JP2004257257A - Gas engine with controlling mechanism of fuel injection quantity during startup - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas engine capable of changing an air excess ratio in a combustion chamber with fine responsiveness, and stabilizing combustion during start up speedily. <P>SOLUTION: There is provided a fuel supply means supplying fuel to the vicinity of the combustion chamber of an air supply passage supplying air to the chamber. There is further provided a PID control means adjusting the quantity of the fuel supply by the supply means to prevent an engine stall generated due to the departure of the excess rate from a combustible range and an overshoot exceeding the rated number of rotations. When the number of rotations of the engine reaches the prescribed first rotation number before the departure from the range due to the exceeding air rate, it is speedily brought closely to the rated number by adjusting the quantity of the fuel supply by the PID control means. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a gas engine provided with a control mechanism for a fuel injection amount at the time of starting in which combustion is unstable.
[0002]
[Prior art]
FIG. 7 is a schematic system diagram showing a flow path of air and fuel gas of a conventional gas engine 200. In the gas engine 200, air and a fuel gas (main chamber fuel gas) to be supplied to the main chamber are mixed by a mixer to form an air-fuel mixture having a predetermined excess air ratio, and the air-fuel mixture is a supercharger (T / After being compressed by C) and cooled by an intercooler (I / C), the supply amount is adjusted by a throttle and supplied to a cylinder (combustion chamber / main chamber). The configuration of the mixer is described in Patent Document 1, for example.
[0003]
[Patent Document 1]
JP-A-5-19547
[0004]
Further, the fuel gas can be directly supplied to the sub-chamber, and the fuel gas supplied to the sub-chamber is supplied between the intercooler and the throttle via the starting auxiliary pipe when the gas engine 200 starts. When the engine speed reaches about 40 to 60% of the rated speed and the combustion becomes stable, the supply of fuel to the main chamber via the auxiliary starting pipe is cut off, and fuel (sub-chamber fuel gas) is supplied to the sub-chamber instead. It is supposed to.
[0005]
By the way, in the overlap period in which the intake valve and the exhaust valve are simultaneously opened, the air-fuel mixture is discharged from the exhaust passage without performing work. On the other hand, in order to increase the output, it is necessary to set a long overlap period so as not to deteriorate the knocking limit from the viewpoint of scavenging efficiency. However, in this gas engine 200, a mixer provided on the upstream side of a supercharger (compressor) generates an air-fuel mixture for combustion and supplies the air-fuel mixture to a combustion chamber (main chamber). It is difficult to increase output and improve fuel efficiency. Further, since the excess air ratio in the combustion chamber cannot be changed quickly, it takes time until the engine speed reaches the rated speed.
[0006]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a gas engine that can change the excess air ratio in the combustion chamber with good response and can stably stabilize combustion at the time of starting.
[0007]
[Means for Solving the Problems]
In order to solve the above problem, according to the first aspect of the present invention, fuel supply means for supplying fuel is provided near the combustion chamber of an air supply passage for supplying air to the combustion chamber, and the excess air ratio in the combustion chamber deviates from the flammable range. PID control means for adjusting the amount of fuel supplied by the fuel supply means so as to avoid an engine stall caused by the operation of the engine and an overshoot exceeding the rated speed. When the engine speed reaches a predetermined first engine speed before deviating from the flammable range, the PID control means adjusts the fuel supply amount so that the engine speed quickly approaches the rated engine speed. I made it.
According to a second aspect of the present invention, in the first aspect, the fuel supply amount per cycle by the fuel supply means from the start of cranking until the engine speed reaches a range of 50 to 100% of the rated speed is determined. The fuel supply amount was kept constant, and the fuel supply amount was set to 1 to 4 times the fuel supply amount required for operation at the no-load rated rotation speed.
According to a third aspect of the present invention, in the first aspect of the present invention, a lubricating oil temperature detecting means for detecting a temperature of the lubricating oil for cooling each part of the gas engine is provided, and the lubricating oil temperature detected by the lubricating oil temperature detecting means increases as the lubricating oil temperature increases. The fuel supply means was set so as to reduce the amount of fuel supply per cycle.
According to a fourth aspect of the present invention, in a gas engine having a main chamber and a sub chamber, a first fuel supply means for supplying fuel near an air supply passage for supplying air to the main chamber is provided. A second fuel supply means for directly supplying fuel to the sub-chamber without intervening is provided so that an engine stall caused by an excess air ratio in the main chamber deviating from a flammable range and an overshoot exceeding a rated speed can be avoided. PID control execution means for adjusting the amount of fuel supplied by the first fuel supply means, wherein the predetermined first engine before the engine speed deviates from the flammable range due to the excessive air ratio in the sub-chamber being too rich After reaching the engine speed, the supply of fuel to the sub-chamber is started by the second fuel supply means so that the engine speed quickly reaches the rated engine speed.
According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the engine speed at which fuel supply to the sub-chamber is started by the second fuel supply means is set within a range of 100 to 120% of the first engine speed. The adjustment of the fuel injection amount by the first fuel supply means is performed in advance between the first engine speed and the second engine speed set within the range of 120% of the first engine speed to the rated engine speed. Is performed by the set MAP control so that the engine speed approaches the rated speed promptly.
According to a sixth aspect of the present invention, in the first or fourth aspect, after the engine speed reaches a second engine speed set within a range of 120% of the first engine speed to a rated speed. And a storage means for storing a target engine speed when the fuel supply amount by the fuel supply means or the first fuel supply means is PID controlled.
According to a seventh aspect of the present invention, in the first or fourth aspect of the present invention, the opening of the regulating valve for regulating the amount of air supplied to the combustion chamber or the main chamber at the time of starting the cell is set within a range of 30 to 50%. The opening of the regulating valve was set to increase as the engine speed increased, and was set to be fully opened after the engine speed reached the first engine speed.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a system schematic diagram of a gas engine 100 for carrying out the inventions of claims 1 to 7. The gas engine 100 is of a sub-chamber type, and includes a main chamber 2 and a sub-chamber 5 as combustion chambers. In the middle of the air supply passage 3 for supplying air to the main chamber 2, the compressor section 6 a of the turbocharger 6, the throttle valve 7, the intercooler 9, and the injector 10 (fuel supply means or first fuel supply means) in this order from the upstream side. The intake port 11 having an intake valve 26 is formed at the end of the air supply passage 3 communicating with the main chamber 2.
[0009]
An exhaust port provided with an exhaust valve 27 is provided in the exhaust passage 4 for discharging exhaust gas from the main chamber 2 in the middle of the exhaust passage 4, and at a connection portion of the exhaust passage 4 with the main chamber 2. 28 are formed. The compressor section 6a provided in the air supply passage 3 is driven by the turbine section 6b.
[0010]
The flow rate of the compressed air compressed by the compressor section 6 a is adjusted by a throttle valve 7 whose opening is adjusted by an actuator 8, and is cooled by an intercooler 9. The actuator 8 is controlled by a controller 22 (CPU) connected via a signal line 30.
[0011]
The intake port 11 is provided with an injector 10, and the injector 10 is connected to one end of a main chamber fuel gas supply passage 12 provided with a regulator 13 on the way.
[0012]
As shown in FIG. 1, in the middle of the fuel gas supply passage 25, a fuel shutoff solenoid valve 37 and a gas compressor 14 are provided in this order from the upstream side. The fuel cutoff electromagnetic valve 37 is connected to the controller 22 (CPU) via a signal line 36 and is controlled to open and close by the controller 22. The fuel gas supply passage 25 branches into the main chamber fuel gas supply passage 12 and the sub-chamber fuel gas supply passage 15 downstream of the gas compressor 14. The fuel gas pumped by the gas compressor 14 can be injected from the injector 10 into the intake port 11 through the main chamber fuel gas supply passage 12. The amount of fuel gas injected by the injector 10 is adjusted by adjusting the pressure by the regulator 13 and changing the opening period (fuel injection period) of the injector 10 per cycle.
[0013]
The compressed fuel gas supplied from the gas compressor 14 is injected from the injector 10 into the intake port 11 through the fuel gas supply passage 12 for the main chamber, and the solenoid valve 16 and the regulator 17 Can also be supplied to the sub-chamber 5 via the sub-chamber fuel gas supply passage 15 having
[0014]
A check valve 18 that opens and closes according to pressure balance is provided in the fuel gas supply passage 15 for the sub chamber. When the check valve 18 opens and closes, fuel gas (sub-chamber fuel gas) is supplied into the sub-chamber 5.
[0015]
FIG. 6 is a schematic system diagram showing a flow path of air and fuel gas of the gas engine 100 according to the first to seventh aspects of the present invention. As schematically shown in FIG. 6, the gas engine 100 includes a plurality of cylinders (six cylinders in FIG. 6), and an injector 10 is provided in an intake passage near the main chamber 2 of each cylinder. The fuel gas (sub-chamber fuel gas) can also be directly supplied to the sub-chamber 5 of each cylinder provided therein.
[0016]
As shown in FIG. 1, the engine main body 1 is provided with an engine speed detector 21 which detects a projection of a gear (not shown) provided on a flywheel 20 to detect the engine speed. The engine speed detector 21, the injector 10, and the solenoid valve 16 are connected to the controller 22 via signal lines 31 to 33, respectively. Signals are transmitted and received between these devices and the controller 22 via the signal lines 31 to 33. The controller 22 controls the fuel injection period (the opening period of the solenoid valve) and the injection start timing (the timing at which the solenoid valve starts to be opened) by the injector 10.
[0017]
The lubricating oil that has cooled each heat generating portion of the engine body 1 is cooled by the lubricating oil cooler 23. The temperature of the lubricating oil discharged from the engine body 1 is detected by a temperature detector 24 provided at the inlet 23a of the lubricating oil cooler 23. The temperature data detected by the temperature detector 24 is transmitted to the controller 22 via a signal line 34.
[0018]
An ignition plug 19 is provided in the sub-chamber 5. The spark plug 19 and the controller 22 are connected by a signal line 35, and a signal is transmitted from the controller 22 to the spark plug 19 to control the spark ignition timing.
[0019]
When the gas engine 100 is started, the excess air ratio in the main chamber 2 is infinitely large, and the engine speed is 200 min until the excess air ratio at which explosion and combustion are possible is achieved. ^-1 It is started (driven) by a cell motor (not shown) until it reaches the degree.
[0020]
In the gas engine 100 shown in FIG. 1, since the injector 10 for injecting the fuel gas into the intake port 11 is provided, the excess air ratio in the main chamber 2 can be made rich (rich) with good responsiveness. That is, in the gas engine 100, only the air, not the air-fuel mixture containing the fuel gas, is compressed by the compressor unit 6a, the compressed air is cooled by the intercooler 9, and the cooling air and the fuel gas are mixed in the intake port 11. Therefore, since the place where the air-fuel mixture is generated is very close to the main chamber 2, the excess air ratio in the main chamber 2 can be changed with good responsiveness.
[0021]
In the overlap period in which the intake valve 26 and the exhaust valve 27 are simultaneously opened, the air-fuel mixture is discharged without performing work. In the gas engine 100, the fuel gas is injected by the injector 10 in the overlap period. Can be stopped so that the unburned air-fuel mixture is not discharged as it is, so that fuel efficiency can be improved.
[0022]
(Embodiments of the Inventions of Claims 1 to 6)
Next, a control method for more appropriately starting the gas engine 100 will be described. FIG. 2 is a graph showing the relationship between the engine speed and the fuel gas injection amount when the gas engine 100 according to the first to seventh aspects of the present invention is started (until the rated speed is reached).
[0023]
From the start of the engine (A) (at the start of cranking) to the completion of the pre-purge (in the fuel gas supply passages 12 and 15 for the main chamber and the sub chamber and the fuel supply gas passage 25), fuel injection from the injector 10 is performed. Absent. The timing at which the pre-purge is completed and the fuel injection by the injector 10 is started is defined as gas injection (A1) (FIG. 2). The injection of fuel from the injector 10 is started by opening the fuel cutoff electromagnetic valve 35 installed upstream of the fuel gas supply passage 25. The amount of fuel gas injected from the injector 10 (first fuel supply means) after the gas injection (A1) is reduced to a constant injection amount Q per cycle until the first explosion (B) occurs. ₁ Set to. However, immediately after the gas input (A1), the fuel gas is not filled 100% in the pipes on the downstream side of the fuel shutoff solenoid valve 37, so that the excess air ratio (main and sub chambers) is as shown in FIG. Follow a history. The first explosion (B) occurs when the excess air ratio of the air-fuel mixture in the sub-chamber 5 reaches a value at which it is finally ignited and burned by the discharge of the spark plug 19.
[0024]
Adjustment of the fuel injection amount by the injector 10 can be performed by adjusting the pressure in the main chamber fuel gas supply passage 12 by the regulator 13 and adjusting the open period of the injector 10 per cycle. Further, in the present invention (the present embodiment), the fuel injection amount means the fuel amount injected per cycle.
[0025]
At the time of starting the engine (A), the solenoid valve 16 is closed, and the supply of the fuel gas to the sub chamber 5 via the sub chamber fuel gas supply passage 15 is stopped. After the gas input (A1), the fuel gas is supplied to the sub-chamber 5 via the main chamber 2, and the excess air ratio of the air-fuel mixture in the sub-chamber 5 eventually becomes the excess air ratio that can be ignited by the spark plug 19. The first explosion (B) occurs.
[0026]
When the first explosion (B) occurs, the engine speed rises to the right as shown in the graph of FIG. Until the engine speed reaches a preset primary speed (C) (first engine speed), the amount of fuel gas injected by the injector 10 is kept constant (injection amount Q1) by the controller 22.
[0027]
As the air flow rate per cycle decreases as the engine speed increases, the engine speed before the misfire occurs due to the excess air ratio in the sub-chamber 5 being too biased toward the rich side (rich side). It is set in advance as a number (C) (first engine speed). In the present invention, the excess air ratio is not actually measured, but is treated as being rich when the fuel injection amount increases and lean when the fuel injection amount decreases. The engine speed detector 21 detects that the engine speed has reached the primary speed (C), and when the controller 22 receives this detection signal, the controller 22 sends a signal to the injector 10, and the main The amount of fuel gas injected into the chamber 2 is reduced. When the engine speed reaches the engine speed (D), the controller 22 sends an open signal to the solenoid valve 16, and the fuel gas regulated by the regulator 17 is supplied to the check valve on the way through the sub chamber fuel gas supply passage 15. 18 is opened by pressing, and is directly supplied into the sub chamber 5 (second fuel supply means).
[0028]
Therefore, the excess air ratio in the sub chamber 5 after the rotation speed (D) gradually becomes rich (rich). The primary rotation speed (C) is preferably set within a range of 50 to 80% of the rated rotation speed. Further, the rotation speed (D) is preferably set within a range of about 100 to 120% of the primary rotation speed (C).
[0029]
The amount of fuel gas supplied to the main chamber 2 (the injection amount Q1) until the engine speed reaches the primary speed is caused by a small inertia force (particularly at a low speed immediately after the engine is started). Controller 22 operates the injector 10 such that the amount of fuel gas required when the gas engine 100 is operated at the rated speed with no load is about 1 to 4 times the amount of fuel gas. It is preferred that
[0030]
After the rotation speed (D), the excess air ratio in the sub-chamber 5 becomes rich irrespective of the excess air ratio in the main chamber 2, so that the combustion state in the sub-chamber 5 temporarily deteriorates and torque fluctuations occur. And the engine speed may fluctuate. At this time, if the fuel injection amount from the injector 10 (first fuel supply means) is under PID control, the fuel injection amount is further increased, and the excess air ratio in the sub chamber 5 is further shifted to the rich side. In the worst case, a misfire can occur. Therefore, immediately after the fuel supply (second fuel supply means) to the sub-chamber 5 via the sub-chamber fuel gas supply passage 15 is started (in FIG. 2, the primary rotation speed (C) to the secondary rotation speed (E)). During the period, it is preferable that the fuel injection amount by the injector 10 be subjected to MAP control set in advance to prevent the excess air rate in the sub chamber 5 from deviating from the flammable range.
[0031]
Further, it is preferable that the higher the lubricating oil temperature detected by the temperature detector 24 is, the smaller the amount of fuel supplied by the injector 10 is, and the more preferable the supply of the fuel gas to the main chamber 2 corresponding to the lubricating oil temperature is. When the map of the amount is stored in the memory 29 and the controller 22 controls the injector 10 according to the map, the startability of the gas engine 100 is improved.
[0032]
FIG. 4 is a graph showing the ratio of the fuel injection amount (per cycle) injected from the injector 10 corresponding to the lubricating oil temperature detected by the temperature detector 24. The temperature of the gas engine 100 at the time of starting varies depending on the season (particularly in summer and winter), and the lubricating oil temperature when the operating gas engine 100 is stopped and restarted before heat radiation proceeds is considerably high. The higher the temperature of the gas engine 100, the lower the viscosity resistance of the lubricating oil and the better the startability. Therefore, the lower the temperature of the lubricating oil (the temperature of the gas engine 100), the greater the fuel injection amount, and the higher the engine speed. Preferably, the number quickly reaches the rated speed.
[0033]
However, if the excess air ratio is remarkably biased toward the rich side, the flammable range will be deviated, and harmful components such as CO and HC contained in the exhaust gas will increase. For example, as shown in FIG. Assuming that the fuel injection amount at 60 ° C. is 60, the fuel injection amount is increased at a constant rate between 0 ° C. and 50 ° C. as the lubricating oil temperature decreases, so that the fuel injection amount becomes 100 at 0 ° C.
[0034]
The fuel gas continues to be directly supplied into the sub-chamber 5 and the excess air ratio in the sub-chamber 5 gradually becomes rich, and the predetermined engine speed before the misfire is caused to reach the secondary engine speed (E) (second engine speed) ) Is stored in the memory 29 in advance. Until the engine speed reaches the secondary speed from the primary speed, the MAP control by the controller 22 is performed on the gas engine 100, and the excess air ratio in the main chamber 2 is adjusted by the MAP control. Has become. When the engine speed reaches the secondary speed (E), the controller 22 switches from the MAP control to the PID control based on the difference between the actual speed and the target speed, and controls the fuel so that the engine speed quickly reaches the rated speed. Adjust the injection amount. Here, the secondary rotation speed (E) is preferably set to about 130% of the primary rotation speed (C).
[0035]
FIG. 3 is a graph showing the relationship between the fuel injection period and the engine speed when the invention of claim 6 is carried out. In FIG. 3, a shorter fuel gas injection period means that the fuel gas injection amount decreases. In order to avoid misfire due to excessive air concentration, the engine speed is set to the primary speed (for example, 800 min shown in FIG. 3). ^-1 ), The injection amount of the fuel gas from the injector 10 is gradually reduced, and the engine speed (the speed (D) in FIG. 2) is 940 min. ^-1 Then, the fuel gas is directly supplied to the sub-chamber 5 via the sub-chamber fuel gas supply passage 15, and the secondary rotation speed (E) is 1000 min. ^-1 Thereafter, the control is switched from the MAP control to the PID control.
[0036]
In the PID control, the fuel injection amount of the injector 10 is set based on the deviation between the actual rotation speed and the target rotation speed. A map for setting a target rotation speed capable of avoiding engine stall and overshoot is prepared in advance in the memory 29 ( The controller 22 performs PID control according to this map. The target rotation speed in this map is variable up to the rotation speed (F), but after reaching the rotation speed (F), the target rotation speed becomes the rated rotation speed (constant).
[0037]
From the low rotation speed to the rated rotation speed, the air flow rate in the air supply passage 3 is unstable, and when the control for adjusting the opening of the throttle valve 7 (the adjustment valve shown in FIG. 1) is further performed, The flow rate of the air supplied to the main chamber 2 becomes unstable. Therefore, according to the first to sixth aspects of the present invention, the opening of the throttle valve 7 is fixed (unchanged) until the engine speed reaches the rated speed, and the fluctuation of the air flow rate is minimized. preferable.
[0038]
(Embodiment of Claim 7)
FIG. 5 is a graph showing the range of the throttle opening when the invention of claim 7 is carried out. At the start of the cell (at the start of cranking or at the start of the engine), the opening of the throttle valve 7 (adjustment valve) is set within the range of 30 to 50% as shown in FIG. Then, the opening degree of the throttle valve 7 is gradually increased by the actuator 8 to which the signal is transmitted from the controller 22, so that the throttle valve 7 is fully opened after the engine speed reaches the primary speed. By adjusting the opening degree of the throttle valve 7 in this manner, the amount of air supplied per cycle until the first explosion (B) occurs can be reduced as much as possible, thereby reducing the excess air rate in the sub-chamber 5. The time required to reach the flammable range can be reduced, that is, the time required until the first explosion (B) can be reduced. Furthermore, after the engine speed reaches the primary speed (C), setting the opening to full open allows the air flow rate per cycle to be increased, and more fuel to be burned. It is possible to shorten the time required to reach the rated speed while performing stable combustion.
[0039]
The inventions of claims 1 to 7 described above can be applied to any of a supercharged gas engine and a non-supercharged gas engine. Although FIG. 1 shows the sub-chamber type gas engine 100, the inventions of claims 1 to 3, 6, and 7 can also be implemented for a single-chamber type gas engine without the sub-chamber 5.
[0040]
【The invention's effect】
In the invention of claim 1, an injector 10 (fuel supply means) is provided in the air supply passage 3 near the main chamber 2 (combustion chamber), and a controller 22 (PID control means) for controlling the amount of fuel gas injected by the injector 10 is provided. ), The excess air ratio in the main chamber 2 (combustion chamber) can be changed with good responsiveness, and the engine stall due to the excess air ratio in the main chamber 2 (combustion chamber) deviating from the flammable range. And overshoot exceeding the rated rotation speed can be avoided.
[0041]
After starting the engine, in the process of raising the engine speed to the rated speed, engine stall due to misfire can be avoided, and overshoot at the time of reaching the rated speed can be reduced or made zero. The gas engine 100 can be safely operated.
[0042]
According to the second aspect of the present invention, the amount of fuel gas supplied to the air supply passage 3 per unit time from the start of cranking until the engine speed reaches 50% to 100% of the rated speed is kept constant. The fuel supply means is set such that the fuel supply amount is maintained at a value 1 to 4 times the fuel supply amount required when the gas engine 100 is operated at the no-load rated rotation speed (fuel injection from the injector 10). Since the amount is adjusted by the controller 22, it is possible to obtain an effect more than that of the first aspect of the present invention.
[0043]
In the invention of claim 3, a temperature detector 24 (lubricating oil temperature detecting means) for detecting the temperature of the lubricating oil that cools each part of the gas engine 100 is provided, and as the lubricating oil temperature detected by the temperature detector 24 increases, the temperature increases. Since the fuel supply means is set so as to reduce the fuel supply amount (the fuel injection amount from the injector 10 is adjusted by the controller 22), it is possible to obtain the effect more than the invention of claim 1.
[0044]
According to the invention of claim 4, in the sub-chamber type gas engine 100, after starting the gas engine 100, the engine speed is quickly increased to the rated speed while avoiding engine stall due to misfire and overshoot exceeding the rated speed. Since it can be reached, a safe and quick start can be performed.
[0045]
When the PID control of the engine speed is performed after the gas injection (A1) as in the conventional gas engine, the operating environment of the gas engine differs depending on the temperature, lubricating oil temperature, etc., and a plurality of maps are prepared to set the target engine speed. The selection of an appropriate map can complicate the system. Unless this complicated system is prepared, the PID control based on the deviation between the actual engine speed and the target engine speed requires an engine. It is difficult to do this while avoiding stalls.
[0046]
However, according to the invention of claim 4, the predetermined engine speed before deviating from the flammable range due to the excessive air ratio in the sub-chamber 5 becomes the primary speed (C) (first engine speed). The PID control is not performed until the engine speed reaches the primary speed (C), and the PID control is performed after the engine speed reaches the primary speed (C). Can be stabilized.
[0047]
The effect that the PID control is not performed until the engine rotation speed reaches the primary rotation speed (C) and the PID control is performed after the engine rotation speed reaches the primary rotation speed (C) is also achieved in the invention of claim 1. Can play.
[0048]
According to the fifth aspect of the present invention, the secondary rotational speed (E) (second engine rotational speed) is set between the engine rotational speed of 120% of the primary rotational speed and the rated rotational speed, and the secondary fuel supply means sets the secondary rotational speed (E). Immediately after the fuel supply to the sub-chamber 5 via the fuel gas supply passage 15 for the room is started, the MAP control of the fuel injection amount by the injector 10 is performed based on the MAP in which the optimum target rotation speed with respect to the actual rotation speed is set. As a result, the excess air ratio in the sub-chamber 5 can be prevented from deviating from the flammable range, and the engine speed can quickly reach the rated speed. It can be carried out.
[0049]
When the invention of claim 6 is implemented, overshoot when the engine speed reaches the rated speed can be reliably prevented, so that the safety of the gas engine 100 can be improved.
[0050]
According to the seventh aspect of the invention, by controlling the supply of air to the combustion chamber 2 (main chamber) with a throttle, the time from the gas input (A1) to the first explosion (B) can be shortened. Since the engine is set to be fully opened after the engine speed reaches the primary speed (C), the time required to reach the rated speed can be reduced while performing stable combustion.
[0051]
In the present invention (inventions of claims 1 to 7), the primary rotational speed (C), which did not exist even in the conventional concept, is found and set, and in PID control, the engine rotational speed is set to the primary rotational speed (C). , It is possible to provide good startability in various operating environments of the gas engine.
[Brief description of the drawings]
FIG. 1 is a system schematic diagram of a gas engine for carrying out the inventions of claims 1 to 7;
FIG. 2 is a graph showing the relationship between the engine speed and the fuel gas injection amount when the gas engine according to the first to seventh aspects of the present invention is started (until the rated speed is reached).
FIG. 3 is a graph showing a comparison between a fuel injection period immediately after engine start and an engine speed when the invention of claim 6 is implemented.
FIG. 4 is a graph showing a ratio of a fuel injection amount corresponding to a lubricating oil temperature when the invention of claim 3 is implemented.
FIG. 5 is a graph showing the relationship between the time required for the first explosion and the throttle opening when the invention of claim 7 is carried out.
FIG. 6 is a schematic system diagram showing a flow path of air and fuel gas of an AYG type gas engine which is an embodiment of the present invention.
FIG. 7 is a schematic system diagram showing a flow path of air and fuel gas of a conventional NHLG-type gas engine.
[Explanation of symbols]
1 Engine body
2 Main room (combustion chamber)
3 Air supply passage
4 Exhaust passage
5 Vice room
6 Turbocharger
6a Compressor section
6b Turbine section
7 Throttle valve
8 Actuator
9 Intercooler
10. Injector (fuel supply means, first fuel supply means)
11 Intake port
12 Fuel gas supply passage for main room
13 Regulator
14 Gas compressor
15 Fuel gas supply passage for sub chamber
16 Solenoid valve
17 Regulator
18 Check valve
19 Ignition plug
20 flywheel
21 Engine speed detector
22 Controller
23 Lubricating oil cooler
24 Temperature detector (lubricating oil temperature detecting means)
25 Fuel gas supply passage
26 Intake valve
27 Exhaust valve
28 Exhaust port
29 memory (storage means)
30-36 signal line
37 Solenoid valve for fuel cutoff
100 gas engine

Claims (7)

Fuel supply means for supplying fuel near the combustion chamber of the air supply passage for supplying air to the combustion chamber,
PID control means for adjusting an amount of fuel supplied by the fuel supply means so as to avoid an engine stall caused by an excess air ratio in the combustion chamber deviating from a flammable range and an overshoot exceeding a rated speed,
When the engine speed reaches a predetermined first engine speed before deviating from the flammable range due to an excessive air ratio in the combustion chamber,
A gas engine equipped with a control mechanism for a fuel injection amount at the time of starting, wherein an engine speed is quickly brought close to a rated speed by adjusting a fuel supply amount by the PID control means. The fuel supply amount per cycle by the fuel supply means from the start of cranking until the engine speed reaches within the range of 50 to 100% of the rated speed is kept constant, and the fuel supply amount is maintained at no load. 2. The gas engine according to claim 1, wherein the control unit controls the fuel injection amount at the time of starting according to claim 1, wherein the fuel supply amount is set to be one to four times a fuel supply amount required when the engine is operated at the rated speed. Lubricating oil temperature detecting means for detecting the temperature of the lubricating oil for cooling each part of the gas engine is provided, and as the lubricating oil temperature detected by the lubricating oil temperature detecting means increases, the fuel supply amount per cycle decreases. 2. A gas engine comprising a control mechanism for controlling a fuel injection amount at the time of starting according to claim 1, wherein the gas supply means is set. In a gas engine having a main chamber and a sub-chamber, a first fuel supply means for supplying fuel is provided near an air supply passage for supplying air to the main chamber near the main chamber. Providing second fuel supply means for supplying fuel;
PID control execution means for adjusting an amount of fuel supplied by the first fuel supply means so as to avoid an engine stall caused by an excess air ratio in the main chamber deviating from a flammable range and an overshoot exceeding a rated speed. Prepare,
After the engine speed reaches a predetermined first engine speed before it deviates from the flammable range due to an excessive air ratio in the sub-chamber, the second fuel supply means supplies fuel to the sub-chamber. A gas engine provided with a control mechanism for a fuel injection amount at the time of starting, wherein the engine speed is started to quickly reach a rated speed. An engine speed at which fuel supply to the sub chamber by the second fuel supply means is started is set within a range of 100 to 120% of the first engine speed, and the first engine speed is reduced from the first engine speed. Between the second engine speed set within the range of 120% of the engine speed to the rated engine speed, the adjustment of the fuel injection amount by the first fuel supply means is performed by MAP control in which a target value is set in advance, and the engine speed is quickly increased. 5. The gas engine according to claim 4, wherein the engine speed is set close to the rated engine speed. After the engine speed reaches the second engine speed set within the range of 120% of the first engine speed to the rated engine speed, the fuel supply amount by the fuel supply means or the first fuel supply means is determined by PID. 5. The gas engine according to claim 1, further comprising storage means for storing a target engine speed for control. The opening of the regulating valve for adjusting the amount of air supplied to the combustion chamber or the main chamber at the time of starting the cell is set within a range of 30 to 50%, and the opening of the regulating valve increases as the engine speed increases. The fuel injection amount control mechanism at the time of starting according to claim 1 or 4, wherein the control mechanism is set so as to be large and is set to be fully opened after the engine speed reaches the first engine speed. Gas engine.

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