Engine control apparatus

Abstract

In an engine control apparatus, a target engine torque after an environment correction is calculated by interpolating it between an environmentally corrected maximum engine torque and an environmentally corrected minimum engine torque according to a target torque ratio which is a ratio of the target engine torque between the maximum engine torque and the minimum engine torque under a predetermined environmental condition. The maximum engine torque and the minimum engine torque are set based on a smoothed maximum engine torque and a smoothed minimum engine torque obtained by smoothing out a change over time in an estimated maximum engine torque and an estimated minimum engine torque currently able to be output according to a change in the environmental condition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and/or further objects, features and advantages of the invention will become apparent from the following description of example embodiments with reference to the accompanying drawings, in which the same or corresponding portions are denoted by the same reference numerals and wherein:

FIG. 1 is a block diagram of the configuration of an engine ECU which serves as the engine control apparatus according to an example embodiment of the invention;

FIG. 2 is a flowchart illustrating the control structure of a routine for setting the target engine torque according to the example embodiment;

FIG. 3 is a conceptual diagram of an example of a conversion characteristic of an accelerator opening amount;

FIG. 4 is a conceptual diagram of an example structure of a nominal torque map showing the engine torque characteristics with respect to the converted accelerator opening amount and the engine speed under a predetermined environmental condition;

FIG. 5 is a conceptual diagram illustrating an example of the affect of atmospheric pressure on the maximum engine torque;

FIG. 6 is a conceptual diagram showing the details of the calculation of the environmentally corrected target engine torque;

FIGS. 7A and 7B are a conceptual diagrams of a smoothing process on the changes over time in the minimum engine torque and maximum engine torque, respectively; and

FIG. 8 is a conceptual diagram of an example of a target engine torque setting according to this example embodiment.

Claims

1. An engine control apparatus which obtains a target engine torque based on an accelerator operation amount and performs engine control such that an output torque of an engine becomes equal to the target engine torque, comprising: a nominal calculating portion that calculates a nominal maximum engine torque, a nominal minimum engine torque and a nominal target engine torque based on characteristics of engine torque with respect to an engine speed and the accelerator operation amount obtained in advance under a predetermined environmental condition;an estimating portion that estimates a maximum engine torque and a minimum engine torque based on the environmental condition;a smoothing portion which smoothes out a change over time in the estimated minimum engine torque to obtain a smoothed minimum engine torque, and sets an environmentally corrected minimum engine torque based on the smoothed minimum engine torque; anda setting portion that sets the target engine torque by interpolating the target engine torque between the estimated maximum engine torque and the environmentally corrected minimum engine torque such that the ratio of the nominal target engine torque between the nominal maximum engine torque and the nominal minimum engine torque becomes essentially equal to the ratio of the target engine torque between the estimated maximum engine torque and the environmentally corrected minimum engine torque.

2. The engine control apparatus according to claim 1, wherein the setting portion sets the target engine torque by interpolating the target engine torque between the estimated maximum engine torque and the environmentally corrected minimum engine torque such that the ratio of the difference between the nominal maximum engine torque and the nominal minimum engine torque to the difference between the nominal target engine torque and the nominal minimum engine torque becomes essentially equal to the ratio of the difference between the estimated maximum engine torque and the environmentally corrected minimum engine torque to the difference between the target engine torque and the environmentally corrected minimum engine torque.

3. An engine control apparatus which obtains a target engine torque based on an accelerator operation amount and performs engine control such that an output torque of an engine becomes equal to the target engine torque, comprising: a nominal calculating portion that calculates a nominal maximum engine torque, a nominal minimum engine torque and a nominal target engine torque based on characteristics of engine torque with respect to an engine speed and the accelerator operation amount obtained in advance under a predetermined environmental condition;an estimating portion that estimates a maximum engine torque and a minimum engine torque based on the environmental condition;a smoothing portion which smoothes out a change over time in the estimated maximum engine torque to obtain a smoothed maximum engine torque, and sets an environmentally corrected maximum engine torque based on the smoothed maximum engine torque; anda setting portion that sets the target engine torque by interpolating the target engine torque between the environmentally corrected maximum engine torque and the estimated minimum engine torque such that the ratio of the nominal target engine torque between the nominal maximum engine torque and the nominal minimum engine torque becomes essentially equal to the ratio of the target engine torque between the environmentally corrected maximum engine torque and the estimated minimum engine torque.

4. The engine control apparatus according to claim 3, wherein the setting portion sets the target engine torque by interpolating the target engine torque between the environmentally corrected maximum engine torque and the estimated minimum engine torque such that the ratio of the difference between the nominal maximum engine torque and the nominal minimum engine torque to the difference between the nominal target engine torque and the nominal minimum engine torque becomes essentially equal to the ratio of the difference between the environmentally corrected maximum engine torque and the estimated minimum engine torque to the difference between the target engine torque and the estimated minimum engine torque.

5. An engine control apparatus which obtains a target engine torque based on an accelerator operation amount and performs engine control such that an output torque of an engine becomes equal to the target engine torque, comprising: a nominal calculating portion that calculates a nominal maximum engine torque, a nominal minimum engine torque and a nominal target engine torque based on characteristics of engine torque with respect to an engine speed and the accelerator operation amount obtained in advance under a predetermined environmental condition;an estimating portion that estimates a maximum engine torque and a minimum engine torque based on the environmental condition;a smoothing portion which smoothes out a change over time in the estimated maximum engine torque and the estimated minimum engine torque to obtain a smoothed maximum engine torque and a smoothed minimum engine torque, respectively, and sets an environmentally corrected maximum engine torque and an environmentally corrected minimum engine torque based on the smoothed maximum engine torque and the smoothed minimum engine torque, respectively; anda setting portion that sets the target engine torque by interpolating the target engine torque between the environmentally corrected maximum engine torque and the environmentally corrected minimum engine torque such that the ratio of the nominal target engine torque between the nominal maximum engine torque and the nominal minimum engine torque becomes essentially equal to the ratio of the target engine torque between the environmentally corrected maximum engine torque and the environmentally corrected minimum engine torque.

6. The engine control apparatus according to claim 5, wherein the setting portion sets the target engine torque by interpolating the target engine torque between the environmentally corrected maximum engine torque and the environmentally corrected minimum engine torque such that the ratio of the difference between the nominal maximum engine torque and the nominal minimum engine torque to the difference between the nominal target engine torque and the nominal minimum engine torque becomes essentially equal to the ratio of the difference between the environmentally corrected maximum engine torque and the environmentally corrected minimum engine torque to the difference between the target engine torque and the environmentally corrected minimum engine torque.

7. The engine control apparatus according to claim 1, wherein the smoothing portion smoothes out a change over time in the estimated minimum engine torque according to a predetermined smoothing degree; and the smoothing degree is set, according to the accelerator operation amount, smaller when the accelerator operation amount is less than a predetermined value than when the accelerator operation amount is equal to or greater than the predetermined value.

8. The engine control apparatus according to claim 5, wherein the smoothing portion smoothes out a change over time in the estimated minimum engine torque according to a predetermined smoothing degree; and the smoothing degree is set, according to the accelerator operation amount, smaller when the accelerator operation amount is less than a predetermined value than when the accelerator operation amount is equal to or greater than the predetermined value.

9. The engine control apparatus according to claim 1, wherein when the accelerator operation amount is minimal, the smoothing portion sets the estimated minimum engine torque, instead of the smoothed minimum engine torque, to the environmentally corrected minimum engine torque used by the setting portion.

10. The engine control apparatus according to claim 5, wherein when the accelerator operation amount is minimal, the smoothing portion sets the estimated minimum engine torque, instead of the smoothed minimum engine torque, to the environmentally corrected minimum engine torque used by the setting portion.

11. The engine control apparatus according to claim 3, wherein the smoothing portion smoothes out a change over time in the estimated maximum engine torque according to a predetermined smoothing degree; and the smoothing degree is set, according to the accelerator operation amount, smaller when the accelerator operation amount is greater than a predetermined value than when the accelerator operation amount is equal to or less than the predetermined value.

12. The engine control apparatus according to claim 5, wherein the smoothing portion smoothes out a change over time in the estimated maximum engine torque according to a predetermined smoothing degree; and the smoothing degree is set, according to the accelerator operation amount, smaller when the accelerator operation amount is greater than a predetermined value than when the accelerator operation amount is equal to or less than the predetermined value.

13. The engine control apparatus according to claim 3, wherein when the accelerator operation amount is maximal, the smoothing portion sets the estimated maximum engine torque, instead of the smoothed maximum engine torque, to the environmentally corrected maximum engine torque used by the setting portion.

14. The engine control apparatus according to claim 5, wherein when the accelerator operation amount is maximal, the smoothing portion sets the estimated maximum engine torque, instead of the smoothed maximum engine torque, to the environmentally corrected maximum engine torque used by the setting portion.

15. An engine control apparatus which obtains a target engine torque based on an accelerator operation amount and performs engine control such that an output torque of an engine becomes equal to the target engine torque, comprising: nominal calculating means for calculating a nominal maximum engine torque, a nominal minimum engine torque and a nominal target engine torque based on characteristics of engine torque with respect to an engine speed and the accelerator operation amount obtained in advance under a predetermined environmental condition;estimating means for estimating a maximum engine torque and a minimum engine torque based on the environmental condition;smoothing means for smoothing out a change over time in the estimated minimum engine torque to obtain a smoothed minimum engine torque, and setting an environmentally corrected minimum engine torque based on the smoothed minimum engine torque; andsetting means for setting the target engine torque by interpolating the target engine torque between the estimated maximum engine torque and the environmentally corrected minimum engine torque such that the ratio of the nominal target engine torque between the nominal maximum engine torque and the nominal minimum engine torque becomes essentially equal to the ratio of the target engine torque between the estimated maximum engine torque and the environmentally corrected minimum engine torque.

16. An engine control apparatus which obtains a target engine torque based on an accelerator operation amount and performs engine control such that an output torque of an engine becomes equal to the target engine torque, comprising: nominal calculating means for calculating a nominal maximum engine torque, a nominal minimum engine torque and a nominal target engine torque based on characteristics of engine torque with respect to an engine speed and the accelerator operation amount obtained in advance under a predetermined environmental condition;estimating means for estimating a maximum engine torque and a minimum engine torque based on the environmental condition;smoothing means for smoothing out a change over time in the estimated maximum engine torque to obtain a smoothed maximum engine torque, and setting an environmentally corrected maximum engine torque based on the smoothed maximum engine torque; andsetting means for setting the target engine torque by interpolating the target engine torque between the environmentally corrected maximum engine torque and the estimated minimum engine torque such that the ratio of the nominal target engine torque between the nominal maximum engine torque and the nominal minimum engine torque becomes essentially equal to the ratio of the target engine torque between the environmentally corrected maximum engine torque and the estimated minimum engine torque.

17. An engine control apparatus which obtains a target engine torque based on an accelerator operation amount and performs engine control such that an output torque of an engine becomes equal to the target engine torque, comprising: nominal calculating means for calculating a nominal maximum engine torque, a nominal minimum engine torque and a nominal target engine torque based on characteristics of engine torque with respect to an engine speed and the accelerator operation amount obtained in advance under a predetermined environmental condition;estimating means for estimating a maximum engine torque and a minimum engine torque based on the environmental condition;smoothing means for smoothing out a change over time in the estimated maximum engine torque and the estimated minimum engine torque to obtain a smoothed maximum engine torque and a smoothed minimum engine torque, respectively, and setting an environmentally corrected maximum engine torque and an environmentally corrected minimum engine torque based on the smoothed maximum engine torque and the smoothed minimum engine torque, respectively; andsetting means for setting the target engine torque by interpolating the target engine torque between the environmentally corrected maximum engine torque and the environmentally corrected minimum engine torque such that the ratio of the nominal target engine torque between the nominal maximum engine torque and the nominal minimum engine torque becomes essentially equal to the ratio of the target engine torque between the environmentally corrected maximum engine torque and the environmentally corrected minimum engine torque.