JPH05164002A - Fuel controller of stationary type gas engine - Google Patents

Abstract

PURPOSE:To increase fuel according to a larger load than the load when a throttle valve is fully opened, in the engine in which fuel is supplied according to the engine negative pressure corresponding to the opening degree of the throttle valve. CONSTITUTION:In a stationary type lean-burn gas engine 1 in which gas fuel is supplied through a main fuel supply passage 9 according to the negative pressure of the engine, a sub-fuel supply passage 12 bypassing the main fuel supply passage 9, the fuel correcting valve 13 providing in the sub-fuel supply passage 12, and a fuel correction valve actuating means, which opens the fuel correction valve 13 when an engine load of a normal load or larger load is acted on the engine 1, are provided. When an engine load exceeds a normal load, in addition to the main fuel passage 9, fuel is supplied from the sub-fuel passage 12, too.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel control device for a stationary gas engine.

[0002]

2. Description of the Related Art In a recent heat pump type air conditioning system for buildings, an air compressor of an outdoor unit for an air conditioner is driven by a stationary gas engine using a gas fuel such as LNG or LPG from the viewpoint of power saving. Is performed (for example, Japanese Patent Laid-Open No. 2-1
No. 02332).

In a stationary gas fuel engine used for driving such an air compressor, the air-fuel ratio A / F of the engine is generally set from the viewpoints of both energy saving and exhaust pollution prevention (improvement of exhaust emission). A lean-burn method, which operates by setting an air-fuel ratio that is leaner than the original theoretical air-fuel ratio, is often adopted.

[0004]

By the way, in the recent air conditioning system for buildings as described above, a plurality of indoor units are operated by one large-capacity air compressor to air-condition each room. So-called multi-air conditioning systems have become mainstream. Therefore, the multi-air-conditioning system essentially has a characteristic that the load of the air compressor fluctuates with a considerable width depending on the number of indoor units.

On the other hand, the character of the air conditioning system is
Since continuous operation is inevitably performed for a long time, the performance of the engine itself that drives the air compressor tends to deteriorate with time. Therefore, due to the passage of operating time, even when the amount of fuel is the same, the maximum output gradually decreases, and it becomes practically impossible to meet the required output on the air compressor side, resulting in overload operation and stable operation. There is a possibility that a situation may occur in which the air compressor cannot be driven.

As a countermeasure against the above problems, for example, as is often found in automobile engines, in the above case, the microcomputer is used to perform feedback control corresponding to the above load fluctuations to control the air-fuel ratio. It is conceivable to make corrections or adopt methods such as making the base air-fuel ratio rich by learning control of the air-fuel ratio in response to deterioration over time, but from the viewpoint of low cost and maintenance-free No complicated and expensive control system can be adopted.

[0007]

The invention described in each of claims 1 to 3 of the present application was made for the purpose of solving the above problems, and is configured as follows. .

(1) Structure of the Invention According to Claim 1 In the fuel control device for a stationary gas engine according to claim 1, the gaseous fuel is supplied through the main fuel supply passage according to the engine negative pressure. In the lean-burn stationary gas engine, the auxiliary fuel supply passage bypassing the main fuel supply passage, the fuel correction valve provided in the auxiliary fuel supply passage, and the engine load higher than the normal load are applied to the engine. And a fuel correction valve operating means for opening the fuel correction valve when actuated. When the engine load exceeds the normal load, fuel is supplied from the auxiliary fuel supply passage in addition to the main fuel supply passage. It is characterized by doing so.

(2) Structure of the invention according to claim 2 The fuel control device for a stationary gas engine according to claim 2 is the fuel for a fuel control device for a stationary gas engine according to claim 1. The correction valve has a negative pressure introducing means for introducing a negative pressure of the engine, and the engine negative pressure introduced by the negative pressure introducing means becomes a negative pressure value exceeding a negative pressure value corresponding to a normal load of the engine. It is characterized in that the valve is opened by utilizing the negative pressure when the valve is opened.

(3) Configuration of the invention according to claim 3 The fuel control device for a stationary gas engine according to claim 3 is the same as the fuel control device for a stationary gas engine according to claim 1. The fuel correction valve is constituted by an electromagnetic valve, and the fuel correction valve actuating means further has engine negative pressure detecting means for detecting negative pressure of the engine, and the engine negative pressure detected by the engine negative pressure detecting means is When the negative pressure value exceeds the negative pressure value corresponding to the normal load of the engine, an electric valve opening signal is output to control the opening of the solenoid valve. .

[0011]

As a result of being configured as described above, the inventions according to claims 1 to 3 of the present application respectively have the following effects corresponding to the respective structures.

(1) Operation of the invention according to claim 1 In the fuel control device for a stationary gas engine according to claim 1, first, a gaseous fuel is supplied through a main fuel supply passage in accordance with an engine negative pressure, It is configured to perform lean combustion, has a sub fuel supply passage that bypasses the main fuel supply passage, and a fuel correction valve is provided in the sub fuel supply passage. Further, a fuel correction valve operating means for opening the fuel correction valve when an engine load higher than the normal load acts on the engine is provided, and when the load acting on the engine exceeds the normal load, the main load In addition to the fuel supply passage, the auxiliary fuel supply passage also supplies fuel to increase the amount of fuel to be supplied, thereby producing an output corresponding to a large load exceeding the normal load.

(2) Operation of the invention according to claim 2 In the fuel control device for a stationary gas engine according to claim 2, the same operation as the invention according to claim 1 is achieved based on its basic configuration. In addition, in this case, in particular, the fuel correction valve has negative pressure introducing means for directly introducing the negative pressure itself of the engine, and the engine negative pressure introduced by the negative pressure introducing means corresponds to the normal load of the engine. When the negative pressure value exceeds the negative pressure value, the negative pressure itself is used to open the valve.

Therefore, it is possible to realize fuel correction at low cost by mechanical means such as a diaphragm valve without using a microcomputer or electric boost pressure detecting means.

(3) Operation of the invention of claim 3 In the fuel control device for a stationary gas engine of the invention of claim 3, the operation of the invention of claim 1 is achieved based on its basic configuration. In this case, in particular, the fuel correction valve is constituted by an electromagnetic valve, and the fuel correction valve actuating means has an engine negative pressure detecting means for detecting negative pressure of the engine, which is detected by the engine negative pressure detecting means. When the engine negative pressure becomes a negative pressure value exceeding the negative pressure value corresponding to the normal load of the engine, an electric valve opening signal is output to control the opening of the solenoid valve. It requires a computer and a boost pressure sensor, but can respond to changes in engine boost pressure with good responsiveness to detect load fluctuations and overload conditions and perform appropriate fuel correction. And the control performance is high.

[0016]

Therefore, according to the present invention, the output can be corrected reliably and easily on the basis of the change in the engine boost pressure in response to the relative overload state due to the fluctuation of the external load of the engine and the deterioration of the engine itself. In each of these cases, a stable operating state can be maintained.

[0017]

【Example】

(1) First Embodiment FIGS. 1 and 2 show a fuel control device for a stationary gas engine according to a first embodiment of the present invention. FIG. 1 is a schematic view of a fuel control system for the device according to the first embodiment. 2 and 3 are control area diagrams of the apparatus.

First, the schematic structure and control function of the fuel control system of the present embodiment will be described with reference to FIG. 1, and then the control operation of the main part will be described with reference to the characteristics of FIG.

In FIG. 1, reference numeral 1 is an engine main body, and intake air into the engine main body 1 is sucked from the atmosphere through an air funnel 2 portion, and thereafter, a mixer portion 5, a throttle valve 3 and an intake port 4 are provided. After that, the air-fuel mixture of a predetermined A / F is supplied to the in-cylinder engine combustion chamber 8. Also, the gaseous fuel (LPG,
LNG) is from the fuel tank (not shown) to the main fuel supply passage 9
First, the main jet portion 6a at the downstream end of the main fuel supply passage 9 is supplied to the main nozzle portion 5a of the mixer portion 5, and the fuel ejected from the main nozzle portion 5a is supplied from the air funnel 2 side. It is effectively mixed with intake air and supplied into the engine combustion chamber 8 through the intake port 4 as described above. A zero governor 11 for adjusting the fuel pressure for adjusting the pressure of the fuel to the atmospheric pressure level is provided in the middle of the main fuel supply passage 9.

Further, reference numeral 12 is the main fuel supply passage 9 described above.
Is a sub-fuel supply passage branched from the middle of, and its downstream side is communicated with the second nozzle portion 5b of the mixer portion 5 via the fuel correction valve 13 and the sub-jet portion 6b,
When the fuel correction valve 13 is opened, a predetermined amount of correction fuel is supplied to the engine as in the case of the main fuel supply passage 9.

The fuel correction valve 13 is provided with, for example, an actuator of a diaphragm type which receives a valve closing biasing force of a predetermined pressure by a spring, and the negative pressure chamber side of the actuator is connected to the intake passage 7 via a negative pressure passage 14. The structure is such that the throttle valve 3 is communicated with the downstream side, and the boost pressure (load R) of the engine is larger than a predetermined set pressure value (100% line in FIG. 2 = determination standard) (load R = 101- It will be opened when it reaches 120%). The above set pressure is
When the manufacturing of the gas engine is completed (when it is new), it is under a lean fuel amount determined by the throttle amount of the main jet 6a, and corresponds to WOT when the throttle valve 3 is fully opened. Then, the amount of the intake air-fuel mixture into the in-cylinder combustion chamber 8 during engine operation is controlled by the throttle valve 3. The throttle valve 3
It is operated by the stepping motor 16 controlled by the engine control unit 22 and is maintained at the minimum opening state in the idle operation state. Reference numeral 10 is an exhaust pipe.

Further, reference numeral 17 designates the engine body 1 described above.
Is a spark plug provided in the cylinder head portion of the engine, and a predetermined ignition voltage is applied to the spark plug 17 through a distributor and an igniter (not shown). The timing is controlled by an ignition timing control signal supplied from the engine control unit 22 to the igniter.

Therefore, according to the above configuration, first, in the normal range up to 100% of the engine load of FIG. 2, the main fuel supply passage 9 is changed according to the engine negative pressure which changes according to the throttle opening.
Gas fuel is supplied through the main fuel jet passage 6a so as to perform lean combustion at an A / F determined in advance by the diameter of the main jet 6a, while the sub fuel that bypasses the main fuel supply passage 9 is supplied. It has a supply passage 12, and a fuel correction valve 13 is provided in the sub fuel supply passage 12. In addition to the above configuration, the engine load (101 to 12) exceeding 100% of the maximum value of the normal load is applied to the engine.
(0%) is actuated, fuel compensation valve operating means (diaphragm and negative pressure passage) for opening the fuel compensation valve 13 is provided, and when the load acting on the engine exceeds the normal load, the main fuel In addition to the supply of fuel from the supply passage 9, the fuel is also supplied from the auxiliary fuel supply passage 12 to increase the amount of supplied fuel and output corresponding to the increased load.

Moreover, in this case, in particular, as described above, the fuel correction valve 13 and its operating means have the negative pressure introducing passage 14 for directly introducing the negative pressure of the engine itself, and the negative pressure introducing passage 14 introduces the negative pressure. When the engine negative pressure reaches a negative pressure value exceeding the negative pressure value corresponding to the normal load of the engine, the negative pressure itself is used to open the valve.

Therefore, fuel correction can be realized at low cost by mechanical means such as a diaphragm valve without using a microcomputer or electric boost pressure detecting means.

As a result, even if a relative overload condition occurs due to fluctuations in the external load of the engine or deterioration of the engine itself over time, the output can be corrected reliably and easily based on changes in the engine boost pressure. In each of these cases, a stable operating state can be maintained.

(2) Second Embodiment Next, referring to FIGS. 3 and 4, an electromagnetic solenoid type opening / closing valve is used as a fuel correction valve 21 in place of the negative pressure-operated mechanical fuel correction valve 13 described above. A second embodiment of the present invention in which a fuel correction valve 21 including the solenoid type opening / closing valve is electrically controlled to be opened / closed by an engine control unit 22 based on an engine boost pressure detected by an engine boost pressure sensor 20. It shows the configuration and operation of the fuel control device of such a stationary gas engine.

Next, the engine control unit 2
The fuel correction control of this embodiment using 2 will be described in detail with reference to the flowchart of FIG.

That is, first, in step S ₁ , the engine is started to drive the above-mentioned air compressor for the multi-type air conditioning system.

Then, in step S ₂ , it is determined whether the engine is in the load operation state in the air compressor drive state. In the determination of the load operating state, under the rated operating state of the engine, the current engine maximum output (throttle) is compared with the required output from the air compressor side based on the engine boost pressure detected by the engine boost pressure sensor 20. (Fully open output) is still operating with a margin (required output: within the maximum output), or the maximum output is smaller than the required output.
Judge whether it is operating at (required output: maximum output or more).

As a result, when the operation is in a state in which the output higher than the required output can be output by opening the throttle valve ₃ , the process proceeds to step S ₃ and the lean fuel amount originally set is set. Low-emission mode operation (economy mode). On the other hand, when the required output on the air compressor side, which cannot be dealt with by opening the throttle valve 3, is higher than the current maximum output of the engine in the overload operation state, the routine proceeds to step S ₆ and the electromagnetic solenoid type The fuel correction valve 21 including the open / close valve is controlled to open. And, thereby the fuel is supplied from the main fuel supply passage 9 in addition to the supply of the fuel secondary fuel supply passage 12 from sufficiently up the engine output by increasing the fuel supply amount of the total power of the step S ₆ Perform mode operation. As a result, it is possible to operate with a margin corresponding to the required output of the air compressor.

On the other hand, when the low emission mode operation of step S ₃ (economy mode operation) and the power mode operation of step S ₇ are respectively performed as described above,
Further, in steps S ₄ and S ₈ , the fluctuation of the load on the air compressor side (change in the number of operating indoor units) is similarly determined.

First, if the result of the load change determination in step S ₄ is that there is no load change or the maximum engine output, which is a change in the decreasing direction even if there is a load change, is greater than the required output. In step S ₅ , the low emission mode operation with the lean fuel amount is continued as it is. On the other hand,
In overload operation state in step S ₁₀ the required output load is increased began to exceed the maximum output of the engine,
Proceed to Step S ₆ to S ₇ described above, performs fuel increase by up engine output performing power mode operation. As a result, it is possible to secure a high output corresponding to the above load fluctuation (increase in the number of operating indoor units).

On the other hand, regardless of whether the power mode operation in step S ₇ is from step S ₂ or step S ₁₀ , step each further determined load change S _8, when a new overload condition has increased load or the step S ₄ is continued, step S ₉
The above step S ₆ in perform the power mode set again,
Continue the output up operation of S ₇ .

On the other hand, contrary to the above, the load amount decreases (the number of operating indoor units decreases) and the required output on the air compressor side decreases, and the required output is the maximum output at the set lean fuel amount of the engine. when is within proceeds to step S ₁₂ to close the fuel correction valve 21 in step S _11, performs low emissions mode operation at the set lean fuel quantity only from the main fuel supply passage 9 side.

Therefore, according to the structure of the first embodiment as well, by merely adopting the electromagnetic solenoid valve as the fuel correction valve and adding the engine boost pressure sensor, it is possible to obtain the same effect as that of the first embodiment. You can do it.

In the above embodiment, the case where the external load of the engine is the air compressor has been described as an example, but it goes without saying that the load is not limited to the air compressor.

[Brief description of drawings]

FIG. 1 is a fuel control system diagram showing a configuration of a fuel control device for a stationary gas engine according to an embodiment of the present invention.

FIG. 2 is a diagram showing a control area of the apparatus.

FIG. 3 is a fuel control system diagram showing a configuration of a fuel control device for a stationary gas engine according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing a fuel control operation of the device.

[Explanation of symbols]

1 is an engine body, 2 is an air funnel, 3 is a throttle valve, 5 is a mixer section (fuel mixing section), 7 is an intake passage, 8
Is an engine combustion chamber, 9 is a main fuel supply passage, 12 is a sub fuel supply passage, 13 and 21 are fuel correction valves, 14 is a negative pressure passage,
Reference numeral 20 is an engine boost pressure sensor, and 22 is an engine control unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Kato 2-4-1 Niho, Minami-ku, Hiroshima City Mazda Industrial Co., Ltd. (72) Fumiko Matsushita 2-4-1 Niho, Minami-ku, Hiroshima Mazda Within Industry Co., Ltd.

Claims (3)

[Claims] 1. A stationary combustion gas engine of a lean-burn system in which gaseous fuel is supplied through a main fuel supply passage in accordance with engine negative pressure, and a sub-fuel supply passage bypassing the main fuel supply passage, A fuel correction valve provided in the sub fuel supply passage and a fuel correction valve operating means for opening the fuel correction valve when an engine load higher than the normal load acts on the engine are provided, and the engine load is set to the normal load. A fuel control device for a stationary gas engine, characterized in that, when it exceeds, the fuel is supplied from the auxiliary fuel supply passage in addition to the main fuel supply passage. 2. The fuel correction valve actuating means has negative pressure introducing means for introducing negative pressure of the engine, and the engine negative pressure introduced by the negative pressure introducing means corresponds to a normal load of the engine. 2. The fuel control device for a stationary gas engine according to claim 1, wherein when the negative pressure value exceeds the pressure value, the negative pressure is utilized to open the fuel correction valve. 3. The fuel correction valve is constituted by an electromagnetic valve, and the fuel correction valve actuating means has an engine negative pressure detecting means for detecting negative pressure of the engine, and the fuel pressure is detected by the engine negative pressure detecting means. When the engine negative pressure becomes a negative pressure value exceeding the negative pressure value corresponding to the normal load of the engine, an electric valve opening signal is output to control the opening of the solenoid valve. Claim 1 characterized by
A fuel control device for a stationary gas engine as described.