Field of the invention
[001] This invention relates to the field of internal combustion (IC) engines. The
invention proposes improvements for pressurizing the air in the IC engines
Background of the invention
[002] Internal Combustion engines pressurize air using different techniques, before the air is delivered to the combustion chamber. These include super chargers, turbo chargers etc.
[003] The patent US 3,973,532 discloses an engine. The engine comprises a reciprocating-piston which includes a sealed crankcase for inducting and compressing air or an air-fuel mixture into the engine. The compressed gas is then forced into a holding tank for subsequent induction into the cylinder combustion chamber. This pre-compresses or "supercharges" the fuel mixture before compression by the piston.
Brief description of the accompanying drawing
[004] Different modes of the invention are disclosed in detail in the description and
illustrated in the accompanying drawing:
[0005] FIG. 1 illustrates an IC engine according to one embodiment of the invention.
Detailed description of the embodiments
[006] FIG. 1 shows an internal combustion engine 100 according to one embodiment of the invention. The internal combustion engine 100 is referred as IC engine or just

as an engine in this document. In the figure and the description, only the important parts are described. Commonly known parts are not described.
[007] The engine 100 comprises a cylinder 102, a crank case 104, a piston 106, a combustion chamber 108, a piston rod 110, a crank shaft 112, an intake valve 114, an exhaust valve 116, an intake manifold 118, a supercharger 120, an intercooler 122, a passage 123, an oil separator 124, a first valve 126 and a second valve 128. Here, only the important components are shown in the figure 1 and described.
[008] In the prior arts, the air enters through the intake manifold 118, flows into the cylinder 102 through the inlet valve 114 during the suction stroke of the engine 100. During the compression stroke of the engine 100, the air is compressed and fuel is injected where the air fuel mixture burns in the combustion chamber 108. The optional supercharger 120 which is driven by the engine 100, provides additional air to the engine 100. In addition, there may be a turbo charger which is not shown, providing pressurized air to the intake manifold 118.
[009] The piston 106 moves reciprocally in the cylinder 102. The position where the piston 106 pressurizes the air in the cylinder to the maximum, is referred as Top Dead Centre (TDC). The position where the piston 106 is at the farthest point from TDC is referred as Bottom Dead Centre (BDC). During the suction stroke where the piston 106 moves from TDC to BDC, the inlet valve 114 opens, exhaust valve 116 closes, the air is sucked into the cylinder 102. When the piston 106 starts moving from BDC to TDC during the compression stroke, the air in the cylinder 102 is pressurized as the intake valve 114 and exhaust valve 116 are closed. When the piston 106 is about to reach TDC, the fuel is injected into the combustion chamber 108 and the air fuel mixture ignites, thereby generating power and the piston 106 starts moving towards

BDC. Once the BDC is reached, the piston starts moving again towards TDC and the exhaust valve 116 is opened thereby sending the exhaust gases out of the engine 100.
[010] In the diesel engines, to generate more power, more air needs to be pushed into the cylinder. For this purpose the super charger and turbo chargers are used.
[011] The invention proposes improvements in the engine 100 to use the piston 106 to pressurize the air in the crank case 104 when the piston 106 is moving from TDC to BDC.
[012] The engine shown in fig. 1, according to the invention, comprises a passage 123 from the crank case 104 to the intake manifold 118. The passage 123 comprises the oil filter 124 and the first valve 126. There is the second valve 128 in the crank case 104. The second valve 128 when open, connects the volume in the crank case 104 with the atmosphere.
[013] When the piston 106 starts moving from BDC to TDC, the second valve 128 opens, thereby allowing the air from the atmosphere to enter into the crank case 104. During this time the first valve 126 is closed. When the piston starts moving from TDC to BDC, the second valve 128 closes and the first valve 126 opens. The piston 106 moving towards the BDC, pressurizes the air in the crank case 104 and the pressurized air passes through the oil separator 124 and then into the intake manifold 118 through the first valve 126. Thus the movement of the piston 106 is utilized to deliver pressurized air into the intake manifold 118.
[014] In one ignition cycle, the piston moves twice from TDC to BDC. Hence the piston 104 pressurizes and pressurized air is delivered to the combustion chamber 108 twice in one ignition cycle.

[015] There is the oil separator 124 provided in the passage 123. This is necessary to remove any oil from the air in the crank case 104. As there are moving parts like piston 106, crank shaft 112, piston rod 110 etc., in the engine, these need to be lubricated. Because of the lubrication and the movement of the parts of the engine 100, an oil fog is formed in the crank case 104 and this oil needs to be separated from the air before the air is sent to intake manifold 118. The oil separator 124 separates this oil and sends back the oil to the crank case 104 through the oil pipe 130.
[016] The first and second valves 126, 128 are unidirectional valves and allow air to flow in only one direction. The first valve 126 allows the air to flow from crank case 104 towards the intake manifold 118. The second valve 128 allows air to flow form atmosphere into the crank case 104. These valves block air from flowing in reverse direction.
[017] Optional supercharger 120 and intercooler 122 are provided in the engine 100. The supercharger 120 pressurizes the air further before delivering the air to the combustion chamber 108. The intercooler 122 cools the air passing through it and makes the air dense so that more air can be pushed into the combustion chamber 108.
[018] The invention proposes an internal combustion engine 100 comprising: a cylinder (102) having intake valve (114) and exhaust valve(116); a piston (106) reciprocally moving in the cylinder (102), the piston (06) reaching top dead center inside cylinder (102) while moving in a first direction, the piston (106) reaching bottom dead center inside cylinder (102) while moving in a second direction; a crankcase (104) disposed adjacent to the cylinder (102); a crankshaft (112) mounted in the crankcase (104), the crankshaft (112) connected to the piston (106) by a piston rod (110), the piston rod (110) converting reciprocal movement of the piston (106)

into rotary motion of crankshaft (112), the IC engine (100) characterized by :a passage (123) from crankcase (104) to the intake manifold (118) to pressurize air when said piston (106) is moving towards BDC; a second valve (128) in said crankcase (104) to allow fresh air into said crankcase (104) when the piston (106) is moving towards TDC.
[019] The invention proposes improvements in the engine100 to deliver more air to the cylinder 102. The movement of the piston 106 is made use of to pressurize the air before delivering it to the cylinders. The invention proposes simple passage 123 and valves 126, 128 to achieve the objective. For the given engine capacity, more air is delivered to the cylinders so that more power is generated by the engine.
.

1. An internal combustion engine (IC) 100 comprising:
- a cylinder (102) having intake valve (114) and exhaust valve(116)
- a piston (106) reciprocally moving in said cylinder (102), said piston (106) reaching top dead center inside cylinder (102) while moving in a first direction, said piston (106) reaching bottom dead center inside cylinder (102) while moving in a second direction
- a crankcase (104) disposed adjacent to said cylinder (102)
- a crankshaft (112) mounted in said crankcase (104), said crankshaft (112) connected to said piston (106) by a piston rod (110), said piston rod (110) converting reciprocal movement of said piston (106) into rotary motion of crankshaft (112)
said IC engine (100) characterized by:
- a passage (123) from crankcase to said intake manifold (118) to pressurize air when said piston (106) is moving towards BDC
- a second valve (128) in said crankcase (104) to allow fresh air into said crankcase (104) when the piston (106) is moving towards TDC

2. An IC engine (100) according to claim 1, wherein an oil separator (124) is disposed in said passage (123) to separate oil from air
3. An IC engine (100) according to claim 1, wherein a pipe (130) carries oil from said oil separator (124) to said crank case (104)
4. An IC engine (100) according to claim 1, wherein a first valve (126) in said passage (123) controls flow of air from crank case to said intake manifold (118)

5. An IC engine (100) according to claim 1, wherein said second valve (128) opens when said piston (106) moves from BDC to TDC
6. An IC engine (100) according to claim 1, wherein said first valve (126) opens when said piston (106) moves from TDC to BDC