JP2007056702A - Trouble determination device for high-pressure fuel feeder of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately determine the trouble of a relief valve returning a fuel from a delivery pipe to a fuel tank during the operation of an internal combustion engine without producing a trouble in a fuel injection means. <P>SOLUTION: An engine ECU performs a program including a step (S100) for detecting an engine cooling water temperature THW, a step (S130) for detecting the nozzle hole temperature TINJ of an injector for direct injection when the THW is lower than a threshold T (0) (YES in S110) and brought in an idle operating state (YES in S120), and a step for stopping fuel injection from the injector for direct injection (S150) when the TINJ is lower than the threshold T (1) (YES in S140) to stop the operation of a high-pressure fuel pump (S160), detecting a fuel pressure Pr in the high-pressure delivery pipe (S190) when a predetermined time is elapsed after an open instruction signal is output to a solenoid relief valve, and determining that the solenoid relief valve is defective when Pr is equal to or higher than the threshold Pr (0) (NO in S200). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention injects fuel into an intake passage or an intake port in addition to an internal combustion engine having a fuel injection means (in-cylinder injector) for injecting fuel at a high pressure into the cylinder. In particular, the present invention relates to an abnormality determination device for an electromagnetic relief valve provided in a high-pressure fuel supply device for an internal combustion engine, which includes a fuel injection means (intake passage injection injector).

  In general, in an automobile engine, fuel is supplied from a fuel tank to an engine (internal combustion engine) via a fuel pump and a fuel pipe, and the fuel is injected into the engine via an injector.

  A first fuel injection valve (in-cylinder injector) for injecting fuel into a combustion chamber of a gasoline engine, and a second fuel injection valve (injector for injector injection) for injecting fuel into an intake passage And an engine that injects fuel between the in-cylinder injector and the intake manifold injector in accordance with the engine speed and the load on the internal combustion engine. Further, a direct engine including only a fuel injection valve (in-cylinder injector) for injecting fuel into a combustion chamber of a gasoline engine is also known. In a high-pressure fuel system including an in-cylinder injector, fuel whose pressure has been increased by a high-pressure fuel pump is supplied to the in-cylinder injector via a high-pressure delivery pipe. High pressure fuel is injected into the combustion chamber of the cylinder.

  In such an engine, it is necessary to prevent vapor from being generated in the fuel in the fuel pipe in order to improve the high-temperature restartability when the engine is started. Therefore, in a conventional fuel injection control device for an engine, a check valve is provided on the discharge port side of the fuel pump to maintain a high fuel pressure without reducing the residual fuel pressure in the high-pressure delivery pipe even when the engine is stopped. It is configured as follows.

  However, if the fuel pressure in the high-pressure delivery pipe is kept high while the engine is stopped, fuel may leak from the injector into the intake pipe. The fuel pressure maintained at a high pressure even when the engine is stopped decreases to an atmospheric pressure equivalent value (= 0.1 [MPa]) in about 60 minutes, but the gasoline leakage during that period is about 20 mcc per fuel pipe. Also reach.

  Such a fuel leak causes an increase in unburned HC in the exhaust gas at the next engine start. The amount of HC emission at the start-up may become very large within a time of about 1 second. In addition, since the amount of fuel leakage from the injector cannot be managed, the exhaust gas component at the time of engine start varies.

  Furthermore, the fuel leaking into the intake pipe also increases the fuel evaporation gas from the automobile. Such a state has become an unacceptable level with respect to exhaust gas regulations that are becoming increasingly strict in recent years.

  Under such circumstances, when the engine is stopped, the fuel in the high-pressure delivery pipe is returned to the fuel tank, and the residual fuel pressure in the high-pressure delivery pipe is quickly reduced so as not to maintain a high fuel pressure. Composed. For this purpose, a fuel bypass valve (relief valve) is provided in the high-pressure delivery pipe. In addition, a fuel bypass valve (relief valve) is provided in the delivery pipe in order to prevent deterioration of exhaust emission even in an engine including only the intake manifold injector, including the following patent documents.

Japanese Patent Application Laid-Open No. 5-280404 (Patent Document 1) discloses a fuel injection device for an engine that performs direct injection and manifold injection. In this engine fuel injection device, a fuel pump that is driven by an output shaft of the engine via a timing belt is disposed in the branch fuel supply passage. On the downstream side of the fuel pump, there are provided a relief passage for relieving the fuel to the branch fuel supply passage and a relief valve for sending the fuel discharged from the fuel pump to the relief passage in response to a control signal from the control circuit. ing. The direct injection valve is connected to a fuel return passage for returning the fuel not injected into the working chamber to the fuel tank.
JP-A-5-280404

  However, in Patent Document 1 described above, there is no mention of abnormality determination of the relief valve. The relief valve must be closed when the high-pressure fuel system (direct injection system of Patent Document 1) is operating (when fuel is being injected). For this reason, when the high-pressure fuel system is operating, the relief valve cannot make an abnormality determination. On the other hand, when the operation of the high-pressure fuel system is appropriately stopped, an open signal is transmitted to the relief valve, and the relief valve is judged abnormal by confirming that the high-pressure fuel is sent to the relief passage, an in-cylinder injector There is a problem that fuel injection from (the first fuel injection valve of Patent Document 1) stops, the tip of the in-cylinder injector becomes hot, and deposits accumulate in the injection holes.

  The present invention has been made to solve the above-described problems, and its object is to return the fuel from the delivery pipe to the fuel tank during operation of the internal combustion engine without causing abnormality in the fuel injection means. An object of the present invention is to provide an abnormality determination device for a high-pressure fuel supply apparatus for an internal combustion engine, which can accurately determine abnormality of a relief valve.

  An abnormality determination device according to a first aspect of the present invention is an internal combustion engine comprising a first fuel injection means for injecting fuel into a cylinder and a second fuel injection means for injecting fuel into an intake passage. The abnormality of the high pressure fuel supply device is determined. In this internal combustion engine, control is performed so that the fuel is injected between the first fuel injection means and the second fuel injection means based on the conditions required for the internal combustion engine. The high-pressure fuel supply device includes a delivery pipe that supplies the fuel supplied from the fuel tank to the first fuel injection means, and a relief valve that switches the delivery pipe and the fuel tank between a communication state and a non-communication state. The abnormality determination device includes control means for controlling the relief valve and determination means for determining abnormality of the relief valve. The determination means detects the pressure of the fuel in the delivery pipe after controlling the relief valve so that the first fuel injection means is deactivated when the predetermined condition for the internal combustion engine is satisfied, and the communication state is established. And means for determining an abnormality of the relief valve based on the detected fuel pressure.

  According to the first invention, for example, the condition that deposits do not accumulate in the nozzle hole of the first fuel injection means is satisfied, and the condition that a good combustion state can be maintained with only the second fuel injection means is satisfied. Then, the fuel injection from the first fuel injection means is stopped, the fuel is injected only by the second fuel injection means, and the relief valve is opened. At this time, if the fuel pressure in the delivery pipe does not decrease, it can be determined that the electromagnetic relief valve is abnormal. As a result, a high-pressure fuel supply device for an internal combustion engine that can accurately determine abnormality of a relief valve that returns fuel from a delivery pipe to a fuel tank during operation of the internal combustion engine without causing abnormality in the fuel injection means. An abnormality determination device can be provided.

  In the abnormality determination device according to the second invention, in addition to the configuration of the first invention, the predetermined condition for the internal combustion engine is that the temperature of the first fuel injection means is equal to or lower than the predetermined temperature. It is a condition.

  According to the second invention, when the temperature of the first fuel injection means is equal to or lower than a predetermined temperature, no deposit is deposited in the injection hole. Therefore, it is possible to accurately determine the abnormality of the relief valve that returns the fuel from the delivery pipe to the fuel tank during operation of the internal combustion engine without causing the first fuel injection means to fail.

  In the abnormality determination device according to the third invention, in addition to the configuration of the first or second invention, the condition predetermined for the internal combustion engine is a condition that the operation state of the internal combustion engine is an idle operation state.

  According to the third aspect of the invention, in the idling state (light load), the temperature of the internal combustion engine is low and the temperature of the first fuel injection means is equal to or lower than a predetermined temperature, and no deposit accumulates in the injection hole. In the idling state (light load), a good combustion state can be maintained even if fuel is injected only from the second fuel injection means. Furthermore, even if fuel is injected only from the second fuel injection means, a necessary driving force (driving force for a light load) can be output. Therefore, the abnormality of the relief valve for returning the fuel from the delivery pipe to the fuel tank is accurately determined during the operation of the internal combustion engine without maintaining the operation state of the internal combustion engine and causing the first fuel injection means to fail. be able to.

  In the abnormality determination device according to the fourth invention, in addition to the configurations of the first to third inventions, the determination means determines that the relief valve is abnormal if the detected fuel pressure is equal to or higher than a predetermined pressure. Means for determining that there is.

  According to the fourth invention, even if the fuel injection by the first fuel injection means is stopped and the relief valve is opened, if the pressure of the fuel in the delivery pipe is equal to or higher than a predetermined pressure, the relief valve It can be determined that the abnormality does not open.

  In the abnormality determination device according to the fifth aspect of the invention, in addition to the configurations of the first to fourth aspects of the invention, when the internal combustion engine is stopped, the control means is in a non-communication state during operation of the internal combustion engine. Means are included for controlling the relief valve to be in communication.

  According to the fifth aspect of the invention, when the internal combustion engine is stopped, the delivery pipe and the fuel tank are in communication with each other to sufficiently reduce the pressure of the fuel in the delivery pipe. For this reason, it is possible to avoid the fuel leakage from the first fuel injection means and various problems caused by the fuel leakage.

  In the abnormality determination device according to the sixth invention, in addition to the configurations of the first to fifth inventions, the first fuel injection means is an in-cylinder injector, and the second fuel injection means is the intake air It is an injector for channel injection.

  According to a sixth aspect of the present invention, in the internal combustion engine for sharing the injected fuel by separately providing the in-cylinder injector that is the first fuel injection means and the intake passage injection injector that is the second fuel injection means, The abnormality of the relief valve for returning the fuel from the delivery pipe to the fuel tank can be accurately determined without causing an abnormality in the internal injection injector.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  FIG. 1 shows an engine fuel supply system 10 according to an embodiment of the present invention. This engine is a V-type 8-cylinder gasoline engine, and includes an in-cylinder injector 110 that injects fuel into the cylinder of each cylinder, and an intake passage injector 120 that injects fuel into the intake passage of each cylinder. Have The present invention is not limited to such an engine, and may be a V-type 6-cylinder engine, an in-line 4-cylinder engine, an in-line 6-cylinder engine, or the like. Furthermore, the number of high-pressure fuel pumps is not limited to two.

  As shown in FIG. 1, the fuel supply system 10 is provided in a fuel tank, and is driven by a feed pump 100 that supplies fuel at a low pressure (pressure regulator pressure of about 400 kPa) and a first cam 210. The high-pressure fuel is supplied to the second high-pressure fuel pump 300 driven by the second cam 310 and the in-cylinder injector 110 that are different in discharge phase from the first high-pressure fuel pump 200 and the first cam 210. High pressure delivery pipe 112 provided for each of the left and right banks, four in-cylinder injectors 110 for each of the left and right banks provided in the high pressure delivery pipe 112, and an intake passage injection injector 120. A low pressure delivery pipe 122 provided for each of the left and right banks for supplying fuel, and the low pressure delivery pipe 12 And a left and right banks intake manifold injectors 120 for each of the four provided.

  The discharge port of the fuel tank feed pump 100 is connected to a low-pressure supply pipe 400, and the low-pressure supply pipe 400 branches into a first low-pressure delivery communication pipe 410 and a pump supply pipe 420. The first low-pressure delivery communication pipe 410 becomes a second low-pressure delivery communication pipe 430 on the downstream side of the branch point with the low-pressure delivery pipe 122 of one bank of the V-shaped bank, and the low-pressure delivery pipe 122 of the other bank. It is connected to the.

  The pump supply pipe 420 is connected to the inlets of the first high-pressure fuel pump 200 and the second high-pressure fuel pump 300, respectively. A first pulsation damper 220 is provided in front of the entrance of the first high-pressure fuel pump 200, and a second pulsation damper 320 is provided in front of the entrance of the second high-pressure fuel pump 300, respectively. The fuel pulsation is reduced.

  The discharge port of the first high-pressure fuel pump 200 is connected to the first high-pressure delivery communication pipe 500, and the first high-pressure delivery communication pipe 500 is connected to the high-pressure delivery pipe 112 of one bank of the V-shaped bank. . The discharge port of the second high-pressure fuel pump 300 is connected to the second high-pressure delivery communication pipe 510, and the second high-pressure delivery communication pipe 510 is connected to the high-pressure delivery pipe 112 of the other bank of the V-shaped bank. The The high-pressure delivery pipe 112 of one bank of the V-type bank and the high-pressure delivery pipe 112 of the other bank are connected by a high-pressure communication pipe 520.

  The electromagnetic relief valve 114 provided in the high pressure delivery pipe 112 is connected to the high pressure fuel pump return pipe 600 via the high pressure delivery return pipe 610. Return ports of the high-pressure fuel pump 200 and the high-pressure fuel pump 300 are connected to a high-pressure fuel pump return pipe 600. The high-pressure fuel pump return pipe 600 is connected to the return pipe 620 and the return pipe 630, and is connected to the fuel tank.

  FIG. 2 shows an enlarged view of the vicinity of the first high-pressure fuel pump 200 of FIG. The same applies to the second high-pressure fuel pump 300, but the cam phase is different and the discharge timing phase is shifted to suppress the occurrence of pulsation. The characteristics of the first high-pressure fuel pump 200 and the second high-pressure fuel pump 300 may be the same or different.

  The high-pressure fuel pump 200 includes a pump plunger 206 that is driven by a cam 210 and slides up and down, an electromagnetic spill valve 202, and a check valve 204 with a leak function as main components.

  When the pump plunger 206 is moved downward by the cam 210 and the electromagnetic spill valve 202 is open, fuel is introduced (sucked), and the pump plunger 206 is moved upward by the cam 210. When the electromagnetic spill valve 202 is closed, the timing for closing the electromagnetic spill valve 202 is changed to control the amount of fuel discharged from the high-pressure fuel pump 200. The earlier the timing for closing the electromagnetic spill valve 202 during the pressurization stroke in which the pump plunger 206 is moving upward, the more fuel is discharged, and the slower the fuel is discharged, the slower. The driving duty of the electromagnetic spill valve 202 when discharging the most is 100%, and the driving duty of the electromagnetic spill valve 202 when discharging the least is 0%. When the drive duty of the electromagnetic spill valve 202 is 0%, the electromagnetic spill valve 202 remains open without closing, and as long as the first cam 210 is rotating (as long as the engine is rotating). ) The pump plunger 206 slides in the vertical direction, but the fuel is not pressurized because the electromagnetic spill valve 202 does not close.

  The pressurized fuel is pushed open to the high pressure delivery pipe 112 via the first high pressure delivery communication pipe 500 by pushing open the check valve 204 with a leak function (set pressure of about 60 kPa). At this time, the fuel pressure is feedback controlled by a fuel pressure sensor provided in the high pressure delivery pipe 112. Further, as described above, the high pressure delivery pipe 112 of one bank of the V type and the high pressure delivery pipe 112 of the other bank are communicated by the high pressure communication pipe 520.

  In the high-pressure fuel supply apparatus according to the present embodiment, when the engine is stopped, the electromagnetic relief valve 114 provided in the high-pressure delivery pipe 112 is opened by an engine ECU (Electronic Control Unit) and the high-pressure delivery pipe 112 and the fuel tank are opened. And the fuel pressure is lowered to avoid fuel leakage from the in-cylinder injector 110. Even if the engine ECU gives an open command signal to the electromagnetic relief valve 114, the valve body of the electromagnetic relief valve 114 is fixed, or the signal line between the electromagnetic relief valve 114 and the engine ECU is disconnected or short-circuited. If so, the electromagnetic relief valve 114 will not open. If the operation is continued without detecting such an abnormality, the high-pressure fuel remains in the high-pressure delivery pipe 112 when the engine is stopped, and the fuel may leak from the in-cylinder injector into the intake pipe. Such a fuel leak causes an increase in unburned HC in the exhaust gas at the next engine start. The amount of HC emission at the start-up may become very large within a time of about 1 second. In addition, since the amount of fuel leakage from the injector cannot be managed, the exhaust gas component at the time of engine start varies. Therefore, the high-pressure fuel supply apparatus according to the present embodiment includes an abnormality determination device that is realized by a program executed by the engine ECU.

  A control structure of a program executed by the engine ECU that controls the high-pressure fuel supply apparatus according to the present embodiment will be described with reference to FIG. This program represents only abnormality determination processing for the electromagnetic relief valve 114.

  In step (hereinafter step is abbreviated as S) 100, engine ECU detects engine coolant temperature THW. In S110, engine ECU determines whether or not detected engine coolant temperature THW is lower than threshold value T (0). If engine coolant temperature THW is lower than threshold value T (0) (YES in S110), the process proceeds to S250. If not (NO in S110), the process proceeds to S120.

  In S120, the engine ECU determines whether or not the engine operating state is an idle operating state. If the engine operating state is an idle operating state (YES in S120), the process proceeds to S130. If not (NO in S130), the process proceeds to S250.

  In S130, the engine ECU detects the nozzle hole temperature TINJ of in-cylinder injector 110. At this time, the nozzle hole temperature TINJ is not directly detected by the sensor, but may be estimated from various state quantities. In S140, the engine ECU determines whether or not the detected injection hole temperature TINJ of the in-cylinder injector is lower than threshold value T (1). If the injection hole temperature TINJ of the in-cylinder injector is lower than threshold value T (1) (YES in S140), the process proceeds to S150. If not (NO in S150), the process proceeds to S230.

  In S150, the engine ECU assigns 0 to DI ratio r, which is the injection ratio of in-cylinder injector 110, and injects fuel only from intake manifold injector 120, so that in-cylinder injector 110 Stop operation (stop fuel injection). In S160, the engine ECU outputs a stop command signal to high-pressure fuel pump 200 and high-pressure fuel pump 300. At this time, a signal having the above-described duty of 0 is output.

  In S170, the engine ECU outputs an open command signal to electromagnetic relief valve 114. In S180, engine ECU determines whether or not a predetermined time has elapsed since the opening command signal was output to electromagnetic relief valve 114. Since it takes a certain amount of time for the fuel in the high pressure delivery pipe 112 to escape, the pressure of the fuel in the high pressure delivery pipe after a predetermined time has elapsed since the opening command signal was output to the electromagnetic relief valve 114. This is to detect this. If a predetermined time has elapsed since the opening command signal was output to electromagnetic relief valve 114 (YES in S180), the process proceeds to S190. If not (NO in S180), the process returns to S180 and waits until a predetermined time elapses after the opening command signal is output to the electromagnetic relief valve 114.

  In S190, the engine ECU detects the fuel pressure Pr that is the pressure of the fuel in the high-pressure delivery pipe 112. At this time, the fuel pressure Pr is detected based on a signal input to the engine ECU from a fuel pressure sensor provided in the high pressure delivery pipe 112. In S200, engine ECU determines whether or not detected fuel pressure Pr is lower than Pr (0) that is a predetermined threshold with respect to fuel pressure Pr. If fuel pressure Pr is lower than threshold value Pr (0) (YES in S20), the process proceeds to S210. If not (NO in S200), the process proceeds to S220.

  In S210, the engine ECU determines that electromagnetic relief valve 114 is normal. In S220, engine ECU determines that electromagnetic relief valve 114 is abnormal. At this time, abnormality processing is executed. In this abnormality process, for example, a diagnosis indicating that the electromagnetic relief valve 114 is abnormal is stored in the memory. After the processes of S210 and S220, this process ends.

  In S230, the engine ECU assigns 1 to DI ratio r, which is the injection ratio of in-cylinder injector 110, and injects fuel only from in-cylinder injector 110. In S240, the engine ECU outputs an operation command signal to high-pressure fuel pump 200 and high-pressure fuel pump 300. At this time, a signal whose duty is not 0 is output. Thereafter, this process ends.

  In S250, the engine ECU substitutes a value calculated using maps shown in FIGS. 4 to 7 described later into DI ratio r, which is the injection ratio of in-cylinder injector 110, for in-cylinder injection. Fuel is injected from the injector 110 and the intake passage injector 120. In S260, engine ECU outputs an operation command signal to high-pressure fuel pump 200 and high-pressure fuel pump 300. At this time, a signal whose duty is not 0 is output. Thereafter, this process ends.

  The operation of the high-pressure fuel supply apparatus according to the present embodiment based on the above-described structure and flowchart will be described.

  When a vehicle equipped with an engine having an in-cylinder injector 110 and an intake manifold injector 120 is running, the electromagnetic relief valve 114 is closed and the high pressure fuel pump 200 and the high pressure fuel pump 300 are connected to the high pressure delivery pipe 112 with a high pressure. The fuel is supplied and the fuel is directly injected from the in-cylinder injector 110 into the combustion chamber. Further, depending on the engine speed and load, fuel is injected only from the in-cylinder injector 110, fuel is injected only from the intake manifold injector 120, or fuel is injected from both of these injectors. (See FIGS. 4 to 7 described later).

  When the vehicle stops and the ignition switch is turned off, an open signal is transmitted to open the electromagnetic relief valve 114. As a result, the electromagnetic relief valve 114 is changed from the closed state to the open state. Since the electromagnetic relief valve 114 communicates the high pressure delivery pipe 112 with the fuel tank, the fuel pressure in the high pressure delivery pipe 112 is greatly reduced. Thereby, the fuel leak from the in-cylinder injector 110 can be avoided, and various problems caused by the fuel leak can be solved. Therefore, in this high-pressure fuel supply device, abnormality determination of the electromagnetic relief valve 114 is executed during the operation of the engine that satisfies a specific condition.

  If engine cooling water temperature THW is lower than threshold value T (0) (NO in S110) and the engine operating state is an idle operating state (YES in S120), the nozzle hole temperature of in-cylinder injector 110 TINJ is detected (S130).

  If injection hole temperature TINJ of in-cylinder injector 110 is lower than threshold value T (1) (YES in S140), fuel injection from in-cylinder injector 110 is stopped (S150), and the high-pressure fuel pump 200 and 300 are also stopped (S160). A command signal is output so that the electromagnetic relief valve 114 is opened (S170), and when a predetermined time has elapsed after the output of this command signal (YES in S180), the fuel pressure that is the pressure of the fuel in the high-pressure delivery pipe 112 Pr is detected (S190).

  If the detected fuel pressure Pr is lowered to be lower than the fuel pressure threshold value Pr (0) (YES in S200), it is determined that the electromagnetic relief valve 114 is normal (S210). However, if detected fuel pressure Pr is maintained at or above fuel pressure threshold value Pr (0) (NO in S200), it is determined that electromagnetic relief valve 114 is abnormal (S220).

  That is, even if an open command signal is output to the electromagnetic relief valve 114, the electromagnetic relief valve 114 is not actually opened, and high-pressure fuel remains in the high-pressure delivery pipe 112. For this reason, the fuel pressure Pr does not become lower than the threshold value Pr (0).

  On the other hand, when the abnormality determination of the electromagnetic relief valve 114 provided in the high-pressure delivery pipe 112 that supplies fuel to the in-cylinder injector 110 is executed, the engine coolant temperature is low (YES in S110), and the engine Is the idle operation state (YES in S120), and the tip temperature of in-cylinder injector 110 is low (YES in S140). That is, the engine is lightly loaded and the engine is lightly loaded, and even if the in-cylinder injector 110 is not used, a good combustion state can be maintained only by the intake passage injector 120 (the engine output is the light load). Larger) and does not cause vehicle driving problems. Furthermore, since the engine coolant temperature THW is low (engine temperature is low), the load is low, and the injection hole temperature TINJ of the in-cylinder injector 110 is low, even if the fuel injection from the in-cylinder injector 110 is stopped, Deposits are unlikely to accumulate in the injection hole, and the injection hole of the in-cylinder injector 110 is not blocked.

  As described above, according to the high-pressure fuel supply apparatus according to the present embodiment, the high-pressure delivery pipe is provided with the electromagnetic relief valve that is opened when the engine is stopped and that brings the fuel tank and the high-pressure delivery pipe into communication. Then, when no deposit is deposited in the injection hole of the in-cylinder injector, and when the load is light enough to maintain a good combustion state with only the intake manifold injector, the fuel injection from the in-cylinder injector Was stopped, fuel was injected only with the injector for injection of the intake passage, and the electromagnetic relief valve was opened. At this time, if the fuel pressure in the high-pressure delivery pipe does not decrease, it can be determined that the electromagnetic relief valve is abnormal. As a result, it is possible to determine the abnormality of the electromagnetic relief valve even during engine operation.

  The electromagnetic relief valve 114 may be linearly controlled by the engine ECU.

<Engine suitable for application of this control apparatus (part 1)>
Hereinafter, an engine (part 1) suitable for application of the control device according to the present embodiment will be described.

  Referring to FIGS. 4 and 5, the injection ratio of in-cylinder injector 110 and intake manifold injector 120 (hereinafter referred to as DI ratio (r)), which is information corresponding to the operating state of engine 10, is referred to as DI ratio (r). Will be described). These maps are stored in the ROM 320 of the engine ECU 300. FIG. 4 is a map for the warm of the engine 10, and FIG. 5 is a map for the cold of the engine 10.

  As shown in FIGS. 4 and 5, these maps are shown in percentages where the engine 10 rotation speed is on the horizontal axis, the load factor is on the vertical axis, and the share ratio of the in-cylinder injector 110 is the DI ratio r. It is shown.

  As shown in FIGS. 4 and 5, the DI ratio r is set for each operation region determined by the rotational speed of the engine 10 and the load factor. “DI ratio r = 100%” means a region where fuel injection is performed only from in-cylinder injector 110, and “DI ratio r = 0%” means from intake manifold injector 120. This means that only the region where fuel injection is performed. “DI ratio r ≠ 0%”, “DI ratio r ≠ 100%” and “0% <DI ratio r <100%” indicate that in-cylinder injector 110 and intake passage injector 120 perform fuel injection. It means that the area is shared. In general, the in-cylinder injector 110 contributes to an increase in output performance, and the intake manifold injector 120 contributes to the uniformity of the air-fuel mixture. By using two types of injectors having different characteristics depending on the rotation speed and load factor of the engine 10, the engine 10 is in a normal operation state (for example, when the catalyst is warmed up at idle when the engine 10 is in an abnormal state other than the normal operation state). In this case, only homogeneous combustion is performed.

  Further, as shown in FIGS. 4 and 5, the DI share ratio r of the in-cylinder injector 110 and the intake manifold injector 120 is defined separately for the warm time map and the cold time map. did. If the temperature of the engine 10 is different, the temperature of the engine 10 is detected by detecting the temperature of the engine 10 using a map set so that the control areas of the in-cylinder injector 110 and the intake manifold injector 120 are different. If it is equal to or higher than a predetermined temperature threshold value, the warm time map shown in FIG. 4 is selected. Otherwise, the cold time map shown in FIG. 5 is selected. Based on the selected maps, the in-cylinder injector 110 and / or the intake manifold injector 120 are controlled based on the rotation speed and load factor of the engine 10.

  The engine speed and load factor of engine 10 set in FIGS. 4 and 5 will be described. NE (1) in FIG. 4 is set to 2500 to 2700 rpm, KL (1) is set to 30 to 50%, and KL (2) is set to 60 to 90%. Further, NE (3) in FIG. 5 is set to 2900-3100 rpm. That is, NE (1) <NE (3). In addition, NE (2) in FIG. 4 and KL (3) and KL (4) in FIG. 5 are also set as appropriate.

  Comparing FIG. 4 and FIG. 5, NE (3) of the map for cold shown in FIG. 5 is higher than NE (1) of the map for warm shown in FIG. This indicates that as the temperature of the engine 10 is lower, the control range of the intake manifold injector 120 is expanded to a higher engine speed range. That is, since the engine 10 is in a cold state, deposits are unlikely to accumulate at the injection port of the in-cylinder injector 110 (even if fuel is not injected from the in-cylinder injector 110). For this reason, it sets so that the area | region which injects a fuel using the intake manifold injector 120 may be expanded, and a homogeneity can be improved.

  Comparing FIG. 4 and FIG. 5, in the region where the engine 10 has a rotational speed of NE (1) or higher in the warm map and in the region of NE (3) or higher in the cold map, “DI ratio r = 100% ". Further, the load factor is “DI ratio r = 100%” in the region of KL (2) or higher in the warm map and in the region of KL (4) or higher in the cold map. This indicates that only the in-cylinder injector 110 is used in a predetermined high engine speed region, and only the in-cylinder injector 110 is used in a predetermined high engine load region. . That is, in the high speed region and the high load region, even if the fuel is injected only by the in-cylinder injector 110, the engine 10 has a high rotational speed and load, and the intake amount is large. It is because it is easy to homogenize. Thus, the fuel injected from the in-cylinder injector 110 is vaporized with latent heat of vaporization (sucking heat from the combustion chamber) in the combustion chamber. Thereby, the temperature of the air-fuel mixture at the compression end is lowered. As a result, the knocking performance is improved. Further, since the temperature of the combustion chamber is lowered, the suction efficiency is improved and high output can be expected.

  In the warm map shown in FIG. 4, only the in-cylinder injector 110 is used at a load factor KL (1) or less. This indicates that when the temperature of the engine 10 is high, only the in-cylinder injector 110 is used in a predetermined low load region. This is because when the engine 10 is warm, the engine 10 is in a warm state, and deposits are likely to accumulate at the injection port of the in-cylinder injector 110. However, since the injection port temperature can be lowered by injecting fuel using the in-cylinder injector 110, it is conceivable to avoid deposit accumulation, and the minimum fuel injection amount of the in-cylinder injector Therefore, it is conceivable that the in-cylinder injector 110 is not blocked, and for this reason, the in-cylinder injector 110 is used as an area.

  Comparing FIG. 4 and FIG. 5, there is an area of “DI ratio r = 0%” only in the cold map of FIG. This indicates that when the temperature of the engine 10 is low, only the intake manifold injector 120 is used in a predetermined low load region (KL (3) or less). This is because the engine 10 is cold and the load on the engine 10 is low and the intake air amount is low, so that the fuel is difficult to atomize. In such a region, it is difficult to perform good combustion with the fuel injection by the in-cylinder injector 110. In particular, a high output using the in-cylinder injector 110 is required in the region of low load and low rotation speed. Therefore, only the intake passage injector 120 is used without using the in-cylinder injector 110.

  In addition, in the case other than the normal operation, the in-cylinder injector 110 is controlled so as to perform stratified combustion when the engine 10 is at the time of catalyst warm-up when idling (in a non-normal operation state). By performing stratified charge combustion only during such catalyst warm-up operation, catalyst warm-up is promoted and exhaust emission is improved.

<Engine suitable for application of this control device (part 2)>
Hereinafter, an engine (part 2) suitable for application of the control device according to the present embodiment will be described. In the following description of the engine (part 2), the same description as the engine (part 1) will not be repeated here.

  With reference to FIGS. 6 and 7, a map representing the injection ratio of in-cylinder injector 110 and intake manifold injector 120 that is information corresponding to the operating state of engine 10 will be described. These maps are stored in the ROM 320 of the engine ECU 300. FIG. 6 is a warm map of the engine 10, and FIG. 7 is a cold map of the engine 10.

  6 and 7 differ from FIGS. 4 and 5 in the following points. The rotational speed of the engine 10 is “DI ratio r = 100%” in the region of NE (1) or more in the warm map and in the region of NE (3) or more in the cold map. In the region where the load factor is KL (2) or higher excluding the low rotational speed region in the warm map, and in the region where KL (4) is higher than the low rotational speed region in the cold map, “DI” Ratio r = 100% ”. This is because only the in-cylinder injector 110 is used in a predetermined high engine speed region, and only the in-cylinder injector 110 is used in a predetermined high engine load region. Indicates. However, in the high load region of the low engine speed region, mixing of the air-fuel mixture formed by the fuel injected from the in-cylinder injector 110 is not good, and the air-fuel mixture in the combustion chamber is inhomogeneous and combustion is unstable. Tend to be. For this reason, the injection ratio of the in-cylinder injector is increased with the shift to the high rotation speed region where such a problem does not occur. In addition, the injection ratio of the in-cylinder injector 110 is decreased as the engine shifts to a high load region where such a problem occurs. These changes in the DI ratio r are indicated by cross arrows in FIGS. If it does in this way, the fluctuation | variation of the output torque of an engine resulting from combustion being unstable can be suppressed. It should be noted that these things can be achieved by reducing the injection ratio of the in-cylinder injector 110 as the engine shifts to the predetermined low rotational speed region, or by the in-cylinder injection as the vehicle shifts to the predetermined low load region. The fact that it is substantially equivalent to increasing the injection ratio of the injector 110 for operation will be described. Further, areas other than such areas (areas where cross arrows are shown in FIGS. 6 and 7) and areas where fuel is injected only by the in-cylinder injector 110 (high rotation side, low load) On the other hand, it is easy to homogenize the air-fuel mixture with the in-cylinder injector 110 alone. Thus, the fuel injected from the in-cylinder injector 110 is vaporized with latent heat of vaporization (sucking heat from the combustion chamber) in the combustion chamber. Thereby, the temperature of the air-fuel mixture at the compression end is lowered. As a result, the knocking performance is improved. Further, since the temperature of the combustion chamber is lowered, the suction efficiency is improved and high output can be expected.

  In the engine 10 described with reference to FIGS. 4 to 7, the homogeneous combustion is performed by setting the fuel injection timing of the in-cylinder injector 110 as the intake stroke, and the stratified combustion is performed by the fuel of the in-cylinder injector 110. This can be realized by setting the injection timing to the compression stroke. That is, by setting the fuel injection timing of the in-cylinder injector 110 as the compression stroke, stratified combustion is realized in which the rich air-fuel mixture is unevenly distributed around the spark plug and the entire combustion chamber ignites a lean air-fuel mixture. Can do. Further, even when the fuel injection timing of the in-cylinder injector 110 is set to the intake stroke, if rich air-fuel mixture can be unevenly distributed around the spark plug, stratified combustion can be realized even with the intake stroke injection.

  Further, the stratified combustion here includes both stratified combustion and weakly stratified combustion described below. In the weak stratified combustion, the intake passage injector 120 is injected with fuel in the intake stroke to produce a lean and homogeneous mixture in the entire combustion chamber, and the in-cylinder injector 110 is injected with fuel in the compression stroke. A rich air-fuel mixture is generated around the spark plug to improve the combustion state. Such weak stratified combustion is preferable when the catalyst is warmed up. This is due to the following reason. That is, it is necessary to significantly retard the ignition timing and maintain a good combustion state (idle state) in order to allow high-temperature combustion gas to reach the catalyst during catalyst warm-up. Moreover, it is necessary to supply a certain amount of fuel. Even if this is done by stratified combustion, there is a problem that the amount of fuel is small, and even if this is done by homogeneous combustion, there is a problem that the retard amount is small compared to stratified combustion to maintain good combustion. is there. From such a viewpoint, it is preferable to use the above-described weak stratified combustion at the time of warming up the catalyst, but either stratified combustion or weak stratified combustion may be used.

  In the engine described with reference to FIGS. 4 to 7, the fuel injection timing by the in-cylinder injector 110 is preferably performed in the compression stroke for the following reason. However, in the engine 10 described above, in a basic most region (a weak operation that is performed only when the catalyst is warmed up, the intake passage injection injector 120 is injected in the intake stroke and the in-cylinder injector 110 is compressed in the compression stroke. The timing of fuel injection by the in-cylinder injector 110 other than the stratified combustion region is a basic region) is the intake stroke. However, for the following reasons, the fuel injection timing of the in-cylinder injector 110 may be temporarily set to the compression stroke injection for the purpose of stabilizing the combustion.

  By setting the fuel injection timing from the in-cylinder injector 110 during the compression stroke, the air-fuel mixture is cooled by fuel injection at a time when the in-cylinder temperature is higher. Since the cooling effect is enhanced, knock resistance can be improved. Furthermore, if the fuel injection timing from the in-cylinder injector 110 is in the compression stroke, the time from the fuel injection to the ignition timing is short, so that the air flow can be strengthened by spraying and the combustion speed can be increased. From these improvement in knocking property and increase in combustion speed, combustion fluctuation can be avoided and combustion stability can be improved.

  Furthermore, regardless of the temperature of the engine 10 (that is, whether the engine is warm or cold), it is off-idle (when the idle switch is off or the accelerator pedal is depressed). 4 or 6 may be used (the in-cylinder injector 110 is used in the low load region regardless of the cold temperature).

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall schematic diagram of a fuel supply system for a gasoline engine controlled by a control device according to an embodiment of the present invention. It is the elements on larger scale of FIG. It is a flowchart which shows the control structure of the program performed in the control apparatus which concerns on embodiment of this invention. FIG. 5 is a diagram (No. 1) showing a DI ratio map when the engine is suitable for application of the control device according to the embodiment of the present invention. It is FIG. (1) showing the DI ratio map at the time of cold of an engine suitable for the control apparatus which concerns on embodiment of this invention to be applied. FIG. 6 is a diagram (No. 2) showing a DI ratio map when the engine is suitable for application of the control device according to the embodiment of the present invention. FIG. 7 is a diagram (No. 2) showing a DI ratio map during cold engine suitable for application of the control device according to the embodiment of the present invention;

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel supply system, 100 Feed pump, 110 In-cylinder injector, 112 High pressure delivery pipe, 114 Electromagnetic relief valve, 120 Intake passage injection injector, 122 Low pressure delivery pipe, 200 1st high pressure fuel pump, 202 Electromagnetic spill valve 204, check valve with leak function, 206 pump plunger, 210 first cam, 220 first pulsation damper, 300 second high pressure fuel pump, 310 second cam, 320 second pulsation damper, 400 Low pressure supply pipe, 410 First low pressure delivery communication pipe, 420 Pump supply pipe, 430 Second low pressure delivery communication pipe, 500 First high pressure delivery communication pipe, 510 Second high pressure delivery communication pipe, 520 High pressure communication Pipe, 600 high pressure fuel pump return pipe, 610 high pressure delivery return pipe, 620, 630 return pipe.

Claims (6)

An abnormality determination device for a high-pressure fuel supply apparatus for an internal combustion engine, comprising: a first fuel injection means for injecting fuel into a cylinder; and a second fuel injection means for injecting fuel into an intake passage. , Based on conditions required for the internal combustion engine, the first fuel injection unit and the second fuel injection unit are controlled to inject fuel and the high pressure fuel supply device is A delivery pipe for supplying fuel supplied from a fuel tank to the first fuel injection means; and a relief valve for switching the delivery pipe and the fuel tank between a communication state and a non-communication state. ,
Control means for controlling the relief valve;
Determining means for determining an abnormality of the relief valve,
The determination means includes
When a predetermined condition is satisfied for the internal combustion engine, the first fuel injection means is deactivated, and the relief valve is controlled so as to enter the communication state, and then the fuel pressure of the delivery pipe is reduced. Means for detection;
An abnormality determination device for a high-pressure fuel supply apparatus for an internal combustion engine, comprising: means for determining abnormality of the relief valve based on the detected fuel pressure.   The abnormality determination of the high-pressure fuel supply device for an internal combustion engine according to claim 1, wherein the predetermined condition for the internal combustion engine is a condition that a temperature of the first fuel injection means is equal to or lower than a predetermined temperature. apparatus.   3. The abnormality determination device for a high-pressure fuel supply apparatus for an internal combustion engine according to claim 1, wherein the predetermined condition for the internal combustion engine is a condition that an operation state of the internal combustion engine is an idle operation state.   The said determination means includes a means for determining that the relief valve is abnormal when the detected fuel pressure is equal to or higher than a predetermined pressure. An abnormality determination device for a high-pressure fuel supply device of an internal combustion engine.   The control means includes means for controlling the relief valve so as to be in the non-communication state during operation of the internal combustion engine and to be in the communication state when the internal combustion engine is stopped. The abnormality determination device for a high-pressure fuel supply device for an internal combustion engine according to any one of claims 1 to 4. The first fuel injection means is an in-cylinder injector,
The abnormality determination device for a high-pressure fuel supply apparatus for an internal combustion engine according to any one of claims 1 to 5, wherein the second fuel injection means is an intake passage injection injector.

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