JP2006029211A - Multiple internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multiple internal combustion engine surely and quickly starting a main engine by a sub engine. <P>SOLUTION: In the multiple internal combustion engine starting the main engine 1 by the sub engine 2, a throttle valve 23 of the sub engine 2 is opened after start request of the main engine 1 to increase intake air quantity, and speed and torque are kept roughly constant by retarding ignition timing. After completion of engagement of an electromagnetic clutch 80 engaging the main engine 1 and the sub engine 2, ignition timing is advanced and torque of the sub engine 2 is raised at a burst and the main engine 1 is driven and started. After completion of start, when the electromagnetic clutch is disengaged, ignition timing is retarded again to return torque of the sub engine 2 to normal torque to suppress the generation of vibration and noise. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plurality of internal combustion engines including a main engine for driving and an independent sub engine, and more particularly to a plurality of internal combustion engines capable of starting the main engine by the sub engine.

In a plurality of internal combustion engines in which a sub engine is provided independently of a main engine for driving, a technique for starting the main engine with the sub engine is known (see Patent Document 1). For example, the main engine is dedicated to running, and the auxiliary machine is driven by a smaller sub-engine. When the vehicle stops, such as waiting for a signal, the main engine is stopped, and the power from the air conditioner or the like is supplied from the sub-engine. The main engine is started and restarted by the sub-engine. By using the starter motor for starting the sub-engine itself, the starter motor and the battery can be reduced in size and the efficiency of the main engine and the sub-engine can be realized. .
JP-A-57-76263

  In order to start a main engine that is larger than the sub-engine from a stopped state, a large starting energy that combines inertial energy and driving energy is required. Although the electric motor has a characteristic that the torque increases as the rotational speed decreases, the torque of the internal combustion engine decreases as the rotational speed decreases. For this reason, if a load is suddenly applied to the sub engine, the main engine may not be started, and the sub engine itself may be stopped.

  In order to prevent this, in Patent Document 1, power transmission between the sub-engine and a load (auxiliary machine such as a power steering pump) is temporarily disconnected to increase the output of the sub-engine. However, if the output of the sub-engine is increased so that the output is sufficient to start the main engine as in Patent Document 1, perturbation and noise from the sub-engine increase due to this increase in output. .

  Accordingly, an object of the present invention is to provide a plurality of internal combustion engines that can start a main engine by a sub-engine reliably and quickly.

  In order to solve the above-mentioned problems, a multiple internal combustion engine according to the present invention includes a main engine for driving a vehicle, a sub-engine for driving auxiliary equipment provided separately from the main engine, a sub-engine, and a main engine. Switching the engagement / disengagement of the output shaft of the motor, and a power transmission mechanism that enables power transmission between the two when engaged, and switching the power transmission mechanism to the engaged state to drive the main engine by the sub-engine In a plurality of internal combustion engines comprising a main engine starting means for starting the main engine, an intake air amount for increasing the intake air amount of the sub engine from a predetermined first intake air amount prior to the main engine starting operation by the main engine starting means An increase means, a torque increase suppression means for suppressing a torque increase of the sub engine due to an increase in the intake air amount by the intake air amount increase means, Upon starting the main engine by emissions engine starting means, characterized in that it and a torque restraining stop means for stopping the operation of the torque increase control means.

  Prior to starting the main engine, the intake amount of the sub engine is increased to a state exceeding a predetermined first intake amount (which may be an intake amount during normal operation when the sub engine alone is operated). If the intake air amount is simply increased, the rotational speed increases and the torque rises due to this, but the torque and rotational speed are kept close to the first intake air amount by the torque rise suppression means. By stopping the operation of the torque suppressing means at the time of starting (any time from immediately before the engagement means is started to immediately after completion of the engagement), the torque is increased so that the main engine can be started smoothly. Do.

  When the increase amount of the intake air amount with respect to the first intake air amount is increased, the torque increase suppression means delays the ignition timing of the sub engine, decreases the fuel supply amount to the sub engine, or increases the load of the sub engine. Good. By retarding the ignition timing and decreasing the fuel supply amount, the torque is reduced even with the same intake amount. By increasing the load on the sub-engine, an increase in output torque is suppressed compared to when the load is not increased.

  The intake amount after the increase by the intake amount increasing means is set according to the torque increase suppression amount by the torque increase suppressing means, and the set intake amount after the increase is set to a value lower than the target intake amount at the time of starting the main engine. In this case, it is preferable that the intake air amount increasing means increases the intake air amount of the sub-engine to a predetermined target air amount when stopping the operation of the torque increase suppressing means by the torque suppression stopping means.

  When there is a limit to the amount of torque suppression by the torque increase suppression means, the amount of increase in the intake air amount is suppressed to such an extent that the torque can be suppressed, and the operation is stopped (including the case where the operation is somewhat prior to the operation stop). ) To increase the intake air amount to a desired level, thereby suppressing the torque during operation of the torque increase suppression means.

  The main engine starting means may operate the torque increase suppressing means until the intake amount of the sub engine decreases to the first intake amount after the power transmission mechanism is switched to the disengaged state. If the power transmission mechanism is switched to the disengaged state after the main engine is started, the sub engine speed and torque may increase due to a sudden decrease in load. By means, an increase in rotational speed and an increase in torque are suppressed.

  According to the present invention, the intake amount to the sub-engine is increased in advance before starting the main engine, while the increase in rotational speed and torque is suppressed by the torque increase suppressing means, so that the load is small before starting. Generation of vibration and noise from the sub-engine can be suppressed. Then, by stopping the operation of the torque increase suppressing means at the time of starting, the torque can be quickly increased and the main engine can be operated reliably with a small sub-engine. Although a relatively long response time is required for an increase in torque due to an increase in intake air amount, it is possible to quickly restart from a main engine stop state while waiting for a signal, for example, by controlling the torque by means of faster response. Can be done.

  As the torque increase suppression means, if the load adjustment to the sub-engine is performed by driving the ignition timing, fuel supply amount, auxiliary machinery, etc., the torque can be increased with good responsiveness when the main engine is started.

  Depending on the torque suppression amount by the torque increase suppression means, the increase in the intake air amount may be set in two stages. In this case, during the operation of the torque increase suppression means, the increase in the rotation speed and torque of the sub-engine is surely suppressed to suppress the generation of vibration and noise.

  When switching to the non-engagement state, the torque suppression means is activated until the intake air volume decreases reliably, thereby suppressing the occurrence of blow-up due to the disconnection of the sub-engine and the noise / vibration from the sub-engine. Can be reliably suppressed.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.

  FIG. 1 is a schematic configuration diagram of a drive system of a vehicle provided with an exhaust gas purifying apparatus according to the present invention. This vehicle is provided with a sub-engine 2 for driving auxiliary equipment in addition to the main engine 1 for driving. Both the main engine 1 and the sub-engine 2 are internal combustion engines that use gasoline as fuel, for example, and the sub-engine 2 is an internal combustion engine that has a smaller displacement than the main engine 1. For example, the main engine 1 is a multi-cylinder type. On the other hand, the sub-engine 2 is a single cylinder type.

The main engine 1 is connected to an intake pipe 12 via an intake manifold 15 and an exhaust pipe 17 via an exhaust manifold 16. On the intake pipe 12, an air cleaner 11, a throttle valve 13, and a fuel injection valve 14 are arranged from the upstream side. On the other hand, an exhaust purification catalyst 40 is disposed on the exhaust pipe 17, O ₂ sensors 42 and 43 are disposed on the upstream side and the downstream side, respectively, and a temperature sensor 41 is connected to the catalyst 40. . A muffler 44 is disposed on the downstream side of the catalyst 40. The output shaft of the main engine 1 is connected to the transmission 3, and the driving force is transmitted from the transmission 3 to driving wheels (not shown).

  An intake pipe 22 and an exhaust pipe 27 are connected to the sub-engine 2. An air cleaner 21, a throttle valve 23, and a fuel injection valve 24 are arranged on the intake pipe 22 from the upstream side in the same manner as the intake pipe 12 of the main engine 1. Is arranged. On the other hand, the exhaust pipe 27 is connected to a position upstream of the catalyst 40 in the exhaust pipe 17 of the main engine 1. Hereinafter, this connecting portion is referred to as a collecting portion 18. The output shaft of the sub-engine 2 is connected to a compressor or generator of an air conditioner (not shown) and drives auxiliary equipment.

  FIG. 2 is a schematic configuration diagram of the sub-engine 2 main body. The sub-engine 2 includes a cylinder block 200 in which a cylinder 201 is formed, and a cylinder head 210 fixed to the upper part of the cylinder block 200. A crankshaft 220 is rotatably supported on the cylinder block 200. A piston 202 loaded in the cylinder 201 so as to be reciprocally movable in the vertical direction in the figure is connected to the crankshaft 220 by a connecting rod (connecting rod) 203, whereby reciprocating motion of the piston 202 is coupled to the crankshaft 220. Converted to rotational motion. The crankshaft 220 is provided with a crank angle sensor 215 that detects a crank rotation angle.

  A combustion chamber 204 is formed above the piston 202 surrounded by the top surface of the piston 202, the wall surface of the cylinder 201, and the bottom surface of the cylinder head 210. A spark plug 205 is attached to the bottom surface of the cylinder head 210 so as to face the combustion chamber 204.

  The connection port of the cylinder head 210 with the intake pipe 22 is opened and closed by an intake valve 206 supported by the cylinder head 210 so as to be able to advance and retract. The valve opening / closing timing and the lift amount of the intake valve 206 can be adjusted by an intake valve drive unit 208 provided in the cylinder head 210.

  Similarly, the connection port of the cylinder head 210 with the exhaust pipe 27 is opened and closed by an exhaust valve 207 supported by the cylinder head 210 so as to be able to advance and retract. The valve opening / closing timing and the lift amount of the exhaust valve 207 can be adjusted by an exhaust valve driving unit 209 provided in the cylinder head 210.

  The main engine 1 and the sub-engine 2 can be switched between an engaged state and a disengaged state by an electromagnetic clutch 80 and a belt drive 81. The main engine 1 and the sub engine 2 are engaged, and the main engine 1 can be started by the sub engine 2. The sub-engine 2 itself is started by the starter motor 70 by being engaged by the starter motor 70 and the electromagnetic clutch 71.

The main engine 1 and the sub engine 2 are controlled by the engine ECU 5. The engine ECU 5 includes a CPU, a ROM, a RAM, and the like. The outputs of the temperature sensor 41, the O ₂ sensors 42, 43, and the crank angle sensor 215 are input, and the throttle valves 13, 23, the fuel injection valve 14, 24, controls the operation of the intake valve / exhaust valve drive units 208 and 209 and the spark plug 205. Fuel is supplied from the fuel tank 6 to the fuel injection valves 14 and 24.

  The operation of this embodiment will be briefly described. First, at the start, the starter motor 70 and the sub-engine 2 are engaged by the electromagnetic clutch 71 and the sub-engine 2 is driven by the starter motor 70. When the rotational speed reaches a desired rotational speed, the fuel injection valve 24 Fuel is injected and ignition is performed by the spark plug 205 to start combustion of the sub-engine 2, thereby starting the sub-engine 2. After startup, the electromagnetic clutch 71 is disconnected and the drive of the starter motor 70 is stopped.

  The main engine 1 is engaged with the sub engine 2 by the electromagnetic clutch 80 and the belt drive 81, and the main engine 1 is driven by the sub engine 2. Similarly, when the desired rotational speed is reached, the fuel injection valve 14 supplies the fuel. Is started by injecting and starting combustion.

  When the vehicle travels, the driving force is transmitted from the main engine 1 to the driving wheels through the transmission 3. On the other hand, the sub-engine 2 drives an auxiliary machine or the like. When the vehicle is stopped due to a signal waiting or the like, the main engine 1 is stopped to suppress emission of exhaust gas and improve fuel efficiency. On the other hand, since the auxiliary machine such as an air conditioner is driven by the sub-engine 2, it is not necessary to drive the main engine 1 only for driving the auxiliary machine, and the main engine 1 is surely stopped when the vehicle is stopped. Can do. In addition, since the driving force of the main engine 1 can be used only for traveling even while the main engine 1 is operating, it is possible to set an appropriate driving condition according to the traveling state, and the responsiveness is also improved.

  The sub-engine 2 includes a case where it is not necessary to drive the auxiliary machine (a case where there is no load of the auxiliary machine and a case where the battery capacity is sufficient and the load of the auxiliary machine can be covered by power supply from the battery. ) May be stopped even while the main engine 1 is being driven. However, when the main engine 1 is stopped by waiting for a signal or the like, it is preferable to restart the sub-engine 2 in preparation for the restart.

  Hereinafter, the start / restart control of the main engine 1 by the sub-engine 2 will be specifically described. FIG. 3 is a flowchart showing a first control mode of the start / restart control.

  First, it is determined whether or not the main engine 1 is stopped, the sub-engine 2 is in operation, the main engine 1 is requested to start, and all requirements for satisfying the start condition are satisfied (step S1). Here, the start request of the main engine 1 is an operation of turning on an engine start switch at the time of start, and corresponds to a start operation by a driver from a vehicle stop state. Examples of the starting condition include depression of an accelerator pedal.

  If any of the conditions is not satisfied, it is determined that the main engine 1 cannot be started / restarted by the sub-engine 2 and the process is terminated. Only when all the conditions are satisfied, shift to actual start control.

In the start control, first, the opening degree θ of the throttle valve 23 is increased by a predetermined amount Δθ from the present time (step S2). Then, the ignition timing t _i of the sub-engine 2 is delayed by a predetermined amount Δt _i from the current time (step S3). Opening the throttle opening increases the amount of air, and usually increases the rotational speed and torque. However, by delaying the ignition timing, this increase in torque is suppressed. For this reason, generation | occurrence | production of the noise and vibration by the rotation speed of the sub engine 2 increasing prior to starting is suppressed.

  Next, it is determined whether the amount of increase in the rotation speed of the sub-engine 2 is equal to or greater than a predetermined value or the combustion fluctuation is within a set value (step S4). If the condition is satisfied, it is determined that the amount of torque suppression is insufficient and further torque suppression is possible, and the process returns to step S3. On the other hand, if any of the conditions is not satisfied, it is determined that torque suppression is sufficient, or that further suppression makes the combustion state of the sub-engine 2 unstable, and the process proceeds to step S5.

  In step S5, it is determined whether or not the intake air amount has reached the target air amount (the target air amount under the operating conditions for starting the main engine 1). When the intake air amount has not reached the target air amount, the opening of the throttle valve 23 is further opened by returning to step S2. When the target air amount is reached, the process proceeds to step S6. As a result, the amount of air supplied to the sub-engine 2 is increased prior to starting the main engine 1. Here, by setting Δθ in step S2 to a level at which the increase in air amount can actually follow while the processing from steps S2 to S4 is completed, the air amount can be adjusted reliably. preferable.

  In step S6, the engine ECU 5 instructs the electromagnetic clutch 80 to be engaged. In step S7, the process waits until the electromagnetic clutch 80 is completely engaged. If it is determined that the coupling is completed, the ignition timing is advanced and set to a predetermined ignition timing (step S8). As a result, torque suppression is released, and the torque of the sub-engine 2 increases instantaneously, but since the main engine 1 is engaged, the rotation speed is maintained substantially the same. Thereby, the main engine 1 can be started reliably.

  In step S9, the process waits until the main engine 1 is started. When the main engine 1 is started, the throttle valve 23 is throttled to return the throttle opening and ignition timing to normal operating conditions (step S10). Exit.

FIG. 4 is a timing chart during the start control. When the start request of the main engine 1 is turned on at time t ₀ , the throttle valve 23 of the sub engine 2 starts to open slightly later than this, and the ignition timing is retarded accordingly. In order to suppress the increase in the rotational speed / torque accompanying the increase in the intake air amount by retarding the ignition timing, the rotational speed / torque is maintained substantially constant.

When the opening of the throttle valve 23 is set to the set opening for starting the main engine 1 (time t ₁ ), the main engine 1 and the sub engine 2 are engaged by the electromagnetic clutch 80 with a slight delay (time). t _2). When the engagement is confirmed, the ignition timing is advanced instantaneously (time t ₃ ). As a result, the torque of the sub-engine 2 increases instantaneously, but the main engine 1 becomes a load, so the rotation speed of the sub-engine 2 does not increase and is kept substantially constant.

In order to increase the throttle opening, it takes time from time t _{0 to} time t _{1 due} to the characteristics of the motor driving the throttle valve 23, and the throttle valve 23 is opened due to the influence of the volume of the intake pipe 22 and flow resistance. Even after the intake air amount to the combustion chamber 204 actually increases, a time delay occurs. For this reason, when the amount of intake air is increased after engagement, a delay in torque increase occurs. FIG. 5 is a graph comparing typical rotational speed-torque characteristics in the case of an electric motor and in the case of an internal combustion engine such as a gasoline engine, but is compared with an electric motor capable of generating high torque even at a low speed. However, a gasoline engine or the like has a characteristic that the torque rapidly decreases when the rotational speed becomes a predetermined value or less. For this reason, when trying to start the main engine 1 by engaging the operating sub engine 2 with the stopped main engine 1, the main engine 1 becomes a load if the torque increase of the sub engine 2 is small. As a result, the rotational speed of the sub-engine 2 is reduced, and thus the torque is further reduced, so that not only the start of the main engine 1 fails, but also the sub-engine 2 itself may stop. .

  In the present embodiment, since the intake air amount is increased in advance and the ignition timing is advanced to increase the torque instantaneously after engagement, the occurrence of such a reduction in rotational speed and torque reduction is prevented. The main engine 1 can be reliably started without stopping the sub-engine 2. In addition, the torque generated by retarding the ignition timing is suppressed before the engagement, and the rotation amount is maintained at the same rotation amount as during normal operation. Can be suppressed.

The rotational speed of the main engine 1 itself is affected by the slip of the electromagnetic clutch 80, and starts to increase slightly after the completion of the engagement of the electromagnetic clutch 80 (time t ₄ ), and when the predetermined rotational speed is reached, fuel injection is performed. Fuel injection from the valve 14 and ignition are performed and the engine is started.

When the rotational speed of the main engine 1 reaches a predetermined rotational speed (time t5), the electromagnetic clutch 80 is disconnected, and at the same time, the ignition timing of the sub engine 2 is retarded. Accordingly, the torque of the sub-engine 2 and returned to the same point of the rotational speed until time t _3. And while we return the opening degree of the throttle valve 23, it takes this to time t ₅ ~t ₆ is during this time, since by retarding the ignition timing in accordance with the opening degree of the throttle valve 23, An increase in torque and rotation speed of the sub engine 2 can be suppressed, and noise and vibration generated from the sub engine 2 can be suppressed.

  According to the present embodiment, the main engine 1 can be started even by the sub-engine 2 having a relatively small inertial energy, so that the mass of moving parts such as a counterweight can be reduced, and it is also necessary to increase the rotational speed. Therefore, the effect of reducing noise and vibration generated from these can be obtained.

  Note that the ignition timing is also limited in the advance-retard angle range in order to stably perform the combustion in the combustion chamber 204. For this reason, there is a limit to the amount of torque control by controlling the ignition timing. When the intake air amount set at the time of starting the main engine 1 (referred to as starting air amount) is controlled, even when the torque amount that is expected to increase from the normal time is retarded to the maximum, it is completely achieved. If it cannot be suppressed, the increase amount of the intake air amount is kept to such an extent that the torque can be suppressed by retarding the angle, and includes when the electromagnetic clutch 80 is engaged (from immediately before to immediately after the engagement). The intake air amount should be increased to the starting air amount.

  FIG. 6 is a process flowchart of this control mode (second control mode), and FIG. 7 shows a timing chart in this case.

  The processing of steps S1 to S4 is basically the same as the first control mode described above. However, instead of step S5, it is determined whether or not the ignition timing can be further retarded. Only when it is possible to retard the angle, the process returns to step S2, and when the limit is reached, the process proceeds to step S6. As a result, before starting the main engine 1, the intake air amount is previously increased to the maximum within a range in which the torque and the rotational speed can be maintained.

In Steps S6 and S7, when the engagement of the sub engine 2 and the main engine 1 by the electromagnetic clutch 80 is completed, the process proceeds to Step S8, and the ignition timing is advanced by a predetermined amount. As a result, the torque suppression is released, and the torque of the sub-engine 2 increases instantaneously. Thereafter, the opening degree θ of the throttle valve 23 is increased by a predetermined amount Δθ from the present time (step S12). Then, the ignition timing t _i of the sub-engine 2 is accelerated by a predetermined amount Δt _i from the current time (step S13). This further increases the torque. Next, it is determined whether or not the rotation speed of the sub-engine 2 has reached a predetermined rotation speed (step S14). If the condition is not satisfied, it is determined that the torque needs to be further increased, and the process returns to step S12. If the condition is satisfied, the torque increase process is completed and the process proceeds to the next step S9. And wait until the start of the main engine 1 is completed. When the start of the main engine 1 is completed, the throttle valve 23 is throttled, the throttle opening and the ignition timing are returned to normal operating conditions (step S10), and the process is terminated.

  Also in this control mode, the same effect as in the first control mode can be obtained. As shown in FIG. 7, in this control mode, as in the first control mode shown in FIG. 4, when the main engine 1 and the sub-engine 2 are engaged by the electromagnetic clutch 80, the rotation speed of the sub-engine 2 is set. It can be kept substantially the same. Further, with regard to the torque of the sub-engine 2, the torque of the sub-engine 2 can be instantaneously increased at the time of engagement, and the torque can be instantaneously decreased at the time of disconnection, thereby effectively suppressing the generation of noise and vibration. Can do.

  The torque suppression control of the sub-engine 2 before the engagement with the main engine 1 can be performed by controlling the fuel injection amount or increasing the load on the auxiliary machine, in addition to the retarding of the ignition timing described above. is there. Hereinafter, processing of these control modes will be described.

  FIG. 8 is a process flowchart of the third control mode. The basic processing is the same as in the first control mode. First, the starting requirement is determined (step S1), and the opening degree θ of the throttle valve 23 is increased by a predetermined amount Δθ from the present (step S2), which is the same as in the first control mode. Next, the fuel injection amount from the fuel injection valve 24 is reduced by a predetermined amount to make it lean (step S21). By opening the throttle opening, the amount of air is increased, and the rotational speed and torque are normally increased. However, the increase in torque is suppressed by reducing the fuel injection amount and performing lean combustion. For this reason, generation | occurrence | production of the noise and vibration by the rotation speed of the sub engine 2 increasing prior to starting is suppressed.

  The subsequent steps S4 to S7 are common to the first control mode. If it is determined that the coupling has been completed, the fuel injection amount is increased to bring the fuel into the vicinity of the stoichiometric air-fuel ratio or a richer state (step S22). As a result, torque suppression is released, and the torque of the sub-engine 2 increases instantaneously, but since the main engine 1 is engaged, the rotation speed is maintained substantially the same. Thereby, the main engine 1 can be started reliably.

  Subsequently, in step S9, the process waits until the main engine 1 is started. When the main engine 1 is started, the throttle valve 23 is throttled, and the fuel injection amount is reduced accordingly to maintain the stoichiometric air-fuel ratio ( Step S23) The process is terminated.

  Also in this control mode, the intake air amount with poor responsiveness is increased in advance, and the fuel injection amount with good responsiveness is adjusted so that the rotational speed / torque of the sub-engine 2 is engaged before the main engine 1 is engaged. The increase of the fuel pressure is suppressed, the fuel injection amount is increased at the time of engagement, and combustion is performed in the vicinity of the theoretical air-fuel ratio, so that the torque can be increased at once and the main engine 1 can be started reliably. And generation | occurrence | production of the noise and vibration from the sub engine 2 can be suppressed effectively.

  FIG. 9 is a process flowchart of the fourth control mode. The basic processing is the same as in the first and third control modes. First, the starting requirement is determined (step S1), and the opening degree θ of the throttle valve 23 is increased by a predetermined amount Δθ from the present time (step S2), which is the same as the first and third control modes. Next, the load on the auxiliary machine is increased (step S31). For example, the amount of power generated by a generator may be increased, or the work amount of a power steering pump or an air conditioner compressor may be increased. Opening the throttle opening increases the amount of air and normally increases the rotation speed and torque. However, increasing the load on the auxiliary equipment suppresses the increase in the rotation speed, so the increase in torque is suppressed. . For this reason, generation | occurrence | production of the noise and vibration by the rotation speed of the sub engine 2 increasing prior to starting is suppressed.

  The subsequent steps S4 to S7 are common to the first control mode. If it is determined that the coupling has been completed, the load on the auxiliary machine or the like that has been increased is decreased (step S22). As a result, torque suppression is released, and the torque of the sub-engine 2 increases instantaneously, but since the main engine 1 is engaged, the rotation speed is maintained substantially the same. Thereby, the main engine 1 can be started reliably. At this time, it is preferable to reduce the load of the auxiliary machine from the normal time because the amount of torque that can be used for starting the main engine 1 out of the torque of the sub engine 2 can be increased.

  In step S9, the process waits until the start of the main engine 1 is completed. When the start of the main engine 1 is completed, the throttle valve 23 is throttled (step S23) and the process is terminated. If the load on the auxiliary machine or the like has been reduced from the normal time when the main engine 1 is started, the load on the auxiliary machine or the like may be returned to the normal time here.

  Even in this control mode, the amount of intake air with poor responsiveness is increased in advance, and the speed of the sub-engine 2 before the engagement with the main engine 1 is adjusted by adjusting the load of auxiliary equipment with good responsiveness. -By suppressing the increase in torque and reducing the load of the auxiliary machine or the like at the time of engagement, the torque can be increased at a stretch and the main engine 1 can be started reliably. And generation | occurrence | production of the noise and vibration from the sub engine 2 can be suppressed effectively.

  These first to fourth control modes may be appropriately combined or replaced. For example, when the first and third control modes are combined and torque suppression is performed by both the fuel injection amount and the ignition timing, the adjustment amount can be increased compared to the case where only one of them is performed.

  In the above description, the throttle opening degree is opened after the start request, torque suppression control is executed, and after the engagement of the electromagnetic clutch is completed, the torque suppression is released to increase the torque. However, the control timing is not limited to this.

  For example, when the main engine 1 is stopped by waiting for a signal or the like, the throttle opening of the sub-engine 2 is opened during the stop, torque suppression control is executed, and the driver performs a start operation. You may make it cancel | release torque suppression by engaging an electromagnetic clutch. If it does in this way, the startability at the time of start will improve. The release of torque suppression is not limited to immediately after the engagement of the electromagnetic clutch is completed. It may be performed slightly prior to the engagement command of the electromagnetic clutch, or the torque suppression may be released simultaneously with the engagement command. After the electromagnetic clutch 71 is engaged, the main engine 1 starts to be driven by the slip of the clutch. You may go in between. Further, torque suppression may be gradually released during this time.

  Here, the main engine 1 and the sub-engine 2 of the type in which gasoline is used as fuel and fuel is injected into the intake pipes 12 and 22 to form a premixed gas have been described. It is good also as an engine of the type which injects directly into. Further, the present invention can also be suitably applied to a plurality of internal combustion engines that use diesel engines or LPG (liquefied petroleum gas) as fuel.

It is a schematic block diagram of the drive system of the vehicle provided with the exhaust gas purification apparatus concerning this invention. It is a schematic block diagram of the sub-engine 2 main body of FIG. 3 is a flowchart showing a first control mode of start / restart control of the main engine 1 of FIG. 1. It is a timing chart at the time of control of FIG. It is the graph which compared the typical rotation speed-torque characteristic in an electric motor and a gasoline engine. 6 is a flowchart showing a second control mode of start / restart control of the main engine 1 of FIG. 1. It is a timing chart at the time of control of FIG. 6 is a flowchart showing a third control mode of start / restart control of the main engine 1 of FIG. 1. 7 is a flowchart showing a fourth control mode of start / restart control of the main engine 1 of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Main engine, 2 ... Sub engine, 3 ... Transmission, 5 ... Engine ECU, 6 ... Fuel tank, 11, 21 ... Air cleaner, 12, 22 ... Intake pipe, 13, 23 ... Throttle valve, 14, 24 ... Fuel injection Valve 15, Intake manifold 16, Exhaust manifold 17, 27 Exhaust pipe 18, Collecting part 40 Exhaust purification catalyst 41 Temperature sensor 42 O ₂ sensor 44 Muffler 70 Starter motor 71, 80 ... Electromagnetic clutch, 81 ... Belt drive, 200 ... Cylinder block, 201 ... Cylinder, 202 ... Piston, 204 ... Combustion chamber, 205 ... Spark plug, 206 ... Intake valve, 207 ... Exhaust valve, 208 ... Each drive unit 208: Intake valve drive unit, 209: Exhaust valve drive unit, 210 ... Cylinder head, 215 ... Crank angle sensor, 2 20 ... Crankshaft.

Claims (6)

A main engine for driving the vehicle, a sub-engine for driving auxiliary equipment provided separately from the main engine, and switching between engagement / disengagement of the output shaft of the sub-engine and the main engine; A power transmission mechanism that enables power transmission between the two at the time of switching, and a main engine starting means that switches the power transmission mechanism to an engaged state and drives the main engine by the sub-engine to start the main engine. In a multiple internal combustion engine comprising:
An intake air amount increasing means for increasing the intake air amount of the sub engine before a predetermined first intake air amount prior to the main engine starting operation by the main engine starting means;
Torque increase suppression means for suppressing an increase in torque of the sub-engine accompanying an increase in intake air amount by the intake air amount increasing means;
Torque suppression stop means for stopping the operation of the torque increase suppression means when the main engine is started by the main engine start means;
A plurality of internal combustion engines.   2. The multiple internal combustion engine according to claim 1, wherein the torque increase suppression unit retards the ignition timing of the sub-engine as the amount of increase in the intake air amount with respect to the first intake air amount increases.   2. The multiple internal combustion engine according to claim 1, wherein the torque increase suppression unit decreases the fuel supply amount to the sub-engine as the increase amount of the intake air amount with respect to the first intake air amount increases.   2. The multiple internal combustion engine according to claim 1, wherein the torque increase suppression unit increases the load of the sub-engine as the amount of increase in the intake air amount with respect to the first intake air amount increases.   The intake air amount increased by the intake air amount increasing means is set according to the torque increase suppression amount by the torque increase suppressing means, and the set intake air amount after the increase is less than the target intake air amount at the time of starting the main engine The intake air amount increasing means increases the intake air amount of the sub engine to a predetermined target air amount when the torque suppression stopping means stops the operation of the torque increase suppressing means. The multiple internal combustion engine according to any one of claims 1 to 4.   The main engine starting means operates the torque increase suppressing means until the intake amount of the sub engine decreases to the first intake amount after the power transmission mechanism is switched to the disengaged state. The multiple internal combustion engine according to any one of claims 1 to 5, wherein

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