Adaptive machine learning method to predict and control engine combustion

Patent metadata

Field	Value
Publication number	US-10030602-B2
Application number	US-201514806037-A
Country	US
Kind code	B2
Filing date	Jul 22, 2015
Priority date	Jul 22, 2014
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A method is provided for controlling an internal combustion engine on a cycle-by-cycle basis. The method includes: maintaining training data used to identify a mapping function for the engine; populating a buffer with adaptive data for a given cylinder, where the adaptive data are measures of the inputs and the output of the mapping function that were captured during a number of recent operating cycles of the given cylinder; combining training data for the mapping function with the adaptive data; identifying the mapping function from the combined data set using a weighted least squares method; predicting a combustion feature of the given cylinder in the next cycle using the mapping function and measures of the inputs during the present cycle; and controlling the engine based in part on the predicted combustion feature of the given cylinder in the next cycle using one or more actuators.

First claim

What is claimed is:

1. A method for controlling an internal combustion engine on a cycle-by-cycle basis, comprising:
(a) providing, by a controller, a mapping function which defines a relationship between inputs and an output associated with the internal combustion engine, where the output is a given combustion feature of a given cylinder in the engine at a next cycle and the inputs include the given combustion feature of the given cylinder in a present combustion cycle and parameters indicative of mixture state and composition or engine actuator settings from one cycle to the next cycle;
(b) maintaining, by the controller, training data used to identify the mapping function in a data store associated with the controller, where the training data is measures of the inputs and the outputs of the internal combustion engine over a range of operating conditions;
(c) populating, by the controller, a buffer with adaptive data for the given cylinder in the present combustion cycle, where the adaptive data are measures of the inputs and the output of the mapping function that were captured during m most recent combustion cycles of the given cylinder;
(d) combining, by the controller, the training data with the adaptive data to form a combined data set, where the training data excludes the adaptive data;
(e) identifying, by the controller, the mapping function from the combined data set using a weighted least squares method;
(f) predicting, by the controller, the given combustion feature of the given cylinder in the next cycle using the mapping function and measures of the inputs during the present cycle;
(g) controlling, by the controller, the engine by actuating fuel injectors or another actuator in the engine based in part on the predicted combustion feature of the given cylinder in the next cycle; and
(h) repeating steps c) - g) for subsequent combustion cycles of the internal combustion engine.

2. The method of claim 1 wherein the given combustion feature is selected from a group consisting of combustion timing, combustion duration, total heat release quantity, pressure rise rate, location of peak pressure, ion current, knock intensity, and flame vs. auto ignition fraction.

3. The method of claim 1 wherein the engine has one or more pistons driven by a crankshaft, the output for the mapping function is defined as combustion timing of the given cylinder in the next cycle, and the inputs for the mapping function being selected from a group consisting of combustion timing of the given cylinder in present cycle, an indicator of fuel injected into the given cylinder in the present cycle, crank angle(s) at which fuel injection occurred in the present cycle and one or more pressure measures made inside the given cylinder.

4. The method of claim 1 wherein providing a mapping function further comprises
defining the mapping function, wherein the inputs of the mapping function are selected from a group consisting of combustion timing of the given cylinder in present cycle, an indicator of fuel injected into the given cylinder in the present cycle, crank angle at which fuel injection occurred in the present cycle and one or more pressure measures made inside the given cylinder;
capturing measurements of the inputs during a present cycle and corresponding combustion timing of the given cylinder at the next cycle while varying operating conditions of the engine;
storing the captured measurements of the inputs and the output as the training data;
determining a matrix that scales one or more transformations of the inputs of the mapping function to the output of the mapping function using a least squares method, such that the matrix serves as the mapping function for the engine; and
downloading the training data into the data store associated with the controller.

5. The method of claim 1 wherein populating a buffer further comprises capturing measures of pressure inside the given cylinder during the recent operating cycles.

6. The method of claim 1 wherein the buffer is further defined as a ring buffer.

7. The method of claim 1 wherein identifying the mapping function further comprises machine learning the mapping function with a single-hidden layer feedforward neural network with randomly chosen weights for each of the hidden nodes in the neural network.

8. The method of claim 1 further comprises repeating steps (c) - (g) for subsequent combustion cycles in the engine.

9. The method of claim 1 wherein controlling the engine further comprises determining crank angle at which to inject fuel during the next cycle in accordance with

SOI

n
+
1

=

SOI
n

-

f
⁡

(

SOI
n

)

-

target
⁢

⁢
CA
⁢

⁢
50

f
′

⁡

(

SOI
n

)

where SOI n is crank angle at which fuel injection occurred in the present cycle, f(SOI n ) is the adapted mapping function as a function of SOI while holding other inputs fixed, f′(SOI n ) is the derivative of f(SOI n ) with respect to SOI, and target CA50 is the desired combustion timing of the given cylinder in the next cycle.

10. The method of claim 1 wherein controlling the engine further comprises determining crank angle at which to inject fuel during the next cycle using gradient descent with multiple actuators.

11. A method for predicting combustion timing of an internal combustion engine, the engine having two or more pistons driven by a crankshaft, comprising:
defining, by a controller, a mapping function for the internal combustion engine, where the mapping function defines combustion timing of a given cylinder in the engine at a next cycle in terms of inputs selected from a group consisting of combustion timing of the given cylinder in present cycle, an indicator of fuel injected into the given cylinder in the present cycle, crank angle at which fuel injection occurred in the present cycle and one or more pressure measures made inside the given cylinder;
capturing, by the controller, measurements of the inputs and corresponding combustion timing of the given cylinder at the next cycle during varied operating conditions of the engine;
determining, by the controller, a vector that scales the inputs of the mapping function to the output of the mapping function using a least squares method, wherein the vector identifies the mapping function;

Assignees

• Univ Michigan Regents

Inventors

• Vaughan Adam

Classifications

• F02D41/401

  Controlling injection timing (F02D41/402 takes precedence) · CPC title

• F02D35/021

  using an ionic current sensor · CPC title

• F02D2041/1412

  using a predictive controller · CPC title

• F02D35/028

  by determining the combustion timing or phasing · CPC title

• F02D41/1405

  Neural network control · CPC title