JP2010071291A - Engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform stable operation by properly adjusting the intake temperature. <P>SOLUTION: This engine 11, mainly, a premixed compressed self-ignition type engine is provided for burning an air-fuel mixture of fuel and air in a combustion chamber in a cylinder, and includes a heating system for heating intake air to the combustion chamber. The heating system is comprises: a first heat exchanger of using a first heat exchange medium; and a second heat exchanger of using a second heat exchange medium different from the first heat exchange medium. A flow regulating valve is respectively arranged for adjusting a supply flow rate of the respective heat exchange media to the respective heat exchangers. The intake temperature is adjusted by the heating system so that the intake temperature is set in a predetermined target value and/or a combustion parameter for indicating a combustion state in the combustion chamber is set to a predetermined target value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine that burns a mixture of air and fuel in a combustion chamber in a cylinder.

  As an engine of this type, for example, Patent Document 1 discloses a premixed compression type self-ignition system in which an air-fuel mixture in which air and fuel are mixed in advance is supplied to a combustion chamber in a cylinder and the mixture is compressed to self-ignite. An ignition engine is disclosed.

  This premixed compression self-ignition engine has an advantage of high thermal efficiency because it can be operated at a higher compression ratio than a spark ignition engine. In addition, since the combustion temperature can be lowered, it is possible to suppress the generation of NOx. However, since the air-fuel mixture is ignited naturally, it is difficult to control the ignition timing, and it is important to prepare conditions for appropriate ignition.

  The self-ignition of the air-fuel mixture greatly depends on the engine torque and the intake air temperature of the air-fuel mixture. The hatched region Z in FIG. 3 is a range in which compression auto-ignition operation is possible due to the relationship between the engine torque and the intake air temperature of the air-fuel mixture, and when the torque and intake air temperature deviate from this limited range, Knocking and misfire are likely to occur. Therefore, it is an important problem how to prepare the conditions so that the torque and the intake air temperature are within the range where the compression ignition operation can be performed. In order to obtain an appropriate combustion state (ignition timing, etc.), it is necessary to appropriately control the intake air temperature.

JP 2005-69097 A

  In view of the above circumstances, the present invention appropriately adjusts the intake air temperature in order to set the intake air temperature to a predetermined target value and / or to set the combustion parameters such as the ignition timing to the predetermined target value. The purpose is to make the operation possible.

In order to solve the above problems, the invention of claim 1
A premixed compression auto-ignition engine that burns by compressing and igniting an air-fuel mixture premixed with fuel and air in a combustion chamber in a cylinder at least in steady operation,
A heating device for heating the intake air to the combustion chamber;
The heating device includes a first heat exchanger using a first heat exchange medium and a second heat exchanger using a second heat exchange medium different from the first heat exchange medium;
A flow rate adjusting valve for adjusting a supply flow rate of each heat exchange medium to each heat exchanger is provided,
The intake air temperature is adjusted by the heating device so as to set the intake air temperature to a predetermined target value and / or to set a combustion parameter indicating the combustion state in the combustion chamber to a predetermined target value. It is characterized by being.

  The invention of claim 2 is characterized in that the heating device is constituted by a heat exchanger using exhaust gas as a heat exchange medium.

  The invention of claim 3 is characterized in that the heating device is constituted by a heat exchanger using engine cooling water as a heat exchange medium.

  The invention of claim 4 is characterized in that the heating device is constituted by a heat exchanger using engine lubricating oil as a heat exchange medium.

According to a fifth aspect of the present invention, in the cold operation of the engine, each of the heat exchange media starts after the temperature of the heat exchange medium becomes higher than the target value of the intake air temperature. The flow control valve is controlled,
Further, when both of the first and second heat exchange media are higher than the target value, the flow rate for adjusting the flow rate of the heat exchange medium having the lower temperature among the first and second heat exchange media. The adjustment valve is controlled to be fully open, and the flow rate adjustment valve that adjusts the flow rate of the heat exchange medium having a higher temperature is controlled to adjust the flow rate according to the target value.

  According to the first aspect of the present invention, in the premixed compression self-ignition engine in which the intake air is heated by the heating device including the first heat exchanger and the second heat exchanger, the first heat exchange medium and the second heat The intake air temperature can be increased efficiently by starting the supply of the corresponding heat exchange medium after the temperature of the exchange medium becomes higher than the target value of the intake air temperature.

  According to the invention of claim 2, since the heating device is constituted by a heat exchanger that uses exhaust gas as a heat exchange medium, compared with the case of using an electric heater, a glow plug, and a flame burner, There is no consumption, and deterioration of energy efficiency can be prevented.

  According to the invention of claim 3, since the heating device is constituted by a heat exchanger that uses engine cooling water as a heat exchange medium, the consumption of electric power and fuel compared to the case of using an electric heater, a flame burner, or the like. In addition, the temperature is more stable than when exhaust gas is used, and accurate temperature adjustment becomes possible.

  According to the invention of claim 4, since the heating device is constituted by a heat exchanger that uses engine lubricating oil as a heat exchange medium, consumption of electric power and fuel compared to the case of using an electric heater, a flame burner, or the like. As compared with the case where exhaust gas is used, the temperature is stabilized and accurate temperature adjustment is possible. Moreover, since engine lubricating oil becomes high temperature compared with engine cooling water, the capacity | capacitance of a heat exchanger can be made small.

  According to the fifth aspect of the present invention, the intake air temperature can be efficiently increased by starting the supply of the heat exchange medium after the temperature of the heat exchange medium becomes higher than the target value of the intake air temperature. Furthermore, when the temperature of both the first and second heat exchange media becomes higher than the target value of the intake air temperature, the intake air temperature can be increased more efficiently by effectively using the difference between the temperatures. it can.

1 is a schematic cross-sectional view of an engine according to an embodiment of the present invention. It is the same schematic plan view. It is a graph which shows the area | region which can be drive | operated by the relationship between a net average effective pressure and intake air temperature. It is a graph which shows a target intake air temperature map. It is a control logic figure of an engine concerning an embodiment. It is a graph explaining the application control 2 using the allowable maximum target torque map. It is a graph explaining the application control 2 using the allowable minimum target torque map. It is a control logic figure which shows the limiter of target torque. It is a graph explaining the exception of application control 2. FIG. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a schematic plan view which shows other embodiment of a heating apparatus. It is a graph which shows the change of the cooling water temperature and lubricating oil temperature with progress of time at the time of engine cold state.

[First Embodiment]
[Outline of premixed compression self-ignition engine]
FIG. 1 is a schematic sectional view of a premixed compression self-ignition engine 11 according to an embodiment of the present invention, and FIG. 2 is a schematic plan view thereof. The premixed compression self-ignition engine 11 of this embodiment is a four-cylinder four-cycle engine, and includes an engine main body 11 </ b> A configured by a cylinder block 12, a cylinder head 15, and a crankcase 18. A plurality (four) of cylinders (cylinders) 13 are provided in the cylinder block 12, and a piston 14 is slidably fitted in each cylinder 13. The cylinder head 15 is provided with an intake port 16 and an exhaust port 17, and the intake port 16 and the exhaust port 17 are opened and closed by an intake valve 19 and an exhaust valve 20, respectively. The intake valve 19 and the exhaust valve 20 are driven by valve gears 21 and 22.

  An intake pipe 24 is connected to the intake port 16, and an exhaust pipe 26 having an exhaust manifold 25 is connected to the exhaust port 17. As shown in FIG. 2, the intake pipe 24 includes a main intake pipe 27, an intake surge tank 28 connected to the main intake pipe 27, and a plurality of branched intake pipes connected from the intake surge tank 28 to each cylinder 13. Tube 29.

  As shown in FIG. 1, the main intake pipe 27 is provided with a throttle valve 31, a mixer 33, and a heating device (temperature control device) 35. The air introduced into the main intake pipe 27 is adjusted in flow rate by the throttle valve 31 and mixed with the fuel injected from the fuel control valve 32 by the mixer 33. The mixture of air and fuel is heated by the heating device 35 and flows into the intake surge tank 28, and is sucked into the combustion chambers in the cylinders 13 from the branch intake pipes 29 through the intake ports 16 (intake stroke). . The air-fuel mixture supplied into the combustion chamber in the intake stroke is compressed in the compression stroke, and is ignited when the piston 14 comes near the top dead center, thereby pushing down the piston (expansion stroke). The combustion gas is discharged from the exhaust port 17 through the exhaust pipe 26 in the exhaust stroke.

  As described above, the premixed compression self-ignition engine 11 performs compression self-ignition of the air-fuel mixture. In this embodiment, the cylinder head 15 is provided with an ignition plug (ignition device) 37 for spark-igniting the air-fuel mixture. Yes. The spark plug 37 is used during operation by spark ignition.

  That is, the premixed compression ignition type engine 11 of the present embodiment performs the compression self-ignition operation during the steady operation, but can also be operated by spark ignition. And when performing only the compression self-ignition operation, the spark ignition is turned off.

  As will be described later, the heating device 35 heats the air-fuel mixture to an appropriate temperature in order to operate the engine 11 stably. As shown in FIG. 2, the heating device 35 of the present embodiment is configured by a heat exchanger 40 provided in one path 38 of the main intake pipe 27 branched into two paths. The heat exchanger 40 uses engine cooling water as a heat exchange medium, and the cooling water circulated through the cylinder block 12 and the cylinder head 15 is supplied to the heat exchanger 40 via the flow path 41 and the flow path. It is returned to the cooler (not shown) via 42. Metering valves 43 and 44 are provided in both paths 38 and 39 of the main intake pipe 27, respectively.

  The heat exchanger 49 is not provided in the other path 39 of the main intake pipe 27, and the air-fuel mixture passing through the path 39 is introduced into the intake surge tank 28 without being heated. The metering valves 43 and 44 adjust (including stop) the inflow amount of the air-fuel mixture into the paths 38 and 39 of the main intake pipe 27. For example, only one of the metering valves 43 is opened. The air-fuel mixture can be heated rapidly by passing the air-fuel mixture only through 38, and only the other metering valve 44 is opened and the air-fuel mixture is passed through only the passage 39 so that the air-fuel mixture is not heated. (Relative cooling). Further, by opening both the metering valves 43 and 44, the heated air-fuel mixture and the unheated air-fuel mixture can be mixed to perform fine temperature control.

  As shown in FIG. 1, the engine 11 includes a controller 45, and the ignition plug 37, the throttle valve 31, the fuel control valve 32, the heating device 35, and the like are controlled by the controller 45. The engine 11 is provided with a cooling water temperature sensor 47, an intake air temperature sensor 48, an in-cylinder pressure sensor 49, an engine speed sensor 50, a torque sensor 51, and the like. To be input.

[Control of premixed compression self-ignition engine]
In FIG. 3, the region Z in which the premixed compression self-ignition operation is possible is indicated by hatching based on the relationship between the torque of the premixed compression self-ignition engine 11 and the intake air temperature. That is, when both the torque and the intake air temperature are within the region Z, stable operation can be performed.

  In the present invention, when an operator or the like inputs a desired torque (target torque) to the controller 45 (FIG. 1), the intake air temperature is set so that the intake air temperature is within the region Z in relation to the target torque. It comes to control. Details of the control will be described below.

(Basic control)
A memory in the controller 45 stores a target intake air temperature map MA. The target intake air temperature map MA is obtained by recording the target torque and the target intake air temperature that correspond appropriately with each other in the region Z shown in FIG. 3, and the target intake air temperature map MA is shown in a substantially linear shape on FIG. Has been. The engine 11 of the present embodiment is controlled using this target intake air temperature map MA.

  With reference to FIG. 4, the basic control of this embodiment is demonstrated. For example, it is assumed that the engine 11 is operated with the torque T1 and the intake air temperature Tm1. In this case, since the torque T1 and the intake air temperature Tm1 are arranged on the target intake air temperature map MA, it is considered that stable operation is performed. From this state, T2 is input to the controller 45 as the target torque. Then, the controller 45 selects the target intake air temperature Tm2 corresponding to T2 in consideration of the target intake air temperature map MA in the memory. Since the target intake air temperature Tm2 is higher than the intake air temperature Tm1 so far, the controller 45 is heated by the heating device 35 shown in FIG. 2 so that the air-fuel mixture reaches the target intake air temperature Tm2. By performing such control, the air-fuel mixture is adjusted to an appropriate temperature Tm2 corresponding to the target torque T2.

  In the opposite case, for example, when the target torque T1 is applied from the state where the engine is operating at the torque T2 and the intake air temperature Tm2, the target intake air temperature Tm1 is selected from the target intake air temperature map in the same manner as described above. Adjust the intake air temperature. In this case, the intake air temperature is lowered from Tm2 to Tm1 by lowering the temperature of the heating device.

  FIG. 5 is a control logic diagram of this embodiment. The basic control described above will be explained using this control logic diagram. First, a target torque is given to the engine controller 45, and the target torque is compared with the actual torque via a limiter 82 (details will be described later). The opening command value of the fuel control valve 32 is obtained by the PID control 83. The fuel control valve 32 is controlled by the controller 45 based on the opening command value, thereby achieving the target torque. The actual torque is detected by the torque sensor 51 (FIG. 1).

  When the target torque is given, the target intake air temperature is selected in consideration of the target intake air temperature map MA, and the heating device 35 is controlled based on the target intake air temperature.

(Application control 1)
In the present embodiment, control (applied control) that is more suitable for actual driving is performed based on the basic control. Hereinafter, this applied control will be described.

  The region Z in which the compression ignition operation of the engine 11 shown in FIG. 3 is possible may slightly vary due to external factors such as the outside air state, the fuel state, and the composition. Therefore, an appropriate combustion state may not be obtained at the target intake air temperature that is uniquely obtained from the given target torque using the target intake air temperature map MA. Therefore, in the present embodiment, the following control is performed as the application control 1.

  In the control logic diagram of FIG. 5, not only the target torque and the actual torque but also the combustion parameter and the combustion parameter target value are input to the engine controller 45. The combustion parameter is calculated by detecting the combustion state in the cylinder 13 with a sensor and using the detected value. Specifically, in the present embodiment, the in-cylinder pressure sensor 49 (FIG. 1) detects the in-cylinder pressure as the combustion state, and the ignition timing in another combustion state is calculated as the combustion parameter from the detected value of the in-cylinder pressure. It is supposed to be.

  This combustion parameter is compared with the combustion parameter target value by the PID control 84, and the target intake air temperature is corrected so that the combustion parameter matches the combustion parameter target value by giving the PID calculation result to the target intake air temperature. It has come to be. For example, when the ignition timing as the combustion parameter is later than the target value, the target intake air temperature is corrected to be higher, and when the ignition timing is earlier than the target value, the target intake air temperature is corrected to be lower.

  That is, in this applied control 1, the target intake air temperature selected from the target torque is not applied as it is, but the target intake air temperature is feedback-controlled by taking into account the actual combustion state, and a more appropriate target intake air temperature. To achieve stable operation.

(Exceptions to Application Control 1)
In the application control 1, the cylinder pressure is detected by the cylinder pressure sensor 49 to obtain the combustion parameter. This detected value is, for example, immediately after the engine 11 is started or when the torque is small when idling. The ratio of noise increases and it is difficult to detect accurately. If the combustion parameter is calculated using an inaccurate detection value and the target intake air temperature is feedback-controlled by the combustion parameter, the operation stability may be hindered.

  Therefore, in this embodiment, when the target torque is less than or equal to a predetermined value, it is assumed that an accurate combustion parameter cannot be obtained, and only the basic control is performed without performing feedback control of the target intake air temperature. When it is equal to or greater than the predetermined value, feedback control of the target intake air temperature (applied control 1) is performed.

  Specifically, as shown in FIG. 5, the PID calculation result of the combustion parameter and the combustion parameter target value is given to the target intake air temperature only when the ON / OFF switch 85 is on. Accordingly, the ON / OFF switch 85 is controlled to be turned on when the target torque is equal to or greater than a predetermined value and to be turned off when the target torque is equal to or smaller than the predetermined value.

  As a result, feedback control is performed only in a region where the combustion state can be accurately detected, and the detection result of the combustion state is appropriately reflected in the control output, thereby realizing stable operation.

(Application control 2)
Next, the second applied control based on the basic control will be described.
In the basic control described above, when a target torque is applied to the engine controller 45, the fuel control valve 32 is controlled so that fuel is supplied immediately according to the target torque. On the other hand, even if the target intake air temperature is selected in consideration of the target intake air temperature map MA from the target torque, if the target intake air temperature is far away from the actual intake air temperature, the mixture becomes the target intake air temperature. There is a time lag until it reaches. During this time lag, the intake air temperature cannot correspond to the target torque and may deviate from the operable region Z shown in FIG.

  For example, as shown in FIG. 6, when the target torque T4 is given while the engine 11 is operating at the torque T3 and the intake air temperature Tm3, the target intake air temperature map MA is considered based on the basic control. A target intake air temperature Tm4 is selected. Then, the engine controller 45 controls the fuel control valve 32 so as to supply fuel according to the target torque T4, and controls the heating device 35 so that the air-fuel mixture reaches the target intake air temperature Tm4. However, since it takes time for the heating device 35 to heat the air-fuel mixture, the torque T4 and the intake air temperature Tm3 correspond to each other (although instantaneously). In this case, the point X corresponding to the torque T4 and the intake air temperature Tm3 is greatly separated upward (knocking side) from the target intake air temperature map MA.

  In order to eliminate such inconvenience, the application control 2 is configured so that the target torque corresponds to the actual intake air temperature when the given target torque deviates from the operable range Z in relation to the actual intake air temperature. By correcting and entering the operation region Z, large fluctuations in the target torque are suppressed and stable operation can be performed.

The application control 2 will be specifically described.
As shown in FIG. 6, the memory of the engine controller 45 stores an allowable maximum target torque map MB and an allowable minimum target torque map MC as in the target intake air temperature map MA. The allowable maximum target torque map MB limits the target torque given to the engine controller 45 to the maximum allowable target torque in consideration of the actual intake air temperature. Similarly, the allowable minimum target torque map MC is limited to the minimum allowable target torque in consideration of the actual intake air temperature.

  As shown in FIG. 6, when the application control 2 is applied in the case where the target torque T4 is applied in the operation state of the torque T3 and the intake air temperature Tm3, the following is obtained. First, when the target torque T4 is given, the target intake air temperature Tm4 is selected in consideration of the target intake air temperature map MA. Then, the heating device 35 (FIG. 1) is controlled so that the air-fuel mixture reaches the target intake air temperature Tm4. On the other hand, the actual intake air temperature detected by the intake air temperature sensor 48 (FIG. 1) does not immediately become Tm4, but is approximately Tm3 immediately after the target torque T4 is given. Therefore, the target torque T4 is corrected to the maximum target torque allowable when the intake air temperature is Tm3, that is, the target torque T5 that intersects with the intake air temperature Tm3 at the point B on the allowable maximum target torque map MB. Then, the controller 45 gives the fuel control valve 32 control according to the target torque T5.

  Since the target intake air temperature is Tm4, the actual intake air temperature gradually decreases from Tm3 to Tm6 and Tm7. On the other hand, as the intake air temperature decreases, the target torque gradually increases to T6 and T4 along the allowable maximum target torque map MB (points C and D). When the target torque reaches T4, the desired target torque is achieved, so that it is constant without further correction, and thereafter, the intake air temperature decreases to Tm4, whereby the torque T4 and the intake air temperature Tm4. Corresponds to the point E on the target intake air temperature map MA. Therefore, the target torque is achieved while maintaining stable operation.

Next, correction of the target torque using the allowable minimum target torque map MC will be described with reference to FIG.
For example, when the engine 11 is operated in the state of the torque T3 ′ and the intake air temperature Tm3 ′, when T4 ′ is given as the target torque, the target intake air temperature Tm4 ′ is selected in consideration of the target intake air temperature map MA. Is done. On the other hand, immediately after the target torque T4 ′ is applied, the intake air temperature is approximately T3 ′. When the operation is performed at the torque T4 ′ and the intake air temperature T3 ′, the operation is performed at the point X ′, and the target intake air temperature map MA is used. Is also far away (misfire side). Therefore, the target torque does not immediately become T4 ′, but is set to T5 ′ corresponding to the actual intake air temperature Tm3 ′ in consideration of the allowable minimum target torque map MC.

  The intake air temperature gradually increases from Tm3 'to Tm6', Tm'7, and accordingly, the target torque gradually decreases to T6 ', T4' along the allowable minimum target torque map MC. Therefore, the point where the target torque corresponds to the intake air temperature changes from point A ′ to point B ′, point C ′, and point D ′. The target torque becomes constant when T4 'is reached, and the intake air temperature decreases to Tm4', so that the torque T4 'and the intake air temperature Tm4' correspond to a point E 'on the target intake air temperature map MA.

  The correction (control) of the target torque as described above is represented as a limiter 82 in the control logic diagram of FIG. That is, the target torque and the intake air temperature (actually, the intake air temperature taking into account the PID calculation result of the combustion parameter and the combustion parameter target value) are input to the limiter 82, and the target torque is corrected.

  As is apparent from FIG. 8 showing the limiter 82 in more detail, the given target torque is compared with the target torque (allowable maximum target torque) obtained from the intake air temperature in consideration of the allowable maximum target torque map MB. When the obtained target torque is larger than the allowable maximum target torque, the allowable maximum target torque is output as a corrected target torque.

  When the target torque is smaller than the allowable maximum target torque, the target torque is compared with the target torque (allowable minimum target torque) obtained by referring to the allowable minimum target torque map MC from the intake air temperature. When the given target torque is smaller than the allowable minimum target torque, the allowable minimum target torque is output as a corrected target torque.

  When the target torque is between the allowable maximum target torque and the allowable minimum target torque, that is, for example, in FIG. 6, the target torque is the allowable maximum target torque map MB and the allowable minimum target torque map MC in relation to the actual intake air temperature. Are output as they are without any correction.

(Exceptions to Application Control 2)
When the engine 11 is stably performing steady operation, stable operation can be continued by performing the application control 2 on the given target torque. However, when the target torque is applied in a state where the intake air temperature has not risen after the engine 11 is started, the following inconvenience may occur when the application control 2 is performed.

  For example, as shown in FIG. 9, after the engine 11 is started, the intake air temperature is still at a low TmA state. When the target torque Tini is first applied in this operation state, the target intake air temperature is determined according to the target intake air temperature map MA. TmB is selected.

  When the application control 2 is applied, the target torque Tini is corrected to the allowable minimum target torque TA selected in consideration of the allowable minimum target torque map MC from the actual intake air temperature TmA. This allowable minimum target torque TA is larger than the target torque Tini, and increases rapidly compared to the actual torque until the target torque is first applied after the start. Such a sudden increase in torque gives a large load to the engine and causes the operation to become extremely unstable.

  Therefore, in the present embodiment, when the target torque Tini is first given after the engine is started, if the target intake air temperature TmB corresponding to the target torque Tini is larger than the actual intake air temperature TmA, the allowable minimum target torque map MC Is going to be ignored.

  In this case, the point X ″ at which the target torque Tini and the actual intake air temperature TmA correspond is far from the target intake air temperature map MA, but the air-fuel mixture is heated and raised by setting the target intake air temperature to TmB. Since it warms, it gradually shifts to stable operation.

[Other Embodiments Regarding the Heating Device 35]
Next, another embodiment of a heating device applicable to the present invention will be described. In addition, in the following description, for convenience, it divides into the following four groups according to the installation location, installation structure, etc. of a heating apparatus, and several embodiment is shown for every group.
(Group 1) Structure in which one heating device is provided in the main intake pipe 27 (Group 2) Structure in which a heating device is provided corresponding to each cylinder 13 (Group 3) A plurality of main intake pipes 27 and / or branch intake pipes 29 Structure in which heating device is provided (Group 4) Structure in which main intake pipe 27 is branched into two paths and a heating apparatus is provided in one path (variation of the first embodiment)

(Group 1) A structure in which one heating device is provided in the main intake pipe 27.
(1-1) FIG. 10 shows an embodiment in which a heating device 35 constituted by an electric heater 53 is provided in the main intake pipe 27. In the case of this embodiment, when the actual intake air temperature is lower than the target intake air temperature, the energization to the electric heater 53 is increased, and when it is higher, the energization to the electric heater 53 is decreased to adjust the intake air temperature. be able to.

  (1-2) FIG. 11 shows an embodiment in which a heating device 35 constituted by a flame burner 54 is provided in the main intake pipe 27. In order to prevent the fuel from directly contacting the flame and burning, only air is circulated through the heating device 35, and the fuel control valve 32 is provided in the branch intake pipe 29 on the downstream side of the heating device 35.

  In this embodiment, when the actual intake air temperature is lower than the target intake air temperature, the amount of fuel supplied to the flame burner 54 is increased, and when the actual intake air temperature is higher, the amount of fuel supplied to the flame burner 54 is decreased. The temperature can be adjusted. Further, the intake air temperature can be rapidly increased as compared with the electric heater 53.

  (1-3) FIG. 12 shows an embodiment in which a heating device 35 constituted by a heat exchanger 40 is provided in the main intake pipe 27. Engine cooling water is supplied to the heat exchanger 40 as a heat exchange medium. The engine cooling water is supplied from the engine main body 11A to the heat exchanger 40 through the flow path 56A, and returned from the heat exchanger 40 to the cooler (not shown) through the flow path 56B. A bypass channel 56C is provided between the channel 56A and the channel 56B. The flow path 56A and the bypass flow path 56C are provided with flow rate adjusting valves 57A and 57C for adjusting the flow rate of the engine cooling water, respectively.

  In this embodiment, when the actual intake air temperature is lower than the target intake air temperature, the flow rate adjusting valves 57A and 57C are adjusted to increase the supply amount of engine cooling water to the heat exchanger 40. The intake air temperature can be adjusted by adjusting the flow rate adjusting valves 57A and 57C to reduce the supply amount of engine cooling water to the heat exchanger 40 (or to zero). Further, since engine cooling water is used as a heat exchange medium, there is no power or fuel consumption compared to the electric heater 53 (FIG. 10) and the flame burner 54 (FIG. 11), and exhaust gas will be described later. There is an advantage that the temperature is stable as compared with the case where gas is used as a heat exchange medium.

  FIG. 29 shows the change in the coolant temperature with the passage of time at the time of engine start (during cold operation). Immediately after startup, the coolant temperature is lower than the target intake air temperature, and after a certain time T1, the coolant temperature becomes higher than the target intake air temperature. In the present embodiment, while the cooling water temperature is lower than the target intake air temperature, the flow rate adjustment valve 57C (FIG. 12) is opened and the flow rate adjustment valve 57A is closed to supply the engine cooling water to the heat exchanger 40. By stopping and closing the flow rate adjustment valve 57C after time T1, and opening the flow rate adjustment valve 57A to supply engine cooling water to the heat exchanger 40, the intake air temperature can be adjusted (increased) efficiently.

  (1-4) FIG. 13 shows an embodiment in which the heating device 35 configured by the heat exchanger 58 is provided in the main intake pipe 27 as in the above (1-3). As the heat exchange medium, engine lubricating oil is used. The engine lubricating oil is supplied from the engine main body 11A to the heat exchanger 35 through the flow path 59A, and is returned from the heat exchanger 35 to the engine main body 11A through the flow path 59B. A bypass channel 59C is provided between the channel 59A and the channel 59B. The flow path 59A and the bypass flow path 59C are respectively provided with flow rate adjusting valves 60A and 60C for adjusting the flow rate of the engine lubricating oil.

  In the case of this example, when the actual intake air temperature is lower than the target intake air temperature, the flow rate adjusting valves 60A and 60C are adjusted to increase the supply amount of engine lubricating oil to the heat exchanger 58. The intake air temperature can be adjusted by adjusting the flow rate adjusting valves 60A and 60C to reduce the amount of engine lubricant supplied to the heat exchanger 58. In the case of this embodiment, since engine lubricating oil is used as a heat exchange medium, there is no consumption of electric power or fuel as compared with the electric heater 53 (FIG. 10) and the flame burner 54 (FIG. 11). As described later, there is an advantage that the temperature is stable as compared with the case where exhaust gas is used as a heat exchange medium. Furthermore, since engine lubricating oil is hotter than engine cooling water, the capacity | capacitance of a heat exchanger can be made small.

  FIG. 29 shows a change in the lubricating oil temperature with the passage of time at the time of engine start (during cold operation). Immediately after startup, the lubricating oil temperature is lower than the target intake air temperature, and after a certain time T2, the lubricating oil temperature becomes higher than the target intake air temperature. In the present embodiment, while the lubricating oil temperature is lower than the target intake air temperature, the flow regulating valve 60C (FIG. 13) is opened and the flow regulating valve 60A is closed to supply the engine lubricating oil to the heat exchanger 40. By stopping and closing the flow rate adjustment valve 60C after time T2 and opening the flow rate adjustment valve 60A to supply lubricating oil to the heat exchanger 40, the intake air temperature can be adjusted (increased) efficiently.

  (1-5) FIG. 14 shows an embodiment in which the heating device 35 configured by the heat exchanger 62 is provided in the main intake pipe 27 as in the above (1-3). As the heat exchange medium, the exhaust gas of the engine 11 is used. The exhaust gas is supplied to the heat exchanger 62 through the flow path 63A branched from the exhaust pipe 26 extending from the exhaust manifold 25, and is discharged to the outside from the flow path 63B. Further, flow rate adjusting valves 64 and 65 are provided in the flow path 63A and the exhaust pipe 26 on the downstream side of the flow path 63A, respectively.

  In the case of the present embodiment, when the actual intake air temperature is lower than the target intake air temperature, the flow rate adjusting valves 64 and 65 are adjusted to increase the supply amount of exhaust gas to the heat exchanger 62. The intake air temperature can be adjusted by adjusting the flow rate adjusting valves 64 and 65 to reduce the amount of exhaust gas supplied to the heat exchanger 62. Further, since exhaust gas is used as a heat exchange medium, there is no consumption of electric power and fuel unlike the electric heater 53 (FIG. 10) and the flame burner 54 (FIG. 11), and further, engine lubricating oil and engine cooling water. Therefore, the intake air temperature can be increased quickly.

(Group 2) Structure in which heating device 35 is provided according to each cylinder 13 (2-1) FIG. 15 shows an embodiment in which a heating device 35 constituted by an electric heater 53 is provided in each branch intake pipe 29. Each electric heater 53 is connected to a temperature controller 67, and the temperature controller 67 adjusts the energization to the electric heater 53 based on the intake air temperature detected by the intake air temperature sensor 48.

  In the case of the present embodiment, the intake air temperature can be adjusted to the target intake air temperature in the same manner as the above-described embodiment (1-1) (FIG. 10), and the same as the above-described embodiment (1-1). There is an effect. Further, the heating device 35 is provided in each branch intake pipe 29 and is controlled via an intake air temperature sensor 48 and a temperature controller 67, respectively, so that the optimum intake air temperature is adjusted for each cylinder. It can be performed.

  In the present embodiment, the temperature controller 67 for each cylinder 13 may be omitted.

  (2-2) FIG. 16 shows an embodiment in which a heating device 35 constituted by a flame burner 54 is provided in each branch intake pipe 29. Further, only air is circulated through the heating device 35 so that the fuel does not directly contact the flame and burn, and the fuel control valve 32 is provided in the branch intake pipe 29 on the downstream side of the heating device 35. Each flame burner 54 is connected to a temperature controller 67, and the temperature controller 67 adjusts the fuel supply amount to the flame burner 54 based on the intake air temperature detected by the intake air temperature sensor 48. .

  In the present embodiment, the intake air temperature can be adjusted to the target intake air temperature in the same manner as the above-described embodiment (1-2) (FIG. 11), and the same effect as the above-described embodiment (1-2). Play. Further, the heating device 35 is provided in each branch intake pipe 29 and is controlled via an intake air temperature sensor 48 and a temperature controller 67, respectively, so that the optimum intake air temperature is adjusted for each cylinder. It can be performed.

  In the present embodiment, the temperature controller 67 for each cylinder 13 may be omitted.

  (2-3) FIG. 17 shows an embodiment in which a heating device 35 configured by the heat exchanger 40 is provided in each branch intake pipe 29. Engine cooling water is supplied to the heat exchanger 40 as a heat exchange medium. The engine cooling water is supplied from the engine main body 11A to each heat exchanger 40 through the flow path 69A, and is returned from the heat exchanger 40 to the cooler (not shown) through the flow path 69B. The flow paths 69A are branched in correspondence with the number of the branch intake pipes 29, and the flow paths 69B extending from the respective branch intake pipes 29 merge together. A flow rate adjusting valve 70 for adjusting the flow rate of the engine coolant is provided in each of the branched flow paths 69A. A bypass channel 69C is provided between the channel 69A and the channel 69B, and a flow rate adjusting valve 57C for adjusting the flow rate of the engine coolant is provided in the bypass channel 69C.

  In the present embodiment, the intake air temperature can be adjusted to the target intake air temperature in the same manner as the above-described embodiment (1-3) (FIG. 12), and the same effect as the above-described embodiment (1-3). Play. Furthermore, since the heating device 35 is provided in each branch intake pipe 29 and the flow rate adjusting valve 70 is provided in each branched flow path 69A, the optimum intake air temperature can be adjusted for each cylinder 13. .

  In the present embodiment, the flow rate adjustment valve 70 of each branched flow path 69A may be omitted.

  (2-4) FIG. 18 shows an embodiment in which the heating device 35 configured by the heat exchanger 58 is provided in each branch intake pipe 29. Engine heat oil is supplied to the heat exchanger 58 as a heat exchange medium. The engine lubricating oil is supplied from the engine main body 11A to each heat exchanger 58 through the flow path 72A, and is returned from the heat exchanger 58 to the engine main body 11A through the flow path 72B. The flow paths 72A are branched in accordance with the number of branch intake pipes 29 in the middle, and the respective flow paths 72B extending from the respective branch intake pipes 29 merge with each other. Each branched flow path 72A is provided with a flow rate adjusting valve 73 for adjusting the flow rate of the engine lubricating oil. A bypass channel 72C is provided between the channel 72A and the channel 72B, and a flow rate adjusting valve 60C for adjusting the flow rate of the engine lubricating oil is provided in the bypass channel 72C.

  In the case of the present embodiment, the intake air temperature can be adjusted to the target intake air temperature in the same manner as the above-described embodiment (1-4) (FIG. 13), and is the same as the above-described embodiment (1-4). The effect of. Further, since the heating device 35 is provided in each branch intake pipe 29 and the flow rate adjusting valve 73 is provided in each branched flow path 72A, the optimum intake air temperature can be adjusted for each cylinder 13. it can.

  In the present embodiment, the flow rate adjustment valve 73 of each branched flow path 72A may be omitted.

  (2-5) The example shown in FIG. 19 shows an embodiment in which the heating device 35 configured by the heat exchanger 62 is provided in each branch intake pipe 29. The heat exchanger 62 is supplied with engine exhaust gas as a heat exchange medium. The exhaust gas is supplied from the exhaust pipe 26 connected to the exhaust manifold 25 to the heat exchanger 62 through a plurality of flow paths 75A branched according to the number of branch intake pipes 29. It is discharged through 75B. Each flow path 75B is connected to the exhaust pipe 26 on the downstream side of the flow path 75A in the exhaust flow direction. A flow rate adjusting valve 76 is provided in each of the branched flow paths 75A, and a flow rate adjusting valve 77 is provided in the exhaust pipe 26 between the flow paths 75A and 75B.

  In the case of the present embodiment, the intake air temperature can be adjusted to the target intake air temperature in the same manner as the above embodiment (1-5), and the same effect as the above embodiment (1-5) can be obtained. . Further, since the heating device 35 is provided in each branch intake pipe 29 and the flow rate adjusting valve 76 is provided in each branched flow path 75A, the optimum intake air temperature can be adjusted for each cylinder 13. it can.

  In the present embodiment, the flow rate adjusting valve 76 of each branched flow path 75A may be omitted.

  (2-6) FIG. 20 shows an embodiment in which the heating device 35 constituted by the glow plug 78 is provided in the engine body 11A (cylinder head 15) in accordance with each cylinder 13. In this embodiment, when the actual intake air temperature is lower than the target intake air temperature, the energization amount to the glow plug 78 is increased, and when the actual intake air temperature is higher, the energization amount to the glow plug 78 is decreased to thereby increase the piston top dead center. The temperature of the nearby mixture can be adjusted. The glow plug 78 has a small capacity compared to the case where the electric heater 53 is used because heat transfer to each cylinder 13 is fast.

(Group 3) Structure in which a plurality of heating devices are provided in the main intake pipe 27 and / or the branch intake pipe 29 (3-1) FIG. 21 shows two heating devices 35 constituted by heat exchangers 40 and 58 as the main intake pipe. 27 shows the embodiment provided in FIG. One heat exchanger (first heat exchanger) 40 is supplied with engine cooling water (first heat exchange medium) as a heat exchange medium, and the other heat exchanger (second heat exchanger) 58 is supplied with an engine. Lubricating oil (second heat exchange medium) is supplied. That is, the present embodiment is a combination of the above-described embodiment (1-3) (FIG. 12) and the above-described embodiment (1-4) (FIG. 13). Therefore, the same reference numerals are given to the same configurations as those of the embodiments, and duplicate descriptions are omitted.

  In the present embodiment, the flow rate adjustment valves 57A, 57C, 60A, and 60C are controlled as follows during cold operation such as when the engine is started. As shown in FIG. 29, when the temperatures of both the engine coolant and the engine lubricating oil are lower than the target intake air temperature (range A), the flow rate adjustment valves 57A and 60A are closed and the flow rate adjustment valves 57C and 60C are closed. Is opened and both supplies to the heat exchangers 40 and 58 are stopped. In a range B in which only the cooling water temperature exceeds the target intake air temperature, the cooling water flow rate adjustment valve 57A is opened and the flow rate adjustment valve 57C is closed to supply the cooling water to the heat exchanger 40. 60A is kept closed and the flow regulating valve 60C is kept open.

  In the range C where both the cooling water and the lubricating oil are higher than the target intake air temperature and the cooling water is higher than the lubricating oil, the low-temperature lubricating oil flow rate adjustment valve 60A is fully opened and the flow rate adjustment valve 60C is fully closed. Then, the flow rate adjusting valves 57A and 57C of the high-temperature cooling water are adjusted according to the target intake air temperature. That is, the low temperature lubricating oil is supplied to the maximum to raise the intake air temperature to a certain level, and the necessary temperature rise is compensated by the high temperature cooling water.

  The lubricating oil becomes hotter than the cooling water at a certain time T3, and in the range D after this time T3, contrary to the above, the flow adjustment valve 57A for the low-temperature cooling water is fully opened and the flow adjustment valve 57C is fully opened. The flow control valves 60A and 60C for the high-temperature lubricating oil are closed and adjusted according to the target intake air temperature.

  By controlling the flow rate adjusting valves 57A, 57C, 60A, and 60C, the intake air temperature can be adjusted (increased) more efficiently by effectively using the temperature difference between the heat exchange media.

  (3-2) FIG. 22 shows an embodiment in which the heating device 35 configured by a heat exchanger is provided in the main intake pipe 27 and each branch intake pipe 29. The heat exchanger (first heat exchanger) 40 provided in the main intake pipe 27 is supplied with engine cooling water (first heat exchange medium) as a heat exchange medium, and each heat exchange provided in each branch intake pipe 29. The engine (second heat exchanger) 58 is supplied with engine lubricating oil (second heat exchange medium). That is, the present embodiment is a combination of the above-described embodiment (1-3) (FIG. 13) and the above-described embodiment (2-4) (FIG. 18). Therefore, the same reference numerals are given to the same configurations as those of the embodiments, and duplicate descriptions are omitted.

  Also in the present embodiment, the respective flow control valves 57A, 57C, 60C, 73 are controlled in the same manner as in the above embodiment (3-1) when the engine is started.

  (3-3) FIG. 23 shows an embodiment in which the heating device 35 configured by the heat exchangers 58 and 40 is provided in the main intake pipe 27 and each branch intake pipe 29. Engine lubricating oil is supplied to the heat exchanger 58 provided in the main intake pipe 27 as a heat exchange medium, and engine cooling water is supplied to the heat exchanger 40 provided in each branch intake pipe 29. That is, this embodiment is a combination of the above embodiment (1-4) (FIG. 13) and the embodiment (2-3) (FIG. 17). Therefore, the same reference numerals are given to the same configurations as those of the embodiments, and duplicate descriptions are omitted.

  Also in the present embodiment, the flow control valves 57C, 70, 60A, and 60C are controlled in the same manner as in the above-described embodiment (3-1) when starting the engine.

  (3-4) FIG. 24 shows an embodiment in which two types of heating devices 35 configured by the heat exchangers 40 and 58 are provided in each branch intake pipe 29. One heat exchanger 40 is supplied with engine cooling water as a heat exchange medium, and the other heat exchanger 58 is supplied with engine lubricating oil. That is, this embodiment is a combination of the above-described embodiment (2-3) (FIG. 17) and the above-described embodiment (2-4) (FIG. 18). Therefore, the same reference numerals are given to the same configurations as those of the embodiments, and duplicate descriptions are omitted.

  Also in the case of this embodiment, the flow control valves 57C, 70, 60C, 73 are controlled in the same manner as in the above embodiment (3-1) when the engine is started.

  Each of the embodiments described in the above (Group 3) combines a heat exchanger that uses engine coolant as a heat exchange medium and a heat exchanger that uses engine lubricant as a heat exchange medium. It is also possible to combine a heat exchanger that is a medium and a heat exchanger that uses engine cooling water or engine lubricating oil as a heat exchange medium. In addition, the plurality of heating devices 35 may be configured by combining the same type or two or more types of electric heaters, flame burners, glow plugs, and heat exchangers.

(Group 4) A structure in which the main intake pipe 27 is branched into two paths and a heating device is provided in one path (modified example of the first embodiment).

  (4-1) In FIG. 25, as in the first embodiment, the main intake pipe 27 is branched into two paths 38 and 39, a heating device 35 is provided in one path 38, and both paths 38 and 39 are adjusted. An embodiment in which the quantity valves 43 and 44 are provided is shown. In the present embodiment, an electric heater 53 is used as the heating device 35. Therefore, the same effect as that of the first embodiment is obtained except that the electric heater 53 is used, and the electric heater 53 as described in the embodiment (1-1) above (FIG. 10). The effect obtained by using is exhibited.

  (4-2) In FIG. 26, as in the first embodiment, the main intake pipe 27 is branched into two paths 38 and 39, a heating device 35 is provided in one path 38, and both paths 38 and 39 are adjusted. An embodiment in which the quantity valves 43 and 44 are provided is shown. In the present embodiment, a flame burner 54 is used as the heating device 35. Therefore, except for the use of the flame burner 54, the same effects as those of the first embodiment can be obtained, and the flame burner 54 as described in the embodiment (1-2) (FIG. 11). The effect obtained by using is exhibited.

  (4-3) In FIG. 27, as in the first embodiment, the main intake pipe 27 is branched into two paths 38 and 39, and a heat exchanger 58 serving as a heating device 35 is provided in one path 38. An embodiment in which metering valves 43 and 44 are provided in the paths 38 and 39 is shown. In this embodiment, engine lubricating oil is used as a heat exchange medium. Accordingly, the same effect as that of the first embodiment is obtained except that the engine lubricant is used, and the engine lubricant as described in the embodiment (1-4) (FIG. 13). The effect obtained by using is exhibited.

  (4-4) FIG. 28 is similar to the first embodiment. The main intake pipe 27 is branched into two paths 38 and 39, and a heat exchanger 62 as a heating device 35 is provided in one path 38. Metering valves 43 and 44 are provided on the paths 38 and 39, respectively. The exhaust pipe 26 is directly connected to the heat exchanger 62. In the present embodiment, exhaust gas is used as a heat exchange medium. Therefore, the same effect as that of the first embodiment is obtained except that exhaust gas is used, and the exhaust gas as described in the above embodiment (1-5) (FIG. 14) is used. The effect obtained by this is produced.

[Other Embodiments]
The present invention is not limited to the above-described embodiment, and can be appropriately modified as follows, for example.

  (1) The premixed compression self-ignition engine of the present invention may be any engine that performs at least a premixed compression self-ignition operation during steady operation, and depends on whether or not the ignition device 37 is used and whether or not the ignition device 37 is used. There are no restrictions.

  (2) The present invention can be applied not only to a premixed compression self-ignition engine but also to a normal spark ignition engine.

  (3) In the above embodiment, the ignition timing is calculated from the detected in-cylinder pressure as the combustion parameter, but other combustion states, for example, knocking strength, misfire rate, combustion mass ratio, etc. can be adopted. .

  (4) In the above embodiment, a four-cylinder premixed compression self-ignition engine is illustrated, but the number of cylinders can be changed as appropriate.

  (5) The premixed compression self-ignition engine of the present invention may perform both the application control 1 and the application control 2 centering on the basic control, or only one of them. Also good.

35 Heating device 13 Cylinder
24 Intake pipe 27 Main intake pipe 29 Branch intake pipe 40 Heat exchanger (for engine coolant)
53 Electric Heater 54 Flame Burner 57 Flow Control Valve 58 Heat Exchanger (For Engine Lubricating Oil)
60 Flow control valve 62 Heat exchanger (for exhaust gas)

Claims (5)

A premixed compression self-ignition engine that burns by compressing and igniting an air-fuel mixture premixed with fuel and air in a combustion chamber in a cylinder at least in steady operation;
A heating device for heating the intake air to the combustion chamber;
The heating device includes a first heat exchanger that uses a first heat exchange medium, and a second heat exchanger that uses a second heat exchange medium different from the first heat exchange medium,
A flow rate adjusting valve for adjusting a supply flow rate of each heat exchange medium to each heat exchanger is provided,
The intake air temperature is adjusted by the heating device so as to set the intake air temperature to a predetermined target value and / or to set a combustion parameter indicating the combustion state in the combustion chamber to a predetermined target value. An engine characterized by being.   The engine according to claim 1, wherein the heating device includes a heat exchanger that uses exhaust gas as a heat exchange medium.   The engine according to claim 1, wherein the heating device includes a heat exchanger that uses engine cooling water as a heat exchange medium.   The engine according to claim 1, wherein the heating device includes a heat exchanger that uses engine lubricating oil as a heat exchange medium. During the cold operation of the engine, the flow rate adjusting valves are controlled so that the supply of the heat exchange medium is started after the temperature of the heat exchange medium becomes higher than the target value of the intake air temperature. And
Further, when both of the first and second heat exchange media are higher than the target value, the flow rate for adjusting the flow rate of the heat exchange medium having the lower temperature among the first and second heat exchange media. The control valve is controlled to be fully opened, and the flow control valve that adjusts the flow rate of the heat exchange medium having a higher temperature is controlled to adjust the flow rate according to the target value. The engine as described in any one of thru | or 4.

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