JPH03117641A - Alcohol engine - Google Patents

Abstract

PURPOSE:To improve fuel consumption by a method wherein, during partial load running, a communicating hole between a main combustion chamber and an auxiliary chamber is closed by means of an on-off valve to inject alcohol fuel in the main combustion chamber through a multihole injection nozzle and during total load running, the communicating hole is opened to inject alcohol fuel in the auxiliary chamber. CONSTITUTION:In a control device 10, when a partial load is detected by a load sensor 16, a communicating hole 14 between an auxiliary chamber 5 and a main combustion chamber 8 is closed by means of an on-off valve 6, a compression ratio is improved, and alcohol fuel through a multihole injection nozzle 15 is sprayed in the main combustion chamber 8 in a state to energize a glow plug 12. Meanwhile, when a total load is detected, the on-off valve 6 is opened, during a compression stroke, and intake air is forced to effect a squish inflow to the auxiliary chamber 5. Before a piston is moved to a top dead center, alcohol fuel is injected through a throttle nozzle 17 to produce excellent fuel-air mixture, and flame formed by natural ignition is discharged in the main combustion chamber 8. This constitution improves ignitability, and prevents the generation of unburnt gas, e.g. aldehyde.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an alcohol engine equipped with an on-off valve in a communication hole between a main combustion chamber and an auxiliary chamber.

[Conventional technology]

Conventionally, a variable compression ratio internal combustion engine including a valve in a communication hole between a main combustion chamber and a sub-combustion chamber is disclosed in Jitsuma@57-164224, for example. The variable compression ratio internal combustion engine has a combustion chamber of the internal combustion engine communicated with an auxiliary combustion chamber through a third valve, and the third valve is driven by a variable valve timing mechanism to remain closed in a low load range, Combustion is performed at a high compression ratio, and in a high load range, a cam-based valve mechanism is activated to open the engine from the middle of the compression process to the latter half of the exhaust process, and combustion is performed at a low compression ratio.

In addition, the opening and closing operations of the engine's intake and exhaust valves are driven by a mechanical valve mechanism such as a camshaft, but instead of this mechanical valve mechanism, an electric mechanism using suction force such as a solenoid is used. The technical idea that drives the valve is, for example,
JP-A-58-183305, JP-A-61-767
It is disclosed in Publication No. 13.

[Problem to be solved by the invention]

Incidentally, environmental pollution caused by exhaust gas emitted from engines has become a problem, and alcohol engines have recently been attracting attention. In an alcohol engine, the content of carbon dioxide gas and carbide in the exhaust gas is extremely small compared to fuels such as gasoline and diesel oil. However, diesel engines that use alcohol fuel have the problem of poor ignition performance. In other words, alcohol has a higher latent heat of vaporization than gasoline (for example, gasoline requires 0.7% of the latent heat of vaporization of fuel, whereas alcohol requires 5% of the latent heat of vaporization of fuel). This is because alcohol fuel has the property of being difficult to vaporize.Moreover, the alcohol fuel injected from the fuel injection nozzle into the compressed air in the combustion chamber is vaporized into the compressed air and the wall surface of the combustion chamber. This reduces the temperature of the fuel and worsens ignition.

By the way, in an adiabatic engine that has a combustion chamber with an adiabatic structure, the compressed air temperature at the end of the compression process is higher than that of a cooled engine, so if fuel is injected into that atmosphere, the vaporization of the fuel will be better. It will be held on.

However, for adiabatic engines that use alcohol as fuel, combustion at partial load is extremely different from combustion at full load; combustion is unstable at partial load, and the mixture formation speed is low at full load. There is a problem with delays. In particular, for compression ignition type reciprocating engines, normal direct injection engines have a compression ratio of 15 to
17 is said to be good. In this case, the compression end temperature is 65
When the temperature is around 0 degrees Celsius, ignition and combustion may not be good at startup or in low-temperature air, resulting in ignition errors and incomplete combustion, making it easier to generate unburned gas, and causing odor due to the discharge of unburned gas. , a pungent odor may occur.

Furthermore, at high loads, the fuel flow rate is 1.6 times or more compared to light oil, so it is very difficult to mix gas and liquid, resulting in a problem that the diffusion combustion period becomes long.

In particular, when the fuel is alcohol, the latent heat for vaporization is high, so when the engine is running at low speed and under low load, the wall surface of the combustion chamber is not in a high temperature state, so the wall surface absorbs the heat of vaporization from the fuel. , unable to promote vaporization,
It is difficult to successfully vaporize the air-fuel mixture, resulting in incomplete combustion and the phenomenon of unburned gas generation.

The purpose of this invention is to solve the above problems,
Alcohol fuel has a property that it has a large latent heat of vaporization compared to fuels such as gasoline and diesel oil, and the phenomenon that the temperature of the combustion chamber wall is low and the vaporization speed on the wall is slow is particularly noticeable when the engine is partially loaded. Taking this into consideration, the combustion chamber is divided into the main combustion chamber and the auxiliary chamber, and an on-off valve is placed in the communication hole that communicates the main combustion chamber and the auxiliary chamber, and the on-off valve is closed when the engine is under low load. In particular, when the engine is under high load, the on-off valve is kept open to reduce the compression ratio.
A single-hole throttle nozzle is placed in the auxiliary chamber to achieve stratified combustion and speed up diffusion combustion, and a multi-hole nozzle is placed in the main combustion chamber to create an air-fuel mixture using the spray energy of the nozzle. Furthermore, the opening/closing valve, the wall forming the auxiliary chamber, and the valve guide integrated with the wall are manufactured from a ceramic material with a small coefficient of linear expansion and excellent wear resistance. To provide an alcohol engine that can improve the durability of a guide, ensure good combustion, and prevent the generation of unburned gas.

[Means to solve the problem]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention provides an opening/closing valve that opens and closes a communication hole that communicates a main combustion chamber equipped with a multi-hole nozzle with an auxiliary chamber equipped with a throttle nozzle, a load sensor that detects engine load, and a portion using the load sensor. In response to a load signal, the on-off valve closes the communication hole to spray alcohol fuel from the multi-nozzle nozzle, and in response to a full load signal, the on-off valve opens the communication hole to control the throttle. The present invention relates to an alcohol engine that includes a controller that controls the injection of alcohol fuel from a nozzle.

Further, in this alcohol engine, the opening/closing valve is manufactured from a ceramic material, and the wall that constitutes the auxiliary chamber and has a valve guide on an upper part and a valve seat on a lower part on a concentric axis is manufactured in an integral structure from a ceramic material. This is what I did.

Furthermore, in this alcohol engine, a glow plug is arranged in the main combustion chamber.

[Effect]

The alcohol engine according to the present invention is constructed as described above and operates as follows. That is, in response to a partial load signal from a load sensor that detects engine load, this alcohol engine closes a communication hole between a main combustion chamber and an auxiliary chamber with an opening/closing valve, and a multi-nozzle disposed in the main combustion chamber. The communication hole is opened in response to a high load signal, and alcohol fuel is injected from a throttle nozzle disposed in the auxiliary chamber, so that when the engine is partially loaded, the alcohol fuel is sprayed from the auxiliary chamber. Since there is plenty of surplus air in the main combustion chamber, a good mixture is generated by the spray energy of the multi-hole nozzle, and mixture generation is achieved in a short time. Ensure good combustion and improve fuel efficiency.

Further, when the engine is under full load, the opening/closing valve is maintained in an open state to open the subchamber to perform combustion at a low compression ratio. That is, at full load, by switching to the pre-chamber type combustion system, a single hole mixing zone is created by the throttle nozzle in the swirl in the pre-chamber, and then secondary mixing is performed between air and atomized fuel by reverse squish. This will realize stratified combustion using single pores and increase the speed of diffusive combustion. Moreover, at full load, combustion is active and the temperature inside the main combustion chamber becomes high, promoting the vaporization of the alcohol fuel. However, if the fuel is completely burned in the auxiliary chamber, the output cannot be controlled, so the compression process At the top dead center T, D, C from the throttle nozzle where the flow of air and fuel flowing from the communication hole into the auxiliary chamber is large.

306, the mixture is quickly generated and ignited by mixing with the alcohol fuel injected before 306, a part of the fuel is combusted, and then the flame is reversely squirted from the auxiliary chamber to the main combustion chamber. The fuel is blown out and secondary mixing is performed to achieve complete combustion, and the fuel equivalence ratio is rapidly lowered, the combustion temperature is lowered, and the generation of NOx is suppressed.

[Embodiments] Hereinafter, embodiments of the alcohol engine according to the present invention will be described with reference to the drawings.

In FIG. 1, one embodiment of an alcohol engine according to the invention is shown. This alcohol engine
It has a main combustion chamber 8 and an auxiliary chamber 5 arranged above the supranuclear combustion chamber 8. The wall 22 constituting the sub-chamber 5 has a communication hole 14 that communicates the main combustion chamber 8 and the sub-chamber 5, a valve seat 9 in the communication hole 14, and a valve that guides the vertical movement of the opening/closing valve 6. The guide 21 has an integral structure. The on-off valve 6, the wall body 22, and the valve guide 21 are
Materials with a small coefficient of linear expansion and excellent wear resistance, such as
It is made of ceramic materials such as silicon nitride (SiJ4), silicon carbide (SiC), or composite ceramic materials. Valve seat 9 formed in this communication hole 14
An on-off valve 6 is provided. The communication hole 14 is located in the lower central part of the sub-chamber 5, and the valve stem 19 of the on-off valve 6 passes through the central part of the sub-chamber 5, and the valve stem 19 is integrally formed in the upper central part of the wall body 22. The opening/closing operation is guided by a guide 21. By the vertical movement of the on-off valve 22, the on-off valve 6 maintains the communication hole 14 in an open state or a closed state, and has the function of putting the main combustion chamber 8 and the sub-chamber 5 in a communicating state or a cutoff state. Further, the opening/closing valve 6 is opened/closed by a valve lifter 20 in an electromagnetic valve driving device, which will be described later, in response to commands from the controller 10.

The main combustion chamber 8 is mainly formed by the lower surface of the head of the cylinder head 3, the cylinder liner 4, and the piston head of the piston 7 that reciprocates within the cylinder liner 4, and is further formed in the piston head of the piston 7. The recess 13 also constitutes a part of the main combustion chamber 8. A piston ring made of a metal material, ceramic material, etc. is fitted into the piston ring groove of the piston 7. A multi-hole nozzle 15 with a small fuel flow rate and a glow plug 12 are arranged on the lower surface of the head constituting the main combustion chamber 8 . A plurality of nozzles of the multi-nozzle nozzle 15 for spraying alcohol fuel are opened into the main combustion chamber 8, and the heating portion of the glow plug 12 is disposed within the main combustion chamber 8. By the way, if the auxiliary chamber 5 is shut off when the engine is partially loaded, a direct combustion method is achieved in which only the main combustion chamber 8 is combusted, the compression ratio becomes large, and the main combustion chamber 8 becomes rich in surplus air. In this state, when alcohol fuel is sprayed into the main combustion chamber 8 from the plurality of nozzles of the multi-nozzle nozzle 15, the spray energy of the multi-nozzle nozzle 15 creates a good relationship between the alcohol fuel and the abundant air within the main combustion chamber 8. A mixture of mixtures can be produced. Further, the glow plug 12 is controlled on and off by commands from the controller 10, and has a function of promoting vaporization or assisting ignition of the alcohol fuel sprayed into the main combustion chamber 8.

Furthermore, a single-hole throttle nozzle 17 with a large fuel flow rate is arranged on the wall 22 constituting the subchamber 5. As shown in FIG. 2, the nozzle of the throttle nozzle 17 that sprays alcohol fuel opens, for example, in a direction along the inner wall surface of the cylindrical auxiliary chamber 5 with a spray trajectory extending from the throttle nozzle 17 into the auxiliary chamber 5. The alcohol fuel sprayed in the direction of the arrow is sprayed into a swirl. Therefore, the main combustion chamber 8
The air flowing into the sub-chamber 5 from the sub-chamber 5
A mixing zone can be created by a single hole in the internal swirl, and then secondary mixing can be performed by a reverse squish blowing out from the subchamber 5 to the main combustion chamber 8. Therefore, stratified combustion can be realized by single-order pores, and the speed of diffusive combustion can be increased.

The multi-nozzle nozzle 15 and the throttle nozzle 17 spray alcohol fuel supplied from the fuel injection pump 11 into the main combustion chamber 8 and the auxiliary chamber 5, respectively. The fuel injection pump 11 is a fuel injection pump equipped with a switching device that switches to supply alcohol fuel to either the multi-nozzle nozzle 15 or the throttle nozzle 17 according to a command from the controller 10. This fuel injection pump 11
The switching device includes, for example, an electromagnetic valve configured to be able to switch the flow path, and the electromagnetic valve switches the wave path in accordance with a command from the controller 10 to transfer the alcohol fuel from the fuel injection pump 11 to the multi-nozzle nozzle 15. Or it is configured so that it can be supplied to the throttle nozzle 17. Further, the fuel injection pump 11 is connected to the throttle nozzle 1
7 into the main combustion chamber 8 from the auxiliary chamber 5 or the multi-nozzle nozzle 15 is detected by a load sensor 16, and the detected value is input to the controller 10 as a load signal value. The controller 10 includes a load sensor 1
In accordance with the load signal value input from 6, a multiple command is issued to the fuel injection pump 11, and control is performed to switch the fuel injection pump 11 to either the multi-hole nozzle 15 or the throttle nozzle 17, and the fuel injection pump The alcohol fuel supplied from 11 is controlled to be sprayed from a multi-hole nozzle 15 or injected from a throttle nozzle 17. In addition, by providing the glow plug 12 in the main combustion chamber 8, especially when the engine load is partial or when starting the engine,
The alcohol fuel sprayed from the multi-hole nozzle 15 is accelerated in vaporization, or ignition errors are prevented to ensure smooth combustion, thereby preventing the generation of unburned gas such as aldehyde.

In this alcohol engine, the load sensor 16 that detects the load state of the engine is configured to detect the flow rate of alcohol fuel supplied from the fuel injection pump 11 to the multi-nozzle nozzle 15 or the throttle nozzle 17. Depending on the situation, it may be configured to detect the amount of depression of the accelerator pedal. The controller 10 also controls the injection timing and injection amount of the fuel injection pump 11,
It is possible to control injection timing, etc., and these conditions are controlled to optimal conditions according to the operating state of the engine. Further, an intake/exhaust port 2 is formed in the cylinder head 3, and an intake/exhaust valve 1 for opening/closing the intake/exhaust port 2 is arranged so as to be guided by a valve guide 27 to open/close. Although not shown, the cylinder head 3 is fixed to the cylinder block via a gasket. Furthermore, cylinder liners 4 are fitted into each of the plurality of cylinders formed in the cylinder block.

In the alcohol engine according to the present invention, when the engine is under low load or when the engine is started, the communication hole 14 that communicates the auxiliary chamber 5 and the main combustion chamber 8 is maintained in a closed state by the opening/closing valve 6. Therefore, the compression ratio increases. The large compression ratio allows for smooth ignition of the alcohol fuel, and since the glow plug 12 is turned on, the glow plug 12 promotes vaporization of the alcohol fuel, ensures ignition, and prevents ignition errors. and prevent the generation of unburned gas. That is, the controller 10
receives the detection signal from the load sensor 16, and in response to the detection signal having a signal value lower than a predetermined set value, that is, a partial load signal, turns on the opening/closing valve 6 to maintain the communication hole 14 in a closed state. The controller 10 performs direct injection combustion only in the combustion chamber 8, and assists in ignition or promotes vaporization by energizing the glow plug 12.The controller 10 receives a detection signal from the load sensor 16 and uses the detection signal In response to a signal value higher than a predetermined set value, that is, a high load signal, the on-off valve 6 is kept open, the communication hole 14 is opened, and the sub-chamber 5 and the main combustion chamber 8 are communicated with each other, thereby achieving sub-chamber type combustion. make the operation take place. In this case, since the combustion chamber is at a high temperature, the alcohol fuel can be vaporized well to generate an air-fuel mixture, so the glow plug 12 is controlled to be turned off.

The operation of the opening/closing valve 6 is driven by a valve lifter 20 of an electromagnetic valve driving device that performs opening/closing operation according to commands from the controller IO. By making the on-off valve 6 from the above-mentioned ceramic material, heat resistance can be improved, and by using alcohol fuel such as methanol as the fuel, carbon is added to the area between the valve face of the on-off valve 6 and the valve seat of the communication hole 14. No deposits are generated, and opening/closing operation failure of the opening/closing valve 9 due to carbon deposits does not occur.

Next, an example of an electromagnetic valve drive device that can be incorporated into this alcohol engine will be described.

The communication hole 14 is opened and closed by the valve face coming into contact with or separating from the valve seat 9 formed in the communication hole 14 as the opening/closing valve 6 moves up or down. Therefore, the amount of air taken into the auxiliary chamber 5 is controlled by the opening/closing operation or amount of opening/closing of the communication hole 14. A movable element 23 made of a magnetic material such as soft iron is fixed to the upper end of the valve stem 19, and a movable element coil 24 is provided on this movable element 23. Further, a stator 25 made of a magnetic material such as soft iron is installed above the mover 23, and the stator 25 is provided with a stator coil 26. Therefore, in order to open and close the opening/closing valve 6 in response to a command from the controller 10, the stator coil 24 and the stator coil 26 are energized by the command from the controller 10.
5 attracts the movable element 23 and drives the opening/closing valve 6 downward. In addition, by cutting off the movable coil 24 and stator coil 26 in response to a command from the controller 10, the movable coil 23 is connected to a valve spring (not shown).
It is separated from the stator 25 by the spring force of
The on-off valve 6 is driven upward, and the on-off valve 6 closes the communication hole 14 . However, although not shown, a valve spring is disposed between the valve spring seat formed on the upper surface of the cylinder rod 3 and the movable element 23. Therefore, the opening/closing valve 6 normally closes the communication hole 14, that is, is closed, by the spring force of the valve spring. In addition, the valve lifter 20 is not limited to the above-mentioned configuration, and since it sequentially changes the contact position of the valve seat,
Of course, the opening/closing valve 6 may be configured to be rotatable so that the position of the contact portion can be shifted by vertical movement.

Furthermore, regarding the on-off valve 6 that is operated by electromagnetic force, since the valve itself is made of ceramic material, iron powder etc. may be present on the valve face of the on-off valve 6 and the sliding part of the valve stem 19. There is no adsorption. However, if iron powder or the like is adsorbed to the sliding parts of the valve face and valve stem 19, the sealing condition of the opening/closing valve 6 with the valve seat 9 will deteriorate, and the frictional resistance of the sliding parts will increase, resulting in seizures and other problems. This is because an unfavorable situation will occur.

By configuring the on-off valve 6 as described above,
When the controlled current from the controller 10 is energized or cut off to the mover coil 24 and the stator coil 26, the stator 25 can separate or attract the mover 23 against the urging force of the valve spring. Therefore, the on-off valve 6 can move down or up, and the valve face of the on-off valve 6 can open or close the communication hole 14. Although the device for opening and closing the intake and exhaust valves 1 is not shown, the same applies to the intake and exhaust valves 1 as described above. Opening and closing operations can be performed using the valve lifter of the magnetic valve drive device.

The electromagnetic valve drive device that can be incorporated into this alcohol engine is provided with a load sensor 16 to detect the load on the engine.

This load sensor 16 detects the engine load, and in this embodiment, it detects the amount of fuel supplied to the engine from the fuel injection pump 11 or by detecting the amount of depression of the accelerator pedal. It is possible. Therefore, the amount of fuel supplied to the engine and/or
Alternatively, the valve can be controlled by inputting a signal of the amount of depression of the accelerator pedal to the controller 10 as an engine load signal.

Next, an example of the operation of the alcohol engine according to the present invention will be described with reference to FIGS. 1 and 3. Third
The figure is a process flow diagram showing an example of the control operation of the alcohol engine according to the present invention.

When the engine is started, the fuel injection pump 11, the electric valve drive device for the intake and exhaust valves 1, the valve train, etc. are controlled.

First, as a first step, when starting the engine, the opening/closing valve 6 is operated to close according to a command from the controller 10, the communication hole 14 is closed, and combustion is performed at a high compression ratio only in the main combustion chamber 8. At this time, according to a command from the controller 10, alcohol fuel is supplied from the fuel injection pump 11 to the multi-nozzle nozzle 15, and the alcohol fuel is sprayed from the multi-nozzle nozzle 15 into the main combustion chamber 8 with spray energy. Further, the glow plug 12 is turned on and energized to promote vaporization of the alcohol fuel injected from the multi-nozzle nozzle 15 into the main combustion chamber 8 and to assist in igniting the alcohol fuel.

Next, in order to detect the engine load Lt by the load sensor 16, the fuel injection pump 11 is connected to the multi-nozzle nozzle 1.
Detects the amount of alcohol fuel supplied to No. 5. The detected fuel supply amount signal supplied to the multi-nozzle nozzle 15 is input to the controller IO as an engine load signal (step 30).

In the controller 10, the engine load detected by the load sensor 16 is a predetermined engine load calculated in advance. Compare and judge whether it is greater than 1 (
Step 31).

:27) If the engine load Lt is larger than the predetermined engine load LE+ as a result of the comparative judgment of tff-ra10, the engine is under high load, combustion is actively occurring, and there is no air inside the combustion chamber. The temperature is high. Therefore, the controller 1 receives a high load signal from the engine and issues a command to drive the valve lifter 20 of the electromagnetic valve drive device to maintain the on-off valve 6 in the open state.By opening the on-off valve 6, the main combustion The combustion method is changed to a pre-chamber type combustion method that uses both the chamber 8 and the pre-chamber 5 (step 3).
2). In addition, the temperature inside the main combustion chamber 8 is high due to active combustion, and the vaporization of the alcohol fuel is promoted, so there is no need to assist in ignition.
Turn off the glow plug 12 (step 33),
By maintaining the opening/closing valve 6 in the open state, a low compression ratio combustion method using the main combustion chamber 8 and the auxiliary chamber 5 is established (step 34).
The fuel injection pump 11 switches the supply of alcohol fuel to the throttle nozzle 17 side (step 35).Next, the switching operation of the fuel injection pump 11 injects alcohol fuel from the throttle nozzle 17 into the auxiliary chamber 5, and the alcohol fuel is switched to the throttle nozzle 17 side. Set the injection timing to the top dead center of the compression process T, D, C
(Step 36), the air flowing from the main combustion chamber 8 into the auxiliary chamber 5 is forced in while forming a swirl around the valve stem 19 of the opening/closing valve 6. The alcohol fuel injected into the pre-chamber 5 forms a single pore mixing zone to produce a good air-fuel mixture, a part of the fuel ignites and burns, and the flame flows back from the pre-chamber 5 to the main combustion chamber 8. The squish forms a swirl and blows out, and the fuel and air are secondary mixed to create a perfectly good air-fuel mixture, and the fuel equivalence ratio is suddenly reduced, resulting in NOx-generating combustion at high temperature and high oxygen concentration. By this kind of control, the alcohol fuel can be combusted at a low compression ratio, and the inside of the main combustion chamber 8 and the sub-chamber 5 are Since the combustion of alcohol fuel is active and the temperature is high, the vaporization of alcohol fuel is promoted and a good air-fuel mixture is generated, and the injected alcohol fuel is promoted to vaporize and burns smoothly. It can prevent the generation of unburned gas and suppress the generation of NOX.Next, it determines whether or not to continue driving the engine, and in the processing process, there are abnormal signals from various sensors installed on the engine. If there is no abnormality signal and the engine continues to be driven, the process returns to step 30 and the control is repeated.Furthermore, if the engine is stopped or if there is an abnormality signal, The control process for the operation of this alcohol engine is ended (step 39).

Further, in step 31, as a result of the comparative judgment of the controller IO, if the engine load is smaller than the predetermined engine load L□, the engine is under low load;
In order to use only the main combustion chamber 8 and perform combustion with a high compression ratio, the valve lifter 20 of the electromagnetic valve drive device is driven by a command from the controller 10, and the opening/closing valve 6 is controlled by the spring force of the valve spring. Valve seat 9
By maintaining the communication hole 11 in a closed state and closing the communication hole 14 (step 40),
The auxiliary chamber 5 is closed, and only the main combustion chamber 8 is used, resulting in combustion at a high compression ratio (step 41).According to a command from the controller 10, the fuel injection pump 11 switches the alcohol fuel supply to the multiple injection holes. It is switched to the nozzle 15 side (step 42).

Furthermore, the glow plug 1 is activated by a command from the controller 10.
2 is turned on and energized to promote vaporization and ignition of the alcohol fuel (step 43).Next, the fuel injection pump 11 is operated to inject alcohol fuel from the multi-nozzle nozzle 15 into the main combustion chamber 8. The alcohol fuel is sprayed and the injection timing of the alcohol fuel is set before the top dead center T, D, C, 309 of the compression process (step 44). Through such control, the alcohol fuel is combusted at a high compression ratio. Then,
A good air-fuel mixture is generated, the injected alcohol fuel burns smoothly, and the generation of unburned gas such as aldehyde can be prevented (step 45).Next, it is determined whether or not to continue driving the engine, and In the processing process, it is determined whether or not there is an abnormal signal from various sensors provided for the engine (step 46), and if there is no abnormal signal and the engine continues to be driven, the process proceeds to step 3.
The value returns to 0 and the control process is repeated. If the engine is to be stopped or if there is an abnormality signal, the alcohol engine operation control process is terminated (step 47).

〔Effect of the invention〕

The alcohol engine according to the present invention is configured as described above and has the following effects.

That is, this alcohol engine includes an on-off valve that opens and closes a communication hole that communicates between a main combustion chamber equipped with a multi-hole nozzle and an auxiliary chamber that includes a throttle nozzle, a load sensor that detects the engine load, and a load sensor that detects the engine load. In response to a partial load signal, the on-off valve closes the communication hole to spray alcohol fuel from the multi-nozzle nozzle, and in response to a full load signal, the on-off valve opens the communication hole to spray the alcohol fuel from the multi-nozzle nozzle. Since the controller includes a controller that controls the injection of alcohol fuel from the throttle nozzle, the controller receives a partial load signal of the engine from the load sensor, issues commands to the on-off valve and the fuel injection pump, and instructs the on-off valve and the fuel injection pump. The communication hole is shut off, the auxiliary chamber is closed, the compression ratio is set high (for example, 20 to 21) so that only the main combustion chamber is used, and the fuel injection pump is switched to the multi-nozzle side. Combustion is performed by a direct injection combustion method in which alcohol fuel is sprayed into the main combustion chamber from the multi-nozzle nozzle, and since there is plenty of surplus air in the main combustion chamber, the spray energy of the multi-nozzle nozzle is This produces a good air-fuel mixture, ensures good combustion, prevents the generation of odors, pungent odors, etc., reduces the generation of hydrocarbons, improves starting performance, and improves fuel efficiency. be able to.

Also, when the engine is under full load, the opening/closing valve is maintained in an open state to open the pre-chamber to achieve a low compression ratio (for example,
Combustion is performed in steps 14-15).

That is, at full load, the main combustion chamber and the auxiliary chamber are used to perform combustion in the auxiliary chamber type combustion mode, and after creating a single hole mixing zone in the swirl in the auxiliary chamber by the throttle nozzle, the reverse combustion is performed. The squish causes secondary mixing between the air and the atomized fuel, realizing stratified combustion by single-order pores and increasing the speed of diffusive combustion.

However, under full load, combustion occurs actively, and if only the main combustion chamber is combusted, it may spontaneously ignite and cause non-king, so the auxiliary chamber is used to carry out combustion at a low compression ratio. It is. Furthermore, at full load, combustion is active and the temperature inside the main combustion chamber is high, promoting vaporization of the alcohol fuel, and in the compression process, air flows from the main combustion chamber to the auxiliary chamber through the communication hole. The air flows in as a squish, and the alcohol fuel sprayed before the top dead centers T, D, and C quickly generates a good mixture as described above and ignites, causing a part of the fuel to burn. , the diffusion combustion period is not prolonged, and then the flame is blown out from the auxiliary chamber to the main combustion chamber by reverse squish;
Secondary mixing is performed to generate a good air-fuel mixture, and the fuel equivalence ratio is rapidly lowered and the combustion temperature is lowered.
It is possible to perform combustion that suppresses the generation of
Prevents the generation of exhaust gas odors, irritating odors, etc.

Moreover, the on-off valve is manufactured from a ceramic material,
The wall that constitutes the auxiliary chamber and has a valve guide at the top and a valve seat at the bottom coaxially formed is made of ceramic material in an integral structure, and as a ceramic material, it has a small coefficient of linear expansion and is resistant to wear. Excellent materials, e.g.
By selecting a ceramic material such as silicon nitride (Si3N4), silicon carbide (SiC), or a composite ceramic material, the structure of the subchamber is simple, heat resistance is improved, and strength is ensured, and the wall is In addition to improving durability, the valve guide and the valve seat are arranged on a concentric axis to improve accuracy, and the clearance between the valve guide and the valve stem is eliminated to prevent leakage of high pressure gas, The sliding characteristics of the opening/closing valve are improved. Further, the air flowing into the subchamber by squishing from the throttle nozzle and the alcohol fuel sprayed before the top dead center T, D, and C form a single hole mixing zone around the valve stem of the opening/closing valve. Quickly generate a mixture while forming a swirl.

Therefore, in this alcohol engine, the fuel equivalence ratio (
During combustion in the pre-chamber, where the amount of fuel (fuel/air) is large, the generation of NOx is suppressed, and since alcohol fuel is used, the fuel contains oxygen, so less smoke is generated than with gasoline or diesel oil. Furthermore, no carbon deposits occur on the valve face, valve seat, etc., and valve malfunctions do not occur.

In addition, in this alcohol engine, a glow plug is arranged in the main combustion chamber, so that during partial load, the glow plug is turned on by a command from the controller, and alcohol fuel with a large latent heat of vaporization is turned on by turning on the glow plug. It is possible to promote vaporization of the alcohol fuel, improve ignitability to prevent ignition errors, improve combustion of the alcohol fuel, and prevent generation of unburned gas such as aldehyde.

Furthermore, since the opening/closing valve was opened and closed by an electromagnetic valve driving device controlled by commands from the controller,
Independently of the rotation of the crankshaft, the opening and closing valve can be freely controlled to open and close under the above conditions, that is, the opening and closing valve can be maintained in the open or closed state in immediate response to the operating state of the engine. , response can be improved and engine performance can be improved.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a sectional view showing an embodiment of the alcohol engine according to the present invention, FIG. 2 is a sectional view showing an example of the subchamber shown in FIG. 1, and FIG. FIG. 3 is a processing flow diagram showing an example of the operation of the alcohol engine of FIG. 1-----Single intake and exhaust valve, 3.--1--Cylinder head, 5-.-Subchamber, 6.--Opening/closing valve, 8.--
-Main combustion chamber, 9-...-Valve seat, 10----
・Controller, 11...Fuel injection pump, I2...
- Curved glove lug, 14... series of holes, 15-11-
-Multi-hole nozzle, 16--Load sensor, 17--
・-Throttle nozzle, 19--1...Valve stem,
20-- Valve lifter, 21- Valve guide, 22- Face wall body.

Claims (3)

[Claims] (1) An on-off valve that opens and closes a communication hole that communicates a main combustion chamber with a multi-nozzle and an auxiliary chamber with a throttle nozzle, a load sensor that detects the engine load, and a partial load signal from the load sensor. In response, the on-off valve closes the communication hole to spray alcohol fuel from the multi-nozzle nozzle, and in response to the full load signal, the on-off valve opens the communication hole to spray alcohol from the throttle nozzle. An alcohol engine consisting of a controller that controls fuel injection. (2) The opening/closing valve is made of a ceramic material, and the wall forming the sub-chamber and having a valve guide on an upper part and a valve seat on a lower part on a concentric axis is made of a ceramic material in an integral structure. Alcohol engine described in. (3) Claim 1, wherein a glow plug is arranged in the main combustion chamber.
Alcohol engine described in.