Control device

Abstract

It includes: an acquisition unit 221 for acquiring the temperature of the engine coolant; a determination unit 222 for determining the cumulative amount of fuel injection after the engine starts; a determination unit 224 for determining, based on the temperature and cumulative amount of coolant, whether the engine meets the necessary conditions for increasing the number of fuel injections per cycle from the injector 11 to the engine cylinder; and a split injection unit 225 for increasing the number of fuel injections per cycle from the injector 11 to the engine cylinder if the determination unit 224 determines that the engine meets the necessary conditions for increasing the number of fuel injections per cycle from the injector 11 to the engine cylinder.

Description

Technical Field

[0001] This invention relates to a control device for injecting fuel from an injector into an engine cylinder. Background Technology

[0002] To improve the activity of catalysts in emission gas purification devices such as DPF (Diesel Particulate Filter) installed in the exhaust passage of vehicles with diesel engines, methods have been proposed to increase exhaust temperature. For example, Patent Document 1 proposes a method to increase exhaust temperature by dividing fuel injection into more than two stages.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-250120 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] When fuel injection is split into more than two parts, the amount of fuel injected each time decreases. When the engine is first started, the temperature inside the cylinders is relatively low, so splitting fuel injection into more than two parts can easily lead to poor combustion.

[0008] The present invention was made in view of this problem, and its object is to provide a control device that can suppress poor fuel quality in an engine while improving the activity of catalysts such as DPF.

[0009] Problem-solving methods

[0010] The control device of the first aspect of the present invention includes: an acquisition unit for acquiring the temperature of the engine's coolant; a determination unit for determining the cumulative amount of fuel injection after the engine is started; a determination unit for determining, based on the temperature of the coolant and the cumulative amount, whether the engine meets the necessary conditions for increasing the number of fuel injections per cycle from the injector to the cylinder of the engine; and a split injection unit for increasing the number of fuel injections per cycle from the injector to the cylinder of the engine if the determination unit determines that the engine meets the necessary conditions for increasing the number of fuel injections per cycle from the injector to the cylinder of the engine.

[0011] The control device may also include a timing control unit, which advances the timing of opening the exhaust valve when the determination unit determines that the engine meets the necessary conditions for increasing the number of fuel injections per cycle from the injector to the cylinder of the engine.

[0012] The control device may also include a reference setting unit that sets a reference cumulative amount, which represents the cumulative amount of fuel injection required to increase the number of fuel injections per cycle from the injector to the cylinder of the engine. In setting this reference cumulative amount, the lower the temperature of the engine coolant obtained by the acquisition unit, the higher the reference cumulative amount is set. The determination unit may also determine that the engine meets the necessary condition for increasing the number of fuel injections per cycle from the injector to the cylinder of the engine if the cumulative amount of fuel injection after the engine starts is greater than the reference cumulative amount set by the reference setting unit.

[0013] The reference setting unit may also refer to a table that associates the engine coolant temperature with reference cumulative quantity candidates, and set the reference cumulative quantity candidate associated with the coolant temperature obtained by the acquisition unit in the table as the reference cumulative quantity. The acquisition unit may also acquire the vehicle's intake air temperature, and the reference setting unit may also refer to a table that associates the engine coolant temperature, intake air temperature, and reference cumulative quantity candidates, and set the reference cumulative quantity candidate associated with the coolant temperature obtained by the acquisition unit and the acquired intake air temperature in the table as the reference cumulative quantity.

[0014] The acquisition unit can also acquire the vehicle's exhaust temperature. If the exhaust temperature acquired by the acquisition unit exceeds a target value, the segmented injection unit may not increase the number of fuel injections per cycle from the injector to the cylinder of the engine. The acquisition unit can also acquire the vehicle's intake air temperature, and the reference setting unit can set a reference accumulation amount based on the coolant temperature and the intake air temperature acquired by the acquisition unit.

[0015] Invention Effects

[0016] According to the present invention, it has the effect of improving the activity of catalysts such as DPF while suppressing poor fuel quality in the engine. Attached Figure Description

[0017] Figure 1 This is a diagram showing an outline of the vehicle in the implementation method.

[0018] Figure 2 It is a diagram showing the structure of a vehicle.

[0019] Figure 3 This diagram shows the situation where the timing of opening the exhaust valve is advanced, as determined by the timing control unit.

[0020] Figure 4This is a flowchart illustrating the preheating process of the aftertreatment unit and the urea SCR, which is controlled by a control device. Detailed Implementation

[0021] [Overview of the Control Device]

[0022] Figure 1 This is a schematic diagram showing the vehicle 100 according to this embodiment. The vehicle 100 includes an engine 1 and a control unit 2. The engine 1 is, for example, a diesel engine. Within the engine 1, an injector 11 injects fuel into the cylinder. The injector 11 injects fuel into the cylinder at a predetermined number of fuel injections per cycle. For example, the number of fuel injections is set to maximize fuel combustion efficiency. One cycle is the period from the intake of air into the cylinder to the re-intake of air into the cylinder. The piston 12 is mounted at the crankshaft 13 mounting position (…). Figure 1 (P in the middle).

[0023] In the cylinder, the fuel, expanded by ignition, pushes down the piston 12, causing the crankshaft 13 to rotate. Then, if the exhaust valve 14 opens, the rotation of the crankshaft 13 causes the piston 12 to... Figure 1 The thick arrow in the middle indicates that it is pushed upwards, and the combustion gases are as follows: Figure 1 The thin arrow in the image indicates that it is being pushed out of the cylinder.

[0024] Control device 2 is implemented, for example, by an ECU (Electronic Control Unit), which electronically controls various parts of vehicle 100 via a computer. When engine 1 is first started, and the temperature of the catalyst in the aftertreatment system (Diesel Particulate Filter, DPF) or urea SCR (Selective Catalytic Reduction) of engine 1 is low, control device 2 increases the number of fuel injections per cycle from injector 11 into the cylinders of engine 1, thereby raising the temperature of the combustion gases discharged from the cylinders. In this way, control device 2 preheats the catalyst in the aftertreatment system or urea SCR of engine 1, suppressing the reduction in exhaust purification capacity caused by the low temperature of these catalysts.

[0025] Sometimes, the temperature inside the cylinders of engine 1 is low immediately after starting. If control device 2 increases the number of fuel injections per cycle before the temperature inside the cylinders of engine 1 rises, poor fuel quality inside the cylinders of engine 1 may occur. Therefore, control device 2 determines whether engine 1 meets the necessary conditions for increasing the number of fuel injections per cycle based on the temperature of the coolant in engine 1 and the cumulative value of the fuel injection quantity after engine 1 starts.

[0026] When the control device 2 determines that the engine 1 meets the necessary conditions for increasing the number of fuel injections per cycle, it increases the number of fuel injections per cycle. In this way, the control device 2 can preheat the catalyst of the aftertreatment unit or urea SCR. When the control device 2 determines that the engine 1 does not meet the necessary conditions for increasing the number of fuel injections per cycle, it does not increase the number of fuel injections per cycle, thus suppressing fuel inefficiencies in the engine 1.

[0027] [Vehicle Composition]

[0028] Figure 2 This diagram shows the structure of vehicle 100. Vehicle 100 includes a water temperature sensor 31, an intake air temperature sensor 32, an exhaust air temperature sensor 33, an injector 11, a variable valve mechanism 34, and a control device 2. The control device 2 includes a storage unit 21 and a control unit 22. The control unit 22 includes an acquisition unit 221, a determination unit 222, a reference setting unit 223, a judgment unit 224, a segmented injection unit 225, and a timing control unit 226.

[0029] The coolant temperature sensor 31 measures the temperature of the coolant in engine 1. The coolant temperature sensor 31 inputs the measured coolant temperature of engine 1 to the acquisition unit 221. The intake air temperature sensor 32 measures, for example, the temperature of the intake air drawn into the inlet of engine 1. The intake air temperature sensor 32 inputs the measured intake air temperature to the acquisition unit 221. The exhaust air temperature sensor 33 measures, for example, the exhaust temperature near, for example, the aftertreatment device in the rear stage of engine 1. The exhaust air temperature sensor 33 inputs the measured exhaust temperature to the acquisition unit 221.

[0030] Injector 11 injects fuel into the cylinder of engine 1. Injector 11 injects fuel into the cylinder at a predetermined number of fuel injections per cycle. Variable Valve Timing (VVT) 34 uses hydraulic pressure or the like to slightly rotate the camshaft relative to the crankshaft, thereby advancing or delaying the timing of opening the exhaust valve 14.

[0031] The storage unit 21 may include storage media such as ROM (Read Only Memory) and RAM (Random Access Memory). The storage unit 21 stores various programs or data for enabling the control unit 22 to function. The control unit 22 executes the programs stored in the storage unit 21, thereby functioning as the acquisition unit 221, the determination unit 222, the reference setting unit 223, the judgment unit 224, the segmented injection unit 225, and the timing control unit 226.

[0032] The acquisition unit 221 acquires the temperature of the coolant in the engine 1. For example, the acquisition unit 221 acquires the temperature of the coolant in the engine 1 from the coolant temperature sensor 31. The acquisition unit 221 acquires the intake air temperature of the vehicle 100. The acquisition unit 221 acquires the exhaust air temperature of the vehicle 100. For example, the acquisition unit 221 acquires the intake air temperature and exhaust air temperature of the vehicle 100 from the intake air temperature sensor 32 and the exhaust air temperature sensor 33, respectively. The acquisition unit 221 outputs the acquired coolant temperature, intake air temperature, and exhaust air temperature to the reference setting unit 223.

[0033] The determination unit 222 determines the cumulative amount of fuel injection after engine 1 starts. The storage unit 21 stores historical information linking fuel injection amount and injection time, and the start time of engine 1. The determination unit 222 reads the historical information of fuel injection amount and the start time of engine 1 from the storage unit 21, and determines the cumulative amount of fuel injection after the start time of engine 1. The determination unit 222 outputs the determined cumulative amount of fuel injection to the judgment unit 224.

[0034] [Setting the baseline cumulative amount]

[0035] The reference setting unit 223 sets a reference cumulative amount, which represents the necessary cumulative amount of fuel injection required to increase the number of fuel injections per cycle from the injector 11 into the cylinder of the engine 1. During the period when the control unit 22 is operating in the reference cumulative amount setting mode, the lower the temperature of the engine 1's coolant acquired by the acquisition unit 221, the higher the reference cumulative amount is set by the reference setting unit 223. Conversely, during the period when the control unit 22 is operating in the reference cumulative amount setting mode, the higher the temperature of the engine 1's coolant acquired by the acquisition unit 221, the lower the reference cumulative amount is set by the reference setting unit 223. As an example, the control unit 22 operates in the setting mode for a predetermined period after the start of use of the vehicle 100, and for a certain period after a predetermined time has elapsed since the engine 1 of the vehicle 100 was started.

[0036] Furthermore, during the reference accumulation setting mode, the lower the intake air temperature acquired by the acquisition unit 221, the higher the reference accumulation value set by the reference setting unit 223. On the other hand, during the reference accumulation setting mode, the higher the intake air temperature acquired by the acquisition unit 221, the lower the reference accumulation value set by the reference setting unit 223.

[0037] More specifically, the storage unit 21 stores a table that correlates the engine's coolant temperature, intake air temperature, and a reference cumulative quantity candidate. The reference setting unit 223 reads this table from the storage unit 21. Referring to the read table, the reference setting unit 223 sets the reference cumulative quantity candidate correlated with the coolant temperature and intake air temperature obtained by the acquisition unit 221 in the table as the reference cumulative quantity. The reference setting unit 223 outputs the set reference cumulative quantity to the determination unit 224.

[0038] [Determine whether the necessary conditions for increasing the number of fuel injections are met]

[0039] When the temperature inside the cylinder of engine 1 is low, there is a risk of fuel insufficiency in engine 1 if the number of fuel injections from injector 11 to the cylinder of engine 1 is increased in each cycle. Therefore, before increasing the number of fuel injections from injector 11 to the cylinder of engine 1 in each cycle, determination unit 224 determines whether engine 1 meets the necessary conditions for increasing the number of fuel injections in each cycle.

[0040] For example, the determination unit 224 determines whether the engine 1 meets the necessary condition based on the temperature of the cooling water and the cumulative amount of fuel injection. If the cumulative amount of fuel injection after the engine 1 starts is greater than the reference cumulative amount set by the reference setting unit 223, the determination unit 224 determines that the engine 1 meets the necessary condition. On the other hand, if the cumulative amount of fuel injection after the engine 1 starts is less than the reference cumulative amount set by the reference setting unit 223, the determination unit 224 determines that the engine 1 does not meet the necessary condition.

[0041] If the determination unit 224 can obtain the temperature inside the cylinder of engine 1, it can determine whether engine 1 meets the necessary conditions. However, the determination unit 224 cannot directly measure the temperature inside the cylinder of engine 1. Therefore, it is considered that the determination unit 224 can refer to the temperature of the coolant in engine 1 instead of the temperature inside the cylinder of engine 1.

[0042] However, even if the coolant temperature is the same immediately after engine 1 starts and after a sufficient time has elapsed since starting, the temperature inside the cylinders of engine 1 will differ. Therefore, sometimes the determination unit 224 cannot output the same determination result when only the coolant temperature is considered as when the cylinder temperature is considered. Therefore, in addition to the coolant temperature, the determination unit 224 also considers the cumulative amount of fuel injection to determine whether engine 1 meets the necessary conditions. In this way, the determination unit 224 can improve the accuracy of its determination.

[0043] When the intake air temperature is low, the fuel is difficult to ignite in the cylinder of engine 1. Therefore, compared to a high intake air temperature, the cylinder of engine 1 requires a higher temperature. If the base cumulative amount is set to a value where the lower the intake air temperature, the higher the base cumulative amount, then if the cumulative amount of fuel injection after engine 1 starts is greater than this base cumulative amount, the determination unit 224 determines that engine 1 meets the necessary conditions. In this way, the determination unit 224 reflects the influence of intake air temperature in determining whether engine 1 meets the necessary conditions for increasing the fuel injection amount in each cycle, thus improving the accuracy of the determination.

[0044] [Increased fuel injection rate]

[0045] The split injection unit 225 controls the number of fuel injections per cycle from the injector 11 into the cylinder of the engine 1. If the determination unit 224 determines that the engine 1 meets the necessary conditions for increasing the number of fuel injections per cycle from the injector 11 into the cylinder of the engine 1, the split injection unit 225 increases the number of fuel injections per cycle from the injector 11 into the cylinder of the engine 1. Conversely, if the determination unit 224 determines that the engine 1 does not meet the necessary conditions, the split injection unit 225 does not increase the number of fuel injections per cycle.

[0046] If the exhaust temperature obtained by the acquisition unit 221 exceeds the target value, the segmented injection unit 225 does not need to further increase the exhaust temperature, and therefore does not increase the number of fuel injections per cycle from the injector 11 into the cylinder of the engine 1. The target value is, for example, the value that enables the exhaust gas purification capacity specified by regulations in the aftertreatment device or urea SCR of the engine 1.

[0047] [Advancing the opening time of the exhaust valve]

[0048] If the determination unit 224 determines that the engine 1 meets the necessary condition for increasing the number of fuel injections per cycle from the injector 11 into the cylinder of the engine 1, the timing control unit 226 advances the timing of opening the exhaust valve 14. If the determination unit 224 determines that the engine 1 does not meet the necessary condition, the timing control unit 226 does not advance the timing of opening the exhaust valve 14. Figure 3 (a) and Figure 3 (b) indicates the mounting position of the piston 12 on the crankshaft 13 during the period from the opening to the closing of the exhaust valve 14. Figure 1 A diagram showing the rotation of P in the diagram.

[0049] Figure 3(a) indicates the change in the mounting position of the piston 12 on the crankshaft 13 corresponding to the period from the opening to the closing of the exhaust valve 14 when the timing control unit 226 does not advance the timing of opening the exhaust valve 14 via the variable valve mechanism 34. Figure 3 In example (a), exhaust valve 14 opens when piston 12 reaches bottom dead center and closes after passing top dead center. Bottom dead center is... Figure 1 The piston 12 is installed at the position closest to the rotating shaft of the crankshaft 13, and the top dead center is the position where the piston 12 is installed furthest from the rotating shaft of the crankshaft 13.

[0050] Figure 3 (b) indicates the change in the mounting position of the piston 12 on the crankshaft 13 corresponding to the period from the opening to the closing of the exhaust valve 14 when the timing control unit 226 advances the timing of opening the exhaust valve 14 via the variable valve mechanism 34. When the timing control unit 226 advances the timing of opening the exhaust valve 14 via the variable valve mechanism 34, the exhaust valve 14 opens before the piston 12 reaches bottom dead center. By opening the exhaust valve 14 before the piston 12 reaches bottom dead center, the timing control unit 226 can deliver high-temperature exhaust gas to the aftertreatment unit and the urea SCR compared to opening the exhaust valve 14 when it reaches bottom dead center. Therefore, the timing control unit 226 can improve the advance heating effect of the aftertreatment unit and the urea SCR.

[0051] When the timing control unit 226 advances the timing of opening the exhaust valve 14 via the variable valve mechanism 34, it is virtually impossible for the engine 1 to experience fuel incompatibility. Therefore, even if the determination unit 224 determines that the engine 1 does not meet the necessary conditions for increasing the number of fuel injections per cycle from the injector 11 into the cylinder of the engine 1, the timing control unit 226 can still advance the timing of opening the exhaust valve 14.

[0052] [Steps for preheating]

[0053] Figure 4 This is a flowchart illustrating the preheating process of the aftertreatment device and urea SCR performed by the control device 2. This process begins when the operation receiving unit (not shown) receives an operation from the driver to start the engine 1 of the vehicle 100. First, the determining unit 222 determines the cumulative amount of fuel injection after the engine 1 is started (S101). The acquiring unit 221 acquires the temperature of the coolant in the engine 1 from the coolant temperature sensor 31 (S102). The acquiring unit 221 acquires the intake air temperature of the vehicle 100 from the intake air temperature sensor 32 (S103).

[0054] The reference setting unit 223 sets a reference cumulative amount based on the coolant temperature and intake air temperature of the engine 1 obtained by the acquisition unit 221. This reference cumulative amount represents the cumulative amount of fuel injection required to increase the number of fuel injections per cycle from the injector 11 into the cylinder of the engine 1 (S104). The determination unit 224 determines whether the cumulative amount of fuel injection determined by the determination unit 222 is greater than the reference cumulative amount (S105).

[0055] If the determination unit 224 determines that the cumulative amount of fuel injection determined by the determination unit 222 is greater than the reference cumulative amount (S105), the split injection unit 225 increases the number of fuel injections per cycle from the injector 11 into the cylinder of the engine 1 (S106). The timing control unit 226 advances the timing of opening the exhaust valve 14 (S107). The operation receiving unit determines whether to receive the driver's operation to stop the engine 1 (S108). If the operation receiving unit receives the driver's operation to stop the engine 1 (S108), the process ends.

[0056] If, in the determination of S105, the determination unit 224 determines that the cumulative amount of fuel injection determined by the determination unit 222 is below the reference cumulative amount (No in S105), the determination unit 224 proceeds to the processing of S108. If, in the determination of S108, the operation receiving unit does not receive the driver's operation to stop the engine 1 (No in S108), the process returns to S101.

[0057] [Effects of the control device in this embodiment]

[0058] According to this embodiment, the segmented injection unit 225 increases the number of fuel injections per cycle, thereby improving the activity of the catalyst in the aftertreatment device or urea SCR of the engine 1. When the determination unit 224 determines that the engine 1 does not meet the necessary conditions for increasing the number of fuel injections per cycle, the segmented injection unit 225 does not increase the number of fuel injections per cycle, thus suppressing fuel insufficiency in the engine 1.

[0059] In this embodiment, an example is described where the reference setting unit 223 sets the reference cumulative amount by referring to a table that associates the engine coolant temperature, intake air temperature, and reference cumulative amount candidates. However, the present invention is not limited to this. For example, the reference setting unit 223 may also set the reference cumulative amount by referring to a table that associates the engine coolant temperature with reference cumulative amount candidates. The storage unit 21 stores a table that associates the engine coolant temperature with reference cumulative amount candidates. The reference setting unit 223 reads this table from the storage unit 21. Referring to the read table, the reference setting unit 223 sets the reference cumulative amount candidate associated with the coolant temperature obtained by the acquisition unit 221 in the table as the reference cumulative amount.

[0060] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. Various modifications and alterations can be made within its scope. For example, all or part of the device can be functionally or physically dispersed or combined in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments generated by the combination also include the effects of the original embodiments.

[0061] Figure Labels

[0062] 1. Engine

[0063] 2. Control device

[0064] 11 Injectors

[0065] 12 Pistons

[0066] 13 Crankshaft

[0067] 14. Exhaust valve

[0068] 21 Storage Department

[0069] 22 Control Department

[0070] 31 Water Temperature Sensor

[0071] 32 Intake air temperature sensor

[0072] 33 Exhaust Temperature Sensor

[0073] 34 Variable Valve Mechanism

[0074] 100 vehicles

[0075] 221 Acquisition Department

[0076] 222 Determination Department

[0077] 223 Reference Setting Section

[0078] 224 Judgment Department

[0079] 225 Split-jet section

[0080] 226 Timing Control Department

Claims

1. A control device comprising: The acquisition unit acquires the temperature of the engine's cooling water. The determining unit determines the cumulative amount of fuel injection after the engine starts; The reference setting unit sets a reference cumulative amount. In setting this reference cumulative amount, the lower the engine coolant temperature obtained by the acquisition unit, the higher the reference setting unit sets the reference cumulative amount. This reference cumulative amount represents the cumulative amount of fuel injection required to increase the number of fuel injections per cycle from the injector to the engine cylinder. The determination unit, based on the temperature of the cooling water and the cumulative amount, determines whether the engine meets the necessary conditions for increasing the number of fuel injections per cycle from the injector into the cylinder of the engine. The injection section is divided, and if the determination unit determines that the engine meets the necessary conditions for increasing the number of fuel injections per cycle from the injector to the cylinder of the engine, the number of fuel injections per cycle from the injector to the cylinder of the engine is increased; and The timing control unit advances the timing of opening the exhaust valve when the determination unit determines that the engine meets the necessary conditions for increasing the number of fuel injections per cycle from the injector to the cylinder of the engine. If the determination unit determines that the engine meets the necessary condition for increasing the number of fuel injections per cycle from the injector to the cylinder of the engine when the cumulative amount of fuel injection after the engine starts is greater than the reference cumulative amount set by the reference setting unit.

2. The control device according to claim 1, wherein, The reference setting unit refers to a table that associates the engine coolant temperature with a reference cumulative quantity candidate, and sets the reference cumulative quantity candidate associated with the coolant temperature obtained by the acquisition unit in the table as the reference cumulative quantity.

3. The control device according to claim 1, wherein, The acquisition unit acquires the vehicle's intake air temperature. The reference setting unit refers to a table that associates the engine's coolant temperature, intake air temperature, and reference cumulative quantity candidate, and sets the reference cumulative quantity candidate associated with the coolant temperature and intake air temperature obtained by the acquisition unit in the table as the reference cumulative quantity.

4. The control device according to claim 1, wherein, The acquisition unit acquires the vehicle's exhaust temperature. If the exhaust temperature obtained by the acquisition unit exceeds the target value, the segmented injection unit does not increase the number of fuel injections per cycle from the injector to the cylinder of the engine.

5. The control device according to claim 1, wherein, The acquisition unit acquires the vehicle's intake air temperature. The reference setting unit sets the reference cumulative amount based on the temperature of the cooling water and the intake air temperature obtained by the acquisition unit.

6. The control device according to claim 1, wherein the segmented injection unit: from the start of the engine until the determination unit determines that the cumulative amount of fuel injection after the engine starts is greater than the reference cumulative amount set by the reference setting unit, does not increase the number of fuel injections per cycle from the injector to the cylinder of the engine; and when the determination unit determines that the cumulative amount of fuel injection after the engine starts is greater than the reference cumulative amount set by the reference setting unit, increases the number of fuel injections per cycle from the injector to the cylinder of the engine.

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