JPH0331510A - Heater with catalyst and its control method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) The present invention is equipped, for example, in the exhaust system of an automobile engine, and activates a catalyst for purifying exhaust gas and purifies the exhaust gas. The present invention relates to a heater with a catalyst that passes through and purifies the heater, and a method of controlling the same.

(Prior Art) For example, some automobiles are equipped with a catalytic converter in their exhaust system to purify harmful components in exhaust gas, such as unburned hydrocarbons. That is, in a catalytic converter, a catalyst formed by supporting a catalytic metal such as platinum or rhodium on a monolith type carrier is disposed and housed inside a converter container. The catalytic converter then circulates the exhaust gas into the converter container and passes the exhaust gas through the catalyst.

Further, the catalytic converter uses the thermal energy of the exhaust gas to raise the temperature of the catalyst and activate it. The catalytic converter then uses the activated catalyst metal to purify harmful components such as unburned hydrocarbons (HC), -carbon oxides (CO), and nitrogen oxides (NOx) in the exhaust gas. Let it flow.

(Problems to be Solved by the Invention) By the way, in a vehicle equipped with the above-mentioned catalytic converter, the temperature of exhaust gas pumped from the engine gradually increases after the engine is started.

For this reason, the catalyst may not be sufficiently activated during a cold start such as during warm-up operation.

An object of the present invention is to activate the entire catalyst in a short time and to purify exhaust gas more fully.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to achieve the above object, the present invention provides the following features:
Catalytic chemicals are supported on the heating element (7 catalyst heaters are turned on)
When the heating element of the catalytic heater reaches a temperature sufficient to activate the catalyst chemical, the catalytic heater is raised, and the catalytic heater is placed in the exhaust gas upstream of the catalyst for exhaust gas purification. After the catalyst is fully activated, the catalyst-equipped heater is laid down.
and a step of turning it off.

Further, the present invention includes a heating element that generates heat when energized and a catalyst chemical that is heated by the heating element supported on the heating element, and provides a portion near the exhaust gas purifying catalyst in the exhaust gas flow path. It is installed so that it can be folded down and raised freely, and is stowed when folded down, and when stood up, it faces the exhaust gas purification catalyst and heats the exhaust gas by passing the exhaust gas pumped from the vehicle engine towards the catalyst. I decided to do so.

By doing this, the present invention utilizes the thermal energy of the catalyst-equipped heater to raise the temperature of the catalyst, activating the entire catalyst in a short time, and also purifies the exhaust gas with the catalyst-equipped heater. Allows for more thorough purification.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

FIG. 1 shows an embodiment of the present invention, and numeral 1 in the figure is a catalytic converter. This catalytic converter 1 is installed, for example, in the exhaust system of an automobile, and includes a converter container 2 that allows exhaust gas to flow in the axial direction, as indicated by an arrow A, and a converter container 2 that is disposed within the converter container 2 and allows the exhaust gas to pass through the converter container 2. and a catalyst 3 for purification. The catalytic converter 2 holds the catalyst 3 in the converter container 2 via the holding layer 4 .

Further, 5 in the figure indicates a heater with a catalyst (hereinafter referred to as a heater). As shown in FIG. 2, this heater 5 is made up of a circular frame-shaped body 6 and a single nichrome wire 7 as a heating element attached thereto. And the heater 5 is
The nichrome wire 7 is meandering in an S-shape, and the nichrome wire 7
Most of it is exposed inside the main body 6. The heater 5 has most of the nichrome wires 7 arranged in parallel inside the main body 6.

In addition, the heater 5 is attached to the part of the nichrome wire 7 exposed inside the main body 6, as shown in the figure with a part enlarged and emphasized.
A catalyst metal 8 such as platinum or rhodium is supported. The heater 5 is configured to generate heat in the nichrome wire 7 by applying electricity to the nichrome wire 7, thereby heating the catalyst metal 8 . The heater 5 activates the catalyst metals 8 by generating heat in the nichrome wire 7.

Further, the heater 5 is disposed upstream of the exhaust gas A of the converter container 2, and has one end pivotally supported within the exhaust gas passage 9. As shown in FIG. 1, the heater 5 is horizontal to the flow direction of the exhaust gas A, and as shown by a two-dot chain line B, the heater 5 is It is now possible to stand up in a nearly vertical position. When the heater 5 is laid down, it is stored in a storage space 10 provided in the exhaust gas passage 9.

Furthermore, when the heater 5 stands up, it is rotationally displaced so as to approach the catalyst 3 side. After standing up, it faces substantially parallel to the exhaust gas upstream side surface 3a of the catalyst 3. The heater 5 causes the exhaust gas A flowing toward the catalyst 31 to pass through the inside of the main body 6 before flowing into the catalyst 3. Here, the size of the heater 5 is set so that it occupies most of the area of the exhaust gas passage 9 when it stands up.

That is, when the heater 5 is erected, the exhaust gas A is passed through the inside of the heater 5, and the heater 5 is heated by the reaction heat of the heated nichrome wire 7 and the catalyst metal 8 that has started the reaction. Then, the heated exhaust gas A is circulated to the catalyst side and passed through the catalyst 3.

Then, the catalyst 3 is heated and activated by the thermal energy of the exhaust gas A pumped from the engine and the thermal energy of the nichrome wire 7.

Further, the heater 5 purifies the exhaust gas A using the catalyst metal 8 supported on the nichrome wire 7.

Then, the exhaust gas A reaches the catalyst 3 and removes harmful components such as unburned hydrocarbons (HC), -carbon oxides (CO), and nitrogen oxides (NOx) from the exhaust gas A flowing toward the catalyst 3. Purify and reduce to some extent before doing so.

Further, when the heater 5 is laid down, almost the entirety of the heater 5 enters the inside of the storage space 10. Further, when the heater 5 is laid down, it does not protrude into the exhaust gas passage 9 and disturb the flow of the exhaust gas A.

Next, one embodiment of the method for controlling the heater 5 will be described using the flowchart shown in FIG.

As shown in FIG. 3, the heater 5 is normally laid down and stored in the storage space 10. For example, when a door key is inserted into a door of a car to unlock the door, the heater 5 in the laid down state is turned on, causing the nichrome wire 7 to generate heat. Furthermore, if the engine is started when the heater 5 is turned on, the heater 5 is turned on based on the output of a timer circuit or the like.
X seconds after turning ON, the heater 5 is rotated and erected.

Further, if the engine is not started even after y seconds have elapsed since the heater 5 was turned on, the heater 5, which remains in the collapsed state, is turned off. Then, when the engine is started after that, the heater 5 is turned on, and the heater 5 is turned on after X seconds. Here, the above-mentioned X seconds is set to the time required for the catalyst metal 8 of the heater 5 to be sufficiently heated and activated.

Note that the timing for turning on the heater 5 may be set, for example, when the power of the electrical system is turned on before starting the herring, or at the same time as the starting of the engine. In addition, the timing for raising the heater 5 is set to
However, the temperature may be set when the temperature reaches α° C. or higher, which is sufficient to heat the catalyst 3 efficiently.

Also, after 2 seconds have passed since the heater 5 was turned on,
The heater 5 is laid down, and then the heater 5 is turned off.

Note that, for example, immediately after turning off the heater 5,
It may also be made to lie down. Further, the above-mentioned 2 seconds is set to the time required for the catalyst 3 to be sufficiently activated by the exhaust gas A, the heat of the heater 5, and the like.

Here, the timing for turning down the heater 5 to 0FFL is as follows:
For example, based on the output of an exhaust temperature sensor disposed near the exhaust gas upstream side of the catalyst 3 or near the exhaust gas downstream side, the temperature of the exhaust gas A is set to a value β° C. that allows the catalyst 3 to be sufficiently activated. It may be set when it is determined that the above temperature has been reached, or when it is determined that the water temperature, which increases after starting the engine, has reached γ° C. or higher based on the output of the water temperature sensor. Note that the value of γ° C. is set, for example, to the value of the water temperature at the end of engine warm-up.

Furthermore, the timing to lower the heater 5 to 0FFL is determined by an exhaust gas sensor or HC sensor, etc. disposed on the exhaust gas downstream side of the catalyst 3, or when it is determined that the catalyst 3 is sufficiently activated, or when the engine is turned off. You can also set it when it is stopped.

The heater 5 as described above is located close to and opposed to the catalyst 3 during a cold start of the engine, and directs the exhaust gas A flowing toward the catalyst 3 to the energized nichrome wire 7 or the nichrome wire 7. Since it is heated by the heat of reaction of the supported catalyst metals 8, etc., the catalyst 3 can be sufficiently activated in a short time.

Furthermore, the heater 5 allows the exhaust gas A to pass inside the main body 6 and is purified by the catalyst metal 8 before reaching the catalyst 3. components can be reduced.

In addition, since the heater 5 is turned on after reaching a temperature sufficient to raise the temperature of the catalyst 3, the thermal energy of the exhaust gas during a cold start is transferred to the heater 5 which has not yet generated sufficient heat. There is no possibility of losing money. Therefore, the catalyst 3 can be activated even earlier.

Furthermore, since the heater 5 is turned on before or at the same time as the engine starts, the heater can generate enough heat, and this also makes it possible to sufficiently activate the catalyst 3 in a short time. can.

Further, since the heater 5 is housed after the catalyst 3 is sufficiently activated, pressure loss in the exhaust gas A due to the heater 5 can be prevented. Furthermore, since the high-temperature exhaust gas A is not blown onto the heater 5, the durability of the heater 5 is high.

In this embodiment, the nichrome wire 7 is used as the heating element, but the present invention is not limited to this, and a material other than the nichrome wire 7 may be used as the heating element.

〔Effect of the invention〕

As explained above, the present invention includes a process of turning on a catalyst-equipped heater having a catalyst chemical supported on a heating element, and a process of activating the catalyst chemical by the catalyst-equipped heater's heating element, before starting a vehicle engine. The process of raising the heater with a catalyst when a sufficient temperature has been reached, and also placing the heater with a catalyst to face the catalyst on the exhaust gas upstream side of the catalyst for exhaust gas purification, and after the catalyst has been sufficiently activated. The method includes a step of inclining the catalyst-equipped heater and turning it off.

Further, the present invention provides a heating element that generates heat when energized, and a catalyst chemical that is heated by a heating element supported on the heating element, and a portion near the exhaust gas purifying catalyst in the exhaust gas flow path. It is installed so that it can be folded down and raised freely, and is stowed when folded down, and when stood up, it faces the exhaust gas purification catalyst and heats the exhaust gas by passing the exhaust gas pumped from the vehicle engine towards the catalyst. I decided to do so.

Therefore, the present invention has the effect that the entire catalyst can be activated in a short time and that exhaust gas can be purified more fully.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, FIG. 2 is a front view showing a heater with a catalyst, and FIG. 3 is a flowchart showing a method of controlling the heater with a catalyst. 3... Catalyst, 5... Heater with catalyst, 7... Nichrome wire (heating element), 8... Catalyst metal, A... Exhaust gas. Figure 1

Claims (2)

[Claims] (1) Before starting the vehicle engine, a process of turning on a catalyst-equipped heater having a catalytic agent supported on a heating element, and raising the temperature of the catalytic heater's heating element to a temperature sufficient to activate the catalytic agent. a step of standing up the heater with a catalyst when the catalyst reaches the exhaust gas purifying catalyst and facing the catalyst on the exhaust gas upstream side of a catalyst for purifying exhaust gas; A method for controlling a heater with a catalyst, comprising the steps of lowering the heater with a catalyst and turning it off. (2) Consisting of a heating element that generates heat when energized and a catalyst chemical that is heated by the heating element supported on this heating element, it lies down in the vicinity of the exhaust gas purifying catalyst in the exhaust gas flow path. It is provided so as to be able to stand up freely, and is stored when it is laid down, and when it is stood up, it faces the catalyst for exhaust gas purification, and heats the exhaust gas by passing the exhaust gas that is force-fed from the vehicle engine toward the catalyst. A heater with a catalyst characterized by: