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US 8,079,210 B2Granted
Engine
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsNoboru Nowatari, Hideo Fujita
Life of this patent
Estimating the term…
Abstract
An engine can include a first catalyst disposed in a first exhaust passage, a second catalyst disposed in a second exhaust passage to be located upstream of the first catalyst, a variable valve operating mechanism configured to make lifting amounts of a first and second exhaust valves variable between approximate zero and maximum, and a lifting amount control unit for controlling the lifting amounts of the first and second exhaust valves with the variable valve operating mechanism such that an exhaust gas amount passing through the second exhaust passage is larger than that passing through the first exhaust passage.
Claims13
An engine comprising:
- a first exhaust valve and a second exhaust valve;
- a first exhaust passage and a second exhaust passages opened and closed by the first and second exhaust valves, respectively;
- a first catalyst disposed in the first exhaust passage;
- a second catalyst disposed in the second exhaust passage so as to be located upstream of the first catalyst;
- a variable valve operating mechanism configured to adjust lifting amounts of the first and the second exhaust valves between approximately zero and a maximum lifting amount;
- and
- a lifting amount control unit configured to control lifting amounts of the first and the second exhaust valves with the variable valve operating mechanism such that an exhaust gas amount passing through the second exhaust passage is larger than an exhaust gas amount passing through the first exhaust passage at least during start-up of the engine, and such that the exhaust gas amount passing through the first exhaust passage is larger than the exhaust gas amount passing through the second exhaust passage at least in a range of high-speed rotation and large-load operation of the engine after completion of a warm-up operation of the engine;
- wherein
- the second catalyst is provided in a cylinder head and is disposed within a second exhaust port which defines a portion of the second exhaust passage;
- and
- the first exhaust valve includes two first exhaust valves disposed side-by-side in a camshaft direction, and the second exhaust valve is disposed between the two first exhaust valves.
8 more elements
An engine comprising:
- a cylinder head including at least one combustion chamber surface;
- first, second, and third exhaust valve seats opening in the combustion chamber surface, the third exhaust valve seat being smaller than the first and second exhaust valve seats;
- first, second, and third exhaust valves engaged with the first, second, and third exhaust valve seats;
- first, second, and third exhaust passages extending from the first, second, and third exhaust valve seats, respectively, toward an outer surface of the cylinder head, the third exhaust passage defining an exhaust port opening at the outer surface of the cylinder head, separate from the first and second exhaust passages;
- a first catalyst device including an upstream end communicating with the first and second exhaust passages;
- a second catalyst device including an upstream end communicating with the third exhaust passage but not the first or second exhaust passages;
- a variable valve operating mechanism configured to adjust lifting amounts of the first, second, and third exhaust valves between approximately zero and a maximum lifting amount;
- and
- a lifting amount control unit configured to control lifting amounts of the first, second, and third exhaust valves with the variable valve operating mechanism such that an exhaust gas amount passing through the third exhaust passage is larger than an exhaust gas amount passing through the first and second exhaust passages, at least during start-up of the engine, and such that the exhaust gas amount passing through the first and second exhaust passages is larger than the exhaust gas amount passing through the third exhaust passage at least in a range of high-speed rotation and large-load operation of the engine after completion of a warm-up operation of the engine.
6 more elements
Dependencies are inferred from the claim text.