Compressor override control
An engine system incorporating an intake manifold, a compressor, and a controller. The compressor may provide air to the intake manifold and the controller may be connected to the intake manifold and the compressor. The controller may receive a control signal and control air flow from the compressor to the intake manifold based on the received control signal. The controller may control the air flow from the compressor to the intake manifold based on a first equation when a value related to the control signal is on a first side of a threshold and according to a second equation when the value is on a second side of the threshold. The controller may control the air flow between the compressor and intake manifold according to the second equation to prevent the compressor from operating at a surge condition when controlling the air flow according to the first equation.
1. An engine system comprising:
an intake manifold;
a compressor for providing an air flow to the intake manifold; and
an electronic controller connected to the intake manifold and the compressor, the electronic controller is configured to:
control a position of an actuator controlling airflow from the compressor to the intake manifold based on a control signal received according to a first non-zero rate of change of the position of the actuator when a value related to the control signal is on a first side of a threshold;
control the position of the actuator controlling airflow from the compressor to the intake manifold based on the control signal received according to a second non-zero rate of change of the position of the actuator when the value related to the control signal has crossed from the first side of the threshold to a second side of the threshold, the second non-zero rate of change of the position of the actuator is slower than the first non-zero rate of change of the position of the actuator; and
wherein the electronic controller is configured to control the position of the actuator based on the following equation:
∑
h
=
1
H
a
h
(
t
)
d
u
h
(
t
)
d
t
≥
b
(
t
)
-
∑
k
=
H
+
1
K
a
k
(
t
)
d
u
k
(
t
)
d
t
,
where K is a total number of control signals sent to actuators, H is a number of modifiable control signals sent to actuators of the K control signals, t is a unit of time, a h (t) and a k (t) are weighting values, u h (t) and u k (t) are external input values, and b(t) is a limit value.
2. The engine system of claim 1 , wherein the threshold is a surge line on a compressor map of flow rate of the air flow from the compressor to the intake manifold versus a pressure ratio of a pressure at an output of the compressor over a pressure at an input of the compressor.
3. The engine system of claim 1 , wherein the value is a predicted value of a function dependent on a flow rate of the air flow from the compressor to the intake manifold and a pressure ratio of a pressure at an output of the compressor over a pressure at an input of the compressor.
4. The engine system of claim 1 , wherein:
the control signal is a position of an acceleration actuator; and
the value related to the control signal is a function of a change of rate in the position of the acceleration actuator.
5. The engine system of claim 1 , further comprising:
a sensor sensing a compressor speed and providing the compressor speed to the electronic controller as an input;
the value related to the control signal is a function of the compressor speed.
6. The engine system of claim 1 , further comprising:
a sensor sensing a pressure downstream of the compressor; and
the value related to the control signal is a function of the pressure downstream of the compressor.
7. The engine system of claim 1 , further comprising:
a sensor sensing a flow rate of air flow through the compressor; and
the value related to the control signal is a function of the flow rate of air flow through the compressor.
8. The engine system of claim 1 , further comprising:
a sensor sensing an ambient pressure; and
a sensor sensing an ambient temperature; and
the value related to the control signal is a function of one or both of the ambient pressure and the ambient temperature.
9. The engine system of claim 1 , wherein the electronic controller is configured to determine the value from a look up table calculated when an engine of the engine system is off-line based on inputs received from sensors when the engine is on-line.
10. The engine system of claim 1 , wherein the electronic controller is configured to:
output the actuator modifiable control signals to the actuators of an engine of the engine system to control the air flow from the compressor to the intake manifold; and
limit adjustment of the modifiable actuator control signals such that the value related to the control signal does not cross from the first side of the threshold to the second side of the threshold.
11. The engine system of claim 10 , wherein the electronic controller is configured to output the modifiable actuator control signals to one or both of a throttle valve actuator and a waste gate actuator when controlling airflow from the compressor to the intake manifold based on the control signal received according to the second non-zero rate of change of the position of the actuator.
12. The engine system of claim 10 , wherein the electronic controller is configured to adjust the modifiable actuator control signals in a sequential manner when the electronic controller is configured to control airflow from the compressor to the intake manifold based on the control signal received according to the second non-zero rate of change of the position of the actuator.
13. The engine system of claim 1 , further comprising:
a throttle valve configured to modulate an amount of air flow from the compressor to the intake manifold; and
wherein for a same inputted control signal, the electronic controller is configured to control a position of the throttle valve differently when controlling air flow from the compressor to the intake manifold according to the second non-zero rate of change of the position of the actuator than when controlling air flow from the compressor to the intake manifold according to the first non-zero rate of change of the position of the actuator.