FIELD 5 OF INVENTION:
[001] The present subject matter described herein, relates to an engine control system
installed in a vehicle, more particularly to a cylinder position and phase detection system
for an internal combustion engine of the vehicle.
BACKGROUND AND PRIOR ART:
10 [002] In Conventional IC engines, combination of cam sensor and crank sensor assist to
detect a unique pattern, with an idea to detect the piston position and trigger the injection
and ignition of fuel. Further, in current systems, at least two sensors are preferred for
cylinder phase identification i.e. cam sensor or crank sensor or MAP sensor etc. The input
from the crank sensor, and cam or MAP sensor are provided to a control unit for
15 identification of piston position and phase.
[003] Presently, since the cylinder position and phase identification is based on the
various logics before enabling the injection, ignition, an advanced software system, and
an associated hardware system is required, which must involve capabilities to identify
with great precision and accuracy the desired objective. However, such systems are
20 complex and cost intensive.
[004] United States Patent publication US7082362B2 discloses a cylinder identification
system. The cylinder identification device has an intake cam sensor and an exhaust cam
sensor which output signals indicative of a rotation angle of the camshaft. The levels of
the output signals are varied according to the rotation angle of the crankshaft. The
25 cylinder identification is conducted based on an order of combination variation of the
output signal levels. The changing positions of the output signal levels of at least one of
the intake cam sensor and the exhaust cam sensor are arranged in such a manner to
correspond to positions or right before positions in which the fuel can be initially injected
at the time of the engine starting. Thus, the cylinder identification device can identify the
30 initial cylinder in a short period, into which the fuel is initially injected at the time of the
engine starting, whereby the performance of start ability of the engine is enhanced.
3
[005] The US prior art provides multiple cam sensors provided at input and output for
cylinder identification. However, incorporation of multiple sensors and other electrical
components makes the system complex and expensive.
OBJECTS OF THE INVENTION:
[006] The principal objective of the present invention is to provide 5 an independent cam
sensor system for cylinder position and phase identification in vehicular engines to
overcome the deficiencies of the prior art.
[007] Another object of the present subject matter is to provide a simple, cost effective,
and efficient design to the cylinder position and phase identification system.
10 SUMMARY OF THE INVENTION:
[008] The present invention relates to a independent cam sensor system for cylinder
identification and phase detection in an internal combustion engine. The system including
a cam rotor that rotates in confirmation with a crankshaft of the internal combustion
engine, the cam rotor including a plurality of teeth portions (A, B, C) separated by a
15 plurality of gaps (G1, G2, G3) on a circumference of the cam rotor, wherein each of the
plurality of teeth portions (A, B, C) include at least one predefined unequal number of
teeth. The system further includes a cam sensor coupled to the cam rotor, the cam sensor
being configured to generate a plurality of output signals based on the plurality of teeth
portions (A, B, C) and the plurality of gaps (G1, G2, G3). The system also includes an
20 engine control unit (ECU) coupled to the cam sensor, wherein the ECU is configured for
receiving the plurality of output signals, and performing the cylinder identification and
phase detection based on the plurality of output signals.
[009] In order to further understand the characteristics and technical contents of the
present subject matter, a description relating thereto will be made with reference to the
25 accompanying drawings. However, the drawings are illustrative only but not used to limit
scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] It is to be noted, however, that the appended drawings illustrate only typical
embodiments of the present subject matter and are therefore not to be considered for
30 limiting of its scope, for the invention may admit to other equally effective embodiments.
The detailed description is described with reference to the accompanying figures. In the
4
figures, the left-most digit(s) of a reference number identifies the figure in which the
reference number first appears. The same numbers are used throughout the figures to
reference like features and components. Some embodiments of system or methods in
accordance with embodiments of the present subject matter are now described, by way of
example, and with reference to the accompanying 5 figures, in which:
[0011] Fig. 1 illustrates a diagram showing a schematic structure of a independent cam
sensor system according to an embodiment of the present invention;
[0012] Fig. 2 illustrates components of conventional engine phase detection system;
[0013] Fig. 3 illustrates a schematic diagram of the cam rotor configured with the cam
10 sensor of the system of Fig. 1 according to an embodiment of the present disclosure;
[0014] Fig. 4 illustrates the electronic control unit (ECU) of the system of Fig. 1 in
accordance with an embodiment of the present disclosure;
[0015] Fig. 5 illustrates the output signal i.e. a cam signal pattern detected by the cam
sensor, and is input to the ECU; and
15 [0016] Figs. 6a-6c illustrates identified piston positions in accordance with an
embodiment of the present disclosure.
[0017] The figures depict embodiments of the present subject matter for the purposes of
illustration only. A person skilled in the art will easily recognize from the following
description that alternative embodiments of the structures and methods illustrated herein
20 may be employed without departing from the principles of the disclosure described
herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0018] The present disclosure presents embodiments for a independent cam sensor
system for cylinder identification and phase detection in an internal combustion engine.
25 The system including a cam rotor that rotates in confirmation with a crankshaft of the
internal combustion engine, the cam rotor including a plurality of teeth portions (A, B, C)
separated by a plurality of gaps (G1, G2, G3) on a circumference of the cam rotor,
wherein each of the plurality of teeth portions (A, B, C) include at least one predefined
unequal number of teeth. The system further includes a cam sensor coupled to the cam
30 rotor, the cam sensor being configured to generate a plurality of output signals based on
the plurality of teeth portions (A, B, C) and the plurality of gaps (G1, G2, G3). The
5
system also includes an engine control unit (ECU) coupled to the cam sensor, wherein the
ECU is configured for receiving the plurality of output signals, and performing the
cylinder identification and phase detection based on the plurality of output signals.
[0019] It should be noted that the description and figures merely illustrate the principles
of the present subject matter. It should be appreciated by those skilled 5 in the art that
conception and specific embodiment disclosed may be readily utilized as a basis for
modifying or designing other structures for carrying out the same purposes of the present
subject matter. It should also be appreciated by those skilled in the art that by devising
various arrangements that, although not explicitly described or shown herein, embody the
10 principles of the present subject matter and are included within its spirit and scope.
Furthermore, all examples recited herein are principally intended expressly to be for
pedagogical purposes to aid the reader in understanding the principles of the present
subject matter and the concepts contributed by the inventor(s) to furthering the art, and
are to be construed as being without limitation to such specifically recited examples and
15 conditions. The novel features which are believed to be characteristic of the present
subject matter, both as to its organization and method of operation, together with further
objects and advantages will be better understood from the following description when
considered in connection with the accompanying figures.
[0020] These and other advantages of the present subject matter would be described in
20 greater detail with reference to the following figures. It should be noted that the
description merely illustrates the principles of the present subject matter. It will thus be
appreciated that those skilled in the art will be able to devise various arrangements that,
although not explicitly described herein, embody the principles of the present subject
matter and are included within its scope.
25 [0021] Fig. 1 is a diagram showing a schematic structure of a independent cam sensor
system 100, hereinafter referred to as system 100 according to an embodiment of the
present invention. As illustrated, the system 100 includes an internal combustion engine
102, an intake pipe 104, an injector 106, an exhaust pipe 108, a spark plug 110, a cam
rotor 112, a cam shaft 114, a cam sensor 116, and an electronic control unit 118,
30 hereinafter referred to as ECU 118. The system 100 of FIG. 1 can be implemented for n
number of cylinder internal combustion engines. In an embodiment, the system 100
includes only the cam sensor 116 for position and phase identification of a cylinder of the
internal combustion engine 102. A crank sensor is not provided in the system 100.
6
[0022] Fig. 2 illustrates components of conventional engine phase detection systems. As
shown, the prior art systems include a crank sensor 202 configured with a crank rotor
204, and a cam sensor 206 configured with a cam rotor 208. The prior art systems were
dependent upon input from both the crank sensor 202 and the cam sensor 206 for phase
and position detection of 5 engine cylinders.
[0023] Fig. 3 illustrates a schematic diagram of the cam rotor 112 configured with the
cam sensor 116 of the system 100 of Fig. 1 according to an embodiment of the present
disclosure. In an embodiment, the cam rotor 112 rotates in synchronous with a crankshaft
(not shown) of the internal combustion engine 102. Further, the cam rotor 112 includes a
10 plurality of teeth portions, i.e. Portion A, Portion B, Portion C on a circumference of the
cam rotor 112. In an embodiment, the plurality of teeth portions A, B, and C includes a
predefined number of teeth. In an example, Portion A includes two (2) teeth, Portion B
includes four (4) teeth, and Portion C includes three (3) teeth. Alternatively, the plurality
of teeth portions may include any not equal number of teeth. Further, the plurality of teeth
15 portions A, B, and C are separated by a plurality of gaps G1, G2, and G3 respectively.
The plurality of gaps G1, G2, and G3 include no teeth.
[0024] Further, the cam sensor 116 as configured with the cam rotor 112 is configured to
sense, evaluate, and identify the plurality of teeth portions A, B, and C and the plurality
of gaps G1, G2, and G3 on the cam rotor 112, and consecutively identify the plurality of
20 teeth portions A, B, and C and the plurality of gaps G1, G2, and G3 as the cam rotor 112
rotates. In an embodiment, the cam sensor 116 is further configured for a sequential
identification of the plurality of teeth portions A, B, and C and the plurality of gaps G1,
G2, and G3, wherein the sequential identification depends upon a rotation of the cam
rotor 112 in a clockwise or counter-clockwise direction. The cam sensor 116 is further
25 configured to generate a plurality of output signals, wherein each signal of the plurality of
output signals is corresponding to the identification of the plurality of teeth portions A, B,
and C, the plurality of gaps G1, G2, and G3, and the sequential identification mentioned
above.
[0025] In an embodiment, one revolution of the cam rotor 112 defines a cam angle (CA)
30 of 360 degrees. Further, the plurality of teeth portions A, B, and C, and the plurality of
gap portions G1, G2, and G3 may be provided at certain predefined CA angle / degree in
360 degrees of CA. For example, the teeth portion A may be provided at ANG0 degrees
CA, followed by the gap G1 at ANG1degrees CA, followed by the teeth portion B at
7
ANG2 degrees CA, followed by the gap G2 at ANG3 degrees CA, followed by the teeth
portion C at ANG4 degrees CA, followed by the gap G3 at ANG5 degrees CA. In an
embodiment, a 360 degrees CA rotation for the cam rotor 112 will include the following
sequence in clockwise direction considering the teeth portion A as reference –
A>G1>B>G2>C>G3, and the following sequence in counter-5 clockwise direction
considering the teeth portion C as reference – C>G2>B>G1>A>G3. The aforementioned
angular orientations are exemplary.
[0026] Fig. 4 illustrates the ECU 118 of the system 100. With ref. to Fig. 1 and Fig. 4,
the ECU 118 is coupled with the injector 106, the spark plug 110, and the cam sensor
10 116. In an embodiment, the ECU 118 is configured to receive the plurality of output
signals from the cam sensor 116 as described above. Based on the received output signals
corresponding to the identification of the plurality of teeth portions A, B, and C, the
plurality of gaps G1, G2, and G3, and the sequential identification mentioned above, the
ECU 118 performs a phase detection and cylinder identification for the internal
15 combustion engine 102. Based on the phase detection and the cylinder identification, the
ECU 118 operates the injector 106 for supplying fuel to the internal combustion engine
102, and further operates the spark plug 110 for igniting the fuel in the internal
combustion engine 102.
[0027] Fig. 5 shows the output signal i.e. a cam signal pattern detected by the cam sensor
20 116, and is input to the ECU 118. The cam signal pattern is a signal output waveform of
the cam sensor 116 with respect to the plurality of teeth portions A, B, and C, and the
plurality of gaps G1, G2, and G3. Based on the cam signal pattern being received by the
ECU 118 and taking into account the angular orientations (CA angles) of the plurality of
teeth portions A, B and C, and the plurality of gaps G1, G2, and G3, the ECU 118
25 evaluates a cylinder position of the internal combustion engine 102, range of the cylinder
position lying between a top dead center (TDC) and a bottom dead center (BDC). For
instance, a cam pattern A>G1>B>G2 may correspond to a unique piston position X of
cylinder 1 (As shown in Fig. 6a), a cam pattern B>G2>C>G3 may correspond to a unique
piston position Y of cylinder 2 (As shown in Fig. 6b), and a cam pattern C>G3>A>G1
30 may correspond to a unique piston position Z of cylinder 3 (As shown in Fig. 6c), etc.
Based on the identified piston positions X, Y, or Z, of particular cylinder the ECU 118
performs the phase detection and cylinder identification for the internal combustion
engine 102. Hence, the new proposed independent cam sensor system 100 avoids
8
complexity and reduces the crank sensor dependency. In case of proposed system 100, the
cam sensor 116 independently will be able to detect the piston position by the assistance
of its unique design of the cam rotor 112. The cam rotor 112 design is robust enough to
detect piston position accurately.
[0028] In an embodiment, the ECU 118 is also configured to identify 5 a forward rotation
and reverse rotation of the engine 102. In an example as described earlier, the forward
rotation may correspond to 360 degrees CA rotation for the cam rotor 112 in the
clockwise direction considering the teeth portion A as reference – A>G1>B>G2>C>G3,
and the reverse rotation may be 360 degrees CA rotation for the cam rotor 112 in the
10 counter-clockwise direction considering the teeth portion C as reference –
C>G2>B>G1>A>G3. However, it is to be mentioned that the reverse rotation is an
undesirable event and may damage the internal combustion engine 102. Hence, the ECU
118 is configured to detect the reverse rotation, and after detection stop the fuel supply by
shutting the injector 106, and stop ignition of the spark plug 110 to prevent damage to the
15 internal combustion engine 102.
[0029] In another exemplary embodiment, the ECU 118 is also configured to calculate
the internal combustion engine 102 RPM and monitor misfire associated with the internal
combustion engine 102. The internal combustion engine 102 RPM is calculated by
evaluating change in angular speed of the cam rotor 112. In conventional IC engines,
20 speed of cam shaft is half of the speed of crank shaft. So, by evaluating the changing of
angular speed of the cam shaft 112 rotation, the cam shaft 112 RPM is calculated and
subsequently the crank shaft rotation speed and the internal combustion engine 102 RPM.
[0030] In an embodiment, to monitor the internal combustion engine 102 misfire, the
ECU 118 provides a feedback regarding a change in RPM beyond a predefined threshold
25 value, and the misfiring of the internal combustion engine 102 on a dashboard of the
vehicle, so as to make an occupant of the vehicle aware and take corrective action. In an
example, the feedback may be an analog, a digital, a tactile, audio, video, or the like
feedback.
[0031] Although embodiments for the present subject matter have been described in
30 language specific to structural features, it is to be understood that the present subject
matter is not necessarily limited to the specific features described. Rather, the specific
features and methods are disclosed as embodiments for the present subject matter.
9
Numerous modifications and adaptations of the system/component of the present
invention will be apparent to those skilled in the art, and thus it is intended by the
appended claims to cover all such modifications and adaptations which fall within the
scope of the present subject matter.
5
10
We claim:
1. An independent cam sensor system (100) for cylinder identification and phase
detection in an internal combustion engine (102), the system (100) comprising:
a cam rotor (112) that rotates in confirmation with a crankshaft of the
internal combustion engine (102), the cam rotor (112) including 5 a plurality of
teeth portions (A, B, C) separated by a plurality of gaps (G1, G2, G3) on a
circumference of the cam rotor (112), wherein each of the plurality of teeth
portions (A, B, C) include at least one predefined unequal number of teeth;
a cam sensor (116) coupled to the cam rotor (112), the cam sensor (116)
10 being configured to generate a plurality of output signals based on the plurality of
teeth portions (A, B, C) and the plurality of gaps (G1, G2, G3); and
an engine control unit (ECU) (118) coupled to the cam sensor (116),
wherein the ECU (118) is configured for receiving the plurality of output signals,
and performing the cylinder identification and phase detection based on the
15 plurality of output signals.
2. The independent cam sensor system (100) as claimed in claim 1, wherein the
plurality of teeth portions (A, B, C) include unequal number of teeth.
20 3. The independent cam sensor system (100) as claimed in claim 1, wherein the
plurality of output signals include identification of one of the plurality of teeth
portions (A, B, C), the plurality of gaps (G1, G2, G3), or a sequential
identification of the plurality of teeth portions (A, B, C) and the plurality of gaps
(G1, G2, G3).
25
4. The independent cam sensor system (100) as claimed in claim 1, wherein the
plurality of teeth portions (A, B, C) have unequal angular widths ANG0, ANG2,
and ANG4 respectively.
30 5. The independent cam sensor system (100) as claimed in claim 1, wherein the
plurality of gaps (G1, G2, G3) define angular widths ANG1, ANG3, and ANG5
respectively, wherein ANG1, ANG3, ANG5 can be equal or unequal.
11
6. The independent cam sensor system (100) as claimed in claim 3, wherein the
sequential identification depends upon a rotation of the cam rotor (112) in a
clockwise or counter-clockwise direction.
7. The independent cam sensor system (100) as claimed in claim 5 3, wherein the
plurality of output signals is a cam signal pattern, the cam signal pattern is a
signal output waveform of the cam sensor (116) with respect to the plurality of
teeth portions (A, B, C), and the plurality of gaps (G1, G2, G3).
10 8. The independent cam sensor system (100) as claimed in claim 1, wherein one
revolution of the cam rotor 112 defines a cam angle (CA) of 360 degrees, and the
plurality of teeth portions (A, B, C), and the plurality of gaps (G1, G2, G3) are
provided at predefined CA angle / degree in 360 degrees of the CA.
15 9. The independent cam sensor system (100) as claimed in claim 7, wherein the
ECU (118) is configured to identify a piston position (X, Y, Z) based on the
corresponding cam signal pattern (A>G1>B>G2, B>G2>C>G3, C>G3>A>G1).
10. The independent cam sensor system (100) as claimed in claim 1, wherein the
20 ECU (118) is coupled to an injector (106) and a spark plug (110), wherein the
ECU (118) operates the injector (106) for supplying fuel to the internal
combustion engine (102), and further operates the spark plug (110) for igniting
the fuel in the internal combustion engine (102) based on the phase detection and
the cylinder identification.
25 11. The independent cam sensor system (100) as claimed in claim 1, wherein the
ECU (118) is configured to identify a forward rotation and a reverse rotation of
the cam rotor (112), wherein the forward rotation correspond to 360 degrees CA
rotation for the cam rotor (112) in the clockwise direction considering the teeth
30 portion A as reference and having sequence – A>G1>B>G2>C>G3, and the
reverse rotation correspond to 360 degrees CA rotation for the cam rotor (112) in
the counter-clockwise direction considering the teeth portion C as reference and
having sequence – C>G2>B>G1>A>G3.
12
12. The independent cam sensor system (100) as claimed in claim 1, wherein the
ECU (118) is configured to monitor an RPM and misfire associated with the
internal combustion engine (102) based on the plurality of output signals of cam
rotor 112 and the identified cylinder position and phase detection.
5 13. The independent cam sensor system (100) as claimed in claim 12, wherein the
ECU (118) provides a feedback regarding a change in RPM beyond a predefined
threshold value, and the misfiring of the internal combustion engine (102) on a
dashboard of the vehicle, so as to make an occupant of the vehicle aware and take
10 corrective action.