Variator fault detection system
AssigneeAllison Transmission, Inc.
InventorsCharles F. Long, Darren J. Weber
Life of this patent
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Abstract
A variator fault detection system for a continuously variable transmission is incorporated into a hydraulic control circuit that controls fluid pressure applied to a variator of the continuously variable transmission. The hydraulic control circuit for the variator includes a number of electrically-controlled shift valves and pressure control valves. Sensing devices are multiplexed to these valves to detect a number of different possible fault states relating to the variator shift valves and the variator pressure control valves.
Claims20
A variator control circuit, comprising:
- a plurality of variator control devices in fluid communication with a variator of a continuously variable transmission to selectively deliver hydraulic fluid pressure to the variator, and
- a maximum of two sensing devices configured to detect faults occurring in any one of the plurality of variator control devices.
A variator control circuit comprising:
- a plurality of variator control devices in fluid communication with a variator of a continuously variable transmission, including:
- (i) a first shift valve and a second shift valve, each of the shift valves movable from a first position to a second position axially spaced from the first position;
- (ii) a first trim valve selectively coupled to the first shift valve and a second trim valve selectively coupled to the second shift valve;
- and
- (iii) a first electro-hydraulic actuator coupled to the first shift valve and a second electro-hydraulic actuator coupled to the second shift valve, and
- a plurality of sensing devices configured to detect faults occurring in any one of the plurality of variator control devices, including:
- (i) a first sensor coupled to the first shift valve, and
- (ii) a second sensor coupled to the second shift valve.
A variator control circuit comprising:
- a plurality of variator control devices in fluid communication with a variator of a continuously variable transmission, including:
- (i) a first shift valve in fluid communication with a second shift valve, each of the shift valves in fluid communication with a variator of a continuously variable transmission, movable from a first position to a second position axially spaced from the first position, and having a valve head and a spring pocket,
- (ii) a first trim valve selectively coupled to the first shift valve and a second trim valve selectively coupled to the second shift valve,
- (iii) a first electro-hydraulic actuator coupled to the first shift valve and a second electro-hydraulic actuator coupled to the second shift valve, and
- (iv) a variator fault valve selectively coupled to the first shift valve and selectively coupled to the second shift valve;
- and
- a plurality of sensing devices configured to detect faults occurring in any one of the plurality of variator control devices, including (i) a first sensor coupled to the first shift valve, and (ii) a second sensor coupled to the second shift valve.
Dependencies are inferred from the claim text.