Vehicular exhaust device

A vehicular exhaust device is disclosed. The vehicular exhaust device includes an exhaust pipe, which is connected at one end to an exhaust manifold of a cylinder and at the other end to a catalytic converter. In particular, an intermediate portion of the exhaust pipe is in contact with the side surface of the catalytic converter so as to heat the catalytic converter by heat of the exhaust pipe.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2015-0155812, filed on Nov. 6, 2015, which is incorporated herein by reference in its entirety.

FIELD

The present disclosure relates to a vehicular exhaust device.

BACKGROUND

A typical vehicular engine, which is an internal-combustion engine, is provided with an exhaust system for the discharge of exhaust gas generated by burning fuel in a cylinder.

A cylinder head is provided therein with an exhaust port so as to allow exhaust gas in the cylinder to be discharged through the exhaust port. The exhaust gas discharged from the exhaust port is supplied to a catalytic converter through an exhaust manifold and an exhaust pipe.

Recently, in order to reduce exhaust interference, an exhaust pipe is elongated so as to have a sufficient length. However, this construction increases the light-off time (LOT), which is taken to reach the activation temperature of a catalyst in order to purify exhaust gas when an engine is started up at a low temperature, thereby degrading the capability of satisfying the exhaust gas emission standard. Furthermore, a measure of increasing the content of noble metals contained in the catalytic converter in order to improve the capability causes excessive increase in manufacturing costs.

SUMMARY

The present disclosure provides a vehicular exhaust device in which an exhaust pipe partially contacts a catalytic converter so as to reduce the time taken to reach the activation temperature to thus increase purification efficiency.

The present disclosure provides a vehicular exhaust device including an exhaust pipe, which is connected at one end thereof to an exhaust manifold of a cylinder and at the other end thereof to a catalytic converter, and an intermediate portion of the exhaust pipe is in contact with the side surface of the catalytic converter.

The intermediate portion of the exhaust pipe may be curved so as to surround the side surface of the catalytic converter, which has a cylindrical shape, in the state of being arranged around the side surface thereof.

The cylinder block may include a plurality of cylinders.

The number of exhaust manifolds may be smaller than the number of cylinders, and first ends of the exhaust manifolds may be branched so as to be respectively connected to the plurality of cylinders such that the cylinder connected to one of the exhaust manifolds is different from the cylinders connected to the remaining exhaust manifolds, wherein the exhaust pipe includes a plurality of exhaust pipes and the exhaust manifold includes a plurality of exhaust manifolds such that the number of exhaust pipes is the same as the number of exhaust manifolds, and first ends of the exhaust pipes are connected to second ends of different exhaust manifolds and second ends of the exhaust pipes are combined with each other, the combined end being connected to a first end of the catalytic converter.

First ends of the exhaust manifolds may be branched and extend by the same length, and the branched ends of the exhaust manifolds may be connected to respective ones among the plurality of cylinders.

The exhaust manifold may be integrally formed in the cylinder head.

The exhaust manifold may be coupled to a portion of the cylinder head.

The exhaust pipe may be integrally formed with the catalytic converter.

According to the vehicular exhaust device, which is constructed as described above, the light-off time (LOT), which is taken to activate a catalytic converter when a vehicle is started up at a low temperature, is decreased, thereby increasing exhaust gas purification efficiency.

Furthermore, since there is no need to increase the content of noble metal contained in a catalytic converter in order to increase the purification efficiency, it is possible to remarkably reduce manufacturing costs.

DETAILED DESCRIPTION

FIG. 1is a view showing the vehicular exhaust device according to one form of the present disclosure. Referring toFIG. 1, the vehicular exhaust device may include an exhaust pipe20, which is connected at one end thereof to an exhaust manifold10and at the other end thereof to a catalytic converter30. The exhaust pipe20is also in contact at an intermediate portion40thereof with the side surface of the catalytic converter30.

A cylinder block5is provided therein with a cylinder, which provides space for burning fuel, and a cylinder head1connected with the cylinder block5is provided therein with the exhaust manifold10, which serves as a channel through which gas, resulting from burning of the fuel in the cylinder3, is discharged to the outside. The exhaust manifold10is connected at a first end thereof to the cylinder3and at a second end thereof to the exhaust pipe20.

The exhaust pipe20is connected at one end thereof to the exhaust manifold10and at the other end thereof to the catalytic converter30for purifying exhaust gas. In other words, the catalytic converter30receives exhaust gas which is discharged through the exhaust manifold10and the exhaust pipe20.

The catalytic converter30serves to purify hydrocarbons, which are the undesirable compound in exhaust gas. The purification of hydrocarbon is efficiently implemented at a temperature of about 200 to 350° C. However, if the catalytic converter30is not in the state of being sufficiently heated and activated because a vehicle is started up at a low temperature, unburned hydrocarbon may be discharged into the atmosphere without purification by the catalytic converter30, thereby it may not satisfy exhaust gas emission standards.

Accordingly, the present disclosure in one form provides an intermediate portion40of the exhaust pipe20that is in contact with the side surface of the catalytic converter30so as to reduce the light-off time (LOT) which is the time taken by the catalytic converter30to reach the activation temperature. In another form, the intermediate portion40of the exhaust pipe20may be disposed close to the side surface of the catalytic converter30so that the catalytic converter30receives heat generated from the exhaust pipe20. In other words, since high-temperature exhaust gas discharged from the cylinder3indirectly heats the catalytic converter30while the exhaust gas passes through the exhaust pipe20. As a result, it is possible to reduce the time taken to increase the temperature of the catalytic converter30to the activation temperature.

With these or similar arrangements, the LOT desired to activate the catalytic converter30may be shorten even when a vehicle is started, and it is possible to increase the exhaust gas purification efficiency. Advantageously, since there is no need to increase the content of noble metal contained in the catalytic converter30in order to increase the purification efficiency, it is possible to remarkably reduce manufacturing costs.

In one form, the intermediate portion40of the exhaust pipe20is curved so as to surround the side surface of the catalytic converter30, which has a cylindrical shape, in the state of contacting the side surface thereof.

In other words, the exhaust pipe20extends from the exhaust manifold10so as to surround the outer surface of the catalytic converter30, whereby the contact area between the exhaust pipe20and the catalytic converter30is increased, thereby further increasing the temperature of the catalytic converter30. Here, the contact surface between the catalytic converter30and the exhaust pipe20may be a curved surface.

If the catalytic converter30has a rectangular section, the intermediate portion40of the exhaust pipe20may be bent at a right angle so as to closely surround the catalytic converter30. In other words, the exhaust pipe20may have a complimentary shape to maintain the contact or reduce a gap between the exhaust pipe20and the catalytic converter30.

The number of the exhaust manifolds10may be fewer than the number of cylinders3. With this arrangement, each of the exhaust manifolds10may be branched at a first end thereof and is connected to a corresponding cylinder3such one or more cylinders3may be connected to one exhaust manifold10. However, the cylinder(s) connected to one of the exhaust manifolds10is not connected to other remaining exhaust manifolds10. Meanwhile, the number of the exhaust pipes20may be same as the number of the exhaust manifolds10, and thus each of the exhaust pipes20is connected at first ends thereof to the second end of the corresponding exhaust manifold10, and the exhaust pipes20are combined with each other at second ends thereof. The combined end of the exhaust pipes20is connected to the first end of the catalytic converter30.

FIG. 2is a perspective view showing the vehicular exhaust device according to one form of the present disclosure.FIG. 3is a side view showing the vehicular exhaust device. Referring toFIGS. 2 and 3, in the case where there are four cylinders3and two exhaust manifolds10, one of the two exhaust manifolds10may be connected to the first and fourth cylinders and the other exhaust manifold10may be connected to the second and third cylinders. In other words, cylinders3that do not consecutively execute expansion strokes are connected to each other, thereby reducing exhaust interference.

In the case where six cylinders3and two or three exhaust manifolds10are provided, each of the exhaust manifolds10is connected to cylinders3that do not consecutively execute expansion strokes, thereby inhibiting or preventing exhaust interference. Here, the numbers of cylinders3and exhaust manifolds10are suggested merely for illustrative purpose, and may be changed depending on a designer or a vehicle.

Accordingly, since there is no need to provide a number of manifolds10as many as the number of cylinders3, it is possible to provide a compact package including the exhaust device, without an excessive number of exhaust manifolds10.

The exhaust manifolds10may be branched at the first ends and may extend by the same length, and the branched ends may be connected to corresponding cylinders3. In other words, one exhaust manifold10may diverge into several branches so that one exhaust manifold10may be connected several cylinders. Specifically, the pressures of exhaust gas discharged from respective cylinders3become equal to each other when the branched ends of the exhaust manifolds10extend by the same length. The length may be measured from the point at which the manifolds10are connected to the exhaust pipe20to the point at which the branched ends of the exhaust manifolds10are connected to the respective cylinders. Therefore, the branched ends of the exhaust manifolds10extend by the same length with respect to the midpoint of the cylinders3, thereby inhibiting or preventing the occurrence of exhaust interference in the exhaust manifolds10.

The exhaust manifolds10may be configured to be coupled to one end of the cylinder head1, as shown inFIGS. 2 and 3, or may be configured to be integrally formed in the cylinder head1.

FIG. 4is a perspective view showing a vehicular exhaust device according to another form of the present disclosure. Referring toFIG. 4, it will be noted that an exhaust manifold10is provided in the cylinder head. Consequently, the construction of the package including the exhaust device may be simplified, and the volume thereof may be reduced.

The exhaust pipes20may be integrally formed with the catalytic converter30. Specifically, although the exhaust pipes20may be coupled to the catalytic converter30by means of bolts, the exhaust pipes20may be integrally formed with the catalytic converter30in order to reduce the outflow of exhaust gas and the volume of the device.

According to the present disclosure, the light-off time (LOT), which is taken to activate a catalytic converter when a vehicle is started up at a low temperature, is reduced, thereby increasing exhaust gas purification efficiency.

Furthermore, since there is no need to increase the content of noble metal contained in a catalytic converter in order to increase the purification efficiency, it is possible to remarkably reduce manufacturing costs.