JP5658205B2 - Start control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a start control device for an internal combustion engine that uses various fuels composed of gasoline and alcohol (ethanol).

  Alcohol fuel is less likely to cause knocking, so that the compression ratio can be set high and combustion efficiency can be improved. On the other hand, engine startability is poor when the engine is cold. Therefore, the technique described in Patent Document 1 includes a first injector capable of injecting a first fuel and a second injector capable of injecting a second fuel. Control is performed so that fuel is injected from only one of the two injectors, more specifically, when the engine temperature is low, gasoline fuel is injected from the first injector.

JP 2007-154881 A

  In the technique described in Patent Document 1, by configuring as described above, the deterioration of the operation of the internal combustion engine is suppressed by using an injector most suitable for the situation of starting and warming up in the internal combustion engine using various fuels. I am aiming for that.

  By the way, when the expected alcohol fuel (alcohol concentration) cannot be obtained, it is easy to cause knocking if the compression ratio is kept high. Therefore, it is effective to change the opening / closing timing of the intake valve using the variable valve opening / closing timing mechanism. Although a configuration that lowers the compression ratio is conceivable, the technique described in Patent Document 1 does not assume a case where such a configuration is provided, and there is still room for improvement in that respect.

  Accordingly, the object of the present invention is to solve the above-mentioned problems, and in the internal combustion engine provided with the first and second injectors and the valve opening / closing timing variable mechanism capable of injecting various fuels and alcohol fuel having a higher octane number, startability at the time of cold operation. An object of the present invention is to provide a control device for an internal combustion engine that improves the engine.

In order to achieve the above object, in claim 1, a first injector capable of injecting various fuels including alcohol, a second injector capable of injecting alcohol fuel having an octane number higher than that of the various fuels, and combustion A valve opening / closing timing variable mechanism capable of changing the opening / closing timing of the intake valve that opens / closes the chamber, and burns an air-fuel mixture obtained by mixing the fuel injected from at least one of the first and second injectors with the intake air In an internal combustion engine start control device that generates an output by ignition and combustion in a chamber, when starting the internal combustion engine, the engine temperature detecting means for detecting the engine temperature of the internal combustion engine and the valve opening / closing timing variable mechanism fail. Whether the first and second injectors are based on the detected engine temperature and the determination result of the failure determination means. Flow rate calculating means for calculating the flow rate of fuel to be injected, and fuel injection control means for controlling fuel injection of the first and second injectors at the time of starting the internal combustion engine so as to be the calculated fuel flow rate. And the flow rate calculation means, when the failure determination means determines that the valve opening / closing timing variable mechanism has failed, the first flow rate calculation means based on the detected engine temperature and the estimated compression ratio. The flow rate of the fuel to be injected from the second injector is calculated .

  In the internal combustion engine start control apparatus according to claim 2, the first injector includes an injector that directly injects the various fuels into the combustion chamber, and the second injector is provided at an intake port in front of the combustion chamber. The injector is configured to include an injector for injecting the alcohol fuel.

  In the internal combustion engine start control device according to claim 3, the flow rate calculation means calculates the flow rate of fuel to be injected from the second injector to zero when the detected engine temperature is lower than a predetermined value. On the other hand, when the detected engine temperature is equal to or higher than a predetermined value, the flow rate of the fuel to be injected from the second injector is calculated so as to increase as the detected engine temperature increases.

  In the start control device for an internal combustion engine according to claim 4, the flow rate calculation means is configured to start with the various fuels when the failure determination means determines that the valve opening / closing timing variable mechanism has not failed. The valve opening / closing timing variable mechanism is operated so as to obtain a corresponding compression ratio, and the flow rate of fuel to be injected from the first injector is increased while the flow rate of fuel to be injected from the second injector is decreased. Thus, it was constituted so as to calculate.

In the start control device for an internal combustion engine according to claim 1, when the internal combustion engine is started, the engine temperature of the internal combustion engine is detected, it is determined whether or not the variable valve opening / closing timing mechanism has failed, and is detected. Based on the engine temperature and the failure determination result, the flow rate of the fuel to be injected is calculated from the first injector capable of injecting various fuels including alcohol and the second injector capable of injecting the alcohol fuel, Thus, since the fuel injection of the first and second injectors at the start of the internal combustion engine is controlled, for example, when it is determined that the valve opening / closing timing variable mechanism has not failed, the fuel is injected based on the engine temperature. The flow rate can be calculated, and therefore the first and second injectors that can inject various fuels and alcohol fuels with higher octane numbers and variable valve opening / closing timing In an internal combustion engine having a structure capable of improving the startability at engine temperature is low cold. Further, when it is determined that the valve opening / closing timing variable mechanism has failed, the flow rate of fuel to be injected from the first and second injectors is calculated based on the detected engine temperature and the estimated compression ratio. Therefore, even when it is determined that the valve opening / closing timing variable mechanism has failed, the internal combustion engine can be reliably started and knocking at the time of starting can be suppressed.

  In the start control device for an internal combustion engine according to claim 2, the first injector includes an injector that directly injects various fuels into the combustion chamber, and the second injector injects alcohol fuel into the intake port in front of the combustion chamber. In addition to the effects described above, the first injector is an injector that directly injects various fuels into the combustion chamber, so that abnormal combustion can be avoided by the latent heat of gasoline of the injected various fuels. When the injector is an injector that injects alcohol into the intake port, the accuracy and cost of components such as a pressure pump can be reduced, and the configuration can be simplified.

  In the internal combustion engine start control device according to claim 3, when the detected engine temperature is less than a predetermined value, the flow rate of fuel to be injected from the second injector is calculated to be zero, while the detected engine temperature Since the flow rate of fuel to be injected from the second injector is calculated so as to increase as the detected engine temperature increases, in addition to the above effects, the internal combustion engine has an engine temperature of While it is possible to start reliably when the temperature is low, knocking can be suppressed at high temperatures.

  In the start control device for an internal combustion engine according to claim 4, when it is determined that the valve opening / closing timing variable mechanism has not failed, the valve opening / closing timing variable mechanism is set so as to obtain a compression ratio corresponding to the starting with various fuels. In addition to the above-described effects, the internal combustion engine is operated so that the flow rate of fuel to be injected from the first injector is increased while the flow rate of fuel to be injected from the second injector is decreased. The engine can be reliably started when cold.

1 is a schematic diagram showing an overall control apparatus for an internal combustion engine according to an embodiment of the present invention. It is a block diagram which shows the operation | movement of ECU shown in FIG. 1 functionally. Fig. 2 is a flowchart showing more specifically the operation of the ECU shown in Fig. 1. 3 is an explanatory diagram showing the characteristics of the high RON injection ratio coefficient used in the processing of the flow chart. 3 is an explanatory diagram showing the characteristics of another high RON injection ratio coefficient used in the processing of the flow chart of FIG. 3 is an explanatory diagram for explaining the effect of the processing of the flow chart. Similarly, it is explanatory drawing explaining the effect by the process of the flowchart of FIG.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment for carrying out an internal combustion engine control apparatus according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing an overall control apparatus for an internal combustion engine according to an embodiment of the present invention.

  In FIG. 1, reference numeral 10 denotes a four-cylinder (cylinder) four-cycle internal combustion engine (only one cylinder is shown; hereinafter referred to as “engine”) mounted on a vehicle (not shown). In the engine 10, intake air drawn from an air cleaner (not shown) flows through the intake pipe 12, the flow rate is adjusted by the throttle valve 14, and flows through the intake manifold 16, for example, two intake valves (only one is shown) 20. Flows into the combustion chamber 22 when the valve is opened (opened).

  The throttle valve 14 is mechanically disconnected from the accelerator pedal 24 disposed on the vehicle driver's seat floor, and the opening and closing of the throttle valve 14 is controlled by a DBW (Drive By Wire) mechanism 26. That is, the throttle valve 14 is connected to an actuator (electric motor) 26a and is opened and closed by being driven by the actuator 26a.

  A first injector (fuel injection valve) 30 is disposed at a position facing the combustion chamber 22, and a second injector (fuel injection valve) 32 is disposed in the intake port 16 a in front of the intake valve 20.

  Various fuels stored in the main fuel tank 34 are pumped to the first injector 30 by a main fuel pump 34 a disposed inside the tank, and are pumped through the fuel supply pipe 36. The first injector 30 directly injects the various fuels fed under pressure into the combustion chamber 22. Hereinafter, the first injector 30 is also referred to as a “direct injection injector”.

  As the multi-fuel, it is planned to use a fuel having a relatively low alcohol concentration, such as a mixed fuel of gasoline and ethanol (ethyl alcohol), specifically, a mixed fuel (E10) of 90% gasoline and 10% ethanol.

  On the other hand, the various fuels stored in the main fuel tank 34 are pumped up by the sub fuel pump 34b and sent to the gas-liquid separator 42 through the pipe 40, where they are heated and cooled to be separated into alcohol components and other components.・ Extracted.

  The separated alcohol component is stored in the sub fuel tank 44 as alcohol fuel having a certain range of alcohol concentration, and the other components are returned to the main fuel tank 34 via the pipe 46.

  The alcohol fuel stored in the sub fuel tank 44 is pumped up by a fuel pump 44 a disposed inside the tank, and is pumped to the second injector 32 through the fuel supply pipe 50. In other words, alcohol fuel having a high octane number (high RON) is pumped to the second injector 32 compared to the various fuels pumped to the first injector 30.

  The second injector 32 injects the pumped alcohol fuel into the intake port 16a. Hereinafter, the second injector 32 is also referred to as a “port injector”. The injected alcohol fuel flows into the combustion chamber 22 when the intake valve 20 is opened.

  The direct injection injector 30 or the port injector 32 is electrically connected to an ECU (Electronic Control Unit) 54 through a driver (drive circuit; shown in FIG. 2) 52 and indicates a valve opening (opening) time from the ECU 54. When the drive signal is supplied through the driver 52, the valve is opened, and fuel corresponding to the valve opening time is injected into the combustion chamber 22 or the intake port 16a. The injected fuel is mixed with the inflowing air to generate an air-fuel mixture.

  A spark plug 56 is disposed in the combustion chamber 22. The spark plug 56 is connected to an ignition device 60 such as an igniter. When an ignition signal is supplied from the ECU 54 via the driver 52, the ignition device 60 generates a spark discharge between the electrodes of the spark plug 56. The air-fuel mixture is ignited and combusted thereby, and drives the piston 62 slidably accommodated in the combustion chamber 22 downward.

  Inside the cylinder block 64 in which the combustion chamber 22 is formed, a crankshaft (not shown) that is connected to the piston 62 and converts the vertical motion of the piston 62 into rotational motion is accommodated.

  Exhaust gas (exhaust gas) generated by the combustion flows from the exhaust manifold 74 to the exhaust pipe 76 through the exhaust port 72 when two exhaust valves (only one is shown) 70 are opened. The exhaust pipe 76 is provided with a catalyst device (not shown). Exhaust gas is discharged to the atmosphere outside the engine after removing harmful components such as HC, CO, and NOx by the catalyst device.

  The cylinder head 64 a is provided with a valve opening / closing timing variable mechanism (hereinafter referred to as “VTC”) 80. The VTC 80 is a hydraulic motor that can change the timing for opening and closing the combustion chamber of the intake valve, which is defined as the phase angle of the camshaft with respect to the crankshaft by driving the camshaft via hydraulic pressure. In addition to the VTC 80, a mechanism capable of changing the opening / closing phase angle and the lift amount of the intake cam 80b according to a plurality of cams (cams) may be provided.

  The output of the engine 10 is sent to the automatic transmission, where it is shifted and transmitted to the drive wheels, but the illustration of the automatic transmission and the like is omitted.

  A crank angle sensor 82 composed of a pulsar and a magnetic pickup is disposed in the vicinity of the camshaft of the engine 10, and a cylinder discrimination signal and a TDC signal indicating a TDC (top dead center) of each cylinder or a crank angle in the vicinity thereof, A CRK signal obtained by subdividing the TDC signal is output.

  An air flow meter 84 having a temperature detection element is disposed in the vicinity of the air cleaner, and outputs a signal corresponding to the amount of air (intake air) Q taken from the air cleaner and the intake air temperature TA.

  A MAP sensor 86 is disposed downstream of the throttle valve 14 in the intake pipe 12 to output a signal indicating the intake pipe pressure PBA in absolute pressure, and a throttle opening sensor 90 is disposed in the DBW mechanism 26. A signal corresponding to the position (throttle opening TH) is output.

  A water temperature sensor 92 is disposed in a cooling water passage (not shown) formed in the crankcase 64a of the engine 10 and outputs a signal corresponding to the engine cooling water temperature (engine temperature) TW. 94 is arranged to output a signal corresponding to vibration generated in the engine 10 due to knocking.

  In the exhaust system, an A / F sensor (wide area air-fuel ratio sensor) 96 is arranged upstream of the catalyst device, and in a wide range from the stoichiometric air-fuel ratio to rich or lean, in other words, the actual air concentration. A signal indicating the fuel ratio KACT is output.

Main fuel tank 34 and the gas-liquid separator 4 2 a wide fuel to the conduit 40 through the conduit 40 is disposed alcohol sensor 100 to be connected, a wide fuel stored in the main fuel tank 34 and more specifically In addition to outputting a signal indicating the alcohol concentration, a level sensor 102 is disposed in the sub fuel tank 44, and the level (liquid level height) of the alcohol fuel stored in the sub fuel tank 44, in other words, the remaining amount of alcohol fuel. A signal indicating is output.

  An accelerator opening sensor 104 is provided in the vicinity of the accelerator pedal 24, and outputs a signal corresponding to the accelerator opening AP indicating the amount by which the driver depresses the accelerator pedal. A vehicle speed sensor 106 is provided in the vicinity of a drive shaft (not shown), and outputs a pulse signal per predetermined angular rotation of the drive shaft.

  The output of the sensor group described above is input to the ECU 54. The ECU 54 includes a microcomputer and includes a CPU, a ROM, a RAM, an I / F, and the like. The ECU 54 measures (detects) the engine speed NE and the vehicle speed V by measuring the time interval between the output of the crank angle sensor 82 (CRK signal) and the output of the vehicle speed sensor 106 among the input signals.

  FIG. 2 is a block diagram functionally showing the operation of the ECU 54.

  In the ECU 54, the CPU 54a searches for an appropriate characteristic (map) from the engine speed NE and the engine load in the calculation unit 54a1 based on the sensor output input via the I / F 54b, and the fuel injection amount TOUT to be supplied to the engine 10 Is calculated.

  That is, the CPU 54a calculates the basic fuel injection amount TIM in accordance with the engine speed NE and the engine load, and in the air / fuel ratio feedback control for controlling the detected air / fuel ratio KACT to the target air / fuel ratio KCMD, The fuel injection amount is calculated by calculating the fuel ratio by correcting the basic fuel injection amount by calculating the fuel ratio correction coefficient (air-fuel ratio feedback correction coefficient) KAF and further calculating other correction coefficients such as the alcohol concentration correction coefficient (alcohol concentration learning value) KREFBS. TOUT is calculated.

The CPU 54a drives the direct injection injector 30 based on the calculated fuel injection amount TOUT. The alcohol concentration correction coefficient KREFBS is learned using the air-fuel ratio correction coefficient KAF, and the alcohol concentration is learned.

Incidentally, since the alcohol sensor 100 is provided in this embodiment, without using any alcohol concentration correction coefficient K REFBS described above, it may be calculated fuel injection amount TOUT from the output of the alcohol sensor 100 .

  The CPU 54a performs fuel injection control different from the above when the engine 10 is started, which will be described later.

  Further, the CPU 54a calculates (sets) the opening / closing timing of the intake valve 20 in the target phase calculation unit 54a2, calculates (sets) the target phase angle of the intake cam 80b of the VTC 80 corresponding to the opening / closing timing, and sets the target phase angle and The ignition timing calculation unit 54a3 calculates the ignition timing IG to be supplied to the engine 10 according to the engine speed NE and the engine load, and based on the ignition timing IG, the ignition timing is calculated via the ignition device 60. Ignition by the plug 56 is controlled.

The CPU 54a further calculates the target throttle opening THD in the throttle opening calculation unit 54a4. First, the CPU 54a calculates the required torque PCMD as follows.
PCMD = k · PSE / NE
The required output of the engine 10 obtained by searching a preset characteristic (map) from the above: k: constant, PSE: accelerator opening AP and engine speed NE is shown.

Next, the CPU 54a determines the target throttle opening THD so as to be the calculated required torque PCMD, and drives the actuator 26a of the DBW mechanism 26 so as to be the determined target throttle opening THD.

  FIG. 3 is a flowchart showing the operation of the ECU 54 limited to the starting of the engine 10. The illustrated program is executed at a predetermined crank angle near the TDC of each cylinder.

  In the following, it is determined in S10 whether or not the VTC (Valve Opening and Closing Timing Variable Mechanism) 80 has failed. This is determined by determining whether the actuator of the VTC 80 can be operated in a routine (not shown).

  When the result in S10 is negative, the program proceeds to S12, and the optimum VTC angle (optimum effective compression ratio) is adjusted. That is, the VTC 80 is operated (the operation is controlled) so that the opening / closing timing of the intake valve 20 obtained by driving the intake cam 80b with the actuator becomes an optimum effective compression ratio according to the start of the engine 10 with various fuels.

  Next, in S14, the high RON injection ratio coefficient Kcr is set to zero. FIG. 4 shows the characteristics of the high RON injection ratio coefficient Kcr. As shown in the figure, the high RON injection ratio Kcr is set to zero when the effective compression ratio is low to medium, and is set to increase as the effective compression ratio increases from medium to high.

  On the other hand, when the result in S10 is affirmative, the program proceeds to S16, in which the intake valve 20 is opened and closed, the intake air temperature TA detected from the temperature detection element of the air flow meter 84, the external air pressure (sensor not shown in FIG. 1 and the like), and the water temperature sensor. The intake air amount in the combustion chamber 22 is calculated from the engine coolant temperature (engine temperature) TW detected from 92, and the effective compression ratio is estimated (in other words, the estimated value of the effective compression ratio is calculated).

  Next, in S18, the characteristic shown in FIG. 4 is searched from the effective compression ratio estimated in S16 to calculate the high RON injection ratio coefficient Kcr.

  Next, in S20, another high RON injection ratio coefficient Ktw is calculated based on the detected engine coolant temperature TW. These coefficients Kcr and Ktw are coefficients indicating the ratio of high RON fuel injection to low RON fuel.

  FIG. 5 shows the characteristics of the high RON injection ratio coefficient Ktw. As shown in the figure, the high RON injection ratio Ktw is set to zero when the engine cooling water temperature TW is low to normal temperature, and is set to increase as the engine cooling water temperature TW exceeds normal temperature and increases to high temperature.

  Next, in S22, the required fuel flow rate Ggaso at start-up is calculated.

  That is, as in the case of using ordinary gasoline as fuel, the atmospheric pressure detected from the atmospheric pressure sensor (not shown in FIG. 1 and the like), the intake air temperature TA detected from the temperature detection element of the air flow meter 84, and the water temperature sensor 92 are detected. Based on the engine coolant temperature TW, etc., the optimal fuel flow rate required for starting the engine 10 and also in terms of emissions is calculated as Ggaso.

  As a result, the total amount of fuel required at the time of starting is determined, so that the fuel and fuel injection amount TOUT to be supplied to the engine 10 is calculated by adjusting the injection ratio of alcohol and gasoline so as to match the total amount of fuel.

  Next, the process proceeds to S24, where the low RON flow rate G1 is calculated from the illustrated formula, and the process proceeds to S26, where the high RON flow rate G2 is calculated from the illustrated formula. The low RON flow rate G1 means the flow rate of the low RON multi-fuel to be injected from the direct injection injector 30, and the high RON flow rate G2 means the flow rate of the high RON alcohol fuel to be injected from the port injector 32.

  In the equations of S24 and S26, Qgaso: gasoline lower heating value, Q1: low RON lower heating value, and Q2: higher RON lower heating value. The flow rates G1 and G2 mean the amount of fuel to be injected per cycle (stroke) of one cylinder.

  As described above, in S24 and S26, the flow rate of the fuel to be injected from the first and second injectors based on the detected engine coolant temperature TW and the determination result of whether or not the VTC 80 has failed according to the equation shown in the figure. Is calculated.

  More specifically, as is apparent from the equation shown in the drawing, when the detected engine coolant temperature TW is lower than a predetermined value (set to near room temperature as shown in FIG. 5), the fuel to be injected from the port injector 32 While the flow rate is calculated as zero, the flow rate of the fuel to be injected from the port injector 32 is calculated so as to increase as the engine coolant temperature TW increases when the flow rate is equal to or greater than a predetermined value.

  Further, when it is determined that the VTC 80 has not failed, the VTC 80 is operated so as to have a compression ratio corresponding to the start with various fuels, and the flow rate of fuel to be injected from the direct injector 30 is increased. Calculation is performed so that the flow rate of the fuel to be injected from the injector 32 decreases.

  On the other hand, when it is determined that the VTC 80 has failed, the flow rate of fuel to be injected from the direct injection injector 30 and the port injector 32 is calculated based on the detected engine coolant temperature TW and the compression ratio estimated in S16. To do.

  Next, in S28, the fuel injection and the fuel injection time to be injected from the direct injection 30 and / or the port injector 32 are controlled so that the calculated low RON flow rate G1 and high RON flow rate G2 are obtained.

  6 and 7 are explanatory views showing engine start according to this embodiment.

  In this embodiment, when starting the engine 10 in the cold machine (low temperature), by injecting low RON various fuels mainly composed of gasoline, as shown in FIG. The engine speed can be increased to the idling speed, and the engine 10 including the first and second injectors and the VTC 80 can be reliably started, and deterioration of emissions can be suppressed.

  Further, as shown in FIG. 7, if only the low RON fuel is started when the effective compression ratio is high, knocking may occur at a low engine speed, but the engine coolant temperature TW detected as described above. Is calculated to increase the flow rate of fuel to be injected from the port injector, the knocking can be effectively suppressed.

As described above, in this embodiment, the first injector (direct injection injector) 30 capable of injecting various fuels containing alcohol, and the second injector (port) capable of injecting alcohol fuel having an octane number higher than that of the various fuels. An injector) 32, and a valve opening / closing timing variable mechanism (VTC) 80 capable of changing the opening / closing timing of the intake valve 20 that opens and closes the combustion chamber 22, and fuel injected from at least one of the first and second injectors When the internal combustion engine is started in the start control device of the internal combustion engine (engine) 10 that generates an output by igniting and burning the air-fuel mixture obtained by mixing the intake air with the intake air, the engine temperature ( Engine temperature detection means (ECU 54, water temperature sensor 92) for detecting engine cooling water temperature TW, and the valve opening / closing timing variable mechanism A flow rate of fuel to be injected from the first and second injectors based on failure determination means (ECU 54, S10) for determining whether or not there is a failure, and the detected engine temperature and the determination result of the failure determination means And a fuel injection control means for controlling the fuel injection of the first and second injectors when the internal combustion engine is started so as to obtain the calculated fuel flow rate. (ECU 54, S28), and the flow rate calculating means determines that the detected engine temperature and the estimated compression ratio when the failure determining means determines that the valve opening / closing timing variable mechanism has failed. the first on the basis to calculate the flow rate of fuel to be injected from the second injector (S16, S24, S26) Owing to this configuration, VT When it is determined that the engine 80 has not failed, the flow rate of the fuel can be calculated based on the engine coolant temperature TW. Therefore, the first and second fuels that can inject various types of fuel and alcohol fuel having a higher octane number can be injected. In the engine 10 including the injector and the VTC 80, it is possible to improve the startability when the engine is cold. Further, when it is determined that the VTC 80 is malfunctioning, the flow rate of the fuel to be injected from the first and second injectors 30 and 32 is calculated based on the detected engine temperature and the estimated compression ratio. Even when it is determined that the VTC 80 has failed, the engine 10 can be reliably started and knocking at the time of starting can be suppressed.

  The first injector 30 is an injector that directly injects the various fuels into the combustion chamber 22, and the second injector 32 is an injector that injects the alcohol fuel into the intake port 16a in front of the combustion chamber. Since the first injector 30 is an injector that directly injects various fuels mainly composed of gasoline into the combustion chamber, the abnormal combustion can be avoided by the latent heat of gasoline of the injected various fuels. In addition, since the second injector 32 is an injector that injects alcohol into the intake port 16a, the accuracy and cost of components such as a pressure pump can be reduced, and the configuration can be simplified.

  The flow rate calculating means calculates the flow rate of fuel to be injected from the second injector to zero when the detected engine temperature is less than a predetermined value, while the detected engine temperature is equal to or higher than a predetermined value. At this time, since the flow rate of the fuel to be injected from the second injector is calculated so as to increase as the detected engine temperature increases (S26), in addition to the above effects, the engine 10 has an engine temperature of While it is possible to start reliably when the temperature is low, knocking can be suppressed at high temperatures.

  In addition, the flow rate calculation means is configured such that when the failure determination means determines that the valve opening / closing timing variable mechanism (VTC) 80 has not failed, the valve ratio is adjusted so that the compression ratio corresponds to the start with the various fuels. The open / close timing variable mechanism is operated (S12), and the flow rate of fuel to be injected from the first injector is increased while the flow rate of fuel to be injected from the second injector is decreased (S24, S24). 26) In addition to the effects described above, the engine 10 can be reliably started when cold.

  In the above description, the main fuel tank 34 stores various fuels including alcohol fuel, and the sub fuel tank 44 stores alcohol fuel. However, the main fuel tank 34 stores gasoline fuel and the sub fuel tank 44 stores alcohol fuel. You may do it.

  DESCRIPTION OF SYMBOLS 10 Internal combustion engine (engine), 14 Throttle valve, 20 Intake valve, 22 Combustion chamber, 26 DBW mechanism, 30 1st (direct injection) injector, 32 2nd (port) injector, 34 Main fuel tank, 42 Gas-liquid separator , 44 Sub fuel tank, 54 ECU (electronic control unit), 56 Spark plug (ignition means), 60 Ignition device (ignition means), 80 VTC (valve opening / closing timing variable mechanism), 82 Crank angle sensor, 84 Air flow meter, 86 MAP sensor, 90 throttle opening sensor, 96 A / F sensor, 100 alcohol sensor, 102 level sensor, 104 accelerator opening sensor

Claims (4)

A variable valve opening / closing timing capable of changing the opening / closing timing of an intake valve for opening / closing a combustion chamber, a first injector capable of injecting various fuels including alcohol, a second injector capable of injecting alcohol fuel having an octane number higher than that of the various fuels A starting control device for an internal combustion engine that generates an output by igniting and burning an air-fuel mixture obtained by mixing fuel injected from at least one of the first and second injectors with intake air in a combustion chamber Engine temperature detecting means for detecting the engine temperature of the internal combustion engine when starting the internal combustion engine, failure determining means for determining whether or not the valve opening / closing timing variable mechanism has failed, and the detected engine temperature And flow rate calculation means for calculating the flow rate of fuel to be injected from the first and second injectors based on the determination result of the failure determination means The first time of starting of the internal combustion engine so that the flow rate of the calculated fuel, second Rutotomoni a fuel injection control means for controlling the fuel injection of the injector, the flow rate calculating means, the failure When it is determined by the determination means that the valve opening / closing timing variable mechanism has failed, the flow rate of fuel to be injected from the first and second injectors is calculated based on the detected engine temperature and the estimated compression ratio. A start control device for an internal combustion engine.   The first injector is an injector that directly injects the various fuels into the combustion chamber, and the second injector is an injector that injects the alcohol fuel into an intake port in front of the combustion chamber. The start control device for an internal combustion engine according to claim 1.   When the detected engine temperature is less than a predetermined value, the flow rate calculation means calculates the flow rate of fuel to be injected from the second injector to zero, while when the detected engine temperature is equal to or higher than a predetermined value, 3. The start control device for an internal combustion engine according to claim 1, wherein the flow rate of the fuel to be injected from the second injector is calculated so as to increase as the detected engine temperature increases.   The flow rate calculation means operates the valve opening / closing timing variable mechanism so that the compression ratio according to the start with the various fuels is obtained when the failure determination means determines that the valve opening / closing timing variable mechanism has not failed. And calculating the flow rate of the fuel to be injected from the second injector while decreasing the flow rate of the fuel to be injected from the first injector. An internal combustion engine start control device according to claim 1.

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