JPS5933888Y2 - Internal combustion engine intake air heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric intake air heating device for an internal combustion engine, and more specifically to a control circuit for energization thereof.

BACKGROUND ART Various heat risers for heating intake air of internal combustion engines using electric heating elements have been proposed in the past.

Among these, those using PTC ceramic as a heating element are extremely useful for their ability to quickly rise in temperature.

This is due to the fact that the electrical resistance of the PTC ceramic is extremely small at room temperature, and it consumes a large amount of power for a while after the start of energization.

Generally, it is easy to energize this PTC ceramic at the same time as the ignition switch is closed.
There are two problems with this type of device:

- Since a considerable amount of power is supplied to the PTC ceramic during cranking by the starter, sufficient power cannot be supplied to the starter, making it difficult to start the internal combustion engine.

This is particularly dangerous when the battery is deteriorated.

■ Since it is difficult to start an internal combustion engine, when cranking is performed several times, the ignition switch is often left closed during that time, and there is a risk that the battery will die at such times.

Therefore, when the internal combustion engine is stopped or rotating at a low speed such as during cranking, it is wise to stop energizing the PTC ceramic.

The present invention was developed in consideration of this point, and detects the rotational speed of the internal combustion engine, and when the internal combustion engine has not reached a state of complete explosion, it will activate the PTC circuit even if the ignition switch is closed. The purpose of this is to facilitate cranking of the internal combustion engine and reduce the risk of the battery dying by stopping power to the electric heating element.

The present invention will be described below with reference to embodiments shown in the drawings.

Figure 1 shows the intake pipe section of an automobile internal combustion engine.
is an electric heat riser, casing 2, PTC
It is composed of a ceramic holder 3, an upper spring holder 4, a lower spring holder 5, a coil spring 6, and a stay 7.

The casing 2 is made of aluminum and includes a cylindrical portion 8 and
It consists of a flange part 9 which is the hem of the cylinder and a heat riser part 10 which is the lid of the cylinder.

Reference numeral 11 denotes an intake pipe of the internal combustion engine, and the part of the intake pipe 11 directly below the throttle valve 12, which is generally called the heat riser part, is hollowed out in a circular shape, and the casing 2 is inserted into the circular hole 13. The flange portion 9 is fixed to the intake pipe wall by a bolt 9.

An O-ring 14 is provided on the cylindrical portion 8 of the casing 20 to provide a gas seal between the inside of the intake pipe 11 and the outside air.

The outer surface of the heat riser section 10 of the casing 2 is located at a position where it constitutes a part of the intake pipe wall, and is designed so as not to form a significant level difference with the intake pipe wall.

PTC ceramic 3 is a conductive adhesive on the inner surface of the heat riser section 10.

For example, it is bonded with an adhesive made of epoxy resin mixed with silver powder.

The PTC ceramic 3 is sintered with barium titanate as its main component, and the Curie point at which the resistance value rapidly increases is, for example, 120°C.

Further, the shape of the PTC cell □tsuku 3 is a thin disk shape, which is one size smaller than the inner diameter of the cylinder 8.

The PTC cell □ 3 is pressed against the heat riser 10 by a spring 6, and this spring 6 is provided with spring holders 4.5 at both ends, and the PTC cell □
The holder 4 in contact with the hook 3 also serves as a positive electrode.

A claw 14 extends outward through the stay 7 on the holder 5 in contact with the stay 7, and this serves as a terminal for the positive electrode.

The spring 6 is made of phosphor bronze, for example. Holder 4, 5
are made of copper plates, and both of these are PTC
It also serves to form a current supply circuit to the ceramic 3.

The stay 7 is a thin disk made of non-conductive resin,
It is supported by the cylindrical portion 8 of the casing 2 by a circlip 15.

A water jacket 16 is formed in the intake pipe 11, through which water 17 is introduced after cooling the internal combustion engine.

A water temperature switch 18 that operates by sensing the temperature of this water 17
is provided on the intake pipe wall.

As the water temperature switch 18, a known bimetal type switch, a combination of thermoferrite, a magnet, and a reed switch may be used.

Two terminals 19 and 20 protrude from the water temperature switch 18, and when the water temperature exceeds 60°C, this terminal 19
When the water temperature is below 60℃, the continuity between terminal 1 and 20 is broken.
There is continuity between 9 and 20.

The terminal 19 is connected to the pawl 14.

The terminal 20 is connected to the positive electrode of a battery 23 via an engine rotation switch 21 and an ignition switch 22.

The engine rotation switch 21 operates in response to the rotation speed of the internal combustion engine, and for example, opens when the engine speed is 400 rpm or less;
It closes when the temperature exceeds pm.

Such switches and switch circuits are known;
For example, there are known switches that use a centrifugal governor, or switch circuits that close a relay via a transistor when a signal exceeding 400 rpm is obtained by counting ignition pulse signals from an internal combustion engine. Can be done.

The negative electrode of the battery 23 is connected to the intake pipe 11 or the intake pipe 1.
1 and other parts having the same potential, such as the housing of an internal combustion engine, and are grounded.

Next, the operation of the device of the present invention with the above configuration will be explained.

Ignition switch 22 for starting the internal combustion engine
When the PTC ceramic 3 is closed, the temperature of the water 17 is the outside temperature (around 20 degrees Celsius), and the water temperature switch 18 is also closed, but the engine rotation switch 21 is open, so the PTC ceramic 3 No power is supplied.

When cranking is performed using the battery 23 by turning a starter (not shown), the cranking rotational speed is normally about 100 to 300 rpm, so the engine rotation switch 21 remains open, and the PTC ceramic 3 is not energized.

Therefore, the electric power of the battery 23 is effectively used for the starter, and the starter can easily start the internal combustion engine.

Normally, after 2 to 3 seconds of cranking, the internal combustion engine will completely explode and start rotating on its own.

The rotation at this time is first idle, and it is normal SO.
Since the engine speed is about 0 to 1600 rpm, the engine rotation switch 21 is closed.

Therefore, at this time, the switches 18, 2L and 22 are all closed, so that the PTC cell switch 3 starts to be energized.

The current comes out from the positive terminal of the battery 23, and is passed through the ignition switch 22, engine rotation switch 21. Water temperature switch 18
It reaches the terminal 14 of the lower spring holder 5, passes through the spring 6, the upper spring holder 4, and the PTC ceramic 3.

When passing through this PTC ceramic 3, power is consumed and heat is generated.

After passing through the PTC ceramic 3, the air passes through the casing 2, reaches the intake pipe 11, and returns to the negative electrode of the battery 23.

The PTC ceramic 3 has a resistance at room temperature of about 0.3Ω, and by applying a voltage of 12V from the battery 23, it can generate 4OA.
current is allowed.

The power consumption at this time is 480W, and since all of this generates heat, the PTC ceramic 3 generates 1 power in 1 to 2 seconds.
Reach 20'C.

At this time, the heat riser part 10 is heated to 80 to 1000 in 2 to 3 seconds.
G, and quickly performs the actions of fuel atomization and intake air heating.

When the temperature reaches 120° C., the resistance of the PTC ceramic 3 becomes about 2Ω, and the power consumption decreases to 72W, and the temperature does not rise above that.

When fast idle is performed for several tens of seconds, or after a few seconds have passed after starting normal operation, the rotational speed under no load, that is, the idle rotational speed, is normally 500 to 800 rpm, but the engine rotation switch 21 is still activated. It remains closed, and the PTC ceramic 3 continues to be energized.

After 1 to 3 minutes have passed after the complete explosion, the temperature of the cooling water 17 will be 60℃.
Normally, the water temperature switch 18 is opened and the power supply to the PTC ceramic 3 is stopped.

Note that, although the above-mentioned embodiments illustrate preferred embodiments of the present invention, the present invention is not limited thereto;
It can be implemented in various ways.

For example, in the embodiment shown in FIG.
The energization to the TC ceramic 3 was made to be intermittent, but as shown in FIG.
The three switches 18.4 are used as signals to drive the switches 18. 2
1.22 may also be used.

Further, in the embodiment shown in FIG. 1, an engine rotation switch 21 that responds to the engine rotation speed is used to detect complete explosion of the internal combustion engine, but instead of this switch 21, for example, an engine rotation switch 21 that detects negative pressure in the intake pipe is used. A negative pressure switch can also be used.

For example, when the intake pipe negative pressure reaches 60 mHg or more, the engine negative pressure switch may be closed as a complete explosion state.

However, in this case, there is a slight problem because the engine negative pressure switch is opened at high load when the opening degree of the throttle valve 12 is large, and the power supply to the PTC ceramic 3 is stopped.

In addition, in the embodiments shown in Figures 1 and 2, the power supply to the P100 ceramic 3 was stopped before the engine completely exploded.
A small amount of current may be applied to the PTC ceramic 3 through a resistance of about 1 to 10 Ω.

An example of this is shown in FIG. In FIG. 3, switch 21
The rest is the same as FIG. 1.

The engine rotation switch 21 includes a switch operating body 211, two fixed contacts 212, 213, and a resistor 214.

When the rotational speed of the internal combustion engine is below 400''' rpm,
The switch operating body 211 and the contact 213 are closed, and the current flowing through the switch 22 passes through the resistor 214.

When the rotational speed of the internal combustion engine exceeds 40 rpm, the switch operating body 211 and the contact 212 are closed, and the current flowing through the switch 22 does not pass through the resistor 214.

The above operation occurs when both switches 18 and 22 are closed, and if either switch 18 or 22 is open, no current will flow to switch 21 as well.

Further, although the PTC ceramic □ 3 is used as the electric heating element, a generally known heating element such as Ni--Cr or a Ni wire formed into a coil may also be used.

In the embodiment shown in FIG. 3, the following effects (1) and (2) can be newly obtained without significantly losing the effects of the embodiments shown in FIGS. 1 and 2.

■ If the difficulty in achieving a complete explosion is due to the low temperature of the intake air or intake pipe, this can be alleviated by passing a small current through the PTC ceramic.

■ When using PTC ceramic or Ni wire as an electrical heating element, the resistance at room temperature is small and a large current (this is called inrush current) usually flows as soon as the current starts flowing, but this inrush current value can be suppressed. , the lifespan of heating elements, batteries, switches, etc. can be improved.

As mentioned above, the present invention is configured so that even if the ignition switch is closed, the electrical heating element is not energized or the amount of current is reduced until the internal engine is fully detonated. Therefore, during cranking, the full voltage of the battery can be supplied to the starter, which has the great effect of making cranking easier. This has the great effect of reducing the risk of the battery dying.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention, and is a schematic cross-sectional view and electrical wiring diagram of an electric heating element and an intake pipe. FIGS. 2 and 3 are electrical wiring diagrams showing other embodiments of the present invention. 3... PTC ceramic that forms an electric heating element,
10... Heat riser part, 11... Intake pipe, 17... Cooling water, 18... Water temperature switch, 21... Engine response switch Engine rotation switch, 22...ignition switch, 23...battery.

Claims (2)

[Scope of utility model registration request] (1) An electric heating element that is provided in the intake pipe of the internal combustion engine and heats the intake air by electrical current supply, and operation of the internal combustion engine by controlling the current supply to the electric heating element. In an internal combustion engine equipped with an ignition switch for stopping the engine, an engine-responsive switch means is provided which is in an open state or a current limiting state when the internal combustion engine is not in a complete explosion state, and is closed when the engine is in a complete explosion state. A responsive switch means is electrically connected in series between the electric heating element and the ignition switch to control energization of the electric heating element depending on whether or not the internal combustion engine is fully detonated. An intake air heating device for internal combustion engines. (2) The intake air heating device for an internal combustion engine according to claim 1, wherein the engine responsive switch means is an engine rotation switch that is opened and closed by detecting the rotational speed of the internal combustion engine.