Claims:We Claim:
1. An air assisting system (100) for an internal combustion engine (102), said air assisting system comprising:
- an air reservoir (108) to store air under pressure
- a vortex tube (110) connectable to said air reservoir (108) through a regulator (112) to receive pressurized air; said vortex tube 110 having a cold end (114) and a hot end (116); said cold end (114) supplying cold air and said hot end (116) supplying hot air to said engine (102); said cold end (114) connected to a first valve (118) to regulate amount of cold air being supplied to said engine (102); said hot end (116) connected to a second valve (120) to regulate amount of hot air being supplied to said engine (102)
- first by-pass path (122) connected to said first valve (118) to release excess cold air to atmosphere
- a second by-pass path (124) connected to said second valve (120) to release excess hot air to atmosphere
2. An air assisting system according to claim 1 wherein said air reservoir (108) receives compressed air from engine.
3. An air assisting system according to claim 1 wherein said regulator (122) controls the amount of air being supplied to said vortex tube (110).
4. An air assisting system according to claim 1 wherein said first and second valves (118, 120) are proportionate valves.
5. An air assisting system according to claim 1 wherein said regulator (112), said first valve (118) and said second valve 20 are operated by an ECU (106).
6. An air supply system (100) for an internal combustion engine; said air supply system comprising :
- an air assisting system 100 comprising an air reservoir 108 to store air under pressure; a vortex tube (110 connectable to said air reservoir 108 through a regulator to receive pressurized air, said vortex tube (110) having a cold end (114) and a hot end (116); said cold end (114) supplying cold air and said hot end (116) supplying hot air to said engine (102); said cold end (114) connected to a first valve (118) to regulate amount of cold air being supplied to said engine 102; said hot end (116) connected to a second valve (120 to regulate amount of hot air being supplied to said engine (102); a first by-pass path (122) connected to said first valve (118 to release excess cold air to atmosphere; a second by-pass path (124) connected to said second valve (120) to release excess hot air to atmosphere
- an electronic control unit (ECU) (106) to control said regulator (112), said first valve (114 and said second valve (116) in dependence of operating conditions of said engine (102)
- a temperature sensor (104) connected to said ECU (106) to read temperature of air being supplied to said engine (102).
7. A method to operate an air assisting system, said method comprising the steps:
- reading engine parameters
- calculating the temperature of the air to be supplied to an engine (102)
- calculating the required amount of air to be supplied to said engine
(102)
- operating a regulator (112) to allow required amount of air to flow
through a vortex tube (110)
- operating at least one of a first valve (118) and a second valve (120) to

allow air to flow to intake path (126) in dependence of calculated
temperature
, Description:Field of the invention
[0001] This invention relates to the field of air intake systems for internal combustion engines. The invention relates in particular to controlling the temperature of the air entering into the internal combustion engine.

Background of the invention

[0002] Heating the air to supply to an internal combustion for better cold start is known in prior arts. When the temperature is cold, the cold air enters the engine, the atomization of fuel air mixture does not happen optimally and hence the combustion may be affected. In some cases where cold temperatures are observed, the engine may not start immediately.

[0003] For better cold start of an engine, the air is pre-heated before supplying it to the engine. The Indian patent application IN00817MU2009 discloses a device to improve cold startability of vehicles. The device to improve the cold starting of the vehicle comprises of a vortex tube and electronic controller to control the flow through it. The electronic controller receives inputs primarily related to ambient temperature and engine coolant temperature. Based on this it decides the opening duration for the electrical solenoid which supplies the compressed air to the vortex tube. The hot air stream coming out of the vortex tube is supplied to the intake system of the engine during engine cold cranking.

Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0005] FIG. 1 illustrates an air supply system for an internal combustion engine
Detailed description of the embodiments

[0006] Shown in fig. 1 is an air supply system 100 for an internal combustion engine 102. The air supply system shown in fig.1 comprises an air assist system, a temperature sensor 104 and an electronic control unit 106.

[0007] The air assist system comprises an air reservoir 108 to store air under pressure; a vortex tube 110 connectable to said air reservoir 108 through a regulator 112 to receive pressurized air. The vortex tube 110 has a cold end 114 and a hot end 116. The cold end 114 supplies cold air and said hot end 116 supplies hot air to the engine102. The cold end 114 is connected to a first valve 118 to regulate amount of cold air being supplied to engine 102. The hot end 116 is connected to a second valve 120 to regulate amount of hot air being supplied to the engine 102; a first by-pass path 122 is connected to the first valve 118 to release excess cold air to atmosphere. A second by-pass path 124 is connected to the second valve 120 to release excess hot air to atmosphere.

[0008] The invention also discloses method to operate the air supply system, said method comprising the steps: reading engine parameters; calculating the temperature of the air to be supplied to the engine 102; calculating the required amount of air to be supplied to said engine 102; operating the regulator 112 to allow required amount of air to flow through the vortex tube 110; operating at least one of a first valve 118 and a second valve 120 to allow air to flow to intake path 126 in dependence of the calculated temperature.

[0009] The performance of the engine 102 is typically calibrated for a given temperature of air entering the engine 102. This means at that given temperature of the incoming air, the engine is tuned to generate optimum torque. Also the engine performance is influenced by various engine parameters like coolant temperature, engine speed, engine load, ambient temperature, fuel quality etc. These parameters are only for the reference and the list may vary. These parameters shall be factored in when the engine has to generate required torque based on torque demand. Various mathematical models and MAP tables are used to calculate the amount of fuel to be injected into the engine to generate required torque considering the real time engine parameters.

[0010] Whenever there is variation in temperature of incoming air, the engine performance may not be optimum. This is typically compensated by using temperature models of incoming air and providing appropriate correction factors for fuel injection quantity.

[0011] The invention proposes the system using which the engine performance may be brought to optimum performance level at which the engine was calibrated. Assuming that all other engine parameters are appropriately factored in, the invention proposes a system to modify the temperature of the incoming air to the value at which the engine was calibrated. The temperature of incoming air may have to be either increased or reduced depending upon engine parameters. This is done by using a vortex tube 110 and a set of valves 118, 120 to control the amount of hot and/or cold air being supplied to the engine 102.

[0012] The air reservoir 108 stores the pressurized air. The pressurized air is supplied by the engine 102. The air under pressure is supplied to the inlet of the vortex tube 110. The air entering the vortex tube travels inside and the hot air exits through the hot end 116 and the cold air exits through the cold end 114. As the function and construction of the vortex tube is well known, the same is not described in this document. There is a regulator 112 disposed in between the air reservoir 108 and the inlet of the vortex tube 110. The regulator 112 may be an electronic proportional valve. The regulator112 is operated by the ECU 106. Based on the engine parameters, the ECU 106 computes the amount of air to be supplied to the vortex tube 110 and accordingly opens the regulator 112. The pressurized air enters the vortex tube 110 and passes through it, gets separated as hot air and cold air and exits at the hot and cold ends respectively. Based on the requirement of whether the air to be supplied needs to be heated or cooled, the ECU 106 opens the first and second valves appropriately. Based on the requirement, only hot air may be supplied to engine or only cold air may be supplied or a combination of hot and cold air may be supplied to the engine 102.

[0013] If only hot air needs to be supplied to engine then the cold air needs to be released to the atmosphere. Similarly if only cold air needs to be supplied to the engine then the hot air needs to be released to the atmosphere. This is achieved through the first and second valves 118, 120 and the by-pass paths 122, 124. The first and second valves have one inlet and two outlets. The inlet of first valve is connected to cold end 114. The first outlet is connected to pipe leading to intake path 126. The second outlet is connected to first by-pass path 122 to release the cold air into atmosphere. It is similarly arranged with hot end 116 and second valve 120. The valve 124 is operated in such a way that outlet is connected to either the intake path 126 or to the by-pass path 124.

[0014] The temperature of the air to be supplied to the engine 102 is computed by considering the actual ambient temperature and the temperature of the air at which the engine was calibrated. If the ambient temperature is higher than the temperature of the air at which the engine was calibrated, then the air needs to be cooled to bring it down to the calibrated temperature. If the ambient temperature is lower than the temperature of the air at which the engine was calibrated, then the air needs to be heated to bring it up to the calibrated temperature.

[0015] The ECU 106 continuously monitors the engine parameters to compute the amount of air to be supplied to the engine through the regulator 112. The ECU operates the regulator 112 to allow required amount of air to flow to vortex tube 110. The ECU also determines whether the air needs to be cooled or heated and accordingly operates the first and second valves 118, 120.

[0016] For example, when only the cold air needs to be supplied to the engine 102, the first valve 118 is operated in such a way to allow cold air to flow into intake path 126 whereas the second valve120 is operated to block the flow of hot air into intake path 126. Operating the second valve 120 in this case results in hot air flowing into the atmosphere.

[0017] Similarly, when only the hot air needs to be supplied to the engine 102, the second 120 is operated in such a way to allow hot air to flow into intake path 126 whereas the first 118 is operated to block the flow of cold air into intake path 126. Operating the first valve 118 in this case results in cold air flowing into the atmosphere.

[0018] When a combination of hot and cold air needs to be supplied to the engine 102, the valves are operated in such a way that the hot air and cold air flows into the intake path 126.

[0019] The ECU may comprise a microcontroller, memory and programs to operate the air supply system. ECU will have typical input interfaces to read the engine parameters. It will also have output interfaces to operate drive circuits, actuators to control the regulator and the valves. As these input and output interfaces are commonly known, these are not explained in this document.

[0020] The ECU may be implemented as a standalone unit. It is also possible that the existing engine control unit which is already available in vehicles may be used to operate the air supply system.

[0021] The invention provides a system to improve the performance of the engine. Performance may be measured in terms of the torque generated by the engine based on various engine parameters. The invention proposes the air supply system to vary the temperature of the air being supplied to the engine, the temperature of the air being the temperature at which the engine was calibrated. By operating the engine at the calibrated air temperature, the engine will be able to generate optimum torque for the give engine parameters.

[0022] The invention provides a method to operate air supply system 100 using simple steps of reading engine parameters, calculating the required amount of air to be supplied to the engine and calculating the temperature of the air to be supplied to the engine 102. The ECU 106 operators the regulator 112, the first valve 118 and the second valve 120 to supply the required amount of air to the engine 102 at required temperature.