JP2022035736A - Control device of internal combustion engine - Google Patents

Abstract

To provide a control device of an internal combustion engine capable of further reducing difference between output torque in a single turbo mode and output torque in a twin turbo mode by more simple processing, in controlling the output torque to the target torque in a turbo switching region in which both of the single turbo mode and the twin turbo mode can be applied, in the internal combustion engine having two turbo chargers.SOLUTION: As operation regions of an internal combustion engine, one-turbo region of a single turbo mode, two-turbo regions of a twin turbo mode, and a turbo switching region in which the turbo mode is switched between the one-turbo region and the two-turbo regions, are determined, and in the turbo switching region, an injection amount in the single turbo mode and an injection amount in the twin turbo mode are different from each other to reduce the difference between the output torque in the single turbo mode and the output torque in the twin turbo mode.SELECTED DRAWING: Figure 13

Description

The present invention relates to a control device for an internal combustion engine.

In recent years, internal combustion engines mounted on vehicles, construction machines, and the like include internal combustion engines equipped with a turbocharger that is supercharged using the energy of exhaust gas in order to obtain a larger drive torque. In addition, there is an internal combustion engine equipped with two turbochargers.

For example, an internal combustion engine with two relatively small turbochargers arranged in parallel will have improved response and torque from the low rpm range compared to an internal combustion engine with only one large turbocharger. There are merits such as being able to. However, in an internal combustion engine equipped with two turbochargers, depending on the operating conditions, there is a case of controlling in a single turbo mode in which only one turbocharger is supercharged, and a twin turbo in which two turbochargers are supercharged. It is necessary to switch between the case of controlling by mode and the case of controlling by mode.

For example, as an operating region of an internal combustion engine having two turbochargers, three operating regions of one turbo region, two turbo regions, and a turbo switching region are set. The 1 turbo region is an operating region controlled in the single turbo mode in which the load of the internal combustion engine is relatively small (the exhaust flow rate is relatively small). The 2 turbo region is an operating region controlled in the twin turbo mode in which the load of the internal combustion engine is relatively large (exhaust flow rate is relatively large). The turbo switching region is an region between the 1 turbo region and the 2 turbo region, and is an operating region in which switching from the single turbo mode to the twin turbo mode or from the twin turbo mode to the single turbo mode occurs. In the internal combustion engine, a target torque is set according to the operating condition in the operating region, and the fuel injection amount is set so that the output torque according to the operating condition approaches the target torque (so that the target torque is reached). Be controlled.

When the operating state of the internal combustion engine is within one turbo region, the single turbo mode is set and the twin turbo mode is not switched, so that the injection amount of the fuel that generates the target torque is determined to be one value. Similarly, when the operating state of the internal combustion engine is within the two turbo region, the twin turbo mode is set and the mode is not switched to the single turbo mode, so that the injection amount of the fuel that generates the target torque is determined to be one value. However, when the operating state of the internal combustion engine is within the turbo switching region, the injection amount of the fuel that generates the target torque is the injection amount when controlled in the single turbo mode and the injection amount when controlled in the twin turbo mode. The injection amount is different from that of.

In the case of the twin turbo mode, the exhaust is divided and flowed to two turbochargers arranged in parallel, so compared to the case of the single turbo mode where all the exhaust is flowed to one turbocharger, the exhaust is exhausted. Less pressure loss (less so-called pumping loss). Therefore, even if the same amount of fuel is injected, the output torque of the internal combustion engine is larger in the twin turbo mode than in the single turbo mode. If you switch from single turbo mode to twin turbo mode or from twin turbo mode to single turbo mode without considering this point, torque fluctuations may occur and a level of shock that the user can clearly experience may occur. Therefore, it is not preferable.

For example, Patent Document 1 discloses an engine control device capable of estimating the shaft torque generated by an engine without directly detecting the pressure in the combustion chamber of the engine with a pressure sensor. The control device described in Patent Document 1 has a combustion mass and combustion at a crank angle during combustion of gas in a combustion chamber based on an operating state which is a heat generation start timing (or a combustion period from the start of combustion to a predetermined crank angle). Estimate one of the combustion mass ratio and heat generation pattern at the crank angle during combustion of gas in the room, estimate the shaft torque generated by the engine based on the estimated one value, and set the ignition timing. It is controlled to suppress sudden changes in torque.

Japanese Unexamined Patent Publication No. 2005-330931

In Patent Document 1, the pressure in the combustion chamber of the engine is not directly detected by the pressure sensor, but the detection of the heat generation start time (or combustion period) and either the combustion mass or the combustion mass ratio or the heat generation pattern. It is not very preferable because the process of estimating one and estimating the shaft torque generated by the engine based on any one of the estimated values is complicated, the amount of processing is large, and the load on the control device is large. ..

The present invention was devised in view of such a point, and in an internal combustion engine having two turbochargers, the output torque is in the turbo switching region where both modes of single turbo mode and twin turbo mode are possible. When controlling to the target torque, the difference between the output torque in the single turbo mode and the output torque in the twin turbo mode can be further reduced by a simpler process. An object is to provide a control device.

In order to solve the above problems, the first invention of the present invention detects the operating state of an internal combustion engine having a first turbocharger and a second turbocharger, and based on the detected operating state, the cylinder of the internal combustion engine. A single turbo mode in which the injection amount of fuel injected into the engine is controlled and supercharged using only the first turbocharger, and a twin turbo mode in which supercharging is performed using both the first turbocharger and the second turbocharger. It is a control device for an internal combustion engine that switches between. In the control device, as the operating region of the internal combustion engine, a 1 turbo region which is the operating region controlled in the single turbo mode, a 2 turbo region which is the operating region controlled in the twin turbo mode, and the above 1 A turbo switching region which is an operating region set between the turbo region and the two turbo regions and where switching from the single turbo mode to the twin turbo mode or switching from the twin turbo mode to the single turbo mode occurs. , Is set. Then, the control device obtains the target torque of the internal combustion engine based on the operating state, and when obtaining the injection amount so that the output torque of the internal combustion engine approaches the target torque, based on the operating state. When the determined operating region is the turbo switching region, the output torque of the internal combustion engine when controlled in the single turbo mode and the output torque of the internal combustion engine when controlled in the twin turbo mode Switching region injection amount for obtaining the injection amount so that the injection amount when controlled in the single turbo mode and the injection amount when controlled in the twin turbo mode are different so that the difference becomes small. It is a control device for an internal combustion engine having an adjusting unit.

Next, the second invention of the present invention is the control device of the internal combustion engine according to the first invention, and the control device includes the two turbos from the one turbo region via the turbo switching region. An allowable upper limit injection amount, which is an upper limit amount of the allowable injection amount, is set across the region. Then, when the operating region determined based on the operating state by the switching region injection amount adjusting unit is the turbo switching region, the control device has the same as the injection amount when controlled in the single turbo mode. The allowable upper limit injection amount is set to a value larger than the allowable upper limit injection amount and the allowable upper limit injection amount when controlled in the twin turbo mode, or is determined by the switching region injection amount adjusting unit based on the operating state. When the operating region is the turbo switching region, the switching region injection amount adjusting unit controls the injection amount and the allowable upper limit injection amount when controlled in the twin turbo mode in the single turbo mode. This is an internal combustion engine control device having a value smaller than the injection amount and the allowable upper limit injection amount in the case.

Next, the third invention of the present invention is the control device for the internal combustion engine according to the second invention, in which the operating region determined based on the operating state is the turbo switching region. In some cases, one turbo pumping loss, which is the loss of kinetic energy used for intake and exhaust of the internal combustion engine when controlled in the single turbo mode, and the pumping loss during one turbo, and the internal combustion engine when controlled in the twin turbo mode. The pumping loss at 2 turbos, which is the loss of kinetic energy used for intake and exhaust, is estimated, and the pumping loss difference, which is the difference between the estimated pumping loss at 1 turbo and the pumping loss at 2 turbos, is obtained. , Has a pumping loss estimation unit. Then, when the operating region determined based on the operating state by the switching region injection amount adjusting unit is the turbo switching region, the control device adjusts the turbo mode adjusting injection amount based on the pumping loss difference. The turbo mode adjusted injection amount is obtained with respect to the injection amount and the allowable upper limit injection amount when controlled in the single turbo mode, and the injection amount and the allowable upper limit injection amount when controlled in the twin turbo mode. When the operating region determined based on the operating state by the switching region injection amount adjusting unit is the turbo switching region, the turbo mode adjusted injection amount is increased based on the pumping loss difference. The turbo mode adjusted injection amount is obtained with respect to the injection amount and the allowable upper limit injection amount when controlled in the twin turbo mode, and the injection amount and the allowable upper limit injection amount when controlled in the single turbo mode. It is a control device for an internal combustion engine that reduces the weight only.

Next, a fourth aspect of the present invention is the internal combustion engine control device according to the third aspect of the present invention, wherein the operating region determined based on the operating state is the turbo switching region. In one case, the total loss at 1 turbo, which is the energy loss including the cooling loss at 1 turbo, which is the loss of heat energy of the internal combustion engine when controlled in the single turbo mode, and the pumping loss at 1 turbo, and the twin. The estimated 2 turbo cooling loss, which is the heat energy loss of the internal combustion engine when controlled in the turbo mode, and the 2 turbo total loss, which is the energy loss including the 2 turbo pumping loss, are estimated. It has a total loss estimation unit that obtains a total loss difference, which is the difference between the total loss at 1 turbo and the total loss at 2 turbos. Then, when the operating region determined based on the operating state by the switching region injection amount adjusting unit is the turbo switching region, the control device has the turbo mode adjusted injection amount based on the total loss difference. It is a control device for an internal combustion engine.

According to the first invention, when the operating region determined based on the operating state of the internal combustion engine is the turbo switching region, the output torque when controlled in the single turbo mode and the output torque when controlled in the twin turbo mode. The injection amount is obtained so that the fuel injection amount in the single turbo mode and the fuel injection amount in the twin turbo mode are different values so that the difference between the two and the fuel injection amount becomes small. As a result, in an internal combustion engine having two turbochargers, simpler processing is performed when controlling the output torque to be the target torque in the turbo switching region where both modes, single turbo mode and twin turbo mode, are possible. Can be. Further, by this simple processing, the difference between the output torque in the single turbo mode and the output torque in the twin turbo mode can be further reduced.

As described above, the output torque of the internal combustion engine is larger in the twin turbo mode than in the single turbo mode even if the injection amount of the fuel is the same in the same operating state. According to the second invention, in the turbo switching region where both the single turbo mode and the twin turbo mode are possible, the injection amount and the allowable upper limit injection amount in the single turbo mode are set as the injection amount in the twin turbo mode. The value shall be larger than the allowable upper limit injection amount. Alternatively, the injection amount and the allowable upper limit injection amount in the twin turbo mode are set to be smaller than the injection amount and the allowable upper limit injection amount in the single turbo mode. As a result, the difference between the output torque in the single turbo mode and the output torque in the twin turbo mode can be further reduced by a simpler process.

According to the third invention, the pumping loss at 1 turbo when controlled in the single turbo mode and the pumping loss at 2 turbo when controlled in the twin turbo mode are estimated, the pumping loss difference is obtained, and the pumping loss difference is obtained. The turbo mode adjustment injection amount is obtained based on. As a result, an appropriate correction amount (turbo mode adjustment injection amount) that can further reduce the difference between the output torque in the single turbo mode and the output torque in the twin turbo mode is obtained by a simpler process. be able to.

According to the fourth invention, the turbo mode adjusted injection amount is based on the total loss difference obtained by adding the difference in thermal energy to the pumping loss difference which is the difference in kinetic energy between the single turbo mode and the twin turbo mode. Ask for. Thereby, an appropriate correction amount (turbo mode adjustment injection amount) that can further reduce the difference between the output torque in the single turbo mode and the output torque in the twin turbo mode can be obtained.

It is a figure explaining the example of the internal combustion engine system which has the control device of the internal combustion engine of this invention. It is a figure explaining the intake path and the exhaust path in the case of the single turbo mode in the internal combustion engine system shown in FIG. 1. It is a figure explaining the intake path and the exhaust path in the twin turbo mode in the internal combustion engine system shown in FIG. 1. It is a figure explaining the difference of the output torque of the internal combustion engine in the case of a single turbo mode and the case of a twin turbo mode. It is a figure explaining the example which divided the operation area of an internal combustion engine into 1 turbo area, turbo switching area, and 2 turbo areas. It is a figure explaining the example which set the target torque with respect to the operation area shown in FIG. It is a figure explaining the example which set the fuel injection amount so that the output torque becomes a target torque with respect to the target torque shown in FIG. It is a figure explaining the example which set the permissible upper limit injection amount with respect to the fuel injection amount shown in FIG. 7. FIG. 8 is a diagram illustrating an example in which the fuel injection amount in the twin turbo mode is adopted in the turbo switching region for the fuel injection amount, and the allowable upper limit injection amount in the twin turbo mode is adopted for the allowable upper limit injection amount. .. In contrast to the example shown in FIG. 7, it is a figure explaining an example in which the torque in the 2 turbo region becomes the torque characteristic TQ20 when the fuel injection amount is set along the characteristic G11 of the fuel injection amount in the 2 turbo region. It is a flowchart explaining the example of the processing procedure of a control device. It is a flowchart explaining the detail of the process SA000 in the flowchart shown in FIG. It is a flowchart explaining the detail of the process SB000 in the flowchart shown in FIG. It is a figure explaining the example which gradually reduces the final injection amount and the final permissible upper limit injection amount at the time of switching from a single turbo mode to a twin turbo mode in a turbo switching region. It is a figure explaining the example which gradually increases the final injection amount and the final permissible upper limit injection amount at the time of switching from a twin turbo mode to a single turbo mode in a turbo switching region. In other embodiments, with respect to FIG. 9, the fuel injection amount in the single turbo mode is adopted in the turbo switching region for the fuel injection amount, and the allowable upper limit injection amount in the single turbo mode is adopted for the allowable upper limit injection amount. It is a figure explaining an example. In another embodiment, it is a flowchart explaining the change part from the process SB000 shown in FIG.

● [Example of configuration of internal combustion engine system 1 (Fig. 1)]
Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. First, an example of the configuration of the internal combustion engine system 1 mounted on the vehicle will be described with reference to FIG. In the description of the present embodiment, an internal combustion engine 10 (for example, a diesel engine) mounted on a vehicle will be used as an example of the internal combustion engine. Further, the internal combustion engine system 1 shown in FIG. 1 has a supercharging system 30 having a first turbocharger 31 and a second turbocharger 32.

Hereinafter, the internal combustion engine system 1 will be described in order from the intake side (upper part of FIG. 1) to the exhaust side (lower part of FIG. 1) with reference to FIG. On the inflow side of the intake pipe 11A, an intake flow rate detecting means 21 (for example, an intake flow rate sensor), an atmospheric pressure detecting means 22D (for example, a pressure sensor), and an intake air temperature detecting means 22E (for example, a temperature sensor) are provided. There is. The intake flow rate detecting means 21 outputs a detection signal according to the flow rate of the air sucked by the internal combustion engine 10 to the control device 70. The atmospheric pressure detecting means 22D outputs a detection signal corresponding to the atmospheric pressure (atmospheric pressure) of the atmosphere to the control device 70, and the intake air temperature detecting means 22E sets the temperature of the air sucked by the internal combustion engine 10 (outside air temperature). The corresponding detection signal is output to the control device 70. The outflow side of the intake pipe 11A is bifurcated into the first intake inflow passage 11B1 and the second intake inflow passage 11B2, and is divided into the inflow side of the first intake inflow passage 11B1 and the inflow side of the second intake inflow passage 11B2. It is connected.

The outflow side of the first intake inflow passage 11B1 is connected to the intake inflow port of the first compressor 31A of the first turbocharger 31. Further, the outflow side of the intake bypass passage 11CB is connected in the middle of the first intake inflow passage 11B1. The intake / discharge port of the first compressor 31A is connected to the inflow side of the first intake / discharge passage 11C1, and the outflow side of the first intake / discharge passage 11C1 is connected to the outflow side of the second intake / discharge passage 11C2 and the final intake point PA3. It is merged and connected to the inflow side of the merged intake passage 11D. The first compressor 31A is rotationally driven by the first turbine 31B, compresses the air sucked from the first intake inflow passage 11B1 and discharges it to the first intake / discharge passage 11C1.

The outflow side of the second intake inflow passage 11B2 is connected to the intake inflow port of the second compressor 32A of the second turbocharger 32. The intake / discharge port of the second compressor 32A is connected to the inflow side of the second intake / discharge passage 11C2, and the outflow side of the second intake / discharge passage 11C2 is connected to the outflow side of the first intake / discharge passage 11C1 and the final intake point PA3. It is merged and connected to the inflow side of the merged intake passage 11D. The second compressor 32A is rotationally driven by the second turbine 32B, compresses the air sucked from the second intake inflow passage 11B2, and discharges it to the second intake / discharge passage 11C2. The intake bypass passage 11CB is branched from the intake branch point PA1 of the second intake / discharge passage 11C2 and connected to the intake intermediate confluence point PA2 of the first intake inflow passage 11B1.

The intake switching valve 62 is provided on the intake downstream side of the intake branch point PA1 which is a branch point with the intake bypass passage 11CB in the second intake / discharge passage 11C2, and the second intake is based on the control signal from the control device 70. The discharge passage 11C2 is opened and closed. Further, the intake bypass valve 61 is provided in the intake bypass passage 11CB, and opens and closes the intake bypass passage 11CB based on the control signal from the control device 70. A boost pressure detecting means 22G is provided between the intake branch point PA1 and the intake switching valve 62 in the second intake / discharge passage 11C2. The boost pressure detecting means 22G is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure of the intake air in the second intake air discharge passage 11C2 at the position where it is provided to the control device 70.

The inflow side of the merging intake passage 11D is connected to the outflow side of the first intake / discharge passage 11C1 and the outflow side of the second intake / discharge passage 11C2, and the outflow side of the merging intake passage 11D is connected to the inflow side of the intake manifold 11E. Has been done. Further, the merging intake passage 11D is provided with a boost pressure detecting means 22F, an intercooler 38, a throttle device 33 controlled by the control device 70, and the like. The boost pressure detecting means 22F is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure of the intake air in the merging intake passage 11D to the control device 70.

Further, the outflow side of the EGR passage 13A is connected to the merging intake passage 11D. The inflow side of the EGR passage 13A is connected to the exhaust manifold 12A2. The EGR passage 13A is provided with an EGR cooler 34 and an EGR valve 35 controlled by the control device 70.

The intake manifold 11E includes a boost pressure detecting means 22A (for example, a pressure sensor) in the intake manifold that detects the boost pressure in the intake manifold 11E, and an intake temperature detection in the intake manifold that detects the intake temperature in the intake manifold 11E. Means 28A (eg, a temperature sensor) is provided. The supercharged pressure detecting means 22A in the intake manifold 11E outputs a detection signal corresponding to the pressure of the intake air (supercharged intake air) in the intake manifold 11E to the control device 70. The intake air temperature detecting means 28A in the intake intake manifold outputs a detection signal corresponding to the temperature of the intake air in the intake intake manifold 11E to the control device 70.

The outflow side of the intake manifold 11E is connected to each cylinder of the internal combustion engine 10.

The internal combustion engine 10 has a plurality of cylinders, and injectors 43A to 43H are provided in each cylinder. Fuel is supplied to the injectors 43A to 43H from the common rail 42 via the fuel pipe, and the injectors 43A to 43H are driven by a control signal from the control device 70 to inject fuel into the respective cylinders.

Fuel is supplied to the common rail 42 from a fuel pressure adjusting pump 41 driven based on a control signal from the control device 70. Further, the common rail 42 is provided with a fuel pressure detecting means 23 (for example, a pressure sensor) for detecting the pressure of the fuel in the common rail 42. The fuel pressure detecting means 23 outputs a detection signal corresponding to the detected fuel pressure to the control device 70. The control device 70 controls the fuel pressure adjusting pump 41 so that the fuel pressure based on the detection signal from the fuel pressure detecting means 23 becomes the target fuel pressure.

The internal combustion engine 10 is provided with a crank angle detecting means 25A (for example, a rotation sensor), a cam angle detecting means 25B (for example, a rotation sensor), a coolant temperature detecting means 24 (for example, a temperature sensor), and the like. The crank angle detecting means 25A outputs a detection signal corresponding to the rotation angle of the crankshaft of the internal combustion engine 10 to the control device 70. The control device 70 detects the rotation speed of the internal combustion engine 10 based on the detection signal from the crank angle detecting means 25A. The cam angle detecting means 25B outputs a detection signal corresponding to the rotation angle of the camshaft of the internal combustion engine 10 to the control device 70. The coolant temperature detecting means 24 outputs a detection signal according to the temperature of the cooling coolant circulating in the internal combustion engine 10 to the control device 70.

The inflow side of the exhaust manifolds 12A1 and 12A2 is connected to the exhaust side of the internal combustion engine 10, the inflow side of the first exhaust inflow passage 12B1 is connected to the outflow side of the exhaust manifold 12A1, and the second exhaust is connected to the outflow side of the exhaust manifold 12A2. The inflow side of the inflow passage 12B2 is connected. The outflow side of the first exhaust inflow passage 12B1 is connected to the exhaust inlet of the first turbine 31B, and the outflow side of the second exhaust inflow passage 12B2 is connected to the exhaust inlet of the second turbine 32B. Further, the inflow side of the first exhaust inflow passage 12B1 and the inflow side of the second exhaust inflow passage 12B2 are communicated with each other by the exhaust communication passage 12BB.

The inflow side of the first exhaust discharge passage 12C1 is connected to the exhaust discharge port of the first turbine 31B, and the outflow side of the first exhaust discharge passage 12C1 is connected to the outflow side of the second exhaust discharge passage 12C2 and the final exhaust confluence point PB3. It is merged and connected to the inflow side of the merged exhaust passage 12D. The inflow side of the second exhaust discharge passage 12C2 is connected to the exhaust discharge port of the second turbine 32B, and the outflow side of the second exhaust discharge passage 12C2 is connected to the outflow side of the first exhaust discharge passage 12C1 and the final exhaust confluence point PB3. It is merged and connected to the inflow side of the merged exhaust passage 12D. The outflow side of the merging / exhaust passage 12D is connected to the inflow side of the oxidation catalyst 51.

The exhaust switching valve 63 is provided on the exhaust downstream side of the second exhaust inflow passage 12B2 at the connection point with the exhaust communication passage 12BB. The exhaust switching valve 63 opens and closes the second exhaust inflow passage 12B2 based on the control signal from the control device 70.

Further, in the first exhaust discharge passage 12C1, an exhaust pressure detecting means 22B (for example, a pressure sensor) for detecting the pressure of the exhaust in the first exhaust discharge passage 12C1 and an exhaust for detecting the temperature of the exhaust in the first exhaust discharge passage 12C1. A temperature detecting means 26 (for example, a temperature sensor) and the like are provided. The exhaust pressure detecting means 22B outputs a detection signal corresponding to the detected pressure to the control device 70, and the exhaust temperature detecting means 26 outputs a detection signal corresponding to the detected temperature to the control device 70.

The first turbine 31B is exhausted by adjusting the opening degree (closedness) of the flow path in the first turbine, which is the flow path of the exhaust gas guided from the exhaust inlet of the first turbine 31B to the first turbine 31B. A plurality of first variable nozzles 31C capable of adjusting the flow velocity of the above are provided. The first variable nozzle 31C is operated by a nozzle driving means 31D (for example, an electric motor) that operates in response to a control signal from the control device 70. Further, the nozzle opening degree detecting means 31E (for example, a rotation angle sensor) controls a detection signal according to the operating state of the nozzle driving means 31D (in this case, the rotation angle of the electric motor) according to the opening degree of the first variable nozzle 31C. Output to the device 70. The same applies to the second variable nozzle 32C, the nozzle driving means 32D, and the nozzle opening detection means 32E that adjust the opening degree (closedness) of the flow path in the second turbine, and thus the description thereof will be omitted.

The outflow side of the oxidation catalyst 51 is connected to the inflow side of the DPF 52 (fine particle collection filter). The oxidation catalyst 51 oxidizes and purifies HC (hydrocarbon) and CO (carbon monoxide) in the exhaust gas of the internal combustion engine 10.

The outflow side of the DPF 52 is connected to the inflow side of the urea SCR53, and the DPF 52 collects fine particles in the exhaust gas. Further, the DPF 52 is provided with a differential pressure detecting means 22C (for example, a differential pressure sensor) for detecting the pressure difference between the inflow side and the outflow side of the DPF 52. The differential pressure detecting means 22C outputs a detection signal corresponding to the pressure difference between the inflow side and the outflow side of the DPF 52 to the control device 70. The control device 70 can estimate the amount of fine particles deposited on the DPF 52 from the differential pressure based on the detection signal from the differential pressure detecting means 22C.

The urea SCR53 uses urea injected from a urea water addition valve (not shown) to reduce and purify NOx (nitrogen oxide) in the exhaust gas.

The accelerator pedal depression amount detecting means 27 (for example, an accelerator pedal depression angle sensor) is provided on the accelerator pedal, and outputs a detection signal according to the depression amount of the accelerator pedal by the driver to the control device 70.

The control device 70 includes a CPU 71, a RAM 72, a storage means 73, an EEPROM 74, a timer 75, and the like. The RAM 72, the storage means 73, the EEPROM 74, the timer 75, and the like are connected to the CPU 71 by various buses. The storage means 73 is, for example, a storage device such as a Flash ROM, and stores programs, data, and the like for executing a process described later. Further, the CPU 71 has a switching region injection amount adjusting unit 71A, a pumping loss estimation unit 71B, a total loss estimation unit 71C and the like, which will be described later, and details of these will be described later.

● [Differences in intake path and exhaust path and difference in output torque between single turbo mode and twin turbo mode (Figs. 2 to 4)]
FIG. 2 shows an intake path (thick solid line in FIG. 2) and an exhaust path (in FIG. 2) in the single turbo mode in which only the first turbocharger 31 is used in the internal combustion engine system 1 shown in FIG. Thick dotted line) is shown. In the single turbo mode, the intake bypass valve 61, the intake switching valve 62, and the exhaust switching valve 63 are controlled to the closed side from the control device 70. Further, FIG. 3 shows an intake path (thick solid line in FIG. 3) in the twin turbo mode in which the internal combustion engine system 1 shown in FIG. 1 is supercharged using both the first turbocharger 31 and the second turbocharger 32. The exhaust path (thick dotted line in FIG. 3) is shown. In the twin turbo mode, the intake bypass valve 61 is controlled from the control device 70 to the closing side, and the intake switching valve 62 and the exhaust switching valve 63 are controlled to the opening side from the control device 70.

In the exhaust path in the single turbo mode shown in FIG. 2, the exhaust from both the exhaust manifolds 12A1 and 12A2 is the first exhaust inflow passage 12B1 as compared with the exhaust path in the twin turbo mode shown in FIG. It is summarized in. Therefore, the pressure of the exhaust gas in the exhaust manifolds 12A1 and 12A2 in the single turbo mode shown in FIG. 2 is higher than the pressure of the exhaust gas in the exhaust manifolds 12A1 and 12A2 in the twin turbo mode shown in FIG. In other words, in the exhaust path in the twin turbo mode shown in FIG. 3, the exhaust from the exhaust manifolds 12A1 and 12A2 is different from the exhaust path in the single turbo mode shown in FIG. , The flow is dispersed in each of the first exhaust inflow passage 12B1 and the second exhaust inflow passage 12B2. Therefore, the pressure of the exhaust gas in the exhaust manifolds 12A1 and 12A2 in the twin turbo mode shown in FIG. 3 is lower than the pressure of the exhaust gas in the exhaust manifolds 12A1 and 12A2 in the single turbo mode shown in FIG.

As described above, as shown in FIG. 4, even if the fuel injection amount is the same in the same operating state, the pumping loss SP1 at 1 turbo, which is the pumping loss in the single turbo mode, is the pumping loss in the twin turbo mode. It becomes larger than a certain 2 turbo pumping loss SP2.

The pumping loss in FIG. 4 is a loss of kinetic energy used for intake and exhaust of the internal combustion engine 10. Further, the other loss in FIG. 4 is a loss including a cooling loss which is a loss of heat energy of the internal combustion engine 10, and also includes an exhaust loss and a mechanical loss. In the case of the single turbo mode, the loss including the pumping loss SP1 at 1 turbo and the other loss SR1 at 1 turbo including the cooling loss is defined as the total loss SS1 at 1 turbo. Further, in the twin turbo mode, the loss including the pumping loss SP2 at the time of 2 turbos and the other loss SR2 at the time of 2 turbos including the cooling loss is defined as the total loss SS2 at the time of 2 turbos. The pumping loss SP1 at 1 turbo is larger than the pumping loss SP2 at 2 turbos, and the total loss SS1 at 1 turbo is larger than the total loss SS2 at 2 turbos. Therefore, even if the fuel injection amount is the same, the output torque TQ2 at 2 turbo, which is the output torque of the internal combustion engine 10 in the twin turbo mode, is the output torque of the internal combustion engine 10 at 1 turbo in the single turbo mode. It becomes larger than the output torque TQ1.

● [Setting of operating area of internal combustion engine, target torque, fuel injection amount, allowable upper limit injection amount (Figs. 5 to 10)]
FIG. 5 shows an example of an operating region based on the operating state of the internal combustion engine 10. The storage means of the control device 70 is set with an operating area according to the operating state of the internal combustion engine 10. For example, as shown in FIG. 5, the operating region is set to three regions according to the rotation speed of the internal combustion engine 10. The region where the rotation speed is lower than the first rotation speed N1 is set to one turbo region which is an operation region controlled in the single turbo mode. The region where the rotation speed is the second rotation speed N2 or more is set to the two turbo region which is the operation region controlled in the twin turbo mode. In the region where the rotation speed is N1 or more and less than the second rotation speed N2 (the region between the 1 turbo region and the 2 turbo region), the single turbo mode is switched to the twin turbo mode, or the twin turbo mode is used. It is set in the turbo switching area, which is the operating area where switching to the single turbo mode occurs. In the following description, an example in which the operating area is divided according to the rotation speed will be described, but the operation area may be divided according to the exhaust flow rate, the boost pressure, and the like without being limited to the rotation speed.

In FIG. 6, the target torque TgTQ set based on the durability of the internal combustion engine 10 and the target kinetic performance of the vehicle equipped with the internal combustion engine 10 with respect to the operating region shown in FIG. 5 is the rotation speed of the internal combustion engine. An example of setting according to (according to the operating area) is shown.

FIG. 7 shows an example in which the fuel injection amount is set so that the output torque of the internal combustion engine 10 becomes the target torque shown in FIG. 6 with respect to the operating region shown in FIG. As described above, even if the fuel injection amount is the same, the output torque in the twin turbo mode is larger than the output torque in the single turbo mode. Therefore, in the case of the single turbo mode, the fuel injection amount of the characteristic G1 is shown, and in the case of the twin turbo mode, the fuel injection amount of the characteristic G2 is shown. Even if the number of revolutions is the same, the fuel injection amount (and target torque) differs depending on the operating condition such as when traveling on flat ground, climbing a slope, descending a slope, etc., so here, an example in the case of a certain operating condition A. It is explained as. The difference ΔQ between the characteristic G1 and the characteristic G2 of the fuel injection amount is the fuel injection amount based on the above-mentioned total loss difference, and corresponds to the turbo mode adjustment injection amount described later.

FIG. 8 shows an example in which an allowable upper limit injection amount is set with respect to the fuel injection amount shown in FIG. As the allowable upper limit injection amount, the upper limit fuel injection amount based on the output torque, durability, etc. of the internal combustion engine 10 is set. The allowable upper limit injection amount is the characteristic LM1 in the case of the single turbo mode and the characteristic G2 which is the fuel injection amount in the twin turbo mode with respect to the characteristic G1 which is the fuel injection amount in the single turbo mode, in the case of the twin turbo mode. The characteristic LM2 of is set.

There are two types of fuel injection amount characteristics G1 and G2 shown in FIG. 8 in the turbo switching region, and in order to obtain the characteristic G3 of one fuel injection amount, as shown in FIG. 9, the characteristics G1 and G2 in one turbo region. In the turbo switching region and the 2 turbo region, the characteristic G2 and the characteristic G3 are used as the (provisional) fuel injection amount. Similarly, there are two types of the characteristic LM1 and LM2 of the allowable upper limit injection amount shown in FIG. 8 in the turbo switching region, and one turbo is used as shown in FIG. 9 in order to obtain the characteristic LM3 of one allowable upper limit injection amount. The characteristic LM3 having the characteristic LM1 in the region and the characteristic LM2 in the turbo switching region and the 2 turbo region is set as the (provisional) allowable upper limit injection amount. In the flowchart described below, the fuel injection amount is first calculated based on the characteristic G3 which is the (provisional) fuel injection amount, and then corrected (adjusted) in the case of the single turbo mode or the like. Similarly, the allowable upper limit injection amount is first calculated based on the characteristic LM3 which is the (provisional) allowable upper limit injection amount, and then corrected (adjusted) in the case of the single turbo mode or the like. The allowable upper limit injection amount (characteristic LM3) is set as the upper limit amount of the allowable fuel injection amount from the 1 turbo region to the 2 turbo regions via the turbo switching region.

As shown in FIG. 10 illustrated for comparison, when the fuel injection amount is the characteristic G1 in the 1 turbo region and the turbo switching region and the characteristic G11 which is an extension of the characteristic G1 in the 2 turbo region, the fuel injection amount is controlled in the single turbo mode. Since a step ΔTQ is generated between the characteristic TQ10 in the case of the above and the characteristic TQ20 in the case of controlling in the twin turbo mode, the characteristic G11 in which the fuel injection amount is continuous without a step is not preferable.

● [Processing procedure of control device 70 (FIG. 11)]
Next, an example of the processing procedure of the control device 70 (CPU71) will be described with reference to the flowchart shown in FIG. The process shown in FIG. 11 is started, for example, at predetermined time intervals (for example, intervals of several [ms] to several tens [ms]), and when started, the control device 70 (CPU71) proceeds to step S010. ..

In step S010, the control device 70 detects the operating state of the internal combustion engine 10 based on the detection signals from the various detection means described above, the control signals of the various actuators, and the like. The operating state includes the number of revolutions of the internal combustion engine, the amount of depression of the accelerator pedal, the amount of fuel injection, and the like. Then, the control device 70 obtains a target torque based on the operating state, and proceeds to step S015. For example, the control device 70 obtains a target torque based on the rotation speed of the internal combustion engine, the fuel injection amount, the accelerator pedal depression amount, and the like.

In step S015, the control device 70 determines the operating area based on the operating state, and proceeds to step S020. For example, the control device 70 determines which of the 1 turbo region, the turbo switching region, and the 2 turbo region shown in FIG. 5 is the operating region based on the rotation speed of the internal combustion engine, and stores the determined operating region. ..

In step S020, the control device 70 determines whether to control in the single turbo mode or the twin turbo mode based on the operating area and the operating state. For example, the control device 70 determines that the control is performed in the single turbo mode when the operating region is the 1 turbo region, and determines that the control is performed in the twin turbo mode when the operating region is the 2 turbo region. If the operating area is the turbo switching area, it is determined whether to control in the single turbo mode or the twin turbo mode based on the switching conditions and the operating state set in advance, and if necessary. The turbo mode switching control is executed, and the process proceeds to step S025.

In the turbo mode switching control, the control device 70 is currently switching from the single turbo mode to the twin turbo mode 1-2 in the run-up mode (see FIG. 14), or from the single turbo mode to the twin turbo mode. When it is determined that the switching has started, the exhaust switching valve, the intake bypass valve, and the intake switching valve are controlled according to the 1-2 approach mode (see FIG. 14). Further, the control device 70 has determined that the 2-1 approach mode (see FIG. 15), which is currently switching from the twin turbo mode to the single turbo mode, or the start of switching from the twin turbo mode to the single turbo mode is started. At this time, the exhaust switching valve, the intake bypass valve, and the intake switching valve are controlled according to the 2-1 approach mode (see FIG. 15). Further, when the control device 70 determines that the turbo mode is not the 1-2 approach mode or the 2-1 approach mode but the single turbo mode, the exhaust switching valve, the intake bypass valve, and the intake switching valve are set to the single turbo mode. (See FIGS. 14 and 15). Further, when the control device 70 determines that the turbo mode is not the 1-2 approach mode or the 2-1 approach mode but the twin turbo mode, the exhaust switching valve, the intake bypass valve, and the intake switching valve are set to the twin turbo mode. (See FIGS. 14 and 15). The periods T1 and T2 (see FIGS. 14 and 15) of the 1-2 run-up mode and the 2-1 run-up mode are, for example, about 1 [second]. Further, since the determination of the turbo mode and the switching control of the turbo mode are the same as the existing processing, the details will be omitted.

In step S025, the control device 70 obtains and stores the (provisional) allowable upper limit injection amount based on the rotation speed of the internal combustion engine and the allowable upper limit injection amount characteristic (allowable upper limit injection amount characteristic of the characteristic LM3 shown in FIG. 9). Then, the process proceeds to step S030.

In step S030, the control device 70 determines whether or not the operating region is one turbo region. The control device 70 proceeds to step S050C when the operating area is one turbo region (Yes), and proceeds to step S035 when the operating region is not one turbo region (No).

When the process proceeds to step S035, the control device 70 determines whether or not the operating region is the two turbo region. The control device 70 proceeds to step S050B when the operating area is the 2 turbo region (Yes), and proceeds to step S040 when the operating region is not the 2 turbo region (No).

When the process proceeds to step S050B, the control device 70 is based on the characteristic G3 shown in FIG. 9 so that the injection amount becomes the target torque (closer) as the injection amount when controlled in the twin turbo mode in the two turbo region. The fuel injection amount is obtained, and the obtained fuel injection amount is stored in the (provisional) injection amount. Further, the control device 70 stores the (provisional) allowable upper limit injection amount obtained in step S025 as the allowable upper limit injection amount when controlled in the twin turbo mode within the two turbo regions in the final allowable upper limit injection amount, and steps. Proceed to process to S060.

When the process proceeds to step S050C, the control device 70 is based on the characteristic G3 shown in FIG. 9 so that the injection amount when controlled in the single turbo mode within one turbo region is the target torque (to approach). The fuel injection amount is obtained, and the obtained fuel injection amount is stored in the (provisional) injection amount. Further, the control device 70 stores the (provisional) allowable upper limit injection amount obtained in step S025 as the allowable upper limit injection amount when controlled in the single turbo mode within one turbo region in the final allowable upper limit injection amount, and steps. Proceed to process to S060.

When the process proceeds to step S040, the control device 70 executes the process SA000 and proceeds to the process to step S050A. The processing SA000 is a processing for calculating the total loss difference and the turbo mode adjustment injection amount, and the details will be described later.

In step S050A, the control device 70 executes the process SB000 and proceeds to the process to step S060. The process SB000 is a process for calculating the (provisional) injection amount and the final allowable upper limit injection amount in the turbo switching region, and the details will be described later.

When the control device 70 (CPU71) executing the process of the process SB000 is in the turbo switching region, the output torque of the internal combustion engine 10 when controlled in the single turbo mode and the output torque of the internal combustion engine 10 when controlled in the twin turbo mode are used. The (fuel) injection amount when controlled in the single turbo mode and the (fuel) injection amount when controlled in the twin turbo mode are different so that the difference from the output torque of the internal combustion engine 10 is small. It corresponds to the switching region injection amount adjusting unit 71A (see FIG. 1) for obtaining the (fuel) injection amount.

When the process proceeds to step S060, the control device 70 determines whether or not the (provisional) injection amount is equal to or less than the final allowable upper limit injection amount. The control device 70 proceeds to step S065A when the (provisional) injection amount is equal to or less than the final allowable upper limit injection amount (Yes), and steps when the (provisional) injection amount is not equal to or less than the final allowable upper limit injection amount (No). Proceed to process to S065B.

When the process proceeds to step S065A, the control device 70 stores the (provisional) injection amount in the final injection amount, and ends the process shown in FIG.

When the process proceeds to step S065B, the control device 70 stores the final allowable upper limit injection amount in the final injection amount, and ends the process shown in FIG.

Then, the control device 70 controls the injector by using the final injection amount in the injector drive process (not shown).

● [Details of processing SA000 (Fig. 12)]
Next, the details of the processing SA000 (calculation of the total loss difference and the turbo mode adjustment injection amount) will be described with reference to the flowchart shown in FIG. When the control device 70 proceeds to the process in step S040 shown in FIG. 11, the control device 70 proceeds to the process in step SA010 shown in FIG.

Based on the operating state detected in step S010, the control device 70 in step SA010 has a pumping loss at 1 turbo, which is a pumping loss in the case of a single turbo, and a pumping loss at 2 turbos, which is a pumping loss in the case of a twin turbo. Estimate the loss. Then, the control device 70 obtains and stores the pumping loss difference, which is the difference between the pumping loss at 1 turbo and the pumping loss at 2 turbo, and proceeds to step SA020. There are various methods for calculating the pumping loss based on the operating state, and the method is not particularly limited.

The control device 70 (CPU71) executing the process of step SA010 estimates the pumping loss at 1 turbo and the pumping loss at 2 turbos, and obtains the pumping loss difference in the pumping loss estimation unit 71B (see FIG. 1). It is equivalent. The pumping loss at one turbo is the loss of kinetic energy used for intake and exhaust of the internal combustion engine when controlled in the single turbo mode. Further, the pumping loss at the time of 2 turbos is a loss of kinetic energy used for intake and exhaust of the internal combustion engine when controlled in the twin turbo mode. The pumping loss difference is the difference between the pumping loss at 1 turbo and the pumping loss at 2 turbo.

Based on the detected operating state in step SA020, the control device 70 has a cooling loss at 1 turbo, which is a cooling loss in the single turbo mode, and a cooling loss at 2 turbo, which is a cooling loss in the twin turbo mode. , And proceed to step SA030. There are various methods for calculating the cooling loss based on the operating state, and the method is not particularly limited.

In step SA030, the control device 70 estimates the total loss at 1 turbo including the pumping loss at 1 turbo and the cooling loss at 1 turbo, and calculates the total loss at 2 turbo including the pumping loss at 2 turbo and the cooling loss at 2 turbo. presume. The total loss at 1 turbo and the total loss at 2 turbos may include losses such as mechanical loss (at 1 turbo and 2 turbos) and exhaust loss. Then, the control device 70 obtains and stores the total loss difference, which is the difference between the total loss at 1 turbo and the total loss at 2 turbos, and proceeds to step SA040.

The control device 70 (CPU71) executing the processes of steps SA020 and SA030 estimates the total loss at 1 turbo and the total loss at 2 turbos, and obtains the total loss difference. Total loss estimation unit 71C (see FIG. 1). ). The total loss at 1 turbo is an energy loss including a cooling loss at 1 turbo and a pumping loss at 1 turbo, which are heat energy losses of the internal combustion engine when controlled in the single turbo mode. Further, the total loss at 2 turbos is an energy loss including a cooling loss at 2 turbos and a pumping loss at 2 turbos, which is a loss of thermal energy of the internal combustion engine when controlled in the twin turbo mode. The total loss difference is the difference between the total loss at 1 turbo and the total loss at 2 turbos.

In step SA040, the control device 70 obtains and stores the turbo mode adjustment injection amount based on the total loss difference, ends the process shown in FIG. 12, and proceeds to step S060 shown in FIG. The turbo mode adjustment injection amount is the amount of fuel required to generate the torque which is the total loss difference. The processing of steps SA020 and SA030 may be omitted, and the turbo mode adjustment injection amount may be obtained by using the pumping loss difference instead of the total loss difference.

● [Details of processing SB000 (FIG. 13)]
Next, the details of the process SB000 (calculation of the (provisional) injection amount in the turbo switching region and the final allowable upper limit injection amount) will be described with reference to the flowchart shown in FIG. When the control device 70 proceeds to the process in step S050A shown in FIG. 11, the control device 70 proceeds to the process in step SB010 shown in FIG.

In step SB010, the control device 70 sets the fuel injection amount based on the characteristic G3 shown in FIG. 9 so as to be the target torque (close to) as the injection amount when controlled in the twin turbo mode in the turbo switching region. The calculated fuel injection amount is stored in the 2 turbo injection amount. Further, the control device 70 stores the injection amount obtained by adding (increasing) the turbo mode adjustment injection amount to the two turbo injection amounts in one turbo injection amount. Further, the control device 70 obtains the allowable upper limit injection amount based on the characteristic LM3 shown in FIG. 9 as the allowable upper limit injection amount when controlled in the twin turbo mode in the turbo switching region, and sets the obtained allowable upper limit injection amount to 2 turbos. Stored in the allowable upper limit injection amount. Further, the control device 70 stores the injection amount obtained by adding (increasing) the turbo mode adjustment injection amount to the 2 turbo allowable upper limit injection amount in the 1 turbo allowable upper limit injection amount. Then, the control device 70 proceeds to the process to step SB015.

In step SB015, the control device 70 determines whether or not it is currently in the 1-2 approach mode (during switching from the single turbo mode to the twin turbo, see FIG. 14). The control device 70 proceeds to step SB410 when it is in the 1-2 run-up mode (Yes), and proceeds to step SB020 when it is not in the 1-2 run-up mode (No).

When the process proceeds to step SB020, the control device 70 determines whether or not it is currently in the 2-1 approach mode (during switching from the twin turbo mode to the single turbo mode, see FIG. 15). When the control device 70 is in the 2-1 approach mode (Yes), the process proceeds to step SB310, and when the control device 70 is not in the 2-1 approach mode (No), the process proceeds to step SB030.

When the process proceeds to step SB030, the control device 70 determines whether or not it is currently in the single turbo mode. The control device 70 proceeds to step SB120 when it is in the single turbo mode (Yes), and proceeds to step SB220 when it is not in the single turbo mode (No).

When the process proceeds to step SB120, the control device 70 stores one turbo injection amount in the (provisional) injection amount and proceeds to step SB130.

In step SB130, the control device 70 stores one turbo allowable upper limit injection amount in the final allowable upper limit injection amount, ends the process shown in FIG. 13, and proceeds to step S060 shown in FIG.

When the process proceeds to step SB 220, the control device 70 stores the 2 turbo injection amount in the (provisional) injection amount and proceeds to the process to step SB 230.

In step SB230, the control device 70 stores the 2 turbo allowable upper limit injection amount in the final allowable upper limit injection amount, ends the process shown in FIG. 13, and proceeds to step S060 shown in FIG.

When the process proceeds to step SB310, the control device 70 has a turbo mode adjustment injection amount ΔQ21 (see FIG. 15), which is the difference between the 1 turbo injection amount and the 2 turbo injection amount, and the transition of the switching timer (2-1 run-up mode). It is time, and the increase amount based on (see FIG. 15) is calculated, and the process proceeds to step SB320.

In step SB320, the control device 70 stores the injection amount obtained by adding the increase amount to the two turbo injection amounts in the (provisional) injection amount, and proceeds to the process to step SB330.

In step SB330, the control device 70 stores the injection amount obtained by adding the increase amount to the 2 turbo allowable upper limit injection amount in the final allowable upper limit injection amount, ends the process shown in FIG. 13, and proceeds to step S060 shown in FIG. To proceed. In the processing of steps SB310 to SB330, as shown in FIG. 15, in the 2-1 approach mode, the (provisional) injection amount and the final allowable upper limit injection amount are gradually increased to avoid sudden changes.

When the process proceeds to step SB410, the control device 70 has a turbo mode adjustment injection amount ΔQ12 (see FIG. 14), which is the difference between the 1 turbo injection amount and the 2 turbo injection amount, and the transition of the switching timer (1-2 run-up mode). It is time, and the reduction amount based on (see FIG. 14) is calculated, and the process proceeds to step SB420.

In step SB420, the control device 70 stores the injection amount obtained by subtracting the reduction amount from one turbo injection amount in the (provisional) injection amount, and proceeds to step SB430.

In step SB430, the control device 70 stores the injection amount obtained by subtracting the reduction amount from the 1 turbo allowable upper limit injection amount in the final allowable upper limit injection amount, ends the process shown in FIG. 13, and proceeds to step S060 shown in FIG. To proceed. In the process of steps SB410 to SB430, as shown in FIG. 14, in the 1-2 approach mode, the (provisional) injection amount and the final allowable upper limit injection amount are gradually reduced to avoid sudden changes.

● [Other embodiments (FIGS. 16 and 17)]
In the description of the above-described embodiment, the fuel injection amount characteristic G3 and the allowable upper limit injection amount characteristic LM3 shown in FIG. 9 are used so as to obtain (approach) the target torque. As the fuel injection amount characteristic G3, the fuel injection amount characteristic G2 in the twin turbo mode is adopted in the turbo switching region. Further, as the characteristic LM3 of the allowable upper limit injection amount, the characteristic LM2 of the allowable upper limit injection amount of the twin turbo mode is adopted in the turbo switching region.

On the other hand, in another embodiment described below, as shown in FIG. 16, the characteristic G4 is used for the fuel injection amount, and the characteristic LM4 is used for the allowable upper limit injection amount. The fuel injection amount characteristic G4 is different in that the fuel injection amount characteristic G1 in the single turbo mode is adopted in the turbo switching region. Further, the characteristic LM4 of the allowable upper limit injection amount is different in that the characteristic LM1 of the allowable upper limit injection amount of the single turbo mode is adopted in the turbo switching region.

Due to the above differences, the processing of the control device 70 is changed from the processing of step SB010 of the processing SB000 shown in FIG. 13 to the processing of step SB010A of the processing SB000 shown in FIG. Hereinafter, the processing of the changed step SB010A will be described. Since there is no change in other processes, the description of other processes will be omitted. When the control device 70 proceeds to the process in step S050A shown in FIG. 11, the control device 70 proceeds to the process in step SB010A shown in FIG.

In step SB010A, the control device 70 obtains a fuel injection amount based on the characteristic G4 shown in FIG. 16 as an injection amount when controlled in the single turbo mode in the turbo switching region, and the obtained fuel injection amount is one turbo injection. Remember in quantity. Further, the control device 70 stores the injection amount obtained by subtracting (reducing) the turbo mode adjustment injection amount from the 1 turbo injection amount in the two turbo injection amounts. Further, the control device 70 obtains the allowable upper limit injection amount based on the characteristic LM4 shown in FIG. 16 as the allowable upper limit injection amount when controlled in the single turbo mode in the turbo switching region, and the obtained allowable upper limit injection amount is 1 turbo. Stored in the allowable upper limit injection amount. Further, the control device 70 stores the injection amount obtained by subtracting (reducing) the turbo mode adjustment injection amount from the 1 turbo allowable upper limit injection amount in the 2 turbo allowable upper limit injection amount. Then, the control device 70 proceeds to the process to step SB015.

As described above, according to the control device of the internal combustion engine described in the present embodiment, in the internal combustion engine having two turbochargers, the output is in the turbo switching region where both modes of single turbo mode and twin turbo mode are possible. When controlling the torque to be the target torque, the difference between the output torque in the single turbo mode and the output torque in the twin turbo mode can be further reduced by a simpler process.

The control device for an internal combustion engine of the present invention is not limited to the configuration, structure, processing procedure, operation, etc. described in the present embodiment, and various changes, additions, and deletions can be made without changing the gist of the present invention. be. Further, the internal combustion engine system is not limited to the one described in the present embodiment, and can be applied to various internal combustion engine systems including a first turbocharger and a second turbocharger.

Further, the processing procedure of the control device is not limited to the processing procedure described in the present embodiment. Further, the above (≧), the following (≦), the larger (>), the less than (<), etc. may or may not include the equal sign.

1 Internal Combustion Engine System 10 Internal Combustion Engine 11A Intake Pipe 11B1 First Intake Inflow Passage 11B2 Second Intake Inflow Passage 11C1 First Intake Discharge Passage 11C2 Second Intake Discharge Passage 11CB Intake Bypass Passage 11D Confluence Intake Passage 11E Intake Manifold 12A1, 12A2 Exhaust Manifold 12B1 1st exhaust inflow passage 12B2 2nd exhaust inflow passage 12BB Exhaust communication passage 12C1 1st exhaust discharge passage 12C2 2nd exhaust discharge passage 12D Confluence exhaust passage 13A EGR passage 21 Intake flow rate detecting means 22A Intake manifold inner boost pressure detecting means 22B Exhaust pressure detecting means 22C Differential pressure detecting means 22D Atmospheric pressure detecting means 22E Intake temperature detecting means 22F Supercharging pressure detecting means 22G Supercharging pressure detecting means 23 Fuel pressure detecting means 24 Coolant temperature detecting means 25A Crank angle detecting means 25B Cam angle detecting means 26 Exhaust temperature detecting means 27 Accelerator pedal depression amount detecting means 28A Intake temperature detecting means in intake manifold 30 Supercharging system 31 First turbocharger 31A First compressor 31B First turbine 31C First variable nozzle 31D, 32D Nozzle driving means 31E, 32E Nozzle opening detection means 32 2nd turbocharger 32A 2nd compressor 32B 2nd turbine 32C 2nd variable nozzle 33 Throttle device 34 EGR cooler 35 EGR valve 38 Intercooler 41 Fuel pressure adjustment pump 42 Common rail 51 Oxidation catalyst 52 DPF
53 Urea SCR
61 Intake bypass valve 62 Intake switching valve 63 Exhaust switching valve 70 Control device 71 CPU
71A Switching area injection amount adjustment unit 71B Pumping loss estimation unit 71C Total loss estimation unit 73 Storage means PA1 Intake branch point PA2 Intake intermediate junction PA3 Intake final junction PB3 Exhaust final junction SP1 1 Turbo pumping loss SP2 2 Turbo pumping Loss SR1 1 Other loss at turbo SR2 2 Other loss at turbo SS1 1 Total loss at turbo SS2 2 Total loss at turbo

Claims (4)

The operating state of the internal combustion engine having the first turbocharger and the second turbocharger is detected, and the injection amount of fuel injected into the cylinder of the internal combustion engine is controlled based on the detected operating state, and the first turbo is used. In an internal combustion engine control device that switches between a single turbo mode in which supercharging is performed using only a charger and a twin turbo mode in which supercharging is performed using both the first turbocharger and the second turbocharger.
In the control device, as an operating area of the internal combustion engine,
One turbo region, which is the operating region controlled in the single turbo mode, and
The two turbo regions, which are the operating regions controlled in the twin turbo mode, and
Turbo switching which is an operating region set between the 1 turbo region and the 2 turbo region and where switching from the single turbo mode to the twin turbo mode or switching from the twin turbo mode to the single turbo mode occurs. The area and is set,
The control device is
When the target torque of the internal combustion engine is obtained based on the operating state and the injection amount is obtained so that the output torque of the internal combustion engine approaches the target torque, the operating region determined based on the operating state is the operating region. In the turbo switching region, the difference between the output torque of the internal combustion engine when controlled in the single turbo mode and the output torque of the internal combustion engine when controlled in the twin turbo mode is small. It has a switching region injection amount adjusting unit that obtains the injection amount so that the injection amount when controlled in the single turbo mode and the injection amount when controlled in the twin turbo mode are different values. ,
Internal combustion engine control device. The control device for an internal combustion engine according to claim 1.
The control device has
An allowable upper limit injection amount, which is an upper limit amount of the allowable injection amount, is set from the 1 turbo region to the 2 turbo regions via the turbo switching region.
The control device is
When the operating region determined based on the operating state by the switching region injection amount adjusting unit is the turbo switching region, the injection amount and the allowable upper limit injection amount when controlled in the single turbo mode are determined. A value larger than the injection amount and the allowable upper limit injection amount when controlled in the twin turbo mode.
Alternatively, when the operating region determined based on the operating state by the switching region injection amount adjusting unit is the turbo switching region, the switching region injection amount adjusting unit controls in the twin turbo mode. The injection amount and the allowable upper limit injection amount are set to be smaller than the injection amount and the allowable upper limit injection amount when controlled in the single turbo mode.
Internal combustion engine control device. The control device for an internal combustion engine according to claim 2.
The control device is
When the operating region determined based on the operating state is the turbo switching region, it is a loss of kinetic energy used for intake and exhaust of the internal combustion engine when controlled in the single turbo mode. The pumping loss and the pumping loss at 2 turbos, which is the loss of kinetic energy used for the intake and exhaust of the internal combustion engine when controlled in the twin turbo mode, are estimated and the estimated pumping loss at 1 turbo. It has a pumping loss estimation unit that obtains the pumping loss difference, which is the difference between the pumping loss and the pumping loss at the time of 2 turbos.
The control device is
When the operating region determined based on the operating state by the switching region injection amount adjusting unit is the turbo switching region, the turbo mode adjusted injection amount is obtained based on the pumping loss difference, and the single turbo mode is used. The controlled injection amount and the allowable upper limit injection amount are increased by the turbo mode adjustment injection amount with respect to the injection amount and the allowable upper limit injection amount when controlled in the twin turbo mode.
Alternatively, when the operating region determined based on the operating state by the switching region injection amount adjusting unit is the turbo switching region, the turbo mode adjusted injection amount is obtained based on the pumping loss difference, and the twin The injection amount and the allowable upper limit injection amount when controlled in the turbo mode are reduced by the turbo mode adjustment injection amount with respect to the injection amount and the allowable upper limit injection amount when controlled in the single turbo mode.
Internal combustion engine control device. The control device for an internal combustion engine according to claim 3.
The control device is
When the operating region determined based on the operating state is the turbo switching region, one turbo cooling loss and one turbo pumping, which are heat energy losses of the internal combustion engine when controlled in the single turbo mode. Energy including 1 turbo total loss, which is an energy loss including loss, 2 turbo cooling loss, which is a loss of heat energy of the internal combustion engine when controlled in the twin turbo mode, and 2 turbo pumping loss. It has a total loss estimation unit that estimates the total loss at 2 turbos, which is the loss, and obtains the total loss difference, which is the difference between the estimated total loss at 1 turbo and the total loss at 2 turbos.
The control device is
When the operating region determined based on the operating state by the switching region injection amount adjusting unit is the turbo switching region, the turbo mode adjusted injection amount is obtained based on the total loss difference.
Internal combustion engine control device.

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