KR20070109774A - Fuel supply method for gas engine and fuel injection control apparatus of gasoline substitute gas fuel - Google Patents

Abstract

A fuel supply method for a gas engine and an injection control apparatus of gas fuel substituting for gasoline are provided to achieve fuel injection control with proper injection timing by injecting the gas fuel using corrected delay time. A fuel supply method for a gas engine comprises a step of performing injection control of the gas fuel by using a plug representing if the gas fuel is injecting or is not injecting. When the plug represents that the gas fuel is not injecting at the time point at which injection start of a gasoline injection signal is detected, injection of the gas fuel starts by setting the plug representing that the gas fuel is injecting. When the plug represents that the gas fuel is injecting at the time point at which injection end of the gas fuel is detected, the plug representing that the gas fuel is not injecting is set.

Description

FUEL SUPPLY METHOD FOR GAS ENGINE AND FUEL INJECTION CONTROL APPARATUS OF GASOLINE SUBSTITUTE GAS FUEL}

1A and 1B are waveform diagrams showing a control state in the gasoline alternative gas fuel injection control apparatus according to the embodiment of the present invention.

2 (a) and 2 (b) are waveform diagrams showing a control state of a conventional gasoline alternative gas fuel injection control device.

FIG. 3 is a flowchart showing the operation of the fuel injection control device in the waveform diagrams of FIGS. 1A and 1B.

4 is a layout view of a fuel supply system common to the embodiment and the conventional example in the present invention.

FIG. 5 is a functional block diagram illustrating signal flow in the gasoline injection control device and the gasoline alternative gas fuel injection control device of FIG. 4.

Explanation of symbols on the main parts of the drawings

1: engine 2: injector

10, 11: electronic control unit

I1, ..., In: gasoline injection signal

O1, ..., On: gas fuel injection signal

Japanese Patent Laid-Open No. 6-17709

JP-A-61-138860 Gazette

Japanese Patent Application Laid-Open No. 2004-108148

The present invention relates to a fuel supply method for a gas engine and a gasoline alternative gas fuel injection control apparatus when a conventional gasoline injection system is used for a gasoline alternative gas fuel injection system using gaseous fuel.

It is widely known to use gaseous fuel, such as LPG, whose composition and vaporization characteristics are different from gasoline as fuel for a spark ignition engine. For example, as LPG is used, as described in Japanese Patent Laid-Open No. 6-17709, the LPG is made into a gas state, adjusted to a predetermined pressure, injected into an intake pipe, and supplied to an engine. As described in Japanese Patent Application Laid-Open No. 61-138860, a method of supplying LPG to an intake pipe path in a liquid state and supplying it to an engine is known. On the other hand, since CNG is kept more stable in gaseous state than LPG, it is practically adjusted to a predetermined positive pressure gas and injected into the intake pipe to supply the engine.

When the engine is equipped with an injection system for injecting gas fuel having different characteristics from those of gasoline from the injector to the intake pipe path, the electronic control device for setting the injection amount to give an optimum fuel supply amount according to the engine operating state for the new gas engine You can design and build the system from scratch to control the injector.

However, in the existing engine equipped with the gasoline injection system, since the injection amount which gives an optimal fuel supply amount according to the operation state of an engine is set in the electronic control apparatus which comprises a gasoline injection system, for example, As described in Japanese Patent Laid-Open Publication No. 2004-108148, a gasoline alternative gas fuel having an extremely simple function of calculating a fuel injection amount giving a mixed gas equivalent to this based on the gasoline injection amount by a predetermined calculation using various data. By adding an electronic control device for the fuel and using an injector having an appropriate valve diameter and dynamic range for injection according to the type of fuel, a gasoline alternative gas fuel injection system can be constructed using the existing gasoline injection system. Can be converted to the corresponding engine.

4 is a layout diagram common to a fuel injection system equipped with a conventional fuel supply device including the present invention, and FIG. 5 shows a functional block diagram of a control device installed in the fuel injection system shown in FIG. 4. The system detects the driving state of the engine 1 with each sensor 5 to 9, and outputs the electronic control unit 10 as a gasoline injection control device that outputs gasoline injection signals I1 to In, and a gasoline injection signal. An electronic control unit 11 as a gasoline alternative gas fuel injection control device, which is appropriately corrected for gas fuel and outputs to the injector 2 provided in each cylinder as the gas fuel injection signals O1 to On, is provided.

As shown in the waveform diagram of FIG. 2A, the gasoline injection signal In from the electronic control unit 10 is input to the electronic control unit 11, and the signal is changed from OFF to ON. When the waveform of the gasoline injection start is detected, a predetermined delay time is counted and the gas fuel injection signal On is turned from OFF to ON, and the gas fuel is calculated according to the gasoline injection time X and the engine operating state input from various sensors. According to the injection time Y, the control which injects gas fuel from the injector 2 is performed.

However, as shown in the waveform diagram of Fig. 2B, before the end of the calculated gas injection time Y 'of the gas fuel injection signal On, the gasoline injection signal In is turned ON so that the next injection cycle is performed. In the case of starting, the gas fuel injection signal On may end at the gas injection time Y "and become OFF, and the injection time is shorter than the calculated gas injection time Y ', so that an accurate air-fuel ratio cannot be obtained. There is a problem of deteriorating the operating state of the engine.

The present invention is to solve the above problems, the object is to receive a gasoline injection signal output from the gasoline injection control device to the gasoline injection system already installed in the engine having a gasoline injection control device to In the fuel supply method of the gas engine implemented by the gasoline alternative gas fuel injection control apparatus which calculates injection amount, and the gasoline alternative gas fuel injection system which expanded the injector for gas fuel connected to the said gasoline alternative gas fuel injection control apparatus, When the gasoline alternative gas fuel injection control device executes the injection control of the gas fuel using a flag indicating that the gas fuel is being injected or is not being injected, the flag is set to non-initiated at the time when the start of injection of the gasoline injection signal is detected. Indicating that it is spraying when indicating that it is spraying Initiating the injection of gaseous fuel by setting to a flag, and setting the flag to indicate that it is non-injecting when the flag indicates that it is injecting at the time of detecting the end of the injection of gaseous fuel, and starting to start the injection of the gasoline injection signal. When the flag indicates that the flag is injecting at the time of detection, the flag is set to the flag indicating that it is injecting, and the flag indicating that the flag is injecting when the flag indicates that it is non-injecting at the time of detecting the end of the injection of the gas fuel By setting the gas fuel injection to be started, the gasoline injection system is ensured even when the next injection cycle of the gasoline injection signal is started before the injection of the gas fuel injection signal is started. Regarding the used gasoline alternative gas fuel injection system, Even if the next injection cycle of the gasoline injection signal is started before the end of the injection of the gas fuel calculated in the gas fuel injection signal, it is possible to ensure an accurate injection time of the gas fuel.

Therefore, in the present invention, a gasoline replacement gas fuel injection control device that receives a gasoline injection signal output from the gasoline injection control device and calculates the injection amount of gas fuel to a gasoline injection system already installed in an engine having a gasoline injection control device, And a gas engine fuel supply method implemented by a gasoline alternative gas fuel injection system configured by expanding an injector for gas fuel connected to the gasoline alternative gas fuel injection control device, wherein the gasoline alternative gas fuel injection control device includes a gas fuel. Injection control of the gaseous fuel is executed using a flag indicating that the fuel is being injected or non-injected, and when the flag indicates that the flag is non-injected at the time when the start of injection of the gasoline injection signal is detected, Minutes of gas fuel set by flags The start, and sets a flag showing the injection being in the ratio when the flag at the time of detecting the injection end of the gaseous fuel representing an injection is in progress. On the other hand, when the flag indicates that the flag is being injected at the time when the injection start of the gasoline injection signal is detected, the flag is set to the flag indicating that it is injecting, and when the end of the injection of the gas fuel is detected, the flag is not injected. In the case of indicating that the gas fuel injection signal is being started, the gas fuel injection is started by setting a flag indicating that the fuel is being injected. Secure.

By controlling in this way, even if the next injection cycle of a gasoline injection signal is started before the injection time of the gaseous fuel computed according to the input gasoline injection signal and the detected engine operation state is complete | finished, the injection of the calculated gaseous fuel will be started. Time can be secured, and an appropriate air-fuel ratio can be realized.

In addition, in the fuel supply method of the gas engine, the gasoline alternative gas fuel injection control apparatus uses the gas fuel from the start of the injection of the gasoline injection signal when the next injection cycle of the gasoline injection signal is started after the completion of the injection of the gas fuel. When the gas fuel injection is started with a predetermined delay time until the start of injection of the injection signal, and the next injection cycle of the gasoline injection signal is started before the end of the injection of the gas fuel, a correction in which the delay time is corrected by a predetermined calculation method. When gas fuel injection is started with the delay time, fuel injection control with more suitable injection timing can be realized.

In addition, this correction delay time is easy to ensure the calculated gas fuel injection time, if the time required from the start of the next injection cycle of the gasoline injection signal to the end of the injection of the gas fuel injection signal is subtracted from the delay time.

In addition, the gasoline alternative gas fuel injection system for implementing the above-described fuel supply method for the gas engine, which is installed in the gasoline alternative gas fuel injection system, and a program for executing each step of the fuel supply method described above is stored in the storage means. With the control device, it is possible to reliably and easily realize the fuel supply method for the gas engine described above.

According to the fuel supply method of the gas engine and the gasoline alternative gas fuel injection control apparatus of the present invention, even when the injection cycle of the next gasoline injection signal is started before the end of the injection of the gas fuel calculated in the gas fuel injection signal, the correct gas fuel is started. The injection time of can be secured.

(The best mode for carrying out the invention)

EMBODIMENT OF THE INVENTION Hereinafter, the best embodiment in this invention is described with reference to drawings. 4 is a layout view showing a gasoline alternative gas fuel injection system in which an electronic control unit 11 as a gasoline alternative gas fuel injection control device and an injector 2 for gas fuel are added to a gasoline injection system already installed in an engine. to be. In the present embodiment, a gas fuel to be used is one that is relatively easy to vaporize, such as LPG, and an unshown delivery pipe line extending from a liquid portion of a bomb filled with a gas fuel (not shown) is provided. The injector 2 is connected to the plurality of injectors 2, and the electronic control unit 11 drives and controls each injector 2.

The present invention is applied to a case where an existing gasoline engine equipped with an electronic control unit 10 as a gasoline injection control device and a gasoline injection system equipped with a gasoline injector (not shown) is converted into a gas engine. The electronic control unit 10 according to the engine operating state detected by the throttle opening sensor 8, the MAP sensor 9, the O ² sensor 6, the water temperature sensor 7, and the crank angle sensor 5. The calculated gasoline injection signal is output, the gasoline injector (not shown) is opened and closed by the duty cycle according to this drive signal, the gasoline at the engine flow rate is injected and supplied to the engine, and the ignition stopper 4 is provided at a predetermined timing. As a ignition, this is a well known technique.

In this embodiment, the electronic control unit 11 and the gas fuel injector 2 serving as the gasoline alternative gas fuel injection control apparatus are added to the gasoline injection system to constitute a gasoline alternative gas fuel injection system. In this case, the gasoline injector (not shown) may be removed and replaced with the gaseous fuel injector 2, and the cylinder-specific signal lines from the electronic control unit 10 to the gasoline injector are replaced with the electronic control unit 11 as they are. What is necessary is just to set it as an input signal line.

Here, although it is considered to use the gasoline injector for the injection of gas fuel, the volume flow rate corresponding to the engine required fuel flow rate is much larger than that of gasoline, so in the present invention, a valve capable of appropriate injection of gaseous fuel is possible. A dedicated gas fuel injector 2 having a diameter and a dynamic range was used.

The electronic control unit 11 is a general-purpose electronic control unit having a CPU, a ROM, a RAM, an input / output interface, and the like, which are not shown. The hardware is similar to a conventional gasoline alternative gas fuel control device, but the ROM will be described below. It is characterized by including a program for executing the fuel supply method of the gas engine of the present invention.

As shown in the functional block diagram of FIG. 5, the electronic control unit 11 is output by the electronic control unit 10 as a gasoline injection control apparatus according to the engine operating state, and inputted via the gasoline injection signal line (I1). In accordance with In, a predetermined correction factor is given to calculate an appropriate injection amount of the gas fuel, and the gas fuel injection signals O1 to O2 which give the calculated gas fuel injection amount are injectors (for each cylinder) through the drive signal line ( 2), this function is common to the conventional gasoline alternative gas fuel injection control device.

In addition to this function, the electronic control unit 11 performs gas fuel injection control using a flag indicating that the gas fuel is being injected (1) or non-injecting (2). It is characterized in that the accurate gas fuel injection time can be ensured even when the injection cycle of the next gasoline injection signal is started before the end of the calculated gas injection. That is, a program for executing the steps of the fuel supply method of the gas engine described in detail in the following embodiment is stored in the ROM provided by the storage means of the electronic control unit 11, and the flowchart of FIG. 3 and FIG. The operation of the electronic control unit 11 which performs the fuel supply method of the gas engine in this embodiment is demonstrated in detail using the waveform diagram of 1 below.

Referring to the flowchart of FIG. 3 and the waveform diagram of FIG. 1A, first, a control method in a normal case will be described. The gasoline injection signal from the electronic control unit 10 is input to the electronic control unit 11, and a detection signal is input from each sensor which detects the operation state of an engine. In this input gasoline injection signal In, it is determined whether or not the waveform of the injection start has been detected (A1). If not, the flag is returned to the beginning (return), and if it is detected, the flag indicating the injection state of the gaseous fuel is non- It is determined whether or not the injection is in progress (A2). When the flag indicates that it is injecting, it is set to a flag indicating that it is injecting (B1), and the gas injection is started by starting a delay time for starting the gas injection calculated beforehand (B2).

From the waveform of the gas fuel injection signal, it is determined whether or not the end of gas fuel injection has been detected (A3), and if not detected, returns to the beginning, and if detected, it is determined whether or not the flag indicates that the fuel is being injected (A4). . In this case, since the flag indicates that it is injecting, it is set as a flag indicating that it is injecting (B3) and returns to the beginning.

On the other hand, when the next injection cycle of the gasoline injection signal is started before the end of the calculated injection of the gaseous fuel injection signal, after detecting the injection start of the gasoline injection signal (A1), it is indicated that the flag indicating the injection state is being injected (A2). ). Thus, a flag indicating that non-ejection is being set is set (C1).

At the time when the injection end of the gas fuel injection signal is detected (A3), the flag indicates that it is injecting (A4), and this is set to the flag indicating that it is injecting (C2), and the correction delay which corrected the above-described delay time Start the time and start the injection of the gaseous fuel. The delay time is corrected by subtracting the time required from the start of the next injection cycle of the gasoline injection signal to the end of the gas fuel injection by subtracting from the original delay time. It is easy to realize.

By allowing the electronic control unit 11 to perform each step of the fuel supply method of the gas engine, the waveform diagram of FIG. 1B is obtained from the control in the usual case shown in the waveform diagram of FIG. 1A. Also in the control in the case where the next injection cycle of the gasoline injection signal is started before the end of the calculated injection of the gas fuel injection signal shown in Fig. 9, the injection time Y 'of the gas fuel calculated from the gasoline injection signal In and the engine operating state is ensured. It is possible to realize the air-fuel ratio of the gas fuel accurately.

According to the fuel supply method of the gas engine and the gasoline alternative gas fuel injection control apparatus of the present invention, even when the injection cycle of the next gasoline injection signal is started before the end of the injection of the gas fuel calculated in the gas fuel injection signal, the correct gas fuel is started. The injection time of can be secured.

Claims (4)

In the gasoline injection system installed in the engine having a gasoline injection control device, a gasoline alternative gas fuel injection control device for receiving the gasoline injection signal output by the gasoline injection control device to calculate the injection amount of gas fuel, and the gasoline alternative gas fuel injection In the fuel supply method of the gas engine implemented by the gasoline alternative gas fuel injection system which expanded the gas fuel injector connected to the control apparatus, When the gasoline alternative gas fuel injection control device executes the injection control of the gas fuel using a flag indicating that the gas fuel is being injected or is not being injected, the flag is set to non-initiated at the time when the start of injection of the gasoline injection signal is detected. When the flag indicates that it is injecting, the flag indicating that it is injecting is set to start the injection of gaseous fuel, and when the flag indicates that the flag is injecting when the end of the injection of gaseous fuel is detected, If the flag indicates that the flag is injecting at the time when the injection start of the gasoline injection signal is detected, the flag is set to indicate that the flag is injecting, and when the end of the injection of the gas fuel is detected, the flag is set to non-injection. If it is injecting, set the flag to indicate that it is injecting and The fuel supply method of the gas engine, characterized in that, by to initiate a charge injection, before the gas-injection end of the fuel injection signal is disclosed, even when following the injection cycles of the petrol injection signal, ensure the injection time of the calculated gas fuel. The method of claim 1, The gasoline alternative gas fuel injection control device is configured to perform a predetermined time from the start of injection of the gasoline injection signal to the start of injection of the gas fuel injection signal when the next injection cycle of the gasoline injection signal is started after the completion of the injection of the gas fuel. When the gas fuel injection is started with a delay time and the next injection cycle of the gasoline injection signal is started before the injection of the gas fuel is started, the gas fuel is subjected to correction delay time corrected by a predetermined calculation method. The fuel supply method of the gas engine characterized by starting injection. The method of claim 2, The correction delay time is calculated by subtracting the required time from the start of the next injection cycle of the gasoline injection signal to the end of the injection of the gas fuel injection signal from the delay time. The fuel supply of the gas engine according to any one of claims 1 to 3, which is installed in the gasoline alternative gas fuel injection system and at the same time stores a program for executing each step of the fuel supply method in a storage means. Gasoline alternative gas fuel injection control device for carrying out the method.

Images