JP2009209763A - Engine start control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a start control device and a start control method capable of surely starting an engine irrespective of specifications of the engine without using a glow plug. <P>SOLUTION: This device is provided with: an exhaust valve side variable valve gear 61; a start assist means S1-S5 engaging a motor and the engine by a clutch during engine cold start, making the engine corotate by drive of the motor, setting an exhaust valve under full close condition by an exhaust valve side variable valve gear 61, and injecting fuel of prescribed quantity by a fuel injection valve; a heat generation determination means S6-S9 determining whether heat due to self ignition of injected fuel is generated or not; and start fuel injection means S10, S12 releasing full close retention of the exhaust valve by the exhaust valve side variable valve gear when heat due to self ignition of the fuel injected based on the determination result is generated, opening and closing the exhaust valve with synchronizing with engine rotation, and injecting fuel of quantity necessary for engine start by the fuel injection valve. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle engine start control device, and more particularly to a diesel engine start time control device applied to a hybrid vehicle.

  What applies a glow plugless diesel engine to a hybrid vehicle having a motor generator, an engine, a clutch that engages the motor generator with the engine, and a fuel injection device that directly injects fuel into the combustion chamber of the engine Proposed (see Patent Document 1)

In this device, the exhaust valve side variable valve device is provided, the motor is engaged with the engine by a clutch when the engine is cold-started, and the exhaust valve is fully closed by the exhaust valve side variable valve device. In this state, the engine cooling water temperature Tw detected by the water temperature sensor is compared with a predetermined value Tw1, and if the engine cooling water temperature Tw exceeds the predetermined value Tw1, the injected fuel can be self-ignited. The exhaust valve side variable valve device releases the exhaust valve from being fully closed and opens and closes the exhaust valve in synchronism with engine rotation, and the fuel injection valve injects the fuel required for starting the engine. And the engine is started.
Japanese Patent Application Laid-Open No. 2004-324442.

  By the way, as in the technique of Patent Document 1, it is estimated whether or not self-ignition of the combustion chamber gas is possible by comparing the coolant temperature Tw and the predetermined value Tw1, the predetermined value Tw1 for each different engine specification. It is necessary to adapt. For example, when considering an engine having a small-diameter cylinder bore and an engine having a large-diameter cylinder bore, an engine having a small-diameter cylinder bore is easier to cool than an engine having a large-diameter cylinder bore, and the probability of failure of self-ignition increases. When the predetermined value Tw1 is adapted to an engine having a large-diameter cylinder bore, if the predetermined value Tw1 is used as it is for an engine having a small-diameter cylinder bore, the cooling water temperature Tw becomes equal to or higher than the predetermined value Tw1. However, self-ignition may fail and the engine cannot be started. As described above, in the method for estimating whether or not the combustion chamber gas can be self-ignited by comparing the cooling water temperature Tw and the predetermined value Tw1, it is actually self-ignited after estimating that self-ignition is possible. In order to avoid this, if the predetermined value Tw1 is increased, it takes time to start the engine.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a start control device and a start control method capable of reliably starting an engine without using a glow plug and irrespective of the engine specifications.

  The present invention injects fuel directly into a combustion chamber of a motor (51), an engine (1), a clutch (51a) that engages the motor (51) and the engine (1), and the engine (1). A vehicle having a fuel injection valve (15) includes an exhaust valve side variable valve operating device (61), and engages the motor (51) and the engine (1) by a clutch (51a) when the engine is cold started. The engine (1) is rotated by driving the motor (51), the exhaust valve is fully closed by the exhaust valve side variable valve device (61), and a predetermined amount of fuel is injected by the fuel injection valve (15). It is determined whether or not heat is generated due to self-ignition of the injected fuel, and from this determination result, when heat is generated due to self-ignition of the injected fuel, all of the exhaust valves by the exhaust valve side variable valve operating device (61) are determined. Release closed An exhaust valve with opening and closing in synchronism with engine rotation Te, the fuel injection valve (15) configured to inject fuel quantity required for the engine start.

The present invention also provides a motor (51), an engine (1), a clutch (51a) that engages the motor (51) and the engine (1), and a combustion chamber of each cylinder of the engine (1). In a vehicle having a fuel injection valve (15) for injecting fuel, a communication passage (4) that bypasses the combustion chamber of each cylinder and communicates an exhaust passage (3) and an intake passage (2), and this communication passage A communication passage opening device (5) that opens (4), releases the opening and blocks the communication passage, and an exhaust passage (3) downstream of the exhaust passage (3) from which the communication passage (4) is branched. An exhaust passage shut-off device (71) that shuts off and releases the shut-off, and engages the motor (51) with the engine (1) by the clutch (51a) when the engine is cold-started to drive the motor (51). The engine (1) is driven by the exhaust passage The exhaust passage (3) is shut off by the disconnecting device (71) and the communication passage (4) is opened by the communication passage opening device (5), and a predetermined amount of fuel is injected by the fuel injection valve (15) of each cylinder. Then, it is determined whether or not heat generation due to self-ignition of the injected fuel has occurred, and when heat generation due to self-ignition of the injected fuel has occurred based on this determination result, the exhaust passage (3) of the exhaust passage blocking device (71) The shut-off is released, the exhaust passage (3) is fully opened, the opening of the communication passage (4) by the communication passage opening device (5) is released, and the fuel injection valve (15) of each cylinder is required for starting the engine. The fuel amount is injected.
In the present invention, in addition to the hybrid vehicle, the vehicle includes a vehicle that is not a hybrid vehicle. The motor may be a motor generator or a starter motor. The engine may be a diesel engine.

  According to the present invention, in a vehicle having a motor, an engine, a clutch that engages the motor and the engine, and a fuel injection valve that injects fuel directly into the combustion chamber of the engine, an exhaust valve side variable valve operating device. When the engine is cold started, the clutch engages the motor with the engine, and the motor is driven by the motor, and the exhaust valve is fully closed by the exhaust valve side variable valve operating device. A fixed amount of fuel is injected, and it is determined whether or not heat is generated due to self-ignition of the injected fuel. From this determination result, when heat is generated due to self-ignition of the injected fuel, the exhaust valve side variable valve operating device The exhaust valve is released from being fully closed to open and close the exhaust valve in synchronism with engine rotation, and the fuel injection valve injects a fuel amount necessary for starting the engine. That is, by repeatedly compressing the gas in the combustion chamber by the piston, the fuel injected into the combustion chamber evaporates to form a premixed gas, and the temperature of the gas in the combustion chamber rises, leading to self-ignition soon. Can do. And since the amount of fuel required for starting the engine is injected after heat generation due to self-ignition of the injected fuel occurs, even if the engine is in a cold state, it does not use a glow plug and is related to the difference in engine specifications Therefore, the engine can be reliably started.

  Further, according to the present invention, each cylinder in a vehicle having a motor, an engine, a clutch that engages the motor and the engine, and a fuel injection valve that directly injects fuel into the combustion chamber of each cylinder of the engine. A communication passage that bypasses the combustion chamber and communicates the exhaust passage and the intake passage, a communication passage opening device that opens the communication passage, releases the opening, and blocks the communication passage, and the communication passage is branched. An exhaust passage shut-off device that shuts off the exhaust passage downstream of the exhaust passage and releases the shut-off, engages the motor with the engine by a clutch when the engine is cold start, The exhaust passage is shut off by the passage shut-off device and the communication passage is opened by the communication passage opening device, a predetermined amount of fuel is injected by the fuel injection valve of each cylinder, and the injected fuel is self-ignited. From this determination result, when heat generation due to self-ignition of the injected fuel occurs, the exhaust passage blocking device releases the shutoff of the exhaust passage and opens the exhaust passage fully open. The opening of the communication passage by the passage opening device is released, and the fuel amount necessary for starting the engine is injected by the fuel injection valve of each cylinder. That is, by repeatedly compressing the combustion chamber gas of each cylinder by the piston of each cylinder, the fuel injected into the combustion chamber of each cylinder is composed of the combustion chamber, exhaust passage, communication passage, and intake passage of each cylinder. While circulating through the circulation path, it evaporates to form a premixed gas, and the temperature of the gas in the combustion chamber of each cylinder rises. And since the amount of fuel required to start the engine is injected after heat generation due to self-ignition occurs in each cylinder, even if the engine is in a cold state, no glow plug is used and regardless of the difference in engine specifications The engine can be reliably started.

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

  FIG. 1 is a system configuration diagram of a hybrid vehicle to which a startup control apparatus according to a first embodiment of the present invention is applied. As the hybrid vehicle, a parallel hybrid type vehicle is described in which an electric motor and an internal combustion engine are arranged so as to be able to operate independently or in combination for vehicle travel.

  In FIG. 1, the hybrid vehicle travels with two types of power sources, that is, an output of a diesel engine (hereinafter simply referred to as “engine”) 1 and an output of a vehicle drive motor generator 53 that receives power supply from a battery 50. . The output of the engine 1 is transmitted to the start-time motor generator 51 for power generation via the first clutch, and is driven via a differential gear 54 from a power transmission mechanism (for example, CVT) 52 for vehicle driving via the second clutch. It is transmitted to the wheels 55a and 55b. Here, the first clutch and the second clutch are not shown in FIG. 1, but the configuration is the same as that of the second embodiment shown in FIG. That is, the first clutch 51 a is provided between the engine 1 and the starting motor generator 51, and the second clutch 51 b is provided between the starting motor generator 51 and the power transmission mechanism 52.

  Note that the output distribution of the engine 1 used for power generation and vehicle driving is controlled by a hybrid control unit 40. For example, in a relatively low vehicle speed state where the hybrid vehicle starts traveling, traveling (EV traveling) is performed by powering the vehicle drive motor generator 53 while the engine 1 is stopped. The hybrid control unit 40 controls power supply from the battery 50 to the start-up motor generator 51 and the vehicle drive motor generator 53, and at the time of deceleration, regenerative power from the vehicle drive motor generator 53 to the battery 50 is controlled. Collection is also controlled.

  The hybrid control unit 40 monitors vehicle driving information (including stoppage) in order to monitor a signal from the accelerator sensor 41 (an output signal proportional to the amount of depression of the accelerator pedal) and a signal from the start key 42 (Acc position and This signal corresponds to the ON position and does not have a Start position unlike a normal vehicle), a signal from the shift lever position sensor 43, a signal from the brake operation switch 44, a signal from the vehicle speed sensor 45, and a signal from the battery remaining capacity sensor 46 And a signal from the current sensor 47 when the engine is driven are input, the start of the engine 1 and its output distribution are determined based on the input signal, and it is determined whether or not output sharing for vehicle traveling is necessary. Then, a start command and an output sharing command are issued to the engine control unit 30.

  The engine control unit 30 then starts or stops the engine 1 and controls the output of the engine 1 in accordance with a command from the hybrid control unit 40. The engine control unit 30 includes a signal Tw from the water temperature sensor 31, a signal from the crank angle sensor 32 (engine rotational speed Ne and crank angle), a signal from the cylinder discrimination sensor 33 (cylinder discrimination signal) Cyl, a common rail. A signal such as a signal Pcr from the pressure sensor 34 for detecting pressure is input.

  A catalyst 8 is provided immediately downstream of the exhaust manifold 3a to purify the exhaust gas coming out of the engine 1. As the catalyst 8, for example, an oxidation catalyst is supported, and a catalyst in which a precious metal such as Pd or Pt is supported on an activated alumina base, a zeolite in which a precious metal (especially Pt) is ion-exchanged, or a combination of these two materials can be used.

  The EGR valve 5 driven by the stepping motor returns a part of the exhaust gas immediately upstream of the intake manifold 2d via the EGR passage 4 branched from the exhaust passage 3 upstream of the turbocharger turbine 3b. The intake passage 2 is provided with an intake throttle valve 7 that is opened and closed by an air cleaner 2a, a supercharger compressor 2b, an intercooler 2c, and an actuator (for example, a stepping motor type) 6 from the upstream side.

  The fuel supply system includes a diesel fuel (light oil) tank 20, a fuel supply passage 16 for supplying diesel fuel to the fuel injection device 10 of the engine 1, and return fuel (spill fuel) from the fuel injection device 10 of the engine 1. Is constituted by a fuel return passage 19 for returning the fuel to the diesel fuel tank 20. The fuel injection device 10 is a well-known common rail type fuel injection device, which includes a supply pump 11, a common rail (stock pressure chamber) 14, and a fuel injection valve 15 provided for each cylinder, and is pressurized by the supply pump 11. After the fuel is temporarily stored in the common rail 14 via the fuel supply passage 12, the high-pressure fuel in the common rail 14 is distributed to the fuel injection valves 15 corresponding to the number of cylinders.

  Further, in order to control the pressure of the common rail 14, a part of the discharged fuel from the supply pump 11 is returned to the fuel supply passage 16 through an overflow passage 17 provided with a one-way valve 18 in the middle thereof. Here, the pressure control valve 13 is provided in the overflow passage 17. By controlling the pressure control valve 13 in accordance with the duty signal from the engine control unit 30, the flow passage area of the overflow passage 17 is changed. The fuel discharge amount to the common rail 14 is adjusted, and the pressure of the common rail 14 is controlled.

  The fuel injection valve 15 is an electronic fuel injection valve that opens and closes a fuel supply passage to the combustion chamber of the engine 1 in response to an ON-OFF signal from the engine control unit 30, and injects fuel into the combustion chamber by an ON signal. Then, the injection is stopped by the OFF signal. Note that the fuel injection amount increases as the ON signal of the fuel injection valve 15 increases, but also changes depending on the fuel pressure of the common rail 14.

  On the premise of the hybrid vehicle having the above configuration, the present embodiment further includes an exhaust valve side variable valve operating device 61 and an intake valve side variable valve operating device 62. The exhaust valve side variable valve operating device 61 can receive the signal from the engine control unit 30 and control the lift amount and opening / closing timing of the exhaust valve of each cylinder. Similarly, the intake valve side variable valve operating device 62 can control the lift amount and opening / closing timing of the intake valve in response to a signal from the engine control unit 30.

  The glow plug preheats the combustion chamber at the time of cold start of the engine 1 to assist the engine start. However, in this embodiment, the glow plug is not provided facing the combustion chamber of each cylinder. That is, the engine of this embodiment is a glow plugless engine. The idea of making the glow plugless in the hybrid vehicle is that the engine 1 is motorized by the start-up motor generator 51 while the exhaust valve is closed using the exhaust valve side variable valve device 61 at the cold start when the engine is requested to start. By ringing (rotating together), the preheating of the combustion chamber gas of each cylinder is promoted by the sliding frictional heat of the piston of each cylinder and the compression heat by the reciprocating motion of the piston, and the cooling detected by the water temperature sensor 31 in this state The water temperature Tw is compared with a predetermined value Tw1 (for example, 40 ° C.), and when the cooling water temperature Tw exceeds the predetermined value Tw1, it is determined that the preheating of the combustion chamber gas in each cylinder is completed and self-ignition is possible in each cylinder. There is a conventional apparatus that starts fuel injection from the fuel injection valve 15 and starts the engine.

  However, in order to estimate whether or not self-ignition of the combustion chamber gas of each cylinder is possible by comparing the coolant temperature Tw and the predetermined value Tw1 as in the conventional device, the predetermined value Tw1 is set for each different engine specification. Need to fit. For example, when considering an engine having a large-diameter cylinder bore and an engine having a small-diameter cylinder bore, an engine having a small-diameter cylinder bore is more likely to cool than an engine having a large-diameter cylinder bore, and the probability of failure of self-ignition in each cylinder is likely. Therefore, when the predetermined value Tw1 is adapted to an engine having a large-diameter cylinder bore, if the predetermined value Tw1 is used as it is for an engine having a small-diameter cylinder bore, the cooling water temperature Tw is equal to the predetermined value Tw1. Even if it becomes above, self-ignition may fail in each cylinder, and the situation which cannot start an engine can be considered. Thus, in the method of estimating whether or not the combustion chamber gas can self-ignite in each cylinder by comparing the coolant temperature Tw and the predetermined value Tw1, after estimating that each cylinder can self-ignite, Actually, there is a possibility that each cylinder does not self-ignite, and if the predetermined value Tw1 is increased to avoid this, it takes time to start the engine.

  Therefore, in the first embodiment of the present invention, when there is an engine start request and the engine is in a cold state, the intake and exhaust valves of each cylinder are controlled by the variable valve devices 61 and 62 on the exhaust valve side and the intake valve side. While both are closed (fully closed), the start-time motor generator 51 and the engine 1 are engaged by the first clutch 51a (clutch), and the engine 1 is motored (rotated) by the start-time motor generator 51. During engine motoring with the intake and exhaust valves closed, a predetermined amount of fuel is injected from the fuel injection valve 15 into the combustion chamber in each cylinder. By repeatedly compressing the combustion chamber gas by the piston in each cylinder, the fuel injected into the combustion chamber evaporates to form a premixed gas, and the temperature of the combustion chamber gas in each cylinder rises and then each cylinder Can lead to self-ignition. Then, it is determined whether or not heat generation due to self-ignition has occurred in each cylinder, and when it is determined that heat generation due to self-ignition has occurred in each cylinder, an amount of fuel necessary for starting is injected from the fuel injection valve 15. Then, the engine 1 is started.

  As described above, according to the first embodiment of the present invention, since it is determined whether or not heat generation due to self-ignition of the combustion chamber gas occurs in each cylinder, self-ignition fails in each cylinder after the determination of heat generation. Therefore, even if there is no glove lug or intake heater, low temperature startability can be ensured. That is, according to the present invention, the fuel injection at the time of starting the engine is performed in each cylinder after confirming that heat is generated due to the self-ignition of the fuel injected in each cylinder. Therefore, it is possible to reduce the number of conforming man-hours.

  As a method for determining whether or not heat generation due to self-ignition of the injected fuel occurs in each cylinder, either <1> a heat generation determination method based on the pressure in the combustion chamber or <2> a heat generation determination method based on the motor torque Adopt. This will be described below in this order.

<1> Heat Generation Determination Method Based on Combustion Chamber Pressure FIG. A change in the pressure in the combustion chamber (denoted as “in-cylinder pressure” in the figure) in a predetermined crank angle range centering on the compression top dead center for one cylinder is shown. It is No. until the number of repeated compressions (hereinafter simply referred to as “the number of repeated compressions”) from the timing when the engine is requested in the cold engine state until the nth (nth cycle). No self-ignition occurs in one cylinder, and no. When heat generation due to self-ignition occurs in one cylinder, No. The change waveform of the pressure in the combustion chamber of one cylinder changes from the alternate long and short dash line to the solid line. When this is transferred to the heat generation graph shown in FIG. 2B, No. is indicated when the number of repeated compressions is n (n cycles). A straight line indicated by a one-dot chain line with no heat generation in one cylinder becomes a solid line waveform at the (n + 1) th time (n + 1 cycle). That is, when the area between the solid line and the alternate long and short dash line (the area of the hatched portion) is n + 1 times (n + 1 cycle), This represents the amount of heat generated in one cylinder. No. The amount of heat generated at each time (each cycle) in one cylinder is No. in the current technology. No. detected by the pressure sensor 63 attached to one cylinder. It can be easily obtained by using the pressure in the combustion chamber of one cylinder and “heat generation analysis software”.

  In FIG. 2C, the horizontal axis represents the number of times of repeated compression, and the vertical axis represents the integrated value of the heat generation amount from the timing when the engine start request is made in the engine cold state (hereinafter simply referred to as “heat generation amount integrated value”). ) Qsum is taken. This heat generation amount integrated value Qsum is zero immediately after the engine start request in the cold state of the engine, but rises and becomes large after the number of repeated compressions is n + 1 (n + 1 cycle). . Therefore, when the slice level Qsl1 is provided at the position shown in FIG. 2C and the heat generation amount integrated value Qsum exceeds the slice level Qsl1, It can be determined that not only one cylinder but also the remaining cylinders generate heat due to self-ignition.

  Here, it can be said that the position of the slice level Qs11 is closer to zero than the position shown in FIG. 2C, and the heat generation determination timing is earlier, which is preferable. However, heat generation occurs when each cylinder is surely self-ignited. The determination timing is also important, and the position of the slice level Qsl1 is finally determined by adaptation.

<2> Heat Generation Determination Method Based on Motor Torque FIG. 3A shows the change in motor torque with respect to the number of repeated compressions. Here, the “motor torque” refers to the motor torque (motor driving torque) of the start-time motor generator 51 that rotates the engine 1. Since the self-ignition does not occur in any cylinder until the number of repeated compressions is n-th (n-cycle), the motor torque remains at the time of motoring (rated torque), and at any n + 1-th (n + 1-cycle) After self-ignition in one of the cylinders, the motor torque decreases from the motoring torque.

  FIG. 3B shows the characteristics of the heat generation amount integrated value with respect to the motor torque. When the motor torque is the motoring torque, the heat generation amount integrated value is zero, and the heat is increased as the motor torque decreases from the motoring torque. The generated amount integrated value increases. Therefore, a slice level Qsl2 is provided at the position shown in FIG. 3B, and the motor torque is calculated from the voltage value applied to the starting motor generator 51 and the current value supplied to the starting motor generator 51, The heat generation amount integrated value Qsum is calculated by searching a table having the content of FIG. 3B from the motor torque. When the calculated heat generation amount integrated value Qsum exceeds the slice bell Qsl2, it can be determined that heat generation by self-ignition has occurred in each cylinder.

  Here, it can be said that the position of the slice level Qsl2 is preferably closer to zero than the position shown in FIG. 3B, and the heat generation determination timing is earlier, which is preferable. However, heat generation occurs when each cylinder is surely self-ignited. The determination timing is also important, and the position of the slice level Qsl2 is finally determined by adaptation.

  The motor torque of the starting motor generator 51 is calculated based on the supply current value detected when the engine is driven detected by the current sensor 47 and the voltage value (constant) applied to the starting motor generator 51. can do. Therefore, the current sensor 47 is a motor driving torque detection means.

  According to the above method <1>, it is possible to determine whether or not heat generation due to self-ignition has occurred for each cylinder. In the above method <2>, since the engine as a whole is targeted, it cannot be determined whether or not heat generation due to self-ignition has occurred for each cylinder. However, in the method <1>, it is necessary to detect the pressure in the combustion chamber for each cylinder, whereas in the method <2>, a sensor is used to determine whether heat is generated due to self-ignition. It is not necessary to add a new one.

  The heat generation determination method is not limited to the above two cases <1> and <2>. For example, a slice level SL3 is provided at the position shown in FIG. 3A, and when the calculated motor torque becomes smaller than the slice level SL3, it is determined that heat is generated by self-ignition in each cylinder. Can do.

  Next, this control performed by the engine control unit 30 will be described based on the flowchart of FIG. FIG. 4 is for performing engine start control of the hybrid vehicle. This flow is not executed at regular intervals, but the contents of control are arranged in time series.

  However, here, it is assumed that the heat generation determination method is the method <1> above, and the sensor for detecting the pressure is No. 1. It is provided only in one cylinder and the No. detected by this pressure sensor. Based on the pressure in the combustion chamber of one cylinder, No. When it is determined that heat is generated by self-ignition in one cylinder, it is considered that heat is generated by self-ignition in the remaining cylinders, and an amount of fuel necessary for starting is injected from the fuel injection valve 15 of each cylinder. It is assumed that the engine 1 is started. Of course, a pressure sensor is provided in each cylinder, and after determining that heat is generated due to self-ignition in all the cylinders, an amount of fuel necessary for starting is injected from the fuel injection valve 15 of each cylinder, and the engine 1 You may make it start.

  In step 1, it is determined whether there is an engine start request. For example, the engine start request is commanded from the hybrid control unit 40 to the engine control unit 30 when the vehicle traveling torque is insufficient only by EV traveling or when the battery 50 is requested to be charged. When there is no command for an engine start request from the hybrid control unit 40, the process waits as it is.

  When there is an engine start request command from the hybrid control unit 40, the process proceeds to step 2 to check whether or not the engine cooling water temperature Tw detected by the water temperature sensor 31 is in a cold state equal to or lower than a predetermined value Tw2. Here, the predetermined value Tw2 is a value for determining whether or not the engine is in a cold state, and is adapted in advance. When the engine coolant temperature Tw exceeds the predetermined value Tw2, that is, when the engine cooling water temperature Tw is not cold, an operation for assisting the start is not necessary, so the routine proceeds to steps 11 and 12, and a known engine (see, for example, JP-A-2003-20981) Start operation. That is, in step 11, drive control of the pressure control valve 13 is performed so that the common rail pressure is stored in advance in the ROM and set according to the motoring rotational speed of the engine 1. In step 12, the fuel injection valve 15 is controlled in order to inject and supply to the engine 1 a fuel amount stored in advance in the ROM and set in accordance with the coolant temperature Tw.

  On the other hand, when there is an engine start request and the engine is cold (cooling water temperature Tw is equal to or lower than a predetermined value Tw2), the routine proceeds to steps 3 to 9, and the engine start assist operation according to the present invention is performed.

  First, in step 3, the intake and exhaust valves of each cylinder are kept closed by the variable valve gears 61 and 62 on the exhaust valve side and the intake valve side (fully closed state). 1 is engaged by a first clutch 51a (clutch), and the engine 1 is motored by the start-time motor generator 51 (the engine 1 is rotated by the start-time motor generator 51). In step 5, a predetermined amount of fuel is injected from the fuel injection valve 15 of each cylinder into the combustion chamber. In this case, the predetermined amount is set so that the excess air ratio of the combustion chamber gas of each cylinder becomes the excess air ratio at which normal diesel combustion (lean combustion) is performed.

  The present invention is not limited to the mode in step 3, and only the exhaust valve of each cylinder is brought into the fully closed state, that is, the intake valve of each cylinder is opened and closed in synchronism with engine rotation. The gas in the combustion chamber may once return to the intake port of each cylinder. In addition, fuel injection from the fuel injection valve in each cylinder injects a predetermined amount of fuel at a time when there is an engine start request and the engine is cold, and the predetermined amount of fuel is divided over multiple cycles. You may make it inject. Rather than injecting a predetermined amount of fuel into each cylinder at a time when the engine is cold, the amount of fuel adhering to the combustion chamber wall of each cylinder is less when it is divided and injected over multiple cycles in each cylinder. The time until ignition can be shortened.

In step 6, the No. detected by the pressure sensor 63 is detected. Read the pressure in the combustion chamber of one cylinder, Using the “Heat generation analysis software” from the pressure in the combustion chamber of one cylinder, No. The amount of heat generation Q1 per cylinder is calculated. A heat generation amount integrated value Qsum of one cylinder is calculated.
Qsum = Qsum (previous) + Q1 (1)
However, Qsum (previous): previous value of Qsum,

  Here, the initial value of “Qsum (previous)” is set to zero when the engine is automatically stopped.

  In step 9, this No. The one-cylinder heat generation amount integrated value Qsum and the slice level Qsl1 are compared. In step 4, the engine 1 and the motor generator 51 for start-up are engaged and motoring of the engine 1 is started by the motor generator 51 for start-up at the beginning. The gas temperature in the combustion chamber of one cylinder is low. The fuel injected into the combustion chamber of one cylinder does not self-ignite (that is, no heat is generated in No. 1 cylinder). The heat generation amount integrated value Qsum of one cylinder is zero. At this time, the process returns to step 6 and the operations of steps 6, 7, and 8 are repeated. That is, when motoring by the start-time motor generator 51 is repeated with the intake and exhaust valves of each cylinder closed and a predetermined amount of fuel injected into the combustion chamber of each cylinder, the cylinders are reciprocated by the reciprocating motion of each cylinder. Since the compression and expansion are repeated at this time, the combustion chamber gas of each cylinder is warmed, and the fuel injected into each cylinder is vaporized to become a mixture, and eventually, self-ignition occurs in each cylinder and heat is generated. Due to this heat generation, the No. The heat generation amount Q1 of one cylinder takes a positive value, and accordingly, No. The accumulated heat generation value Qsum of one cylinder increases with a positive value. The heat generation amount integrated value Qsum of one cylinder exceeds the slice level Qsl1. At this time, no. It is determined that heat is generated due to self-ignition in one cylinder, and therefore it is considered that heat is also generated due to self-ignition in the remaining cylinders. The intake / exhaust valves of the cylinders are released from being fully closed by the variable valve gears 61 and 62 on the side so that the intake / exhaust valves of the cylinders open and close in synchronization with the engine rotation. The engine is started (common rail pressure control at start-up and fuel injection amount control at start-up).

  Here, the effect of this embodiment is demonstrated.

  According to the present embodiment (the invention described in claims 1, 8, and 10), the starting motor generator 51 (motor), the engine 1, and the starting motor generator 51 and the engine 1 are engaged. A vehicle having a first clutch 51a (clutch) and a fuel injection valve 15 that directly injects fuel into the combustion chamber of the engine 1 includes an exhaust valve side variable valve operating device 61, and the first clutch at the time of cold start of the engine The motor generator 51 for start-up is engaged with the engine 1 by 51a, the engine 1 is driven by driving the motor generator 51 for start-up (see step 4 in FIG. 4), and exhaust is performed by the variable valve operating device 61 on the exhaust valve side. With the valve fully closed (see step 3 in FIG. 4), a predetermined amount of fuel is injected by the fuel injection valve 15 (see step 5 in FIG. 4). It is determined whether or not heat generation due to fuel self-ignition has occurred (see Steps 6 to 9 in FIG. 4), and when heat generation due to self-ignition of injected fuel occurs based on this determination result, the exhaust valve side variable valve operating device The exhaust valve 61 is released from the fully closed state to open and close the exhaust valve in synchronism with the engine rotation (see step 10 in FIG. 4), and the fuel injection valve injects a fuel amount necessary for starting the engine (see FIG. 4). (See step 12 in FIG. 4). That is, by repeatedly compressing the gas in the combustion chamber by the piston, the fuel injected into the combustion chamber evaporates to form a premixed gas, and the temperature of the gas in the combustion chamber rises, leading to self-ignition soon. Can do. Since the fuel amount necessary for starting the engine is injected after heat is generated by the self-ignition of the injected fuel, even if the engine 1 is in a cold state, the glow plug is not used and the engine specification is different. Regardless, the engine can be reliably started.

  According to the present embodiment (the invention described in claim 4), the predetermined amount of fuel injection in the start assist means is performed by split injection over a plurality of cycles by the fuel injection valve 15, so that the engine is in a cold state. Rather than injecting a fixed amount of fuel at a time, split injection over a plurality of cycles results in less fuel adhering to the wall surface of the combustion chamber, and accordingly, the time until self-ignition can be shortened.

  According to the present embodiment (the invention described in claim 5), the pressure sensor 63 (pressure detection means) is provided, and the heat generation determination means is the fuel injection based on the pressure in the combustion chamber detected by the pressure sensor 63. Since it is determined whether or not heat generation due to self-ignition has occurred (see Steps 6 to 9 in FIG. 4), in the case of a multi-cylinder engine, whether or not heat generation due to self-ignition of injected fuel has occurred is determined for each cylinder. be able to.

  According to this embodiment (the invention described in claim 6), the current sensor 47 (motor drive torque detecting means) is provided, and the heat generation determining means is the supply current value at the time of engine rotation detected by the current sensor 47. Since it is determined whether or not heat generation due to self-ignition of the injected fuel has occurred based on (corresponding to the motor drive torque), a new sensor is used to determine whether or not heat generation due to self-ignition of the injected fuel has occurred. It is not necessary to add, and the cost can be reduced.

  Next, FIG. 5 is a system configuration diagram of a hybrid vehicle to which the start time control device according to the second embodiment of the present invention is applied. In the second embodiment, neither the exhaust valve side variable valve device nor the intake valve side variable valve device is provided. Therefore, the intake and exhaust valves are opened and closed for each cylinder in synchronization with the engine rotation. Instead, an EGR passage 4 from the exhaust passage 3 (a communication passage that bypasses the combustion chamber of each cylinder and communicates the exhaust passage and the intake passage) immediately downstream of the branch portion is based on a signal from the engine control unit 30. A normally-open exhaust shut valve 71 (exhaust passage shut-off device) that shuts off the exhaust passage 3 is provided. In addition, the same number is attached | subjected to the same part as FIG. Some parts of FIG. 1 are omitted.

  In the second embodiment, when there is an engine start request and the engine is in a cold state, the EGR valve 5 (communication path opening device) is fully opened and the exhaust shut-off valve 71 is fully closed. The motor generator 51 and the engine 1 are engaged by a first clutch 51 a (clutch), and the engine 1 is motored (rotated) by the start-up motor generator 51. During engine motoring with the EGR valve 5 fully opened and the exhaust shut valve 71 fully closed, a predetermined amount of fuel is injected from the fuel injection valve 15 into the combustion chamber of each cylinder.

  By setting the EGR valve 5 to the fully open state and the exhaust shut valve 71 to the fully closed state, the combustion chamber gas of each cylinder that has come out from the exhaust port to the exhaust manifold 3 a by the opening of the exhaust valve is taken in via the EGR passage 4. In the cylinder in which the intake valve is opened after being returned to the manifold 2d, the gas in the intake manifold 2d is again sucked from the intake port of the cylinder into the combustion chamber of the cylinder. An exhaust port of each cylinder, an exhaust manifold 3a, an EGR passage 4, an intake manifold 2d, and an intake port of each cylinder form a combustion chamber gas circulation path.

  While the combustion chamber gas is circulated through the circulation path composed of the exhaust port, the exhaust manifold 3a, the EGR passage 4, the intake manifold 2d, and the intake port, the compression of the combustion chamber gas is repeatedly performed by the piston in each cylinder. The fuel injected into the combustion chamber evaporates while circulating in the above-mentioned circulation path to form a premixed gas, and the temperature of the combustion chamber gas in each cylinder rises and eventually self-ignition occurs in each cylinder. it can. Then, it is determined whether or not heat generation due to self-ignition has occurred in each cylinder, and when it is determined that heat generation due to self-ignition has occurred in each cylinder, an amount of fuel necessary for starting is injected from the fuel injection valve 15. Then, the engine 1 is started.

  As a method for determining whether or not heat generation due to self-ignition has occurred in each cylinder, any of the methods <1> and <2> described above in the first embodiment may be employed. In the second embodiment, the following heat generation determination method <3> is adopted. This heat generation determination method will be described.

<3> Heat Generation Determination Method Based on Combustion Chamber Gas Temperature FIG. 6A is a combustion chamber gas temperature with respect to the number of repeated compressions when focusing on one cylinder (for example, No. 1 cylinder) (in the figure, simply “gas temperature”). Change). No. until the number of repeated compressions is n-th (n cycles). No self-ignition occurs in one cylinder. The change in gas temperature in the combustion chamber of one cylinder is small, and No. After heat generation by self-ignition occurs in one cylinder, No. The gas temperature in the combustion chamber of one cylinder suddenly increases. In this case, no. The rate of change in the temperature of the combustion chamber gas for one cylinder (the first derivative value of the temperature of the combustion chamber gas for No. 1 cylinder). The amount of change in the temperature change rate of the combustion chamber gas for one cylinder (the second derivative value of the gas temperature in the combustion chamber for No. 1 cylinder) is shown in FIGS. 6 (B) and 6 (C). No. Change rate of gas temperature in combustion chamber of one cylinder, No. The amount of change in the temperature change rate of the gas in the combustion chamber of one cylinder has changed greatly. In particular, No. 1 shown in FIG. Looking at the amount of change in the temperature change rate of the gas in the combustion chamber of one cylinder, a negative value until the nth time is greatly changed to a positive value at the (n + 1) th time. Therefore, No. 1 shown in FIG. If the slice level SL4 is provided at the position shown in the figure with respect to the change amount of the gas temperature change rate of one cylinder, no. When the amount of change in the temperature change rate of the gas in the combustion chamber of one cylinder exceeds this slice level SL4, no. It can be determined that not only one cylinder but also the remaining cylinders generate heat due to self-ignition.

  Here, no. The gas temperature in the combustion chamber of one cylinder is No. What is necessary is just to detect with the gas temperature sensor attached facing the combustion chamber of 1 cylinder, No. detected by this gas temperature sensor. Based on the gas temperature in the combustion chamber of one cylinder, No. The amount of change in the temperature change rate of the combustion chamber gas for one cylinder is calculated.

  According to the above method <3>, it is possible to determine for each cylinder whether heat generation due to self-ignition has occurred.

  The above methods <1> and <2> are methods for determining whether heat generation due to self-ignition has occurred based on the heat generation amount integrated value Qsum after obtaining the heat generation amount integrated value Qsum. On the other hand, the method <3> is a method for determining whether or not heat generation due to self-ignition has occurred based on the gas temperature in the combustion chamber without directly obtaining the heat generation amount integrated value. The method <3> can also be applied to the first embodiment. That is, in the first embodiment, the method <3> may be used instead of the methods <1> and <2>.

  Next, this control performed by the engine control unit 30 will be described based on the flowchart of FIG. FIG. 7 is for performing engine start control of the hybrid vehicle of the second embodiment, and replaces FIG. 4 of the first embodiment. The same steps as those in FIG. 4 are given the same step numbers. This flow is not executed at regular intervals, but the contents of control are arranged in time series.

  Here, the heat generation determination method is the method <3> described above, and the gas temperature sensor 72 is provided only in one cylinder (for example, No. 1 cylinder). Based on the gas temperature in the combustion chamber of one cylinder, No. When it is determined that heat is generated by self-ignition in one cylinder, it is considered that heat is generated by self-ignition in the remaining cylinders, and an amount of fuel necessary for starting is injected from the fuel injection valve 15 of each cylinder. It is assumed that the engine 1 is started. Of course, a gas temperature sensor is provided in each cylinder, and after determining that heat is generated due to self-ignition in all the cylinders, an amount of fuel required for starting is injected from the fuel injection valve 15 of each cylinder, and the engine 1 You may make it start.

  The mounting position of the gas temperature sensor 72 is not limited to the combustion chamber, but may be any temperature that can be identified with the gas temperature in the combustion chamber. Therefore, the combustion chamber of each cylinder, the exhaust port of each cylinder, the exhaust manifold 3a, EGR The gas temperature sensor 72 may be provided at any position in the circulation path including the passage 4, the intake manifold 2d, and the intake port of each cylinder. In the second embodiment, the gas is supplied to the exhaust manifold 3a as shown in FIG. The case where the temperature sensor 72 is provided is shown.

  In FIG. 7, the difference from FIG. 4 will be mainly described. When there is an engine start request and the engine is cold, the process proceeds from steps 1 and 2 to steps 21 and 4, and the EGR valve 5 is fully opened (open state). And with the exhaust shut-off valve 71 fully closed, the start-time motor generator 51 and the engine 1 are engaged by the first clutch 51a (clutch), and the engine 1 is motored by the start-time motor generator 51. (Take it around). In step 5, during the engine motoring with the EGR valve 5 fully opened and the exhaust shut valve 71 fully closed, a predetermined amount of fuel is injected from the fuel injection valve 15 of each cylinder into the combustion chamber of each cylinder. . Here again, the fuel injection from the fuel injection valve 15 of each cylinder is performed at a time when there is an engine start request and the engine is cold, and a predetermined amount of fuel is injected over a plurality of cycles. You may make it carry out divided injection.

  In step 22, the No. detected by the gas temperature sensor 72. The combustion chamber gas temperature Tgas of one cylinder is read. No. 1 which is the first derivative value of the gas temperature in the combustion chamber of one cylinder. A rate of change in gas temperature in the combustion chamber for one cylinder dTgas is calculated. In step 24, this No. From the one-cylinder combustion chamber gas temperature change rate dTgas, no. No. 1 which is the second derivative value of the gas temperature in the combustion chamber of one cylinder. A change amount d2Tgas of the rate of change in gas temperature in the combustion chamber of one cylinder is calculated.

  In step 25, this No. The change amount d2Tgas of the rate of change in the temperature of the combustion chamber gas for one cylinder is compared with the slice level SL4. In step 4, the engine 1 and the motor generator 51 for start-up are engaged and motoring of the engine 1 is started by the motor generator 51 for start-up at the beginning. The temperature of the gas in the combustion chamber of one cylinder is low and no self-ignition occurs. No heat is generated in one cylinder. The amount of change d2Tgas of the rate of change in the temperature of the combustion chamber gas for one cylinder is a negative value (see FIG. 6C). At this time, the process returns to step 22 and the operations of steps 22, 23 and 24 are repeated. That is, when the EGR valve 5 is fully opened, the exhaust shut valve 71 is fully closed, and a predetermined amount of fuel is injected into the combustion chamber of each cylinder, the motoring is repeated while circulating the combustion chamber gas through the circulation path. Since the compression and expansion of each cylinder are repeated by the reciprocation of the piston of each cylinder, the gas in the combustion chamber of each cylinder is warmed and the injected fuel is vaporized to become an air-fuel mixture, and eventually, each cylinder self-ignites and generates heat. . Due to this heat generation, the No. The amount of change d2Tgas of the rate of change in the temperature of the combustion chamber gas in one cylinder exceeds the slice level SL4. At this time, no. It is determined that heat generation due to self-ignition has occurred in one cylinder, and therefore the remaining cylinders are regarded as having generated heat due to self-ignition, and the routine proceeds to step 26 to cancel the start-up assistance and release the fully opened state of the EGR valve 5. The exhaust shut-off valve 71 is returned from the fully closed state to the fully open state. Thereafter, the process proceeds to steps 11 and 12, and known starting operations (starting common rail pressure control and starting fuel injection amount control) are performed.

  As described above, according to the second embodiment (the invention described in claims 3, 9 and 11), the start-time motor generator 51 (motor), the engine 1, the start-time motor generator 51, and the engine 1 In a vehicle having a first clutch 51a (clutch) that engages and a fuel injection valve 15 that directly injects fuel into the combustion chamber of each cylinder of the engine 1, an EGR passage 4 (bypassing the combustion chamber and an exhaust passage) A communication passage that communicates with the intake passage), an EGR valve 5 (a communication passage opening device that opens the communication passage and releases the opening thereof to block the communication passage), and an exhaust shut valve 71 (an exhaust gas that branches the communication passage). An exhaust passage shut-off device that shuts off the exhaust passage downstream of the passage and releases the shut-off), and the start-time motor generator 51 and the engine 1 by the first clutch 51a when the engine is cold-started. The engine 1 is rotated by driving the motor generator 51 for starting (see step 4 in FIG. 7), the exhaust passage 3 is shut off by the exhaust shut valve 71, and the EGR passage 4 is opened by the EGR valve 5. (Open), a predetermined amount of fuel is injected by the fuel injection valve 15 of each cylinder (see step 5 in FIG. 7), and it is determined whether heat generation due to self-ignition of the injected fuel has occurred (FIG. 7). Steps 22 to 25 of FIG. 7), when heat is generated by the self-ignition of the injected fuel based on the determination result, the exhaust passage 3 is released from being shut off by the exhaust shut-off valve 71 and the exhaust passage 3 is fully opened (see FIG. 7). Step 26), the opening of the EGR passage 4 by the EGR valve 5 is released and the EGR passage 4 is shut off (see Step 26 in FIG. 7), and the engine is driven by the fuel injection valve 15 of each cylinder. And injected fuel amount required to start (see step 12 in FIG. 7). That is, by repeatedly compressing the combustion chamber gas of each cylinder by the piston of each cylinder, the fuel injected into the combustion chamber of each cylinder becomes the combustion chamber of each cylinder, the exhaust port of each cylinder, the exhaust manifold 3a, While circulating through the circulation path composed of the EGR passage 4, the intake manifold 2d, and the intake port of each cylinder, it evaporates to form a premixed gas, and the temperature of the combustion chamber gas of each cylinder rises, and then the self-ignition in each cylinder Can be reached. In addition, since the amount of fuel required for starting the engine is injected after heat is generated by self-ignition in each cylinder, even if the engine 1 is in a cold state, it does not use a glow plug and is related to the difference in engine specifications. Therefore, the engine can be reliably started.

  According to the second embodiment (the invention described in claim 7), the gas temperature sensor 72 (gas temperature detection means) is provided, and the heat generation determination means is based on the gas temperature in the combustion chamber detected by the gas temperature sensor 72. Since it is determined whether or not heat generation due to self-ignition of the injected fuel has occurred (see steps 22 to 25 in FIG. 7), whether or not heat generation due to self-ignition of the injected fuel has occurred is determined for each cylinder. Can do.

  In the second embodiment, the EGR passage 4 is used as a communication passage that bypasses the combustion chamber of each cylinder and connects the exhaust passage and the intake passage. However, separately from the EGR passage 4, the combustion chamber of each cylinder is bypassed. You may provide the communicating path which connects an exhaust passage and an intake passage, and the communicating path opener which open | releases this communicating path, cancels | releases the opening, and interrupts | blocks a communicating path.

  By performing engine start-up control as described above, good start-up performance can be ensured even when a diesel engine is applied to a hybrid vehicle. Note that the start-time control device according to the present invention can be applied not only to parallel hybrid vehicles but also to series hybrid vehicles.

  The start time control device according to the present invention can be applied not only to a hybrid vehicle but also to a vehicle having a normal diesel engine. In this case, for example, when there is an engine start request and the engine is in a cold state, the intake and exhaust valves of each cylinder are closed by the variable valve operating devices 61 and 62 on the exhaust valve side and the intake valve side. In this state, the starter motor is engaged with the engine, and the engine is motored (rotated) with the starter motor. A fixed amount of fuel will be injected into the combustion chamber.

  The functions of the auxiliary starting means according to claims 1, 8, and 10 are shown in steps 3 to 5 of FIG. 4, the function of the heat generation determining means is shown in steps 6 to 9 of FIG. 4 steps 10 and 12, respectively.

  The functions of the start assisting means according to claims 3, 9, and 11 are performed according to steps 21, 4 and 5 in FIG. 7, and the function of the heat generation determining means is performed according to steps 22 to 25 in FIG. Is accomplished by steps 26 and 12 of FIG.

1 is a system configuration diagram of a hybrid vehicle according to a first embodiment of the present invention. The characteristic view for demonstrating the heat generation determination method based on a combustion chamber pressure. The characteristic view for demonstrating the heat generation determination method based on a motor torque. The flowchart for demonstrating the engine starting time control of 1st Embodiment. The system block diagram of the hybrid vehicle of 2nd Embodiment. The characteristic view for demonstrating the heat generation determination method based on the gas temperature in a combustion chamber. The flowchart for demonstrating the engine starting time control of 2nd Embodiment.

Explanation of symbols

1 Engine 4 EGR passage (communication passage)
5 EGR valve (communication passage opening device)
DESCRIPTION OF SYMBOLS 15 Fuel injection valve 30 Engine control unit 31 Water temperature sensor 40 Hybrid control unit 47 Current sensor (motor drive torque detection means)
51 Motor generator (motor) for starting
51a First clutch (clutch)
61 Exhaust valve side variable valve operating device 62 Intake valve side variable valve operating device 63 Pressure sensor (pressure detecting means)
71 Exhaust shut valve (exhaust passage shut-off device)
72 Gas temperature sensor (gas temperature detection means)

Claims (13)

In a vehicle having a motor, an engine, a clutch that engages the motor and the engine, and a fuel injection valve that injects fuel directly into the combustion chamber of the engine,
An exhaust valve side variable valve operating device;
When the engine is started, the motor and the engine are engaged by a clutch, the engine is rotated by driving the motor, the exhaust valve is fully closed by the exhaust valve side variable valve device, and a predetermined amount of fuel is injected by the fuel injection valve. Starting assistance means,
Heat generation determination means for determining whether heat generation has occurred due to self-ignition of the injected fuel;
From this determination result, when heat is generated due to self-ignition of the injected fuel, the exhaust valve side variable valve device releases the exhaust valve from being fully closed, and the exhaust valve is opened and closed in synchronization with the engine rotation. An engine start control device for a vehicle, comprising: a start time fuel injection means for injecting a fuel amount required for starting the engine by a valve.   An intake valve-side variable valve device is provided, and when the exhaust valve is fully closed by the exhaust valve-side variable valve device, the intake valve is also fully closed by the intake valve-side variable valve device. The engine start control device for a vehicle according to claim 1. In a vehicle having a motor, an engine, a clutch that engages the motor and the engine, and a fuel injection valve that directly injects fuel into the combustion chamber of each cylinder of the engine,
A communication passage that bypasses the combustion chamber of each cylinder and communicates the exhaust passage and the intake passage;
A communication path opening device that opens the communication path, releases the opening, and blocks the communication path;
An exhaust passage shut-off device that shuts off the exhaust passage downstream of the exhaust passage from which the communication passage is branched and releases the shut-off;
When the engine is started, the motor and the engine are engaged by the clutch, the engine is rotated by driving the motor, the exhaust passage is shut off by the exhaust passage shut-off device, and the communication passage is opened by the communication passage opening device. Start auxiliary means for injecting a predetermined amount of fuel by means of an injection valve;
Heat generation determination means for determining whether heat generation has occurred due to self-ignition of the injected fuel;
Based on the determination result, when heat is generated by the self-ignition of the injected fuel, the exhaust passage is shut off by the exhaust passage shut-off device so that the exhaust passage is fully opened, and the communication passage is opened by the communication passage opening device. And a start-up fuel injection means for injecting a fuel amount required for starting the engine by a fuel injection valve of each cylinder.   The engine start control device for a vehicle according to claim 1 or 3, wherein a predetermined amount of fuel injection in the start assist means is performed by split injection over a plurality of cycles by a fuel injection valve. Pressure detecting means for detecting the pressure in the combustion chamber,
The said heat generation determination means determines whether the heat generation by the self-ignition of the injected fuel has occurred based on the pressure in the combustion chamber detected by this pressure detection means. Vehicle engine start control device. Motor drive torque detecting means for detecting the motor drive torque;
The heat generation determination means determines whether or not heat generation due to self-ignition of the injected fuel has occurred based on the motor drive torque detected by the motor drive torque detection means. The vehicle engine start control device according to claim. Comprising gas temperature detecting means for detecting the gas temperature in the combustion chamber;
The said heat generation determination means determines whether the heat generation by self-ignition of the injected fuel has occurred based on the gas temperature in the combustion chamber detected by the gas temperature detection means. Vehicle engine start control device. In a vehicle having a motor generator, an engine, a clutch for engaging the motor generator and the engine, and a fuel injection valve for directly injecting fuel into a combustion chamber of the engine,
An exhaust valve side variable valve operating device;
When there is an engine start request and the engine is in a cold state, the motor generator and the engine are engaged by a clutch, the engine is driven by driving the motor generator, and the exhaust valve is fully closed by an exhaust valve side variable valve operating device. As a state, start assisting means for injecting a predetermined amount of fuel by a fuel injection valve,
Heat generation determination means for determining whether heat generation has occurred due to self-ignition of the injected fuel;
From this determination result, when heat is generated due to self-ignition of the injected fuel, the exhaust valve side variable valve device releases the exhaust valve from being fully closed, and the exhaust valve is opened and closed in synchronization with the engine rotation. An engine start control device for a vehicle, comprising: a start time fuel injection means for injecting a fuel amount required for starting the engine by a valve. In a vehicle having a motor generator, an engine, a clutch that engages the motor generator and the engine, and a fuel injection valve that directly injects fuel into the combustion chamber of each cylinder of the engine,
A communication passage that bypasses the combustion chamber of each cylinder and communicates the exhaust passage and the intake passage;
A communication path opening device that opens the communication path, releases the opening, and blocks the communication path;
An exhaust passage shut-off device that shuts off the exhaust passage downstream of the exhaust passage from which the communication passage is branched and releases the shut-off;
When there is an engine start request and the engine is cold, the motor generator and the engine are engaged by a clutch, the engine is driven by driving the motor generator, the exhaust passage is shut off by the exhaust passage shut-off device, and the communication passage Start auxiliary means for opening a communication path by an opening device and injecting a predetermined amount of fuel by a fuel injection valve of each cylinder;
Heat generation determination means for determining whether heat generation has occurred due to self-ignition of the injected fuel;
Based on the determination result, when heat is generated by the self-ignition of the injected fuel, the exhaust passage is shut off by the exhaust passage shut-off device so that the exhaust passage is fully opened, and the communication passage is opened by the communication passage opening device. And a start-up fuel injection means for injecting a fuel amount required for starting the engine by a fuel injection valve of each cylinder. In a vehicle having a motor, an engine, a clutch that engages the motor and the engine, and a fuel injection valve that injects fuel directly into the combustion chamber of the engine,
Equipped with an exhaust valve side variable valve operating device,
When the engine is started, the motor and the engine are engaged by a clutch, the engine is rotated by driving the motor, the exhaust valve is fully closed by the exhaust valve side variable valve device, and a predetermined amount of fuel is injected by the fuel injection valve. Start-up assistance procedure,
A heat generation determination processing procedure for determining whether heat generation has occurred due to self-ignition of the injected fuel;
From this determination result, when heat is generated due to self-ignition of the injected fuel, the exhaust valve side variable valve device releases the exhaust valve from being fully closed, and the exhaust valve is opened and closed in synchronization with the engine rotation. And a starting fuel injection processing procedure for injecting an amount of fuel required for starting the engine with a valve. In a vehicle having a motor, an engine, a clutch that engages the motor and the engine, and a fuel injection valve that directly injects fuel into the combustion chamber of each cylinder of the engine,
A communication passage that bypasses the combustion chamber of each cylinder and communicates the exhaust passage and the intake passage;
A communication path opening device that opens the communication path, releases the opening, and blocks the communication path;
An exhaust passage shut-off device that shuts off the exhaust passage downstream of the exhaust passage from which the communication passage is branched and releases the shut-off.
When the engine is started, the motor and the engine are engaged by the clutch, the engine is rotated by driving the motor, the exhaust passage is shut off by the exhaust passage shut-off device, and the communication passage is opened by the communication passage opening device. A start assist processing procedure for injecting a predetermined amount of fuel by an injection valve;
A heat generation determination processing procedure for determining whether heat generation has occurred due to self-ignition of the injected fuel;
Based on the determination result, when heat is generated by the self-ignition of the injected fuel, the exhaust passage is shut off by the exhaust passage shut-off device so that the exhaust passage is fully opened, and the communication passage is opened by the communication passage opening device. And a starting fuel injection processing procedure for injecting a fuel amount required for starting the engine by a fuel injection valve of each cylinder. In a vehicle having a motor generator, an engine, a clutch for engaging the motor generator and the engine, and a fuel injection valve for directly injecting fuel into a combustion chamber of the engine,
Equipped with an exhaust valve side variable valve operating device,
When there is an engine start request and the engine is in a cold state, the motor generator and the engine are engaged by a clutch, the engine is driven by driving the motor generator, and the exhaust valve is fully closed by an exhaust valve side variable valve operating device. As a state, a start assist processing procedure for injecting a predetermined amount of fuel by the fuel injection valve,
A heat generation determination processing procedure for determining whether heat generation has occurred due to self-ignition of the injected fuel;
From this determination result, when heat is generated due to self-ignition of the injected fuel, the exhaust valve side variable valve device releases the exhaust valve from being fully closed, and the exhaust valve is opened and closed in synchronization with the engine rotation. And a starting fuel injection processing procedure for injecting an amount of fuel required for starting the engine with a valve. In a vehicle having a motor generator, an engine, a clutch that engages the motor generator and the engine, and a fuel injection valve that directly injects fuel into the combustion chamber of each cylinder of the engine,
A communication passage that bypasses the combustion chamber of each cylinder and communicates the exhaust passage and the intake passage;
A communication path opening device that opens the communication path, releases the opening, and blocks the communication path;
An exhaust passage shut-off device that shuts off the exhaust passage downstream of the exhaust passage from which the communication passage is branched and releases the shut-off.
When there is an engine start request and the engine is cold, the motor generator and the engine are engaged by a clutch, the engine is driven by driving the motor generator, the exhaust passage is shut off by the exhaust passage shut-off device, and the communication passage A starting auxiliary processing procedure for opening a communication path by an opening device and injecting a predetermined amount of fuel by a fuel injection valve of each cylinder;
A heat generation determination processing procedure for determining whether heat generation has occurred due to self-ignition of the injected fuel;
Based on the determination result, when heat is generated by the self-ignition of the injected fuel, the exhaust passage is shut off by the exhaust passage shut-off device so that the exhaust passage is fully opened, and the communication passage is opened by the communication passage opening device. And a starting fuel injection processing procedure for injecting a fuel amount required for starting the engine by a fuel injection valve of each cylinder.

Images