Ignition device

Abstract

Ignition device (1) for internal combustion, the ignition device comprising: a spark plug (2) which contains an additional chamber (21) and an injection hole (22) from which a flame from the additional chamber is to be injected into a main combustion chamber (3); an operational information acquisition unit (4) configured to acquire operational information regarding an operating state of the internal combustion; and an ignition control unit (5) configured to control an ignition energy profile that influences an ignition state of an air-fuel mixture based on the operating information obtained by the operating information acquisition unit, wherein the ignition control unit is configured to: to compare a predetermined target load with a load obtained by the operational information acquisition unit, to reduce the ignition energy to be supplied to the spark plug in response to a comparison result indicating that the achieved load is higher than the target load, and to increase the ignition energy to be supplied to the spark plug in response to the comparison result indicating that the achieved load is lower than the target load.

Description

Cross-reference to related registration

[0001] The present application is based on Japanese patent application No. 2019-197905, filed on October 30, 2019, the disclosure of which is incorporated herein in full by reference. Technical field

[0002] The present disclosure relates to an ignition device. background

[0003] There is an ignition device for internal combustion that injects a flame from an auxiliary chamber into a main combustion chamber. JP 2018 - 178 966 A, for example, discloses as such an ignition device a configuration that includes a pressure sensor which detects the pressure within the auxiliary chamber. In this configuration, the variation in the ignition timing in the main combustion chamber is reduced by adjusting the ignition timing according to an operating condition of the internal combustion and the pressure within the auxiliary chamber detected by the pressure sensor, and by correcting the ignition timing based on the shape of the auxiliary chamber, which includes the volume of the auxiliary chamber, the number of injection holes, and the radius of the injection hole.Furthermore, a configuration is also disclosed which dynamically corrects the ignition timing by means of a feedback control to prevent the occurrence of knocking due to temporal wear or the like of the ignition device. Citation list for patent literature JP 2018 - 178 966 A JP 2015 - 190 338 A JP S58 - 154 869 U JP 2009 - 36 157 A DE 102013 010 685 A1 Summary of the invention

[0004] In an ignition device containing an auxiliary chamber, data regarding the injection speed, length, or similar parameters of the flame to be injected from the injection holes change automatically according to operating conditions, such as load and internal combustion speed, as well as the volume of the auxiliary chamber and the radius of the injection hole. Conversely, the data regarding the flame to be injected, such as the volume of the auxiliary chamber and the number of injection holes, are set to inject an ideal flame under a specific condition. However, with this type of data, it becomes difficult to ensure that an ideal flame is injected over a wide operating range, resulting in reduced thermal efficiency and a deterioration of fuel efficiency in most operating ranges.

[0005] If, under high load, unburned air-fuel mixture remains at the end of a bore that is a peripheral section within a main combustion chamber, knocking is likely to occur. To prevent such knocking, it is effective to increase the injection velocity of the flame being injected from the injection ports. This ensures that the injected flame reaches the bore end immediately, before knocking occurs, thus allowing the air-fuel mixture to be combusted. On the other hand, excessive pressure propagation creates combustion noise, which a knock sensor, which detects combustion oscillations, may falsely interpret as knocking if the flame injection velocity is excessively high.If knocking is incorrectly detected, the ignition timing is automatically delayed based on a control value, resulting in reduced fuel efficiency. Furthermore, combustion noise is unpleasant for the user, making it desirable to prevent it. Therefore, simply increasing the injection speed of the injected flame is insufficient to improve the fuel efficiency of internal combustion, and further improvements are possible.

[0006] The present disclosure aims to provide an ignition device that can achieve an improvement in fuel efficiency.

[0007] A first aspect of the present disclosure is an ignition device for internal combustion, wherein the ignition device comprises: a spark plug which contains an additional chamber and an injection hole from which the flame from the additional chamber is to be injected into the main combustion chamber; an operational information acquisition unit configured to acquire operational information regarding the operating status of the internal combustion; and an ignition control unit configured to control an ignition energy profile that influences the ignition state of an air-fuel mixture, based on the operating information obtained by the operating information acquisition unit, wherein the ignition control unit is configured to: to compare a predetermined target load with a load obtained by the operational information acquisition unit, to reduce the ignition energy to be supplied to the spark plug in response to a comparison result indicating that the achieved load is higher than the target load, and to increase the ignition energy to be supplied to the spark plug in response to the comparison result indicating that the achieved load is lower than the target load.

[0008] A second aspect of the present disclosure is an ignition device for internal combustion, wherein the ignition device comprises: a spark plug which contains an additional chamber and an injection hole from which the flame from the additional chamber is to be injected into the main combustion chamber; an operational information acquisition unit configured to acquire operational information regarding the operating status of the internal combustion; and an ignition control unit configured to control an ignition energy profile that influences the ignition state of an air-fuel mixture, based on the operating information obtained by the operating information acquisition unit, wherein the ignition control unit is configured to: to determine whether the knocking condition is met, and to increase the ignition energy to be supplied to the spark plug in response to determining that the knocking condition is met.

[0009] A third aspect of the present disclosure is an ignition device for internal combustion, wherein the ignition device comprises: a spark plug which contains an additional chamber and an injection hole from which the flame from the additional chamber is to be injected into the main combustion chamber; an operational information acquisition unit configured to acquire operational information regarding the operating status of the internal combustion; and an ignition control unit configured to control an ignition energy profile that influences the ignition state of an air-fuel mixture, based on the operating information obtained by the operating information acquisition unit, wherein the ignition control unit is configured to: to determine whether the operating condition fulfills a condition for the occurrence of knocking, to determine whether, in response to finding that the knocking condition is met, it is possible to prevent knocking by increasing the ignition energy to be supplied to the spark plug, and the ignition timing in response to the determination that it is not possible to prevent or delay the knocking.

[0010] The ignition system, as described above, is configured so that the ignition energy profile, which influences the ignition state of the air-fuel mixture, is controlled based on operating information. Even if an operating condition changes, the ignition energy profile is therefore controlled accordingly, ensuring that the flame is injected from the auxiliary chamber's injection holes at an optimal injection velocity and duration. This prevents knocking by increasing the flame injection velocity in high-load operation, prevents excessively high flame injection velocity, and avoids falsely detecting knocking based on combustion noise.According to the above, it is possible to prevent both knocking and combustion noise, as well as to improve fuel efficiency.

[0011] As previously described, it is possible, according to the aspect described above, to provide an ignition device that achieves an improvement in fuel efficiency.

[0012] It should be noted that the reference numerals placed in brackets in the claims indicate correspondence relationships of specific means described in the embodiments described later and do not limit the technical scope of the present disclosure. Brief description of the drawings

[0013] The preceding and further tasks, features and advantages of the present disclosure will become clearer through the following detailed description with reference to the attached drawings, wherein Fig. 1 is a conceptual diagram illustrating a configuration of an ignition device in a first embodiment, Fig. 2 is a block diagram illustrating the configuration of the ignition device in the first embodiment, Fig. 3(a) is a conceptual cross-sectional diagram illustrating a configuration of a spark plug, and Fig. 3(b) a bottom view of the spark plug in the first embodiment is, Fig. 4(a) to Fig. 4(c) conceptual diagrams are those that illustrate aspects of flame injection in the first embodiment, Fig. 5(a) to Fig. 5(c) conceptual diagrams are those that indicate a correspondence relationship between a load, a rotational speed and an ignition energy profile in the first embodiment, Fig. 6 is a conceptual diagram illustrating one aspect of controlling the ignition energy profile in the first embodiment, Fig. 7 is a view that illustrates a control sequence of the ignition device in the first embodiment, Fig. 8(a) is a conceptual diagram illustrating a correspondence relationship between a load, a rotational speed and an ignition energy profile in a first modified example, and Fig. 8(b) is a conceptual diagram illustrating a correspondence relationship between a load, a rotational speed and an ignition energy profile in a second modified example, Fig. 9(a) to Fig. 9(c) Views are those that illustrate the results of an evaluation test for the first embodiment, Fig. 10 is a block diagram illustrating a configuration of an ignition device in a second embodiment, Fig. 11 is a conceptual diagram illustrating waveforms before and after a transformation in the second embodiment, Fig. 12(a) is a conceptual diagram illustrating a configuration of an ignition coil in a third modified example, and Fig. 12(b) is a conceptual diagram illustrating one aspect of controlling an ignition energy profile in the third modified example, Fig. 13(a) is a conceptual diagram illustrating one aspect of controlling an ignition energy profile in a fourth modified example, Fig. 13(b) is a conceptual diagram illustrating one aspect of controlling an ignition energy profile in a fifth modified example, Fig. 13(c) is a conceptual diagram illustrating one aspect of controlling an ignition energy profile in a sixth modified example, and Fig. 13(d) is a conceptual diagram illustrating one aspect of controlling an ignition energy profile in a seventh modified example. Description of the embodiments (First embodiment)

[0014] The embodiments of the previously described ignition device are achieved using Fig. 1 to Fig. 8 described.

[0015] An ignition device 1 in the present embodiment is, as in Fig. Figure 1 illustrates an ignition device for internal combustion and contains, as shown in Fig. Figure 2 illustrates a spark plug 2, an operating information acquisition unit 4 and an ignition control unit 5.

[0016] The spark plug 2 contains an additional chamber 21 and injection holes 22, from which a flame from the additional chamber 21 to the main combustion chamber 3, as in Fig. Figure 3 illustrates what should be injected.

[0017] The operational information acquisition unit 4, which is located in Fig. 1 and Fig. As illustrated in 2, operational information regarding an operating state of the internal combustion is obtained.

[0018] The ignition control unit 5 controls an ignition energy profile, which influences the ignition state of an air-fuel mixture, based on the operating information obtained by the operating information acquisition unit 4.

[0019] The ignition device 1 of the present embodiment is described in detail below.

[0020] As in Fig. Figure 3 illustrates that in the ignition device 1 of the present embodiment, the spark plug 2 is attached to a cylinder head 101 of the internal combustion, such that a tip of the spark plug 2 exposes the main combustion chamber 3 of the internal combustion. As shown in Fig. As illustrated in Figure 3, the auxiliary chamber 21 is provided at the tip of the spark plug 2. A discharge gap G is formed within the auxiliary chamber 21, with a plurality of injection holes 22, which allow the auxiliary chamber 21 to communicate with the main combustion chamber 3, being formed on a wall section forming the auxiliary chamber 21. It should be noted that, although in the present embodiment the wall section forming the auxiliary chamber 21 is formed separately from a housing of the spark plug 2, the wall section and the housing of the spark plug 2 can be formed integrally as one part. Furthermore, the wall section forming the auxiliary chamber 21 can be formed integrally with the cylinder head 101.

[0021] As in Fig. 3(a) and Fig. As illustrated in Figure 3(b), the auxiliary chamber 21 is connected to the main combustion chamber 3 via the plurality of injection holes 22. The shape of the injection holes 22 is not limited to a particular one, and the arrangement of the injection holes 22 is not limited. In the present embodiment, as shown in Figure 3(b), the auxiliary chamber 21 is connected to the main combustion chamber 3 via the plurality of injection holes 22. Fig. Figure 3(b) illustrates the injection holes 22 being arranged concentrically around a spark plug shaft center 2a of the spark plug 2 when the spark plug 2 is viewed from a tip side Y1 to a base end side Y2. A centerline 22a of the injection hole 22 extends such that it is separated from the spark plug shaft center 2a of the auxiliary chamber 21 in the direction of the main combustion chamber 3. In the present embodiment, data such as a shape of the auxiliary chamber 21, a radius, an arrangement, or the like of the injection holes 22 are set such that the flame travels from the injection holes 22 to a bore end 103 within the main combustion chamber 3, as shown in Figure 3(b). Fig. 4(b) illustrates what is injected.

[0022] As in Fig. As illustrated in Figure 5(a), an engine operating range can be expressed as a relationship between an engine speed and a load, with an upper limit of the engine operating range specified as a reference L1. Furthermore, in the engine operating range, in a high-load range S, which is more heavily loaded than a reference L2, there is a possibility of knocking occurring if the ignition is performed at an ignition timing at which the best fuel efficiency can be achieved. As shown in Fig. As illustrated in Figure 4(a), in a case where the injection velocity of the flame F to be injected from the auxiliary chamber 21 is low and the flame F does not reach the bore end 103 within the main combustion chamber 3, knocking is caused by an unburned air-fuel mixture U present at the bore end 103, which achieves auto-ignition when compressed by a combustion gas. On the other hand, in a case where the injection velocity of the flame F is excessively high, as in Figure 4(a), knocking occurs due to an unburned air-fuel mixture U present at the bore end 103, which achieves auto-ignition when compressed by a combustion gas. Fig. Figure 4(c) illustrates the possibility that a pressure wave, generated by adiabatic compression from the outgoing flame F, propagates within the main combustion chamber 3 and produces a combustion noise. To solve these problems, the knocking, as shown in Fig. 4(b) illustrates that, by adjusting the injection speed of the flame using setting data relating to the shape of the auxiliary chamber 21 and the radius, arrangement, or the like of the injection holes 22, as previously described, this is prevented in a predetermined operating state in which the flame is allowed to reach the bore end 103, whereby the combustion noise is reduced to an acceptable range. In the present embodiment, as shown in Fig. Figure 5(a) illustrates the previously described data set based on an operating condition at point A, whereby knocking is prevented and the combustion noise in a first high load range Sa containing point A is reduced from the multiple high load ranges S to an allowable range.

[0023] The operational information acquisition unit 4, which is located in Fig. As illustrated in Figure 1, the operating information regarding the operating state during internal combustion of a vehicle on which the ignition device 1 of the present embodiment is mounted is obtained. Examples of operating information can be, for example, a load, a rotational speed, a pressure in the cylinder, and the like during internal combustion. Such operating information can be obtained, for example, from an ECU 6, which is a control unit for internal combustion. The operating information obtained by the operating information acquisition unit 4 is stored in a storage unit 60, which is located in Fig. 2 is illustrated, saved.

[0024] As in Fig. As illustrated in Figure 2, the ignition control unit 5 includes a knock detection unit 51, a combustion noise detection unit 52, and an ignition energy control unit 53. The knock detection unit 51 determines whether a knocking condition is met during internal combustion or whether knocking occurs based on operating information obtained by the operating information acquisition unit 4. The knocking condition is pre-stored in a memory unit 61. The knocking condition may include a load being lower than a predetermined setpoint load. In the present embodiment, as shown in Figure 2, the ignition control unit 51 determines whether a knocking condition is met during internal combustion or whether knocking occurs based on operating information obtained by the operating information acquisition unit 4. The knocking condition is pre-stored in a memory unit 61. Fig. Figure 5(a) illustrates the first high load range Sa being set as a target load, where the condition after which knocking occurs is a condition according to which the load belongs to a second high load range Sb which is lower than the target load.

[0025] Furthermore, the combustion noise determination unit 52 determines whether a condition under which a combustion noise equal to or greater than a predetermined reference occurs is met during internal combustion, or whether the combustion noise occurs based on the operating information obtained by the operating information acquisition unit 4. The condition under which the combustion noise occurs is pre-stored in the storage unit 61. The condition under which the combustion noise occurs may include a condition under which a load is higher than a predetermined target load. In the present embodiment, as shown in Fig. Figure 5(a) illustrates that the first high-load range Sa is set as a target load, wherein the condition under which the combustion noise occurs is a condition according to which the load belongs to a third high-load range Sc that is higher than the target load. Furthermore, the condition under which the combustion noise occurs can include a condition according to which the pressure oscillation that occurs together with the injection of the flame through the injection holes 22 is greater than a predetermined reference value.

[0026] The ignition energy control unit 53, which is in Fig. As illustrated in Figure 2, the ignition energy profile is controlled based on a determination result of the knock determination unit 51 or the combustion noise determination unit 52. The ignition energy profile is an element that influences the ignition state of an air-fuel mixture and can, for example, control a discharge current at the spark plug 2, which is located in Fig. Figure 1 illustrates the number of repetitions and a period during which the discharge current flows, as well as a coil charging period and a coil discharging period at the ignition coil 20, which contains a primary coil 24 and a secondary coil 25, an aspect according to which a coil circuit is switched in a case where the ignition coil 20 contains a plurality of coil circuits, an ignition timing, and the like. In the present embodiment, the ignition energy control unit 53 controls the operation of an ignition unit 23, which contains a switching element provided on an ignition coil 20. The ignition energy control unit 53 controls, as the ignition energy profile, the ignition energy to be supplied to the spark plug 2 by means of an ON / OFF control of the ignition unit 23. For example, as shown in Figure 1, the ignition energy control unit 53 can be used to control the ignition energy profile. Fig. Figure 6(a) illustrates that the ignition energy to be supplied to spark plug 2 can be reduced by shortening an ON period of the ignition unit 23 in order to shorten a charging period to the ignition coil 20. Although not illustrated, the ignition energy to be supplied to spark plug 2 can also be increased by lengthening the charging period. As shown in Fig. As illustrated in Figure 6(b), the ignition energy to be supplied to spark plug 2 can also be reduced by lowering the charging voltage at the ignition coil 20. Although not illustrated, the ignition energy to be supplied to spark plug 2 can also be increased by increasing the charging voltage.

[0027] The ignition energy control unit 53 can control the ignition energy profile, for example, based on a correspondence relationship between the operating information and the preset ignition energy profile. This correspondence relationship can be expressed as a kind of characteristic map of the ignition energy profile with respect to the operating information; that is, it can be expressed as an expression derived from a theoretical model or a relational expression obtained from a physical model through an acceleration test. In the present embodiment, the ignition energy control unit 53 controls the ignition energy profile based on a characteristic map that expresses the correspondence relationship between a load, a rotational speed, and the ignition energy profile, which is preset in Fig. 5(b) illustrates this. The characteristic map is stored in advance in memory unit 61.

[0028] The control sequence of the ignition device 1 in the present embodiment is described below.

[0029] First, in step S1, which is in Fig. Figure 7 illustrates how the operating information of the internal combustion is obtained by the operating information acquisition unit 4 and stored in the storage unit. Subsequently, the knock determination unit 51 determines the knock in step S2, which is shown in Figure 7. Fig. Figure 7 illustrates whether a condition for the occurrence of knocking is met based on the operating information obtained by the operating information acquisition unit 4. In the present first embodiment, the knock determination unit 51 determines whether the load obtained by the operating information acquisition unit 4 belongs to the second high-load range Sb, which is lower than the first high-load range Sa, as shown in Fig. Figure 5(a) illustrates the target load.

[0030] In a case where step S2, which is in Fig. As illustrated in Figure 7, it is determined that the knocking condition is met; that is, in a case where it is determined that the load belongs to the second high-load range Sb, processing continues with YES in step S2. Subsequently, in step S3, it is determined whether the ignition energy of the spark plug 2 can be increased. This determination can be carried out by the combustion noise determination unit 52, which determines whether the combustion noise condition is met. In the present first embodiment, the operating information acquisition unit 4 obtains the pressure oscillation that occurs together with the injection of the flame from the injection holes 22, and the combustion noise determination unit 52 compares the pressure oscillation with a predetermined, set value to determine whether the pressure oscillation is equal to or greater than the set value.

[0031] In a case where step S3, which is in Fig. As illustrated in Figure 7, if it is determined that the pressure oscillation is not equal to or greater than the set value, it is determined that the ignition energy may be increased, with processing continuing with NO in step S3. Subsequently, in step S4, the ignition energy to be supplied to spark plug 2 is increased by the ignition energy control unit 53, and the control is terminated. For example, as shown in Figure 7, the following applies: Fig. Figure 5(b) illustrates how the ignition energy to be supplied to spark plug 2 is increased based on the map that shows the relationship between the load, the rotational speed, and the ignition energy profile. This makes it possible to cause the flame F to increase by increasing the injection speed of the flame F relative to a relatively low speed, as shown in Figure 5(b). Fig. Figure 4(a) illustrates the end of borehole 103, as shown in Fig. 4(b) illustrates this. Consequently, the unburned air-fuel mixture Q at the borehole end 103 is reduced, thus preventing knocking.

[0032] On the other hand, there is a case in which step S3, which is in Fig. As illustrated in Figure 7, it is determined that the pressure oscillation is equal to or greater than the set value. In other words, there is a case in which the motor operating range, depending on the motor, includes a fourth high-load range Sd, which is shown in Figure 7. Fig. As illustrated in Figure 5(c), in the fourth high-load range Sd, the obtained operating information also fulfills a combustion noise occurrence condition, in which the combustion noise exceeds a permissible range, while the obtained operating information also fulfills the knock occurrence condition. Thus, in a case where it is determined in step S3 that the load belongs to the fourth high-load range Sd, although it is desired to increase the flame injection speed to prevent knocking, the flame injection speed has already exceeded the permissible combustion noise range. Therefore, it is determined that the ignition energy cannot be increased, and processing continues with NO in step S3. Consequently, in step S5, the ignition energy control unit 53 delays the ignition timing to prevent knocking, and the control process is terminated.

[0033] Furthermore, the processing continues in a case where in step S2, which is in Fig. As illustrated in Figure 7, if the condition of knocking is not met, the unit proceeds to step S2 with NO. Subsequently, in step S6, the combustion noise determination unit 52 determines, based on the operating information obtained by the operating information acquisition unit 4, whether the condition of combustion noise is met. In the present first embodiment, it is determined whether the load obtained by the operating information acquisition unit 4 corresponds to the third high-load range Sc, which is higher than the first high-load range Sa, which corresponds to the target load. Fig. 5(a) is illustrated, corresponds to, belongs. In a case where it is determined in step S6 that the condition of the occurrence of the combustion noise is not met, the processing continues with NO in step S6 and the control is terminated.

[0034] On the other hand, the processing continues in a case where step S6, which is in Fig. Figure 7 illustrates that it is determined that the condition of the occurrence of combustion noise is met, i.e., in a case where it is determined that the load belongs to the third high load range Sc, proceed with JA in step S6.

[0035] Subsequently, in step S7, the ignition energy control unit 53 reduces the ignition energy to be supplied to spark plug 2, and the control process is terminated. This reduces the combustion noise by decreasing the injection speed of the flame F from an excessively high speed, as in Fig. 4(c) illustrates a speed at which the flame F reaches the end of the bore 103, as in Fig. 4(b) illustrates, achieved, reduced to the allowed range.

[0036] The operational effects of the ignition device 1 of the internal combustion in the present embodiment are described in detail below.

[0037] The ignition device 1 of the internal combustion in the present first embodiment controls the ignition energy profile, which influences the ignition state of the air-fuel mixture, based on the operating information. This allows the flame to be injected from the injection holes 22 of the auxiliary chamber 21 with an optimal injection speed and duration, even if the operating state changes, by controlling the ignition energy profile in accordance with the operating state. This prevents knocking by increasing the flame injection speed in the high-load range and also prevents the erroneous detection of knocking based on combustion noise by preventing an excessive increase in the flame injection speed.This prevents both knocking and combustion noise, thus improving fuel efficiency.

[0038] Furthermore, in the present first embodiment, the ignition energy profile includes the ignition energy to be supplied to the spark plug 2. This allows for highly accurate control of the flame injection speed at the spark plug 2, thus preventing both knocking and combustion noise, and further improving fuel efficiency.

[0039] Furthermore, in the present first embodiment, the operating information includes at least one parameter relating to the load and rotational speed during internal combustion. This allows the ignition energy profile to be controlled according to the load and rotational speed of the internal combustion, making it easier to adjust the flame injection speed to the operating conditions, even in cases where the flame injection speed changes automatically, thus further improving fuel efficiency.

[0040] Furthermore, in the present first embodiment, the ignition control unit 5 compares the load obtained by the operating information acquisition unit 4 with the predetermined target load. If the comparison indicates that the obtained load is higher than the target load, the ignition control unit 5 reduces the ignition energy to be supplied to the spark plug 2. Conversely, if the comparison indicates that the obtained load is lower than the target load, the ignition control unit 5 increases the ignition energy to be supplied to the spark plug 2.This makes it possible to prevent the occurrence of combustion noise by reducing the injection speed of the flame in a condition where combustion noise is likely to occur, as well as to prevent the occurrence of knocking by increasing the injection speed of the flame in a condition where knocking is likely to occur.

[0041] Furthermore, in the present first embodiment, the ignition control unit 5 determines whether the pressure oscillation, together with the injection of the flame from the injection holes 22, fulfills the condition for the occurrence of combustion noise. In a case where it is determined that the condition for the occurrence of combustion noise is fulfilled, it reduces the ignition energy to be supplied to the spark plug 2. This makes it possible to prevent the occurrence of combustion noise with high accuracy.

[0042] Furthermore, in the present first embodiment, the ignition control unit 5 determines whether the knocking condition is met, and in such a case, increases the ignition energy to be supplied to the spark plug 2. This makes it possible to prevent knocking with high accuracy.

[0043] Furthermore, in the present first embodiment, the ignition control unit 5 determines whether the operating condition meets the condition for the occurrence of knocking. If it is determined that the condition for the occurrence of knocking is met, it determines whether the knocking can be prevented by increasing the ignition energy to be supplied to the spark plug 2. Consequently, if it is determined that knocking cannot be prevented, the ignition control unit 5 retards the ignition timing. Therefore, if knocking cannot be prevented by increasing the ignition energy to be supplied to the spark plug 2, it is possible to prevent knocking without increasing the combustion noise by retarding the ignition timing.

[0044] It should be noted that point A can be set as an operating condition for the setting data, such as the shape of the additional chamber 21, and the radius and arrangement of the injection holes 22, taking into account an engine type and other conditions, with point A being as in a first modified example that is in Fig. As illustrated in Figure 8(a), point A can be set at a position near reference L1, which indicates the upper limit of the engine operating range. In this case, the high-load range S, in which knocking can occur, essentially consists of the first high-load range Sa and the second high-load range Sb. Furthermore, point A can be set as in a second modified example shown in Figure 8(a). Fig. As illustrated in 8(b), the ignition energy control unit 53 can be set at a position close to the reference L2 for the occurrence of knocking. In this case, the high-load range S essentially consists of the first high-load range Sa and the third high-load range Sc. In both modified examples, the ignition energy control unit 53 determines the ignition energy to be supplied to the spark plug 2 based on the map that shows the relationship between the load, the speed, and the ignition energy profile, which is specified in the map. Fig. 5(b) illustrates that, in the same way as in a case of the first embodiment, operational effects are provided which are the same as those in the first embodiment. (Evaluation test)

[0045] In the first embodiment, an evaluation test was performed to determine the relationship between the ignition energy to be supplied to spark plug 2 and the injection of the flame. The ignition energy to be supplied to spark plug 2 of a test object was set to 25 mJ, 50 mJ, and 100 mJ, respectively, at the ignition device 1 in the first embodiment, as shown in Examples 1 to 3. In an evaluation procedure, a flame injection state at a time 4.5 ms after the start of the discharge was simulated based on hydromechanics.

[0046] According to the present evaluation test, as in Fig. 9(a) to Fig. 9(c) illustrates and confirms that, in accordance with the increase in the ignition energy to be supplied to spark plug 2, the length of the flame will increase and the injection speed of the flame will increase.

[0047] As previously prescribed, it is possible according to the present embodiment to provide the ignition device 1, which can achieve an improvement in fuel efficiency. (Second embodiment)

[0048] In the second embodiment, the ignition control device 5 contains, as in Fig. Figure 10 illustrates a filter unit 54. The filter unit 54 contains a high-frequency filter and converts a waveform of the pressure change within the main combustion chamber 3, which is obtained by the operating information acquisition unit 4, so that a specific waveform is derived. Subsequently, the knock determination unit 51 and the combustion noise determination unit 52 perform the corresponding determinations based on the specific waveform.

[0049] Furthermore, as in Fig. Figure 10 illustrates that in the second embodiment, a discharge energy control unit 531 and a discharge timing control unit 532 are provided instead of the ignition energy control unit 53 of the first embodiment. The discharge energy control unit 531 controls the discharge energy at the ignition coil 20. The discharge timing control unit 532 controls the ignition unit 23 at the ignition coil 20 to control the discharge timing. The ignition energy to be supplied to the spark plug 2 is controlled by the control of both the discharge energy and the ignition timing by means of the ignition energy control unit 531 and the discharge timing control unit 532. Other components are the same as in a case of the first embodiment, and therefore the same reference numerals as in the first embodiment are used in a case of the present embodiment, without the need to describe these parts.

[0050] In the second embodiment, the filter unit 54 converts the waveform, as shown in Fig. 11(a) to Fig. Figure 11(c) illustrates this. It should be noted that in the present embodiment, the filter unit 54 includes a 5 kHz high-pass filter. Fig. 11(a) to Fig. 11(c) all illustrate waveforms in relation to a pressure in the cylinder before and after conversion by the filter unit 54, wherein Fig. 11(a) illustrates a case of normal combustion, Fig. 11(b) illustrates a case in which the combustion noise occurs, and Fig. 11(c) illustrates a case in which the knocking occurs. As in Fig. As illustrated in Figure 11(a), in a case of normal combustion, the maximum value or peak of the waveform after filter conversion becomes extremely small. On the other hand, as shown in Fig. Figure 11(b) illustrates that, in a case where combustion noise occurs, a maximum of the waveform after filter conversion can be readily identified, with the peak exhibiting a bilateral symmetrical shape with a relatively rapid rise and fall. Furthermore, as shown in Fig. Figure 11(c) illustrates that, in a case where knocking occurs, a peak of the waveform can be readily identified after filter conversion, exhibiting a bilateral asymmetric shape with a rapid rise and a relatively gentle fall. In this way, the waveform conversion by the filter unit 54 can easily distinguish a case where combustion noise occurs from a case where knocking occurs, and from a case of normal combustion.

[0051] In the present embodiment, the operating information acquisition unit 4 detects the pressure change in the main combustion chamber 3, and the ignition control unit 5 controls the ignition energy profile based on the pressure change obtained by the operating information acquisition unit 4. This allows knocking or combustion noise to be detected in real time, thus improving robustness with respect to changes in the operating conditions. It should be noted that the second embodiment provides operational effects that are identical to those of the first embodiment.

[0052] It should be noted that the ignition energy in a third modified example, which is in Fig. Figure 12(a) illustrates that in a case where the ignition coil 20 contains a first ignition circuit 201 and a second ignition circuit 202, both connected in parallel, it can be controlled by switching to a circuit to be used. This is achieved by switching from a state in which the first coil circuit 201 and the second coil circuit 202 are energized to a state in which the first coil circuit 201 is not energized, as shown in Figure 12(a). Fig. As illustrated in Figure 12(b), the ignition energy can be reduced, whereas the ignition energy can be increased by switching the state to a state in which both circuits are excited.

[0053] Furthermore, the ignition energy can be increased in a fourth modified example, which is described in Fig. 13(a) illustrates a case in which ignition is carried out by the spark plug 2, which performs a discharge several times to sequentially supply discharge energy, by controlling the number of discharges such that the number of discharges, as in Fig. 13(a) illustrates, is reduced, can be reduced, whereby the ignition energy can be increased by controlling the number of times the discharge is performed, so that the number of times the discharge is performed, which is not illustrated.

[0054] Furthermore, in a fifth modified example, which is in Fig. Figure 13(b) illustrates the ignition energy by controlling a discharge current at spark plug 2, such that the discharge current, as in Fig. 13(b) illustrates, dampening, reducing, whereby the ignition energy can be increased by controlling the discharge current, so that the discharge current is amplified, which is not illustrated.

[0055] Furthermore, in a sixth modified example, which is in Fig. 13(c) illustrates the ignition energy by controlling a discharge period at spark plug 2, such that the discharge period of spark plug 2, as in Fig. 13(c) illustrates, is shortened, can be reduced, whereby the ignition energy can be increased by controlling the discharge period, so that the discharge period at spark plug 2, which is not illustrated, is prolonged.

[0056] Furthermore, in a seventh modified example, which is in Fig. Figure 13(d) illustrates that the ignition energy can be controlled by controlling the discharge time from the ignition coil 20 to the spark plug 2, such that the discharge time, as shown in Fig. 13(d) illustrates that it is delayed, will be reduced.

[0057] In all third to seventh modified examples described above, the same operational effects as in the first and second embodiments can be provided.

[0058] It should be noted that in the first embodiment described above, in a case where the load is in the second high-load range Sb, which is lower than the first high-load range Sa, which is the nominal load, the Fig.As illustrated in Figure 5(a), the energy supplied is increased in a case where the load belongs to a load range higher than the first high-load range Sa, while the energy supplied is decreased. With this control, in a case where it is determined that the knocking condition is met, the energy supplied to the spark plug is increased. However, in order to increase the energy supplied to the spark plug in a case where it is determined that the knocking condition is met, the control does not need to be carried out in conjunction with the control of the energy supplied to the spark plug in the high-load range in the first embodiment. The control of the energy supplied to the spark plug is simplified to a case where it is determined that the knocking condition is met.

[0059] The present disclosure is not limited to the embodiments and modified examples described above and can be applied to different embodiments within the scope that does not deviate from the spirit of the present disclosure.

[0060] Although the present disclosure has been described with reference to embodiments, it should be understood that the present disclosure is not limited to embodiments and structures. The present disclosure includes various modified examples and modifications within a range of equivalence. Furthermore, various combinations, embodiments, and other combinations and embodiments containing only one element or more or fewer elements fall within the scope and subject matter of the present disclosure.

Claims

[1] Ignition device (1) for internal combustion, the ignition device comprising: a spark plug (2) which contains an additional chamber (21) and an injection hole (22) from which a flame from the additional chamber is to be injected into a main combustion chamber (3); an operational information acquisition unit (4) configured to acquire operational information regarding an operating state of the internal combustion; and an ignition control unit (5) configured to control an ignition energy profile that influences an ignition state of an air-fuel mixture based on the operating information obtained by the operating information acquisition unit, wherein the ignition control unit is configured to: to compare a predetermined target load with a load obtained by the operational information acquisition unit, to reduce the ignition energy to be supplied to the spark plug in response to a comparison result indicating that the achieved load is higher than the target load, and to increase the ignition energy to be supplied to the spark plug in response to the comparison result indicating that the achieved load is lower than the target load. [2] Ignition device according to claim 1, wherein the ignition control unit is configured to: to determine whether the condition of the occurrence of knocking is met, and to increase the ignition energy to be supplied to the spark plug in response to the determination that the condition of knocking has been met. [3] Ignition device (1) for internal combustion, the ignition device comprising: a spark plug (2) which contains an additional chamber (21) and an injection hole (22) from which a flame from the additional chamber is to be injected into a main combustion chamber (3); an operational information acquisition unit (4) configured to acquire operational information regarding an operating state of the internal combustion; and an ignition control unit (5) configured to control an ignition energy profile that influences an ignition state of an air-fuel mixture based on the operating information obtained by the operating information acquisition unit, wherein the ignition control unit is configured to: to determine whether the condition of the occurrence of knocking is met, and to increase the ignition energy to be supplied to the spark plug in response to the determination that the condition of knocking has been met. [4] Ignition device according to any one of claims 1 to 3, wherein the ignition control unit is configured to: to determine whether the operating condition fulfills a condition for the occurrence of knocking, to determine whether, in response to determining that the knocking condition is met, it is possible to prevent knocking by increasing the ignition energy to be supplied to the spark plug, and the ignition timing in response to the determination that it is not possible to prevent or delay the knocking. [5] Ignition device (1) for internal combustion, the ignition device comprising: a spark plug (2) which contains an additional chamber (21) and an injection hole (22) from which a flame from the additional chamber is to be injected into a main combustion chamber (3); an operational information acquisition unit (4) configured to acquire operational information regarding an operating state of the internal combustion; and an ignition control unit (5) configured to control an ignition energy profile that influences an ignition state of an air-fuel mixture based on the operating information obtained by the operating information acquisition unit, wherein the ignition control unit is configured to: to determine whether the operating condition fulfills a condition for the occurrence of knocking, to determine whether, in response to determining that the knocking condition is met, it is possible to prevent knocking by increasing the ignition energy to be supplied to the spark plug, and the ignition timing in response to the determination that it is not possible to prevent or delay the knocking. [6] Ignition device according to any one of claims 1 to 5, wherein the ignition energy profile includes ignition energy to be supplied to the spark plug. [7] Ignition device according to any one of claims 1 to 6, wherein the operating information includes at least a load or a rotational speed during internal combustion. [8] Ignition device according to any one of claims 1 to 7, wherein the ignition control unit is configured to: to determine whether the pressure oscillation that occurs together with the injection of the flame from the injection hole fulfills a condition for the occurrence of a combustion noise, and to reduce the ignition energy to be supplied to the spark plug in response to the determination that the condition of the occurrence of combustion noise is met. [9] Ignition device according to any one of claims 1 to 8, wherein the operational information acquisition unit is configured to detect the pressure change of the main combustion chamber, and The ignition control unit is configured to control the ignition energy profile based on the pressure change obtained by the operating information acquisition unit.

Images