CLIAMS:We claim:
1. An internal combustion engine (10) comprising:
at least one cylinder adapted to receive at least an air charge from an air charging device (12);
characterized in that
said internal combustion engine (10) adapted to receive an air charge from an air charging device (12) such that said air charge is in the range of 200-800mbar over the full engine speed range.
2. The internal combustion engine (10) as claimed in claim 1, wherein said air charging device (12) is a mechanical supercharger.
3. The internal combustion engine (10) as claimed in claim 1, wherein said internal combustion engine (10) is a 1 cylinder internal combustion engine.
4. The internal combustion engine (10) as claimed in claim 1, wherein said internal combustion engine (12) comprises at least two cylinders.
5. The internal combustion engine (10) as claimed in claim 1 or 4, wherein said internal combustion is a two cylinder engine.
6. A method of operating an internal combustion engine (10), said internal combustion engine (10) comprising an air intake path and an air charging device (12) located in said air intake path, said method comprising the following step:
receiving air charge from said air charge device (12) located in said air intake path;
characterized in that,
said internal combustion engine (10) adapted to receive air charge in the range of 200-800mbar over the full engine speed range.
7. The method as claimed in claim 6, wherein said air charge in the range of 200-800mbar is received in the full load operating condition of the internal combustion engine. ,TagSPECI:Field of the invention
[001] This disclosure relates to an internal combustion.

Background of the invention:
[002] Single cylinder engine are well known in the state of the art. However, single cylinder engines are primarily naturally aspirated. Naturally aspirated engine can be defined as engines wherein the air charge introduced into the engine is not pressurized by any external air charging devices such as superchargers or turbochargers or the like. Engines which have 3 or more cylinders use turbochargers for the purpose of charging the air that is introduced into the cylinders of these engines. However, using turbochargers do not provide the same advantages in single cylinder and two cylinder engines, since the exhaust flow rates in single and two cylinder engines is comparatively smaller. Further the flow rates in single and two cylinder engine keep fluctuating or pulsating based on the engine operation. These pulsating exhaust flow rates in a single and two cylinder reduce the efficiency of the turbocharger and thereby the overall efficiency of the engines. Even more critical from the point of view of engine operation is the smoke emissions. Particularly single and two cylinder engines are highly sensitive to smoke emission especially in full load. The power specification and the torque characteristics of these small engine leads to the usage of these engine near full load or in full load.

[003] Further, there is a need to provide a cost efficient manner in which higher lambda values can be obtained for such small capacity engines. In case of an emerging country like India, such higher lambda values are particularly required for positive certifications tests of BS3 and BS4 engines. Thus for such small capacity engines such as single cylinder and two cylinder engines, it is important that air charge is available any engine operating condition while the engine is being run in full load conditions.

[004] One such application for an internal combustion engine is disclosed in the patent document numbered EP151407. The patent document discloses a supercharged internal combustion engine. In accordance with the disclosure in this document the exhaust gases are used to drive the rotor of the supercharger. There is also provided a motor which is connected to the rotor which can also be used to drive the rotor. Thus based on engine operating condition the supercharger is either driven by the exhaust gases or motor. In particular under heavy load condition the motor is used to drive the supercharger since the exhaust air will not be sufficient enough to drive the supercharger to provide air charge required to drive the engine.

Brief description of the accompanying drawings:
[005] An embodiment of the disclosure is described with reference to the following accompanying drawings;
[006] Figure 1 illustrates a schematic layout of the internal combustion engine in accordance with this invention along with the other components of the air system of the internal combustion engine.

Detailed Description Of The Embodiments:
[007] Figure 1 illustrates a schematic layout of the internal combustion engine in accordance with this invention along with the other components of the air system of the internal combustion engine. The internal combustion engine 10 comprising: at least one cylinder adapted to receive at least an air charge from an air charging device 12. The internal combustion engine 10 is characterized such that the internal combustion engine 10 adapted to receive an air charge from an air charging device 12 such that the air charge is in the range of 200-800mbar over the full engine speed range. In accordance with this disclosure the air charging device 12 used in the air system of the internal combustion engine 10 is a mechanical supercharger.

[008] The schematic layout as shown in figure 1 can be explained as follows. The internal combustion engine 10 is a small capacity engine. For the purposes of better clarity of this disclosure we consider that the internal combustion engine is a single cylinder engine. The internal combustion engine 10 is provided with an air system. The air system comprises for two important air flow paths viz an air intake path and an exhaust air path. The air intake path is adapted to supply air from the atmosphere to the cylinder of the internal combustion engine 10. The exhaust air path is adapted to take the exhaust gases from the internal combustion engine and after processing the exhaust gases take them out of the air system. An air charging device 12 is located in the air intake path of the internal combustion engine. As mentioned earlier the air charging device 12 is a supercharger. The supercharger receives air and charges this air i.e increase the pressure of air and supplies this charged air to the cylinder of the engine. Another embodiment of the internal combustion engine in accordance with this disclosure is a two cylinder engine. The position or location of the various components of the air system would remain the same in a two cylinder engine. In accordance with another embodiment of the internal combustion engine the air system may also have an exhaust gas recirculation path. In such an embodiment the air charging device 12 i.e. the supercharger is located downstream of the part of the air intake where the exhaust gas is introduced back into the air intake.

[009] A method of operating an internal combustion engine 10 is also disclosed. The internal combustion engine 10 comprises an air intake path and an air charging device 12 located in the air intake path. The internal combustion engine 10 receives air charge from the air charge device 12 located in the air intake path. The method of operating the internal combustion engine is characterized such that the internal combustion engine 10 is adapted to receive air charge in the range of 200-800mbar over the full engine speed range. The air charge in the range of 200-800mbar is received in the full load, part load and low load operating condition of the internal combustion engine 10. The possibility of providing air intake charge in the range mentioned above is important as this allows for an optimum value of compression ratio within the single and two cylinder internal combustion engine. The compression ratio ensures higher robustness in emission legislations and consequently increase in power. Another advantage of being able to supply air charge in the range mentioned above is that a simple mechanical supercharger can be used without any additional requirement.

[0010] The supercharger 12 and the working of the supercharger 12 can be implemented in a number of ways. In accordance with one embodiment the supercharger implementation, the supercharger may be driven by the internal combustion itself. The supercharger may also have a bypass flap which can be either mechanically or electrically controlled to open or close so as to allow or disallow air charge from being sent to the internal combustion engine 12. In accordance with another embodiment of the supercharger implementation, the supercharger may be driven by the battery power of the vehicle. This implementation of the supercharger allows greater degree of freedom for supercharger operation, as the supercharger operation is now not dependent on the engine speed. This engine speed independent operation also allows that the supercharger need not be operated in part load operation thus saving energy.

[0011] 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.