JP6061584B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine including a cylinder head in which an exhaust manifold is integrally formed.

  2. Description of the Related Art Conventionally, in a cylinder head that constitutes an internal combustion engine that is a multi-cylinder engine mounted on an automobile, the cylinder head includes an individual port through which exhaust gas from a combustion space flows and a collection port through which exhaust gases from a predetermined number of individual ports gather A system in which a collective exhaust port is formed is disclosed. In such a configuration, the exhaust performance is generally improved by shortening the warm-up time until the temperature at which the catalyst is activated by setting the distance between the cylinder head and the exhaust purification catalyst short. It is known to improve. In addition, a configuration has been proposed in which water jackets through which cooling water flows are arranged above and below the collecting port so as to quickly cool exhaust gas that becomes high temperature (see, for example, Patent Document 1 and Patent Document 2). .

  However, when the distance between the catalyst and the cylinder head is shortened, there is a concern that the temperature of the catalyst may be excessively increased.

  In addition, if the exhaust gas is cooled by flowing cooling water through the exhaust port assembly as in the above-mentioned patent document, it takes time to activate the catalyst at the cold start, and the exhaust performance deteriorates. .

JP 2007-187110 A JP 2009-2265 A

  The present invention pays attention to such a problem, and an object of the present invention is to provide an internal combustion engine that can achieve both improvement in exhaust gas quality and improvement in fuel consumption by early warm-up of the catalyst.

  In order to achieve such an object, the present invention takes the following measures.

That is, the internal combustion engine according to the present invention is an internal combustion engine having a cylinder head having a collecting port in which a plurality of exhaust ports merge in the cylinder head, from a main cooling water passage for introducing cooling water into the cylinder head. A collecting port cooling water passage that branches and allows cooling water to pass in the vicinity of the collecting port in the cylinder head, a branch point between the main cooling water passage and the collecting port cooling water passage, or the collecting port cooling water When the cooling water temperature in the vicinity of the collecting port exceeds a predetermined temperature, the cooling water is allowed to pass through the collecting port cooling water passage, and when the cooling water temperature is lower than the predetermined temperature, the collecting port is used. the passage of the cooling water in the cooling water passage is provided with a valve mechanism for prohibiting said regardless of whether the cooling water temperature and the engine load at the time of fuel cut The mechanism is characterized in that the closed state.

  Here, the cooling water passage for the collecting port is not limited to a mode in which it branches from the main cooling water passage and then joins the main cooling water passage again. That is, if the cooling water can pass through the vicinity of the collecting port by the valve mechanism, the collecting port cooling water passage may communicate with another cooling water passage such as a cylinder block separately from the main cooling water passage. good. Further, “when the cooling water temperature in the vicinity of the collecting port exceeds a predetermined temperature” is not only the case where the cooling water temperature in the vicinity of the collecting port is actually measured directly, but also the temperature of the sensor provided in another place and the so-called engine. It is a concept that includes a case where it is determined that a predetermined temperature has been exceeded by prediction from a load.

  If this is the case, the flow of the cooling water is made variable depending on the cooling water temperature of the cooling water passage for the collecting port provided in the cylinder head, so that the catalyst can be warmed up early during cold start. The catalyst can be prevented from being heated by cooling the vicinity of the collecting port. Accordingly, it is possible to provide an internal combustion engine that can achieve both improvement in exhaust gas quality and improvement in fuel consumption due to early warm-up of the catalyst.

  ADVANTAGE OF THE INVENTION According to this invention, the internal combustion engine which can improve the quality of exhaust gas by the early warming up of a catalyst and the improvement of a fuel consumption can be provided.

1 is a schematic configuration diagram according to an embodiment of the present invention. The other schematic block diagram. The typical plane sectional view of the important section concerning the embodiment. FIG. 4 is an end view taken along line AA according to FIG. 3. The flowchart which concerns on the same embodiment. The figure which shows the modification of the embodiment corresponding to FIG.

  An embodiment of the present invention will be described with reference to the drawings.

  In FIG. 1, the outline | summary of the internal combustion engine 100 for vehicles in this embodiment is shown. The internal combustion engine 100 is, for example, a spark ignition gasoline engine, and includes a plurality of, for example, three cylinders 1 (one of which is shown in FIG. 1). An injector 11 that injects fuel is provided in the vicinity of the intake port 13 of each cylinder 1. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives spark voltage generated by the ignition coil and causes spark discharge between the center electrode and the ground electrode. The ignition coil is integrally incorporated in a coil case together with an igniter that is a semiconductor switching element.

  The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port 13 of each cylinder 1. On the intake passage 3, an air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream.

  The exhaust passage 4 for discharging the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 1 from the exhaust port 14 of each cylinder 1 to the outside. An exhaust manifold 42 and a three-way catalyst 41 that is an exhaust purification catalyst are disposed on the exhaust passage 4. In the present embodiment, the configuration of the exhaust port 14 will be described in detail later.

In FIG. 2, the flow path of the cooling water passing through the internal combustion engine 100 will be described.
That is, the internal combustion engine 100 includes a water jacket W that is provided inside the cylinder block SB and the cylinder head SH and in which cooling water circulates. On the other hand, heat radiating means for lowering the coolant temperature is provided outside the internal combustion engine 100. As such heat radiating means, a water jacket W, a heater H for heating arranged on the driver's seat side of a vehicle (not shown), and a radiator R are arranged.

  The internal combustion engine 100 includes an electric pump for circulating the cooling water, and a thermostat SM interposed between the water jacket W of the radiator R and the radiator R. This thermostat SM prohibits the flow of cooling water to the radiator R when the cooling water temperature is lower than 84 ° C., for example, and allows the cooling water to flow when the cooling water is 84 ° C. or higher. Allow cooling. Further, in the present embodiment, the cooling water introduced into the internal combustion engine 100 from the heater H or the radiator R as the heat radiating means is introduced from a location near the upper portion of the combustion chamber in the cylinder head SH where the temperature rise is most significant. A so-called advance cooling mode is applied. The internal combustion engine 100 includes a water temperature sensor (not shown) for detecting the cooling water temperature. The water temperature sensor is usually provided in the vicinity of a portion where the cooling water is sent from the cylinder head SH to the radiator R. The radiator R is cooled not only by running wind but also by air blown by a radiator fan (not shown).

Therefore, the internal combustion engine 100 according to the present embodiment is a set that can branch from the main cooling water passage W1 for introducing cooling water into the cylinder head SH and allow the cooling water to pass in the vicinity of the collecting port 15 in the cylinder head SH. A cooling water passage for ports W2, and a valve mechanism X provided at a branching point of the main cooling water passage W1 and the collecting port cooling water passage W2 or the collecting port cooling water passage W2. In this embodiment, the valve mechanism X is mainly composed of an electromagnetic valve, and can take an open state in which cooling water can pass and a closed state in which passage of cooling water can be prohibited. Since the specific configuration of such a valve mechanism X can apply various configurations of existing electromagnetic valves, detailed description thereof will be omitted.

  3 and 4 show the main part of the cylinder head SH in which the collecting port 15 and the cooling water passage W2 for the collecting port are arranged.

  As shown in the figure, the cylinder head SH constitutes the upper part of the cylinders 1 arranged in a straight line in the longitudinal direction, and two intakes are provided on each of the intake side and the exhaust side for each cylinder 1. A plug mounting portion 16 for installing a spark plug 12 is formed in the approximate center of the cylinder 1 in plan view. The cylinder head SH has an intake port 13 that is branched for each cylinder 1 on the intake side, and an exhaust manifold 42 that is integrally provided on the exhaust side. The exhaust manifold 42 has an exhaust port 14 provided for each cylinder 1 and a collective port 15 formed by collecting the exhaust ports 14 in the vicinity of the end of the cylinder head SH. Further, on the inner surface side of the collective port 15, for example, port-side fins 15 a that protrude from the vertical direction are provided.

  On the other hand, the cooling water passage W2 for the collecting port shown in the figure is arranged so that the cooling water flows above and below the collecting port 15 as shown in FIG. 4, and there is no place corresponding to the port side fin 15a. The jacket side fins W2a are provided so as to be raised. In addition, although illustration is abbreviate | omitted in the same figure, the main cooling water channel | path W1 is distribute | arranged to the combustion chamber upper part vicinity like the past.

  The internal combustion engine 100 of the present embodiment is controlled by an ECU (Electronic Control Unit) 0. The ECU 0 is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like.

  The input interface includes a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal (N signal) b output from an engine rotation sensor that detects the rotation angle and rotation speed of the crankshaft, and an accelerator. An accelerator opening signal c output from a sensor that detects the depression amount of the pedal or the opening of the throttle valve 32 as an accelerator opening (in other words, a required load), the intake air temperature in the intake passage 3 (particularly, the surge tank 33), and An intake air temperature / intake pressure signal d output from a temperature / pressure sensor that detects intake pressure, a coolant temperature signal e output from a water temperature sensor that detects engine coolant temperature, and a plurality of cams on the intake camshaft or exhaust camshaft A cam angle signal (G signal) f output from the cam angle sensor is input at the angle.

  From the output interface, an open / close control signal h for opening or closing the valve mechanism X, an ignition signal i for the igniter of the spark plug 12, a fuel injection signal j for the injector 11, and a throttle valve 32 To output an opening operation signal k or the like.

  The processor of the ECU 0 interprets and executes a program stored in advance in the memory, calculates operation parameters, and controls the operation of the internal combustion engine 100. The ECU 0 acquires various information a, b, c, d, e, and f necessary for controlling the operation of the internal combustion engine 100 via the input interface, knows the rotation speed, and estimates the intake air amount filled in the cylinder 1. To do. Based on the rotational speed, the intake air amount, etc., various required fuel injection amounts, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, ignition timing, and opening / closing of the valve mechanism X Determine the parameters. As the operation parameter determination method itself, a known method can be adopted. The ECU 0 applies various control signals h, i, j, k through the output interface.

  Here, in this embodiment, when the valve mechanism X is ECU0 and the cooling water temperature in the vicinity of the collecting port 15 exceeds a predetermined temperature, the cooling water temperature is allowed to pass through the collecting port cooling water passage W2 and the cooling water temperature. When the temperature is lower than the predetermined temperature, control is performed so as to prohibit the passage of the cooling water in the collecting port cooling water passage W2.

  Hereinafter, control of the valve mechanism X according to the present embodiment will be described with reference to the flowchart of FIG. Here, the control according to the flowchart is not applied during idle operation or during fuel cut. That is, it is necessary to maintain the exhaust temperature in order to avoid a decrease in the temperature of the three-way catalyst 41 during the idle operation or fuel cut. Therefore, even if it is estimated that the cooling water temperature in the vicinity of the collecting port 15 is high, the valve mechanism X is closed during idle operation or fuel cut.

  First, when the cooling water temperature is detected during an operation other than the idling operation or the fuel cut (step S1), the cooling water for the collecting port in the vicinity of the collecting port 15 is determined from the cooling water temperature and the state of the internal combustion engine, particularly the engine load. An estimated cooling water temperature that is an estimated value of the cooling water temperature in the passage W2 is calculated (step S2). Then, it is determined whether the estimated cooling water temperature is lower than a predetermined temperature or higher than a predetermined temperature (step S3). Here, the “operating state” is determined based on the various information a, b, c, d, e, and f necessary for the operation control of the internal combustion engine 100. The “predetermined temperature” is set to a temperature slightly lower than the boiling point of the cooling water. Since various additives are dissolved in ordinary water (pure water), the cooling water has a boiling point of, for example, about 110 ° C., which is higher than that of ordinary water. Therefore, the predetermined temperature may be a temperature exceeding 100 ° C.

  If the estimated cooling water temperature is equal to or higher than the predetermined temperature in step S3 and the valve mechanism X is closed (step S4), the valve mechanism X is opened (step S5), and the cooling for the collecting port is performed. The cooling water in the water passage W2 flows so that it can be circulated from the internal combustion engine 100 to the heat dissipating means like the other cooling water. In this embodiment, the higher the estimated cooling water temperature is, the higher the opening degree of the valve mechanism X is set, so that the collecting port can be cooled more quickly. If the valve mechanism X is in the open state, the process is terminated as it is. In this case, it is desirable to take measures to further cool the internal combustion engine 100 by a method other than the operation of the valve mechanism X.

Estimated coolant temperature in the other step S3 is lower temperature than the predetermined temperature, and, when the valve mechanism X is in the open state (step S6), the valve mechanism X and the closed state (step S7) . If the valve mechanism X is in the closed state, the process is terminated as it is. In this case, warming-up of the collecting port 15 and the three-way catalyst 41 is promoted.

  With the configuration as described above, the internal combustion engine 100 according to the present embodiment makes the cooling water flow variable according to the cooling water temperature of the collecting port cooling water passage W2 provided in the cylinder head SH. It is possible to prevent the three-way catalyst 41 from being heated by performing early warm-up of the three-way catalyst 41 during the intermediate start and cooling the vicinity of the collecting port 15 after warming up. As a result, it is possible to provide the internal combustion engine 100 that can achieve both the improvement of the exhaust gas quality and the improvement of the fuel consumption due to the early warm-up of the three-way catalyst 41.

  Further, according to the present embodiment, even if the valve mechanism X is in the closed state, the valve mechanism X is opened before the cooling water temperature in the vicinity of the collecting port 15 boils. The impact of boiling is avoided in advance. In addition, the present embodiment contributes to the improvement of fuel consumption by effectively reducing the opportunity to take measures such as the fuel increase that has been performed to lower the temperature of the three-way catalyst 41 compared to the conventional one.

  In particular, in the present embodiment, port-side fins 15a are provided on the collecting port 15 side to increase the surface area of the inner surface of the collecting port. Further, a jacket-side fin W2a is provided on the side of the collecting port cooling water passage W2 to increase the surface area of the inner surface of the collecting port cooling water passage W2. By doing so, heat exchange between the collecting port 15 and the collecting port cooling water passage is promoted, and temperature control in the vicinity of the collecting port 15 can be performed more promptly.

<Modification>
Hereinafter, modifications of the present embodiment will be described. In addition, in the said modification, while attaching | subjecting the same code | symbol about what is corresponded to the component in the said embodiment, the detailed description is abbreviate | omitted.

  FIG. 6 shows an aspect in which the cooling water temperature detecting means S for directly detecting the cooling water temperature in the cooling water passage W2 for the collecting port is provided when the valve mechanism X is an electromagnetic type. That is, the cooling water temperature in the vicinity of the collective port 15 is not limited to the mode estimated from the value of the existing water temperature sensor or the operation status. In addition, as shown in the figure, the cooling water temperature detecting means S is provided at a position where the cooling water temperature is highest. Thereby, while being able to grasp | ascertain the cooling water temperature of the collection port 15 vicinity more correctly, the local boiling of a cooling water can be avoided effectively.

  Although the embodiment of the present invention has been described above, the specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above-described embodiment, the cooling water channel for the collecting port is shown as two paths provided above and below the collecting port. There may be. In the above-described embodiments and modifications, the valve mechanism is an electromagnetic valve, but of course, a thermostat that opens and closes depending on the cooling water temperature may be applied. When using such a thermostat, it is preferable to provide the location where the thermostat is disposed at a position where the cooling water temperature is highest in the vicinity of the collecting port as in the above-described modification. Thereby, the control of the valve mechanism can be realized without the control by the ECU.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The present invention can be used as an internal combustion engine having a cylinder head integrally formed with an exhaust manifold.

DESCRIPTION OF SYMBOLS 100 ... Internal combustion engine 14 ... Exhaust port 15 ... Collecting port SH ... Cylinder head W1 ... Main cooling water passage W2 Cooling water passage for collecting port X ... Valve mechanism

Claims (1)

An internal combustion engine having a cylinder head having a collecting port where a plurality of exhaust ports merge in the cylinder head,
A cooling water passage for a collecting port that branches from a main cooling water passage that introduces cooling water into the cylinder head and allows the cooling water to pass through the cylinder head in the vicinity of the collecting port;
When the cooling water temperature in the vicinity of the collecting port exceeds a predetermined temperature provided at a branch point of the main cooling water passage and the collecting port cooling water passage or in the collecting port cooling water passage, the collecting port cooling water If the cooling water temperature as well as permit the passage of cooling water in the passage is lower than the predetermined temperature is provided a valve mechanism for prohibiting the passage of cooling water in the port set for the cooling water passage, at the time of fuel cut An internal combustion engine that closes the valve mechanism regardless of the coolant temperature and the engine load .

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