and B.
It is enlarged, and the process proceeds to step S14 to turn on the sub-clutch 70B only when the region is outside the region IV.

Finally, in step S3, when it is determined that the contact position of the manual switch 120 is the c contact, the process proceeds to step S14, the sub clutch 70B is always engaged, that is, the second engine 70B is always The connected driving mode is selected.

By performing such control, the engine braking performance, drivability, fuel efficiency performance, and emission performance can all be improved, and the vehicle can travel according to the driver's will.

In the above-described embodiment, the first engine (main engine) 14A which is always operated is a supercharged engine and is temporarily operated depending on the situation, and its output is added to the main engine. Although the second engine (sub engine) 14B is a naturally aspirated engine, the first engine 14A may be a naturally aspirated engine and the second engine 14B may be a supercharged engine. Furthermore, both engines 14A, 14
A combination in which both B are naturally aspirated engines or both engines 14A and 14B are both supercharged engines are also conceivable.

[Brief description of drawings]

FIG. 1 is a plan view showing a vehicle body rear structure to which the present invention is applied.

FIG. 2 is a side view of the same.

FIG. 3 is a plan view showing the appearance of the power plant with the engine removed.

FIG. 4 is a side view of the same.

FIG. 5 is a schematic diagram showing the structure of an intake / exhaust system.

FIG. 6 is a skeleton diagram showing the configuration of the power plant.

FIG. 7 is a sectional view showing a detailed configuration of a clutch portion.

FIG. 8 is a block diagram showing a control device.

FIG. 9 is a flowchart showing a control routine.

FIG. 10 is a control map provided in the control circuit.

[Explanation of symbols]

 10 Body 14A 1st engine 14B 2nd engine 15A, 15B Rear wheels 18A, 18B Engine output shaft 20 Clutch housing 22, 126, 128 Turbocharger 24A, 24B Surge tank 28 Air cleaner 30 Fresh air duct 35A, 35B Intake passage 36 Intercooler 42A , 42B Exhaust manifold 43, 45 Common exhaust passage 54 Transmission case 56 Center differential 58 Rear differential 60 Differential case 62 Power plant 64 Central rotating shaft 66A, 66B Flywheel 70A Main clutch 70B Sub clutch 90 Transmission 110 A to 110 C Mounting member 112 Control circuit 115 Clutch actuator 120 manual switch

Claims (7)

[Claims] 1. A controller for a plurality of engines in a vehicle, comprising: a main engine that is constantly operated; and a sub-engine that is connected to the main engine according to an operating region of the main engine. In a low load region, the sub engine is separated from the main engine, and when the rotational speed of the main engine is a predetermined number of times or more and in an extremely low load state, a control means for connecting the sub engine to the main engine is provided. A control device for a plurality of engines, characterized in that 2. A control device for a plurality of engines in a vehicle, comprising: a main engine that is constantly operated; and a sub engine that is connected to the main engine according to an operating region of the main engine. A control device for a plurality of engines, comprising: a control unit that disconnects the sub engine from the main engine in a low load region and stops the sub engine when the load of the main engine further decreases. 3. A control device for a plurality of engines in a vehicle, comprising: a main engine that is constantly operated; and a sub engine that is connected to the main engine according to an operating region of the main engine. A control device for a plurality of engines, comprising control means for disconnecting the sub-engine from the main engine when cold. 4. A control device for a plurality of engines in a vehicle, comprising: a main engine that is constantly operated; and a sub engine that is connected to the main engine according to an operating region of the main engine, wherein the sub engine is A control device for a plurality of engines, comprising control means for expanding an operating region of the main engine, which is separated from the main engine, when the sub-engine is cold than when it is warm. 5. A control device for a plurality of engines in a vehicle, comprising: a main engine that is constantly operated; and a sub engine that is connected to the main engine according to an operating region of the main engine. A plurality of engines characterized by comprising a selection means capable of selecting a control mode in which the sub-engine is disconnected from the main engine in a low load region and the sub-engine is stopped when the load of the main engine is further reduced. Control device. 6. A control device for a plurality of engines in a vehicle, comprising: a main engine that is constantly operated; and a sub engine that is connected to the main engine according to an operating region of the main engine. A control unit for a plurality of engines, comprising: a selection unit capable of selecting a control mode in which the sub-engine is only disconnected from the main engine in a low load region and the sub-engine is not stopped. 7. A control device for a plurality of engines in a vehicle, comprising: a main engine that is always operated and a sub engine that is connected to the main engine according to an operating region of the main engine, wherein A control device for a plurality of engines, comprising a selection means capable of selecting a control mode for keeping the main engine always connected.