JPS6120708B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel vaporization promoting device for, for example, an automobile engine.

Conventionally known vaporization accelerators of this type heat the riser wall by exposing the outer surface of the riser wall below the carburetor in the intake pipe connected between the carburetor and the engine to engine cooling water or engine exhaust gas. It has been proposed to accelerate the vaporization of liquid fuel (gasoline) that has dripped onto the inner surface of the riser wall without being completely vaporized.

However, when exhaust gas is used, the riser wall overheats, so only a small portion of the exhaust gas is used, and as a result, sufficient heat cannot be obtained to promote vaporization, especially when the fuel is needed during cold starting. Insufficient vaporization. Furthermore, when cooling water is used, the temperature of the cooling water is low immediately after a cold start, and therefore it is not possible to promote vaporization of the fuel.

As described above, conventionally known methods cannot promote the vaporization of fuel during a cold start when fuel vaporization is especially necessary, and as a result, the fuel is drawn into the engine in a liquid state, resulting in poor warm-up of the engine and engine failure. may cause a misfire.

Therefore, in view of the above points, the present invention includes an intake pipe connected between the fuel supply device and the engine,
The outer surface of the riser wall of the intake pipe below the fuel supply device is brought into contact with the cooling water of the engine or the exhaust gas of the engine, thereby promoting vaporization of the liquid fuel adhering to the inner surface of the riser wall. In a fuel vaporization accelerator for an engine, the riser wall is disposed below the fuel supply device at a position that does not obstruct the flow of intake air to the engine on the inner surface of the riser wall, and has a positive resistance temperature characteristic and a Kiuri point at a specific temperature. a plate-shaped ceramic heater that generates heat when energized; an electrode that is disposed on a surface of the heater on the fuel supply device side and has an opening that exposes the heater so that liquid fuel from the fuel supply device side adheres; an actuator for rotating the heater to a predetermined position that does not obstruct the flow of intake air from the inner surface of the riser wall to the engine; and a control means for controlling the operation of the actuator in accordance with a warm-up state of the engine. The actuator is configured to rotate the heater from the inner surface of the riser wall to the predetermined position via the control means at the end of warm-up operation of the engine. By using this device, the ventilation resistance of the intake air due to the plate-shaped ceramic heater is minimized, and during warm-up operation immediately after a cold start, the ceramic heater can promote the vaporization of fuel, and as a result, the engine It is possible to prevent malfunctions in the warm-up operation of the engine, leading to misfires, and the ceramic heater is rotated after the warm-up operation is completed to prevent heat from the engine cooling water or engine exhaust gas from being taken away by the ceramic heater. It is an object of the present invention to provide a fuel vaporization promoting device that can promote the vaporization of fuel using the heat, and can therefore promote vaporization of the fuel both before and after warming up the engine.

The present invention will be specifically explained below with reference to embodiments shown in the drawings. In Fig. 1, 1 is a carburetor, 2 is an intake pipe connecting the carburetor 1 and the engine 3, and 4 is a plate-shaped ceramic heater made of, for example, barium titanate, which has a positive resistance as shown in Fig. 6. It has temperature characteristics and a Curie point at a specific temperature, and generates heat when energized. The screen of this heater 4 is formed with a thin film, for example, a nickel electrode (not shown). The heater 4 is connected to the carburetor 1 of the intake pipe 2.
The heater 4 is placed in a recess 5a of the riser wall 5 located below the riser wall 5.
It is rotatable so that it can move in and out of the recess 6a of the side wall 6 of the intake pipe 3. Reference numeral 7 denotes a cooling water passage portion that guides a portion of the cooling water of the engine 3 to the outer periphery of the riser wall 5, and is connected to a radiator (not shown).

Next, the specific structure of the heater 4 and the rotating structure of the heater 4 will be explained with reference to FIGS. 2 to 4. A positive electrode plate 8 is attached to the upper surface of the heater 4 around its periphery, and a negative electrode plate 9 is attached to the entire lower surface thereof. In other words, heater 4
The surface of the carburetor 1 side is exposed through the opening of the front electrode plate 8 so that the liquid fuel from the carburetor 1 side is attached to the surface of the heater 4. Both electrode plates 8 and 9 have metal bolts 10, metal spring washers 11,
It is fixed to the heater 4 via an electrically insulating bush 12 and a metal nut 13 so as not to fall off. 1
Reference numeral 4 denotes a metal plate spring, and this plate spring 14 is fixed by tightening a metal nut 17 to a metal bolt 16 inserted into a hole 5ab of the riser wall 5 via an electrically insulating bush 15. This leaf spring 14 and bolt 10
and configure the switch. Note that 18 is a lead wire connected to a battery of an on-vehicle power source, and a terminal 18a thereof is fixed between a nut 17 and a metal washer 19. As a result, the positive electrode plate 8 of the heater 4 includes the bolts 10, leaf springs 14, bolts 16,
It is electrically connected to the positive terminal of the battery via the lead wire 18.

Reference numeral 20 denotes a metal shaft, which is formed by winding the end of the negative electrode plate 9 of the heater 4.
It is fixed at Reference numeral 21 denotes a metal bearing, which is attached to the metal bolt 21 of the riser wall 5 of the intake pipe 2 so as to surround the shaft 20 holding portion of the negative electrode plate 9.
It is fixed at a. Note that since the negative terminal of the battery is generally grounded to the engine 3, the negative electrode plate 9 of the heater 4 is electrically connected to the negative terminal of the battery via the engine 3, the intake pipe 2, and the bearing 21. are doing.

The end of the shaft 20 is fixed to a lever 23 of a diaphragm type negative pressure actuator 22. Note that this actuator 22 is connected to the shaft 2
2a, a diaphragm 22b, a case 22c, a spring 22d, and a negative pressure inlet 22e. Note that when the heater 4 rotates, the leaf spring 14 extends to the solid line position as shown in FIG.
When the bolt 10 of the positive electrode plate 8 comes into contact with the leaf spring 14, the leaf spring 14 is bent as shown by the dashed line.

Next, the control means for controlling the operation of the actuator 22 will be explained with reference to FIG. 24 is an electromagnetic three-way valve, and a thermistor type cooling water temperature sensor 2
When the coolant temperature detected in step 5 is above a predetermined value, the current is applied via the amplifier 26, and when the coolant temperature is below the predetermined value, the current is cut off via the amplifier 26. When the electromagnetic valve 24 is de-energized, it operates to introduce negative pressure from a negative pressure source 27, such as a brake booster, into the negative pressure chamber 22f of the actuator 22, and when it is conductive, it operates to introduce the negative pressure from the negative pressure chamber 22f of the actuator 22. It operates to cut off the communication between 22f and the negative pressure source 27 and introduce the atmosphere into the negative pressure chamber 22f. Note that this solenoid valve 24 has a pipe 24 connected to the negative pressure chamber 22f of the actuator 22.
a, a pipe 24b open to the atmosphere, and a pipe 24c connected to a negative pressure source 27.
28 is a battery.

Next, the operation of the above configuration will be explained. Immediately after the cold start of the engine 3, the engine cooling water temperature is extremely low, so the electromagnetic valve 24 is not energized, and atmospheric pressure is introduced into the negative pressure chamber 22f of the actuator 22. Therefore, the shaft 2 of the actuator 22
2a does not move, and the heater 4 is located at the solid line position in FIGS. The plate spring 14, the positive electrode plate 8, and the electrically connected metal bolt 10 are in contact with each other and are set in an electrically conductive state, so that each electrode 8 of the heater 4 9 is energized and the heater 4 generates heat. At this time, since the temperature of the heater 4 itself is low, the resistance value is small and a large current flows through it, resulting in a high temperature in a very short time. Immediately after such a cold start, the fuel is poorly atomized in the vaporizer 1, and this fuel collides with the throttle valve 1a, becomes droplets, and drips onto the surface of the heater 4.
This dripped liquid fuel is well vaporized by the heat of the heater 4, so compared to when it is sucked into the engine 3 in a liquid state, it does not cause shortness of breath immediately after starting, and warm-up operation after starting is possible. It is in good condition and will not misfire. When the temperature of the heater 4 becomes high and reaches the Curie point, the resistance value increases and only a small amount of current flows, so the temperature decreases.When the temperature decreases, the resistance value decreases and a large current flows, and the temperature decreases again. Temperature rises. Since this is repeated, even if the heater 4 continues to be energized due to a failure, the heater 4 will not overheat.

By the way, when the warm-up operation of the engine 3 is completed and the temperature of the engine cooling water temperature sensor 25 reaches a predetermined value or more, the electromagnetic valve 24 is energized and the negative pressure of the negative pressure source 27 is introduced into the negative pressure chamber 22f of the actuator 22. Therefore, the diaphragm 22 of the actuator 22
b is displaced against the spring 22d and pulls the shaft 22a and the lever 23, so that the heater 4 is moved via the bearing 21 to the position indicated by the dashed line in FIGS. 1 and 5, that is, relative to the riser wall 5 of the intake pipe 2. It is rotated to a position where it faces the inner surface of the side wall 6 in the recess 6a of the side wall 6 of the intake pipe 2, which is set vertically, with a slight gap therebetween. At the same time, the leaf spring 14 separates from the bolt 10, so that the power to the heater 4 is cut off. After the warm-up operation is completed, the cooling water passage section 7
The riser wall 5 is heated by the engine cooling water passing through the riser wall 5, and the fuel dripping onto the inner surface of the riser wall 5 is vaporized by the heat of the engine cooling water. At this time, since the heater 4 is rotated and is not located on the riser wall 5, the heat of the engine cooling water is not taken away by the heater 4, and this heat can be effectively used for vaporizing the fuel. Note that by promoting vaporization of the fuel even after the warm-up operation is completed, suffocation during acceleration is prevented and smooth acceleration is achieved.

Figure 7 shows the temperature changes at points A, B, and C in Figure 1. When the power to the heater 4 is cut off at time t ₁ when warm-up is completed, the temperature at point A of the heater 4 at time t ₂ . It can be seen that this is lower than points B and C. This indicates that the heat of the engine cooling water is being taken away by the heater 4, and it is better to eliminate the heater 4 after warm-up is completed to promote vaporization of the fuel. Therefore, as described above, the structure in which the heater 4 is rotated after warm-up is completed so that the heat of the engine coolant is not taken away by the heater 4 is extremely effective in promoting vaporization of the fuel after warm-up is completed. I know what you're doing.

FIG. 8 shows another embodiment of the present invention in which the rotating shaft 29a of the motor 29 is fixed to the negative electrode plate 9 of the heater 4, and the heater 4 is rotated by the motor 29.

The present invention is not limited to the above embodiments, but can be modified in various ways as described below.

(1) It is not necessary to provide recesses 5a and 6a in the riser wall 5 and side wall 6 of the intake pipe 2, respectively.In other words, the inner surfaces of the riser wall 5 and side wall 6 are not required to prevent the heater 4 from obstructing the flow of intake air to the engine 3. It should be set according to the following.

(2) In addition to the carburetor 1, there is a fuel injection valve as a fuel supply device.

(3) The cooling water temperature sensor 25 is not limited to the thermistor type, but may also be a bimetal type, thermoferrite type, or the like.

(4) Instead of detecting the cooling water temperature, the warm-up state of the engine 3 may of course be detected by detecting the lubricating oil temperature of the engine 3 or the cylinder block temperature of the engine 3.

(5) It is also possible to integrally configure the cooling water temperature sensor and the atmospheric negative pressure switching valve.

(6) A timer device can also be used as a control means for the actuators 22 and 29 so that the warm-up operation ends after a predetermined period of time after the engine is started.

(7) A portion of the exhaust gas from the engine 3 may be used to heat the riser wall 5 of the intake pipe 2.

(8) The surface of the heater 4 may be made uneven in order to increase the heat dissipation area.

(9) Various switch structures can be selected other than the above embodiments.

As detailed above, according to the present invention, there is provided an intake pipe connected between a fuel supply device and an engine, and the outer surface of the riser wall of the intake pipe below the fuel supply device is used for cooling the engine. In the fuel vaporization promoting device for an engine, which promotes vaporization of the liquid fuel adhering to the inner surface of the riser wall by contacting with water or the exhaust gas of the engine, the inner surface of the riser wall below the fuel supply device is provided. a plate-shaped ceramic heater that is disposed in a position that does not obstruct the flow of intake air to the engine, has positive resistance temperature characteristics and a Kyuri point at a specific temperature, and generates heat when energized; and a surface of the heater on the fuel supply device side. an electrode having an opening that exposes the heater so that liquid fuel from the fuel supply device adheres thereto; and an electrode located at a predetermined position that does not obstruct the flow of intake air from the inner surface of the riser wall to the engine. and a control means for controlling the operation of the actuator according to the warm-up operation state of the engine, and when the warm-up operation of the engine is finished, the heater is turned on via the control means. Since the engine fuel vaporization accelerator is configured to be rotated by the actuator from the inner surface of the riser wall to the predetermined position, it is possible to avoid sufficient atomization during a cold start that requires warm-up. The liquid fuel drips onto the exposed surface of the heater, is directly heated from the heater surface, and vaporizes well. Therefore, the liquid fuel is sucked into the engine without causing breathing problems. This has the effect of smooth warm-up without the need for warm-up, and after the warm-up of the engine is completed, the power to the heater is cut off and the actuator rotates the heater to move it away from the inner surface of the riser wall. Because of this, the heat from the engine cooling water and engine exhaust gas is not absorbed by the heater and acts on the riser wall, and this heat can be effectively used to promote the vaporization of liquid fuel after warm-up, and therefore the warm-up is completed. As a result of promoting the vaporization of the fuel even after acceleration, the heater has the effect of preventing breathing during acceleration.In addition, the heater has a positive resistance-temperature characteristic and has a Curie point at a specific temperature. This Curie point can be set to a temperature suitable for vaporizing the liquid fuel that has dripped and adhered to it, and in addition, the heater can be exposed to ensure that the fuel at this temperature is transferred directly to the heater. The heater is placed on the inner surface of the riser wall during warm-up operation, and is rotated to the specified position after warm-up operation is completed. However, in either case, they are placed in a position that does not obstruct the flow of intake air to the engine, so there is almost no ventilation resistance due to the data in the intake pipe.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the device of the present invention, and FIG. 1 is a sectional view showing the arrangement position of the ceramic heater 4 with respect to the riser wall 5 of the intake pipe 2;
2 is a sectional view showing the mounting structure of the electrodes 8 and 9 of the ceramic heater 4, and FIG. 3 is a sectional view of the ceramic heater 4.
4 is a perspective view showing the attachment relationship between the actuator 22 that rotates the ceramic heater 4, and FIG. 2 is a sectional view showing the operation control means 24 and 25 of the rotating actuator 22 of the ceramic heater 4 along with other components, and also includes an electric circuit. FIG. 6 is a characteristic diagram showing an example of the characteristics of the ceramic heater 4, and FIG.
The figure is a characteristic diagram for explaining the effects of the present invention, and Figure 8 is an actuator 2 in another embodiment of the present invention.
9 is a perspective view showing FIG. 1... Carburetor, 2... Intake pipe, 3... Engine, 4... Ceramic heater, 5... Riser pipe,
7... Cooling water passage section, 10, 14... Bolts and plate springs forming switches, 22, 29... Actuators, 24, 25... Solenoid valves forming control means, cooling water temperature sensors.

Claims (1)

[Scope of Claims] 1. An intake pipe connected between a fuel supply device and an engine, and an outer surface of a riser wall of the intake pipe below the fuel supply device is connected to the cooling water of the engine or the engine. In the fuel vaporization promoting device for an engine, the fuel vaporization promoting device for an engine is configured to promote the vaporization of the liquid fuel adhering to the inner surface of the riser wall by bringing the inner surface of the riser wall below the fuel supply device into contact with the engine. a plate-shaped ceramic heater that is placed in a position that does not obstruct the flow of intake air, has a positive resistance-temperature characteristic and a Curie point at a specific temperature, and generates heat when energized; , an electrode having an opening that exposes the heater so that liquid fuel from the fuel supply device adheres thereto; and a movable electrode that moves the heater to a predetermined position that does not obstruct the flow of intake air from the inner surface of the riser wall to the engine. and a control means for controlling the operation of the actuator according to a warm-up operation state of the engine, and when the warm-up operation of the engine is completed, the heater is controlled to be connected to the inner surface of the riser wall via the control means. A fuel vaporization promoting device for an engine, characterized in that the device is configured to be rotated from the actuator to the predetermined position by the actuator. 2. The predetermined position at which the heater is rotated by the actuator that does not obstruct the flow of intake air to the engine is slightly away from the inner surface of the side wall of the intake pipe that is perpendicular to the riser wall of the intake pipe. The fuel evaporation promoting device for an engine according to claim 1, wherein the fuel vaporization promoting device for an engine is located at a position where they face each other with a gap between them. 3. In the fuel vaporization promoting device for an engine according to claim 1 or 2, there is provided a switch that cuts off electricity to the heater when the heater is rotated from the inner surface of the riser wall to the predetermined position. What is claimed is: 1. A fuel vaporization accelerator for an engine, characterized in that: