JP2011144767A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately start an engine which can respond to a variety of sorts of fuel. <P>SOLUTION: A control device includes: a compression ratio variable mechanism 96 which can vary a compression ratio; a heat generating means 94 heating the inside of a combustion chamber 20; a fuel property measuring device measuring ignition performance of fuel; and an operation control device controlling operation of the compression ratio variable mechanism 96 and operation of the heat generating means 94 based on the ignition performance of the fuel measured by the fuel property measuring device, in start of an internal combustion engine. The operation of the compression ratio variable mechanism is controlled to make the compression ratio higher as the ignition performance of the fuel gets lower, and the operation of the heat generating means is controlled to make a heating time longer as the ignition performance of the fuel gets lower. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine for starting control of a compression ignition type internal combustion engine.

  Patent Document 1 discloses a control device for a diesel engine provided with a glow plug protruding into a combustion chamber. When starting a diesel engine, this device measures the time until the fuel first burns, and estimates the cetane number of the fuel based on this time. The larger the cetane number of the fuel, the shorter the energization duration time of the glow plug.

  On the other hand, each of Patent Document 2 and Patent Document 3 discloses a spark ignition internal combustion engine provided with a variable compression ratio mechanism capable of changing a mechanical compression ratio.

JP 2008-261236 A JP 2007-321589 A JP 2007-303423 A JP 2008-286531 A

  In recent years, an attempt has been made to put into practical use an internal combustion engine that can handle various fuels such as light oil fuel, gasoline fuel, and alcohol fuel. However, since the ignitability of alcohol fuel is generally inferior to that of light oil fuel or gasoline fuel, the glow plug energization time is determined based on the cetane number of the fuel as in the device of Patent Document 1 above. It is not easy to appropriately improve the startability of such an internal combustion engine only by making it variable.

  Therefore, the present invention has been made in view of such a point, and an object thereof is to appropriately start an internal combustion engine capable of handling various fuels.

  The present invention provides a control device for a compression ignition type internal combustion engine. An internal combustion engine control apparatus according to the present invention includes a compression ratio variable mechanism capable of changing a compression ratio, a heat generating means for heating a combustion chamber, a fuel property measuring device for measuring the ignitability of fuel, and an internal combustion engine And an operation control device for controlling the operation of the variable compression ratio mechanism and the operation of the heat generating means based on the ignitability of the fuel measured by the fuel property measuring device at the time of starting.

  Preferably, the operation control device controls the operation of the variable compression ratio mechanism so that the compression ratio increases as the ignitability of the fuel decreases, and the operation of the heating means increases so that the heating time increases as the ignitability of the fuel decreases. To control.

  The control device for an internal combustion engine according to the present invention further includes an air temperature detection device that detects the temperature outside the internal combustion engine, and the operation control device has a longer heating time as the air temperature detected by the air temperature detection device is lower. Thus, it is preferable to control the operation of the heat generating means.

  Furthermore, the control device for an internal combustion engine according to the present invention further includes an atmospheric pressure detection device for detecting atmospheric pressure, and the operation control device is configured such that the heating time becomes longer as the atmospheric pressure detected by the atmospheric pressure detection device is lower. It is preferable to control the operation of the heat generating means.

It is a mimetic diagram for explaining a schematic structure of an internal-combustion engine system to which a 1st embodiment concerning the present invention is applied. FIG. 2 is a diagram simply showing the flow of setting various values when the internal combustion engine of FIG. 1 is started. 2 is a time chart schematically showing an example of changes in key positions, glow indicator display, glow plug energization ON / OFF, and engine rotational speed at the start of the internal combustion engine of FIG. 1 on the same time axis. It is a figure showing the relationship between the cetane number and target compression ratio in 1st Embodiment. It is a figure showing the pre-glow time in 1st Embodiment by the relationship between a target compression ratio and external temperature. It is a figure showing the afterglow time in 1st Embodiment by the relationship between a target compression ratio and external temperature. It is the figure which represented simply the flow of the setting of the various values at the time of start-up of the internal combustion engine in 2nd Embodiment. It is a figure showing the relationship between atmospheric pressure and a correction coefficient in 2nd Embodiment.

  Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, a first embodiment according to the present invention will be described. FIG. 1 shows a schematic configuration of an internal combustion engine system to which the first embodiment is applied. However, the internal combustion engine 10 is a compression ignition type internal combustion engine.

  The combustion chamber 20 defined in the cylinder 16 by the cylinder head 12 and the piston 18 reciprocating in the cylinder 16 of the cylinder block 14 is provided with a fuel injection valve 22 so as to face the combustion chamber 20. The internal combustion engine 10 diffuses and burns a mixture of fuel and air injected and supplied from the fuel injection valve 22 by compression auto-ignition inside the combustion chamber 20, and reciprocates the piston 18 in the cylinder 16 to generate power. It is generated and is configured to rotate the crankshaft 24. Although only one cylinder is shown in FIG. 1, the internal combustion engine 10 is preferably configured as a multi-cylinder engine, and the internal combustion engine 10 of the present embodiment is configured as a four-cylinder engine, for example.

  An intake port 26 facing each combustion chamber 20 is opened and closed by an intake valve 28. The intake port 26 is connected to an intake manifold 30, and a surge tank 32 and an intake pipe 36 are sequentially connected to the upstream side of the intake manifold 30. The intake pipe 36 is connected to an air intake port via an air cleaner 38. A throttle valve 42 driven by an actuator 40 is provided between the surge tank 32 and the air cleaner 38. For example, each of the intake port 26, the intake manifold 30, and the intake pipe 36 defines a part of the intake passage 44.

  On the other hand, the exhaust port 46 facing each combustion chamber 20 is opened and closed by an exhaust valve 48. The exhaust port 46 is connected to an exhaust manifold 50, and an exhaust pipe 52 is connected to the exhaust manifold 50 on the downstream side. For example, each of the exhaust port 46, the exhaust manifold 50, and the exhaust pipe 52 defines a part of the exhaust passage 54. A catalytic converter 56 filled with an exhaust gas purification catalyst is provided in the middle of the exhaust passage 54.

  Further, an exhaust gas recirculation (EGR) device 58 is provided to guide part of the exhaust gas flowing through the exhaust passage 54 to the intake passage 44. The EGR device 58 includes an EGR pipe 62 that defines an EGR passage 60 that communicates the exhaust passage 54 and the intake passage 44, an EGR valve 64 that adjusts the communication state of the EGR passage 60, and exhaust gas that is recirculated (EGR gas). ) EGR cooler 66 for cooling. Here, one end on the upstream side of the EGR pipe 62 is connected to the exhaust manifold 50, and the other end on the downstream side thereof is connected to the intake manifold 30. The EGR valve 64 is provided on the downstream side of the EGR cooler 66, and its opening degree is adjusted by an actuator 68.

  Further, a turbine 72 including a turbine wheel 70 that is rotationally driven by exhaust gas is provided in the exhaust passage 54. Correspondingly, a compressor 78 including a compressor wheel 76 that is coaxially connected to the turbine wheel 70 via a rotating shaft 74 and is rotated by the rotational force of the turbine wheel 70 is provided in the intake passage 44. That is, the internal combustion engine 10 is provided with a turbocharger 80 that includes a turbine 72 that extracts exhaust energy and a compressor 78 that supercharges the internal combustion engine 10 by the exhaust energy extracted by the turbine 72. An intercooler 82 is provided downstream of the compressor 78 in order to cool the air compressed by the compressor 78. The turbocharger 80 is configured as a variable nozzle turbocharger including a plurality of variable nozzle vanes 84 at the turbine inlet. The operations of the plurality of vanes 84 are performed by a drive mechanism (not shown) whose operation is controlled by a control device C described later.

  The internal combustion engine 10 includes a fuel supply system 92 that pumps fuel from a fuel tank 86 to a common rail 90 by a pump 88 and supplies the fuel to a fuel injection valve 22 through the common rail 90. In the internal combustion engine 10, light oil is mainly used as fuel. However, in the internal combustion engine 10, liquid fuel other than light oil, for example, alcohol fuel or gasoline fuel can be used in addition to or instead of light oil.

  The combustion chamber 20 is provided with a glow plug 94 as heat generating means for heating the inside of the combustion chamber 20. The glow plug 94 is provided so as to protrude into the combustion chamber 20. The glow plug 94, which is a heat generating means, constitutes a heating device that enables heating of the combustion chamber 20 when the internal combustion engine is started, together with a part of a control device C that controls the operation thereof.

  On the other hand, the internal combustion engine 10 includes a compression ratio variable mechanism 96 that can change the compression ratio. The variable compression ratio mechanism 96 has the same configuration as the variable compression ratio mechanism disclosed in Patent Document 2 or Patent Document 3. Briefly, the variable compression ratio mechanism 96 is provided at a connecting portion between the crankcase attached to the lower part of the cylinder block 14 and the cylinder block 14, and changes the relative position of the crankcase and the cylinder block 14 in the cylinder axis direction. By doing so, the volume of the combustion chamber 20 when the piston 18 is located at the compression top dead center can be changed. The operation of the compression ratio variable mechanism 96 is controlled by a control device C described later. Such a variable compression ratio mechanism 96 is a variable compression ratio mechanism that can change the mechanical compression ratio of the internal combustion engine 10, but the opening timing and / or the closing timing of at least one of the intake and exhaust valves 28 and 48. It is possible to provide a variable compression ratio mechanism that makes the compression ratio substantially variable by making the variable variable.

  The crankshaft 24 can be given an initial rotation by a starting electric motor (starter motor) 98. The starter motor 98 is operated by moving the engine operation key from the OFF position to the Starter (ST) position via the ACC position and the IG position (engine start preparation position). Note that after being moved to the ST position, the key can be automatically moved to the IG position. Note that the control device C of the internal combustion engine 10 is configured so that the starter motor 98 is not operated when a glow indicator (not shown) that can be turned on when the glow plug 94 is operated is lit.

  The internal combustion engine 10 includes various sensors that electrically output signals for obtaining various values in a control device C including a control circuit. Here, some of them will be specifically described. An air flow meter 100 for detecting the amount of intake air is provided in the intake passage 44. Further, an intake air temperature sensor 102 for detecting the temperature of the intake air is provided. An intake pressure sensor 104 for detecting intake pressure, that is, supercharging pressure, is provided in the intake passage 44. Further, an accelerator opening sensor 108 for detecting a position corresponding to the depression amount of the accelerator pedal 106 operated by the driver, that is, an accelerator opening is provided. A crank position sensor 110 for detecting a crank rotation signal of the crankshaft 24 is attached. Here, the crank position sensor 110 is also used as an engine rotation speed sensor for detecting the engine rotation speed. Further, the fuel supply system 92 is provided with a fuel temperature sensor 112 for detecting the temperature of the fuel. In addition, a fuel property sensor 114 for detecting the property of the fuel is provided. The fuel property sensor 114 is provided for detecting (measuring) the cetane number as the property of fuel related to ignition (ignition property of fuel). Specifically, the fuel property sensor 114 is configured as a sensor capable of detecting the light transmittance and refractive index of the fuel. An example of such a fuel property sensor is disclosed in Patent Document 4. There is a correlation between the cetane number of the fuel and the refractive index of the fuel. However, the fuel property sensor 114 is not limited to having such a configuration, and may have other configurations. Further, the fuel property sensor 114 can be provided in the fuel tank 86 and the fuel supply passage 116. Furthermore, a temperature sensor (outside temperature sensor) 118 for detecting the temperature outside the internal combustion engine, that is, the outside temperature is provided. An atmospheric pressure sensor 120 for detecting atmospheric pressure is provided.

  The control device C is composed of a microcomputer including a CPU, ROM, RAM, A / D converter, input interface, output interface, and the like. The aforementioned various sensors are electrically connected to the input interface. Based on the output signals (detection signals) from these various sensors, the control device C performs an operation or the like according to a preset program so that the internal combustion engine 10 can be smoothly operated or operated. An operation signal (drive signal) is electrically output. Thus, the operation of the fuel injection valve 22, the opening degrees of the throttle valve 42 and the EGR valve 64, the operation of the pump 88, the operation of the glow plug 94, the operation of the variable compression ratio mechanism 96, and the like are controlled. In order to control the operation of the variable compression ratio mechanism 96, the control device C controls the operation of a drive motor provided in the variable compression mechanism 96.

  Here, the fuel property measuring device includes the fuel property sensor 114 and a part of the control device C. The air temperature detection device that detects the temperature outside the internal combustion engine includes an outside air temperature sensor 118 and a part of the control device C. Furthermore, the atmospheric pressure detection device that detects the atmospheric pressure includes the atmospheric pressure sensor 120 and a part of the control device C. The operation control device includes a part of the control device C.

  In the internal combustion engine 10 having the above configuration, the intake air amount obtained based on the output signal from the air flow meter 100, the engine rotational speed obtained based on the output signal from the crank position sensor 110, that is, the engine load and the engine rotational speed. Usually, the fuel injection amount (fuel amount) and the fuel injection timing are set based on the engine operation state represented by Based on the fuel injection amount and the fuel injection timing, fuel is injected from the fuel injection valve 22.

  And the internal combustion engine 10 provided with the said structure is comprised so that it may start appropriately. The start control will be described below. Hereinafter, a specific example of the control of the operation of the glow plug 94 and the operation of the compression ratio variable mechanism 96 based on the ignitability of the fuel when starting the internal combustion engine 10 will be described.

  When the key is moved from the OFF position to the ACC position by the driver, or when the key is moved to the IG position, the control device C is activated and measures the property of fuel related to ignition, that is, the ignitability (step S201). In the example shown in FIG. 3, at t1, the ignitability of the fuel is obtained and the following various values are set. Measurement or detection of the ignitability of the fuel is executed based on an output signal from the fuel property sensor 114. Here, the cetane number, which is an index indicating the difficulty of self-ignition of the fuel, is measured as an index indicating the ignitability of the fuel.

  Based on the measured cetane number, the target compression ratio ε is obtained and set by searching the data as shown in FIG. 4 (step S203). The data represents the relationship between the cetane number and the target compression ratio ε, and has a relationship that the target compression ratio ε increases as the cetane number decreases (the fuel is less likely to self-ignite). However, the data in FIG. 4 is determined such that the increase rate of the target compression ratio ε increases as the cetane number decreases. In FIG. 4, the cetane number of a fuel consisting only of ethanol, a fuel consisting of gasoline, a light oil-based fuel containing ethanol (low cetane light oil), and a fuel consisting only of light oil is shown as an example. Note that the relationship between the cetane number and the target compression ratio ε in FIG. 4 is an example, and may be determined to have a proportional relationship, for example.

  When the target compression ratio ε is determined, the pre-glow time t2 is obtained and set (step S205). The pre-glow time is a kind of heating time for heating the inside of the combustion chamber 20, that is, a time (glow time) in which the glow plug 94 is operated (energized) (glow time). Is the time to activate (pre-glow). That is, during the pre-glow time t2, the glow plug 94 is energized to heat the inside of the fuel chamber 20, but the engine start with fuel injection is substantially prohibited. Here, the pre-glow time t2 is obtained by searching the data shown in FIG. 5 based on the target compression ratio ε and the outside air temperature Ta detected based on the output signal from the outside air temperature sensor 118. Is set. However, the unit of the pre-glow time t2 in FIG. 5 is seconds. The data in FIG. 5 is determined such that the higher the target compression ratio ε, the longer the pre-glow time, in other words, the lower the cetane number of the fuel, the longer the pre-glow time t2. Further, the data of FIG. 5 is determined so that the pre-glow time t2 becomes longer as the outside air temperature Ta is lower. The pre-glow time t2 is a time equal to or greater than zero.

  Further, when the pre-glow time t2 is set, the afterglow time t3 is obtained and set (step S207). The afterglow time is a kind of heating time for heating the inside of the combustion chamber 20, that is, a time (glow time) in which the glow plug 94 is operated (energized), and after fuel injection is enabled (pre-glow time). This is a time period for which the glow plug 94 is continuously operated (after glowing) after t2 elapses. The afterglow at the afterglow time t3 continues to the preglow at the preglow time t2. During the afterglow time t3, the glow plug 94 is energized, but the internal combustion engine 10 can be started. Here, the afterglow time t3 is searched based on the obtained target compression ratio ε and the outside air temperature Ta detected based on the output signal from the outside air temperature sensor 118 as shown in FIG. That is what is sought and set. However, the unit of the afterglow time t3 in FIG. 6 is second. Note that the outside air temperature Ta for obtaining the afterglow time can be the outside air temperature Ta for obtaining the pre-glow time. The data shown in FIG. 6 is determined such that the higher the target compression ratio ε, the longer the afterglow time, in other words, the lower the cetane number of the fuel, the longer the afterglow time. Further, the data in FIG. 6 is determined so that the afterglow time becomes longer as the outside temperature Ta is lower. The afterglow time t3 is a time greater than or equal to zero.

  Setting of the target compression ratio ε and the glow time composed of the pre-glow time and the afterglow time based on the ignitability of the fuel is performed every time the internal combustion engine 10 is started. The internal combustion engine is started based on the target compression ratio ε and the glow time set based on the ignitability of the fuel. That is, when the internal combustion engine 10 is started at the request of the driver, the glow plug 94 is energized during the pre-glow time t2 and / or the afterglow time t3, and on the other hand, the compression ratio variable mechanism so that the target compression ratio ε is reached. The operation of 96 is controlled. When the pre-glow time t2 and the after-glow time t3 are zero, the glow plug 94 is not operated, and the operation of the compression ratio variable mechanism 96 is controlled so that the target compression ratio ε is reached. However, the operation of the compression ratio variable mechanism 96 is preferably performed quickly and as early as possible.

  Returning to FIG. 3, the description will be continued. When the driver moves the key to the IG position, the operation of the compression ratio variable mechanism 96 is controlled so that the target compression ratio ε is reached, and the glow plug 94 is energized during the pre-glow time t2 (the pre-glow is Done). That is, the start of the pre-glow is when the driver makes a start preparation request for the internal combustion engine 10 among the start requests for the internal combustion engine. In this case, the key is specifically moved to the IG position. is there. It should be noted that when the driver makes a start preparation request for the internal combustion engine 10, the case where the key is moved directly to the ST position via the IG position is included. When the glow plug 94 is energized, the glow indicator is turned on. When the pre-glow time t2 is zero, the internal combustion engine 10 can be started.

  As the pre-glow time t2 elapses, the starter motor 98 can be operated, and the glow indicator is turned off. In FIG. 3, immediately after that, the key is moved to the ST position, and the operation of the starter motor 98 is started. As a result, the internal combustion engine 10 is started and fuel injection from the fuel injection system 92 is started.

  When the after glow time t3 is not zero, the glow plug 94 is energized during the after glow time t3 after the pre-glow time t2. At this time, the glow indicator is kept off. Then, after the after glow time t3 has elapsed, the energization of the glow plug 94 is turned off. Thereby, the internal combustion engine 10 is appropriately warmed up, and when the internal combustion engine 10 is started, the engine rotation speed can be appropriately increased to the (target) idle rotation speed (see FIG. 3).

  When the key is moved to the OFF position without being moved to the ST position during or after the pre-glow or after glow, and when the key is further moved to the ACC position, IG position or ST position, Setting and operation control of the glow plug 94 and the compression ratio variable mechanism 96 are performed.

  Thus, the compression ratio ε and the glow time are set based on the ignitability of the fuel, and the internal combustion engine 10 is started based on these. Therefore, although the fluctuation range of the compression ratio is subject to mechanical restrictions (for example, the piston displacement is limited), the glow time is made variable in accordance with the properties of the fuel, so even if a fuel with poor ignitability is used. Thus, the internal combustion engine 10 can be appropriately started.

  For example, alcohol fuel is much inferior in terms of ignitability than light oil fuel, so when using alcohol fuel, simply increasing the glow time or increasing the compression ratio without operating the glow plug It is not easy to start the internal combustion engine 10 properly. Further, if the compression ratio is excessively increased, there is a possibility that fuel efficiency and emission may be deteriorated when light oil is used. However, as described above, the compression ratio ε and the glow time are set according to the properties of the fuel, and the operation of the glow plug and the compression ratio variable mechanism is controlled, so that various fuels such as alcohol fuel and light oil fuel can be used. When used, the internal combustion engine can be started properly.

  Furthermore, as described above, since the glow time is set based on the outside air temperature and the operation of the glow plug is controlled, it is possible to appropriately improve the cold startability of the internal combustion engine.

  In the above embodiment, the outside air temperature Ta is used to set the glow times t2 and t3, but the intake air temperature and / or the engine cooling water temperature can be used instead of or together with this.

  Next, a second embodiment according to the present invention will be described. The internal combustion engine system to which the second embodiment is applied has substantially the same configuration as the internal combustion engine system of the first embodiment. Therefore, below, the same code | symbol as the said component is attached | subjected to the component which is the same as the above-mentioned component, or corresponding, and those duplication description is abbreviate | omitted. The second embodiment differs from the first embodiment in the setting method of the pre-glow time t2 and the setting method of the after-glow time t3. Therefore, this point will be mainly described below. In the second embodiment, the same changes as those in the first embodiment can be applied, and the same effects can be obtained.

  FIG. 7 is a diagram simply showing the flow of setting various values when the internal combustion engine 10 of the second embodiment is started. Since steps S701 to S707 in FIG. 7 substantially correspond to the above-described steps S201 to S207, description thereof will be omitted.

  As described in the first embodiment, when the target compression ratio ε (step S703) and the glow times t2 ′ and t3 ′ (steps S705 and S707) are obtained based on the ignitability of the fuel (step S701), first, a large value is obtained. The atmospheric pressure is detected (step S709). However, these glow times t2 ′ and t3 ′ correspond to the glow times t2 and t3 in steps S205 and S207, respectively. The atmospheric pressure is detected based on an output signal from the atmospheric pressure sensor 120. However, the atmospheric pressure can be a pressure detected (including estimated) based on a signal output from the intake pressure sensor 104 when the internal combustion engine 10 is immediately stopped, and the next (current) internal combustion engine. It may be a value stored for 10 starts.

  Then, an atmospheric pressure correction coefficient k is obtained based on the atmospheric pressure (step S711). The atmospheric pressure correction coefficient k can be obtained by searching data as shown in FIG. 8 based on the atmospheric pressure. The data in FIG. 8 is set such that the atmospheric pressure correction coefficient k increases as the atmospheric pressure (absolute pressure) decreases.

  Then, the glow time t2 ′ is corrected using the atmospheric pressure correction coefficient k (step S713), and the glow time t3 ′ is corrected (step S715). Here, each of the obtained glow times t2 ′ and t3 ′ is multiplied by the atmospheric pressure correction coefficient k. Thus, the pre-glow time t2 (t2 ′ × k) and the afterglow time t3 (t3 ′ × k) are obtained and set.

  Thus, since the pre-glow time t2 and the afterglow time t3 are set based on the atmospheric pressure, the internal combustion engine can be appropriately started even at high altitudes where the atmospheric pressure is low.

  As mentioned above, although this invention was demonstrated based on two embodiment, the order of each step of the said FIG. 2 or FIG. 7 may differ. The order of steps S201 to S207 can be varied within a consistent range, and the order of steps S701 to S715 can be varied within a consistent range. Note that some steps can be omitted, and a plurality of steps can be combined. In the present invention, embodiments in which all of the above-described two embodiments and their modifications, or a combination of one or more portions are combined are also permitted in the present invention.

  Although the present invention has been described with a certain degree of specificity in both the above-described embodiments and modifications thereof, various modifications can be made to the present invention without departing from the spirit and scope of the invention described in the claims. It must be understood that changes are possible. That is, the present invention includes modifications and changes that fall within the scope and spirit of the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 20 Combustion chamber 22 Fuel injection valve 44 Intake passage 54 Exhaust passage 58 EGR device 80 Turbocharger 86 Fuel tank 88 Pump 92 Fuel supply system 94 Glow plug 96 Compression ratio variable mechanism 98 Starter motor 114 Fuel property sensor 118 Outside temperature sensor 120 atmospheric pressure sensor

Claims (4)

A control device for a compression ignition type internal combustion engine,
A variable compression ratio mechanism capable of changing the compression ratio;
Heating means for heating the combustion chamber;
A fuel property measuring device for measuring the ignitability of the fuel;
And an operation control device that controls the operation of the variable compression ratio mechanism and the operation of the heat generating means based on the ignitability of the fuel measured by the fuel property measuring device when the internal combustion engine is started. A control device for an internal combustion engine characterized by the above. The operation control device includes:
The operation of the variable compression ratio mechanism is controlled so that the compression ratio increases as the ignitability of the fuel decreases.
2. The control apparatus for an internal combustion engine according to claim 1, wherein the operation of the heat generating means is controlled so that the heating time becomes longer as the ignitability of the fuel is lower. An air temperature detecting device for detecting an air temperature outside the internal combustion engine;
3. The control of the internal combustion engine according to claim 1, wherein the operation control device controls the operation of the heat generating means so that the heating time becomes longer as the air temperature detected by the air temperature detection device is lower. apparatus. Further equipped with an atmospheric pressure detection device for detecting atmospheric pressure,
The said operation control apparatus controls the action | operation of the said heat generating means so that heating time becomes long, so that the atmospheric pressure detected by the said atmospheric pressure detection apparatus is low. Control device for internal combustion engine.

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