EP2381082A1

EP2381082A1 - Method and device for controlling operation of an injection engine

Info

Publication number: EP2381082A1
Application number: EP11163013A
Authority: EP
Inventors: Chun-Hsiung Chen
Original assignee: Kwang Yang Motor Co Ltd
Current assignee: Kwang Yang Motor Co Ltd
Priority date: 2010-04-20
Filing date: 2011-04-19
Publication date: 2011-10-26

Abstract

A device (2) for controlling operation of aninjection engine (3) includes first and second sampling conduits (211,212), a pressure sensor (221), an electromagnetic switch (231) disposed to block and unblock fluid communication between the pressure sensor (221) and each of the first and second sampling conduits (211, 212), and an electronic control unit (241) electrically coupled to the pressure sensor (221) and the electromagnetic switch (231) and disposed to receive a crankshaft rotation signal. The electronic control unit (241) is configured to control the electromagnetic switch (231) so that the pressure sensor (221) may determine a negative pressure value of a selected one of first and second cylinders (31, 32) of the injection engine (3), and is configured to perform control for ignition and fuel injection in each of the first and second cylinders (31, 32) with reference to the negative pressure value and the crankshaft rotation signal.

Description

This application claims priority of Taiwanese ApplicationsNo. 099112359 and 099112360, filed on April 20, 2010 .
The present invention relates to a method and a device for controlling operation of an internal combustion engine, more particularly to a method and a device for controlling operation of a two-cylinder injection engine.
Referring to Figure 1, a conventional two-cylinder injection engine 1 includes an air filter 11, a first throttle body 12 coupled to the air filter 11, a second throttle body 13 that is spaced apart from the first throttle body 12 and that is coupled to the air filter 11, a first cylinder 14 coupled to the first throttle body 12, a second cylinder 15 coupled to the second throttle body 13, and a pressure sensor unit 16 for acquiring a negative pressure value of the first and second cylinders 14, 15.
Referring to Figures 1 and 2, the pressure sensor unit 16 includes a first sampling conduit 161 through which a negative pressure in the first cylinder 14 is acquired, a second sampling conduit 162 through which a negative pressure in the second cylinder 15 is acquired, a pressure sensor 163 operable to sense pressure in the first and second sampling conduits 161, 162, a three-way conduit 164 coupled among the first and second sampling conduits 161, 162 and the pressure sensor 163, and an electronic control unit 165 electrically coupled to the pressure sensor 163.
The pressure sensor 163 uses the three-way conduit 164 to acquire a negative pressure value representing pressure in the first and second sampling conduits 161, 162. The electronic control unit 165 then controls ignition and fuel injection in each of the first and second cylinders 14, 15 with reference to the negative pressure value acquired by the pressure sensor 163.
However, since the three-way conduit 164 is always in fluid communication with the first and second sampling conduits 161, 162 and is coupled to the pressure sensor 163, the pressure sensor 163 may only acquire a combined negative pressure value of the first and second cylinders 14, 15, i.e., a respective negative pressure value of each of the first and second cylinders 14, 15 is not acquired. Therefore, if the electronic control unit 165 controls ignition and fuel injection in each of the first and second cylinders 14, 15 with reference to the combined negative pressure value acquired by the pressure sensor 163 when the first and second cylinders 14, 15 have substantially different characteristics resulting from an abnormal situation or carbon deposit in one of the first and second cylinders 14, 15, an excessive difference in power outputs of the first and second cylinders 14, 15 is likely to occur. Stability and durability of the first and second cylinders 14, 15 are influenced accordingly.
Therefore, an object of the present invention is to provide a method for controlling operation of individual cylinders of a two-cylinder injection engine with relative precision.
According to a first aspect, an injection engine includes first and second cylinders, a first sampling conduit through which a negative pressure in the first cylinder is acquired, a second sampling conduit through which a negative pressure in the second cylinder is acquired, a pressure sensor coupled to the first and second sampling conduits and operable to sense pressure in the first and second sampling conduits, a crankshaft position sensor for detecting crankshaft rotation of the injection engine and generating a crankshaft rotation signal corresponding to the crankshaft rotation detected thereby, and an electronic control unit electrically coupled to the pressure sensor and the crankshaft position sensor. The method of the present invention comprises:

a) configuring the electronic control unit to control an electromagnetic switch, which is disposed to block and unblock fluid communication between the pressure sensor and each of the first and second sampling conduits, so that the pressure sensor may determine a negative pressure value of a selected one of the first and second cylinders through a respective one of the first and second sampling conduits and may generate a negative pressure signal corresponding to the negative pressure value of the selected one of the first and second cylinders;
b) configuring the electronic control unit to determine a first time point where the negative pressure signal has reached a predetermined maximum value, to determine a second time point where the crankshaft position sensor detects a predetermined crankshaft angle, and to determine a crankshaft angular distance travelled between the first and second time points;
c) when the crankshaft angular distance is within a predetermined angular distance, configuring the electronic control unit to perform control for ignition and fuel injection in the selected one of the first and second cylinders once every two cycles of crankshaft rotation, in which a first amount of fuel is injected during the fuel injection; and
d) when the crankshaft angular distance is not within the predetermined angular distance, configuring the electronic control unit to perform control for ignition and fuel injection in the selected one of the first and second cylinders once every cycle of crankshaft rotation, in which a second amount of fuel is injected during the fuel injection.

Another object of the present invention is to provide a device for controlling operation of individual cylinders of a two-cylinder injection engine with relative precision.
According to a second aspect, an injection engine includes first and second cylinders, and a crankshaft position sensor for detecting crankshaft rotation of the injection engine and generating a crankshaft rotation signal corresponding to the crankshaft rotation detected thereby. The device of the present invention comprises a first sampling conduit through which a negative pressure in the first cylinder is acquired, a second sampling conduit through which a negative pressure in the second cylinder is acquired, a pressure sensor coupled to the first and second sampling conduits and operable to sense pressure in the first and second sampling conduits, an electromagnetic switch disposed to block and unblock fluid communication between the pressure sensor and each of the first and second sampling conduits, and an electronic control unit electrically coupled to the pressure sensor and the electromagnetic switch and disposed to receive the crankshaft rotation signal.
The electronic control unit is configured to control the electromagnetic switch so that the pressure sensor may determine a negative pressure value of a selected one of the first and second cylinders through a respective one of the first and second sampling conduits, and is configured to perform control for ignition and fuel injection in the selected one of the first and second cylinders with reference to the crankshaft rotation signal and the negative pressure value of the selected one of the first and second cylinders.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:

Figure 1 is a side elevation view illustrating a conventional pressure sensor unit of a two-cylinder injection engine;
Figure 2 is a schematic diagram illustrating a first sampling conduit, a second sampling conduit, a pressure sensor, a three-way conduit, and an electronic control unit of the conventional pressure sensor unit;
Figure 3 is a side elevation view illustrating a first preferred embodiment of a device for controlling operation of an injection engine of the present invention;
Figure 4 is a schematic diagram illustrating an electromagnetic switch of the first preferred embodiment in a first switch state;
Figure 5 is a schematic diagram illustrating the electromagnetic switch of the first preferred embodiment in a second switch state;
Figure 6 is a timing diagram illustrating a crankshaft rotation signal, a negative pressure signal, a fuel injection signal, and an ignition signal; and
Figure 7 is a side elevation view illustrating a second preferred embodiment of the device for controlling operation of an injection engine of the present invention.

Before the present invention is described in greater detail with reference to the preferred embodiments, it should be noted that the same reference numerals are used to denote the same elements throughout the following description.
Referring to Figure 3, a first preferred embodiment of the device 2 for controlling operation of an injection engine 3 of the present invention is illustrated. In this embodiment, the injection engine 3 is a two-cylinder injection engine.
Referring to Figure 3 and Figure 4, the injection engine 3 includes first and second cylinders 31, 32, a first throttle body 33 coupled to the first cylinder 31, a second throttle body 34 coupled to the second cylinder 32, a crankshaft 35, a flywheel 36 connected to the crankshaft 35, a plurality of teeth 37 disposed on the flywheel 36, and a crankshaft position sensor 38 for detecting the teeth 37 in association with crankshaft rotation of the injection engine 3 and generating a crankshaft rotation signal corresponding to the crankshaft rotation detected thereby. The first cylinder 31 includes a first intake valve 311. The second cylinder 32 includes a second intake valve 321.
The device 2 includes a first sampling conduit 211 through which a negative pressure in the first cylinder 31 is acquired, a second sampling conduit 212 through which a negative pressure in the second cylinder 32 is acquired, a pressure sensor 221 coupled to the first and second sampling conduits 211, 212 and operable to sense pressure in the first and second sampling conduits 211, 212, an electromagnetic switch 231 disposed to block and unblock fluid communication between the pressure sensor 221 and each of the first and second sampling conduits 211, 212, a transmission conduit 222 coupled between the electromagnetic switch 231 and the pressure sensor 221, and an electronic control unit 241 electrically coupled to the pressure sensor 221 and the electromagnetic switch 231 and disposed to receive the crankshaft rotation signal.
In the first preferred embodiment, the transmission conduit 222 is coupled between the electromagnetic switch 231 and the pressure sensor 221. However, in other configurations, the electromagnetic switch 231 may be coupled to the pressure sensor 221 directly.
In this embodiment, the first sampling conduit 211 has one end coupled to the electromagnetic switch 231, and another end coupled between the first throttle body 33 and the first intake valve 311 of the first cylinder 31. The negative pressure in the first cylinder 31 is acquired through the first sampling conduit 211. The second sampling conduit 212 has one end coupled to the electromagnetic switch 231, and another end coupled between the second throttle body 34 and the second intake valve 321 of the second cylinder 32. The negative pressure in the second cylinder 32 is acquired through the second sampling conduit 212. However, connections of the first and second sampling conduits 211, 212 to the first and second cylinders 31, 32 and the electromagnetic switch 231 should not be limited to the disclosure in this embodiment.
Referring to Figures 3, 4 and 5, the electronic control unit 241 is configured to control the electromagnetic switch 231 to switch periodically between a first switch state, in which the second sampling conduit 212 is blocked and the first sampling conduit 211 is unblocked as illustrated in Figure 4, and a second switch state, in which the first sampling conduit 211 is blocked and the second sampling conduit 212 is unblocked as illustrated in Figure 5. In the first preferred embodiment, the electromagnetic switch 231 is a two-way electromagnetic valve, and the electromagnetic switch 231 is controlled to switch once every cycle of the crankshaft rotation.
In particular, when the first intake valve 311 of the first cylinder 31 is open, the electronic control unit 241 is configured to control the electromagnetic switch 231 to switch to the first switch state as illustrated in Figure 4. At this time, the second sampling conduit 212 is blocked and the first sampling conduit 211 is unblocked so that the pressure sensor 221 may determine a negative pressure value of the first cylinder 31 through the first sampling conduit 211, as illustrated by arrows 41 in Figure 4, so as to generate a negative pressure signal (as illustrated in Figure 6) corresponding to the negative pressure value of the first cylinder 31. Therefore, the first cylinder 31 is selected when the electromagnetic switch 231 is in the first switch state. Furthermore, when the second intake valve 321 of the second cylinder 32 is open, the electronic control unit 241 is configured to control the electromagnetic switch 231 to switch to the second switch state as illustrated in Figure 5. At this time, the first sampling conduit 211 is blocked and the second sampling conduit 212 is unblocked so that the pressure sensor 221 may determine a negative pressure value of the second cylinder 32 through the second sampling conduit 212, as illustrated by arrows 42 in Figure 5, so as to generate a negative pressure signal corresponding to the negative pressure value of the second cylinder 32. Therefore, the second cylinder 32 is selected when the electromagnetic switch 231 is in the second switch state.
A first preferred embodiment of a method for controlling operation of the injection engine 3 is performed using the first preferred embodiment of the device 2 mentioned above.
Referring to Figures 4 and 6, the first preferred embodiment of the method comprises:

a) configuring the electronic control unit 241 to control the electromagnetic switch 231 to switch to the first switch state as illustrated in Figure 4 so that the pressure sensor 221 may determine the negative pressure value of the first cylinder 31 through the first sampling conduit 211, as illustrated by the arrows 41 in Figure 4, and may generate a negative pressure signal corresponding to the negative pressure value of the first cylinder 31;
b) configuring the electronic control unit 241 to determine a first time point where the negative pressure signal has reached a predetermined maximum value L, to determine a second time point where the crankshaft position sensor 38 detects a predetermined crankshaft angle P, and to determine a crankshaft angular distance travelled between the first and second time points;
c) when the crankshaft angular distance is within a predetermined angular distance (in this embodiment, the predetermined angular distance is 60 degrees), configuring the electronic control unit 241 to perform control for ignition and fuel injection in the first cylinder 31 once every two cycles of crankshaft rotation, in which a first amount of fuel is injected during the fuel injection; and
d) when the crankshaft angular distance is not within the predetermined angular distance, configuring the electronic control unit 241 to perform control for ignition and fuel injection in the first cylinder 31 once every cycle of crankshaft rotation, in which a second amount of fuel is injected during the fuel injection.

In this embodiment, the second amount of fuel is one-half of the first amount of fuel.
Preferably, in step c), a timing of ignition occurs a predetermined time period after one cycle of crankshaft rotation during which the negative pressure signal has reached the predetermined maximum value L, and a timing of fuel injection occurs after one cycle of crankshaft rotation during which the negative pressure signal does not reach the predetermined maximum value L.
The first preferred embodiment of the method is illustrated by taking operation of the first cylinder 31 as an example. In practice, while the electromagnetic switch 231 is controlled to switch between the first and second switch states as illustrated respectively in Figure 4 and Figure 5, the pressure sensor 221 may determine the respective negative pressure value of a selected one of the first and second cylinders 31, 32, and may generate the negative pressure signal corresponding to the negative pressure value of the selected one of the first and second cylinders 31, 32 for ignition and fuel injection control of the selected one of the first and second cylinders 31, 32. Since operation for detecting the second cylinder 32 is similar to that for detecting the first cylinder 31, further details are omitted herein for the sake of brevity.
Since the electronic control unit 241 is configured to control the electromagnetic switch 231 to switch between the first and second switch states such that the pressure sensor 221 may generate the negative pressure signal corresponding to the negative pressure value of the selected one of the first and second cylinders 31, 32, the electronic control unit 241 is configured to perform control for ignition, which has the timing of ignition that occurs the predetermined time period after one cycle of crankshaft rotation during which the negative pressure signal has reached the predetermined maximum value L, with reference to the crankshaft rotation signal and the negative pressure value of the selected one of the first and second cylinders 31, 32 so as to raise precision of injection timing and durability of cylinders, and so as to reduce pollution resulting from incomplete combustion.
Referring to Figures 3 to 5, if one of the first and second cylinders 31, 32 has an abnormal situation or carbon deposit, the electronic control device 241 may be configured to control the electromagnetic switch 231 to switch to one of the first and second switch states so as to determine the negative pressure value of the selected one of the first and second cylinders 31, 32 such that determination as to which one of the first and second cylinders 31, 32 has the abnormal situation or carbon deposit may be made quickly. In this way, maintenance speed and accuracy are improved.
Referring to Figure 7, a second preferred embodiment of the device 2 for controlling operation of the injection engine 3 according to the present invention is illustrated. The second preferred embodiment of the device 2 is substantially similar to the first preferred embodiment. This embodiment differs from the previous embodiment in the configuration that the electronic control unit 241 is configured to control the electromagnetic switch 231 to further switch to a third switch state, in which the first and second sampling conduits 211, 212 are unblocked as illustrated in Figure 7. In this embodiment, the electromagnetic switch 231 is a continuous electromagnetic valve.
A second preferred embodiment of a method for controlling operation of the injection engine 3 is performed using the second preferred embodiment of the device 2 mentioned above. Aside from the effect achieved in the first preferred embodiment of the method of the present invention, when the first and second cylinders 31, 32 operate normally, the electronic control unit 241 is further configured to control the electromagnetic switch 231 to switch to the third switch state as illustrated in Figure 7 such that the pressure sensor 221 may determine a combined negative pressure value as illustrated by arrows 41, 42 in Figure 7. In this way, switching frequency of the electromagnetic switch 231 may be reduced, and durability of the device 2 of the present invention may be improved.
In summary, the device 2 and method for controlling operation of the injection engine 3 use the electronic control unit 241, which is configured to control the electromagnetic switch 231 such that the pressure sensor 221 may generate the negative pressure signal corresponding to the negative pressure value of a selected one of the first and second cylinders 31, 32. The electronic control unit 241 is configured to perform control for ignition, which has the timing of ignition that occurs the predetermined time period after one cycle of crankshaft rotation during which the negative pressure signal has reached the predetermined maximum value L, with reference to the crankshaft rotation signal and the negative pressure value of the selected one of the first and second cylinders 31, 32 so as to improve precision of injection timing and durability of cylinders, and so as to reduce pollution resulting from incomplete combustion.

Claims

A method for controlling operation of an injection engine (3), the injection engine (3) including
first and second cylinders (31, 32),
a first sampling conduit (211) through which a negative pressure in the first cylinder (31) isacquired,
a second sampling conduit (212) through which a negative pressure in the second cylinder (32) is acquired,
a pressure sensor (221) coupled to the first and second sampling conduits (211, 212) and operable to sense pressure in the first and second sampling conduits (211, 212),
a crankshaft position sensor (38) for detecting crankshaft rotation of the injection engine (3) and generating a crankshaft rotation signal corresponding to the crankshaft rotation detected thereby, and
an electronic control unit (241) electrically coupled to the pressure sensor (221) and the crankshaft position sensor (38),
the method comprising:
a) configuring the electronic control unit (241) to control an electromagnetic switch (231), which is disposed to block and unblock fluid communication between the pressure sensor (221) and each of the first and second sampling conduits (211, 212), so that the pressure sensor (221) may determine a negative pressure value of a selected one of the first and second cylinders (31, 32) through a respective one of the first and second sampling conduits (211, 212) and may generate a negative pressure signal corresponding to the negative pressure value of the selected one of the first and second cylinders (31, 32);

b) configuring the electronic control unit (241) to determine a first time point where the negative pressure signal has reached a predetermined maximum value, to determine a second time point where the crankshaft position sensor (38) detects a predetermined crankshaft angle, and to determine a crankshaft angular distance travelled between the first and second time points;

c) when the crankshaft angular distance is within a predetermined angular distance, configuring the electronic control unit (241) to perform control for ignition and fuel injection in the selected one of the first and second cylinders (31, 32) once every two cycles of crankshaft rotation, in which a first amount of fuel is injected during the fuel injection; and

d) when the crankshaft angular distance is not within the predetermined angular distance, configuring the electronic control unit (241) to perform control for ignition and fuel injection in the selected one the first and second cylinders (31, 32) once every cycle of crankshaft rotation, in which a second amount of fuel is injected during the fuel injection.
The method as claimed in claim 1, characterized in that, in step c), a timing of ignition occurs a predetermined time period after one cycle of crankshaft rotation during which the negative pressure signal has reached the predetermined maximum value, and a timing of fuel injection occurs after one cycle of crankshaft rotation during which the negative pressure signal does not reach the predetermined maximum value.
The method as claimed in claims 1 or 2, characterized in that the second amount of fuel is smaller than the first amount of fuel.
The method as claimed in any one of claims 1 to 3, characterized in that, in step a), the electronic control unit (241) is configured to control the electromagnetic switch (231) to switch periodically between a first switch state, in which the second sampling conduit (212) is blocked and the first sampling conduit (211) is unblocked, and a second switch state, in which the first samplingconduit (211) is blocked and the second sampling conduit (212) is unblocked.
The method as claimed in any one of claims 1 to 4, characterized in that the electromagnetic switch (231) is a two-way electromagnetic valve.
The method as claimed in any one of claims 1 to 3, characterized in that, in step a), the electronic control unit (241) is configured to control the electromagnetic switch (231) to switch among a first switch state, in which the second sampling conduit (212) is blocked and the first sampling conduit (211) is unblocked, a second switch state, in which the first sampling conduit (211) is blocked and the second sampling conduit (212) is unblocked, and a third switch state, in which the first and second sampling conduits (211, 212) are unblocked.
The method as claimed in any one of claims 1, 2, 3 and 6, characterized in that the electromagnetic switch (231) is a continuous electromagnetic valve.
A device (2) for controlling operation of an injection engine (3), the injection engine (3) including first and second cylinders (31, 32) and a crankshaft position sensor (38) for detecting crankshaft rotation of the injection engine (3) and generating a crankshaft rotation signal corresponding to the crankshaft rotation detected thereby, the device (2) comprising:
a first sampling conduit (211) through which a negative pressure in the first cylinder (31) is acquired;

a second sampling conduit (212) through which a negative pressure in the second cylinder (32) is acquired;

a pressure sensor (221) coupled to the first and secondsamplingconduits (211, 212) and operable to sense pressure in the first and second sampling conduits (211, 212);

an electromagnetic switch (231) disposed to block and unblock fluid communication between the pressure sensor (221) and each of the first and second sampling conduits (211, 212); and

an electronic control unit (241) electrically coupled to the pressure sensor (221) and the electromagnetic switch (231) and disposed to receive the crankshaft rotation signal;

wherein the electronic control unit (241) is configured to control the electromagnetic switch (231) so that the pressure sensor (221) may determine a negative pressure value of a selected one of the first and second cylinders (31, 32) through a respective one of the first and second sampling conduits (211, 212), and is configured to perform control for ignition and fuel injection in the selected one of the first and second cylinders (31, 32) with reference to the crankshaft rotation signal and the negative pressure value of the selected one of the first and second cylinders (31, 32).
The device (2) as claimed in claim 8, characterized in that the electronic control unit (241) is configured to control the electromagnetic switch (231) to switch periodically between a first switch state, in which the second sampling conduit (212) is blocked and the first sampling conduit (211) is unblocked, and a second switch state, in which the first sampling conduit (211) is blocked and the second sampling conduit (212) is unblocked.
The device (2) as claimed in claim 8, characterized in that the electronic control unit (241) is configured to control the electromagnetic switch (231) to switch among a first switch state, in which the second sampling conduit (212) is blocked and the first sampling conduit (211) is unblocked, a second switch state, in which the first sampling conduit (211) is blocked and the second sampling conduit (212) is unblocked, and a third switch state, in which the first and second sampling conduits (211, 212) are unblocked.
The device (2) as claimed in any one of claims 8 to 10, the injection engine (3) further including a first throttle body (33) coupled to the first cylinder (31), and a second throttle body (34) coupled to the second cylinder (32), the first cylinder (31) including a first intake valve (311), the second cylinder (32) including a second intake valve (321), characterized in that the first sampling conduit (211) has one end coupled to the electromagnetic switch (231), and another end coupled between the first throttle body (33) and the first intake valve (311) of the first cylinder (31), and the second sampling conduit (212) has one end coupled to the electromagnetic switch (231), and another end coupled between the second throttle body (34) and the second intake valve (321) of the second cylinder (32).
The device (2) as claimed in claims 8 or 9, characterized in that the electromagnetic switch (231) is a two-way electromagnetic valve.
The device (2) as claimed in claims 8 or 10, characterized in that the electromagnetic switch (231) is a continuous electromagnetic valve.
The device (2) as claimed in any one of claims 8 to 13, further comprising a transmission conduit (222) coupled between the electromagnetic switch (231) and the pressure sensor (221).
The device (2) as claimed in any one of claims 8 to 14, characterized in that the electronic control unit (241) is configured
to generate a negative pressure signal corresponding to the negative pressure value of the selected one of the first and second cylinders (31, 32),
to determine a first time point where the negative pressure signal has reached a predetermined maximum value, to determine a second time point where the crankshaft rotation signal indicates detection of a predetermined crankshaft angle, and to determine a crankshaft angular distance travelled between the first and second time points,
when the crankshaft angular distance is within a predetermined angular distance, to perform control for ignition and fuel injection in the selected one of the first and second cylinders (31, 32) once every two cycles of crankshaft rotation, in which a first amount of fuel is injected during the fuel injection; and
when the crankshaft angular distance is not within the predetermined angular distance, to perform control for ignition and fuel injection in the selected one of the first and second cylinders (31, 32) once every cycle of crankshaft rotation, in which a second amount of fuel is injected during the fuel injection.