Internal combustion engine with valve rest mechanisms

Details Internal combustion engine with valve rest mechanisms Internal combustion engine with valve rest mechanisms

1999-11-04

2001-05-22

Lo, Weilun (Department: 3748)

Internal-combustion engines

Poppet valve operating mechanism

With means for varying timing

C123S090270, C123S308000, C123S315000, C060S289000, C060S304000

Reexamination Certificate

active

06234124

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an internal combustion engine provided with an exhaust secondary air introduction assembly and valve rest mechanisms.
2. Background Art
Guiding of exhaust secondary air into an exhaust path is a well known way of oxidizing unburned components of HC and CO in exhaust gas expelled from a combustion chamber of an internal combustion engine. An air suction-type exhaust secondary introduction assembly employing a reed valve is a well known assembly for introducing exhaust secondary air.
Internal combustion engines exist having valve rest mechanisms for resting the opening and closing operation of some of the inlet valves of a plurality of inlet valves, or resting the opening and closing of some of the exhaust valves of a plurality of exhaust valves, as in Japanese Patent Laid-open Publication No. Hei. 10-184.327. This operation is carried out when the engine is running at a low number of revolutions, or under a low load, so that only a small amount of air is taken in.
There are, however, problems associated with exhaust secondary air introduction assemblies for internal combustion engines having valve rest mechanisms. When one or more of the exhaust valves are stopped, the flow of exhaust gases at the exhaust port is deflected so that exhaust gas is not expelled from the exhaust outlets provided for the exhaust valves that are stopped. It is, however, necessary to maintain a spacing using the position of the exhaust secondary air introduction inlet of the exhaust port for the deflected flow so that there is sufficient mixing of the exhaust gas and the exhaust secondary air by the time the exhaust gas reaches an exhaust purification assembly.
The air suction-type exhaust secondary air introduction assembly also has to ensure, with the position of the exhaust secondary air introduction opening of the exhaust port, that the pulsation pressure of the exhaust gas operates on the exhaust secondary air introduction opening when one or more exhaust valves are stopped.
SUMMARY OF THE INVENTION
In order to overcome the aforementioned disadvantages, the present invention provides an internal combustion engine with valve rest mechanisms where exhaust secondary air is brought to an exhaust port so as to be introduced in a stable manner, regardless of the resting and opening and closing operation of one or more exhaust valves. This is done by ensuring that the amount of exhaust secondary air required for purification is introduced at the exhaust port when one or more exhaust valves are stopped.
In addition to the above, the present invention provides an internal combustion engine with a valve rest mechanism and a plurality of cylinders in which the structure for introducing exhaust secondary air is compact.
An internal combustion engine is provided with valve rest mechanisms for resting a valve opening and closing operation of some of a plurality of exhaust valves provided per cylinder in response to a running state of the engine. The exhaust secondary air introduction opening is provided at an exhaust port in the vicinity of exhaust valves not equipped with valve rest mechanisms.
Exhaust secondary air introduction openings are provided at an exhaust port in the vicinity of exhaust valves that constantly open and close and which are not equipped with valve rest mechanisms. An amount of exhaust secondary air necessary for air purification can therefore be introduced even when the exhaust valves equipped with the valve rest mechanisms are stopped. Exhaust secondary air can be introduced at the exhaust port in a stable manner regardless of the resting and opening and closing operation of some of the exhaust valves. The rate of purification of exhaust gas occurring at an exhaust purification assembly is therefore increased.
The internal combustion engine has a plurality of cylinders and valve rest mechanisms for resting a valve opening and closing operation of some of a plurality of exhaust valves provided per cylinder. The resting is done in response to the running state of the engine. Exhaust valves not equipped with valve rest mechanisms are provided at exhaust outlets on neighboring sides of neighboring pairs of cylinders, and an exhaust secondary air introduction opening is provided at an exhaust port in the vicinity of exhaust valves not equipped with valve rest mechanisms.
Exhaust valves not equipped with valve rest mechanisms are provided at mutually neighboring exhaust openings at neighboring pairs of cylinders, and an exhaust secondary air introduction opening is provided at the exhaust port in the vicinity of these exhaust valves. The exhaust secondary air can therefore be introduced in a stable manner to the exhaust port. The purification rate for the exhaust gas occurring in the exhaust purification is improved. Also, the points at which the exhaust secondary air paths reach the exhaust secondary air introduction opening connect together and can be arranged collectively, resulting in a more compact structure.
A pair of housings for housing valves for controlling an amount of air introduced at each exhaust secondary air introduction opening are provided which are connected at an upper surface of a cylinder head cover. A single reed valve cap covers the pair of housings, so that it is not necessary to mount separate reed valve caps on the respective housings. The number of assembly steps and parts can be therefore reduced.
One or more of a plurality of exhaust valves provided for each pair of cylinders are equipped with valve rest mechanisms for resting the opening and closing of valves according to the running state of the engine. Exhaust valves equipped with valve rest mechanisms are provided at inlets on neighboring sides of pairs of cylinders. Therefore, when the internal combustion engine runs at low speed or with a low load so that the intake valves equipped with valve rest mechanisms and the exhaust valves are stopped, air that flows in from just the inlets provided at the intake valves that are not provided with valve rest mechanisms forms a vortex current (for example, a swirl) within the ignition chamber. Combustibility is therefore improved and improvements in fuel consumption and emissions are obtained.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.


REFERENCES:
patent: 4221197 (1980-09-01), Kuroda et al.
patent: 4395876 (1983-08-01), Marsee et al.
patent: 5361734 (1994-11-01), Shirai
patent: 5758612 (1998-06-01), Tsuzuku et al.
patent: 5832725 (1998-11-01), Sim
patent: 10-184327 (1998-07-01), None

Affiliated with

Also associated with

Rating

Internal combustion engine with valve rest mechanisms does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Internal combustion engine with valve rest mechanisms, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Internal combustion engine with valve rest mechanisms will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2503854