Field of the invention:
[0001] The present invention relates to an air flow arrangement for an engine of a vehicle and a controller to control the air flow.
Background of the invention:
[0002] According to a patent literature, US20090171551, a secondary air supply system and vehicle is disclosed. The secondary air supply system includes a CPU, a first air supply pipe, a second air supply pipe, a first shut-off valve, and a second shut-off valve. First ends of the first air supply pipe and the second air supply pipe are connected to an air cleaner box and the other ends thereof are connected to an exhaust port. The CPU controls opening/closing of the first shut-off valve and the second shut-off valve based on a state of an engine. The first shut-off valve and the second shut-off valve are selectively opened by the CPU, so that air in the air cleaner box is supplied to the exhaust port through the first air supply pipe and/or the second air supply pipe.
Brief description of the accompanying drawings:
[0003] An embodiment of the disclosure is described with reference to the following accompanying drawing,
[0004] Fig. 1 illustrates an air flow arrangement for an engine of a vehicle, according to an embodiment of the present invention.
Detailed description of the embodiments:
[0005] Fig. 1 illustrates an air flow arrangement for an engine of a vehicle, according to an embodiment of the present invention. The air flow arrangement 100 comprises an intake conduit 102 having a throttle valve 104. The air flow arrangement 100 is characterized by, an air path 110 branching from the intake conduit 102. The air path 110 is divided into a first path 114 and connected to the intake conduit 102 after the throttle valve 104, and a second path 118 connected to an exhaust conduit 108 of the engine 106. The arrow at the intake conduit 102

represents inflow of air towards the engine 106 and the arrow at the exhaust conduit 108 represents outflow of exhaust gases from the engine 106.
[0006] The first path 114 is for supplying idle air to the engine 106 and the second path 118 is to supply secondary air to the exhaust gases. A control valve 112 is positioned in the air path 110 to control flow of air through the first path 114 and the second path 118. In one embodiment, the control valve 112 is a solenoid valve.
[0007] The control valve 112 is electrically controlled by a controller 120. The controller 120 is adapted to detect any one of an intake stroke and an exhaust stroke of the engine 106 based on a signal from a crankshaft position sensor 116, and actuate the control valve 112 based on the detected stroke to allow air to pass to any one of the first path 114 and the second path 118.
[0008] In accordance to an embodiment of the present invention, a first one-way valve 122 and a second one-way valve 124, are positioned in the first path 114 and said second path 118, respectively. In another embodiment, the first one-way valve 122 is provided at the interface 126 of the first path 114 and the intake conduit 102 after the throttle valve 104, and the second one-way valve 124 is provided at the interface 128 of the second path 118 and the exhaust conduit 108.
[0009] In accordance to another embodiment of the present invention, the control valve 112 is a mechanical valve. In which case, the control valve 112 is opened to a desired position and set by an operator such as a driver. The first one-way valve 122 and the second one-way valve 124 operate based on the pressure differential.
[0010] In accordance to yet another embodiment of the present invention, an air flow controller 120 (or the controller 120) is provided for the engine 106 of the vehicle. The vehicle comprises the intake conduit 102 having the throttle valve 104. The air path 110 is branched from the intake conduit 102 and is further branched/divided into the first path 114 and connected to the intake conduit 102

after the throttle valve 104, and the second path 118 is connected to the exhaust conduit 108 of the engine 106. A control valve 112 such as but not limited to a solenoid valve is positioned in the air path 110. The controller 120 is adapted to detect any one of the intake stroke and the exhaust stroke based on the signal from the crankshaft position sensor 116, and actuate the control valve 112 based on the detected stroke to allow air to pass to any one of the first path 114 and the second path 118. The crankshaft position sensor 116 is just a representation and is usually a trigger wheel based sensor.
[0011] According to the present invention, a working of the air flow arrangement 100 is described. The first one-way valve 122 and the second one-way valve 124 are mechanical valves and operated solely based on the pressure differences. However, electronically controlled valves are usable in synchronization with the control valve 112 to allow passage of air through the first path 114 and the second path 118. The controller 120 opens the control valve 112 when the intake stroke is detected using a signal from the crankshaft position sensor 116. The opening of the control valve 112 can also be further controlled based on engine speed, such as at low or idle engine speeds only. At intake stroke, there is a suction pressure created in a cylinder of the engine 106. However, there is ambient pressure at the inlet of the air path 110, which is higher than the suction pressure. Because of this pressure differential, the first one-way valve 122 is opened and the air flows into the cylinder of the engine 106. However, at the same time the pressure at the exhaust is high enough that the second one-way valve 124 remains closed. The air flowing through the first path 114 is the idle air.
[0012] Similarly, when the exhaust stroke is detected by the controller 120 using the crankshaft position sensor 116, the controller 120 opens the control valve 112. The air in the intake conduit 102 is at ambient pressure and the pressure at the exhaust is lower relative to the intake conduit 102. Due to pressure differential, the air flows through the second path 118 into the exhaust conduit 108. However, at the same time, the pressure at the intake conduit 102 after the throttle valve 104 is high

enough to keep the first one-way valve 122 in closed position. Thus, the air flows through the single path at a time.
[0013] In case of overlap of the low pressure regions in the intake conduit 102 and the exhaust conduit 108 at the same time, the air simultaneously flows through both the first path 114 and the second path 118.
[0014] According to an embodiment of the present invention, usage of a single control valve 112 for controlling idle air and secondary air is envisaged. The present invention enables the vehicle to start at lower temperatures and reduces emissions without increasing cost. An idle air is required to provide additional air into the intake manifold/conduit 102 to enable the vehicle to start and secondary air injection reduces Hydro Carbon (HC) emissions in cold phase. The single control valve 112 is used for meeting both the requirements. The idle air is required during intake stroke and during lower engine loads. The secondary air injection is required during exhaust strokes and will be used in lower to medium loads. During operation at common load points, the control valve 112 is switched and is scheduled corresponding to intake and exhaust strokes. The present invention is usable as a retrofit solution.
[0015] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.

We claim:
1. An air flow arrangement (100) for an engine (106) of a vehicle, comprising
an intake conduit (102) having a throttle valve (104), characterized in that
an air path (110) branching from said intake conduit (102), said air path (110) divided into a first path (114) connected to said intake conduit (102) after said throttle valve (104) and a second path (118) connected to an exhaust conduit (108) of said engine (106).
2. The air flow arrangement (100) as claimed in claim 1, wherein said first path (114) is an idle air path and said second path (118) is a secondary air path.
3. The air flow arrangement (100) as claimed in claim 1, wherein a control valve (112) is positioned in said air path (110) to control flow of air through said first path (114) and said second path (118).
4. The air flow arrangement (100) as claimed in claim 3, wherein said control valve (112) is a solenoid valve.
5. The air flow arrangement (100) as claimed in claim 3, wherein said control valve (112) is electrically controlled by a controller (120).
6. The air flow arrangement (100) as claimed in claim 5, wherein said controller (120) is adapted to:
detect any one of an intake stroke and an exhaust stroke based on a
signal from a crankshaft position sensor (116), and
actuate said control valve (112) based on the detected stroke to allow
air to pass to any one of said first path (114) and said second path
(118).

7. The air flow arrangement (100) as claimed in claim 3, wherein said control valve (112) is a mechanical valve.
8. The air flow arrangement (100) as claimed in claim 1, wherein a one-way valve (122, 124) is positioned in each of said first path (114) and said second path (118).
9. The air flow arrangement (100) as claimed in claim 8, wherein a first one-way valve (122) is provided at an interface (126) of said first path (114) and said intake conduit (102), and a second one-way valve (124) is provided at an interface (128) of said second path (118) and said exhaust conduit (108).
10. An air flow controller (120) for an engine (106) of a vehicle, said vehicle comprising an intake conduit (102) having a throttle valve (104), an air path (110) from said intake conduit (102) is divided into a first path (114) connected to said intake conduit (102) after said throttle valve (104) and a second path (118) connected to an exhaust conduit (108) of said engine (106), a control valve (112) is positioned in said air path (110), said controller (120) adapted to:
detect any one of an intake stroke and an exhaust stroke based on a
signal from a crankshaft position sensor (116), and
actuate said control valve (112) based on the detected stroke to allow
air to pass to any one of said first path (114) and said second path
(118).