JPH0144779Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an intake air heating device used for heating the intake air of an internal combustion engine, and particularly to a flange-type intake air heating device attached to the intake inlet end of an intake manifold.

Conventional technology In order to improve the cold startability of diesel engines and reduce the amount of white smoke emitted during cold operation and deceleration operation,
It has been well known that it is effective to heat intake air with an intake air heating device, generally called an intake heater, provided in the middle of an intake passage. Intake air heating devices used for this intake air heating have been proposed in various forms in the past, one of which uses a ceramic plate heater such as a PTC heater made of a positive temperature coefficient thermistor with a lattice structure. are disclosed in Japanese Patent Application Laid-open No. 148658-1982, No. 182253-1983, and No. 25652-1988.

Ceramic plate heaters such as PTC heaters have a higher degree of freedom in shape than metal heaters, and are often placed across the intake passage to provide good ventilation and a large heat exchange surface area (heat generation surface area). In order to obtain this, the plate heater is formed in a lattice shape such as a square lattice or a honeycomb element, that is, a ventilation structure, and the smaller the lattice size, the larger the heat generating surface area of the plate heater.

In the above-mentioned intake air heating device, the larger the heat generating surface area of the plate heater, the more rapidly the intake air is heated. Although this is preferable for reducing white smoke emissions, the smaller the grid size of the plate heater due to its increased heat generating surface area, the greater the intake resistance during engine operation. During high-speed operation, the pressure drop in the engine intake system increases, causing a decrease in engine output.

If the configuration is such that all of the intake air always flows through the plate heater, a large amount of intake air will pass through the plate heater even during high-speed operation when intake air heating is not required, and the power consumption of the plate heater will significantly increase. As a result, power is wasted, and at this time, the filling efficiency is significantly reduced due to the intake resistance caused by the plate heater.

In order to avoid pressure loss in the engine intake system caused by the intake air heating heater, the intake air heating heater is provided movably between an active position where it crosses the intake passage and a standby position where it does not cross the intake passage. The heating heater is configured to be located at the retracted position, or a bypass intake passage is provided that bypasses the intake air heating heater disposed across the intake passage, and when the intake air is heated, the bypass intake passage is closed by a shutoff valve. Utility Model Application No. 55-110764 and Utility Model Application Publication No. 110764/1982 are configured to close the shutoff valve and open the shutoff valve when intake air heating is not required, such as during high-speed operation, so that the intake air flows through the bypass intake passage.
-139258, Utility Model No. 182253, Utility Model Kai No. 1882-
Proposed in No. 102765.

Problems to be Solved by the Invention Although the above-mentioned intake air heating device achieves the intended purpose, the movable intake air heating heater makes it troublesome to route electricity to the heater.
Furthermore, especially in the case of a fragile heater such as a heater made of ceramics, the risk of damage to the heater increases as the heater moves. The bypass intake passage system does not have the same problems as the movable heater type, but it does have the disadvantage of increasing the size of the internal combustion engine's intake system.

Means for Solving the Problems In view of the above-mentioned problems, the intake air heating device according to the present invention has a three-dimensional frame provided to be located in the intake passage, and each side formed by the frame has a PTC with lattice structure on all but some surfaces.
The present invention is characterized in that a plate-shaped heater such as a heater is provided, the part of the surface portion is a large opening, and the opening is configured to be selectively closed by a valve element.

Effects and Effects of the Invention According to the intake air heating device according to the invention, the opening is closed by the valve element when heating the intake air;
When heating the intake air is not necessary and pressure loss in the engine intake system becomes a problem, such as during high-speed operation, the valve element may be located in the open position and the opening portion may be opened, so that most of the intake air is heated when the intake air is heated. All of the air flows through the plate heater, which effectively heats the intake air. On the other hand, during high-speed operation, the intake air flows through the plate heater as well as through the opening, which heats the engine. Increased pressure loss in the intake system is avoided.

In addition, since the plate heater is arranged three-dimensionally within the intake passage, the total area of the plate heater is increased, so that the intake air can be heated effectively and rapidly using the heat generating surface area. Since the plate-shaped heaters are each fixedly arranged, there is no need to troubleshoot the process of energizing them, and there is little risk of damage to the plate-shaped heaters.

In addition, since the valve element is designed to open and close an opening on a part of the surface of a three-dimensional frame disposed in the intake passage, the intake air heating device according to the present invention is a bypass passage type intake air heating device. There is no need to increase the size of the intake system of the internal combustion engine.

Embodiment FIGS. 1 to 3 show an embodiment of the intake air heating device for an internal combustion engine according to the present invention. The intake air heating device 1 according to the present invention is connected in communication between the intake inlet end 52 of the intake manifold 51 and the connecting end 54 of the intake pipe 53 to the intake manifold 51. Therefore, intake air flows from the intake pipe 53 through the intake air heating device 1 into the intake manifold 51, and is thereby drawn into a combustion chamber (not shown) of the diesel engine 50.

The intake air heating device 1 includes an outer housing 3 having an intake passage 2 therein that communicates and connects an intake pipe 53 and an intake manifold 51, and an outer housing 3.
It has an inner heater holder 4 fixedly arranged inside.

The inner heater holder 4 includes a base flange 5 fixedly connected to the outer housing 3 and a frame 6 erected from one side of the base flange and positioned within the outer housing 3. The frame body 6 has relatively large intake passage openings 7 and 8 on one front face and four side faces, and each of the four intake passage openings 8 has a rectangular plate shape with a lattice structure. PTC heater 9 is installed.

A valve shaft 10 is connected to the intake passage 2 in the outer housing 3.
The valve shaft 10 carries a plate-shaped valve element 11 at a portion aligned with the intake passage opening 7 . By rotation of the valve shaft 10, the valve element 11 opens the intake passage opening 7 as shown in FIG.
The valve is moved between a closed position in which the valve is closed and an open position in which communication with the intake passage opening 7 is established as shown in FIG. A drive lever 12 is attached to one end of the valve stem 10, and the drive lever is connected to a rod 14 of a diaphragm device 13.
The drive is connected to the

The diaphragm device 13 drives the valve element 11 to the closed position as shown in FIG. 2 when a negative pressure of a predetermined value or more is not introduced into the diaphragm chamber; When negative pressure is introduced, the valve element 11 is driven to the open position as shown in FIG.

The diaphragm chamber of the diaphragm device 13 is connected to port a of the solenoid valve 15. Solenoid valve 15
In addition to port a, it has a negative pressure port b connected to the negative pressure pump 16 and an atmospheric pressure port c opened to the atmosphere. When energized, port a is connected to negative pressure port b, and this On the other hand, when power is not supplied, port a is connected to port c instead of port b. Therefore, when the electromagnetic valve 15 is energized, a negative pressure of a predetermined value or more is introduced into the diaphragm chamber of the diaphragm device 13 and the valve element 11
is located in the valve open position, and when the electromagnetic valve 15 is not energized, atmospheric pressure is introduced into the diaphragm chamber of the diaphragm device 13, and the valve element 11 is located in the valve closed position.

The PTC heater 9 is configured to be selectively supplied with current from a battery power source 20 via a heater electric switch 21.

Control of energization to the solenoid valve 15 and opening/closing of the heater electric switch and indicator lamp electric switch 23 are performed by an electric control device 24 including a microcomputer according to a flowchart as shown in FIG. 4 or FIG. It is becoming more and more common to do so.

The flowchart shown in FIG. 4 starts when the key switch 25 is turned on by inserting the engine key into the keyhole.

In the first step 1, the engine cooling water temperature Tw detected by the water temperature sensor 26 is set to a predetermined value.
A determination is made as to whether or not it is lower than Twset. Tw≦
When Twset is set, that is, at cold start, step 2
On the other hand, if Tw≦Twset does not hold, proceed to step 5.

In step 2, switch the heater electric switch 2.
1 and also closes the electric lamp switch 23. As a result, each of the PTC heaters 9 is energized, and the PTC heaters 9 generate heat.
Further, the indicator lamp 22 is lit to inform the driver that the intake air is being preheated.

At this time, since the electromagnetic valve 15 is not energized, the valve element 11 is located in the closed position as shown in FIG. 2 and closes the intake passage opening 7.
Therefore, at this time, substantially all of the intake air flowing from the intake pipe 53 toward the intake manifold 51 flows through the PTC heater 9, and the intake air is heated effectively and rapidly by the PTC heater 9.

After step 2, the process advances to step 3, and in step 3, it is determined whether a predetermined time _t1 has elapsed since the electric heater switch 21 was closed, that is, from the start of energization to the PTC heater 9. A determination is made. When the predetermined time _t1 has not elapsed, this step 3 is repeatedly executed, and when the predetermined time _t1 has elapsed, the process proceeds to the next step 4.

In step 4, the lamp electric switch 2
3 is opened. As a result, the indicator lamp 22 turns off, and the driver is notified that the intake air preheating has been completed. After step 4, proceed to step 5.

In step 5, it is determined from the on/off signal of the starter switch 27 whether or not starting of the diesel engine 50 by the starter has been completed. If the engine starting is not completed, this step 5 is repeatedly executed, and when the engine starting is completed, the process proceeds to the next step 6.

In step 6, turn on heater electric switch 2.
1 is closed, that is, whether or not the PTC heater 9 is energized. When the heater electric switch 21 is closed, the process proceeds to step 7, whereas when the heater electric switch 21 is open, the process proceeds to step 9.

In step 7, it is determined whether a predetermined time _t2 has elapsed after the engine starting is completed. If the predetermined time t ₂ has not elapsed, this step 7 is repeatedly executed, whereas if the predetermined time t ₂ has elapsed, the process proceeds to the next step 8.

In step 8, the heater electric switch 2
1 is opened and the solenoid valve 15 is energized. As a result, the power supply to the PTC heater 9 is stopped, and the negative pressure generated by the negative pressure pump 16 is introduced into the diaphragm chamber 13, thereby moving the valve element 11 to the valve open position as shown in FIG. position, and the intake passage opening 7 is opened. That is,
When the power supply to the PTC heater 9 is stopped and heating of the intake air by the PTC heater 9 is completed, the intake passage opening 7 is opened to avoid a pressure drop in the engine intake system caused by the PTC heater 9.

After step 8, the process advances to step 9, in which it is determined whether the key switch 25 is in the on state. When the key switch is on, step 9 is repeatedly executed; on the other hand, when the key switch is not on, that is, when the engine is stopped, the process proceeds to step 10.

In step 10, power supply to the solenoid valve 15 is stopped. As a result, the diaphragm device 1
Atmospheric pressure is introduced into the diaphragm chamber 3, and the valve element 11 is placed in the closed position as shown in FIG. 2, closing the intake passage opening 7.

The flowchart shown in FIG. 5 shows another example of intake air heating control by the flowchart shown in FIG. 4, and this flowchart also shows that the engine key is inserted into the keyhole. The process starts when the key switch 25 is turned on. Incidentally, since steps 1 to 5 in this flowchart are the same as the flowchart shown in FIG. 4, their explanation will be omitted, and the explanation will start from step 6.

In step 6, it is determined whether or not the heater switch 21 is closed. If the heater electric switch 21 is closed, the process proceeds to step 11, whereas if the heater electric switch 21 is not closed, the process proceeds to step 18.

In step 11, it is determined whether the rotational speed Ne of the diesel engine 50 detected by the rotational speed sensor 28 is greater than a predetermined value Neset. When Ne≧Neset, that is, during high-speed operation, the process proceeds to step 12, whereas Ne≧Neset
If not, that is, if it is not during high-speed operation, the process advances to step 14.

In step 12, the electromagnetic valve 15 is energized and the flag F is set to 1. As a result, even when the intake air is being heated after the engine is started, the valve element 11 is opened during high-speed operation, and most of the intake air flows through the intake passage opening 7. This prevents pressure loss in the engine intake system from increasing, and also prevents a large amount of intake air from flowing through the PTC heater 9, thereby avoiding wasteful power consumption in the PTC heater 9.

After step 12, proceed to step 13. In step 13, it is determined whether a predetermined time _t2 has elapsed since the start of the diesel engine 50 was completed. If the predetermined time _t2 has not elapsed, the process returns to step 11, whereas if the predetermined time _t2 has elapsed, the process proceeds to the next step 16.

In step 14, it is determined whether flag F is 1 or not. When F=1, that is, when the valve element 11 is open, step 15
On the other hand, if F is not 1, the process proceeds to step 13.

In step 15, the electromagnetic valve 15 is de-energized and the flag F is set to zero. As a result, when the engine is not operating at high speed, the valve element 11 closes and the intake passage opening is closed.

In step 16, the electric heater switch 21 is opened. As a result, the power supply to the PTC heater 9 is stopped, and intake air heating ends.

After step 16, the process advances to step 17, in which it is determined whether flag F is 1 or not. When F=1, the process proceeds to step 19, whereas when F=1, the process proceeds to step 18.

In step 18, the solenoid valve 15 is energized and the flag F is set to 1. As a result, the valve element 11 is placed in the open position as shown in FIG. 3, and the intake passage opening 7 is opened.

In step 19, it is determined from the change in the rotational speed of the diesel engine 50 detected by the rotational speed sensor 28 whether or not the diesel engine 50 is in deceleration operation. When decelerating operation is in progress, the process proceeds to step 20, whereas when decelerating operation is not in progress, the process proceeds to step 23.

In step 20, it is determined whether the intake air temperature Ti detected by the intake air temperature sensor 29 is lower than a predetermined value Tiset. When Ti≦Tiset, that is, when the temperature is low, the process proceeds to step 21, whereas when Ti≦Tiset, the process proceeds to step 23.

In step 21, it is determined whether the flag F=0. When F=0, the process proceeds to step 25, and when F=0, the process proceeds to step 22.

In step 22, the electric heater switch 21 is closed, the electromagnetic valve 25 is energized, and the flag F is set to 0. That is,
In step 22, in order to prevent the amount of white smoke from increasing during deceleration operation at low temperatures, the PTC heater 9 is energized to start heating the intake air, and the PTC heater efficiently heats the intake air. The opening 7 for the intake passage is formed by the valve element 11.
is closed.

In step 23, it is determined whether the flag F is 0 or not. When F=0, the process proceeds to step 24, whereas when F=0, the process proceeds to step 25.

In step 24, the heater electric switch 21 is opened and the electromagnetic valve 15 is energized in order to end intake air heating during low-temperature deceleration. Also, in step 24, flag F is set to 1.

In step 25, it is determined whether the key switch 25 is in the on state. When the key switch 25 is on, the process returns to step 19, whereas when the key switch 25 is not on, that is, when the engine is stopped, the process proceeds to step 26.

In step 26, it is determined whether flag F is 1 or not. When the flag F=1, the process proceeds to step 27, whereas when the flag F=1, the process proceeds to step 28.

In step 27, the energization to the solenoid valve 15 is stopped.

In step 28, the electric heater switch 21 is opened.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto, and various embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a partially sectional plan view of the intake system of a diesel engine equipped with an intake air heating device according to the present invention, and FIGS. 2 and 3 are perspective views showing main parts of the intake air heating device according to the present invention. 4 and 5 are flowcharts showing the control procedure for the intake air heating device according to the present invention. 1...Intake heating device, 2...Intake passage, 3...
Outer housing, 4... Inner heater holder,
5... Base flange, 6... Frame body, 7, 8...
Intake passage opening, 9...PTC heater, 10...
Valve shaft, 11... Valve element, 12... Drive lever, 1
3...Diaphragm device, 14...Rod, 15
... Solenoid valve, 16 ... Negative pressure pump, 20 ... Battery power supply, 21 ... Electric switch for heater, 22
... Indicator lamp, 23 ... Electric switch for lamp, 24 ... Control device, 25 ... Key switch, 26 ... Water temperature sensor, 27 ... Starter switch, 28 ... Rotation speed sensor, 29 ... Intake temperature sensor, 50... Diesel engine, 51... Intake manifold, 52... Intake inlet end, 53...
Intake pipe, 54... connection end.

Claims (1)

[Scope of utility model registration request] It has a three-dimensional frame provided to be located in the intake passage, and a plate-shaped heater with a lattice structure is provided on each surface of the frame except for a part of the surface, An intake air heating device for an internal combustion engine, characterized in that a surface portion of the portion is a large opening, and the opening is configured to be selectively closed by a valve element.