Control apparatus for operating a fuel metering valve

Patent metadata

Field	Value
Publication number	US-9581102-B2
Application number	US-201414446071-A
Country	US
Kind code	B2
Filing date	Jul 29, 2014
Priority date	Jul 29, 2013
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

A method and control apparatus are disclosed for operating a fuel-metering valve associated to a fuel pump arranged to supply fuel into a fuel rail, the fuel-metering valve having a valve member and an electric actuator arranged to move that member for regulating a fuel flow-rate. The control apparatus includes an electronic control unit connected to the fuel-metering valve and configured to implement a method of control using a target value, a nominal function corrected value to set an adjustable parameter of a control signal for the fuel-metering valve.

First claim

The invention claimed is:

1. A control apparatus for operating a fuel metering valve associated to a fuel pump arranged to supply fuel into a fuel rail, the fuel metering valve having a valve member and an electric actuator arranged to move the valve member for regulating a fuel flow-rate supplied by the fuel pump into the fuel rail, the control apparatus comprising an electronic control unit connected to the fuel metering valve and configured to:
determine a target value (q* tot ) for the fuel flow-rate;
use a nominal function (F n ), correlating values of the fuel flow-rate to corresponding values of an adjustable parameter of an electric signal driving the actuator of the fuel metering valve, to determine a nominal value (r n ) of the adjustable parameter that corresponds to the target value (q* tot ) of the fuel flow-rate;
use the determined nominal value (r n ) to calculate a corrected value (r*) of the adjustable parameter; and
set the adjustable parameter of the electric signal at the corrected value (r*);
wherein the electronic control unit is configured to calculate the corrected value (r*) of the adjustable parameter by:
estimating a value (q^ tot ) of the fuel flow-rate that approximates a real value (q tot ) thereof;
calculating a difference between the target value (q* tot ) and the estimated value (q^ tot ) of the fuel flow-rate;
using said difference to determine a value (Δr*) of a correction term indicative of a deviation of the nominal function (F n ); and
calculating the corrected value (r*) of the adjustable parameter as a function of the nominal value (r n ) thereof and of the calculated value (Δr*) of the correction term.

2. A control apparatus according to claim 1 , wherein the electronic control unit is configured to determine the value (Δr*) of the correction term by:
calculating a derivative of the nominal function (F n ) at the point corresponding to the target value (q* tot ) of the fuel flow-rate;
calculating a derivative of the nominal function (F n ) at the point corresponding to the estimated value (q* tot ) of the fuel flow-rate; and
calculating the correction term value (Δr*) as a function of said derivatives and of the difference between the target value (q* tot ) and the estimated value (q^ tot ) of the fuel flow-rate.

3. The control apparatus according to claim 2 , wherein the electronic control unit is configured to calculate the value (Δr*) of the correction term by:
calculating an average between the derivatives of the nominal function (F n ) calculated at the points corresponding to the target value (q* tot ) and to the estimated value (q^ tot ) of the fuel flow-rate; and
multiplying the calculated average for the difference between the target value (q* tot ) and the estimated value (q^ tot ) of the fuel flow-rate.

4. The control apparatus according to claim 3 , wherein the electronic control unit is configured to calculate the average between the derivatives of the nominal function (F n ) as an harmonic mean thereof.

5. The control apparatus according to claim 1 , wherein the electronic control unit is configured to estimate the value (q^ tot ) of the fuel flow-rate by:
measuring a value (Y) of a fuel rail pressure; and
determining the estimated value (q^ tot ) of the fuel flow-rate on the basis of the measured value (Y) of the fuel rail pressure.

6. The control apparatus according to claim 5 , wherein the electronic control unit is configured to determine the estimated value (q^ tot ) of the fuel flow-rate using the measured value (Y) of the fuel rail pressure as input of a mathematical model that yields as output the estimated value (q^ tot ) of the fuel flow-rate.

7. The control apparatus according to claim 5 , wherein the electronic control unit is configured to determine the target value (q* tot ) of the fuel flow-rate by:
setting a target value (Y*) for the fuel rail pressure;
calculating a difference between the target value (Y*) and the measured value (Y) of the fuel rail pressure; and
calculating a feedback contribution (q PI ) to the target value (q* tot ) of the fuel flow-rate as a function of the calculated difference.

8. The control apparatus according to claim 7 , wherein the electronic control unit is configured to calculate the feed-back contribution (q PI ) using the difference between the target value (Y*) and the measured value (Y) of the fuel rail pressure as input of a proportional-integrative controller ( 535 ) that yields as output the feed-back contribution (q PI ).

9. The control apparatus according to claim 7 , wherein the electronic control unit is configured to determine the target value (q* tot ) of the fuel flow-rate by:
calculating a feed-forward contribution (q* L ) to the target value (q* tot ) of the fuel flow-rate on the basis of the target value (Y*) of the fuel rail pressure; and
adding the feed-forward contribution (q* L ) to the feedback contribution (q PI ) of the fuel flow-rate.

10. The control apparatus according to claim 9 , wherein the electronic control unit is configured to calculate the feed-forward contribution (q* L ) using the target value (Y*) of the fuel rail pressure as input of a mathematical model that yields as output the feed-forward contribution (q* L ).

11. The control apparatus according to claim 1 , wherein the adjustable parameter of the electric signal driving the actuator of the fuel metering valve is an electrical current.

12. The control apparatus according to any of the claims from 1 , wherein the adjustable parameter of the electric signal driving the actuator of the fuel metering valve is a timing of a sequence of electrical current pulses forming the signal.

13. A method for operating a fuel metering valve associated to a fuel pump arranged to supply fuel into a fuel rail, the fuel metering valve having a valve member and an electric actuator arranged to move the valve member for regulating a fuel flow-rate supplied by the fuel pump into the fuel rail, the method comprising:
determining a target value (q* tot ) for the fuel flow-rate;
using a nominal function (F n ) correlating values of the fuel flow-rate to corresponding values of an adjustable parameter of an electric signal driving the actuator of the fuel metering valve, to determine a nominal value (r n ) of the adjustable parameter that corresponds to the target value (q* tot ) of the fuel flow-rate;
using the determined nominal value (r n ) to calculate a corrected value (r*) of the adjustable parameter; and
setting the adjustable parameter of the electric signal at the corrected value (r*),
wherein the corrected value (r*) of the adjustable parameter is calculated by:
estimating a value (q^ tot ) of the fuel flow-rate that approximates a real value (q tot ) thereof;
calculating a difference between the target value (q* tot ) and the estimated value (q^ tot ) of the fuel flow-rate;
using said difference to determine a value (Δr*) of a correction term indicative of a deviation of the nominal function (F n ); and
calculating the corrected value (r*) of the adjustable parameter as a function of the nominal value (r n ) thereof and of the calculated value (Δr*) of the correction term.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Nieddu Stefano

Classifications

• F02D2041/1433

  using a model or simulation of the system · CPC title

• F02D2041/141

  using a feed-forward control element · CPC title

• F02D41/1401

  characterised by the control or regulation method (F02D41/1473, F02D41/1477 take precedence) · CPC title

• F02D41/3845 Primary

  by controlling the flow into the common rail, e.g. the amount of fuel pumped · CPC title

• F02D2041/1409

  using at least a proportional, integral or derivative controller · CPC title