Fuel economy optimization using air-per-cylinder (APC) in MPC-based powertrain control

Patent metadata

Field	Value
Publication number	US-10399574-B2
Application number	US-201715697748-A
Country	US
Kind code	B2
Filing date	Sep 7, 2017
Priority date	Sep 7, 2017
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

A propulsion system, control system, and method are provided for optimizing fuel economy, which use model predictive control systems to generate a plurality of sets of possible command values and determine a cost for each set of possible command values of based on a first predetermined weighting value, a second predetermined weighting value, a plurality of predicted values, and a plurality of requested values. The set of possible command values having the lowest cost is determined and defined as a set of selected command values. Fuel is minimized by minimizing engine power for a requested axle power. Accordingly, a fuel consumption rate requested value is determined based on an air-per-cylinder (APC) requested value.

First claim

What is claimed is:

1. A method for controlling a propulsion system of a motor vehicle, the method comprising:
generating a plurality of sets of possible command values;
determining a cost for each set of possible command values of the plurality of sets of possible command values based on a first predetermined weighting value, a second predetermined weighting value, a plurality of predicted values, and a plurality of requested values, the plurality of requested values including a fuel consumption rate requested value;
determining the fuel consumption rate requested value based on an air-per-cylinder (APC) requested value;
determining which set of possible command values of the plurality of sets of possible command values has a lowest cost;
selecting the set of possible command values that has the lowest cost to define a set of selected command values; and
controlling a vehicle parameter based on the selected command value.

2. The method of claim 1 , further comprising selecting the APC requested value from the lower of a computed APC reference value and a measured APC value.

3. The method of claim 2 , further comprising determining the computed APC reference value based on an estimated engine speed and an axle power requested value.

4. The method of claim 2 , further comprising determining the computed APC reference value based on a raw APC reference value (APC r_raw ), the method further comprising determining the raw APC reference value (APC r_raw ) based on the following equation:

APC
r_raw

=

k
*

P
a_r

*
FP
*
AF

c
*
RPM

where APC r_raw is the raw APC reference value, k is a constant, P a_r is an axle power requested value, FP is a firing period, AF is an air/fuel ratio, c is an engine power-to-fuel ratio, and RPM is an estimated engine speed.

5. The method of claim 4 , further comprising determining the axle power requested value (P a_r ) based on the following equation:

P
a_r

=

Ta_r
*
V

radius
*
3600

where P a_r is the axle power requested value, Ta_r is an axle torque requested value, V is vehicle speed, and radius is wheel radius.

6. The method of claim 5 , further comprising determining the engine power-to-fuel ratio c based on an engine power requested value divided by a fuel requested value, wherein each of the engine power requested value and the fuel requested value are functions of the estimated engine speed (RPM) and an engine torque requested value, the method further comprising determining the estimated engine speed (RPM) based on the vehicle speed (V) and a transmission ratio requested value.

7. The method of claim 6 , wherein the plurality of sets of possible command values includes a plurality of commanded engine output torque values and the set of selected command values includes a selected engine output torque value, the method further comprising:
generating a plurality of predicted actual axle torque values and a plurality of predicted actual fuel consumption rate values based on the plurality of sets of possible command values, the plurality of sets of possible command values including a plurality of possible commanded transmission ratio values; and
determining the cost for each set of possible command values further based on a predicted actual axle torque value of the plurality of predicted axle torque values and a predicted actual fuel consumption rate value of the plurality of predicted actual fuel consumption rate values.

8. The method of claim 7 , further comprising determining the plurality of predicted actual axle torque values and the plurality of predicted actual fuel consumption rate values with the following set of equations:

x

k
+
1

=

{

A
*

x
k

+

B
*

[

Te_c

Rat_c
k

]

+
v

}

+

K
KF

*

(

[

Te_m
k

FR_m
k

Rat_m
k

Ta_m
k

]

-

[

Assignees

• Gm Global Tech Operations Llc

Inventors

• Livshiz Michael
• Bernardini Daniele
• Bemporad Alberto
• Pattipati Bharath

Classifications

• B60W2510/105

  Output torque · CPC title

• B60W50/0097 Primary

  Predicting future conditions · CPC title

• F02D2041/1412

  using a predictive controller · CPC title

• B60W2510/0638

  Engine speed · CPC title

• B60W10/06

  including control of combustion engines · CPC title