JP6515974B2 - Engine control device - Google Patents

Description

  The present invention relates to control of a vehicle engine provided with a fuel injection valve.

Sulfur compounds may be contained in fuels such as light oil and gasoline used for vehicle engines. Therefore, when the mixture is burned in the combustion chamber, the combustion gas may contain sulfuric anhydride (SO ₃ ). Most of the anhydrous sulfuric acid generated in the combustion chamber is discharged to the exhaust system and post-treated in the aftertreatment device, but a trace amount of anhydrous sulfuric acid may remain in the combustion chamber. In particular, when exhaust gas recirculation (EGR) is performed, a portion of the sulfuric anhydride in the exhaust gas is sucked into the combustion chamber, whereby the sulfuric anhydride tends to remain in the combustion chamber.

It is known that when the engine is stopped and the temperature drops, the residual sulfuric acid remaining in the air in the combustion chamber can react with moisture to cause condensation of sulfuric acid (H ₂ SO ₄ ). When the sulfuric acid condensed in this manner is retained at the nozzle tip of the fuel injection valve, the peripheral portion of the injection hole at the nozzle tip may be corroded. As a result, when the diameter of the injection hole is expanded, the atomization of the fuel injected from the nozzle, and further, the mixing of the air and the fuel in the combustion chamber is deteriorated, and smoke is easily generated.

  The sulfuric acid which has condensed on the nozzle tip after engine stop can be removed by combustion in the next engine drive. Generally, in one driving cycle from engine start by turning on the ignition switch to engine stop by turning off the ignition switch, the engine is driven for at least several minutes. In such a general use mode, the sulfuric acid retained at the nozzle tip can be reliably removed by combustion, thereby avoiding corrosion of the nozzle tip by the sulfuric acid.

  In addition, the subject regarding the corrosion of the nozzle tip part by generation | occurrence | production of dew condensation also by patent document 1 is disclosed. With respect to this problem, in the technique of Patent Document 1, removal of sulfuric acid from the tip of the nozzle is promoted by continuing the idle operation after the ignition switch is turned off.

Patent No. 589 58559

  However, only a few users may use the vehicle in such a manner as to repeat a driving cycle in which engine driving time is less than a few minutes. As a specific example of such a mode of use, repeated short distance traveling between a home and a very near facility such as a convenience store, repeated changing of the parking position in the same site, etc. It can be mentioned.

  As described above, in a very short driving cycle which is not assumed as a general usage mode, sulfuric acid condensed on the nozzle tip of the fuel injection valve can not be removed with certainty, and after the engine is stopped It is likely to cause corrosion. In particular, corrosion of the nozzle by the sulfuric acid is likely to proceed if the very short driving cycle in cold weather is repeated.

  In the case where the idle operation is continued even after the ignition switch is turned off in order to achieve the reliable removal of sulfuric acid as in the technique of Patent Document 1, the occupant can not leave the vehicle until the engine is stopped. Therefore, it is not realistic to adopt the technology from the viewpoint of convenience, and another corrosion prevention measures are required.

  Therefore, the present invention provides an engine control device capable of effectively preventing the corrosion of the fuel injection valve of the engine even when a very short driving cycle, which is not assumed as a general use mode, is repeated. The task is to provide.

  In order to solve the above-mentioned subject, a control device of an engine concerning the present invention is characterized by having constituted as follows.

The invention according to claim 1 is a control device of an engine comprising a fuel injection valve for supplying fuel to a combustion chamber of the engine, and an idle speed control means for controlling an idle speed of the engine,
Protects the next driving cycle when target non-delivery operation is performed where the total fuel injection amount in one driving cycle from when the driving of the engine is started to when it stops is less than the predetermined target injection amount Equipped with protection mode setting means for setting mode cycles,
The idle speed control means executes fuel injection valve protection control to increase the idle speed of the engine in the protective mode cycle more than in normal idle operation.

  The "total fuel injection amount" is reset when one driving cycle is completed. That is, each driving cycle is started with the total fuel injection amount being zero. Further, the idle rotation speed after the increase by the “fuel injection valve protection control” may be set to, for example, a rotation speed equivalent to the upper limit value of the idle rotation speed in the idle up control performed at cold time.

The control device for an engine according to the invention of claim 2 is the invention according to the invention of claim 1,
The protection mode setting means regulates setting of the driving cycle, which is started before a predetermined time elapses from the end of the previous driving cycle, in the protection mode cycle.

A control device for an engine according to the invention described in claim 3 is the invention described in claim 1 or 2.
The protection mode setting means is characterized in that setting of a driving cycle started when the temperature of the engine coolant water is equal to or higher than a predetermined temperature is set to the protection mode cycle.

The control device for an engine according to the invention of claim 4 is the invention according to any one of claims 1 to 3.
The target injection amount is set according to the temperature of the engine coolant at the start of the driving cycle.

The engine control device according to the invention of claim 5 is the invention according to any one of claims 1 to 4.
An undelivered number counting means for counting the number of times of target unachieved operation
Reset means for resetting the number of counts of the target non-delivery operation to zero when the total fuel injection amount reaches the target injection amount;
The protection mode setting means is characterized in that setting of the next driving cycle to the protection mode cycle is restricted until the target non-delivery operation is counted a predetermined number of times.

The control device for an engine according to the sixth aspect of the present invention is the controller according to the fifth aspect of the present invention,
The non-delivery count counting means counts up the number of the non-targeted operation only when the non-targeted operation is performed in a driving cycle started a predetermined time or more after the end of the previous driving cycle. To be characterized.

  The "predetermined time" described in claim 6 may be the same time as the "predetermined time" described in claim 2, or may be a different time.

The control device for an engine according to the invention of claim 7 is the invention according to claim 5 or 6
The non-delivery count counting means counts up the number of the non-targeted operation only when the non-targeted operation is performed in a driving cycle started with the temperature of the engine coolant being lower than a predetermined temperature. It is characterized by doing.

An engine control apparatus according to the invention set forth in claim 8 is the invention set forth in any one of claims 1 to 7 described above,
The idle speed control means ends the fuel injection valve protection control when the total fuel injection amount in the protection mode cycle reaches the target injection amount.

The engine control device according to the invention as set forth in claim 9 is the invention as set forth in any one of the first to eighth inventions,
The vehicle equipped with the engine includes a transmission that changes the rotation of the engine and outputs the same to the drive wheels, and switching means for switching the transmission between a power transmittable state and a power transmittable state.
The idle rotation speed control means interrupts the fuel injection valve protection control when the transmission is in a power transmission enabled state.

  As a specific example of the "power transfer enable state" mentioned here, a state in which the shift range of the automatic transmission is the travel range (D range, R range, etc.), and the manual transmission has any gear position. The specific example of the “power transmission impossible state” is a state where the shift range of the automatic transmission is a non-traveling range (P range, N range, etc.) and a neutral state of the manual transmission. It can be mentioned.

The engine control device according to the invention as set forth in claim 10 is the invention as set forth in any one of the first to ninth inventions,
An automatic stop control means for automatically stopping the engine when a predetermined engine stop condition is satisfied;
The automatic stop control means is characterized in that the automatic stop of the engine is not performed during execution of the fuel injection valve protection control.

The engine control device according to the invention of claim 11 is the invention according to any one of claims 1 to 10,
The vehicle equipped with the engine includes a display unit capable of displaying various information;
During execution of the fuel injection valve protection control, information may be displayed on the display unit to notify an occupant that the idle speed of the engine is increased compared to that during normal idle operation. .

  According to the first aspect of the present invention, in the protection mode cycle, the fuel injection valve protection control raises the idle speed more than in the normal idle operation, thereby promoting combustion in the combustion chamber. Therefore, even if sulfuric acid remains at the nozzle tip of the fuel injection valve between the end of the previous target non-delivery operation and the start of the current protection mode cycle, the protection mode cycle is in progress. The removal of sulfuric acid can be promoted. Therefore, even when a very short driving cycle which is not supposed to be used as a general usage mode is repeated, it is possible to effectively prevent the corrosion of the fuel injection valve due to the retention of sulfuric acid. This makes it easy to maintain the atomization of the fuel injected from the nozzle and, hence, the mixing of air and fuel in the combustion chamber over a long period of time.

  According to the second aspect of the invention, condensation of sulfuric acid occurs at the nozzle tip of the fuel injection valve because the elapsed time from the end of the previous driving cycle to the start of the present protection mode cycle is long. In a situation where there is a relatively high possibility that fuel injection valve protection control is executed, corrosion of the nozzle due to sulfuric acid can be effectively prevented. Conversely, when the elapsed time from the end of the previous driving cycle to the current driving cycle is short and the possibility of sulfuric acid condensation is low, the execution of fuel injection valve protection control is restricted. The waste of fuel can be suppressed.

  According to the third aspect of the invention, the fuel injection valve protection control is performed in the protection mode cycle which is performed at the time of cold where the possibility that sulfuric acid is stagnant at the nozzle tip of the fuel injection valve is relatively high. As a result, corrosion of the nozzle due to sulfuric acid can be effectively prevented. On the contrary, during warm temperatures where the possibility of dew condensation of sulfuric acid is low, the execution of the fuel injection valve protection control is restricted, so that the waste of fuel can be suppressed.

In the invention according to claim 4, according to the temperature of the engine cooling water at the start of the driving cycle, the sulfuric acid in air in the combustion chamber increases as the possibility of the sulfuric acid staying at the nozzle tip increases. As the content of SO ₃ ) tends to increase, the target injection amount serving as the determination reference of the target unattained operation is set higher. Therefore, the next driving cycle is more likely to be set as the protection mode cycle as the possibility that sulfuric acid or sulfuric anhydride remains in the combustion chamber at the end of the driving cycle is higher. As a result, it is possible to prevent the setting of the protection mode cycle and hence the execution of the injection valve protection control from being performed more frequently than necessary, and to improve the efficiency of the protection of the fuel injection valve.

  According to the invention as set forth in claim 5, the setting frequency of the protection mode cycle is avoided until the target non-delivery operation is repeated a predetermined number of times, so that the execution frequency of the injection valve protection control for performing the exceptional idle up. It can be reduced. In addition, when retention of sulfuric acid tends to occur by repeating the target non-delivery operation a predetermined number of times, removal of the sulfuric acid can be achieved by performing the injection valve protection control.

  In the invention according to claim 5, in the driving cycle after the target non-delivery operation has been repeated a predetermined number of times, when the total fuel injection amount reaches the target injection amount, the count number of the target non-delivery operation is reset to zero. Be done. In this case, the driving cycle is likely to end in a state where sulfuric acid or sulfuric anhydride is sufficiently removed from the combustion chamber. In this case, in the next driving cycle, execution of unnecessary injection valve protection control is restricted, and normal engine control can be performed.

  According to the sixth aspect of the invention, since the elapsed time from the end of the previous driving cycle is short, it is started in a situation where the possibility of sulfuric acid condensation at the nozzle tip of the fuel injection valve is low. In the driving cycle, the number of target unachieved operations is not counted up. Therefore, when a short driving cycle is intermittently repeated after a short interval, the number of target non-delivery operations is counted up in a situation where condensation of sulfuric acid is unlikely to occur, and thus, the number of counts is a predetermined number It is possible to avoid unnecessary idle-up being executed by reaching.

  According to the seventh aspect of the invention, in the driving cycle which is started at the warm time when the possibility that the sulfuric acid condensation is generated at the nozzle tip of the fuel injection valve is low, the number of times of target non-delivery operation is increased. It does not happen. Therefore, when the short driving cycle in the warm hour is repeated, the number of times of target non-delivery operation is counted up in a situation where dew condensation of sulfuric acid does not occur easily, and, in turn, unnecessary because the number of counting reaches a predetermined number It is possible to avoid that an idle up is performed.

  According to the invention described in claim 8, when the total fuel injection amount in the protection mode cycle reaches the target injection amount and the sulfuric acid and the sulfuric anhydride are effectively removed from the combustion chamber, the injection valve protection control ends. Be done. As a result, it is possible to suppress the waste of fuel due to the continuation of the idle-up more than necessary while achieving reliable protection of the fuel injection valve.

  According to the invention as set forth in claim 9, when the transmission is in the power transmission impossible state, when the transmission is in the power transmission possible state while achieving early removal of sulfuric acid by execution of the fuel injection valve protection control. Since the idle-up is not performed, a start contrary to the driver's intention from the stopped state is suppressed.

  According to the tenth aspect of the present invention, while the fuel injection valve protection control is being performed, the automatic stop of the engine is prohibited, whereby the removal of sulfuric acid by the combustion in the combustion chamber can be promoted.

  According to the invention as set forth in claim 11, during execution of the fuel injection valve protection control, the display on the display section informs the occupant that the idle speed of the engine is increased compared to that during normal idle operation. it can. Thereby, the discomfort of the passenger | crew by idle up which is not performed by normal control can be reduced.

FIG. 1 is a schematic view of an engine system in an embodiment of the present invention. It is a control system figure of an engine system shown in FIG. It is a flow chart which shows a flow of control operation about setting of a protection mode cycle. It is a flowchart which shows the flow of control operation of a normal mode cycle. It is a flowchart which shows the flow of count mode setting control. 5 is a flowchart showing a flow of target injection amount setting control. It is a flow chart which shows a flow of non-delivery frequency count control. It is a flowchart which shows the flow of control operation of a protection mode cycle. It is a map which shows the correspondence of reference temperature and target injection quantity.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[Engine system]
FIG. 1 shows an engine system 1 mounted on a vehicle. The engine system 1 includes a diesel engine (hereinafter simply referred to as "engine") 2, an intake system 4 for supplying air to the engine 2, and an exhaust system 8 for leading exhaust gas from the engine 2 to the outside of the vehicle.

  The engine 2 has an intake valve 11 which opens when air supplied from the intake system 4 is introduced into the combustion chamber 10, an exhaust valve 12 which opens when exhaust gas is discharged from the combustion chamber 10 after combustion of the mixture. The fuel injection valve 13 directly injects fuel into the combustion chamber 10, the piston 14 reciprocates by combustion of the mixture in the combustion chamber 10, and the crankshaft 15 rotated by the reciprocation of the piston 14 .

  The rotation of the crankshaft 15 output from the engine 2 is shifted by a transmission (not shown) mounted on the vehicle and transmitted to the drive wheel side. The transmission may be an automatic transmission or a manual transmission. The automatic transmission has a power transmission enabled state in which a travel range such as D range and R range is selected by operation of a shift lever, and a power transmission disabled state in which a non-travel range such as P range and N range is selected. It is switched between. The manual transmission is switched by the operation of the change lever between the power transmittable state in which any gear is formed and the neutral state in which the power transmission can not be transmitted.

  The intake system 4 includes an intake passage 20 connected to the combustion chamber 10 via an intake valve 11. An air cleaner 21 for purifying air introduced from the outside, a throttle valve 22 for opening and closing the intake passage 20, and a surge tank 23 for temporarily storing intake air are provided on the intake passage 20 sequentially from the upstream side thereof. There is.

  The exhaust system 8 includes an exhaust passage 30 connected to the combustion chamber 10 via an exhaust valve 12. A post-treatment device 32 is provided on the exhaust passage 30 for post-treatment of the exhaust gas. The post-treatment device 32 includes a plurality of purification devices (not shown) for purifying harmful components in the exhaust gas.

  Specific examples of the purification device included in the post-treatment device 32 include an NSC (NOx Storage Catalyst) device for storing and reducing nitrogen oxides (NOx) in the exhaust gas, hydrocarbons (HC) in the exhaust gas, and monooxidation DOC (Diesel Oxidation Catalyst) device that oxidizes carbon (CO), DPF (Diesel Particulate Filter) device that collects particulate matter such as soot in exhaust gas, nitrogen oxide by reaction with ammonia decomposed from urea Examples thereof include an SCR (Selective Catalytic Reduction) device that reduces (NOx), and a slip catalyst device that oxidizes ammonia that is discharged from the SCR device to render it harmless.

  The engine system 1 further includes an EGR system 50 that recirculates part of the exhaust gas to the intake side. The EGR system 50 includes an EGR passage 51 connecting the exhaust passage 30 and the intake passage 20. The EGR passage 51 is connected upstream of the post-processing device 32 in the exhaust passage 30 and downstream of the throttle valve 22 in the intake passage 20.

  An intermediate portion of the EGR passage 51 is branched into a first EGR passage 51 a and a second EGR passage 51 b. The first EGR passage 51a is provided with an EGR cooler 52 for cooling the gas passing through the first EGR passage 51a, and a first EGR valve 53 for opening and closing the first EGR passage 51a. The second EGR passage 51 b is provided with a second EGR valve 54 that opens and closes the second EGR passage 51 b.

Control system
Various control of the engine system 1 is performed by the control unit 100 shown in FIG. The control unit 100 is configured mainly of, for example, a microprocessor. The control unit 100 includes a central processing unit (CPU), for example, a memory including a RAM and a ROM, and an input / output interface circuit.

  Various external signals are input to the control unit 100. Specific examples of the input signal to the control unit 100 include an engine rotation number sensor 71 that detects the rotation number of the crankshaft 15 as an engine rotation number, an airflow sensor 72 that detects an intake flow rate in the intake passage 20, for example, a surge tank 23 An intake pressure sensor 73 for detecting the intake pressure, a throttle opening degree sensor 74 for detecting the opening degree of the throttle valve 22, a first EGR opening degree sensor 75 for detecting the opening degree of the first EGR valve 53, oxygen of exhaust gas in the exhaust passage 30 The detection signals from the exhaust gas oxygen concentration sensor 76 for detecting the concentration and the engine water temperature sensor 77 for detecting the temperature of the engine cooling water can be mentioned.

  The control unit 100 also includes an ignition switch 78 operated by the driver to start and stop the engine 2, an accelerator opening sensor 79 for detecting an accelerator opening, a vehicle speed sensor 80 for detecting a vehicle speed, and a shift A signal sent from a range sensor 81 that detects the shift range of the automatic transmission selected by the lever is input.

  The above range sensor 81 is used when the transmission mounted on the vehicle is an automatic transmission. In the case of a manual transmission, in place of the range sensor 81, for example, a neutral sensor that detects that the manual transmission is in a neutral state is used.

  The control unit 100 is electrically connected to various devices related to the operation of the engine system 1 including the fuel injection valve 13, the throttle valve 22, the first EGR valve 53, the second EGR valve 54, and the starter 60. The control unit 100 controls various operations of the engine system 1 by outputting control signals to these devices 13, 22, 53, 54, 60.

  Further, the control unit 100 is electrically connected to a display unit 62 provided in the vehicle. The display unit 62 is provided, for example, on an instrument panel or a meter unit. The display unit 62 is configured of, for example, a liquid crystal display. The control unit 100 controls the display of the display unit 62 by outputting a control signal to the display unit 62.

  The control unit 100 includes a protection mode setting unit 101, an idle speed control unit 102, an EGR control unit 103, an idle stop control unit 104, a non-delivery count unit 105, a non-delivery count reset unit 106, a display control unit 107, and storage. The unit 108 is provided.

  The protection mode setting unit 101 sets the protection mode on / off with respect to the control mode in the next driving cycle. The protection mode setting unit 101 sets the driving cycle, which is started when the protection mode is set to ON and satisfies the predetermined condition, to the protection mode cycle, and sets the driving cycle, which is started in other states, to the normal mode cycle. Do.

  The idle speed control unit 102 controls the idle speed of the engine 2. The idle speed control unit 102 executes fuel injection valve protection control (hereinafter, also simply referred to as “injection valve protection control”) that raises the idle speed more than during normal idle operation in the above-described protection mode cycle. The specific control operation of the injection valve protection control will be described later.

  The EGR control unit 103 performs recirculation control (hereinafter also referred to as "EGR control") of the exhaust gas by the EGR system 50. The EGR control unit 103 determines that the temperature of the engine cooling water is equal to or lower than a predetermined temperature (for example, -10 ° C) In this case, EGR cut control is performed to prohibit the recirculation of the exhaust gas by the EGR system 50. The control of the EGR system 50 by the EGR control unit 103 is normally performed also during the execution of the injection valve protection control.

  The idle stop control unit 104 performs idle stop control to automatically stop the engine 2 when a predetermined automatic stop condition is satisfied. The automatic stop condition includes a plurality of conditions, and when all the conditions are satisfied, the automatic stop condition is satisfied. Specific examples of various conditions constituting the automatic stop condition are that the shift range of the automatic transmission is D range or N range, the accelerator is fully closed, the brake switch is on, and the remaining battery capacity is The predetermined amount or more, acceleration to a predetermined vehicle speed or more at least once after the previous idle stop control is canceled, and the like can be mentioned. The idle stop control unit 104 does not execute the idle stop control during execution of the injection valve protection control even if the automatic stop condition is satisfied.

  The number of times of non-delivery count unit 105 counts the number of target non-delivery operations (hereinafter also referred to as “the number of non-delivery times”) in which the total fuel injection amount of the engine 2 in one driving cycle does not reach a predetermined target injection amount. . Counting up by the non-delivery count part 105 can be executed only in the normal mode cycle. When the number of times of non-delivery counted by the number of times of non-delivery counting unit 105 becomes equal to or more than a predetermined number of times, the protection mode is set to ON by the above-mentioned protection mode setting unit 101.

  When the total fuel injection amount of the engine 2 reaches the target injection amount, the non-delivery count reset unit 106 resets the number of counts by the non-delivery count counting unit 105 to zero. The reset by the non-delivery count reset unit 106 can be performed in any of the normal mode cycle and the protection mode cycle.

  The display control unit 107 controls the display of the display unit 62 described above. The display control unit 107 causes the display unit 62 to display various information according to the driving state and the operation of the occupant.

  When the above-described injection valve protection control is being performed, the display control unit 107 notifies the passenger that the injection valve protection control is being performed or that the cleaning of the fuel injection system is being performed. The information is displayed on the display unit 62. At this time, it is preferable that the information displayed on the display unit 62 includes that the idle speed of the engine 2 is increased (idle up) as compared to that during normal idle operation. Such information is displayed, for example, in the form of characters, but instead of or in addition to the display of characters, display may be performed by lighting of a warning light or the like.

  The storage unit 108 stores various information related to control of the engine system 1. In the present embodiment, specific examples of the information stored in the storage unit 108 include the contents set by the protection mode setting unit 101, the total fuel injection amount of the engine 2 in one driving cycle, and the target injection amount of the total fuel injection amount. And the number of counts by the non-delivery count unit 105.

[Protect mode cycle setting]
An example of control operation regarding setting of a protection mode cycle by the protection mode setting unit 101 will be described with reference to a flowchart shown in FIG.

  The control operation shown in FIG. 3 is started when the ignition switch 78 is turned on. When the current driving cycle is started by the on operation of the ignition switch 78, it is determined in step S1 whether the setting of the protection mode at the end of the previous driving cycle is on or off.

  As a result of the determination in step S1, when the protection mode is set to off, in step S5, the current driving cycle is set to the normal mode cycle, and the engine system 1 is controlled in the normal mode. The specific control operation in the normal mode will be described later with reference to FIG.

  On the other hand, when the protection mode is set to ON as a result of the determination in step S1, the determinations in steps S2 and S3 are performed.

  In step S2, it is determined whether an elapsed time from the end of the previous driving cycle to the start of the current driving cycle (hereinafter, also referred to as a "soak time") is a predetermined time or more. The "predetermined time" in step S2 is set to, for example, 30 minutes.

  In step S3, it is determined whether the temperature of the engine coolant at the start of the current driving cycle is less than a predetermined temperature. The "predetermined temperature" in step S3 is set to, for example, 50.degree.

  As a result of the determination in step S2, if the soak time is less than a predetermined time, and if the cooling water temperature is equal to or higher than the predetermined temperature as a result of the determination in step S3, the protection mode is set to ON. The current driving cycle is set to the normal mode cycle (step S5).

  On the other hand, as a result of the determination in steps S2 and S3, when the soak time is equal to or longer than the predetermined time and the coolant temperature is less than the predetermined temperature, the current driving cycle is set to the protection mode cycle in step S4, The engine system 1 is controlled in the mode. A specific control operation in the protection mode will be described later with reference to FIG.

  In the present embodiment, at the start of the protection mode cycle, the protection mode is set to ON, the soak time is relatively long, and the engine 2 is in the cooled state. In this state, it is relatively likely that condensation of sulfuric acid is occurring in the combustion chamber 10 of the engine 2. Therefore, in the present embodiment, removal of sulfuric acid from the combustion chamber 10 is promoted by executing injection valve protection control described later in the protection mode cycle.

  On the other hand, the normal mode cycle is started under an environment where the possibility of sulfuric acid condensation is relatively low. Therefore, in the normal mode cycle, the engine system 1 is controlled in the normal mode without executing the injection valve protection control.

[Engine control in normal mode]
An example of the control operation of the engine system 1 in the normal mode will be described mainly with reference to the flowchart shown in FIG.

  In the normal mode cycle, on / off setting of the protection mode required for control in the next driving cycle (steps S42 and S47 in FIG. 7) is performed.

  In the present embodiment, the protection mode is set to ON when the target non-delivery operation that the total fuel injection amount of the engine 2 in one driving cycle does not reach the predetermined target injection amount is repeated a predetermined number of times. Therefore, in the normal mode cycle in the present embodiment, a later-described number-of-non-delivery count control (see step S17 in FIG. 4 and FIG. 7) for counting the number of target non-delivery operation (in-delivery number) is executed.

  Further, in the normal mode cycle in the present embodiment, target injection amount setting control described later (see step S12 in FIG. 4 and FIG. 6) for setting the target injection amount, and count mode in which count up of the number of unreached The count mode setting control (see step S11 in FIG. 4 and FIG. 5), which will be described later, is performed.

  The specific flow of the control operation in the normal mode cycle will be described according to the flowchart shown in FIG.

  First, in steps S11 and S12, count mode setting control and target injection amount setting control are executed. Specific control operations of the count mode setting control (step S11) and the target injection amount setting control (step S12) will be described later.

  Subsequently, at step S13, the engine 2 is started by the starter 60 (see FIG. 2). When the engine 2 is started, the engine system 1 is normally controlled in step S14. In the normal control of step S14, various controls such as idle stop control, EGR control, and idle up control at cold time are normally performed according to the operating state. The normal control of step S14 is continued until the end of the normal mode cycle.

  Further, while the engine 2 is being driven, the total fuel injection amount of the engine 2 in the current driving cycle is calculated by integrating the fuel injection amount in step S15.

  In step S16, it is determined whether the ignition switch 78 has been turned off. As a result of the determination in step S16, the normal control (step S14) and the calculation of the total fuel injection amount (step S15) are continued until the ignition switch 78 is turned off.

  As a result of the determination in step S16, when the ignition switch 78 is turned off, the engine 2 is stopped in step S18 after passing-through count control (step S17) described later. The specific control operation of the non-delivery count control (step S17) will be described later.

[Count mode setting control]
An example of control operation of count mode setting control (see step S11 of FIG. 4) will be described with reference to the flowchart shown in FIG.

  In the count mode setting control, the determination of step S21 related to the soak time and the determination of step S22 related to the coolant temperature at the start are performed.

  In step S21, as in step S2 of FIG. 3, it is determined whether the soak time is equal to or longer than a predetermined time. Although "predetermined time" in step S21 is set to, for example, the same time as "predetermined time" in step S2 of FIG. 3, it may be set to a different time.

  In step S22, as in step S3 of FIG. 3, it is determined whether the coolant temperature at startup is less than a predetermined temperature. The “predetermined temperature” in step S22 is set, for example, to the same temperature as the “predetermined temperature” in step S3 of FIG. 3, but may be set to a different temperature.

  As a result of the determination in step S21, if the soak time is less than a predetermined time, and if the cooling water temperature is equal to or higher than the predetermined temperature as a result of the determination in step S22, the count mode is set to off in step S24. In the driving cycle in which the count mode is set to off, even if the target non-delivery operation is performed, the non-delivery count is not counted up in the non-delivery count control (see step S17 in FIG. 4 and FIG. 7) described later.

  On the other hand, if it is determined in step S21 and S22 that the soak time is equal to or longer than the predetermined time and the coolant temperature is less than the predetermined temperature, the count mode is set to ON in step S23. When the count mode is set to ON, count-up of the number of non-delivery is permitted in non-delivery count control described later (refer to step S17 of FIG. 4 and FIG. 7).

[Target injection amount setting control]
An example of the control operation of the target injection amount setting control (see step S12 in FIG. 4) will be described with reference to the flowchart shown in FIG.

  First, in step S31, it is determined whether or not the one or more non-delivery count has already been counted by the non-delivery count counting unit 105 at the start of the current driving cycle.

  As a result of the determination in step S31, when the number of unreached counted by uncounted number counting unit 105 is zero, the temperature of the coolant water of engine 2 at the start of the current driving cycle is set as the reference temperature in step S32. Ru. The reference temperature referred to here is the coolant temperature which is the reference of setting of the target injection amount.

  On the other hand, as a result of the determination in step S31, when the number of unreached times counted by the unreached number counting unit 105 is counted, in step S32, the coolant temperature at the start of the current driving cycle and the previous driving cycle The starting coolant temperature is compared. In the subsequent step S35, as a result of the comparison in step S34, the lower cooling water temperature is set to the reference temperature. That is, in step S35, the lowest coolant temperature among the coolant temperatures at the start of a plurality of driving cycles from the driving cycle in which the first count is performed to the current driving cycle is set as the reference temperature. .

  When the reference temperature is set in step S32 or step S35, a target injection amount (target value of total fuel injection amount) F is set based on the set reference temperature in step S33. The setting of the target injection amount F in step S33 is performed based on, for example, the map shown in FIG.

  In the setting example shown in FIG. 9, when the reference temperature is equal to or higher than the predetermined first temperature T1, the target injection amount F is set to zero. The first temperature T1 is set to, for example, the same temperature (for example, 50 ° C.) as the “predetermined temperature” in step S22 of FIG. When the target injection amount F is set to zero, the driving cycle can not be the target non-delivery operation, so the number of non-delivery times in the driving cycle is not counted up.

  When the reference temperature is less than the first temperature T1, the target injection amount F is basically set higher as the reference temperature is lower. More specifically, in the first temperature range from the second temperature T2 lower than the first temperature T1 to the first temperature T1, a proportional relationship with a relatively gentle slope is established, and the first temperature range lower than the second temperature T2 In the second temperature range from the third temperature T3 to the second temperature T2, a proportional relationship with a steeper slope is established than in the first temperature range. The second temperature T2 is set to, for example, 25 ° C., and the third temperature T3 is set to, for example, -10 ° C.

  The EGR control may be executed when the coolant temperature of the engine 2 is higher than the third temperature T3, but the EGR cut control is executed when the coolant temperature of the engine 2 is equal to or lower than the third temperature T3. That is, the second temperature range from the third temperature T3 to the second temperature T2 is a low temperature range in which the EGR control can be performed, and is a disadvantageous temperature range with respect to the removal of the sulfuric acid from the combustion chamber 10. Therefore, the target injection amount F is set relatively high in this second temperature range.

  In the third temperature range from the fourth temperature T4 to the third temperature T3 which is lower than the third temperature T3, the target injection amount F is set to be lower as the reference temperature is lower, exceptionally. In the fourth temperature range lower than the fourth temperature T4, the target injection amount F is set higher as the reference temperature is lower. In the fourth temperature range, a proportional relationship is established that is steeper than the first temperature range and gentler than the second temperature range. The fourth temperature T4 is set to, for example, -15 ° C.

[Count on number of times not delivered]
An example of the control operation of the non-delivery count control (see step S17 in FIG. 4) will be described with reference to the flowchart shown in FIG.

  As described above, the non-delivery count control is performed at the end of the normal mode cycle. In the non-delivery count control, first, in step S41, it is determined whether the total fuel injection amount in the current driving cycle is equal to or more than the target injection amount F described above.

  As a result of the determination in step S41, when the target unachieved operation in which the total fuel injection amount is less than the target injection amount F, in step S44, the count mode setting control (see step S11 in FIG. 4 and FIG. 5) is performed. It is determined whether the count mode is set to on.

  As a result of the determination in step S44, if the count mode is on, the non-delivery count unit 105 performs count-up to increase the count of the non-delivery count by one (step S45). The current normal mode cycle ends without being counted up.

  When the number of non-delivery is counted up in step S45, it is determined in step S46 whether the number of non-delivery counted by the number-of-non-delivery counting unit 105 is equal to or more than a predetermined number. The "predetermined number of times" in step S46 is set to, for example, five times.

  As a result of the determination in step S46, if the number of times of non-delivery is less than the predetermined number of times, the current normal mode cycle is ended while the protection mode is set to OFF (step S48). In this case, the next driving cycle is also set to the normal mode cycle.

  On the other hand, as a result of the determination in step S46, if the number of non-delivery times is equal to or more than the predetermined number, the protection mode is set to ON by the protection mode setting unit 101 in step S47. In this case, the next driving cycle is set to the protection mode cycle if the predetermined condition (see steps S2 and S3 in FIG. 3) is satisfied (see step S4 in FIG. 3).

  When the total fuel injection amount is equal to or greater than the target injection amount F as a result of the determination in step S41, the protection mode is set to OFF (step S42), and the unreached number reset unit 106 resets the unreached number to zero. (Step S43). As a result, the next driving cycle is set to the normal mode cycle. In this case, in the normal mode cycle of this time, a sufficient amount of combustion is performed to reliably remove the sulfuric acid from the combustion chamber 10. Therefore, even if the injection valve protection control is not performed in the next driving cycle. The corrosion of the fuel injection valve 13 hardly occurs.

[Engine control in protected mode]
An example of the control operation of the engine system 1 in the protection mode will be described mainly with reference to the flowchart shown in FIG.

  In the protection mode cycle, the injection valve protection control (step S56) and the on / off setting of the protection mode (steps S61 and S64) are performed according to the operating state. The flow of specific control operation in the protection mode cycle will be described below.

  First, at step S51, target injection amount setting control is performed. The target injection amount setting control of step S51 is performed in the same manner as the target injection amount setting control (see step S12 of FIG. 4, FIG. 6, and FIG. 9) in the normal mode cycle described above.

  Subsequently, at step S52, the engine 2 is started by the starter 60 (see FIG. 2). In addition, while the engine 2 is being driven, the total fuel injection amount of the engine 2 in the current driving cycle is calculated by integrating the fuel injection amount in step S53.

  In step S54, it is determined whether the shift range of the automatic transmission is a non-traveling range. The non-driving range here is, for example, a stop range (P range) and a neutral range (N range). In the case of a manual transmission, it is determined in step S54 whether or not the neutral state is established.

  If it is determined in step S54 that the shift range is the travel range (for example, D range and R range), normal engine control (step S58) is performed during this time. In this case, since the idle-up control (step S56) described later is not performed, the start of the vehicle in a state contrary to the driver's intention from the stopped state is suppressed. Further, in this case, by promoting combustion in the combustion chamber 10 while the vehicle is traveling, it is possible to promote the removal of sulfuric acid from the nozzle tip of the fuel injection valve 13.

  On the other hand, if it is determined in step S54 that the shift range is the non-traveling range (for example, P range and N range), the total fuel injection amount after engine start in step S52 is set in step S51 in step S55. It is determined whether it is less than the target injection amount F.

  If it is determined in step S55 that the injection amount is smaller than the target injection amount F, the injection valve protection control by the idle speed control unit 102 is executed in step S56.

  In the injection valve protection control of step S56, idle operation (idle up control) is performed in which the idle rotational speed is increased as compared with normal idle operation. By promoting combustion in the combustion chamber 10 by such idle-up control, removal of sulfuric acid from the nozzle tip of the fuel injection valve 13 can be promoted.

  The idle rotation speed after rising by the injection valve protection control is, for example, a rotation speed equal to the upper limit value of the idle rotation speed in normal idle-up control performed at cold time. The idle speed during normal idle operation is, for example, 800 rpm, and the idle speed under the injection valve protection control is, for example, 1500 rpm.

  When the injection valve protection control of step S56 is executed, the idle stop control is prohibited by the idle stop control unit 104. As a result, driving of the engine 2 is continued, whereby the removal of sulfuric acid by combustion in the combustion chamber 10 can be promoted.

  Further, when the injection valve protection control of step S56 is executed, the EGR control by the EGR control unit 103 is performed as usual. As a result, while the fuel injection valve 13 is protected by the injection valve protection control, the reduction effect of nitrogen oxides (NOx) in the exhaust gas by the EGR control can be favorably exhibited.

  Furthermore, during the execution of the injection valve protection control, in step S57, the display unit 62 displays information for notifying the occupant that the idle up is performed for protection or cleaning of the fuel injection valve 13. . As a result, it is possible to reduce the discomfort of the occupant with respect to the execution of the idle up.

  In the next step 59, it is determined whether the ignition switch 78 has been turned off. If it is determined in step S59 that the ignition switch 78 has not been turned off, the process returns to step S53. In this case, the injection valve protection control of step S56 or the normal engine control of step S58 is selectively executed in accordance with the determination results of steps S54 and S55.

  As a result, during driving of the engine 2, when the shift range is the non-traveling range until the total fuel injection amount reaches the target injection amount F, the injection valve protection control (step S56) is executed. As described above, since the target injection amount F is set to be higher as cold time (see FIG. 9), the injection valve protection control (step S56) becomes easier to be executed as cold time.

  When the shift range is switched to the travel range while the total fuel injection amount reaches the target injection amount F while driving the engine 2, the injection valve protection control (step S56) is interrupted, and Engine control (step S58) is performed.

  Thereafter, when the total fuel injection amount is returned to the non-traveling range before reaching the target injection amount F, the injection valve protection control (step S56) is resumed. On the other hand, when the total fuel injection amount reaches the target injection amount F while normal engine control (step S58) is being performed in the travel range, the ignition switch 78 is turned off even if the fuel injection amount is subsequently returned to the non-traveling range. Normal engine control (step S58) is continued until it is done.

  As a result of the determination in step S59, when the ignition switch 78 is turned off, it is again determined in step S60 whether the total fuel injection amount is less than the target injection amount F.

  As a result of the determination in step S60, when the total fuel injection amount is equal to or more than the target injection amount F, the protection mode is set to OFF (step S61), and the unreached number reset unit 106 resets the unreached number to zero. (Step S62). As a result, the next driving cycle is set to the normal mode cycle. In this case, since a sufficient amount of combustion is performed to reliably remove the sulfuric acid from the combustion chamber 10 in the present protection mode cycle, even if the injection valve protection control is not executed in the next driving cycle. The corrosion of the fuel injection valve 13 hardly occurs.

  On the other hand, if it is determined in step S60 that the total fuel injection amount is less than the target injection amount F, the protection mode cycle is ended while the protection mode is set to ON (step S64). In this case, when the next driving cycle is set again to the protection mode cycle, the injection valve protection control is executed again, so that the fuel injection valve 13 can be reliably protected.

  Thereafter, in step S63, the fuel supply from the fuel injection valve 13 to the combustion chamber 10 is stopped, and the engine 2 is stopped.

[Function effect]
As described above, in the present embodiment, the control in the normal mode (see FIG. 4) is performed unless the target non-delivery operation at cold time is repeated a predetermined number of times, so the injection valve protection control (step in FIG. 8) S56) can be avoided from being executed frequently.

  In addition, when retention of the sulfuric acid is likely to occur by repeating the target non-delivery operation at cold time a predetermined number of times, the injection valve protection control (see step S56 in FIG. 8) is performed in the control in the protection mode. Thus, the sulfuric acid can be reliably removed. Therefore, the corrosion of the fuel injection valve 13 due to the retention of sulfuric acid can be effectively prevented. As a result, the atomization of the fuel injected from the fuel injection valve 13 and hence the mixing of the air and the fuel in the combustion chamber 10 can be easily maintained over a long period of time.

  When the total fuel injection amount reaches the target injection amount F in the driving cycle after the target non-achievement operation is repeated a predetermined number of times, there is a high possibility that sulfuric acid or sulfuric anhydride is sufficiently removed from the combustion chamber 10 . In this case, since the count number of the target non-delivery operation is reset to zero (see step S43 in FIG. 7 and step S62 in FIG. 8), control in the normal mode is performed at least a predetermined number of driving cycles from the next time. (See FIG. 4). Thereby, it is possible to suppress the waste of fuel due to the execution of unnecessary injection valve protection control.

  Further, according to the present embodiment, in the driving cycle started under a situation where the possibility of dew condensation of sulfuric acid is low due to the short soak time or the cold time, the target non-delivery operation is not performed. The number of times is not counted up (see step S24 in FIG. 5). Therefore, it is possible to suppress the execution frequency of the injection valve protection control from rising more than necessary due to the counting up more than necessary.

  As mentioned above, although the present invention was described with the above-mentioned embodiment, the present invention is not limited to the above-mentioned embodiment.

  For example, in the embodiment described above, the condition that the protection mode cycle is set (step S4 in FIG. 3) requires that the soak time is equal to or longer than a predetermined time (step S2 in FIG. 3). Although the example including being below the predetermined temperature (step S3 in FIG. 3) has been described, one or both of these conditions may be excluded from the setting conditions of the protection mode cycle. Also, other conditions may be included in the setting conditions of the protection mode cycle.

  In the above-described embodiment, the condition that the count mode is set to ON (step S23 in FIG. 5) is that the soak time is equal to or longer than the predetermined time (step S21 in FIG. 5) Although the example in which the temperature is less than the predetermined temperature (step S22 in FIG. 5) is described, one or both of these conditions may be excluded from the setting conditions of the protection mode cycle. Also, other conditions may be included in the setting conditions of the protection mode cycle.

  Furthermore, in the above-mentioned embodiment, although an example in which the protection mode is set to ON when the unreached operation is repeated a plurality of times has been described, the protection mode is set to ON when one undelivery operation is performed. It may be done.

  In the above embodiment, the present invention has been described by taking a diesel engine using light oil as an example, but the present invention can corrode the tip of the nozzle of the fuel injection valve at low temperatures, such as gasoline containing sulfur components. The present invention is applicable to various engines in which a fuel containing a component is used.

  As described above, according to the present invention, corrosion of the fuel injection valve of the engine due to retention of sulfuric acid is also effective even when a very short driving cycle which is not supposed to be used as a general usage mode is repeated. It is possible to be suitably used in the field of production technology of engines using fuels containing sulfur components and vehicles equipped with such engines because it can be prevented.

DESCRIPTION OF SYMBOLS 1 engine system 2 engine 10 combustion chamber 13 fuel injection valve 15 crankshaft 50 EGR system 62 display part 77 engine water temperature sensor 78 ignition switch 81 range sensor 100 control unit (control device)
101 Protection mode setting unit (protection mode setting unit)
102 Idle speed control unit (idle speed control means)
103 EGR control unit 104 idle stop control unit (automatic stop control means)
105 Unreached count part (unmissed count means)
106 Unreached number reset unit (reset means)
107 display control unit 108 storage unit

Claims (11)

An engine control device comprising: a fuel injection valve for supplying fuel to a combustion chamber of an engine; and idle speed control means for controlling an idle speed of the engine,
Protects the next driving cycle when target non-delivery operation is performed where the total fuel injection amount in one driving cycle from when the driving of the engine is started to when it stops is less than the predetermined target injection amount Equipped with protection mode setting means for setting mode cycles,
The engine control device according to claim 1, wherein the idle speed control means executes fuel injection valve protection control to increase the idle speed of the engine in the protection mode cycle more than during normal idle operation.   The engine according to claim 1, wherein the protection mode setting means regulates setting of the driving cycle started before the end of the previous driving cycle until a predetermined time has elapsed from the protection mode cycle. Control device.   The protection mode setting means regulates setting of the driving cycle started when the temperature of the engine coolant is equal to or higher than a predetermined temperature in the protection mode cycle. The control device of the described engine.   The engine control device according to any one of claims 1 to 3, wherein the target injection amount is set in accordance with a temperature of engine cooling water at the start of a driving cycle. An undelivered number counting means for counting the number of times of target unachieved operation
Reset means for resetting the number of counts of the target non-delivery operation to zero when the total fuel injection amount reaches the target injection amount;
5. The protection mode setting means restricts setting of the next driving cycle to the protection mode cycle until the target non-delivery operation is counted a predetermined number of times. The control device of the engine given in any 1 paragraph.   The non-delivery count counting means counts up the number of the non-targeted operation only when the non-targeted operation is performed in a driving cycle started a predetermined time or more after the end of the previous driving cycle. The engine control device according to claim 5, wherein:   The non-delivery count counting means counts up the number of the non-targeted operation only when the non-targeted operation is performed in a driving cycle started with the temperature of the engine coolant being lower than a predetermined temperature. The control apparatus of the engine according to claim 5 or 6, characterized in that:   8. The fuel injection valve protection control according to claim 1, wherein the idle speed control means ends the fuel injection valve protection control when the total fuel injection amount in the protection mode cycle reaches the target injection amount. The control device of the engine given in any 1 paragraph. The vehicle equipped with the engine includes a transmission that changes the rotation of the engine and outputs the same to the drive wheels, and switching means for switching the transmission between a power transmittable state and a power transmittable state.
9. The engine according to any one of claims 1 to 8, wherein the idle speed control means interrupts the fuel injection valve protection control when the transmission is in a power transfer enable state. Control device. An automatic stop control means for automatically stopping the engine when a predetermined engine stop condition is satisfied;
The engine control according to any one of claims 1 to 9, wherein the automatic stop control means does not automatically stop the engine during execution of the fuel injection valve protection control. apparatus. The vehicle equipped with the engine includes a display unit capable of displaying various information;
During execution of the fuel injection valve protection control, information may be displayed on the display unit to notify an occupant that the idle speed of the engine is increased compared to that during normal idle operation. The engine control device according to any one of claims 1 to 10.

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