Claims
- 1. A variable timing system in combination with an internal combustion engine having an engine crankshaft or moveable member, an exhaust camshaft mounted for rotation and extending from the engine, said exhaust camshaft having at least one exhaust cam for controlling the opening and closing of at least one exhaust valve, and an intake camshaft mounted for rotation on the engine, said intake camshaft having at least one intake cam for controlling the opening and closing of at least one intake valve, said system comprising:
- a first pulley wheel means fixedly attached to one end of each of the exhaust camshaft and the crankshaft of the engine;
- a first belt means for interconnecting said first pulley wheel means for transferring rotational drive from the crankshaft to the exhaust camshaft;
- a second pulley wheel means fixedly attached to each of the exhaust camshaft and one end of the intake camshaft at opposite end of the engine;
- a second belt means for interconnecting said second pulley wheel means for transferring rotational drive from the crankshaft via the exhaust camshaft to the intake camshaft;
- idler arm means including a pivoting arm, a cam follower means and an idler wheel in operative contact with a portion of said second belt means;
- positioning cam means operatively coupled to said cam follower means of said idler arm means, for relatively rotating said second pulley wheel means attached to said one end of the intake camshaft with said second pulley wheel means attached to said opposite end of the exhaust camshaft;
- a control means responsive to various engine operating parameters for generating motor control signals; and
- motor means responsive to said motor control signals and operatively coupled to rotate said positioning cams means for positioning said idler arm means for changing the relative rotational position between the input camshaft and the exhaust camshaft.
- 2. A variable camshaft timing system for an internal combustion engine according to claim 1 wherein said control means includes an electronic control unit having a plurality of sensor means each responsive to one of a plurality of engine operating parameters and a look-up means responsive to two of said engine operating parameters for generating a desired position electrical signal indicating the relative rotational position of said intake camshaft and said exhaust camshaft and generating said motor control signals in response thereto.
- 3. A variable camshaft timing system for an internal combustion engine according to claim 1 wherein said belt means is a chain means.
- 4. A variable camshaft timing system for an internal combustion engine according to claim 1 additionally including means for sensing the present rotational position of said intake camshaft and generating a present position electrical signal; and means for comparing said present position electrical signal and said desired position electrical signal for deriving an error signal indicating the direction and angular rotation of said positioning cam means.
- 5. A variable timing system in combination with a "v" type internal combustion engine having an engine crankshaft or moveable member, an exhaust camshaft mounted for rotation in each arm of the "V", each of the exhaust camshafts having at least one exhaust cam for controlling the opening and closing of at least one exhaust valve, and an intake camshaft mounted for rotation in each arm of the "V", each of the intake camshafts having at least one intake cam for controlling the opening and closing of at least one intake valve, said system comprising:
- pulley wheel means mounted on each of the exhaust camshafts and intake camshafts;
- at least two multiple pulley wheel means one mounted on the crankshaft and the other coupled to the engine for rotation and in line with said multiple pulley wheel means on the crankshaft;
- belt means interconnecting each one of said pulley wheel means with another of said pulley wheel means;
- at least two idler wheels in operative contact with said belt means interconnecting said multiple pulley wheel means coupled to the engine for rotation and said pulley wheel means mounted on the crankshaft;
- lever means pivotally mounted for supporting said idler wheels, said lever means having a caming surface,
- positioning cam means in operative contact with said caming surface for pivoting said lever means for rotating the intake camshaft relative to the exhaust camshaft;
- means sensing the angular position of one of the intake camshafts; and
- control means responsive to said means sensing the angular position of one of the intake camshafts for positioning said positioning cam means.
- 6. A variable timing system according to claim wherein said belt means comprises five chains.
- 7. A variable timing system according to wherein said multiple pulley wheel means includes a double pulley means mounted at one end of the crankshaft and in line with said pulley wheel means mounted on the exhaust camshafts at one end of the engine, a single pulley wheel means mounted at the other end of the crankshaft and a triple pulley means coupled to the engine for rotation and in line with said single pulley wheel means on the crankshaft.
- 8. A variable timing system in combination with an internal combustion engine having an engine crankshaft or moveable member, an exhaust camshaft mounted for rotation and extending from the engine, said exhaust camshaft having at least one exhaust cam for controlling the opening and closing of at least one exhaust valve, and an intake camshaft mounted for rotation on the engine, said intake camshaft having at least one intake cam for controlling the opening and closing of at least one intake valve, said system comprising:
- pulley system means attached to one end of each of the crankshaft, exhaust camshaft and intake camshaft, said pulley system means comprising multiple pulley wheel means on at least one of the crankshaft and exhaust camshaft;
- belt means interconnecting said pulley system means;
- at least two idler wheels in operative contact with said belt means around said pulley system means on the intake camshaft;
- lever means pivotally mounted for supporting said idler wheels, said lever means having a caming surface;
- positioning cam means in operative contact with said caming surface for pivoting said lever means for rotating the intake camshaft relative to the exhaust camshaft;
- means sensing the angular position of the intake camshaft;
- control means responsive to said means sensing the angular position of the intake camshaft for positioning said positioning cam means; and
- wherein said pulley system means on the exhaust camshaft is located at both ends of the exhaust camshaft and the pulley system means on the intake camshaft is located at the opposite end of the engine as the pulley system means on the crankshaft.
Parent Case Info
This application is a continuation-in-part of U.S. Ser. No. 181,867 filed Apr. 15, 1988, which is a continuation of Ser. No. 017,670 filed Feb. 24, 1987 now U.S. Pat. No. 4,744,338 issued May 17, 1988.
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
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166705 |
Aug 1985 |
JPX |
Continuations (1)
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Number |
Date |
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Parent |
17670 |
Feb 1987 |
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Continuation in Parts (1)
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Number |
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181867 |
Apr 1988 |
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