US2007028874A1PendingUtilityA1
Mapping temperature compensation limits for PWM control of VCT phasers
Est. expiryAug 2, 2025(expired)· nominal 20-yr term from priority
Inventors:Roger T. Simpson
F01L 2001/34426F01L 2800/00F01L 1/022F01L 1/3442F01L 2001/3443F01L 2800/01F01L 1/024F01L 2820/01F01L 1/026
40
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Claims
Abstract
A variable cam timing (VCT) phaser system including a phaser with an actuator in which the max duty cycle is altered to maintain a constant current in the system based on at least one engine parameter.
Claims
exact text as granted — not AI-modified1 . A method of maintaining a constant actuation rate in an engine comprising the steps of:
a) setting a maximum actuation rate and sending the rate to a controller; b) determining at least one engine control parameter and sending the at least one engine control parameter to the controller; c) using the at least one engine control parameter to determine a new duty cycle in the controller; d) comparing the new duty cycle to a current duty cycle in the controller; and e) adjusting and outputting the new duty cycle from the controller to an actuator.
2 . The method of claim 1 , wherein the at least one engine control parameter is voltage.
3 . The method of claim 1 , wherein the at least one engine control parameter is temperature.
4 . The method of claim 3 , wherein the temperature is from a pressurized source of fluid, a coolant system, engine block, engine compartment, radiator, or a cooling system.
5 . The method of claim 1 , wherein the at least one engine control parameters are temperature and voltage.
6 . The method of claim 1 , wherein the actuator is a pulse width modulated solenoid.
7 . The method of claim 1 , wherein determining the new duty cycle comprises the steps of selecting a temperature limit curve.
8 . The method of claim 1 , wherein determining the new duty cycle comprises the step of selecting a voltage curve.
9 . The method of claim 1 , wherein determining the new duty cycle comprises the steps of selecting a voltage curve and selecting a temperature limit curve.
10 . The method of claim 1 , wherein the new duty cycle is a maximum duty cycle and is determined by equation:
[
1
V
0
+
Δ
V
[
R
0
*
α
(
Δ
T
)
]
+
R
0
]
*
100
=
Max
DC
,
where V 0 is an initial voltage, R 0 is an initial resistance, ΔV is a change in voltage,
ΔT is a change in temperature, and α is a temperature coefficient of resistance.
11 . A method of maintaining a constant actuation rate in an internal combustion engine comprising the steps of:
a) setting a maximum actuation rate of a variable cam timing system and sending the rate to a controller; b) determining at least one engine control parameter and sending the at least one engine control parameter to the controller; c) using the at least one engine control parameter to determine a new maximum duty cycle in the controller; d) comparing the new maximum duty cycle to a current duty cycle in the controller; and e) adjusting and outputting the new maximum duty cycle from the controller to an actuator, such that the actuator positions a control valve of a variable cam timing phaser of the variable cam timing system, altering the phase of the variable cam timing system.
12 . The method of claim 11 , wherein the at least one engine control parameter is voltage.
13 . The method of claim 11 , wherein the at least one engine control parameter is temperature.
14 . The method of claim 13 , wherein the temperature is from a pressurized source of fluid, a coolant system, engine block, engine compartment, radiator, or a cooling system.
15 . The method of claim 11 , wherein the at least one engine control parameters are temperature and voltage.
16 . The method of claim 11 , wherein the actuator is a pulse width modulated solenoid.
17 . The method of claim 11 , wherein determining the new maximum duty cycle comprises the step of selecting a temperature limit curve.
18 . The method of claim 11 , wherein determining the new maximum duty cycle comprises the step of selecting a voltage curve.
19 . The method of claim 11 , wherein determining the new maximum duty cycle comprises the steps of selecting a voltage curve and selecting a temperature limit curve.
20 . The method of claim 11 , wherein the new maximum duty cycle is determined by equation:
[
1
V
0
+
Δ
V
[
R
0
*
α
(
Δ
T
)
]
+
R
0
]
*
100
=
Max
DC
,
where V 0 is an initial voltage, R 0 is an initial resistance, ΔV is a change in voltage, ΔT is a change in temperature, and α is a temperature coefficient of resistance.
21 . The method of claim 11 , wherein the variable cam timing phaser comprises:
a housing with an outer circumference for receiving drive force; a rotor for connection to a camshaft coaxially located within the housing having at least one vane, wherein the housing and the rotor define at least one chambers, separated by the vane into an advance chamber and a retard chamber, the vane being capable of rotation to shift relative angular position of the housing and the rotor; and a control valve coupled to the actuator and in connection with the advance chamber and the retard chamber for directing fluid flow to shift the relative angular position of the rotor relative to the housing.
22 . The method of claim 21 , wherein the control valve allows fluid to flow between the advance chamber and the retard chamber.
23 . The method of claim 22 , further comprising at least one check valve between the advance chamber and the retard chamber and the control valve for blocking reverse fluid flow.
24 . The method of claim 21 , further comprising a passage in fluid communication with a pressurized fluid source.
25 . The method of claim 24 , further comprising a check valve in the passage.
26 . A variable cam timing system for an internal combustion engine comprising:
a phaser having:
a housing with an outer circumference for receiving drive force;
a rotor for connection to a camshaft coaxially located within the housing having at least one vane, wherein the housing and the rotor define at least one chambers, separated by the vane into an advance chamber and a retard chamber, the vane being capable of rotation to shift relative angular position of the housing and the rotor; and
a control valve in connection with the advance chamber and the retard chamber for directing fluid flow to shift the relative angular position of the rotor relative to the housing;
a controller receiving input from at least one engine parameter, and an engine control unit and outputting a new duty cycle based on the at least one engine parameter and the engine control unit to an actuator coupled to the control valve for positioning the control valve, such that the angular position of the housing relative to the rotor of variable cam timing phaser of the variable cam timing system is altered.
27 . The variable cam timing system of claim 26 , wherein the control valve allows fluid to flow between the advance chamber and the retard chamber.
28 . The variable cam timing system of claim 27 , further comprising at least one check valve between the advance chamber and the retard chamber and the control valve for blocking reverse fluid flow.
29 . The variable cam timing system of claim 26 , further comprising a passage in fluid communication with a pressurized fluid source.
30 . The variable cam timing system of claim 29 , further comprising a check valve in the passage.
31 . The variable cam timing system of claim 26 , wherein the engine control unit provides the angular phase position between the housing and the rotor.
32 . The variable cam timing system of claim 26 , wherein a method of determining the new duty cycle comprises the steps of:
a) setting a maximum actuation rate of a variable cam timing system from the engine control unit and sending the rate to a controller; b) determining the at least one engine control parameter and sending the at least one engine control parameter to the controller; c) using the at least one engine control parameter to determine the new maximum duty cycle in the controller; d) comparing the new maximum duty cycle to a current duty cycle in the controller; and e) adjusting and outputting the new maximum duty cycle from the controller to an actuator, such that the actuator positions a control valve of a variable cam timing phaser of the variable cam timing system, altering the phase of the variable cam timing system.
33 . The variable cam timing system of claim 32 , wherein the at least one engine control parameter is voltage.
34 . The variable cam timing system of claim 32 , wherein the at least one engine control parameter is temperature.
35 . The variable cam timing system of claim 34 , wherein the temperature is from a pressurized source of fluid, a coolant system, engine block, engine compartment, radiator, or a cooling system.
36 . The variable cam timing system of claim 32 , wherein the at least one engine control parameters are temperature and voltage.
37 . The variable cam timing system of claim 32 , wherein the actuator is a pulse width modulated solenoid.
38 . The variable cam timing system of claim 32 , wherein determining the new maximum duty cycle comprises the step of selecting a temperature limit curve.
39 . The variable cam timing system of claim 32 , wherein determining the new maximum duty cycle comprises the step of selecting a voltage curve.
40 . The variable cam timing system of claim 32 , wherein determining the new maximum duty cycle comprises the steps of selecting a voltage curve and selecting a temperature limit curve.
41 . The variable cam timing system of claim 32 , wherein the new maximum duty cycle is determined by equation:
[
1
V
0
+
Δ
V
[
R
0
*
α
(
Δ
T
)
]
+
R
0
]
*
100
=
Max
DC
,
where V 0 is an initial voltage, R 0 is an initial resistance, ΔV is a change in voltage, ΔT is a change in temperature, and a is a temperature coefficient of resistance.
42 . The variable cam timing system of claim 32 , wherein the controller is part of the engine control unit.Join the waitlist — get patent alerts
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