KR20060013327A - Apparatus for supplying vaporized gas fuel to engine - Google Patents

Abstract

The present invention provides a gaseous gas fuel supply device for an engine in which heat of engine cooling water and heat of an electric heater are used as heat sources for heating and vaporizing liquefied gas fuel. It is an object of the present invention to assure a low temperature start of the engine by avoiding a malfunction of the electronic control device.

It is assumed that the electronic control device 10 is provided with an energization control means for energizing the electric heater of the sub-heat exchanger 31 when the engine coolant is below the set temperature, which detects the start of the starter motor 42, thereby deciding from the start. It is assumed that the energization of the sub-heat exchanger 31 is stopped for a time of, so that the voltage of the battery 40 does not fall below the minimum operating voltage of the electronic controller 10.

Description

Evaporative gas fuel supply system for engines {APPARATUS FOR SUPPLYING VAPORIZED GAS FUEL TO ENGINE}

1 is a layout view showing an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the electronic control apparatus in the embodiment of FIG. 1.

Fig. 3A is a waveform diagram of each signal and battery voltage in the conventional example, and Fig. 3B is a waveform diagram of each signal and battery voltage in the present embodiment.

(Explanation of symbols for the main parts of the drawing)

One … Fuel tank 3. carburetor

4 … Engine 4b... Intake pipe

5…. Fuel injection valve 10. Electronic controller

13. Relay unit 20.. temperature Senser

30. Pressure regulator 31. Sub-heat exchanger

31a. Heater unit 32... Main heat exchanger

40…. Battery 41. Ignition switch

42. Starter motor 43. Motor driver

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supplying a gas of a predetermined positive pressure vaporized gas obtained by vaporizing liquefied gas fuel to an engine, and in particular, to use heat of engine cooling water as a heating vaporization means of liquefied gas fuel, and to heat an electric heater. The present invention relates to a gaseous gas fuel supply apparatus for an engine that is capable of reliably starting a low temperature.

LPG has been used for fuels of spark ignition engines since ancient times, and liquid LPG as described in Japanese Patent Application Laid-Open No. Hei 6-17709, in addition to the well-known method of adjusting the vaporized gas at atmospheric pressure to suck the intake pipe. It is widely known that the method of adjusting the gas into an intake pipe by adjusting the gas to a predetermined constant pressure vaporized gas. This method has an advantage of not making the injection amount unstable, which is advantageous for practical use, and it is common to use heat of engine cooling water as a means for heating and vaporizing liquid LPG.

However, the heating vaporization means using such engine cooling water has a problem that the liquid LPG is not sufficiently vaporized because the cooling water is cold at the time of cooling. Thus, for example, as described in Japanese Patent Application Laid-Open No. Hei 5-223014 or Japanese Patent Application Laid-open No. Hei 11-324813, in a vaporizer for decompressing and vaporizing LPG, the heat of the engine coolant is used and the gas is released in the LPG path. The means which arrange | positioned an electric heater and made it possible to vaporize LPG by an electric heater even when cooling water is low temperature is proposed.

However, when the liquid LPG is heated and vaporized by an electric heater, the battery power is consumed very much. Therefore, when the starter motor is started, the battery voltage decreases momentarily, which is lower than the minimum operating voltage of the electronic controller for engine control. It is easy to cause problems in engine operation control.

On the other hand, when the ignition switch employed in the gasoline fuel system is set to the starter motor drive position, a sequence method of applying power to the vaporized gas fuel system by turning off the power of other accessories in the vehicle and suppressing power consumption is applied. When the heater is turned off during the starter motor rotation, the liquid LPG is sent out to the fuel injection valve without vaporizing, which makes it difficult to start the engine.

[Patent Document 1] Japanese Unexamined Patent Publication No. Hei 6-17709

[Patent Document 2] Japanese Patent Application Laid-Open No. 5-223014

[Patent Document 3] Japanese Patent Application Laid-Open No. 11-324813

The present invention is to solve the above problems, and the electric heater is used for the vaporized gas fuel supply apparatus of the engine by using the heat of the engine cooling water for the heat vaporization of the liquefied gas fuel and the heat of the electric heater. The biggest problem is that the battery voltage is not excessively lowered at the time of low temperature start-up to be used, which reliably avoids the occurrence of malfunction of the electronic control device and makes sure the low temperature start-up is assured.

Accordingly, the present invention provides a vaporizer using an engine coolant and an electric heater as a heat source for heating and vaporizing liquefied gas fuel stored in a fuel tank, and vaporizing gas adjusted to a predetermined constant pressure by a vaporizer to an intake pipe of an engine. With respect to the gaseous gas fuel supply device of an engine having a fuel injection valve and an electronic control device having an electric control device of the electric heater, the electric supply control device energizes the electric heater when the engine coolant is below the set temperature, and starts the starter motor. It is assumed that the energization of the electric heater is stopped from the start for a predetermined time by detecting the start of the.

In this way, the electronic control device having the energization control means programmed with a simple logic is made to stop the energization of the electric heater in accordance with a period in which the battery voltage is lowered most from the starter motor startup at the low temperature start of the engine. Since the lowest operating voltage of the control device can be ensured, the low temperature start of the engine can be ensured by avoiding the operation failure.

In addition, when the energization stop time to the electric heater is 0.5 seconds to 2 seconds, while sufficiently covering the time that the battery voltage is greatly reduced by the power consumption of the starter motor, the energization stop time of the electric heater is minimized, The minimum operating voltage of the electronic controller can be securely ensured, and the liquefied gas fuel can be avoided from being sent to the fuel injection valve as a liquid.

Further, when the energization stop time to the electric heater by the energization control means is changed in accordance with the engine coolant temperature, the energization stop time at any temperature corresponds to the length of time when the battery voltage which changes according to the environment temperature greatly decreases. Can be assured.

Further, in the gaseous gas fuel supply device for the LPG engine, when the ignition switch is on, the output signal from the engine coolant temperature sensor is detected, and when the engine coolant temperature does not reach a predetermined temperature, it is assumed that the electric heater is energized. Since the electronic controller can judge whether or not the electric heater is energized in a relatively simple order, this can be performed in a very short time without excessive processing burden.

Referring to the drawings, an embodiment of the present invention will be described. In FIG. 1 which shows a layout view of an engine provided with a vaporization gas fuel supply device of the present embodiment, LPG is stored in the fuel tank 1, and the fuel tank ( A fuel supply line 9A provided with an electromagnetically driven shutoff valve 2 extending from 1) is connected to a vaporizer 3 equipped with a main heat exchanger 32 using engine coolant as a heat source.

The vaporizer | carburetor 3 vaporizes liquefied gas fuel and adjusts it to the vaporization gas of predetermined | prescribed static pressure, The downstream side of the main heat exchanger 32 is provided with the subheat exchanger 31 which used the electric heater as a heat source, and the downstream side The pressure regulator 30 is disposed. The fuel supply line 9B extending from the vaporizer 3 is connected to the fuel injection valve 5 provided in the intake line 4b of the engine 4.

The main heat exchanger 32 which uses the vaporizer | carburetor 3 and the engine coolant attached to it as a heat source is the same as the well-known well-known generally, The coolant jacket 4a and the main heat exchanger 32 which were provided in the engine 4 Cooled water circulated through the cooling water passages 8a and 8b, and the vaporized gas generated by heating the liquefied gas fuel by the heat of the cooling water is adjusted to a constant pressure at a predetermined pressure in the pressure regulator 30 to supply the supply pipe. It is sent to 9B.

In addition, the sub-heat exchanger 31 provided between the main heat exchanger 32 and the pressure regulator 30 overlaps the PTC heater, which is an electric heater (not shown), with the heat transfer plates in close contact with each other, and overlaps the peripheral edges with the circumferential wall. The heater unit 30a, which is in a gas-liquid state by being enclosed, is accommodated and mounted in a housing having an inlet and an outlet of the LPG so as to have a space on its entire circumference, and the heat exchange is performed by performing heat exchange while the LPG passes through this space. It is supposed to be. In addition, the heat transfer plate of the heater unit 30a also serves as an electrode, and is connected to the battery 40 side through the relay unit 13, and the relay unit 13 is connected to the electronic controller 10 to control the energization thereof. It is supposed to be. In addition, when a plurality of heater units 30a are arranged in parallel and a fuel flow path therebetween, the heat exchange rate can be further improved.

The electronic control apparatus 10 has a predetermined control program installed therein, and has a normal fuel injection control function and an energization control means for controlling energization to the sub-heat exchanger 31. That is, whether or not heat vaporization of the liquid LPG is impossible or insufficient by the main heat exchanger 32 based on the engine coolant temperature detected by the temperature sensor 20 disposed in the coolant jacket 4a of the engine 4 in sequence. When it is judged whether or not it is determined to be impossible or insufficient, the relay unit 13 issues a command to energize the sub-heat exchanger 31.

The energization control means stops the energization to the sub-heat exchanger 31 when the engine coolant temperature rises and determines that vaporized gas of the engine maximum required fuel flow rate can be generated only by heating vaporization by the main heat exchanger 32. It is supposed to be. In addition, this determination is performed simultaneously with turning on the ignition switch 41, and is made to perform an energization command immediately when it is determined that electricity supply is needed for the sub-heat exchanger 31. FIG. Therefore, LPG can be avoided from being sent to the fuel injection valve 5 as it is liquid at low temperature startup of the engine.

In addition, the electronic control apparatus 10 is connected to the motor driver 43 which drives the starter motor 42, and when the starter motor 42 is started while energizing the sub-heat exchanger 31, an electricity supply control means. Is programmed to stop the energization of the sub-heat exchanger 31 between 0.5 seconds and 2 seconds from the start of the operation.

By such a configuration, the energization of the PTC heater can be temporarily stopped at a time when the power consumption of the starter motor 42 at the time of low temperature start-up is large, and the voltage of the battery 40 is controlled by the electronic controller 10. It can be avoided to lower until it causes malfunction. In addition, the energization stop time to the sub-heat exchanger 31 is variable between 0.5 second and 2 seconds according to the engine coolant temperature detected at the start of the engine, and is set to 2 seconds at cryogenic temperatures such as minus 30 degrees or less. If it is controlled to be 1 second at minus 10 degrees or less and 0.5 seconds at 0 degrees or more, the low temperature start of the engine can be ensured.

Hereinafter, the operation of the vaporization gas fuel supply device of the present embodiment will be described using the flowchart shown in FIG. 2.                     

At the start of the engine 4, when the ignition switch 41 is turned on, the electronic control apparatus 10 detects the engine coolant temperature using the temperature sensor 20 (A1). Further, it is judged by the energization control means whether or not this temperature reaches the set temperature (A2). If the set temperature is not reached, it is determined that the vaporization of the LPG is impossible or insufficient cooling water temperature (B1), and the relay unit 13 is commanded to energize the sub-heat exchanger 31 (B2). On the other hand, when it is determined that the set temperature has been reached and that the temperature is sufficient to vaporize the LPG (A3), the energization command to the sub-heat exchanger 31 is not issued (A4).

During the energization of the sub-heat exchanger 31, the starter motor drive signal is outputted by setting the ignition switch 41 to the starter position, and the starter motor 42 is started via the motor driver 43 (B3), When the electronic control apparatus 10 detects this (B3), the electricity supply control part stops electricity supply to the sub heat exchanger 31 by the electricity supply control means (B4). Then, a predetermined time is counted from the stop of energization (B5), and the energization to the sub-heat exchanger 31 is resumed (B6).

By doing in this way, the electricity supply to the sub-heat exchanger 31 can be stopped by the period with the largest power consumption during the starter motor 42 driving, and the voltage of the battery 40 falls and the electronic control apparatus 10 The problem which arises by temporarily lowering the minimum operating voltage of) can be avoided.

Further, the electronic control apparatus 10 continuously detects the engine coolant temperature even when the sub-heat exchanger 31 is energized, and determines that the coolant temperature is a temperature sufficient for vaporizing the LPG by the energization control means. Is done. This starts heating vaporization of LPG by only the sub-heat exchanger 31 or this and the main heat exchanger 32 at low temperature startup, and then heating vaporization by the two heat exchangers 31 and 32. Finally, heat vaporization by only the original main heat exchanger 32 is performed.

Next, an example of the waveform diagram in the voltage of the various signals and the voltage of the battery 40 from when the ignition switch 41 is turned on in the present embodiment until the engine 4 starts and the rotation speed is stabilized is shown. The explanation is further added using FIG. 3 (B), comparing with the waveform diagram of the conventional example shown in FIG. 3 (A).

Referring to Fig. 3A, when the ignition switch is turned to the ON position in the conventional vaporized gas fuel supply device, the electric heater energization signal is output at the same time, and the battery voltage decreases by approximately 3 V by the energization. When the ignition switch is turned to the starter motor drive position, the starter motor drive signal is output, whereby the battery voltage is further lowered, which is less than 6V for a moment. Therefore, the operation control of the engine becomes inoperable below the minimum operating voltage of the electronic control device, and it becomes difficult to keep the engine operating state at the start-up satisfactorily.

On the other hand, when the ignition switch 41 is set to the starter motor 32 drive position in the present embodiment, the electric heater energization signal is turned off for a predetermined time. As a result, the timing at which this is turned off and the timing at which the battery voltage of the conventional example greatly decreases coincide with each other. Thus, in the conventional example, the maximum dropping range of the voltage is 5 even when the battery voltage decreases at least 9V. It is suppressed at about -6V, and it does not go below the minimum operating voltage of the electronic control apparatus 10 even one instant. Accordingly, while the heat exchange of the LPG by the sub-heat exchanger 31 is sufficiently secured at the start of the engine 4 at low temperature, the operation of the electronic control apparatus 10 is not caused, and the operation of the LPG at start-up The operating state of the engine 4 can be maintained satisfactorily.

As described above, according to the vaporization gas fuel supply apparatus according to the present embodiment, the energization stop time to the PTC heater is set in accordance with the timing at which the power consumption of the starter motor peaks during low temperature start using the electric heater. By doing so, the battery voltage is not excessively reduced, and therefore, the malfunction of the electronic control apparatus can be reliably avoided, so that the low-temperature starting of the engine can be ensured.

According to the present invention, it is possible to reliably avoid the malfunction of the electronic control device by not excessively lowering the battery voltage at the low temperature of the engine using the electric heater, and to ensure the low temperature of the engine. will be.

Claims (4)

A vaporizer using an engine coolant and an electric heater as a heat source for heating and vaporizing liquefied gas fuel stored in a fuel tank, a fuel injection valve for injecting vaporized gas adjusted to a predetermined static pressure by the vaporizer to an intake pipe of an engine; A gaseous gas fuel supply apparatus for an engine having an electronic control apparatus having an electricity supply control means for the electric heater, The energization control means energizes the electric heater when the engine coolant is below the set temperature, but stops the energization to the electric heater from the start for a predetermined time by detecting the start of the starter motor. Gas fuel supply. 2. The vaporization gas fuel supply apparatus for an engine according to claim 1, wherein the energization stop time to the electric heater is 0.5 seconds to 2 seconds. The gas supply gas fuel supply apparatus for an engine according to claim 2, wherein the energization stop time to the electric heater by the energization control means is variable in accordance with the engine coolant temperature. 4. The power supply control means according to any one of claims 1 to 3, wherein the energization control means detects an output signal from the engine coolant temperature sensor when the ignition switch is on, and when the engine coolant temperature does not reach the set temperature. A gaseous gas fuel supply apparatus for an engine, characterized in that the energization of the electric heater is started.

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