JP4349237B2 - Laser ignition device - Google Patents

Description

  The present invention relates to a laser ignition device that uses a laser to ignite a combustible air-fuel mixture introduced into a combustion chamber of an engine in a vehicle engine.

  Conventionally, a laser ignition device using a laser has been considered as an ignition device for a vehicle engine. In such a laser ignition device, the laser light emitted from the laser is condensed into a combustion chamber of the engine by a lens, and ignited and burned. At this time, as the number of focal points of the laser beam in the combustion chamber, that is, the number of ignition sources increases, the ignitability improves and the flame propagation speed after ignition improves. Thereby, it is considered that the efficiency of the engine can be increased.

Therefore, an ignition device that irradiates a plurality of laser beams into a combustion chamber and ignites at a plurality of ignition points has been proposed (see, for example, Patent Document 1). In this ignition device, a plurality of lasers are installed for each cylinder of the engine, and the number of ignitions is increased by irradiating and condensing laser light from each laser into the combustion chamber.
JP 55-81272 A

  However, in the above conventional technique, the number of ignitions is increased by installing a plurality of lasers for each cylinder of the engine, but the number of ignitions and ignition energy according to engine conditions are not controlled. Here, the engine condition refers to a parameter indicating an engine state such as an engine speed and a throttle opening / closing level.

  For this reason, for example, when the load on the engine is relatively low, that is, when the amount of intake air is small or the intake pipe pressure is low, increasing the number of ignitions in the combustion chamber improves the thermal efficiency by improving the flame propagation speed, Ignition energy required for ignition also increases. Therefore, useless ignition energy is consumed, and the total thermal efficiency of the engine may be reduced.

  Conversely, there is a possibility that ignition will not occur if the number of ignitions is small or the ignition energy per point is low when the load on the engine is high, that is, when the intake air amount is large or the intake pipe pressure is high.

  In view of the above points, the present invention can ignite an engine by directing and condensing a laser beam into a combustion chamber of a vehicle engine, so that the engine can be ignited according to engine conditions, and the total thermal efficiency of the engine is improved. An object of the present invention is to provide a laser ignition device capable of achieving the above.

In order to achieve the above object, according to the first aspect of the present invention, a laser that ignites a combustible mixture introduced into the combustion chamber by directing and condensing the laser beam to the combustion chamber (120) of the engine (100). An igniter that emits laser light (21, 31, 22, 32, 23) and laser light emitted by the laser light irradiation means are incident on the laser light. Laser light irradiation unit (10) that collects light at one or more points in the combustion chamber, detection means (50) for detecting engine conditions of the engine, and laser light irradiation based on the engine conditions detected by the detection means and control means for changing the ignition number in the combustion chamber by driving means and the laser beam irradiation unit (40), it has a first laser as the laser beam irradiation means (21, 31) and a second record In the laser beam irradiation unit, the laser beam irradiated from the first laser or the second laser is respectively incident on the laser beam irradiation unit. When the engine load is high, the control means irradiates laser beams from the first laser and the second laser, respectively, so as to increase the number of ignition than when the engine load is low, The laser beam irradiation means and the laser beam irradiation unit are driven, and when the engine load is low, the laser beam is irradiated from either the first laser or the second laser. It is characterized by.

  As described above, the engine condition is detected, and the ignition number is changed based on the engine condition. Thereby, the number of ignitions suitable for engine conditions can be changed. Specifically, when the engine is in a state where it is easy to drive, useless energy can be reduced by reducing the number of ignitions. Conversely, when the engine is difficult to drive, increasing the number of ignitions makes it easier to drive the engine, and smooth engine driving can be realized. Thus, by controlling the number of ignitions according to the engine conditions, it is possible to improve the total thermal efficiency of the engine and hence the fuel efficiency of the engine.

Further , the number of ignitions is increased or decreased according to the engine load. That is, by increasing the number of ignitions when the engine is high load than when the engine is low load, the flame propagation speed can be improved, and knocking can be avoided. Further, when the engine is under a low load, it is possible to ignite with the minimum ignition energy while ensuring the flame propagation speed by reducing the number of ignitions. Therefore, by increasing or decreasing the number of ignitions according to the engine load, the total thermal efficiency can be subtracted, and the fuel efficiency can be improved.

Further , the irradiation of the first laser and the second laser is controlled based on the engine load of the engine (for example, the opening / closing level of the throttle valve, the intake air amount, the pressure in the intake pipe) detected by the detection means. At this time, when the engine is heavily loaded, the first and second lasers are irradiated to increase the number of ignitions in the combustion chamber. Thereby, the flame propagation speed in a combustion chamber can be improved. On the other hand, when the engine is lightly loaded, the number of ignitions is reduced by irradiating either the first laser or the second laser. Thereby, since ignition is performed with a small number of ignitions, fuel consumption can be improved.

  As described above, the total thermal efficiency of the engine can be improved by detecting the engine load of the engine and increasing or decreasing the number of ignitions according to the level of the engine load.

According to a second aspect of the present invention, there is provided a laser ignition device for igniting a combustible air-fuel mixture introduced into a combustion chamber by guiding and condensing a laser beam to a combustion chamber (120) of an engine (100). Laser light irradiation means (21, 31, 22, 32, 23) for emitting light and laser light irradiated by the laser light irradiation means are incident, and the incident laser light is incident on the combustion chamber at one point or multiple points. The laser light irradiation unit (10) for condensing the light, the detection means (50) for detecting the engine condition of the engine, and the laser light irradiation means and the laser light irradiation unit based on the engine condition detected by the detection means a drive control unit (40), and having a first laser (21, 31) and a second laser as laser beam irradiating means (22, 32), the laser beam irradiation unit includes a first And laser light emitted from the laser or the second laser is adapted to be respectively incident, detection means is adapted to detect the ignitability in the combustion chamber based on the engine condition, also, the engine misfire A misfire detecting means for detecting, and the misfire detecting means detects at least one of an engine speed of the engine, an exhaust temperature in the exhaust pipe (162) of the engine, and a pressure in the intake pipe (152) of the engine. Detects and outputs signals corresponding to the detected engine speed, exhaust temperature in the exhaust pipe, and pressure in the intake pipe. When the ignitability is high , the control means is low. The laser light irradiation means and the laser light irradiation unit should be controlled so that the ignition energy is lower than that, the number of ignitions is reduced, or both are controlled. Adapted to moving, also the engine speed, exhaust temperature of the exhaust pipe, signal and inputs respectively corresponding to the pressure in the intake pipe, on the basis of these signals, the engine speed, exhaust temperature in the exhaust pipe, At least one value of the pressure in the intake pipe is obtained, and the obtained value is compared with a threshold value for judging misfire. If the obtained value exceeds the threshold value, the engine is misfired. It is characterized in that the number of ignitions in the combustion chamber is increased by irradiating the first laser and the second laser and determining that a misfiring has occurred in the engine by determining that it has occurred . .

  Thus, the ignition energy and the number of ignitions are controlled according to the ignitability in the combustion chamber of the engine. Thereby, when the ignitability is high, it is possible to ignite with the minimum energy by lowering the ignition energy or reducing the number of ignitions. On the other hand, when the ignitability is low, ignitability can be improved by increasing the ignition energy or increasing the number of ignitions, and smooth ignition can be performed. By performing ignition energy control according to such ignitability, the fuel efficiency of the engine can be improved.

In addition , the engine misfire is determined based on at least one of the change in physical quantity that occurs when the engine misfire occurs, that is, the engine speed, the exhaust temperature in the exhaust pipe, and the pressure in the intake pipe. When the misfire is detected, the ignition number is increased more than when the misfire is detected. As a result, the number of ignition points in the combustion chamber is increased to facilitate ignition. Therefore, engine misfire can be avoided.

In the invention according to claim 3 , when the control means determines that misfire has occurred in the engine, the control means irradiates with either one of the first laser and the second laser, or both of which is increased. The laser light irradiation means and the laser light irradiation unit are driven.

  Thus, when a misfire occurs in the engine, the laser intensity of one or both of the first laser and the second laser is increased. Thereby, the ignition energy at the ignition point can be increased, and the ignitability can be improved.

According to a fourth aspect of the present invention, the detection means comprises a water temperature detection means for detecting the coolant temperature of the engine and an intake pipe pressure detection means for detecting the pressure in the intake pipe of the engine, and these water temperature detection means And a signal corresponding to the water temperature detected by the intake pipe pressure detection means and the pressure in the intake pipe, respectively, and the control means outputs the ignition energy required for ignition according to the water temperature and the pressure in the intake pipe. It has a three-dimensional map to be derived, and inputs signals corresponding to the water temperature and the pressure in the intake pipe, and obtains the water temperature and the pressure in the intake pipe based on these signals, and the obtained water temperature and the pressure in the intake pipe By substituting each of the values into a three-dimensional map, the ignition energy is derived, and the first level is set so that the ignition energy at the ignition point in the combustion chamber becomes the calculated ignition energy. It is characterized that it is as the irradiating THE and second laser.

  In this way, the engine energy, that is, the coolant temperature of the engine and the pressure value in the intake pipe are substituted into the three-dimensional map to obtain the ignition energy necessary for ignition. This three-dimensional map is set such that the higher the coolant temperature of the engine and the pressure in the intake pipe, the lower the ignition energy, and the lower the coolant temperature of the engine and the pressure in the intake pipe, the higher the ignition energy. . Therefore, the higher the water temperature and the pressure in the intake pipe, the better the ignitability in the combustion chamber, so that the ignition energy required for ignition can be reduced. Similarly, the lower the water temperature and the pressure in the intake pipe, the worse the ignitability in the combustion chamber. Therefore, the ignition energy required for ignition can be increased to improve the ignitability.

  In this way, the fuel efficiency of the engine can be improved by performing the ignition energy control according to the state of the engine. The intake air temperature in the intake pipe may be used instead of the coolant temperature of the engine.

According to a fifth aspect of the present invention, there is provided a laser ignition device for igniting a combustible air-fuel mixture introduced into a combustion chamber by guiding and condensing laser light to a combustion chamber (120) of an engine (100). Laser light irradiation means (21, 31, 22, 32, 23) for emitting light and laser light irradiated by the laser light irradiation means are incident, and the incident laser light is incident on the combustion chamber at one point or multiple points. The laser light irradiation unit (10) for condensing the light, the detection means (50) for detecting the engine condition of the engine, and the laser light irradiation means and the laser light irradiation unit based on the engine condition detected by the detection means a drive control unit (40), and having a first laser (21, 31) and a second laser as laser beam irradiating means (22, 32), the laser beam irradiation unit includes a first Laser light emitted from the laser or the second laser is respectively incident, and the detection means includes engine speed detection means for detecting the engine speed of the engine and ignition on for detecting the ON state of the ignition switch. Detection means and ignition start detection means for detecting the start state of the ignition switch, the engine speed detection means outputs a signal corresponding to the engine speed of the engine, and the ignition on detection means A signal corresponding to the ON state is output, and the ignition start detecting means outputs a signal corresponding to the start state of the ignition switch, and the control means is at the start of the engine than when the engine is normally operated. Increase ignition energy Or increasing the ignition number, or to perform the control of both, being adapted to drive the laser light emitting device and a laser beam irradiation unit, also inputs a signal corresponding to the ON state from the ignition-on detecting means In addition, when the first laser and the second laser are put on standby and a signal corresponding to the start state is input from the ignition start detection means, the laser is irradiated from the first laser and the second laser, respectively, and the engine is started. A signal corresponding to the engine speed detected by the engine speed detecting means is input, and the engine speed is obtained based on this signal. If the obtained engine speed exceeds a predetermined engine speed, the engine speed is It is determined that the start is completed, and irradiation of one of the first laser and the second laser is stopped. It is characterized that it is so that.

  Thus, the ignition energy is increased when the engine is started. Thereby, the ignitability at the time of engine start can be improved, and a smooth engine start can be realized. Therefore, the engine can be started without wasting energy when starting the engine, and the fuel consumption can be improved.

Then , at the time of starting the engine, the first laser and the second laser are kept on standby, and the irradiation of the first laser or the second laser is stopped after the engine is started. Thereby, when starting the engine, it is possible to increase the number of ignitions, that is, the number of ignition points, by irradiating the first and second lasers, thereby facilitating ignition. Therefore, the startability of the engine can be improved.

  Further, as described above, after the engine is started, irradiation of one of the first and second lasers is stopped. Thereby, since the number of ignition is reduced compared with the time of engine starting, a fuel consumption can be improved. Note that it may be determined whether or not the engine has been started by determining whether or not a predetermined time has elapsed after the engine is started.

In the invention according to claim 6 , when the control means determines that the engine start has not been completed, the control means determines whether or not a predetermined time estimated to have ended the engine start has elapsed, and the predetermined time has elapsed. , It is characterized in that the laser light intensity of both or either one of the first laser and the second laser is increased.

  As described above, after the engine is started, if it is determined that the engine has not been started even after a predetermined time estimated to have been completed, the number of ignitions in the combustion chamber is increased and ignition is performed. Is done. Thereby, ignitability can be improved and the engine can be easily started.

According to a seventh aspect of the present invention, there is provided a laser ignition device for igniting a combustible air-fuel mixture introduced into a combustion chamber by guiding and condensing a laser beam to a combustion chamber (120) of an engine (100). Laser light irradiation means (21, 31, 22, 32, 23) for emitting light and laser light irradiated by the laser light irradiation means are incident, and the incident laser light is incident on the combustion chamber at one point or multiple points. The laser light irradiation unit (10) for condensing the light, the detection means (50) for detecting the engine condition of the engine, and the laser light irradiation means and the laser light irradiation unit based on the engine condition detected by the detection means a drive control unit (40), and having a first laser (21, 31) and a second laser as laser beam irradiating means (22, 32), the laser beam irradiation unit includes a first Laser light emitted from the laser or the second laser is respectively incident, and the detection means includes engine speed detection means for detecting the engine speed of the engine and ignition on for detecting the ON state of the ignition switch. Detection means and ignition start detection means for detecting the start state of the ignition switch, the engine speed detection means outputs a signal corresponding to the engine speed of the engine, and the ignition on detection means A signal corresponding to the ON state is output, the ignition start detecting means outputs a signal corresponding to the start state of the ignition switch, and the laser beam irradiation unit outputs a plurality of laser beams irradiated from the first laser. The second lens leads to the combustion chamber The compound eye lens (18) has an optical path changing mirror (61-63) for changing the optical path of the laser light emitted from the first laser, and the laser light guided through the optical path changing mirror is focused on the combustion chamber. And a control means for controlling the ignition energy to be higher at the time of starting the engine and / or to increase the number of ignition than at the time of normal operation of the engine. In addition, the laser light irradiation means and the laser light irradiation unit are driven, and when a signal corresponding to the ON state is input from the ignition ON detection means, the first laser is put on standby and the laser light irradiation unit is driven. An optical path changing mirror is arranged on the optical path of the laser light of the first laser to guide the laser light emitted from the first laser to the monocular lens. After that, when a start signal is input from the engine start detection means, laser light is emitted from the first laser, and the laser light is condensed from the monocular lens via the optical path changing mirror to ignite and start the engine. Thereafter, a signal corresponding to the engine speed detected by the engine speed detecting means is inputted, and the engine speed is obtained based on this signal. When the obtained engine speed exceeds a predetermined engine speed, It is determined that the engine has been started, the laser beam irradiation unit is driven, the optical path changing mirror is removed from the optical path of the laser beam of the first laser, and the laser beam irradiated from the first laser is guided to the first compound eye lens. It is characterized by becoming.

Thus , the ignition energy is increased when the engine is started. This makes the engine
It can improve the ignitability at the start, and can realize a smooth engine start
The Therefore, start the engine without wasting energy when starting the engine.
Fuel efficiency can be improved. The laser light emitted from the first laser is guided to the combustion chamber as a plurality of focal points by the first compound eye lens, and when starting the engine, the laser light is transmitted to the monocular lens by the optical path changing mirror. Lead to. The ignition energy at the ignition point is increased by setting the focal point of the laser beam to one, that is, one ignition point, regardless of the magnitude of the engine load. As a result, the ignitability can be improved when the engine is started, and the engine startability can be improved.

  Note that the lens that guides the laser light emitted from the second laser to the combustion chamber may be a compound eye lens, and the laser light of the second laser may be guided to the monocular lens by the optical path changing mirror when the engine is started.

  After the engine is started, the number of ignitions is increased by guiding the laser light emitted from the first laser 21 to the first compound eye lens, and the flame propagation speed is improved while suppressing the energy required for ignition. Total thermal efficiency can be improved.

In the invention according to claim 8, when it is determined that the engine start is not completed, the control means determines whether or not a predetermined time estimated to have ended the engine start has elapsed, and the predetermined time has elapsed. Is determined, the laser beam irradiation unit is driven and the optical path changing mirror is arranged on the optical path of the laser beam of the first laser and the laser beam is guided to the monocular lens, or both of the first laser and the second laser are selected. One of the features is that the intensity of one of the laser beams is increased.

  As described above, after the engine is started, if it is determined that the engine has not been started even after a predetermined time estimated to have been completed, the number of ignitions in the combustion chamber is increased and ignition is performed. Or ignited at one ignition point. Thereby, ignitability can be improved and the engine can be easily started.

According to the ninth aspect of the present invention, there is provided a laser ignition device for igniting a combustible air-fuel mixture introduced into a combustion chamber by guiding and condensing a laser beam to a combustion chamber (120) of an engine (100). Laser light irradiation means (21, 31, 22, 32, 23) for emitting light and laser light irradiated by the laser light irradiation means are incident, and the incident laser light is incident on the combustion chamber at one point or multiple points. The laser light irradiation unit (10) for condensing the light, the detection means (50) for detecting the engine condition of the engine, and the laser light irradiation means and the laser light irradiation unit based on the engine condition detected by the detection means control means for changing the ignition number in the combustion chamber by driving (40), has a has a first laser (21, 31) and a second laser as laser beam irradiating means (22, 32) In the laser light irradiation unit, the laser light emitted from the first laser or the second laser is respectively incident, and the detection means includes knocking detection means for detecting knocking of the engine. The knocking detection means detects engine vibration and outputs a signal corresponding to the vibration . When the engine knocking is detected , the control means detects the number of ignitions before the knocking is detected. The laser light irradiation means and the laser light irradiation unit are driven so as to increase the frequency, and it has a knocking frequency band indicating knocking of the engine. When the vibration frequency of the engine is determined based on the signal corresponding to the vibration and the calculated frequency is included in the knocking frequency band Determines that knocking has occurred in the engine, and by irradiating the first laser and the second laser, the number of ignitions in the combustion chamber is increased more than when it is determined that knocking has occurred in the engine. It is characterized in that there.

  Thus, the number of ignitions is changed according to engine knocking. Thereby, when engine knocking occurs, knocking can be avoided by increasing the number of ignitions. Such control can improve the fuel consumption of the engine.

Further , when engine knocking is detected and it is determined that the engine is knocking, the ignition number is increased more than when knocking is detected. Thereby, a flame propagation speed can be improved. For this reason, it is possible to avoid an abnormal pressure increase in the combustion chamber that occurs when knocking occurs, and thus knocking can be avoided.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. Although not limited, the laser ignition device according to the present embodiment is applied to, for example, a port injection engine or an in-cylinder direct engine.

  FIG. 1 is a schematic block diagram of a laser ignition device according to a first embodiment of the present invention. As shown in FIG. 1, the laser ignition device includes a laser irradiation unit 10, a first laser 21, a second laser 22, a first driver 31, a second driver 32, an engine ECU 40, and a sensor unit 50. And is configured.

  The laser irradiation unit 10 is installed in a cylinder head 110 of the engine 100 and guides laser light emitted from first and second lasers 21 and 22 described later to a combustion chamber 120 of the engine 100. Such a laser irradiation unit 10 includes a first mirror 11, a second mirror 12, a case 13, a first biconcave lens 14, a second biconcave lens 15, a first plano-convex lens 16, and a second plano-convex lens. 17, a first compound eye lens 18, and a second compound eye lens 19.

  The first and second mirrors 11 and 12 guide laser light emitted from the first and second lasers 21 and 22 into the case 13. The case 13 has a cylindrical shape, and is provided with first and second biconcave lenses 14 and 15 on one end side of the case 13, and the first and second plano-convex lenses 16 and 17 are accommodated inside the case 13. First and second compound eye lenses 18 and 19 are provided on the other end side of the lens.

  The first and second biconcave lenses 14 and 15 are lenses that radiate and emit incident light. The first and second plano-convex lenses 16 and 17 are lenses that collect incident light and emit it as parallel waves. The first and second compound eye lenses 18 and 19 respectively include a plurality of lenses having different focal positions, and guide incident light to different focal positions. This focal point becomes an ignition point (ignition point) in the combustion chamber 120.

  FIG. 2 shows how the laser beams emitted from the first and second lasers 21 and 22 are divided and collected by the first and second compound eye lenses 18 and 19 as described above. FIG. 2 is a view of the cylinder head 110 viewed from the piston 140 that reciprocates within the cylinder 130 of the engine 100. In FIG. 2, the intake valve 151 and the exhaust valve 161 are omitted.

  As shown in FIG. 2, each of the first and second compound lenses 18, 19 is formed with four lenses, and the focal position of each lens is arranged at an arbitrary position in the combustion chamber 120. It has become. Specifically, those focal points are located on the circumference of a circle CI having a predetermined diameter. Therefore, for example, even when only the laser beam from the first laser 21 is guided to the combustion chamber 120, the four focal points of the first compound eye lens 18 are arranged on the circumference of the circle CI. The ignition point is not biased. The same applies to the second laser 22. The above is the configuration of the laser irradiation unit 10.

  In the laser irradiation unit 10 having such a configuration, the other end side of the case 13 is integrated with the cylinder head 110 of the engine 100 as shown in FIG.

  The laser light emitted from the first laser 21 is reflected by the first mirror 11 and guided to one end side of the case 13, enters the first biconcave lens 14, diverges, and the first plano-convex lens. 16 is converted into a parallel wave again, enters the first compound eye lens 18, and is divided into four different places in the combustion chamber 120 and collected.

  Similarly, the laser light emitted from the second laser 22 is reflected by the second mirror 12 and guided to one end side of the case 13, enters the second biconcave lens 15, diverges, and second flattened. The convex lens 17 makes it a parallel wave again, enters the second compound eye lens 19, and is divided and condensed at four different locations in the combustion chamber 120, specifically at positions other than the focal position of the first compound eye lens 18. . In this way, the laser beam is applied to the combustion chamber 120.

  The first and second lasers 21 and 22 are known laser light sources that emit laser light. The laser beams emitted from the first and second lasers 21 and 22 are guided to the first and second mirrors 11 and 12 of the laser irradiation unit 10, respectively.

  The first and second drivers 31 and 32 are placed on standby so that the first and second lasers 21 and 22 can be irradiated, and the laser beams are irradiated from the respective lasers 21 and 22. Specifically, when the first and second drivers 31 and 32 receive the laser light irradiation signal input from the engine ECU 40, the laser light is emitted at the laser light irradiation timing (that is, the ignition timing) based on the laser light irradiation signal. Is irradiated with laser light from each of the lasers 21 and 22.

  The first laser 21 and the first driver 31 may be combined to form the first laser 21. In other words, the first driver 31 may be built in the first laser 21. Similarly, the second laser 22 and the second driver 32 may be combined to form the second laser 22. Moreover, the 1st laser 21, the 1st driver 31, the 2nd laser 22, and the 2nd driver 32 are equivalent to the laser beam irradiation means of this invention.

  The engine ECU 40 controls the number of ignitions and ignition energy in the combustion chamber 120 according to the state of the engine 100, and is a known microcomputer provided with a CPU, a memory, and the like. Such an engine ECU 40 controls the number of ignitions at the start of the vehicle, controls the number of ignitions according to the engine load, controls the number of ignitions according to misfire of the combustion chamber 120, controls the number of ignitions for knocking, The ignition energy is controlled accordingly. These controls will be described in detail later. The engine ECU 40 corresponds to the control means of the present invention.

  The sensor unit 50 is a sensor group that detects an engine state. Such a sensor unit 50 includes an ignition sensor, an intake pipe pressure sensor, an engine speed sensor, a throttle sensor, an intake intake air amount sensor, a knock sensor, a water temperature sensor, an oil temperature sensor, and an intake pipe temperature. A sensor and an exhaust pipe temperature sensor are provided. Each of these sensor groups is installed at a desired position, and signals detected by the respective sensors are output to the engine ECU 40, respectively. The sensor unit 50 corresponds to the detection means of the present invention.

  The ignition sensor is a sensor that monitors whether an ignition switch of the vehicle is on or off. When the key is inserted into the key cylinder and the ignition switch is turned on by turning the key, an on signal is output to the engine ECU 40. Similarly, when the ignition switch is started, a start signal is output to the engine ECU 40.

  Thus, it can be said that the ignition sensor includes ignition-on detection means for detecting the on-state of the ignition switch and ignition start detection means for detecting the start-up state of the ignition switch.

  The intake pipe pressure sensor is a known pressure sensor that detects the internal pressure of the intake pipe 152 of the engine 100. In such a pressure sensor, the pressure of the pressure medium (intake air) is detected by a sensor chip having a thin diaphragm as a pressure detection unit, and an electric signal at a level corresponding to the pressure is output to the engine ECU 40. The engine ECU 40 obtains the pressure inside the intake pipe 152 by converting an electric signal input from the intake pipe pressure sensor into a pressure value. The intake pipe pressure sensor corresponds to the intake pipe pressure detecting means of the present invention.

  The engine speed sensor is a known sensor that detects the engine speed of the engine 100. Such an engine speed sensor generates a pulse signal corresponding to, for example, the rotation of a ring gear (or a rotor or the like) and outputs the pulse signal to the engine ECU 40. Then, the engine ECU 40 obtains the engine speed by converting the pulse signal input from the engine speed sensor into the engine speed. The engine speed sensor corresponds to the engine speed detecting means of the present invention.

  The throttle sensor is provided inside the intake pipe 152 and detects the opening / closing level of a throttle valve that adjusts the amount of air (air mixture) fed into the combustion chamber 120. A signal indicating the opening / closing level of the throttle valve detected by the throttle sensor is output to the engine ECU 40.

  The intake air intake amount sensor is a sensor that detects the amount of air sucked into the intake pipe 152, and is installed in the intake pipe 152. In this intake air intake amount sensor, the intake air amount is detected based on the flow rate of air flowing through the intake pipe 152 and output to the engine ECU 40.

  The knock sensor is a sensor that detects knocking (premature ignition) of engine 100, and includes a vibrating body and a piezoelectric element that converts vibration of the vibrating body into an electrical signal. When knocking occurs while the engine 100 is operating, the vibration body of the knock sensor vibrates at a characteristic frequency corresponding to the knocking.

  That is, the knock sensor detects the vibration of engine 100 and outputs an electrical signal corresponding to the vibration to engine ECU 40. And engine ECU40 inputs an electrical signal from the said knock sensor, and converts it into a frequency. The engine ECU 40 stores a knocking frequency band representing knocking in advance, and monitors whether the frequency obtained by the knock sensor is included in the knocking frequency band stored in advance. The knock sensor corresponds to the knocking detection means of the present invention.

  The water temperature sensor is a temperature sensor that measures the temperature of the cooling water that cools the engine 100, and is installed at a desired position in the cooling water path. The oil temperature sensor detects the temperature of oil for lubricating each component inside the engine 100. Signals detected by the water temperature sensor and the oil temperature sensor are output to the engine ECU 40, and the engine ECU 40 converts them into water temperature and oil temperature. These water temperature and oil temperature sensors are constituted by a thermistor, for example. The water temperature sensor corresponds to the water temperature detecting means of the present invention.

  The exhaust pipe temperature sensor measures the temperature in the exhaust pipe 162 of the engine 100, and is a well-known temperature sensor composed of, for example, a thermistor. These exhaust pipe temperature sensors are installed in the exhaust pipe 162 so that the temperature detection part is exposed in the exhaust pipe 162 of the engine 100. A signal detected by the exhaust pipe temperature sensor is output to the engine ECU 40 and converted into a temperature by the engine ECU 40. The exhaust pipe temperature sensor, the engine speed sensor, and the intake pipe pressure sensor correspond to the misfire detection means of the present invention.

  The above is the configuration of the laser ignition device according to the present embodiment. In addition, the said structure is prepared for every cylinder except the component which can be made common to one engine 100, such as engine ECU40, a knock sensor, a water temperature sensor. Next, control of the number of ignitions and control of ignition energy performed by the engine ECU 40 of the laser ignition device will be described.

  First, control of the number of ignitions when engine 100 is started will be described. When the engine 100 is started, the ignitability is improved by increasing the number of ignitions in the combustion chamber 120, and the engine 100 is started smoothly. This will be described with reference to FIG. FIG. 3 is a flowchart showing the contents of control of the number of ignitions when engine 100 is started. This flowchart is started when power is supplied to the engine ECU 40.

  In step S100, it is determined whether or not an ignition switch (hereinafter referred to as IG) is turned on. That is, it is determined whether or not the IG is turned on when the passenger inserts the key into the key cylinder and turns the key. This is done by determining whether an ON signal output from the ignition switch is input to the engine ECU 40.

  If the IG on signal is input to engine ECU 40 and it is determined that IG is on, the process proceeds to step S110. If the IG on signal is not input, the process returns to step S100 to determine again whether or not the IG on signal is input.

  In step S110, preparations for irradiation of the first laser 21 and the second laser 22 are made. That is, the first and second drivers 31 and 32 are operated so that the first and second lasers 21 and 22 can emit laser light.

  In step S120, it is determined whether or not IG is started. That is, it is determined whether the key is turned and IG is set to “START (ST)”. This is done by determining whether or not a start signal is input from the IG to the engine ECU 40.

  If it is determined that the IG start signal is input to the engine ECU 40, the process proceeds to step S130. On the other hand, when the IG start signal is not input to the engine ECU 40, the process returns to step S120, and it is determined again whether the IG is started.

  In step S130, engine 100 is started. Specifically, laser light irradiation signals for irradiating laser light from the first and second lasers 21 and 22 are output from the engine ECU 40 to the first and second drivers 31 and 32. Laser light is emitted from the first and second lasers 21 and 22 by the first and second drivers 31 and 32 to which the laser light irradiation signal is input.

  In this manner, the laser beams are emitted from the first and second lasers 21 and 22, respectively, and the number of ignitions in the combustion chamber 120 is increased to make it easier to start the engine.

  In step S140, it is determined whether the engine has been started. That is, in this step, after engine 100 is started in step S130, it is determined whether or not the engine speed has reached a predetermined speed. That is, the engine 100 is started, and after a while, the engine speed becomes constant and the engine 100 operates stably. Therefore, the engine 100 is started by monitoring the engine speed detected by the engine speed sensor. It can be determined whether or not it has been completed. Therefore, when the engine speed reaches the predetermined speed, it is determined that the engine 100 has been started, and the process proceeds to step S150. On the other hand, when the engine speed does not reach the predetermined speed, the process returns to step S130 and the engine 100 is started.

  In this step, it is determined whether or not the engine 100 has been started by monitoring the engine speed. However, after the engine 100 is started in step S130, the engine 100 is started after a predetermined time. It may be determined that is completed.

  In step S150, the irradiation of the second laser 22 is stopped. Since it is determined in step S140 that the engine 100 has been started, a large number of ignitions for starting the engine 100 are not necessary. Accordingly, the laser light irradiation of the second laser 22 out of the first and second lasers 21 and 22 is stopped. This is because a signal to stop the second laser 22 is output from the engine ECU 40 to the second driver 32, and the laser light irradiation of the second laser 22 is stopped by the second driver 32 to which this signal is input. Is made by The first laser 21 may be stopped from irradiation.

  As described above, the number of ignitions when the engine 100 is started, that is, the number of ignition points is increased. In this way, the startability of the engine 100 is improved.

  Next, control of the number of ignitions or ignition energy after engine 100 is started will be described.

  First, an operation for changing the number of ignitions according to the load on engine 100 and increasing the output of engine 100 will be described. Therefore, the load on the engine 100 will be described. In the engine 100, the intake air is sent from the intake pipe 152 to the combustion chamber 120 via the intake valve 151. At this time, the load on engine 100 increases as the pressure in intake pipe 152 and the intake air intake amount increase.

  Here, FIG. 4 shows the relationship between the number of ignitions and the flame propagation speed, and the relationship between the number of ignitions and the required ignition energy. The required ignition energy refers to energy required for ignition.

  Regarding the relationship between the number of ignitions and the flame propagation speed, when the number of ignitions is 1 to 4, the flame propagation speed increases rapidly, and when the number of ignitions exceeds 4, it becomes almost constant. On the other hand, in the relationship between the number of ignitions and the required ignition energy, the energy required for ignition increases as the number of ignitions increases. That is, when the load on the engine 100 is low or medium, fuel efficiency is improved by setting the number of ignitions (3 to 5 points) at a high flame propagation speed even if the required ignition energy is low. On the other hand, when the load of the engine 100 is high, the energy required for ignition is high, but a high flame propagation speed is ensured to increase the thermal efficiency, thereby avoiding knocking.

  Hereinafter, the control of the number of ignitions will be described with reference to FIG. FIG. 5 is a flowchart showing the contents of ignition number control by the load of engine 100. This flowchart is executed after the flowchart shown in FIG.

  In step S200, the load of engine 100 is calculated. Specifically, a signal from the throttle sensor of the sensor unit 50 is input to the engine ECU 40. In the present embodiment, the opening / closing level of the throttle sensor is regarded as the load level of the engine 100, and the load of the engine 100 is maximum when the value of the throttle sensor is maximum (the throttle valve is fully open). . The throttle sensor detects the opening / closing level of the throttle valve, and the signal is input to the engine ECU 40.

  The load on engine 100 is calculated based on the intake air amount detected by the intake air amount sensor and the pressure value in intake pipe 152 detected by the intake pipe pressure sensor. May be.

  In step S210, it is determined whether or not engine 100 has a high load. This is determined based on the value of the throttle sensor detected in step S200. That is, when the state where the throttle valve is fully opened is 100%, the value when the throttle valve is opened 50% is set as the threshold value. If the value detected by the throttle sensor exceeds this threshold value (the throttle valve is opened by 50% or more), the process proceeds to step S220. On the other hand, if the value detected by the throttle sensor does not exceed the threshold value, the process returns to step S200, and the load of the engine 100 is calculated again.

  In step S220, the number of ignitions is increased. That is, the number of ignitions is increased by applying ignition by the second laser 22 to a state in which only the first laser 21 is ignited. This is done by outputting a laser light irradiation signal from the engine ECU 40 to the second driver 32 and irradiating the second laser 22 with the laser light by the second driver.

  When the number of ignitions is increased in step S220, the process returns to step S200 again, and the flowchart shown in FIG. 5 is repeated. In the present embodiment, the number of ignitions is increased, for example, for a predetermined time in step S220, and the ignition is returned to only the first laser 21 again.

  Thus, the number of ignitions is changed according to the load state of the engine 100, and the engine 100 is operated with the number of ignitions that matches the load of the engine 100. That is, when the engine load is high, the number of ignitions is increased and the flame propagation speed is improved compared to when the engine load is low.

  Next, control of the number of ignitions when misfire occurs in the combustion chamber 120 will be described with reference to FIGS. 6 and 7. FIG. 6 is a flowchart showing the contents of ignition number control according to misfire in the combustion chamber 120. This flowchart is executed after the flowchart shown in FIG. 3 is completed, and is executed in parallel with the flowchart shown in FIG.

  In step S300, engine misfire is detected. That is, when the engine 100 is operating, a parameter representing the operating state of the engine 100 is detected. Specifically, signals indicating the engine speed, the exhaust temperature in the exhaust pipe 162, and the pressure in the intake pipe 152 are detected by the engine speed sensor, the exhaust pipe temperature sensor, and the intake pipe pressure sensor of the sensor unit 50, respectively. Each is converted into a numerical value by the engine ECU 40.

  In step S310, it is determined whether a misfire has occurred. That is, it is determined whether or not misfire has occurred based on the engine speed of engine 100 detected in step S300, the exhaust temperature in exhaust pipe 162, and the pressure value in intake pipe 152. FIG. 7 is a graph in which the engine speed, the exhaust temperature in the exhaust pipe 162, and the pressure in the intake pipe 152 are plotted with respect to time. 7A shows the engine speed with respect to time, FIG. 7B shows the exhaust temperature in the exhaust pipe 162 with respect to time, and FIG. 7C shows the pressure in the intake pipe 152 with respect to time.

  Misfire is determined as follows. As shown in FIG. 7 (a), the engine speed that has been output stably decreases temporarily due to misfire, and returns to the original stable value again. Therefore, a threshold value is provided for the engine speed, and it is determined that a misfire has occurred when the engine speed exceeds this threshold value.

  Similarly, as shown in FIG. 7B, the exhaust temperature in the exhaust pipe 162 oscillates at a predetermined cycle. However, when misfire occurs, the cycle collapses. Therefore, a desired threshold value is provided for the exhaust temperature in the exhaust pipe 162, the timing at which the exhaust temperature exceeds the threshold value is measured, and it is determined that a misfire has occurred if the timing is incorrect.

  Furthermore, as shown in FIG. 7C, the stable pressure in the intake pipe 152 temporarily increases due to misfire. Therefore, a threshold is provided for the pressure in the intake pipe 152, and when the pressure in the intake pipe 152 exceeds this threshold, it is determined that a misfire has occurred.

  Such misfire is determined based on any one of the above-described FIGS. 7 (a) to 7 (c). In the present embodiment, misfire is determined by monitoring the engine speed. In addition, you may make it determine misfire based on all the parameters shown by Fig.7 (a)-(c). In this case, misfire can be determined more reliably.

  If it is determined that a misfire has occurred, the process proceeds to step S320. On the other hand, if it is determined that no misfire has occurred, the process returns to step S300 again, and engine misfire is detected.

  In step S320, the number of ignitions is increased. In this step, processing similar to that in step S220 shown in FIG. 5 is performed. Thus, when the number of ignitions accompanying the misfire of the engine 100 is controlled, the process returns to step S300 again, the engine state is detected, and the misfire is monitored.

  As described above, when misfire occurs in the engine 100, the number of ignitions is increased to promote combustion in the combustion chamber 120, and misfire is avoided.

  Next, ignition number control for knocking of engine 100 will be described with reference to FIG. FIG. 8 is a flowchart showing the contents of ignition number control for knocking of engine 100. This flowchart is executed after the flowchart shown in FIG. 3 is completed, and is executed in parallel with the flowcharts shown in FIGS. 5 and 6.

  In step S400, the knocking state of engine 100 is detected. Specifically, a signal detected by the knock sensor of sensor unit 50 is input to engine ECU 40, and the vibration frequency of engine 100 detected by the knock sensor is obtained.

  In step S410, it is determined whether knocking has occurred. That is, it is determined whether or not the vibration frequency of engine 100 obtained in step S400 is included in a knocking frequency band representing knocking stored in advance in engine ECU 40. If it is determined that the vibration of engine 100 obtained by the knock sensor is the vibration of knocking, the process proceeds to step S420. On the other hand, when it is determined that the vibration of engine 100 obtained by the knock sensor does not correspond to the vibration of knocking, the process returns to step S400, and the knocking state is detected again.

  In step S420, the number of ignitions is increased. In this step, processing similar to that in step S220 shown in FIG. 5 is performed. Thus, when the number of ignitions associated with knocking of engine 100 is controlled, the process returns to step S400 again, and the knocking state is detected.

  As described above, knocking of engine 100 is avoided by performing ignition number control in accordance with knocking of engine 100.

  Subsequently, the control of the ignition energy according to the state of the engine 100 will be described. As described above, when the engine 100 is operated by controlling the number of ignitions, ignition energy necessary for ignition is calculated, and ignition without wasteful ignition energy is performed.

  Here, the state of the engine 100 refers to the temperature of the engine 100 (the temperature of the coolant of the engine 100 or the temperature in the intake pipe 152) and the pressure in the engine 100 (pressure in the intake pipe 152). That is, as the water temperature of the engine 100, the intake air temperature, and the pressure in the intake pipe 152 are higher, the ignitability in the combustion chamber 120 is improved, so that the ignition energy required for ignition can be reduced. In the present embodiment, the state of the engine 100 is monitored by the temperature of the engine coolant and the pressure in the intake pipe 152.

  The calculation of the ignition energy will be described with reference to FIG. 9 and FIG. FIG. 9 is a flowchart showing the details of ignition energy control in accordance with the state of engine 100. This flowchart is executed after the flowchart shown in FIG. 3 is completed, and is executed in parallel with the flowcharts shown in FIGS. 5, 6, and 8, and the ignition energy calculated by this flowchart corresponds to the number of ignitions. Adopted during control.

  In step S500, the state of engine 100 is detected. That is, a signal corresponding to the water temperature of the cooling water that cools engine 100 is detected by the water temperature sensor. A signal corresponding to the pressure in the intake pipe 152 is detected by the intake pipe pressure sensor. These signals are output to the engine ECU 40 and converted into the coolant temperature and the pressure in the intake pipe 152, respectively.

  In step S510, ignition energy required for ignition is calculated based on the coolant temperature obtained in step S500 and the pressure in the intake pipe 152. This will be described with reference to FIG. FIG. 10 is a diagram showing a three-dimensional map of necessary ignition energy. As described above, the higher the water temperature of the engine 100 and the pressure in the intake pipe 152, the higher the ignitability and the lower the ignition energy required for ignition. Therefore, as shown in the three-dimensional map of FIG. 10, the required ignition energy decreases as the cooling water temperature (T) of the engine 100 increases and the pressure (P) in the intake pipe 152 increases. Conversely, the lower the water temperature (T) of the engine 100 and the pressure (P) in the intake pipe 152, the worse the ignitability in the engine 100, so that the required ignition energy increases.

  Thus, the required ignition energy corresponding to the water temperature (T) of the engine 100 and the pressure (P) in the intake pipe 152 is calculated in advance and stored in the engine ECU 40 as a three-dimensional map shown in FIG. deep. In this step, the necessary ignition from the three-dimensional map shown in FIG. 10 using the coolant temperature (T) of the cooling water of the engine 100 and the pressure (P) in the intake pipe 152 obtained in step S500. Find the energy (E).

  In step S520, the ignition energy is changed. Specifically, the engine ECU 40 causes the first or second driver 31, 32 to change the intensity of the laser light of the first and second lasers 21, 22. In this way, the optimum ignition energy is obtained.

  When changing the ignition energy, for example, the ignition energy may be changed by changing the intensity of one of the laser beams, such as only the first laser 21 or only the second laser 22.

  After changing the ignition energy, the process returns to step S500 again, the state of the engine 100 is measured, and the ignition energy is changed according to the state of the engine 100 as needed. As described above, the ignition energy control according to the state of the engine 100 is performed to improve the fuel consumption of the engine 100.

  Note that the ignition number control and ignition energy control shown in FIGS. 3, 5, 6, 8, and 9 may be performed in combination, or any one of them may be performed. Also good.

  As described above, in the present embodiment, the number of ignitions and the ignition energy are controlled according to the state of the engine, that is, the load applied to the engine 100 and the time when the engine 100 is started.

  As described above, when the load on the engine 100 (the opening / closing level of the throttle valve in the engine 100, the intake air amount, the pressure in the intake pipe) is high, the first and second lasers 21 and 22 are irradiated to the combustion chamber By increasing the number of ignitions at 120, the flame propagation speed in the combustion chamber 120 can be improved. Thereby, knocking can also be prevented. On the other hand, when the load of the engine 100 is low, fuel efficiency can be improved by irradiating one of the first and second lasers 21 and 22 to reduce the number of ignitions. As described above, the total thermal efficiency of the engine 100 can be improved by changing the number of ignitions according to the load on the engine 100.

  Further, when the engine 100 misfires, the number of ignitions is increased. As a result, the number of ignition points in the combustion chamber 120 is increased to facilitate ignition. Thereby, misfire of engine 100 can be avoided. Similarly, when it is determined that the engine 100 is knocking, the flame propagation speed can be improved by increasing the number of ignitions. Thereby, knocking of engine 100 can be prevented.

  Furthermore, in this embodiment, the ignition energy is controlled. That is, by substituting the coolant temperature of engine 100 and the pressure value in intake pipe 152 into the three-dimensional map shown in FIG. 10, ignition energy required for ignition can be obtained. Thereby, when the water temperature and the pressure in the intake pipe 152 are high, the ignitability in the combustion chamber 120 is improved, so that the ignition energy necessary for ignition can be reduced. Similarly, when the water temperature and the pressure in the intake pipe are low, the ignitability in the combustion chamber 120 is deteriorated, so that the ignition energy required for ignition can be increased to improve the ignitability. Thus, by performing the ignition energy control according to the state of the engine 100, the thermal efficiency of the engine 100 can be increased and the fuel efficiency can be improved.

  Further, the number of ignitions is controlled when the engine 100 is started. That is, when the engine 100 is started, the first and second lasers 21 and 22 are irradiated to increase the number of ignitions, that is, the number of ignition points, so that ignition can be facilitated. In this way, the startability of engine 100 can be improved. After the engine 100 is started, fuel consumption can be improved by reducing the number of ignitions in the combustion chamber 120 by stopping the irradiation of the second laser 22.

(Second Embodiment)
In the present embodiment, only different parts from the first embodiment will be described. In the present embodiment, when the engine 100 is started, the engine is operated regardless of the magnitude of the engine load. That is, the ignition point is concentrated on one point to increase the ignition energy per one ignition point.

  FIG. 11 is a schematic block diagram of a laser ignition device according to the second embodiment. As shown in FIG. 11, in addition to the configuration in the first embodiment, the laser ignition device includes a starting point fire mirror 61 to 63, a third plano-convex lens 65, and a fourth plano-convex lens 67. Has been. These start time fire mirrors 61 to 63 and the third and fourth plano-convex lenses 65 and 67 are used only when the engine 100 is started. In FIG. 11, the second laser 22, the first and second mirrors 11 and 12 are omitted.

  The start-time fire mirrors 61 to 63 are mirrors for guiding the laser light of the first laser 21 to the third plano-convex lens 65 in the case 13 when the engine 100 is started. These starting point fire mirrors 61 to 63 are provided in the laser irradiation unit 10 and are provided with driving means such as a motor (not shown). This driving means is driven by the engine ECU 40. Thereby, the arrangement position of the starting point fire mirrors 61 to 63 is changed. The starting-time fire mirrors 61 to 63 correspond to the optical path changing mirror of the present invention.

  In other words, the start-time fire mirrors 61 to 63 are inserted between the first laser 21 and the first mirror 11 when the engine 100 is started, so that the laser light emitted from the first laser 21 is irradiated to the case 13. It guides to the 3rd plano-convex lens 65 inside.

  Note that the laser beam emitted from the second laser 22 may be guided to the third and fourth plano-convex lenses 65 and 67 by the start-time fire mirrors 61 to 63.

  The third and fourth plano-convex lenses 65 and 67 are arranged in the case 13 of the laser irradiation unit 10 and guide the laser light of the first laser 21 guided from the starting point fire mirrors 61 to 63 to the combustion chamber 120. It is. Here, the third plano-convex lens 65 is disposed on one end side of the case 13, and the fourth plano-convex lens 67 is disposed on the other end side of the case 13.

  FIG. 12 is a view of the cylinder head 110 viewed from the piston 140 that reciprocates within the cylinder 130 of the engine 100. In FIG. 12, the intake valve 151 and the exhaust valve 161 are omitted. As shown in FIG. 12, in addition to the first and second compound eye lenses 18 and 19, a fourth plano-convex lens 67 is installed on the other end side of the case 13. Since the fourth plano-convex lens 67 is a monocular lens having one focal point, the laser light emitted from the first laser 21 is condensed at one point by the fourth plano-convex lens 67.

  In the laser ignition device having the above-described configuration, ignition energy control when the engine 100 is started will be described with reference to FIG. FIG. 13 is a flowchart showing the contents of ignition energy control when engine 100 is started. This flowchart is started when power is supplied to the engine ECU 40.

  In step S600, it is determined whether or not IG is turned on. In this step, processing similar to that in step S100 shown in FIG. 3 is performed.

  In step S610, preparation for irradiation with the first laser 21 is made. That is, the first driver 31 is put on standby so that laser light can be emitted from the first laser 21.

  In step S620, start time fire mirrors 61-63 are arranged. Specifically, in the laser irradiation unit 10, the starting point fire mirrors 61 to 63 are moved by the driving means provided in the starting point fire mirrors 61 to 63, and the laser light emitted from the first laser 21 is emitted. Guide to the third plano-convex lens 65.

  Here, ignition energy at the time of starting engine 100 is determined from the engine state. This will be described with reference to FIG. FIG. 14 is a diagram showing the relationship between the coolant temperature of engine 100 and the starting point fire energy. As described above, when the engine 100 is cold, the ignitability at the time of ignition is poor, and ignition energy is also required. Therefore, the engine ECU 40 calculates ignition energy necessary for starting the engine 100 from the coolant temperature of the engine 100, and enables ignition with the calculated ignition energy.

  In step S630, it is determined whether engine 100 has been started. In this step, the same processing as step S120 shown in FIG. 3 is performed.

  In step S640, engine 100 is started. Specifically, a laser light irradiation signal is output from the engine ECU 40 to the first driver 31, and the first driver 21 emits laser light from the first laser 21. At this time, the laser beam irradiated from the first laser 21 is irradiated into the combustion chamber 120 via the starting point fire mirrors 61 to 63 and the third and fourth plano-convex lenses 65 and 67. Then, the laser light is condensed at one point by the fourth plano-convex lens 67, and the laser light is concentrated at one point. Thereby, the ignition energy at the focal point of the fourth plano-convex lens 67 is increased to improve the ignitability.

  Note that the intensity of the laser beam irradiated in this step is a value corresponding to the ignition energy obtained in step S620.

  In step S650, it is determined whether the engine has been started. In this step, processing similar to that in step S140 shown in FIG. 3 is performed.

  In step S660, the starting-time fire mirrors 61 to 63 are moved. That is, since ignition at the start of engine 100 has been completed, high ignition energy is not required for ignition. Accordingly, the engine ECU 40 drives the driving means provided in the starting point fire mirrors 61 to 63, and the starting point fire mirrors 61 to 63 are removed from the optical path of the laser light of the first laser 21. As a result, the laser beam of the first laser 21 is irradiated onto the first mirror 11 and normal ignition is performed.

  As described above, the ignition energy at the start of the engine 100, that is, the ignition energy per ignition point, is increased to facilitate the start of the engine 100. In this way, the ignitability at the start of the engine 100 is improved.

  That is, when the engine 100 is started, the ignition energy per ignition point is increased to facilitate ignition regardless of the load of the engine 100. Thus, the startability of the engine 100 is improved.

  As described above, in the present embodiment, when the engine 100 is started, the laser light emitted from the first laser 21 is guided to the fourth plano-convex lens 67 by the start time fire mirrors 61 to 63. Thereby, the ignition point in the combustion chamber 120, that is, the ignition point is set to one, and the ignition energy at one ignition point can be increased. Therefore, when the engine 100 is started, the ignitability at the ignition point can be improved, and the startability of the engine 100 can be improved.

(Third embodiment)
In the present embodiment, only parts different from the first and second embodiments will be described. In the present embodiment, when the engine 100 is started, the ignition energy when the starting time exceeds a certain time is controlled. That is, this is ignition energy control for dealing with a case where ignition is performed in the combustion chamber 120 to start the engine 100 but not ignition. The laser ignition device according to the present embodiment is the same as the configuration of the laser ignition device according to the first and second embodiments.

  FIG. 15 is a flowchart showing the contents of ignition energy control when the starting time of engine 100 exceeds a certain time. This flowchart is started when power is supplied to the engine ECU 40.

  In steps S700, S710, and S720, the same processing as in steps S100, S610, and S120 described above is performed.

  In step S730, engine 100 is started. In the present embodiment, the engine 100 is started only by the first laser 21. That is, the laser light irradiation signal is output from the engine ECU 40 to the first driver 31, and the first driver 21 to which the laser light irradiation signal is input is irradiated with the laser light from the first laser 21. Thereby, combustion is started by being ignited in the combustion chamber 120.

  In step S740, it is determined whether the engine has been started. In this step, processing similar to that in step S140 shown in FIG. 3 is performed. In this step, if it is determined that the engine has been started, it is determined that the engine 100 has started normally, and the flowchart ends. On the other hand, if it is determined that the engine start is not completed, the process proceeds to step S750.

  In step S750, it is determined whether a predetermined time has elapsed after the engine is started. Here, the predetermined time corresponds to a time estimated to have started the engine 100 and is, for example, 1 second. If it is determined that a predetermined time has elapsed after the engine is started, the process proceeds to step S760. On the other hand, if it is determined that the predetermined time has not elapsed after the engine is started, the process returns to step S730 again and the engine 100 is started.

  In step S760, the ignition energy is increased. Specifically, the process of step S620 is performed, and the number of focal points of the laser light irradiated to the combustion chamber 120 is set to one, and the ignition energy per ignition point is increased. Thus, the ignitability is improved and the engine 100 is easily started.

  In step S770, it is determined whether the engine has been started. In this step, processing similar to that in step S740 is performed. If it is determined in this step that the engine start is not completed, the process returns to step S760 to further increase the ignition energy. Note that further increases in ignition energy include, for example, increasing the intensity of laser light emitted from the first laser 21 and irradiating the second laser 22. By these methods, the ignition energy is increased to make it easier to start the engine 100.

  On the other hand, if it is determined that the engine has been started, it is determined that engine 100 has started normally, and the flowchart ends.

  As described above, it is determined whether the engine 100 has started normally based on the engine speed and elapsed time since the engine 100 was started. If the engine 100 does not start normally, ignition energy is increased and ignition is performed. This improves the startability of the engine 100.

  As described above, in the present embodiment, after starting the engine 100, when it is determined that the engine 100 does not start even after the estimated time that the engine 100 has started, the control for increasing the ignition energy is performed. Has been made. Thus, the ignitability can be improved by increasing the ignition energy at the ignition point in the combustion chamber 120. Therefore, engine 100 can be easily started.

(Other embodiments)
The configuration of the laser ignition device shown in the first to third embodiments is merely an example, and is not limited to the above configuration. For example, control with only one laser is possible, and three or more lasers may be controlled. Similarly, each flowchart of the ignition number control and ignition energy control shown in the first to third embodiments is an example, and each control is not limited to the flowchart.

  In the first to third embodiments, the focal points of the first and second compound lenses 18 and 19 are arranged so as to be located on the circumference of the circle CI as shown in FIG. The position of is not limited to the circumference of the circle CI.

  In the said 1st Embodiment, in order to change ignition energy, the intensity | strength of each laser beam of the 1st laser 21 and the 2nd laser 22 was changed. However, for example, when changing the ignition energy, as shown in FIG. 11, the laser beam emitted from the first laser 21 is condensed at one point so as to increase the ignition energy per ignition point. Also good.

  In step S220 (FIG. 5), step S320 (FIG. 6), and step S420 (FIG. 8) of the first embodiment, the pressure in the intake pipe 152, the temperature in the intake pipe 152, the oil temperature or water temperature of the engine 100, The number of ignitions may be changed based on the engine speed. FIG. 16 is a diagram showing a map for changing the number of ignitions. 16A shows the relationship between the intake air temperature in the intake pipe 152 and the pressure in the intake pipe 152. FIG. 16B shows the relationship between the oil temperature or water temperature of the engine 100 and the pressure in the intake pipe 152. FIG. (C) is a diagram showing the relationship between the engine speed and the pressure in the intake pipe 152, respectively.

  In this way, the ignition number change map shown in FIG. 16 is stored in advance in the engine ECU 40, and the engine state (in FIG. 16, the pressure in the intake pipe 152, the intake temperature in the intake pipe 152, the engine 100). The oil temperature or water temperature, and the engine speed) may be measured by sensors, and the ignition number may be changed based on the measured values.

  In step S110 (FIG. 3) of the first embodiment, preparations for irradiation with laser beams from the first and second lasers 21 and 22 are made. Here, although not shown, two mirrors (one is a half mirror) are prepared, and laser light emitted from the second laser 22 is irradiated with laser light emitted from the first laser 21 via the two mirrors. It is also possible to increase the ignition energy per point by superimposing them on. After the engine 100 is started, the two mirrors are removed in step S150 (FIG. 3).

  In the first to third embodiments, two lasers of the first and second lasers 21 and 22 are used, but the number of ignitions can be controlled by one laser. FIG. 17 is a schematic block diagram showing how the number of ignitions is controlled by the third laser 23 which is a laser beam irradiation means. As shown in FIG. 17, the laser light emitted from the third laser 23 is guided to the second and third mirrors 12 and 72 by the half mirror 71, and the laser light reflected by the third mirror 72 is the first. Guide to the mirror 11. The number of ignitions in the combustion chamber 120 can be changed by moving the half mirror 71 with, for example, a motor.

  Four lenses are formed in each of the first and second compound lenses 18 and 19 employed in the first to third embodiments, but the number of lenses is not limited to this. For example, a first compound eye lens 18 in which three lenses are formed and a second compound eye lens 19 in which five lenses are formed may be used. FIG. 18 is a view of the cylinder head 110 side from the piston 140 side when the first and second compound eye lenses 18 and 19 having different numbers of lenses are installed in the case 13. As shown in this figure, the focal positions do not overlap even if the number of lenses is different. Thus, the number of lenses formed in the first and second compound eye lenses 18 and 19 may be arbitrarily changed. Of course, the focal point of the lens does not have to be positioned on the circumference of a circle having a predetermined diameter.

  The steps shown in each figure correspond to means for executing various processes.

1 is a schematic block diagram of a laser ignition device according to a first embodiment of the present invention. It is the figure which looked at the cylinder head side from the piston side in FIG. It is the flowchart which showed the control content of the ignition number at the time of engine starting. It is the figure which showed the relationship between the number of ignitions and a flame propagation speed, and the relationship between the number of ignitions and required ignition energy. It is a flowchart showing the content of the ignition number control by the engine load. It is a flowchart showing the content of ignition number control according to misfire in a combustion chamber. It is the figure which plotted the engine speed, the exhaust temperature in an exhaust pipe, and the pressure in an intake pipe with respect to time, respectively. It is a flowchart showing the content of ignition number control with respect to knocking of an engine. It is a flowchart showing the control content of the ignition energy according to an engine state. It is the figure which showed the three-dimensional map of required ignition energy. It is a schematic block diagram of the laser ignition device which concerns on 2nd Embodiment. In FIG. 11, it is the figure which looked at the cylinder head side from the piston side which reciprocates within the cylinder of an engine. It is a flowchart showing the contents of ignition energy control at the time of engine start. It is the figure which showed the relationship between the water temperature of engine cooling water, and a starting time fire energy. It is a flowchart showing the contents of ignition energy control when the engine start time exceeds a certain time. It is the figure which showed the change map of the ignition number. It is the schematic block diagram which showed a mode that the number of ignitions was controlled with a 3rd laser. It is the figure which looked at the cylinder head side from the piston side, when the 1st and 2nd compound eye lens from which the number of lenses each differs is installed in the case.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Laser irradiation unit, 11 ... 1st mirror, 12 ... 2nd mirror, 13 ... Case,
14 ... 1st biconcave lens, 15 ... 2nd biconcave lens, 16 ... 1st plano-convex lens,
17 ... 2nd plano-convex lens, 18 ... 1st compound eye lens, 19 ... 2nd compound eye lens,
21 ... 1st laser, 22 ... 2nd laser, 23 ... 3rd laser,
31 ... 1st driver, 32 ... 2nd driver, 40 ... Engine ECU, 50 ... Sensor part,
61-63 ... Start-up fire mirror, 65 ... Third plano-convex lens, 67 ... Fourth plano-convex lens,
71 ... half mirror, 72 ... third mirror,
DESCRIPTION OF SYMBOLS 100 ... Engine, 110 ... Cylinder head, 120 ... Combustion chamber, 130 ... Cylinder,
140 ... Piston, CI ... Yen.

Claims (9)

A laser ignition device that ignites a combustible air-fuel mixture introduced into the combustion chamber by guiding and condensing laser light to a combustion chamber (120) of the engine (100),
Laser light irradiation means (21, 31, 22, 32, 23) for emitting the laser light;
A laser beam irradiation unit (10) for receiving the laser beam irradiated by the laser beam irradiation means and condensing the incident laser beam in the combustion chamber at one point or multiple points;
Detection means (50) for detecting engine conditions of the engine;
On the basis of the detected engine condition by the detecting means, we have a, and control means for changing the ignition number (40) in the combustion chamber by driving the laser beam irradiation means and the laser beam irradiation unit,
As the laser beam irradiation means, the first laser (21, 31) and the second laser (22, 32),
In the laser beam irradiation unit, laser beams irradiated from the first laser or the second laser are respectively incident.
The detection means is adapted to detect an engine load as the engine condition,
When the engine load is high, the control means irradiates laser light from the first laser and the second laser, respectively, and increases the number of ignitions as compared with the case where the engine load is low. And the laser beam irradiation unit are driven, and when the engine load is low, the laser beam is irradiated from either one of the first laser and the second laser. A laser ignition device characterized by that. A laser ignition device that ignites a combustible air-fuel mixture introduced into the combustion chamber by guiding and condensing laser light to a combustion chamber (120) of the engine (100),
Laser light irradiation means (21, 31, 22, 32, 23) for emitting the laser light;
A laser beam irradiation unit (10) for receiving the laser beam irradiated by the laser beam irradiation means and condensing the incident laser beam in the combustion chamber at one point or multiple points;
Detection means (50) for detecting engine conditions of the engine;
Control means (40) for driving the laser light irradiation means and the laser light irradiation unit based on the engine condition detected by the detection means;
As the laser beam irradiation means, the first laser (21, 31) and the second laser (22, 32),
In the laser beam irradiation unit, laser beams irradiated from the first laser or the second laser are respectively incident.
The detection means detects ignitability in the combustion chamber based on the engine condition, and further comprises misfire detection means for detecting misfire of the engine, and the misfire detection means includes an engine of the engine. At least one of the rotational speed, the exhaust temperature in the exhaust pipe (162) of the engine, and the pressure in the intake pipe (152) of the engine is detected, and the detected engine rotational speed and the exhaust in the exhaust pipe are detected. A signal is output according to the temperature and the pressure in the intake pipe.
When the ignitability is high, the control means lowers the ignition energy than the case where the ignitability is low, or reduces the number of ignitions, or performs both of the control, The laser light irradiation unit is driven, and inputs signals corresponding to the engine speed, the exhaust temperature in the exhaust pipe, and the pressure in the intake pipe, and based on these signals, At least one value of engine speed, exhaust temperature in the exhaust pipe, and pressure in the intake pipe is obtained, and the obtained value is compared with a threshold value for determining the misfire, and the obtained value is If the threshold is exceeded, it is determined that a misfire has occurred in the engine, and the engine is lost by irradiating the first laser and the second laser. The laser ignition device, characterized in that is adapted to increase the ignition number in the combustion chamber than when is determined to be going on. When the control means determines that misfire has occurred in the engine, the laser light irradiation means is configured to increase the laser light intensity of one or both of the first laser and the second laser. The laser ignition device according to claim 2 , wherein the laser light irradiation unit is driven. The detection means includes a water temperature detection means for detecting the coolant temperature of the engine and an intake pipe pressure detection means for detecting a pressure in the intake pipe of the engine, and these water temperature detection means and intake pipe pressure detection A signal corresponding to the water temperature detected by each means and the pressure in the intake pipe is output,
The control means has a three-dimensional map for guiding ignition energy required for ignition in accordance with the water temperature and the pressure in the intake pipe, and inputs signals corresponding to the water temperature and the pressure in the intake pipe, respectively. Then, based on these signals, the water temperature and the pressure in the intake pipe are obtained, and the obtained water temperature and the pressure in the intake pipe are substituted into the three-dimensional map to derive ignition energy, and the ignition in the combustion chamber is obtained. as ignition energy of the point becomes a ignition energy obtained, laser ignition device according to claim 2 or 3, characterized in that is adapted to irradiate the first laser and the second laser. A laser ignition device that ignites a combustible air-fuel mixture introduced into the combustion chamber by guiding and condensing laser light to a combustion chamber (120) of the engine (100),
Laser light irradiation means (21, 31, 22, 32, 23) for emitting the laser light;
A laser beam irradiation unit (10) for receiving the laser beam irradiated by the laser beam irradiation means and condensing the incident laser beam in the combustion chamber at one point or multiple points;
Detection means (50) for detecting engine conditions of the engine;
Control means (40) for driving the laser light irradiation means and the laser light irradiation unit based on the engine condition detected by the detection means;
As the laser beam irradiation means, the first laser (21, 31) and the second laser (22, 32),
In the laser beam irradiation unit, laser beams irradiated from the first laser or the second laser are respectively incident.
The detecting means includes engine speed detecting means for detecting the engine speed of the engine, ignition on detecting means for detecting an on state of an ignition switch, and ignition start detecting means for detecting a start state of the ignition switch. Prepared,
The engine speed detection means outputs a signal according to the engine speed of the engine, the ignition on detection means outputs a signal according to the ON state of the ignition switch, and the ignition start detection means A signal corresponding to the start state of the ignition switch is output,
When the engine is started, the control means performs control of the laser light irradiation means and the laser so that the ignition energy is higher than that when the engine is normally operated or the number of ignitions is increased, or both. The light irradiation unit is driven, and a signal corresponding to the on state is input from the ignition on detection means, and the first laser and the second laser are set on standby, and the ignition start detection means When a signal corresponding to the start state is input, the engine is started by irradiating laser light from the first laser and the second laser, and then the engine speed detected by the engine speed detecting means is detected. A signal corresponding to the number is input, and based on this signal, the engine speed When the calculated engine speed exceeds the predetermined engine speed, it is determined that the engine has been started, and irradiation of one of the first laser and the second laser is stopped. a laser ignition device, characterized in that are. When the control means determines that the start of the engine is not completed, the control means determines whether or not a predetermined time estimated to have ended the start of the engine has elapsed, and determines that the predetermined time has elapsed, 6. The laser ignition device according to claim 5 , wherein the laser light intensity is increased by irradiating both or any one of the first laser and the second laser. A laser ignition device that ignites a combustible air-fuel mixture introduced into the combustion chamber by guiding and condensing laser light to a combustion chamber (120) of the engine (100),
Laser light irradiation means (21, 31, 22, 32, 23) for emitting the laser light;
A laser beam irradiation unit (10) for receiving the laser beam irradiated by the laser beam irradiation means and condensing the incident laser beam in the combustion chamber at one point or multiple points;
Detection means (50) for detecting engine conditions of the engine;
Control means (40) for driving the laser light irradiation means and the laser light irradiation unit based on the engine condition detected by the detection means;
As the laser beam irradiation means, the first laser (21, 31) and the second laser (22, 32),
In the laser beam irradiation unit, laser beams irradiated from the first laser or the second laser are respectively incident.
The detecting means includes engine speed detecting means for detecting the engine speed of the engine, ignition on detecting means for detecting an on state of an ignition switch, and ignition start detecting means for detecting a start state of the ignition switch. Prepared,
The engine speed detection means outputs a signal according to the engine speed of the engine, the ignition on detection means outputs a signal according to the ON state of the ignition switch, and the ignition start detection means A signal corresponding to the start state of the ignition switch is output,
The laser light irradiation unit includes a first compound eye lens (18) that guides laser light emitted from the first laser to the combustion chamber using a plurality of lenses.
An optical path changing mirror (61-63) that changes the optical path of the laser light emitted from the first laser, and a monocular lens that guides the laser light guided through the optical path changing mirror to the combustion chamber as one focal point ( 67)
When the engine is started, the control means performs control of the laser light irradiation means and the laser so that the ignition energy is higher than that when the engine is normally operated or the number of ignitions is increased, or both. The light irradiation unit is driven, and when a signal corresponding to the ON state is input from the ignition ON detection means, the first laser is put on standby, and the laser light irradiation unit is driven to drive the first laser light irradiation unit. When the optical path changing mirror is arranged on the optical path of the laser beam of the laser so that the laser light emitted from the first laser is guided to the monocular lens, the start signal is input from the engine start detection means. Laser light is emitted from the first laser, and the laser light is emitted from the monocular lens via the optical path changing mirror. The light is condensed and ignited and the engine is started. Thereafter, a signal corresponding to the engine speed detected by the engine speed detecting means is input, and the engine speed is obtained based on the signal. When the determined engine speed exceeds a predetermined engine speed, it is determined that the engine has been started, and the laser beam irradiation unit is driven to move the optical path changing mirror to the laser beam of the first laser. A laser ignition device characterized in that the laser light emitted from the first laser is guided to the first compound eye lens from the optical path . When the control means determines that the start of the engine is not completed, the control means determines whether or not a predetermined time estimated to have ended the start of the engine has elapsed, and determines that the predetermined time has elapsed, Drive the laser beam irradiation unit to place the optical path changing mirror on the optical path of the laser beam of the first laser and guide the laser beam to the monocular lens, or both the first laser and the second laser The laser ignition device according to claim 7 , wherein either one of the laser light intensities is increased for irradiation. A laser ignition device that ignites a combustible air-fuel mixture introduced into the combustion chamber by guiding and condensing laser light to a combustion chamber (120) of the engine (100),
Laser light irradiation means (21, 31, 22, 32, 23) for emitting the laser light;
A laser beam irradiation unit (10) for receiving the laser beam irradiated by the laser beam irradiation means and condensing the incident laser beam in the combustion chamber at one point or multiple points;
Detection means (50) for detecting engine conditions of the engine;
Control means (40) for changing the number of ignitions in the combustion chamber by driving the laser light irradiation means and the laser light irradiation unit based on the engine condition detected by the detection means;
As the laser beam irradiation means, the first laser (21, 31) and the second laser (22, 32),
In the laser beam irradiation unit, laser beams irradiated from the first laser or the second laser are respectively incident.
The detection means includes knock detection means for detecting knocking of the engine, and the knock detection means detects vibration of the engine and outputs a signal corresponding to the vibration.
When the engine knocking is detected, the control means drives the laser light irradiation means and the laser light irradiation unit so as to increase the number of ignitions than before the knocking is detected , The engine has a knocking frequency band indicating knocking of the engine, inputs a signal corresponding to the vibration, obtains a frequency of vibration of the engine based on the signal corresponding to the vibration, and the obtained frequency is When it is included in the knocking frequency band, it is determined that knocking has occurred in the engine, and by irradiating the first laser and the second laser, it is determined that knocking has occurred in the engine. Also, the number of ignitions in the combustion chamber is increased .

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