US 5,107,804 A · Variable camshaft timing for internal combustion engine

Abstract

A camshaft (426) has a vane (460) secured to an end thereof for non-osciling rotation therewith. The camshaft also carries a sprocket (432) which can rotate with the camshaft but which is oscillatable with respect to the camshaft. The vane has opposed lobes (460a, 460b) which are received in opposed recesses (432a, 432b), respectively, of the sprocket. The recesses have greater circumferential extent than the lobes to permit the vane and sprocket to oscillate with respect to one another, and thereby permit the camshaft to change in phase relative to a crankshaft whose phase relative to the sprocket is fixed by virtue of a chain drive extending therebetween. The camshaft tends to change in reaction to pulses which it experiences during its normal operation, and it is permitted to change only in a given direction, either to advance or retard, by selectively blocking or permitting the flow of hydraulic fluid, preferably engine oil, through the return lines (494, 496) from the recesses by controlling the position of a spool (500) within a valve body (498) of a control valve in response to a signal indicative of an engine operating condition from an engine control unit (508).

Claims22

Dependent claims

In an internal combustion engine having a rotatable crankshaft and a rotatable camshaft, the camshaft being position variable relative to the crankshaft, being subject to torque reversals during the rotation thereof, having a vane with at least one lobe secured to the camshaft for rotation therewith, and having a housing mounted on the camshaft for rotation with the camshaft and for oscillation with respect to the camshaft, the housing having at least one recess receiving the at least one lobe of the vane and permitting oscillation of the at least one lobe within the at least one recess as the housing oscillates with respect to the camshaft, the engine further having means for transmitting rotational movement from the crankshaft to the housing and means for varying the position of the housing relative to the camshaft, the method comprising:

actuating the means for varying the position of the housing relative to the camshaft in reaction to torque reversals in the camshaft.

In an internal combustion engine having a rotatable crankshaft and a rotatable camshaft, the camshaft being position variable relative to the crankshaft and being subject to torque reversals during the operation thereof, the method comprising:

providing the camshaft with a vane having at least one lobe, the vane being rotatable with the camshaft and being non-oscillatable with respect to the camshaft;
providing the camshaft with a housing having at least one recess, the housing being rotatable with the camshaft and being oscillatable with respect to the camshaft, the at least one recess of the housing receiving the at least one lobe of the vane and permitting oscillation of the at least one lobe within the at least one recess as the housing oscillates with respect to the camshaft;
providing means for transmitting rotary movement from the crankshaft to the housing;
providing means for varying the position of the housing relative to the camshaft;
and
actuating the means for varying the position of the housing relative to the camshaft in reaction to torque reversals in the at least one camshaft.

3 more elements

An internal combustion engine comprising:

a crankshaft, said crankshaft being rotatable about an axis;
a camshaft, said camshaft being rotatable about a second axis, said second axis being parallel to said axis, said camshaft being subject to torque reversals during the rotation thereof;
a vane having at least one lobe, said vane being attached to said camshaft, being rotatable with said camshaft and being non-oscillatable with respect to said camshaft;
a housing, said housing being rotatable with said camshaft and being oscillatable with respect to said camshaft, said housing having at least one recess, said at least one recess receiving said at least one lobe, said at least one lobe being oscillatable within said at least one recess;
rotary movement transmitting means for transmitting rotary movement from the crankshaft to the housing;
and
means reactive to torque reversals in the camshaft for varying the position of the housing relative to the camshaft.

4 more elements

An internal combustion engine comprising:

a crankshaft, said crankshaft being rotatable about an axis;
a camshaft, said camshaft being rotatable about a second axis, said second axis is being parallel to said axis, said camshaft being subject to torque reversals during the rotation thereof;
a vane having first and second circumferentially spaced apart lobes, said vane being attached to said camshaft, being rotatable with said camshaft and being non-oscillatable with respect to said camshaft;
a housing, said housing being rotatable with said camshaft and being oscillatable with respect to said camshaft, said housing having first and second circumferentially spaced apart recesses, each of said first and second recesses receiving one of said first and second lobes and permitting oscillating movement of said one of said first and second lobes therein;
rotary movement transmitting means for transmitting rotary movement from the crankshaft to the housing;
and
means reactive to torque reversals in the camshaft for varying the position of the housing relative to the camshaft.

4 more elements

Dependencies are inferred from the claim text.

Variable camshaft timing for internal combustion engine

Life of this patent

Variable camshaft timing for internal combustion engine

Life of this patent

Abstract

Claims22