Method for controlling vehicle emissions
View Patent ↗A method and system is provided for determining non-sensed vehicle operating parameters of a vehicle system. The method and system further provide for determining an engine air mass flow rate using the non-sensed vehicle operating parameters. A plurality of vehicle operating set-points may be determined using the non-sensed vehicle system operating parameters and the non-sensed engine air mass flow rate. A controller may use the vehicle operating set-points in order to control emissions of the vehicle system.
1. A method for controlling emissions of a vehicle system, the method comprising:
determining a plurality of non-sensed vehicle operating parameters; the said plurality of non-sensed vehicle operating parameters includes a non-sensed air intake mass flow rate, the non-sensed air intake mass flow rate being determined using a volumetric efficiency ratio, a vehicle engine speed, a sensed intake manifold pressure, a displacement volume, and a sensed intake manifold temperature;
determining an engine air mass flow rate of the vehicle system using the non-sensed vehicle operating parameters; and
determining vehicle operating set-points for use in controlling emissions of the vehicle system, the vehicle operating set-points being determined using the non-sensed vehicle operating parameters and the determined engine air mass flow rate.
2. The method according to claim 1 , further comprising determining at least a portion of the non-sensed vehicle operating parameters from a number of sensed vehicle operating parameters.
3. The method according to claim 1 , wherein the non-sensed air intake mass flow rate is determined using the following relationship:
M
intake
=
V
disp
RPM
engine
*
I
M
P
120
*
R
gas
*
I
M
T
η
vol
wherein: M intake is the non-sensed intake mass flow rate, V disp is a displacement volume of the vehicle system, RPM engine is the sensed vehicle engine speed, IMP is the sensed intake manifold pressure, R gas is a gas constant, IMT is the sensed intake manifold temperature, and N vol is the volumetric efficiency ratio.
4. The method according to claim 3 , wherein the volumetric efficiency is determined using the following relationship:
η vol =α(RPM engine ,PR engine )η vol — map (RPM engine ,ρ intake )
wherein: α is a function determined using the vehicle engine speed and an engine pressure ratio; and N vol — map is a function determined using the vehicle engine speed and an engine intake density.
5. The method according to claim 1 , wherein the plurality of non-sensed vehicle operating parameters includes a non-sensed EGR mass flow rate, the non-sensed EGR mass flow rate being determined using a non-sensed turbine inlet temperature, a non-sensed turbine inlet pressure, an EGR valve discharge coefficient, and an engine pressure differential.
6. The method according to claim 5 , wherein the non-sensed EGR mass flow rate is determined using the following relationship:
M
EGR
2
*
T
T
I
T
P
I
*
Disc
C
2
=
C
1
*
Δ
P
+
C
2
wherein: M EGR is the non-sensed EGR mass flow rate, TTI is the non-sensed turbine inlet temperature, TPI is the non-sensed turbine inlet pressure, DisC is an EGR valve discharge coefficient, C 1 is a constant value dependent upon the vehicle system, C 2 is a function of a sensed vehicle engine speed and a vehicle engine load, and ΔP is the engine pressure differential.
7. The method according to claim 1 , wherein the plurality of non-sensed vehicle operating parameters includes a non-sensed turbine mass flow rate, the non-sensed turbine mass flow rate being determined using a reduced turbine mass flow rate, a non-sensed turbine inlet temperature, and a non-sensed turbine inlet pressure.
8. The method according to claim 7 , wherein the non-sensed turbine mass flow rate is determined using the following relationship:
M
turbine
=
M
turbine_reduced
*
T
P
I
T
T
I
wherein: M turbine is the non-sensed turbine mass flow rate, M turbine — reduced is the reduced turbine mass flow rate, TTI is the non-sensed turbine inlet temperature, and TPI is the non-sensed turbine inlet pressure.
9. The method according to claim 8 , wherein the reduced turbine mass flow rate is determined using the following relationship:
M turbine — reduced =f turbine — map ( S ,PR turbine )
wherein: M turbine — reduced is the reduced turbine mass flow rate, f turbine — map is a mapped turbine function, S is a VGT vane pulse width modulation value, and PR turbine is a VGT pressure ratio.
10. The method according to claim 1 , wherein the plurality of non-sensed vehicle operating parameters includes a non-sensed turbine inlet temperature, the non-sensed turbine inlet temperature being determined using a sensed intake manifold temperature, an engine exhaust energy fraction, a mass fueling rate, and the non-sensed intake mass flow rate.
11. The method according to claim 10 , wherein the non-sensed turbine inlet temperature is determined using the following relationship:
T
T
I
=
I
M
T
+
L
H
V
*
F
exh_energy
*
M
fueling
Cp
exh
*
M
intake
wherein: TTI is the non-sensed inlet turbine temperature, IMT is the sensed intake manifold temperature, LHV is a lower heat value of the fuel, F exh — energy is the engine exhaust energy fraction, M fueling is the mass fueling rate, Cp exh is a specific heat of the exhaust gas, and M intake is the non-sensed intake mass flow rate.
12. The method according to claim 1 , wherein a non-sensed turbine inlet pressure is determined using a non-sensed turbine inlet temperature, a mass fueling rate, a non-sensed intake mass flow rate, a non-sensed EGR mass flow rate, and the non-sensed turbine mass flow rate.
13. The method according to claim 12 , wherein the non-sensed turbine inlet pressure is determined using the following relationship:
·
V
exh_manifold
R
exh_gas
ⅆ
ⅆ
t
(
T
P
I
T
T
I
)
=
M
fueling
+
M
intake
-
M
EGR
-
M
turbine
wherein: V exh — manifold is a exhaust manifold volume, R exh — gas is an exhaust gas constant, TPI is the non-sensed turbine inlet pressure, TTI is the non-sensed turbine inlet temperature, M Fueling is the mass fueling rate, M intake is the non-sensed intake mass flow rate, M EGR is the non-sensed EGR mass flow rate, and M turbine is the non-sensed turbine mass flow rate.
14. A method for controlling emissions of a vehicle system, the method comprising:
determining a non-sensed EGR mass flow rate, a non-sensed air intake mass flow rate, a non-sensed turbine mass flow rate, a non-sensed turbine inlet temperature, and a non-sensed turbine inlet pressure using a plurality of sensed vehicle operating parameters;
determining an engine air mass flow rate of the engine using the non-sensed EGR mass flow rate, the non-sensed air intake mass flow rate, the non-sensed turbine mass flow rate, the non-sensed turbine inlet temperature, and the non-sensed turbine inlet pressure;
determining a plurality of vehicle operating set-points using the non-sensed EGR mass flow rate, the non-sensed air intake mass flow rate, the non-sensed turbine mass flow rate, the non-sensed turbine inlet temperature, the non-sensed turbine inlet pressure, and the engine air mass flow rate; and
determining future operations of the vehicle system using the determined vehicle operating set-points, wherein the determined future operations are used to modify the determined vehicle operating set-points in order to control the emissions of the vehicle system.
15. The method according to claim 14 , wherein the sensed vehicle operating parameters include an intake manifold pressure, an intake manifold temperature, and a vehicle engine speed.
16. A system for use in controlling emissions of a vehicle system, the system comprising:
a plurality of hardware sensors providing a plurality of sensed vehicle operating parameters, the plurality of hardware sensors including an intake manifold pressure sensor, an intake manifold temperature sensor, and a vehicle engine speed sensor; and
a controller configured for:
determining a plurality of non-sensed vehicle operating parameters based upon the data provided from the plurality of sensed vehicle operating parameters;
determining a non-sensed engine air mass flow rate based upon the determined non-sensed vehicle operating parameters;
determining a plurality of vehicle operating set-points using the non-sensed vehicle operating parameters and the non-sensed engine air mass flow rate; and
controlling emissions of the vehicle system using the determined vehicle operating set-points.
17. The method according to claim 16 , wherein the non-sensed vehicle operating parameters include a non-sensed air intake mass flow rate, the non-sensed air intake mass flow rate being determined using the following relationship:
M
intake
=
V
disp
RPM
engine
*
I
M
P
120
*
R
gas
*
I
M
T
η
vol
wherein: M intake is the non-sensed intake mass flow rate, V disp is a displacement volume, RPM engine is a sensed vehicle engine speed, IMP is a sensed intake manifold pressure, R gas is a gas constant, IMT is a sensed intake manifold temperature, and N vol is a volumetric efficiency ratio.
18. The method according to claim 16 , wherein the non-sensed vehicle operating parameters include a non-sensed EGR mass flow rate, the non-sensed EGR mass flow rate being determined using the following relationship:
M
EGR
2
*
T
T
I
T
P
I
*
Disc
C
2
=
C
1
*
Δ
P
+
C
2
wherein: M EGR is the non-sensed EGR mass flow rate, TTI is a non-sensed turbine inlet temperature, TPI is a non-sensed turbine inlet pressure, DisC is an EGR valve discharge coefficient, C 1 is a constant value dependent upon the vehicle system, C 2 is a function of a sensed vehicle engine speed and a vehicle engine load, and ΔP is a engine pressure differential.
19. The method according to claim 16 , wherein the non-sensed vehicle operating parameters include a non-sensed turbine mass flow rate, the non-sensed turbine mass flow rate being determined using the following relationship:
M
turbine
=
M
turbine_reduced
*
T
P
I
T
T
I
wherein: M turbine is the non-sensed turbine mass flow rate, M turbine — reduced is a reduced turbine mass flow rate, TTI is a non-sensed turbine inlet temperature, and TPI is a non-sensed turbine inlet pressure.