JP2007332938A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve fuel consumption while avoiding the attachment of fuel to the back of suction valve when starting an internal combustion engine. <P>SOLUTION: The controller of the internal combustion engine is provided with the valve gear (10) that can change at least either the opening/closing time or lift of a suction valve (203) for the suction of air into the combustion chamber (201) of the internal combustion engine (200), a temperature detection means (220) to detect the temperature of an internal combustion chamber, and further a control means (100) that controls the operation of the valve gear to change at least either one or the other according to the temperature detected when starting the internal combustion engine. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine having valve operating means capable of changing valve operating characteristics of an intake valve, such as VVT-i (Variable Valve Timing intelligent system: VVT-i).

  Various techniques have been proposed for improving the fuel consumption of an internal combustion engine by devising the opening / closing operation of the intake valve using this type of valve operating means. For example, a technique has been proposed in which the timing of closing the intake valve is made relatively early, such as so-called early closing. However, in the timing control of the opening / closing operation of the intake valve and the like in this way, if the fuel adheres to the back of the intake valve and forms a deposit, the actual intake air amount may change greatly.

  In order to cope with such a problem, for example, as disclosed in Patent Document 1 below, a technique has been proposed in which the lift amount of the intake valve is decreased to increase the flow rate of intake air and remove deposits. (See Patent Document 1).

JP 2005-16491 A

  However, the technique disclosed in Patent Document 1 described above may have the following problems. For example, when the flow rate of intake air is not yet developed as at the start of the internal combustion engine, the lift amount is reduced as in the technique disclosed in Patent Document 1, and the flow rate of intake air is increased by reducing the opening area. The moment of passing through the intake valve, when passing through the reduced opening, and before passing through the intake valve, the flow rate of the intake air in the intake pipe is not so fast. Therefore, at the time of such start-up, there is still a possibility that the fuel injected into the intake pipe does not ride on the intake flow and adheres to the back of the valve umbrella.

  The present invention has been made in view of, for example, the above-described problems. For example, a control device for an internal combustion engine that can improve fuel consumption while avoiding fuel from adhering to the umbrella of an intake valve when the internal combustion engine is started. It is an issue to provide.

  In order to solve the above problems, a control device for an internal combustion engine according to the present invention includes a valve operating means capable of changing at least one of an opening / closing timing and a lift amount of an intake valve for performing intake into the combustion chamber of the internal combustion engine, Temperature detecting means for detecting the temperature of the internal combustion engine; and control means for controlling the valve operating means so as to change at least one according to the detected temperature when the internal combustion engine is started. .

  According to this control device for an internal combustion engine, for example, the combustion chamber and the intake pipe of the internal combustion engine are predetermined by a valve operating means such as a drive mechanism for moving an intake valve in a VVT-i having a Camwire mechanism or an electromagnetically driven valve mechanism. At least one of the opening / closing timing and the lift amount of the intake valve communicating with the timing can be changed.

  For example, the temperature of the internal combustion engine is detected by detection means such as a temperature sensor provided in the intake pipe. Here, the “temperature of the internal combustion engine” is a quantitative value for directly or indirectly specifying the state of the fuel injected into the intake pipe or the combustion chamber (for example, how much it is evaporated). It is a comprehensive concept indicating a scale. Therefore, for example, the temperature of the engine cooling water or the temperature of the outer wall of the cylinder may be used. In practice, the detection output of an existing temperature sensor is preferably used, or a dedicated sensor may be provided.

  In general, when the flow rate of intake air is not yet developed, such as when starting an internal combustion engine, fuel adheres to the back of the intake valve umbrella even if it is closed early to improve fuel efficiency, as described above. There is a risk of doing. This tendency is particularly remarkable at the cold start. Here, “at the time of cold start” refers to a state in which it is assumed that the fuel is not sufficiently evaporated because the warm-up is still insufficient when the internal combustion engine is started. Thus, if the fuel is not sufficiently evaporated, the fuel that has not evaporated is more likely to adhere to the back of the intake valve umbrella.

  However, according to the present invention, when the internal combustion engine is started, for example, during cold start, the ECU is configured to change at least one of the opening / closing timing of the intake valve and the lift amount according to the detected temperature. The valve operating means is controlled by the control means. For example, the opening and closing timing of the intake valve is a slow closing Atkinson (Miller) cycle at cold start, and early closing after warm air, so that the compression ratio can be lowered to prevent the occurrence of knocking, The expansion ratio is increased to improve the thermal efficiency and the fuel efficiency is expected to be improved. At this time, if the valve is closed slowly and the lift amount is increased, the flow rate of the intake air is easily developed, so that the fuel can be prevented from adhering to the back of the intake valve.

  As a result, when starting the internal combustion engine, fuel efficiency is improved while avoiding fuel from adhering to the back of the intake valve umbrella.

  In one aspect of the control apparatus for an internal combustion engine according to the present invention, the control means closes the intake valve earlier than bottom dead center according to the detected temperature, or closes the bottom dead center. The valve operating means is controlled so as to be closed later.

  According to this aspect, depending on the detected temperature, the intake valve is closed early before bottom dead center or late closed after bottom dead center, so that the substantial compression ratio is kept small. The expansion ratio is made larger than the compression ratio. Here, “bottom dead center” means the time when the piston that reciprocates up and down in the combustion chamber reaches the lowest position in a narrow sense, but in a broad sense, at a position with a slight margin at the lowest position. It may mean the time to reach or the time when the compression ratio becomes maximum. Thus, since the internal combustion engine is operated in a so-called Atkinson (Miller) cycle, it is possible to prevent the occurrence of knocking and improve the thermal efficiency. At this time, from the viewpoint of keeping the substantial compression ratio small, “early closing” and “slow closing”, which have substantially the same effect, are properly used according to the detected temperature, so that the flow rate of the intake air can be developed. It is possible to avoid the adhesion of fuel by adjusting.

  In this aspect, at the time of starting, the control means sets the intake valve to the delayed closing when the detected temperature falls below a predetermined temperature threshold, and sets the intake valve to the early closing when the detected temperature does not fall below the predetermined temperature threshold. The valve operating means may be controlled.

  According to this aspect, it is determined whether to close the intake valve early or late according to the magnitude relationship between the temperature detected at the time of starting and the predetermined temperature threshold. Here, the “predetermined temperature threshold value” is a temperature that is determined in advance by experience, experiment, simulation, or the like as a temperature at which the fuel injected into the intake pipe is assumed to evaporate at a predetermined rate or more. 80 °. The “predetermined ratio” here does not necessarily have to be 100%. For example, if the fuel evaporates more than 80%, the amount adhering to the intake valve is determined as a value that does not cause a problem in practice. That's fine. In the case of a cold start where the temperature detected at the time of start is below a predetermined temperature threshold, the fuel is not sufficiently evaporated and may adhere to the intake valve, so the intake valve is closed late. As a result, the flow velocity of the intake air develops faster than when the valve is closed early, and the adhesion of fuel to the back of the intake valve umbrella can be avoided. On the other hand, when the detected temperature does not fall below the predetermined temperature threshold and the warm air is sufficient, the fuel is sufficiently evaporated and there is no possibility of adhering to the intake valve, so that the valve is closed early. As a result, compared to the case where the valve is closed late, the temperature in the combustion chamber is increased and combustion is improved.

  In another aspect of the control apparatus for an internal combustion engine according to the present invention, the control means controls the valve operating means so that the lift amount exceeds a predetermined lift amount threshold value at the time of starting.

  According to this aspect, the lift amount exceeds the predetermined lift amount threshold. Here, the “predetermined lift amount threshold value” is used to increase the flow rate of the intake air when passing through the intake valve by a predetermined amount only by reducing the lift amount, and to shake off the deposit adhering to the umbrella back of the intake valve. The required lift amount is a value determined in advance by experience, experiment, simulation, or the like. In the present aspect, the flow rate of the intake air can be increased over a wide range in the intake pipe by increasing the lift amount at least above this value and, by that amount, late closing or the like. Therefore, it is possible to avoid the fuel from getting on the intake flow with the increased flow velocity and the fuel from adhering to the back of the umbrella of the intake valve, thereby removing the adhering fuel.

  In another aspect of the control apparatus for an internal combustion engine according to the present invention, a throttle valve opening / closing provided in a flow path of an intake pipe communicating with the intake valve and opening / closing a throttle valve for restricting a flow rate of intake air flowing through the intake pipe And the control means is configured such that, when the detected temperature falls below a predetermined temperature threshold at the time of starting, the opening of the throttle valve is larger than the opening determined from the accelerator opening. The throttle valve opening / closing means is controlled.

  According to this aspect, when the detected temperature falls below the predetermined temperature threshold value at the time of starting, the opening degree of the throttle valve is larger than the opening degree determined from the accelerator opening degree, for example, is fully opened. Therefore, pump loss at the throttle valve can be reduced. Here, the “opening determined from the accelerator opening” is an accelerator opening calculated and determined by a control device such as an ECU based on the accelerator opening that the driver has depressed during normal driving. Even in this case, the flow rate of the intake air can be adjusted by closing the intake valve late or early. In particular, if the throttle valve is fully opened, the intake valve is closed slowly, and the lift amount is set to a value exceeding a predetermined lift amount threshold value, the flow of intake air becomes faster and the fuel adheres to the intake valve. It is possible to avoid or remove the adhered fuel.

  In another aspect of the control apparatus for an internal combustion engine according to the present invention, the valve operating means can further change at least one of an opening / closing timing and a lift amount of an exhaust valve for exhausting from the combustion chamber, When the detected temperature falls below the predetermined temperature threshold at the time of starting, the control means reduces the overlap amount in which the intake valve and the exhaust valve are both open compared to a case where the detected temperature is not lower than the predetermined temperature threshold. Thus, the valve operating means is controlled.

  According to this aspect, when the detected temperature is lower than the predetermined temperature threshold value at the time of start-up, for example, the opening time of the intake valve is delayed compared to the case where the detected temperature is not lower. As a result, the amount of overlap is reduced, and exhaust gas can be prevented from blowing back to the intake pipe. That is, deterioration of combustion can be avoided.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings as the best mode for carrying out the invention.

(1) Configuration First, the configuration of an internal combustion engine including the control device for an internal combustion engine according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of an internal combustion engine provided with the control device for an internal combustion engine according to the embodiment of the present invention.

  In FIG. 1, an internal combustion engine 200 includes a variable valve operating apparatus 10 that is an example of “valve moving means” according to the present invention, an intake pipe 206, and a temperature sensor 220 that is an example of “temperature detecting means” according to the present invention, The throttle valve drive motor 217, the combustion chamber 201, the exhaust pipe 210, the turbocharger (that is, the compressor 41 and the turbine 42), which are examples of the “throttle valve opening / closing means” according to the present invention, and the “control means” according to the present invention. The control apparatus 100 etc. which are an example are provided.

  The intake pipe 206 is controlled to communicate with the combustion chamber 201 by opening and closing the intake valve 203. That is, in the intake pipe 206, air sucked from the outside (that is, sucked air) and fuel injected from the injector 211 that is a fuel injection device are mixed (that is, an air-fuel mixture is formed), and the intake valve 203 is mixed. Is supplied to the combustion chamber 201. As will be described later, the injected fuel may adhere to the back of the intake valve 203 without being sufficiently evaporated (FIG. 3). In this embodiment, it is attempted to avoid or remove the adhering fuel by adjusting the opening / closing timing of the intake valve 203 or adjusting the lift amount.

  The variable valve operating apparatus 10 is, for example, VVT-i, and can be configured to change valve operating characteristics (for example, opening / closing timing or lift amount) of the intake valve 203 and the exhaust valve 204 using a cam-by-wire, an electromagnetically driven valve, or the like. Has been.

  The accelerator position sensor 216 detects the amount of depression of the accelerator pedal 226 by the driver, that is, the accelerator opening. It is determined whether or not there is an acceleration request based on the accelerator opening.

  The temperature sensor 220 is disposed in the vicinity of the combustion chamber 201 from the intake pipe 206, for example, and detects the temperature of the internal combustion engine 200 from the water temperature of cooling water (not shown) that cools the internal combustion engine 200. Based on the detected temperature, the state of the fuel injected from the injector 211 (for example, how much it is evaporated) is specified directly or indirectly.

  The throttle valve drive motor 217 opens and closes the throttle valve 214 based on the depression amount. The throttle valve 214 adjusts the amount of air fed from the intake pipe 234 into the combustion chamber 201. The surge tank 111 distributes the air sent to each combustion chamber and has the effect of suppressing the pressure fluctuation of the distributed air. The throttle position sensor 215 detects the opening degree of the throttle valve 214.

  The combustion chamber 201 is configured so that the air-fuel mixture sent from the intake pipe 206 inside can be burned by the spark plug 202. By this combustion, the piston 205 reciprocates up and down in the combustion chamber 201. The reciprocating motion is converted into the rotational motion of the crankshaft 219, and the vehicle on which the internal combustion engine 200 is mounted can be driven. The crank position sensor 218 detects the rotation angle (ie, crank angle) of the crankshaft 219.

  The exhaust pipe 210 is configured to be able to exhaust the exhaust gas generated inside the combustion chamber 201 via the exhaust valve 204. The air-fuel ratio sensor 221 is configured to detect the air-fuel ratio A / F2 of the exhaust gas and transmit it to the control device 100. The air-fuel ratio A / F2 thus detected is used for feedback correction of the combustion amount injected by the injector 211, for example.

  The turbocharger includes a compressor 41 and a turbine 42. The turbine 42 is disposed in the exhaust pipe 210, is rotated by receiving the kinetic energy of the exhaust gas, and is configured to be able to convert the rotational torque of the turbine 42 into the rotation of the compressor 41. The compressor 41 is disposed in the intake pipe 234 and can compress (supercharge) intake air by its rotation.

  The control device 100 controls the entire operation of the internal combustion engine 200. Among them, the intake valve control unit 110, the exhaust valve control unit 120, and the like are provided, and the variable valve apparatus 10 is controlled to adjust the overlap amount of the intake valve 203 and the exhaust valve 204 during the valve opening period. These are preferably a well-known electronic control unit (ECU), a central processing unit (CPU), a read only memory (ROM) storing a control program, and various data. It is configured as a logical operation circuit centering on a random read / write memory (RAM) to be stored. Furthermore, input ports for receiving input signals from various sensors (for example, accelerator opening, throttle opening, rotational speed Ne of the internal combustion engine 200, crank angle CA, air fuel efficiency A / F2, etc.) and various actuators (for example, possible Fluctuation valve device 10, throttle valve drive motor 217, etc.) are connected via a bus to an output port that sends a control signal.

  According to the configuration described above, the control device for the internal combustion engine according to the present embodiment includes the temperature sensor 220, the throttle valve drive motor 217, the variable valve operating device 10, the control device 100, and the like. Accordingly, the control device 100 controls the throttle valve driving motor 217 and the variable valve operating device 10 so as to change the valve operating characteristics of the throttle valve 214, the intake valve 203, and the exhaust valve 204. The flow of the intake air is adjusted according to the operating state of the internal combustion engine 200, and while the internal combustion engine 200 is started (particularly during cold start), fuel is prevented from adhering to the back of the intake valve 203, The fuel consumption can be improved.

(2) Operation Process The operation process of the control apparatus for an internal combustion engine according to this embodiment configured as described above will be described with reference to FIGS. 2 to 5 in addition to FIG.

  First, with reference to FIG. 2, a description will be given of the slow closing and the early closing of the intake valve 203 which are realized by using the variable valve operating apparatus 10 described above. FIG. 2 is a valve timing chart of the control device for the internal combustion engine according to the embodiment.

  The piston 205 of the internal combustion engine moves up and down in the combustion chamber 201, and the behavior in the combustion chamber 201 is expressed by a series of cycles such as suction, compression, combustion, expansion, and exhaust.

  In the Otto cycle, which is a general combustion cycle, the expansion ratio and the compression ratio have a substantially equal relationship. Therefore, it is conceivable to increase the compression ratio (≈expansion ratio) when trying to increase the thermal efficiency. However, simply increasing the compression ratio may cause knocking.

  Therefore, a technique called an Atkinson cycle (or Miller cycle) is disclosed for the Otto cycle. In this Atkinson cycle, by taking a large expansion ratio and changing the closing timing of the intake valve 203, the substantial compression ratio is lowered, and knocking is prevented while increasing the thermal efficiency. Specifically, as shown in FIG. 2 (a), the valve is closed late after bottom dead center, or FIG. 2 (b) is closed early before the bottom dead center. Thus, the substantial compression ratio can be lowered.

  More specifically, in the case of the slow closing shown in FIG. 2A, the intake valve 203 closes when the piston 205 is lowered to the bottom dead center and then reverses and rises to near the top dead center. By pushing back a considerable portion of the intake air sucked into the chamber 201 to the intake pipe 206, the intake amount in the combustion chamber 201 is changed (reduced) to a desired amount, and the substantial compression ratio is lowered. Can do. On the other hand, in the case of the early closing shown in FIG. 2B, the intake valve 203 is closed before the piston 205 is lowered to the bottom dead center, so that the intake air amount in the combustion chamber 201 has not yet reached the maximum, so that the combustion chamber 201 It is possible to change (decrease) the intake air amount to a desired amount and lower the substantial compression ratio. That is, knocking is prevented while increasing the thermal efficiency anyway. However, in comparison with the Otto cycle with the same displacement, the air-fuel mixture that can be sucked is limited, and the output that can be generated is reduced. This decrease in output is preferably supplemented by a turbocharger or an electric motor (not shown).

  The control apparatus for an internal combustion engine according to the present embodiment uses the slow closing in FIG. 2A or the early closing in FIG. 2B depending on the detected temperature when the internal combustion engine 200 is started. Thus, an excellent effect as described later with reference to FIG.

  Next, with reference to FIG. 3, a description will be given of an aspect of avoiding or removing the fuel adhering to the umbrella back of the intake valve 203 described above. FIG. 3 is a cross-sectional view schematically showing how the fuel adhering to the back of the umbrella of the intake valve according to the embodiment is removed.

  In FIG. 3, FIG. 3A according to the comparative example and FIG. 3B according to the present embodiment both show the valve opening timing state of the intake valve 203.

  In FIG. 3A according to the comparative example, an attempt is made to increase the flow rate of intake air by reducing the lift amount of the intake valve 203 and remove the attached fuel 500 attached to the back of the umbrella of the intake valve 203. However, the flow of intake air in the intake pipe 206 before passing through the intake valve 203 is not as strong as the flow of intake air when passing through the intake valve 203. Therefore, the fuel injected into the intake pipe 206 does not ride on the intake flow and may adhere to the back of the umbrella of the intake valve 203, and the attached fuel 500 once attached is difficult to desorb.

  On the other hand, in FIG. 3B according to the present embodiment, the throttle valve 214 is opened relatively large and the lift amount of the intake valve 203 is relatively large, so that the flow of intake air in the intake pipe 206 is early. Develop. Therefore, the fuel injected into the intake pipe 206 rides on the intake flow and can be prevented from adhering to the back of the umbrella of the intake valve 203, and the attached fuel 500 that has already adhered can be removed.

  Next, with reference to FIG. 4, a description will be given of how the pump loss varies depending on the opening degree of the throttle valve 214 described above. FIG. 4 is a sectional view of the intake pipe schematically shown in the internal combustion engine according to the embodiment.

  4A shows a state in which the throttle valve 214 is opened to an opening determined from the accelerator opening, and FIG. 4B shows a state in which the throttle valve 214 is larger than the opening determined from the accelerator opening. An open state (typically full open) is shown. Compared to the opening degree of the throttle valve 214 shown in FIG. 4A, it is larger than the opening degree of the throttle valve 214 shown in FIG. As a result, the pump loss caused by the intake air flowing through the intake pipe 206 being throttled by the throttle valve 214 is smaller in the case of FIG. 4B than in the case of FIG. In addition, in FIG. 4B, since the flow of the intake air is not blocked, it is possible to avoid the fuel from adhering to the back of the umbrella of the intake valve 203 and to remove the adhering attached fuel 500 (see FIG. 3). Therefore, it is desirable that the opening degree of the throttle valve 214 be as large as possible as shown in FIG. Preferably it should remain fully open. In the present embodiment, in order to meet such a demand, the opening amount of the throttle valve 214 is fully opened, and the intake air amount that should be adjusted by opening and closing the throttle valve 214 is the time when the intake valve 203 is closed as described with reference to FIG. By adjusting, the desired amount is adjusted.

  Next, referring to FIG. 5, a cold start routine will be described as a specific example of the operation process of the control device for the internal combustion engine. FIG. 5 is a flowchart showing the operation process of the control device for the internal combustion engine according to the embodiment.

  In FIG. 5, when the internal combustion engine 200 is started, particularly during a cold start, a cold start routine shown below is executed prior to normal travel. Specifically, first, the level of the coolant temperature T detected by the temperature sensor 220 and the predetermined temperature threshold value T1 are determined (step S1). Here, the “predetermined temperature threshold” is assumed to be a temperature at which the fuel injected into the intake pipe 206 is assumed to evaporate at a predetermined rate or more, in other words, sufficiently evaporated. The temperature is a temperature determined in advance by experience, experiment, simulation, or the like, for example, 80 °.

  Here, when the water temperature T is lower than the predetermined temperature threshold value T1 (step S1: Yes), that is, when it is assumed that the fuel is not sufficiently evaporated, the intake valve 203 of FIG. The control device 100 controls the variable valve gear 10 so that the Atkinson cycle is delayed (step S21).

  At this time, by adjusting the valve closing timing of the intake valve 203, a considerable portion of the intake air once sucked into the combustion chamber 201 is pushed back to the intake pipe 206, and the amount of intake air flowing into the combustion chamber 201 is adjusted. it can. Therefore, the throttle valve 214 may be opened (typically fully open) as shown in FIG. 4B, which is larger than the opening determined from the accelerator opening. As a result, the throttle action by the throttle valve 214 is suppressed, the flow in the intake pipe 206 is developed early, and the fuel injected into the intake pipe 206 is prevented from adhering to the back of the umbrella of the intake valve 203. As a result, the adhered fuel 500 that has already adhered can be removed. Here, since the pump loss is also reduced, the fuel efficiency is expected to be improved. In addition, as shown in FIG. 3B, the lift amount of the intake valve 203 also flows into the combustion chamber 201 from the intake pipe 206 or is pushed as the throttle valve 214 opens relatively large. Since the factors that hinder the flow of the fuel are further reduced, the effect of avoiding or removing the attached fuel 500 is further enhanced. When the valve is closed slowly as shown in FIG. 2A in such a relatively low temperature state, the overlap amount between the intake valve 203 and the exhaust valve 204 is larger than that of the early closing as shown in FIG. 2B. By reducing the size, deterioration of combustion can be avoided. This is because in a situation where the temperature is relatively low, exhaust gas that may blow back to the intake pipe 206 during the overlap period can be reduced.

  When the intake stroke ends in this way, the intake stroke is repeated again through the compression stroke, the combustion / expansion stroke, and the exhaust stroke. At this time, the water temperature T rises due to combustion in the combustion / expansion stroke.

  Then, it is determined by the control device 100 based on various parameters such as the water temperature T, the engine speed, and the torque (step S3). Here, when there is a return request (step S3: Yes), the cold start routine is terminated and the vehicle returns to normal running. On the other hand, when there is no return request yet (step S3: No), the above-described determination regarding the temperature is made again (step S1). Here, when the water temperature T is equal to or higher than the predetermined temperature threshold value T1 (step S1: No), that is, when it is assumed that the fuel is warmed up and the fuel is sufficiently evaporated, the intake valve 203 is placed behind the umbrella in the intake stroke. There is relatively little risk of adhesion. Therefore, in order to give priority to the improvement of fuel consumption, the control device 100 controls the variable valve apparatus 10 so that the intake valve 203 is quickly closed as shown in FIG. 2B (step S21). As a result, when adjusting the amount of intake air flowing into the combustion chamber 201, it is not necessary to push back a considerable portion of the intake air once sucked into the combustion chamber 201 to the intake pipe 206. Therefore, the temperature in the combustion chamber 201 can be efficiently increased, combustion can be improved, and fuel consumption can be improved.

  As described above, according to the operation processing described with reference to FIGS. 2 to 5 in addition to FIG. 1, the fuel consumption can be improved from the start while avoiding the fuel adhesion to the back of the umbrella of the intake valve 203.

  Although the above embodiment has been described using a single internal combustion engine, other modes may be used as long as the engine has valve operating means capable of an Atkinson cycle. For example, when an Atkinson cycle is used in an internal combustion engine, the present invention can be applied to a hybrid system that can supplement the output with an electric motor.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. The control device is also included in the technical scope of the present invention.

It is typical sectional drawing of the internal combustion engine provided with the control apparatus of the internal combustion engine which concerns on embodiment of this invention. It is a valve timing diagram of the control device for an internal combustion engine according to the embodiment. It is sectional drawing which shows typically a mode that the fuel adhering to the umbrella back of the intake valve which concerns on embodiment is removed. It is sectional drawing of the intake pipe shown typically in the internal combustion engine which concerns on embodiment. It is a flowchart which shows the operation | movement process of the control apparatus of the internal combustion engine which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 200 ... Internal combustion engine, 206 ... Intake pipe, 220 ... Temperature sensor, 217 ... Throttle valve drive motor, 201 ... Combustion chamber, 210 ... Exhaust pipe, 41 ... Compressor, 42 ... Turbine, 10 ... Variable valve gear, 100 ... Control apparatus

Claims (6)

A valve operating means capable of changing at least one of an opening / closing timing and a lift amount of an intake valve for performing intake into the combustion chamber of the internal combustion engine;
Temperature detecting means for detecting the temperature of the internal combustion engine;
A control device for an internal combustion engine, comprising: control means for controlling the valve operating means so as to change at least one of the detected temperature at the start of the internal combustion engine. In accordance with the detected temperature, the control means is configured to close the intake valve earlier than bottom dead center or close late after closing bottom dead center. The control device for an internal combustion engine according to claim 1, wherein the control means is controlled. The control means is configured to cause the intake valve to close slowly when the detected temperature falls below a predetermined temperature threshold at the start, and to close early if the detected temperature does not fall below the valve. The control device for an internal combustion engine according to claim 2, wherein the control means is controlled. 4. The control unit according to claim 1, wherein the control unit controls the valve operating unit so that the lift amount becomes a value exceeding a predetermined lift amount threshold value at the time of starting. 5. Control device for internal combustion engine. Provided in a flow path of an intake pipe communicating with the intake valve, further comprising a throttle valve opening and closing means for opening and closing a throttle valve for restricting a flow rate of intake air flowing through the intake pipe,
The control means opens and closes the throttle valve so that the opening degree of the throttle valve is larger than the opening degree determined from the accelerator opening degree when the detected temperature falls below a predetermined temperature threshold at the time of starting. The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the control means is controlled. The valve operating means can further change at least one of an opening / closing timing and a lift amount of an exhaust valve for exhausting from the combustion chamber,
When the detected temperature falls below the predetermined temperature threshold at the time of starting, the control means reduces the overlap amount in which both the intake valve and the exhaust valve are open compared to a case where the detected temperature does not fall below. The control unit for an internal combustion engine according to any one of claims 1 to 5, wherein the valve operating means is controlled to do so.

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