JPH09272328A - Heating apparatus for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control NOx without any complicated control by reducing NOx in exhaust gas through reduction catalyst so as to control. SOLUTION: Reduction catalyst 4 and oxidation catalyst 8 are installed in series in an exhaust pipe E5 constituting an exhaust flow path of a diesel engine E and an HC supply means and EC atomization means 2 are provided between the exhaust pipe E5 and the reduction catalyst 4. The reduction catalyst 4 is composed of zeolitic catalyst having NOx reduction action or noble metal catalyst such as platinum. The HC supply means is composed of a fuel injection valve and the HC atomization means 2 is composed of an ultrasonic vibrator, etc. An air supply means 6 is connected between the reduction catalyst 4 and the catalyst 8. The air supply means 6 is composed of a westco pump, or the like. The catalyst 8 is composed of metal oxide based catalyst having oxidation action or the noble metal catalyst such as platinum. A first heat exchanger 9 is formed around the circumference of the catalyst 8 and heat exchanged with circulating water for cooling engine. The exhaust gas treated by heat exchange is exhausted from the exhaust pipe 10 constituting the exhaust flow path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use in a vehicle equipped with an internal combustion engine, such as a diesel engine, and a catalytic exhaust gas purifying apparatus for an internal combustion engine for reducing and decomposing NO _x contained in exhaust gas. The present invention relates to an exhaust gas purifying and vehicle interior heating device that functions both as an auxiliary heating device.

[0002]

2. Description of the Related Art First, a conventional technique for purifying NO _X contained in exhaust gas of an internal combustion engine will be described. As a conventionally used method, there is a method of reducing NO _x by providing a reduction catalyst in the exhaust passage, which is widely used in gasoline engine vehicles. Generally, the activity of the reduction catalyst remarkably decreases in an atmosphere of excess oxygen, so gasoline vehicles equipped with a reduction catalyst use an electronically controlled fuel injection device, etc. to throttle open so that oxygen does not remain in the exhaust gas. The fuel injection amount is controlled according to the degree. On the other hand, in the case of a vehicle using a diesel engine, since there is no throttle and the output is controlled only by the fuel injection amount, a large amount of oxygen remains in the exhaust gas and NO _X purification cannot be performed.

As a countermeasure against this, HC is contained in the exhaust gas.
A method of adding is known. FIG. 6 shows a system disclosed in Japanese Patent Laid-Open No. 4-330314 as a first conventional example. This system is a diesel engine 6
01, a copper zeolite-based catalyst 603 that is a reduction catalyst provided in the exhaust flow path 602, a fuel injection unit 605 that sprays HC into the exhaust gas, an HC sensor 604 that measures the HC concentration in the exhaust gas, and controls them. Control means 607 for
It is composed of a fuel tank 606 and is intended to purify NO _x by spraying HC as a reducing agent in the exhaust gas.

A second conventional example is Japanese Patent Laid-Open No. 48-8.
7219 and JP-A-63-61708. In this method, a three-way catalyst is used as a catalyst, and HC is added to the exhaust gas in order to remove O ₂ which deteriorates the activity of the three-way catalyst from the exhaust gas. Further, as a conventional example, an auxiliary heating device for a diesel engine vehicle will be described.

Generally, the heating of a vehicle using an internal combustion engine is performed by using the waste heat of the internal combustion engine, but the diesel engine has good thermal efficiency and a small amount of waste heat, so that the heating capacity may be insufficient. Therefore, a combustion heater may be installed as an auxiliary heating device. FIG. 7 shows a conventional system equipped with a combustion heater. This is the flow path P of the circulating water that cools around the cylinder E1 of the diesel engine E.
A combustion heater 700 is provided in each of P3, P4, and P5. The combustion heater 700 includes an air supply unit 701, a fuel supply unit 702, a combustion cylinder 703, and a heat exchanger 704 for exchanging heat between circulating water and combustion gas. And consists of. Combustion heater 70
When 0 burns, the heat of combustion raises the temperature of the circulating water. A heater core 11 is placed in the vehicle compartment to exchange hot water with the air entering the vehicle compartment to send warm air into the vehicle compartment.

[0006]

First, the problem of the exhaust gas purifying apparatus will be described. In the above conventional exhaust gas purifying apparatus, when HC is supplied in an amount more than that required for NO _X purification, the excessively supplied HC passes through the catalyst without being reacted and is discharged into the atmosphere, which causes a new pollution problem. It may occur. Therefore, the HC concentration in the exhaust gas as in the case of the first conventional example and the O ₂ concentration in the exhaust gas as in the case of the second conventional example are precisely measured, and the required HC supply amount is strictly determined. Had to control.

[0007] Next, the problem relating to the auxiliary heating device will be explained. If a system which has not been used conventionally such as a combustion heater as the auxiliary heating device is newly added as described above, the system is upsized and the cost is increased. The problem arises. It is an object of the present invention to provide an exhaust gas purifying and vehicle interior heating device that enables NO _x purification of an internal combustion engine, for example, a diesel engine, without complicated control, and that can also solve insufficient heating capacity.

[0008]

In order to achieve the above object, the present invention adopts the configurations described in claims 1 to 5. According to the first aspect, the HC supplied by the HC supply means passes through the reduction catalyst to reduce and purify NO _X in the exhaust gas. The unreacted HC is mixed with the air supplied by the air supply means and passes through the oxidation catalyst, where it reacts and burns to be converted into harmless CO ₂ and H ₂ O.
The combustion heat at this time is heat-exchanged between the exhaust gas and the circulating water by the first heat exchanger, and is further exchanged between the circulating water and the air supplied into the vehicle compartment by the second heat exchanger. It is exchanged and used for heating the passenger compartment.

With this, without complicated control,
There is an effect that it is possible to provide an exhaust gas purifying and vehicle interior heating device that makes it possible to purify NO _{X of an} internal combustion engine and further solve a heating capacity shortage. According to claim 2, the NO _x and HC purification reaction in the exhaust gas is the same as in the case of claim 1, but the combustion heat of HC is supplied to the exhaust gas and the passenger compartment by the third heat exchanger. The heat is directly exchanged with the air used for heating the passenger compartment.

As a result, only one heat exchanger is required, which has the effect of simplifying the apparatus. According to claim 3, H
Since the amount of HC supplied from the C supply means is controlled to a required amount, there is an effect that fuel consumption can be suppressed.
According to the fourth aspect, the control means calculates and controls the amount of HC burned by the oxidation catalyst from the water temperature of the circulating water or the temperature of the air supplied to the vehicle interior and the required heating capacity, so that a comfortable heating effect is obtained. Is obtained.

According to the fifth aspect, the necessary HC supply amount is calculated from the rotation speed of the internal combustion engine and the fuel supply amount to the internal combustion engine, so that there is an effect that the control becomes easy.

[0012]

1 and 2 relate to a first embodiment of the present invention. FIG. 1 is an overall configuration diagram, and FIG.
3 is a flowchart showing the operation of the first embodiment. In FIG. 1, a reduction catalyst 4 and an oxidation catalyst 8 are mounted in series on an exhaust pipe E5 that forms an exhaust flow path of a diesel engine E, and an HC supply unit 1 and an HC atomizer are provided between the exhaust pipe E5 and the reduction catalyst 4. There is means 2. Reducing catalyst 4 is composed of a noble metal catalyst zeolitic catalyst or platinum with NO _X reduction action. The HC supply means 1 is composed of a known fuel injection valve, and the HC atomization means 2 is composed of a known ultrasonic transducer.

Air supply means 6 is connected between the reduction catalyst 4 and the oxidation catalyst 8. The air supply means 6 is composed of a known Wesco pump or the like. The oxidation catalyst 8 is composed of a metal oxide catalyst having an oxidizing action or a noble metal catalyst such as platinum. A first heat exchanger 9 is formed around the oxidation catalyst 8 to exchange heat with circulating water for cooling the engine. The heat-exchanged exhaust gas is exhausted from the exhaust pipe 10 forming the exhaust flow path.

The HC supply means 1, the HC atomization means 2, and the air supply means 6 are controlled by the control means 15. Further, a signal from the water temperature sensor 16 and the engine control means E3 and a signal of the position of the temperature control lever 12 are input to the control means 15. A water jacket E4 is formed around the cylinder E1 of the diesel engine E, and circulating water for cooling flows. Circulating water passes through the radiator E6, or when the water temperature is too low, the valve E
After bypassing the radiator by 7 and the pipe P2, the heat is exchanged with the exhaust gas by the first heat exchanger 9 through the pipes P3 and P4.

The circulating water that has passed through the first heat exchanger 9 passes through the pipe P5, passes through the heater core 11 that constitutes the second heat exchanger provided in the duct 111, and is sent into the vehicle interior by the blower 112 and the blower motor 113. Heats the interior of the vehicle by exchanging heat with air. The circulating water exiting the heater core 11 returns to the water jacket E4 via the pipe P6. The circulating water is circulated by a pump E8 driven by a diesel engine E.

The diesel engine E has a fuel injection pump E2, which is controlled by the engine control means E3. Further, the fuel is sent from the tank 13 by the fuel pump 14 to the fuel injection pump E2. Next, the operation of the system shown in FIG. 1 will be described with reference to the flowchart shown in FIG. In step F1, the control unit 15 receives signals from the engine control unit E3 and signals regarding the engine speed and the fuel injection amount. Then, in step F2, the HC concentration in the exhaust gas is estimated from those signals by a predetermined calculation formula or map to obtain the required HC.
The supply amount V1 is calculated. Further, in step F3, the signal of the existing water temperature sensor 16 for engine control and the position of the temperature control lever 12 are detected. Then, from these, in step F4, the HC combustion amount V2 for obtaining the required heating capacity by burning with the oxidation catalyst 8 is obtained. Then, in step F5, the control means 15 sends a command to the HC supply means 1 so as to supply HC by the amount obtained by adding V1 and V2 obtained above. The supplied HC is atomized by the HC atomizing means 2, becomes HC gas by the heat of the exhaust gas at the position of the exhaust passage 3 in FIG. 1, and enters the reduction catalyst 4. Here, in the exhaust gas because it contains sufficient HC to reduce NO _X, NO _X is purified.

Next, air is blown from the reduction catalyst 4 into the exhaust gas at the position of the exhaust passage 5 in FIG. 1 by the air supply means 6 at the position of the exhaust passage 7 in FIG. The amount of air blown in is calculated according to a calculation formula or a map determined in advance in step F6. According to the calculated value, the amount of air required to burn HC by V2 in step F7 is supplied to the position of the exhaust passage 7 by the air pump 6 which is an air supply means.

Here, the combustion by the oxidation catalyst 8 is lean.
Since it is possible in a wide range of air-fuel ratio range, the sensor
There is no need to measure the air flow rate and strictly control the air flow rate.
It is sufficient to estimate the required air flow rate from the supply amount, so
Complete combustion of HC without precise control of air supply
be able to. With the above control, NO is reduced by the reduction catalyst 4. _X
Of the high temperature combustion gas while purifying HC with the oxidation catalyst 8.
To exchange heat with circulating water or air supplied to the interior of the vehicle,
The room can be heated.

That is, according to the present invention, the HC sensor, O
_It is possible to provide an excellent exhaust gas purification and vehicle interior heating device that enables reduction and purification of NO _X without strictly controlling the HC supply amount using a _2- sensor or the like and that also functions as auxiliary heating. FIG. 3 is an overall configuration diagram showing a second embodiment of the present invention. In the first embodiment shown in FIG. 1, the circulating water for engine cooling and the circulating water for heating are integrated.
In the second embodiment shown in (1), circulating water for engine cooling and circulating water for heating are separately configured. That is, FIG.
In the second embodiment shown in FIG. 1, the first heat exchanger 9 around the oxidation catalyst 8 is a circulating water system including a pipe P500, a heater core 11 forming a second heat exchanger, a pipe P600, and a circulating water pump 17. It is connected and independent of the circulating water system for engine cooling. The water temperature sensor 16 that determines the amount of HC to be supplied for heating is provided in the pipe P600.

FIG. 4 is an overall configuration diagram showing a third embodiment of the present invention. In the first and second embodiments shown in FIGS. 1 and 3, the heat exchanger between the exhaust gas and the circulating water is connected to the oxidation catalyst 8
However, in the third embodiment shown in FIG. 4, the heat exchanger is provided around the exhaust passage. That is, in the third embodiment shown in FIG. 4, the heat exchanger P40
0 is provided around the exhaust pipe 10.

FIG. 5 is an overall configuration diagram showing a fourth embodiment of the present invention. First to third shown in FIGS. 1 to 4
In the fourth embodiment, the circulating water is used for heating the passenger compartment, but in the fourth embodiment shown in FIG.
The exhaust gas-air heat exchanger 901 is provided as the heat exchanger of No. 1, and the air that enters the vehicle interior is directly warmed. That is, in the fourth embodiment shown in FIG. 5, the high-temperature exhaust gas emitted from the oxidation catalyst 8 enters the exhaust gas-air heat exchanger 901 which is the third heat exchanger, and the third heat exchanger 901. Heat-exchanges between the air entering from the intake port 931 and the exhaust gas by the fins 911 and 921, and sends the heated air into the vehicle interior by the blower fan 12 and the blower motor 113 to perform heating. In the fourth embodiment, the blower fan 12 that sends air into the vehicle interior also has a function of sucking air into the third heat exchanger 901.
The temperature of the air sucked from 31 is measured by the temperature sensor 18 and input to the control means 15.

As described above, according to the present invention, it is possible to provide an excellent system capable of purifying NO _{X of} an internal combustion engine without complicated control and solving the shortage of heating capacity.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a first embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the first embodiment.

FIG. 3 is an overall configuration diagram showing a second embodiment of the present invention.

FIG. 4 is an overall configuration diagram showing a third embodiment of the present invention.

FIG. 5 is an overall configuration diagram showing a fourth embodiment of the present invention.

FIG. 6 is an overall configuration diagram showing a system of a first conventional example.

FIG. 7 is an overall configuration diagram showing a conventional system including a combustion heater.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 HC supply means (fuel injection valve) 4 Reduction catalyst 6 Air supply means (Wesco pump) 8 Oxidation catalyst 9,900 1st heat exchanger 901 3rd heat exchanger (exhaust gas-air heat exchanger) 11th 2 heat exchanger (heater core) 12 means for setting required heating capacity required by passengers (temperature control lever) 15 control means 16, 18 temperature sensor (water temperature sensor) E internal combustion engine (diesel engine)

Claims (5)

[Claims] 1. A reduction catalyst and an oxidation catalyst provided in an exhaust passage of an internal combustion engine, and an exhaust passage between an exhaust port of the internal combustion engine and an inlet of the reduction catalyst for purifying NO _x. An HC supply means for supplying HC, an air supply means for supplying air provided in an exhaust passage between the reduction catalyst outlet and the oxidation catalyst inlet for burning HC, and the oxidation catalyst Heat is exchanged between the circulating water and the air supplied to the vehicle interior, and the first heat exchanger arranged so as to exchange heat between the exhaust gas in the exhaust passage of the outlet and the circulating water. And a second heat exchanger arranged as described above. 2. A reduction catalyst and an oxidation catalyst provided in an exhaust passage of an internal combustion engine, and an exhaust passage between an exhaust port of the internal combustion engine and an inlet of the reduction catalyst for purifying NO _x. An HC supply means for supplying HC, an air supply means for supplying air provided in an exhaust passage between the reduction catalyst outlet and the oxidation catalyst inlet for burning HC, and the oxidation catalyst A vehicle heating device, comprising: a third heat exchanger arranged so as to exchange heat between the exhaust gas in the exhaust flow path at the outlet and the air supplied into the vehicle interior. 3. The structure according to claim 1 or 2, further comprising a control means, and the control means is an amount necessary for purifying NO _x of exhaust gas in an exhaust passage with the reduction catalyst. The air supply means is controlled so as to supply only HC, and further, the air supply means is supplied so as to supply air in an amount necessary for completely burning HC contained in the exhaust gas discharged from the outlet of the reduction catalyst. A heating device for a vehicle, characterized by controlling the. 4. The structure according to claim 3, further comprising a temperature sensor for detecting a water temperature of the circulating water or a temperature of air supplied to a vehicle compartment, and means for setting a required heating capacity required by an occupant. The control means burns HC by the oxidation catalyst from the water temperature or the air temperature and the required heating capacity.
Is calculated, and the HC supply means is controlled so as to supply the HC by an amount obtained by adding the calculated HC amount to the HC amount required for purifying NO _X by the reduction catalyst. Vehicle heating system. 5. The vehicle heating apparatus according to claim 3, wherein the control means calculates a required HC supply amount from the rotation speed of the internal combustion engine and the fuel supply amount to the internal combustion engine. .