JP2010084660A - Control method for direct-injection engine with turbosupercharger, and control device for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain excellent starting performance by increasing an output by supercharging immediately after starting an engine when restarting the engine according to a request for starting a vehicle after an automatic stop, in a direct-injection engine DE with a turbosupercharger mounted to the vehicle performing an idle stop. <P>SOLUTION: If there is the request for starting the vehicle when the engine DE is restarted after the automatic stop, additional fuel injection is performed in the expansion stroke of a predetermined cylinder 14 before the completion of starting, and an exhaust heat quantity is effectively increased by taking advantage of the start of the rotation of the engine. Thereby, supercharging is promptly started. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device that automatically stops an engine when a predetermined condition is satisfied, and then restarts the engine, and particularly relates to restart control suitable for a direct injection engine with a turbocharger.

  Conventionally, for the purpose of reducing fuel consumption, suppressing CO2 emission, and the like, for example, it is known to automatically stop an engine if a predetermined condition is satisfied during a temporary stop of a vehicle (a so-called idle stop, an example) In particular, when restarting the engine in response to a vehicle start request, it is required to increase the output immediately after starting with a more reliable restart.

In this regard, in the case of an engine equipped with a turbocharger, the compression ratio of the cylinder is generally low and the startability tends to be inferior, especially in a diesel engine that self-ignites the fuel by compression of the cylinder. This problem becomes noticeable. Therefore, for example, in the diesel engine described in Patent Document 2, the turbocharger is driven by an electric motor at the time of start, so that the boost pressure is quickly increased to improve the startability.
JP 2000-274273 A JP 2007-2111710 A

  However, the technology disclosed in Patent Document 2 cannot be realized unless it is a turbocharger that can be assisted by an electric motor, and such a turbocharger has not been put into practical use.

  In addition, as disclosed in the same document, there is a problem that the battery voltage decreases with the driving of the electric motor for assisting supercharging, and sufficient power cannot be supplied to the starter motor.

  SUMMARY OF THE INVENTION The present invention has been made in view of such a point, and an object of the present invention is to start supercharging as quickly as possible without starting motor assist or the like when restarting the engine for starting the vehicle. Immediately after that, the output is increased by supercharging so that a good start performance can be obtained.

  In order to achieve the above object, according to the present invention, if there is a vehicle start request when the engine is restarted, the fuel injection amount to a predetermined cylinder is increased before the start is completed, and the exhaust heat amount is increased by taking advantage of the rise of the engine rotation. By increasing effectively, supercharging was started immediately.

  Specifically, the invention of claim 1 is directed to an engine control method for stopping an engine in response to establishment of a predetermined automatic stop condition, and then restarting the engine if a predetermined restart condition is satisfied. is there.

  When the engine includes a fuel injection valve that directly injects fuel into the combustion chamber in the cylinder, and a turbocharger that is driven by an exhaust flow to supercharge intake air, the restart condition is satisfied. At the time of establishment, it is determined whether there is a vehicle start request based on the operation of the occupant, and when it is determined that there is a start request, when the engine speed rises at the time of restart compared to when it is determined that there is no start request The fuel injection amount to the predetermined cylinder is increased so that the amount of fuel consumed is increased.

  By the above method, when the engine is restarted in response to a vehicle start request, the engine speed is accelerated by the combustion of the cylinder, and a predetermined amount of fuel is consumed so that the amount of fuel consumed when the speed rises increases. The amount of fuel injected into the cylinder is increased. In other words, immediately after the engine starts to start, the rotation is too slow, so even if the fuel is increased, the amount of heat generated per hour does not increase so much and the heat loss is large. The amount of heat cannot be increased. In addition, there is a possibility that the fluctuation of the engine speed increases as the amount of fuel increases, resulting in deterioration of vibration and noise.

  Therefore, for example, after the combustion starts in one of the cylinders at the time of restart, after the compression top dead center of the first (or the second) cylinder is exceeded, the fuel increase is started from the cylinder in the compression stroke. (Claim 5) When the rotation of the engine is accelerated by the combustion of the cylinder twice (or three times) and the rotation speed rapidly increases (rises), the amount of fuel consumed is increased. Can do. Note that the fuel may be increased when the engine speed (instantaneous speed) becomes equal to or higher than the set speed during restart.

  If the amount of fuel is increased by taking advantage of the rise of the engine speed, the amount of exhaust heat is effectively increased even when the engine is restarted, and supercharging by the turbocharger is started immediately. become. As a result, the output can be improved by supercharging immediately after the engine is started, and a good start performance can be obtained.

  In particular, a compression self-ignition type engine such as a diesel engine (Claim 3) has a possibility that the ignitability and the combustibility may be lowered when the intake air is low. The benefits are high. Moreover, since the excess air ratio (λ) is usually in a lean state that is considerably larger than 1 in a diesel engine, the amount of fuel increase is relatively large, and it is possible to increase the amount of exhaust heat by sufficient fuel increase. .

  The determination as to whether or not there is a vehicle start request can be made based on at least one operation of the occupant's brake, accelerator, clutch, and shift lever (Claim 2). It is possible to accurately determine the vehicle start request. Further, when increasing the amount of fuel as described above, it is preferable to inject the increased amount of fuel during the expansion stroke of the cylinder (claim 4), and this makes it possible to increase the amount of exhaust heat more effectively.

  From another viewpoint, the present invention is an engine control device that stops the engine in response to establishment of a predetermined automatic stop condition, and then restarts the engine if a predetermined restart condition is satisfied, The engine is a case of a multi-cylinder diesel engine that includes a fuel injection valve that directly injects fuel into a combustion chamber in a cylinder, and a turbocharger that is driven by an exhaust flow to supercharge intake air.

  And a start request determining means for determining whether or not there is a start request of the vehicle based on at least one operation of the brake, accelerator, clutch and shift lever of the occupant when the restart condition is satisfied; When it is determined that there is a request, the fuel injection amount to the predetermined cylinder is set so that the amount of fuel consumed when the engine speed rises at the time of restart is larger than when it is determined that there is no start request. And a fuel increasing means for increasing the fuel amount (claim 6).

  According to the control device having such a configuration, the control method according to the first to third aspects of the invention described above can be easily executed, and the operation of the invention can be easily and reliably obtained.

  As described above, according to the control method and the like of the turbocharger-equipped direct injection engine according to the present invention, the engine is automatically stopped when a predetermined condition is satisfied, and then restarted. If there is a vehicle start request at the time of the restart, the amount of exhaust heat can be effectively increased by taking advantage of the rise of the engine rotation by increasing the fuel injection amount to the predetermined cylinder before the start is completed. As a result, the supercharging starts immediately and the supercharging effect is obtained immediately after the engine is started, and a good start performance can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

(Schematic configuration of the engine)
FIG. 1 shows a schematic configuration of an engine DE according to an embodiment of the present invention. In the example shown in the figure, the engine DE is an in-line four-cylinder diesel engine, and the cylinder head 11 and the cylinder block 12 are formed with four cylinders 14, 14,. Although only one cylinder 14 is shown in the figure, when distinguishing four cylinders, they are designated as 14A, 14B, 14C, 14D in order from the first cylinder on the engine front side.

  In each cylinder 14, a piston 16 connected to a crankshaft 15 by a connecting rod (not shown) is fitted and moved up and down as the crankshaft 15 rotates. In the cylinder engine, each of the cylinders 14A to 14D performs a combustion cycle including intake, compression, expansion, and exhaust strokes with a phase difference of 180 ° in crank angle. For example, the combustion cycle is performed in the order of the first cylinder 14A, the third cylinder 14C, the fourth cylinder 14D, and the second cylinder 14B.

  A cavity 16 a that defines a combustion chamber 17 is formed on the upper surface of the piston 16, and a glow plug 18 is disposed in the cylinder head 11 with the tip facing the combustion chamber 17. The cylinder head 11 is provided with a fuel injection valve 19 for each cylinder 14. The fuel injection valve 19 is connected to a common rail 20 that stores fuel in a high-pressure state via a branch pipe 21 for each cylinder 14, and high-pressure fuel supplied from the common rail 20 is directly fed into each cylinder 14. , Is supposed to spray.

  In this embodiment, a fuel pressure sensor SW1 for detecting the fuel pressure is provided in the common rail 20, and the fuel injection amount of the fuel injection valve 19 is controlled by the energization time. A common rail 20 that supplies fuel to the fuel injection valve 19 is connected to a fuel supply pump 23 via a high-pressure fuel supply pipe 22.

  In addition, the cylinder head 11 is provided with an intake port 24 and an exhaust port 25 that open toward the combustion chamber 17 for each cylinder 14, and these ports 24, 25 have openings at the openings to the combustion chamber 17. An intake valve 26 and an exhaust valve 27 are provided. The valve operating systems that drive the intake and exhaust valves 26 and 27 are each provided with known phase variable mechanisms 26A and 27A that can change the rotational phase of the camshaft relative to the crankshaft 15 within a predetermined angle range. .

  An intake passage 28 and an exhaust passage 30 are connected to the intake port 24 and the exhaust port 25, respectively. The downstream portion of the intake passage 28 is a branched intake passage 28a branched for each cylinder 14, and the upstream end of each branched intake passage 28a communicates with the surge tank 28b. An upstream side of the surge tank 28b is a common intake passage 28c, in which an electromagnetic throttle valve 29 for restricting the flow of intake air is provided.

  An intercooler 28d that cools high-temperature and high-pressure intake air compressed by a turbocharger 31 described later is provided in the common intake passage 28c upstream of the throttle valve 29. Further, as schematically shown in the figure, the common intake passage 28c is provided with an air flow sensor SW2 for detecting the intake flow rate, an intake pressure sensor SW3 for detecting the intake pressure, and an intake temperature sensor SW4 for detecting the intake temperature. It has been.

  On the other hand, the upstream portion of the exhaust passage 30 is also a branched exhaust passage branched for each cylinder 14, and the intake manifold is superposed on the downstream side of the exhaust manifold where the branched exhaust passages are assembled by being driven by the exhaust flow. A turbocharger 31 is disposed. This is composed of a turbine 31a that rotates in response to an exhaust flow, and a blower 31b that is rotatably connected to the turbine 31a and pumps intake air into the intake passage 28 upstream of the intercooler 28d. Although illustration is omitted, a catalyst, a particulate filter (DPF) and the like for purifying exhaust gas are disposed in the common exhaust passage downstream of the turbine 31a of the turbocharger 31.

  Further, an alternator 32 connected to the crankshaft 15 by a timing belt or the like is attached to the engine DE. This alternator 32 has a built-in regulator circuit 33 that adjusts the amount of power generated by controlling the current of a field coil (not shown) and adjusting the output voltage, depending on the electric load of the vehicle, the remaining capacity of the in-vehicle battery, and the like. Appropriate power generation operation.

  Further, the engine DE is provided with a starter motor 34 for starting it. The starter motor 34 has a motor body 34a and a pinion gear 34b. The pinion gear 34b reciprocates on the output shaft of the motor body 34a in a state where relative rotation is impossible. The crankshaft 15 is provided with a concentric ring gear 35 fixed to a flywheel (not shown). When the engine DE is restarted using the starter motor 34, the pinion gear 34b. Is moved to a predetermined meshing position and meshed with the ring gear 35, whereby the crankshaft 15 is rotationally driven.

  Further, the engine DE is provided with two crank angle sensors SW5 and SW6 for detecting the rotation angle of the crankshaft 15, and the engine speed is determined based on a detection signal (pulse signal) output from one crank angle sensor SW5. Is detected, and the crank angle position is detected based on the detection signals out of phase output from the crank angle sensors SW5 and SW6.

  Further, as shown in the figure, a water temperature sensor SW7 for detecting the coolant temperature of the engine DE, an accelerator opening sensor SW8 for detecting an accelerator opening corresponding to the operation amount of the accelerator pedal 36 of the vehicle, and a brake pedal 37 of the vehicle. The brake pedal sensor SW9 for detecting the operation, the clutch pedal sensor SW10 for detecting the operation of the clutch pedal 38 of the vehicle, the shift lever sensor SW11 for detecting the operation of the shift lever 39 of the vehicle, and the traveling speed (vehicle speed) of the vehicle. A vehicle speed sensor SW12 for detection is provided.

  In addition, the illustrated engine DE is provided with an exhaust gas recirculation device 40, which is branched and connected in the vicinity of the exhaust manifold assembly portion to circulate a part of the exhaust gas from the exhaust passage 30 to the intake passage 28. An EGR (Exhaust Gas Recirculation) passage 41 and an EGR valve 42 provided in the middle of the EGR passage 41 to restrict the flow of exhaust gas to be recirculated.

  The engine DE described above is controlled by a powertrain control module 100 (hereinafter, PCM) schematically shown in FIG. The PCM 100 includes a microprocessor having a CPU, a memory, a counter timer group, an interface, and a path connecting these units. The PCM 100 performs various operations based on signals from the sensors SW1 to SW12 to perform engine DE and The state of the vehicle is determined, and in response to this, a control signal is output to the fuel injection valve 19, the phase variable mechanisms 26A and 27A of the valve system, the throttle valve 29, the actuator of the EGR valve 42, and the like.

  Further, when the engine DE is started, the PCM 100 outputs a control signal to the fuel injection valve 19 and the starter motor 34 and also outputs a control signal to the glow plug 18 as necessary. That is, when the engine DE is cold-started, the glow plug 18 is energized to warm the inside of the cylinder 14 to assist the self-ignition of fuel (air mixture) together with the compression of the cylinder 14.

(Control procedure at restart)
In this embodiment, for the purpose of reducing fuel consumption and CO2 emission, the engine DE is automatically stopped when a predetermined automatic stop condition is satisfied, and then the engine DE is stopped if a predetermined restart condition is satisfied. It is made to restart (so-called idle stop). That is, when the PCM 100 determines that the automatic stop condition of the engine DE is satisfied, the PCM 100 stops the fuel injection by the fuel injection valve 19 (fuel cut) and stops the engine DE.

  Thereafter, if a predetermined restart condition is satisfied, the PCM 100 starts cranking of the engine DE by the starter motor 34 and starts supplying fuel to each of the cylinders 14A to 14D to restart the engine DE. In such a restart after an automatic stop, a more reliable start is required compared to a normal start corresponding to the occupant's ignition operation. When restarting for starting the vehicle, the output is immediately increased after the start. It is also required.

  However, in general, an engine with a turbocharger has a characteristic supercharging delay (turbo lag), and it is difficult to increase the engine output immediately after starting. In particular, in a diesel engine that performs diffusion combustion, if the fuel is greatly increased in a state where air is insufficient due to a delay in supercharging, there is a risk that the smoke will increase rapidly, so that it is not possible to increase the engine output significantly to increase the engine output. There is a real situation.

  On the other hand, in this embodiment, as a characteristic part of the present invention, if there is a vehicle start request at the time of restart after automatic stop, the fuel consumed is increased by multiplying the rise of the engine rotation before the start is completed. By increasing the amount of fuel injected into the predetermined cylinder 14 at the same time, the amount of exhaust heat is effectively increased, and supercharging is started immediately after starting.

  Hereinafter, the restart control of the engine DE after the automatic stop in the vehicle of this embodiment will be specifically described with reference to FIGS. FIG. 2 is a flowchart showing an example of a specific control procedure, and FIG. 3 is a timing chart showing changes in the engine speed when the engine is started.

-Specific control procedure-
First, in the restart control of the engine DE shown in FIG. 2, the process waits until a predetermined restart condition is satisfied in steps S1 and S2 after the start. That is, in step S1, for example, the remaining capacity of the on-vehicle battery is reduced and charging is required, the compressor of the air conditioner is required to operate, or the brake negative pressure is required. It is determined that the restart condition is satisfied. If YES, the process proceeds to step S3. If NO, the process proceeds to step S2.

  In this step S2, if the occupant depresses the accelerator pedal 36 or the clutch pedal 38, or the shift lever 39 is operated, the engine DE needs to be started to start the vehicle. While it is determined that the condition is satisfied, YES is determined, otherwise, NO is determined and the process returns. In this way, it is possible to accurately determine the vehicle start request at a relatively early stage based on the operation of the passenger's accelerator or clutch.

  Then, the starter motor 34 is driven in step S3, where the restart condition according to the system requirements is established (YES in step S1), and the engine DE starts rotating at time t1 in FIG. The air in the cylinder 14 that has been stopped in the compression stroke (the first cylinder 14A in the example of FIG. 3 and hereinafter also referred to as the compression stroke cylinder 14A at the time of stop) is compressed and its temperature rises. When fuel is injected in the vicinity of the compression top dead center (TDC) into the high-temperature cylinder 14A (step S4: see also FIG. 3B), this fuel spray is instantly vaporized to ignite and burn. To do.

  Then, after the combustion of the first cylinder 14A is performed, similarly, the cylinder 14C stopped in the intake stroke (also referred to as a stop intake stroke cylinder, hereinafter the same), the stop exhaust stroke cylinder 14D,. Combustion is performed in sequence (step S5), and as shown by a solid line in FIG. 3A, the rotation of the engine DE rises from about time t2, and the engine speed reaches a predetermined start in step S6 of the flow of FIG. If it is determined that the engine speed is equal to or higher than YES (complete explosion), the routine proceeds to a normal control routine for the engine DE and the start control is terminated (end).

  As described above, the injection of fuel from the stop-time compression stroke cylinder 14A is started only when the piston 16 of the cylinder 14A is stopped in an appropriate stop range suitable for restart. Is outside the proper stop range, fuel injection is started from the stop-time intake stroke cylinder 14C that reaches the compression stroke following the cylinder 14A.

  On the other hand, in step S7, where it is determined that the restart condition for starting the vehicle is satisfied in step S2 (YES in step S2), the starter motor 34 is driven in the same manner as in step S3, and the engine DE is turned on. While starting to rotate (time t1 in FIG. 3 (a)), fuel is injected in the compression stroke cylinder 14A at the stop in the vicinity of TDC (step S8: see also FIG. 3 (b)) to ignite and burn.

  In step S9, it is determined that the intake stroke 14C at the time of stoppage shifts to the compression stroke (TDC passing?), Fuel is also injected into the cylinder 14C in the vicinity of the TDC (step S10), and the cylinder 14C is further expanded. (Step S11: TDC passing?), Additional injection for fuel increase is performed as described below (Steps S12 to S16: indicated by a one-dot chain line in FIG. 3B).

  That is, in step S12, it is determined whether or not the establishment of the restart condition in step S2 is based only on depression of the clutch pedal 38 (clutch ON?). If YES, the process proceeds to step S13 and the injection amount Q1 is added. On the other hand, if NO, the process proceeds to step S14, where it is determined whether or not it is based on depression of the clutch pedal 38 and operation of the shift lever (clutch ON and gear IN?). If this determination is YES, the process proceeds to step S15 to perform additional injection of the injection amount Q2 (> Q1), while if NO, the process is restarted based on depression of the accelerator pedal 36, so the process proceeds to step S16 and the injection amount An additional injection of Q3 (> Q2) is performed.

  By performing the additional injection in this manner, as shown by a one-dot chain line in FIG. 3A, the start of the engine rotation from about time t2 becomes steep, and the start-up is completed quickly. That is, the fuel is increased (additional injection) sequentially even in the cylinder 14 that reaches the combustion timing until it is determined in step S6 that complete explosion has occurred, while if it is determined in step S6 that complete explosion has occurred, normal control of the engine DE is performed. The routine proceeds to a routine and the start control is terminated.

  In other words, when the engine DE after the automatic stop is restarted in response to a vehicle start request, for example, after the first TDC is exceeded after the combustion starts in the compression stroke cylinder 14A at the time of stop, the engine DE is in the compression stroke. By starting additional injection from the intake stroke cylinder 14C at the time of stop and increasing the amount of fuel, the amount of fuel consumed when the engine speed suddenly increases (starts up) after time t2 in FIG. 3 is increased. As a result, the amount of exhaust heat can be effectively increased, and supercharging is started immediately after the engine DE is started.

  The flow of FIG. 2 corresponds to the engine DE idle stop control procedure in which the engine DE is automatically stopped and then restarted if a predetermined restart condition is satisfied. This represents a control procedure for determining whether or not there is a vehicle start request based on an occupant's operation (operation of at least one of a brake, an accelerator, a clutch, and a shift lever) when the restart condition is satisfied.

  Further, in steps S12, S14, and S15, when it is determined that there is a vehicle start request when restarting the engine DE, the amount of fuel consumed when the engine speed rises is larger than when there is no start request. In this way, a control procedure for increasing the fuel injection amount to the predetermined cylinder 14 is shown.

  In this embodiment, when the engine DE is restarted, after the first compression top dead center (TDC) is exceeded after the combustion starts in any one of the cylinders 14, the increase in fuel from the cylinders 14 in the compression stroke is increased. The increased amount of fuel is additionally injected during the expansion stroke of the cylinder 14. By performing additional injection in the expansion stroke in this way, the amount of exhaust heat can be increased more effectively.

  Then, a start request determination means for determining whether or not there is a start request of the vehicle based on the accelerator or clutch operation of the occupant when the restart condition of the engine DE is satisfied by the PCM 100 that executes the control procedure as described above, Fuel increasing means for increasing the amount of fuel injected into the predetermined cylinder 14 is configured so that the amount of fuel consumed when the engine rotation rises is determined when it is determined that there is a start request.

  Therefore, according to the control method or the like of the turbocharger-equipped direct injection engine according to this embodiment, when the engine DE is automatically stopped in a predetermined situation and then restarted in response to a start request by a vehicle occupant, By increasing the fuel injection amount to the predetermined cylinder 14 immediately before the completion of the start, it is possible to effectively increase the amount of exhaust heat by taking advantage of the rise of the engine rotation as described above. Immediately after that, the turbocharger 31 performs supercharging of intake air to obtain a good start performance.

  That is, immediately after the engine DE starts rotating at the time of restart, the rotation is too slow, so even if the amount of fuel is increased, the amount of heat generated per hour does not increase so much and the heat loss is also large. The amount of heat cannot be increased. Moreover, there is a possibility that the rotational fluctuation of the engine DE increases with the fuel increase, and the vibration and noise deteriorate.

  On the other hand, as in this embodiment, the fuel increase (additional injection) is started from the stop-time intake stroke cylinder 14C that reaches the compression stroke beyond the first TDC after the first combustion at the start is performed. By doing so, as shown by the one-dot chain line in FIG. 3 (a), the amount of fuel consumed when the engine speed rises increases, that is, the fuel is increased by multiplying the rise of the engine speed, The amount of exhaust heat can be effectively increased.

  In particular, the compression self-ignition type diesel engine DE has a possibility that the ignitability and the combustibility may be lowered in a state where the intake air is small, and there is a great merit that the supercharging starts quickly as described above. Moreover, since the diesel engine DE is usually operated in a lean state where the excess air ratio (λ) is considerably larger than 1, the fuel increase amount is relatively large, and the exhaust heat quantity can be sufficiently increased. .

  In the above-described embodiment, the start request is determined based on the occupant's accelerator, clutch, and shift lever operations. However, other than that, for example, the brake operation, for example, based on the release of the brake pedal 37, for example. It is also possible to determine a start request.

  In the above-described embodiment, the timing at which the fuel increase is started is determined based on the number of times that the TDC of the cylinder 14 has been exceeded when the engine DE is restarted. However, the present invention is not limited to this. The fuel increase may be started when) becomes equal to or higher than the set rotational speed.

  In the above embodiment, the increased amount of fuel is additionally injected during the expansion stroke of the cylinder 14, but the amount of main injection fuel that starts near the compression top dead center may be increased.

  Further, the present invention is not limited to an engine that self-ignites the fuel by compression of the cylinder 14 such as a diesel engine DE, but is applicable to various engines using a direct injection gasoline engine, a natural gas engine, a hydrogen engine, and other alternative fuels. Applicable.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a passenger car or the like because an engine with a turbocharger mounted on a vehicle that performs an idle stop can reduce a supercharging delay after restarting and obtain a good start performance.

1 is a schematic configuration diagram of an engine mounted on a vehicle according to the present invention. It is a flowchart figure which shows the procedure of the engine control at the time of restart. FIG. 5 is a timing chart showing the fuel increase for each cylinder and the rise of engine rotation in association with each other when the engine is restarted.

Explanation of symbols

DE diesel engine (engine)
14 cylinder 17 combustion chamber 19 fuel injection valve 31 turbocharger 100 PCM (start request determination means, fuel increase means)

Claims (6)

An engine control method for stopping an engine in response to establishment of a predetermined automatic stop condition, and then restarting the engine if a predetermined restart condition is satisfied,
The engine includes a fuel injection valve that directly injects fuel into a combustion chamber in a cylinder, and a turbocharger that is driven by an exhaust flow to supercharge intake air.
When the restart condition is satisfied, it is determined whether there is a vehicle start request based on the operation of the occupant,
When it is determined that there is a vehicle start request, fuel injection to a predetermined cylinder is performed so that the amount of fuel consumed when the engine speed rises at the time of restart is greater than when it is determined that there is no start request. Increase the amount,
A control method for a direct injection engine with a turbocharger.   2. The engine control method according to claim 1, wherein when the restart condition is satisfied, it is determined whether or not there is a vehicle start request based on at least one operation of a brake, an accelerator, a clutch, and a shift lever of an occupant.   The engine control method according to claim 1, wherein the engine is a multi-cylinder diesel engine.   The engine control method according to any one of claims 1 to 3, wherein the increased amount of fuel is injected in an expansion stroke of the cylinder.   The fuel increase is started from the cylinder in the compression stroke after the compression top dead center of the first cylinder is exceeded after the combustion starts in any of the cylinders at the time of restart. The engine control method as described in one. An engine control device that stops the engine in response to establishment of a predetermined automatic stop condition, and then restarts the engine if a predetermined restart condition is satisfied,
The engine is a multi-cylinder diesel engine including a fuel injection valve that directly injects fuel into a combustion chamber in a cylinder, and a turbocharger that is driven by an exhaust flow to supercharge intake air.
Start request determination means for determining whether or not there is a vehicle start request based on at least one operation of an occupant's brake, accelerator, clutch, and shift lever when the restart condition is satisfied;
When it is determined by the start request determining means that there is a vehicle start request, the amount of fuel consumed when the engine speed rises at the time of restart is greater than when it is determined that there is no start request. And a fuel increasing means for increasing the fuel injection amount to the predetermined cylinder;
A control device for a direct-injection engine with a turbocharger.

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