JP4060897B2 - Control method of sub chamber type gas engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control method mainly including supply air pressure control in a sub-chamber gas engine including a supercharger and supplying a lean air-fuel mixture.
[0002]
[Prior art]
A conventional sub-chamber gas engine having a supercharger and using a lean air-fuel mixture will be described with reference to FIG.
An outside air introduction pipe 1 is introduced into the blower Ta of the supercharger T, and an exhaust discharge pipe 2 is extended from the turbine Tb. Then, an air supply passage 3 is connected from the blower Ta to the combustion main chamber in the combustion chamber Ea of the engine E (a combination of the combustion main chamber and the combustion subchamber), and from the combustion main chamber to the turbine Tb. On the other hand, an exhaust passage 4 is provided. An intercooler IC is provided in the air supply passage 3, and a throttle 5 is provided downstream thereof.
[0003]
As a fuel gas supply structure, a check valve 6 faces the combustion sub chamber in the combustion chamber Ea, and the fuel gas G is supplied from the gas compressor 12 to the sub chamber regulator R2 ″ via the air-fuel ratio control valve V. The fuel gas G fed in and regulated by the sub-chamber regulator R2 ″ is fed into the combustion sub-chamber via the check valve 6.
On the other hand, as a structure for introducing a lean air-fuel mixture into the combustion main chamber in the combustion chamber Ea, a mixer M is provided in the outside air introduction pipe 1 for the main chamber. The fuel gas G regulated by the regulator R1 ″ is sent through the air-fuel ratio control valve V, mixed with the air A to form a lean air-fuel mixture, and supplied to the air supply passage 3 from the blower Ta of the supercharger T. It has become a thing.
A balancing tube 13 for extracting the supply air pressure (lean mixed air pressure) on the downstream side of the throttle 5 in the supply air passage 3 is provided as a detection means for regulating the pressure in the sub chamber regulator R2 ″.
[0004]
Further, the adjustment for keeping the air-fuel ratio of the lean air-fuel mixture as the supply air constant is performed by electronic control, that is, by the controller C, the air-fuel ratio in the fuel gas supply path to the mixer M of the outside air introduction pipe 1 The control valve V is controlled.
The engine E is provided with an angle sensor S1 (detecting an inclination angle of an accelerator lever or the like) as means for detecting the set value of the engine speed, and a top dead center sensor S2 as means for detecting the engine speed. Provided.
Further, an air supply pressure sensor S3 is provided on the downstream side of the throttle 5 in the air supply passage 3 as means for detecting the air supply pressure. These detection signals are input to the controller C. The throttle 5 is controlled by electronic control based on detection of the number of engine revolutions and the number of engine revolutions by the angle sensor S1 and the top dead center sensor S2 as the speed control means, and the supply of the lean air-fuel mixture is controlled. In addition to adjusting the air volume, the opening degree is also adjusted for air supply pressure control based on the detection of the air supply pressure sensor S3.
[0005]
[Problems to be solved by the invention]
First, conventionally, the fuel gas regulated by the sub chamber regulator R2 ″ is supplied to the combustion sub chamber via the check valve 6, but in this case, the force for opening the check valve 6 is small. Therefore, the malfunction of the check valve 6 is likely to occur.
[0006]
Conventionally, the adjustment of the air supply amount as the speed control means has been made only by adjusting the opening of the throttle 5, but the lean air-fuel mixture as the air supply to the combustion main chamber is formed on the upstream side of the throttle 5. Therefore, the degree of pressure loss through the throttle 5 is considerably increased, the efficiency is poor, and the supply pressure on the upstream side of the throttle 5 is increased accordingly, so that the burden on the supercharger T is increased. It was.
Further, this increases the internal pressure of the exhaust passage 4, so that the scavenging efficiency is deteriorated and NO in the exhaust gas is reduced. _X Was also increasing.
[0007]
As a solution to this, it is conceivable to supply fuel gas to the air supply passage on the downstream side of the throttle. In this case, the pressure upstream through the throttle is reduced because only the air upstream of the fuel gas is not mixed in the throttle upstream. In adopting this structure, it is conceivable that the fuel gas regulator is an I / P regulator and the fuel gas is regulated by electronic control based on the detected load value. In this case, the supply pressure is also detected by the load. Even if the electronic control is performed based on the above, there is a problem that an error occurs in the air-fuel ratio in the supply air because the adjustment of the fuel gas does not correspond to the actual increase or decrease in the supply air pressure. I / P regulators are also expensive.
[0008]
In addition, in the supply air pressure control, the supply air pressure increases or decreases rapidly when the load is shut off (when the load is separated from the engine output shaft) and when it is turned on (when the load is connected to the engine output shaft). . When the load is shut off, the supply air pressure increases at once. Therefore, conventionally, the throttle 5 is closed to suppress the increase in the supply air pressure. However, the closing operation of the throttle 5 takes time, and it is not in time. There was a problem that the supply air pressure increased and the engine speed increased. In addition, a temporary increase in the supply air pressure causes a surging phenomenon of the engine.
[0009]
Further, the conventional speed control by adjusting the opening of the throttle 5 is based only on the detection of the engine speed, and does not respond to knocking. Therefore, knocking is likely to occur particularly when the load is applied.
In order to cope with knocking, it is effective to temporarily increase the fuel gas concentration in the supply air that is a lean air-fuel mixture, that is, to temporarily reduce the air-fuel ratio. When the fuel gas concentration in the supply air is increased in this way, the fuel gas concentration in the combustion subchamber increases as the fuel gas concentration in the combustion main chamber increases, and the concentration becomes abnormally high and enters the combustion subchamber. There was a problem that the spark plug that was exposed caused misfire.
[0010]
[Means for Solving the Problems]
The present invention is configured as follows to solve the above-described problems.
A combustion chamber (Ea) formed in the cylinder is composed of a combustion main chamber and a combustion subchamber, and an air supply passage (3) and an exhaust passage (4) between the combustion main chamber and the supercharger (T). ), And a wastegate (7) is interposed between the exhaust passage (4) and the exhaust discharge pipe (2) of the supercharger (T), and is connected to the air supply passage (3). Is provided with a throttle (5), and fuel gas is supplied to the air supply passage (3) on the downstream side of the throttle (5) by an electronically controlled main chamber fuel gas injection device (I1), A fuel gas is formed from the sub-chamber fuel gas injection device (I2) through the check valve (6) to the ignition combustion sub-chamber that is formed in a lean mixture and is communicated with the combustion main chamber. In a sub-chamber gas engine with a structure for supplying air, the supply air pressure control method controls the supply air pressure setting graph (α) with respect to the load size. Is stored in Ra (C), against the detected value of the output sensor (S4) reads the target supply air pressure, performed by comparing the actual supply air pressure value by the boost pressure sensor (S3), The supply air pressure control means is When the load is low, the opening degree of the throttle (5) is adjusted when the wastegate (7) is fully opened. When the load is high, the opening degree of the wastegate (7) is adjusted when the throttle (5) is fully open. Configured to do In the fuel gas pressure control method, the load is read by the output sensor (S4), collated with the stored fuel gas pressure setting graph (γ) assuming the supply pressure setting graph (α), and used for the main chamber.・ Adjustment control is performed by regulators (R1, R2) for main chambers and sub chambers that control the pressure of the fuel gas injectors (I1, I2) for sub chambers. The target engine speed is read, the actual engine speed is read by the top dead center sensor (S2), the injection period of the main chamber fuel gas injection device (I1) is calculated and changed to the target engine speed. To match.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing a basic control system for a sub-chamber type gas engine according to the present invention, and FIG. 2 is a setting of supply air pressure corresponding to the magnitude of a load in the basic control system for the sub-chamber type gas engine shown in FIG. FIG. 5 is a diagram illustrating the operation of the throttle and the wastegate, in which (a) is a diagram illustrating an air supply pressure setting corresponding to the magnitude of the load, (b) is a diagram illustrating a throttle opening corresponding to the magnitude of the load; c) is a diagram showing the opening degree of the wastegate corresponding to the magnitude of the load, FIG. 3 is a flowchart of the supply pressure control by the operation of the throttle and the wastegate in the basic control system, and FIG. 4 is the load chart in the basic control system. FIG. 5 is a flow chart of fuel gas supply pressure control in the basic control system, FIG. 6 is a diagram showing the correlation between the fuel gas supply pressure and the supply air pressure to the main chamber / sub chamber fuel gas injectors with respect to the size; FIG. 7 is a flow chart of the speed control in the basic control system, and FIG. 7 shows a control system in the case where the fuel gas main chamber and sub chamber regulators are based on the supply air pressure extraction in the sub chamber type gas engine according to the present invention. FIG. 8 is a diagram showing a control system when a bypass passage is provided between the main chamber and sub chamber fuel gas passages in order to cope with a load interruption, and FIG. 9 shows the control system shown in FIG. FIG. 10 is a diagram showing a control system in the case where a non-king sensor is provided to cope with load application in the sub-chamber type gas engine according to the present invention. FIG. 11 is a time schedule diagram showing various control operation procedures when a load is applied using the control system shown in FIG.
[0012]
First, a basic control system for a sub-chamber gas engine according to the present invention will be described with reference to FIG.
The same reference numerals as those in FIG. 12 illustrating the above-described prior art indicate the same members.
In the present invention, the speed control, the supply air pressure, and the fuel gas pressure are controlled by electronic control, and a controller C is provided. An angle sensor S1 for detecting the engine speed and a top dead center sensor S2 for detecting the actual engine speed are provided, and an air supply pressure sensor S3 is provided in the air supply passage 3 on the downstream side of the throttle 5. ing.
Further, in FIG. 1, the engine E is provided with an output sensor S4 as load detecting means, and a cam timing sensor S5 related to the supply / exhaust timing.
[0013]
In the sub-chamber type gas engine of the present invention shown in FIG. 1, what is different from the conventional one is a fuel gas supply structure.
That is, the fuel gas G common to the main chamber and the sub chamber is supplied through the gas filter 8 at a constant supply pressure, and is branched to the main chamber regulator R1 and the sub chamber regulator R2. Send it in. Both regulators R1 and R2 are I / P regulators, and the gas pressure can be freely set by electronic control, and the fuel gas pressure is regulated by each regulator R1 and R2 according to the magnitude of the load. Is.
The fuel gas G regulated by the main chamber regulator R1 is injected into the supply passage 3 on the downstream side of the throttle 5 by the main chamber fuel gas injection device (injector) I1, while the fuel gas G for the sub chamber is used. The fuel gas G regulated by the regulator R2 is injected toward the check valve 6 by the sub chamber fuel gas injection device (injector) I2, and is supplied to the combustion sub chamber in the combustion chamber Ea via the check valve 6. Is done.
[0014]
In this way, the fuel gas G is injected by the injection device. In particular, the high pressure gas is injected from the sub chamber fuel gas injection device I2 to the check valve 6 for the combustion sub chamber. 6 is increased, and the occurrence of malfunctions as in the prior art is reduced.
[0015]
The outside air introduction pipe 1 is not provided with a conventional mixer M for mixing air and fuel gas, and only the air A is supercharged up to the upstream side of the throttle 5 in the air supply passage 3. The fuel gas G is directly injected from the main chamber fuel gas injection device I1 on the downstream side of the throttle 5 and mixed with the air introduced through the throttle 6 to form a lean mixture. The supply air is supplied to the combustion main chamber of the combustion chamber Ea.
Therefore, since only the air A passes through the throttle 5 first, the pressure loss becomes low, and the supercharger T also supercharges only the air A, so that the boost pressure can be afforded.
[0016]
Furthermore, an openable / closable waist gate 7 is provided between the exhaust passage 4 and the exhaust discharge pipe 2 extending from the turbine Tb of the supercharger T. When the internal pressure of the exhaust passage 4 increases, Since the gate 7 is opened and the exhaust gas is allowed to flow directly into the exhaust discharge pipe 2 so that the exhaust pressure can be reduced, the burden on the supercharger T can be reduced, and it contributes to the promotion of scavenging in the combustion chamber Ea. NO in exhaust _X It also leads to reduction.
[0017]
In particular, when the load is low, the wastegate 7 is fully opened to lower the boost pressure so that the supply air pressure does not become excessive. The opening is adjusted according to the size. On the contrary, at high load, the throttle 5 is fully opened and the supply air pressure introduced into the combustion main chamber of the combustion chamber Ea is increased so as to increase the supply air pressure so that the supply air pressure does not become insufficient. On the other hand, the waste gate 7 is actuated in the closing direction so as to increase the internal pressure of the exhaust passage 4, and the opening degree is adjusted according to the magnitude of the load. The opening / closing timings and opening settings of the throttle 5 and the wastegate 7 corresponding to the magnitudes of these loads are as shown in FIGS.
[0018]
As shown in FIG. 2 (a), it is desired to set the supply air pressure with respect to the load as shown in the graph α. Conventionally, the supply air pressure control is performed only by opening and closing the throttle 5. In the case of load 0, even if the supply air pressure is desired to be close to 0, the internal pressure of the exhaust passage 4 increases due to the exhaust boost pressure to the supercharger T (turbine Tb). The pressure could not be reduced below atmospheric pressure.
However, if the boost pressure is lowered by providing the wastegate 7 and opening it, the supply air pressure that matches the supply air pressure setting graph α can be obtained.
[0019]
As can be seen from FIGS. 2 (a) and 2 (b), the throttle 5 is fully opened when the supply air pressure coincides with the atmospheric pressure. If the supply air pressure exceeds the atmospheric pressure, the throttle 5 While the air supply pressure is controlled by the closing operation of the wastegate 7 while being fully opened, conversely, if the air supply pressure is less than the atmospheric pressure, the wastegate 7 is fully opened and the air supply is performed by the closing operation of the throttle 5. Pressure control is performed.
[0020]
The flow of air supply pressure control corresponding to the magnitude of the load will be described with reference to FIG.
First, the engine output is read by the output sensor S4, and the load is detected. On the other hand, the actual supply pressure in the supply passage 3 on the downstream side of the throttle 5 is detected by the supply pressure sensor S3. The supply pressure setting map according to the load size is stored in the controller C as shown in the supply pressure setting graph α in FIG. 2A, and the detected value of the output sensor S4 is collated with this map. Then, the target air supply pressure is read, and this is compared with the actual air supply pressure value by the air supply pressure sensor S3 to perform pressure regulation control. This pressure adjusting means is by adjusting the opening of the throttle 5 if the supply air pressure is less than the atmospheric pressure (the wastegate 7 is fully open), and if the supply air pressure is equal to or higher than the atmospheric pressure, the wastegate 7 (The throttle 5 is fully opened). Thus, when the actual supply pressure detected by the supply pressure sensor S3 matches the target supply pressure, the operation of the throttle 5 or the wastegate 7 is stopped.
[0021]
As described above, the operation of the throttle 5 and the wastegate 7 adjusts the supply air pressure in accordance with the load. However, if the fuel gas pressure is not adjusted in accordance with the increase or decrease in the supply air pressure, the air-fuel ratio is adjusted. Will be different. Since the air-fuel ratio must be kept constant regardless of the pressure increase / decrease except during the speed control, the fuel gas pressure is also adjusted in accordance with the magnitude of the load. That is, as shown in FIG. 4, the supply pressure to the regulators R1 and R2 is constant, but the fuel gas supply to the fuel gas injectors I1 and I2 via the main chamber regulator R1 and the subchamber regulator R2 The pressure is set according to the magnitude of the load as shown in the graph γ. The supply air pressure is a pressure of a lean air-fuel mixture formed by being injected from the main chamber fuel gas injection device I1 and mixed with air in the air supply passage 3 downstream of the throttle 5, as shown in the graph γ. By setting the fuel gas pressure, the supply pressure setting graph α shown in FIG. 4 shown in FIG. 2A is obtained.
[0022]
The control procedure of the fuel gas pressure in each of the regulators R1 and R2 is as shown in FIG. That is, the load is read by the output sensor S4, and this is collated with the fuel gas pressure setting graph γ in the map shown in FIG. 4 to perform pressure regulation control in the main chamber and sub chamber regulators R1 and R2. is there.
[0023]
The fuel gas pressure setting graph γ is set on the assumption that the supply air pressure is as shown in the supply air pressure setting graph α. However, when the supply air pressure control means is only the throttle 5 as in the prior art, the supply air pressure setting is as shown in the graph β, an error occurs from the set value of the fuel gas pressure, and the air-fuel ratio does not become constant. By combining the control means of the throttle 5 and the waste gate 7 and the fuel gas pressure adjustment assuming that, the supply air pressure corresponding to the magnitude of the load is obtained appropriately as in the supply air pressure setting graph α for the first time. Can do it.
[0024]
Further, in the control system for the sub-chamber type gas engine shown in FIG. 1, as a point different from the conventional control system shown in FIG. 12, conventionally, the speed control means relies on the opening / closing control of the throttle 5. The main chamber fuel gas injection device I1 is controlled by the injection period.
In other words, since the opening / closing operation of the throttle 5 is not required, the supply / exhaust pressure does not increase / decrease, and the fuel gas amount is directly metered. Becomes better.
[0025]
The flow of this speed control will be described with reference to FIG. The target engine speed is read by the angle sensor S1, while the actual engine speed is read by the top dead center sensor S2. This is input to the controller C to calculate the injection period of the main chamber fuel gas injector I1, and when the actual engine speed is different from the target engine speed, the injection of the main chamber fuel gas injector I1 The period is changed to match the target engine speed.
[0026]
The following embodiments shown in FIGS. 7 to 11 are application control systems based on the basic control system shown in FIGS.
First, the control system shown in FIG. 7 is an application example on the fuel gas pressure control system.
That is, in the control system shown in FIG. 1, the main room regulator R1 and the sub-room regulator R2 are I / P regulators, that is, electronically controlled. In the control system shown in FIG. A non-electronic regulator based on the extraction of
That is, the balancing line 9 for extracting the supply pressure in the supply passage 3 on the downstream side of the throttle 5 is extended with respect to the main chamber regulator R1 ′ and the sub chamber regulator R2 ′ that are not electronically controlled, and each regulator In R1 ′ and R2 ′, the fuel gas pressure is controlled based on the actual supply air pressure obtained from the balancing line 9.
[0027]
In the control system shown in FIGS. 1 to 5, the supply air pressure is controlled by the operation of the throttle 5 and the waste gate 7, and the fuel gas pressure is controlled by the main chamber and sub chamber regulators R1 and R2, which are I / P regulators. Although the control is common to load detection, each control itself is not related. Therefore, in reality, there is a possibility that an error occurs between the supply air pressure and the fuel gas pressure and the air-fuel ratio increases or decreases. However, the main chamber and sub chamber regulators R1 ′ and R2 ′ shown in FIG. 7 regulate the fuel gas based on the actual value of the supply air pressure itself, so that an error in the air-fuel ratio does not occur. In addition, there is an advantage of low cost.
[0028]
Next, referring to FIGS. 8 and 9, the supply air pressure reduction control at the time of load interruption will be described.
First, as shown in FIG. 8, in the configuration, the main room / sub-room regulators R1 and R2 use I / P regulators. As shown in FIGS. 1, 4, and 5, load detection is performed. A control system that regulates fuel gas by electronic control is used.
Further, a fuel gas passage between the main chamber regulator R1 and the main chamber fuel injection device I1 and a fuel gas passage between the sub chamber regulator R2 and the sub chamber fuel injection device I2 are connected by a bypass passage 10. The bypass passage 10 is provided with a gas bypass valve 11, which is an on-off valve that enables only fuel gas flow from the main chamber fuel gas passage to the sub chamber fuel gas passage.
[0029]
Based on such a configuration, the supply pressure control at the time of load interruption will be described with reference to FIG.
When a load device (generator, etc.) is connected to the output shaft of the engine E via a clutch, the state in which the clutch is separated is referred to as load interruption. However, when the load is interrupted, the load suddenly becomes low. . If the load is cut off from the high load state, the throttle gate 5 is fully opened and the waste gate 7 is rapidly opened from the state in which the throttle gate 5 is closed with the control system shown in FIGS. Then, the operation of closing the throttle 5 is started. However, these operations take time, and the rapid increase of the supply air pressure cannot be suppressed, the engine speed increases rapidly, and the engine may be damaged. This increase in engine speed must be suppressed as much as possible.
[0030]
Therefore, the injection from the main chamber fuel gas injection device I1 is stopped as a means for instantaneously reducing the supply air pressure at the moment of load interruption. At the same time, the gas bypass valve 11 is opened to allow the fuel gas supplied from the main chamber regulator R1 to flow out to the sub chamber fuel gas injector I2 via the bypass passage 10. At the same time when the load is interrupted (that is, simultaneously with the decrease in the fuel gas injection into the supply passage 3), the wastegate 7 is opened to reduce the internal pressure of the exhaust passage 4.
[0031]
Here, the timing for starting the closing operation of the throttle 5 is started. If this is started together with the load interruption, the supply air existing at the downstream side of the throttle 5 no longer flows, and the supply air pressure is temporarily Increased to cause engine surging. If the closing operation of the throttle 5 is delayed a little, the internal pressure of the exhaust passage 4 is lowered by opening the wastegate 7, so that the air in the combustion chamber Ea flows toward the exhaust passage 4 and the supply air pressure is reduced. Promote the decline. In this way, the throttle 5 can be temporarily delayed and start the closing operation in consideration of the flow period of the air-fuel mixture to the exhaust side, thereby avoiding a temporary increase in the supply air pressure and reducing engine surging. .
[0032]
In addition, after the supply air pressure is reduced, the fuel gas must be injected again from the main chamber fuel gas injection device I1 in order to maintain the air-fuel ratio. Accordingly, although the injection is started again from the vicinity where the throttle 5 is closed, it takes time for the low pressure control of the fuel gas by the main chamber regulator R1 which controls the pressure based on the load detection. It is necessary to reduce the supply pressure of the fuel gas to the chamber fuel gas injection device I1. Therefore, even when the main chamber fuel gas injection device I1 starts injection, the gas bypass valve 11 is opened for a while and the main chamber fuel gas supplied from the main chamber regulator R1 through the bypass passage 10 is opened. A part of the gas flows out into the sub chamber fuel gas passage.
When the fuel gas pressure regulated by the main chamber regulator R1 becomes sufficiently low, the gas bypass valve 11 is closed, and all the fuel gas supplied from the main chamber regulator R1 is removed from the main chamber. Is supplied to the fuel gas injection device I1.
[0033]
With such a control system, particularly when the load is interrupted from a high load state, the supply air pressure can be instantaneously reduced to suppress an increase in the engine speed, and surging can be avoided at that time. .
[0034]
Finally, referring to FIG. 10 and FIG. 11, the supply air pressure control at the time of loading and the knocking control will be described. As shown in FIG. 10, the engine E is additionally provided with a knocking sensor S6 in the basic control system shown in FIG.
[0035]
As shown in FIG. 11, when a load is applied, the load is suddenly increased. At this time, in order to suppress a decrease in the engine speed, it is necessary to control to increase the air supply pressure so that the supply air pressure does not become insufficient. Therefore, the throttle 5 is fully opened and the wastegate 7 is fully closed to increase the supply air pressure.
This is possible by the basic control of the supply air pressure by the load detection shown in FIGS. Accordingly, the main chamber and sub chamber regulators R1 and R2 are also controlled by the basic control of the fuel gas pressure by the load detection shown in FIGS. The fuel gas supply pressure to the sub chamber fuel gas injection device I2 is increased.
[0036]
Furthermore, knocking occurs when this load is applied. This knocking is detected by the knocking sensor S6, and based on this, the injection period of the main chamber fuel gas injection device I1 is extended, and the air-fuel ratio of the supply air is reduced, that is, the fuel gas concentration is increased. On the other hand, in order to prevent the misfire of the ignition plug in the combustion subchamber, the injection period of the subchamber fuel gas injection device I2 is shortened so that the fuel gas concentration in the combustion subchamber does not become excessive. Thereafter, as the supply air pressure rises, the opening degree of the wastegate 7 is adjusted, and when the supply air pressure reaches a value commensurate with the magnitude of the load, there is no fear of knocking. The injection periods of I1 and the sub chamber fuel gas injection device I2 are also restored to the initial set values. Thereafter, as shown in FIG. 6, the fuel gas injection device I1 for the main chamber has its injection period adjusted for speed control.
[0037]
【The invention's effect】
The present invention uses the above-described apparatus for the control device for the sub-chamber type gas engine, and has the following effects.
A combustion chamber (Ea) formed in the cylinder is composed of a combustion main chamber and a combustion subchamber, and an air supply passage (3) and an exhaust passage (4) between the combustion main chamber and the supercharger (T). ), And a wastegate (7) is interposed between the exhaust passage (4) and the exhaust discharge pipe (2) of the supercharger (T), and is connected to the air supply passage (3). Is provided with a throttle (5), and fuel gas is supplied to the air supply passage (3) on the downstream side of the throttle (5) by an electronically controlled main chamber fuel gas injection device (I1), A fuel gas is formed from the sub-chamber fuel gas injection device (I2) through the check valve (6) to the ignition combustion sub-chamber that is formed in a lean mixture and is communicated with the combustion main chamber. In a sub-chamber gas engine with a structure for supplying air, the supply air pressure control method controls the supply air pressure setting graph (α) against the load size Is stored in Ra (C), against the detected value of the output sensor (S4) reads the target supply air pressure, performed by comparing the actual supply air pressure value by the boost pressure sensor (S3), The supply air pressure control means is When the load is low, the opening degree of the throttle (5) is adjusted when the wastegate (7) is fully opened. When the load is high, the opening degree of the wastegate (7) is adjusted when the throttle (5) is fully open. Configured to do In the fuel gas pressure control method, the load is read by the output sensor (S4), collated with the stored fuel gas pressure setting graph (γ) assuming the supply pressure setting graph (α), and used for the main chamber.・ Adjustment control is performed by regulators (R1, R2) for main chambers and sub chambers that control the pressure of the fuel gas injectors (I1, I2) for sub chambers. The target engine speed is read, the actual engine speed is read by the top dead center sensor (S2), the injection period of the main chamber fuel gas injection device (I1) is calculated and changed to the target engine speed. First, since the lean mixture as the supply air is formed by supplying fuel to the throttle downstream side in the supply passage, the supercharger supercharges only air, and To provide a wastegate Therefore, the boost pressure on the exhaust side can be reduced, and the burden on the supercharger is reduced.
And since only air passes, the pressure loss in a throttle is also reduced.
Moreover, the reduction of the exhaust side pressure by the wastegate is caused by NO in the exhaust. _X There is also a reduction effect.
Since the fuel gas is injected by the fuel gas injection device, the operating pressure of the check valve increases, particularly in the combustion sub chamber, and the malfunction of the check valve can be eliminated.
[0038]
In addition, by using the control method of the present invention, the control of the supply air pressure becomes more responsive than the conventional case where only the throttle is used. By fully opening it, it is possible to sufficiently reduce the supply air pressure that could not be reduced below a certain value in the past, to reduce the output loss, and to improve the suppression reaction for increasing the engine speed. On the other hand, when the load is high, the supply air pressure can be controlled by adjusting the opening degree of the wastegate, and the throttle can be fully opened, so that the engine efficiency is good.
[0039]
Further, the speed control of the present invention is not based on the throttle operation as in the prior art, but is based on the control of the injection timing of the fuel gas injection device for the main chamber, so that the control is not delayed and the reactivity is good like the throttle operation. is there. Therefore, the stability of the engine speed is improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing a basic control system for a sub-chamber gas engine according to the present invention.
FIG. 2 is a diagram showing an air supply pressure setting corresponding to the magnitude of the load and the operation of the throttle and the wastegate in the basic control system of the sub-chamber type gas engine shown in FIG. 1, wherein (a) shows the magnitude of the load. The figure which shows the supply air pressure setting corresponding to this, (b) is a figure which shows the throttle opening corresponding to the magnitude | size of a load, (c) is a figure which shows the waste gate opening degree corresponding to the magnitude | size of a load. .
FIG. 3 is a flowchart of supply air pressure control by the operation of a throttle and a waste gate in the same basic control system.
FIG. 4 is a diagram showing the correlation between the fuel gas supply pressure and the supply air pressure to the main chamber / sub chamber fuel gas injection devices with respect to the magnitude of the load in the basic control system.
FIG. 5 is a flowchart of fuel gas supply pressure control in the same basic control system.
FIG. 6 is a flowchart of speed control in the same basic control system.
FIG. 7 is a diagram showing a control system in a case where a main gas / sub chamber regulator for fuel gas is based on supply air pressure extraction in a sub chamber type gas engine according to the present invention.
FIG. 8 is a diagram showing a control system in a case where a bypass passage is provided between main chamber and sub chamber fuel gas passages in order to cope with a load interruption in the same manner.
FIG. 9 is a time schedule diagram showing various control operation procedures at the time of load interruption using the control system shown in FIG. 8;
FIG. 10 is a diagram showing a control system in a case where a non-king sensor is provided in order to cope with load application in the sub-chamber gas engine according to the present invention.
FIG. 11 is a time schedule diagram showing various control operation procedures when a load is applied using the control system shown in FIG. 10;
FIG. 12 is a diagram showing a control system for a conventional sub-chamber gas engine.
[Explanation of symbols]
E engine
Ea Combustion chamber (combustion main chamber and combustion subchamber)
R1 Main room regulator
R2 Regulator for sub chamber
I1 Fuel gas injector for main room (injector)
I2 Sub-chamber fuel gas injector (injector)
T turbocharger
Ta blower
Tb turbine
IC intercooler
C controller
S1 Angle sensor
S2 Top dead center sensor
S3 Supply air pressure sensor
S4 output sensor
S5 Cam timing sensor
S6 knocking sensor
1 Outside air introduction pipe
2 Exhaust discharge pipe
3 Air supply passage
4 Exhaust passage
5 Throttle
6 Check valve
7 Westgate
8 Gas filter
9 Balancing line
10 Bypass passage
11 Gas bypass valve

Claims (1)

A combustion chamber (Ea) formed in the cylinder is composed of a combustion main chamber and a combustion subchamber, and an air supply passage (3) and an exhaust passage (4) between the combustion main chamber and the supercharger (T). ), And a wastegate (7) is interposed between the exhaust passage (4) and the exhaust discharge pipe (2) of the supercharger (T), and is connected to the air supply passage (3). Is provided with a throttle (5), and fuel gas is supplied to the air supply passage (3) on the downstream side of the throttle (5) by an electronically controlled main chamber fuel gas injection device (I1), A fuel gas is formed from the sub-chamber fuel gas injection device (I2) through the check valve (6) to the ignition combustion sub-chamber that is formed in a lean mixture and is communicated with the combustion main chamber. In the sub-chamber type gas engine structured to supply
In the supply air pressure control method, the supply air pressure setting graph (α) with respect to the magnitude of the load is stored in the controller (C), and the target supply air pressure is read by comparing with the detected value of the output sensor (S4). Compare with the actual supply air pressure value by the pressure sensor (S3),
The supply air pressure control means adjusts the opening of the throttle (5) when the wastegate (7) is fully open when the load is low, and adjusts the wastegate ( 7) to adjust the opening ,
In the fuel gas pressure control method, the load is read by the output sensor (S4), collated with the stored fuel gas pressure setting graph (γ) assuming the supply pressure setting graph (α), and used for the main chamber.・ Controlling the pressure by the regulator for the main chamber and the regulator for the sub chamber (R1, R2) that controls the pressure of the fuel gas injection device (I1, I2) for the sub chamber,
In the speed control method, the target engine speed is read by the angle sensor (S1), the actual engine speed is read by the top dead center sensor (S2), and the injection period of the fuel gas injector (I1) for the main chamber is read. The sub-chamber type gas engine control method is characterized by calculating and changing to match the target engine speed.

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