Control system of internal combustion engine

Patent metadata

Field	Value
Publication number	US-9938923-B2
Application number	US-201715408928-A
Country	US
Kind code	B2
Filing date	Jan 18, 2017
Priority date	Jan 27, 2016
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A control system of an internal combustion engine includes a port injection valve and an electronic control unit. The electronic control unit is configured to: (i) obtain one of a start crank angle and an end crank angle, (ii) calculate the other of the start crank angle and the end crank angle, based on an equation for calculating a provisional injection amount of the case where the port injection valve provisionally injects the fuel with the one of the start crank angle and the end crank angle and a given crank angle range; (iii) convert a crank angle range from the start crank angle to the end crank angle, into a target energization period; and (iv) perform fuel injection by energizing the port injection valve for the target energization period.

First claim

What is claimed is:

1. A control system of an internal combustion engine, comprising:
a direct injection valve configured to directly inject a fuel into a cylinder of the internal combustion engine;
a port injection valve configured to inject the fuel into an intake port of the internal combustion engine;
a low-pressure pump configured to pressurize the fuel;
a low-pressure fuel supply passage through which the fuel pressurized by the low-pressure pump is supplied to the port injection valve;
a high-pressure pump operatively linked with the internal combustion engine and configured to be driven by the internal combustion engine, the high-pressure pump being configured to further pressurize the fuel supplied from the low-pressure fuel supply passage, such that pulsation of a fuel pressure is generated in the low-pressure fuel supply passage;
a high-pressure fuel supply passage through which the fuel pressurized by the high-pressure pump is supplied to the direct injection valve;
a crank angle sensor configured to detect a crank angle of the internal combustion engine; and
an electronic control unit configured to:
(i) calculate a required injection amount of the fuel required to be injected from the port injection valve, based on conditions of the internal combustion engine;
(ii) obtain one of a start crank angle and an end crank angle, the start crank angle being a crank angle corresponding to a scheduled start time of fuel injection of the port injection valve, the end crank angle being a crank angle corresponding to a scheduled end time of fuel injection of the port injection valve;
(iii) calculate the other of the start crank angle and the end crank angle, based on an equation of Q p below for calculating a provisional injection amount of a case where the port injection valve provisionally injects the fuel with the one of the start crank angle and the end crank angle and a given crank angle range, such that a value obtained by subtracting a provisional injection amount from a base crank angle corresponding to an initial phase of the pulsation to the start crank angle, from a provisional injection amount from the base crank angle to the end crank angle becomes equal to the required injection amount,

Q
p

=

k

360
·
Ne

⁢

∫

P
⁡

(
θ
)

⁢
d
⁢

⁢
θ

where, Q p is the provisional injection amount, k is a constant, and Ne is a rotational speed of the internal combustion engine, θ is the crank angle, P is a fuel pressure value corresponding to the crank angle, P is calculated by equation below,
P (θ)= A cos { c (θ− B )}+ P c

where, A is an amplitude of the pulsation, c is the number of times of discharge of the fuel from the high-pressure pump per 360 degrees of the crank angle, B is the initial phase of the pulsation, P c is a center fuel pressure value of the pulsation;
(iv) convert a crank angle range from the start crank angle to the end crank angle, into a target energization period; and
(v) perform fuel injection by energizing the port injection valve for the target energization period.

2. The control system of the internal combustion engine according to claim 1 , further comprising:
a fuel pressure sensor configured to detect the fuel pressure in the low-pressure fuel supply passage, wherein
the electronic control unit is configured to:
(vi) obtain a detection value of the fuel pressure sensor at fixed sampling time intervals;
(vii) determine whether the start crank angle is between a first crank angle at a point in time at which the detection value of the fuel pressure sensor as a first latest fuel pressure value is obtained, and a second crank angle at a point in time at which the detection value is scheduled to be obtained next time, the first latest fuel pressure value being obtained most recently; and
(viii) calculate the other of the start crank angle and the end crank angle, when the electronic control unit determines that the start crank angle is between the first crank angle and the second crank angle.

3. The control system of the internal combustion engine according to claim 1 , further comprising:
a fuel pressure sensor configured to detect the fuel pressure in the low-pressure fuel supply passage, wherein:
the electronic control unit includes a memory that stores a number of times of discharge of the fuel from the high-pressure pump per 360 degrees of the crank angle; and
the electronic control unit is configured to:
(ix) obtain a detection value of the fuel pressure sensor at fixed sampling time intervals; and
(x) calculate a center fuel pressure value of the pulsation, an amplitude of the pulsation, and an initial phase of the pulsation, based on at least a first latest fuel pressure value, a second latest fuel pressure value, and a third latest fuel pressure value as detection values of the fuel pressure sensor, the first latest fuel pressure value being obtained most recently, the second latest fuel pressure value being obtained immediately before the first latest fuel pressure value is obtained, the third latest fuel pressure value being obtained immediately before the second latest fuel pressure value.

4. The control system of the internal combustion engine according to claim 3 , wherein the electronic control unit is configured to calculate the amplitude of the pulsation, based on the second latest fuel pressure value and the first latest fuel pressure value as the detection values of the fuel pressure sensor, and the crank angle corresponding to the sampling time interval.

5. The control system of the internal combustion engine according to claim 4 , wherein the electronic control unit is configured to calculate the initial phase of the pulsation, based on one of the second latest fuel pressure value and the first latest fuel pressure value as the detection values of the fuel pressure sensor, the crank angle at a time when the one of the second latest fuel pressure value and the first latest fuel pressure value is obtained, the number of times of discharge from the high-pressure pump per 360 degrees of the crank angle, the calculated amplitude of the pulsation, and the calculated center fuel pressure value of the pulsation.

6. The control system of the internal combustion engine according to claim 1 , wherein the electronic control unit is configured to:
(xi) determine whether a rotational speed of the internal combustion engine belongs to a pulsation increase region in which the pulsation increases as compared with other rotational speed regions of the internal combustion engine; and
(xii) calculate the other of the start crank angle and the end crank angle, when the rotational speed of the internal combustion engine belongs to the pulsation increase region.

Assignees

• Toyota Motor Co Ltd

Inventors

• Tachibana Rintarou
• Suda Tooru
• Idogawa Masanao

Classifications

• F02D2250/04

  Fuel pressure pulsation in common rails · CPC title

• F02D2200/101

  Engine speed · CPC title

• F02D41/20

  Output circuits, e.g. for controlling currents in command coils · CPC title

• F02D2200/0602

  Fuel pressure · CPC title

• F02D35/028

  by determining the combustion timing or phasing · CPC title