Control device for internal combustion engine

1. An internal combustion engine control apparatus for combustion pressure detection, comprising:

a combustion pressure sensor configured to couple to a first cylinder and to output a combustion pressure signal;

a crank angle sensor for a crankshaft, the crank angle sensor configured to output a crank signal;

a memory; and

a processor communicatively coupled to each of the memory, the combustion pressure sensor, and the crank angle sensor, the processor configured to:

at a first time:

detect a first crank signal,

detect a combustion pressure signal,

calculate a relationship between the first crank signal and the combustion pressure signal, and

store, in the memory, the relationship,

at a subsequent time, detect a subsequent crank signal,

obtain in-cylinder pressure of the first cylinder by collating the subsequent crank signal the relationship.

2. The internal combustion engine control apparatus according to claim 1 ,

wherein

the crank angle sensor is for detecting angular velocity of the crankshaft, and the crank signal reflects an angular velocity; and

the processor is configured to:

over a first time period:

detect a plurality of first crank signals and a corresponding plurality of combustion pressure signals according to a plurality of engine speed or torque states,

resolve each of the plurality of crank signals into a corresponding frequency component of the crank shaft,

calculate a plurality of relationships between the crank signals and the corresponding combustion pressure signals, and

record, to the memory, the frequency components and the plurality of relationships as a learning database, and

at a second time after the first time period:

detect a second crank signal,

resolve the second crank signal into a second frequency component,

select a reference frequency component from the learning database, wherein the reference frequency component is closest to the second frequency component, and

obtain the in-cylinder pressure based on a relationship of the plurality of relationships in the learning database that corresponds to the selected reference frequency component.

3. The internal combustion engine control apparatus according to claim 1 ,

wherein the processor is configured to:

detect a second crank signal,

correct the second crank signal to correspond to a second cylinder, and

obtain the in-cylinder pressure of the second cylinder by collating the corrected second crank signal with the relationship.

4. An internal combustion engine control apparatus that controls an internal combustion engine including a plurality of cylinders, comprising:

an internal combustion engine including a plurality of cylinders and a crankshaft;

a first combustion pressure sensor operatively coupled to a first cylinder of the plurality of cylinders and configured to produce a combustion pressure signal;

a crank angle sensor for a crankshaft, the crank angle sensor configured to produce a crank signal;

a memory; and

a processor communicatively coupled to the memory, the processor configured to:

determine, at a first time, a relationship between the first crank signal and the combustion pressure signal,

store the relationship in the memory, and

on a condition that the first combustion pressure sensor fails;

detect a crank signal,

correct the detected crank signal to correspond to the first cylinder, and

obtain an in-cylinder pressure of the first cylinder by collating the corrected crank signal with the relationship.

5. The internal combustion engine control apparatus according to claim 4 , wherein

the processor is configured to:

over a first time period:

detect, according to a plurality of engine speed or torque states, a plurality of first crank signals and a corresponding plurality of combustion pressure signals from the first combustion pressure sensor,

resolve each of the plurality of crank signals into a corresponding frequency component of the crank shaft,

calculate a plurality of relationships between the crank signals and the corresponding combustion pressure signals, and

record, to the memory, the frequency components and the plurality of relationships as a learning database, and

at a second time after the first time period:

detect a second crank signal,

resolve the second crank signal into a second frequency component,

select a reference frequency component from the learning database, wherein the reference frequency component is closest to the second frequency component, and

obtain the in-cylinder pressure of a second cylinder based on a relationship of the plurality of relationships in the learning database that corresponds to the selected reference frequency component.

6. The internal combustion engine control apparatus according to claim 4 , wherein the processor is configured to control the internal combustion engine based on the obtained in-cylinder pressure of the cylinder by adjusting at least one of a fuel injection amount, a fuel injection timing, or an ignition timing.