JPH0627824Y2 - Pilot fuel injection valve malfunction detection device for gas-fired internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a pilot fuel injection valve malfunction detection device for monitoring the operating state of a pilot fuel injection valve in a gas-fired internal combustion engine.

[Conventional technology]

Generally, in a gas-fired internal combustion engine, in addition to combustible gas, fuel oil (pilot fuel) is injected from a pilot fuel injection valve into a cylinder in order to assist ignition of the gas.

The following two are major problems with such a pilot fuel injection valve.

(1) The needle valve in the pilot fuel injection valve becomes stuck during the lift, the pilot fuel flow path remains open, the pilot fuel continues to flow out from the injection valve, and the pressure of the pilot fuel decreases. When the spray condition deteriorates significantly.

(2) When the pilot fuel is not injected into the cylinder due to stick trouble of the injection pump for supplying pilot fuel to the injection valve or trouble of pump rack position control.

Even if any of the above-mentioned troubles occurs, there is a case where a flammable gas is discharged to the outside of the cylinder without igniting and reaches the exhaust collecting pipe. In this case, there is a risk that the sparks, etc. discharged from the other cylinder to the exhaust collecting pipe will become the ignition source, and the unignited flammable gas will cause an explosion in the exhaust collecting pipe, resulting in significant damage to the components of the engine. .

Therefore, as means for preventing such a problem, conventionally, unburned gas in the exhaust gas at the cylinder outlet pipe is detected, exhaust gas temperature is monitored, pilot fuel oil pressure is monitored, etc. A means for detecting is proposed and practiced.

[Problems to be solved by the invention]

However, in the above-mentioned conventional pilot fuel injection valve malfunction detection means for a gas-fired internal combustion engine, malfunction of the pilot fuel injection valve can be detected only by an indirect phenomenon. There is a problem in that it takes time from the time of occurrence of a defect to the inspection, and it is not possible to reliably detect a malfunction.

The present invention is intended to solve such a problem, and it is possible to detect a malfunction of the pilot fuel injection valve directly from the operating state of the needle valve of the same, thereby preventing a trouble in the pilot fuel injection valve. It is an object of the present invention to provide a pilot fuel injection valve malfunction detection device for a gas-fired internal combustion engine, which is capable of promptly and reliably notifying that the safety is improved during operation of the gas-fired internal combustion engine.

[Means for solving problems]

Therefore, the pilot fuel injection valve malfunction detection device for a gas-fired internal combustion engine of the present invention, in a gas-fired internal combustion engine having a pilot fuel injection valve, a pulse generator that generates a pulse signal in synchronization with the crank angle of the engine, The pilot fuel injection valve includes a lift sensor that detects a lift amount of a needle valve, and a calculator that receives a pulse signal from the pulse generator and a needle valve lift detection signal from the lift sensor. With the function of detecting malfunction of the pilot fuel injection valve by comparing the needle lift detection signal from the lift sensor before and after the injection period of the fuel injection valve and the maximum lift amount during the same period, It is characterized in that a safety mechanism that operates upon receiving a detection signal from the arithmetic unit is provided.

[Action]

In the above-described device for detecting malfunction of the pilot fuel injection valve for the gas-fired internal combustion engine of the present invention, when the pilot fuel injection valve causes a stick, the lift amount of the needle valve detected by the lift sensor before and after the injection period of the injection valve. However, the operation failure of the pilot fuel injection valve is detected by comparing and detecting the difference in the arithmetic unit, and the safety mechanism operates in response to the detection signal from the arithmetic unit.

Further, when the pilot fuel injection valve does not operate, the lift amount of the needle valve before the injection period of the injection valve and the maximum lift amount during the injection period match, and the matching of the lift amounts is compared in the calculator. By detecting the operation failure of the pilot fuel injection valve, the safety mechanism operates in response to the detection signal from the computing unit.

〔Example〕

A pilot fuel injection valve malfunction detection device for a gas-fired internal combustion engine as an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram thereof, and FIG. FIG. 3 is a graph for explaining the operation of the present device when a stick or the like malfunctions, and FIG. 3 is a graph for explaining the operation of the present device when pilot fuel is not injected due to a trouble in the pilot fuel injection system. is there.

As shown in FIG. 1, in a gas-fired internal combustion engine having a pilot fuel injection valve 1, a needle valve 1a for controlling injection of pilot fuel of the pilot fuel injection valve 1 is
A lift sensor 2 for detecting the lift amount of 1a is attached, and this lift sensor 2 is
It is connected to a CPU 5 as an arithmetic unit via an amplifier 3 and an A / D converter 4 for amplifying the detection signal from.

On the other hand, the engine is provided with a pulse generator 6 that generates a pulse signal in synchronization with the crank angle of the engine, and the pulse generator 6 is also connected to the CPU 5 to output the pulse signal to the CPU 5.

The pulse generator 6 generates pulse signals of several waves (T / Δt) at intervals Δt during the injection period T of the pilot fuel injection valve 1 in one cycle, as shown in FIGS. Thus, the timing is adjusted so that the pulse signal is output for each approximately 1 to 2 crank angles.

The CPU 5 then generates the first and last pulse signals of the injection period T of the pilot fuel injection valve 1 (t ₁ and
t _2, or t ₃ and t _4), the lift amount detection signal of the needle valve 1a detected by the lift sensor 2, thereby to transfer memory A and B in each storage unit 7 stores. At the same time, the CPU 5 detects the maximum lift amount of the needle valve 1a detected by the lift sensor 2 during the injection period T in which the pulse signal is generated, and transfers it to the memory C in the storage unit 7 for storage. .

Immediately thereafter, the CPU 5 compares the magnitudes of the stored signals of the memories A and B, and when the difference is larger than the set value, transmits the alarm signal to the safety mechanism 8 (mechanism for shutting off the fuel gas). On the other hand, the magnitudes of the stored signals in the memories A and C are compared, and if the difference is less than the set value, the alarm signal is transmitted to the safety mechanism 8.

After the comparison, the storage signal in the memory C is reset every cycle.

Since the pilot fuel injection valve malfunction detection device for a gas-fired internal combustion engine as one embodiment of the present invention is configured as described above, this device is used when the pilot fuel injection valve 1 malfunctions such as a stick. To explain the process of detecting the malfunction, as shown in FIG. 2, the movement of the needle valve 1a is normal in the first cycle in FIG. 2 and no alarm signal is generated, but in the second cycle. The stick phenomenon occurs while the needle valve 1a is sitting.

Due to this, the magnitudes of the memory signals of memories A and B are different,
When this difference is detected by the CPU 5 and detected to be equal to or greater than the set value, an alarm signal is output to the safety mechanism 8 during the cycle in which this trouble has occurred.

On the other hand, when the pilot fuel is not injected due to a trouble in the pilot fuel system (injection pump, etc.), the process of detecting no injection by this device will be explained. As shown in FIG. 3, one cycle in FIG. With the eyes, the movement of the needle valve 1a is normal, and no alarm signal is generated. Then, after the comparison detection of the memories A and C in the first cycle, the storage signal is reset in the memory C, and the memory C is brought into a state ready for the next cycle.

In the second cycle, the pilot fuel injection valve 1 does not operate, and the stored values of the memory A and the memory C are the same. Therefore, the difference in the comparison detection result in the CPU 5 is less than or equal to the set value, and the CPU 5 outputs the alarm signal. 5 is a safety mechanism 8
Is output to.

Upon receiving the alarm signal, the safety mechanism 8 performs an engine stop operation such as shutting off the fuel gas.

In addition, TDC in FIGS. 2 and 3 indicates the top dead center time.

Thus, according to the present device, the pilot fuel injection valve 1
The detection signal of the lift sensor 2 of the needle valve 1a before and after the injection period T and the maximum lift amount during the same period T are compared and detected,
Since the malfunction of the pilot fuel injection valve 1 is detected, the zero-point output of the lift sensor 2 is not affected by drift due to temperature and the like, and the detection sensitivity can be easily set.

In addition, the needle valve is used to detect the malfunction of the pilot fuel injection valve 1.
Since it can be directly performed by 1a, the response is extremely fast compared to other means (gas sensor, monitoring of exhaust temperature, etc.), and it can respond effectively and promptly to secondary troubles such as abnormal combustion in the cylinder.

Further, since there is no treatment such as averaging the signal of the lift sensor 2 of the needle valve 1a over several cycles and the CPU 5 makes the judgment only by the signal within one cycle, it is possible to monitor the malfunction immediately after starting the engine. Is.

[Effect of device]

As described above in detail, according to the pilot fuel injection valve malfunction detection device for a gas-fired internal combustion engine of the present invention, in a gas-fired internal combustion engine having a pilot fuel injection valve, a pulse signal synchronized with the crank angle of the engine is provided. A pulse generator that generates, a lift sensor that detects the lift amount of the needle valve of the pilot fuel injection valve, and a calculator that receives a pulse signal from the pulse generator and a needle lift detection signal from the lift sensor,
A function of the arithmetic unit to detect malfunction of the pilot fuel injection valve by comparing the needle lift detection signal from the lift sensor before and after the injection period of the pilot fuel injection valve and the maximum lift amount during the same period. With a simple structure in which a safety mechanism that operates by receiving the detection signal from the same computing unit is set, it is possible to quickly and reliably monitor the malfunction of the pilot fuel injection valve immediately after the engine is started. The safety mechanism stops the engine in advance to prevent accidents such as unburned gas filling the engine and eventually exploding, so reliability and safety during operation of the gas-fired internal combustion engine are prevented. It is possible to secure the sex.

[Brief description of drawings]

1 to 3 show a pilot fuel injection valve malfunction detection device for a gas-fired internal combustion engine as an embodiment of the present invention. FIG. 1 is a schematic block diagram thereof, and FIG. 2 is pilot fuel. A graph for explaining the operation of the present device when the injection valve has a malfunction such as a stick.
The figure is a graph for explaining the operation of the present device when the pilot fuel is not injected due to a trouble of the pilot fuel injection valve. 1 ... Pilot fuel injection valve, 1a ... Needle valve, 2 ... Lift sensor, 3 ... Amplifier, 4 ... A / D converter, 5 ...
CPU as arithmetic unit, 6 ... Pulse generator, 7
...... Memory unit, 8 ... Safety mechanism, A, B, C ... Memory.

Claims (1)

[Scope of utility model registration request] 1. A gas-fired internal combustion engine having a pilot fuel injection valve, a pulse generator for generating a pulse signal synchronized with a crank angle of the engine, and a lift sensor for detecting a lift amount of a needle valve of the pilot fuel injection valve. And a calculator that receives a pulse signal from the pulse generator and a needle valve lift detection signal from the lift sensor, and the calculator is a needle from the lift sensor before and after the injection period of the pilot fuel injection valve. A function is set to detect a malfunction of the pilot fuel injection valve by comparing the valve lift detection signal and the maximum lift amount during the same period, and a safety mechanism that operates by receiving a detection signal from the same calculator is provided. A pilot fuel injection valve malfunction detection device for a gas-fired internal combustion engine.