Abstract:
An oscillating air motor includes one or more cylinders that house a piston. The piston is connected to a crankshaft by a connecting rod. The cylinders are in fluid communication with a solenoid valve that supplies air to the cylinders. The air is forced into the cylinders at a predetermined time causing the piston to move down the cylinders. The cylinder are supported by at least a countershaft that passes through the cylinders. The cylinders are permitted to move about the countershaft. Movement of the cylinders about the countershaft may be used to control input and output valves of the motor. Alternatively, sensors activated by a cam on the camshaft may be used control input and output solenoid valves. Using a two way transfer valve, the engine may be switched to pump mode for regenerative braking.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to air motors. More particularly, the present invention relates to an air motor that uses an electronic switching system to control one or more valves of the motor.  
       SUMMARY OF THE INVENTION  
       [0002]     The invention includes an air motor that includes an electronic switching system to control valves of the air motor. The electronic switching system may control both the input valve for optimizing air expansion during a power stroke of the air motor, and a transfer valve that is used to convert the air motor to a pump for recovering braking energy of a vehicle using the air motor when a braking action is applied. Air captured during braking is pumped into air tanks. Air in these tanks is then fed back into the air motor, now acting as a motor, to accelerate the vehicle back to speed after braking.  
         [0003]     According to one embodiment of the invention, an oscillating air motor includes one or more cylinders that house a piston. The piston is connected to a crankshaft by a connecting rod. The cylinders are in fluid communication with a solenoid valve that supplies air to the cylinders. The air is forced into the cylinders at a predetermined time causing the piston to move down the cylinders. The cylinder are supported by at least a countershaft that passes through the cylinders. The cylinders are permitted to move about the countershaft. Movement of the cylinders about the countershaft is used to control input and output valves of the motor. Additionally, the piston runs parallel to the cylinder such that forces transferred from the piston into the cylinder are reduced and the use of low friction material such as, for example, TEFLON® in the piston and cylinder walls allows for oil-less operation of the motor whether implemented as an air motor or as a steam engine.  
         [0004]     According to one embodiment of the invention, an oscillating air motor includes one or more cylinders that house a piston. The piston is connected to a crankshaft by a connecting rod. The cylinders are in fluid communication with solenoid valves that supply air to the cylinders and open exhaust valves during an exhaust phase of motor operation. Air is forced into the cylinders when a pulse is sent to the solenoid valves controlling the air admitted to the cylinders. The air causes the piston to move down the cylinders. The cylinders are supported by a countershaft that passes through brackets mounted on the top of the cylinders. The cylinders are permitted to move about the countershaft. This movement allows the pistons to run parallel to the cylinder such that forces transferred from the piston into the cylinder are reduced to a point where low friction piston rings and cylinder liners allow for oil-less operation of the motor whether implemented as an air motor or as a steam engine.  
         [0005]     The invention may also include conical piston seals that seal the piston inside the cylinder in such a way that the more the pressure presses down on the cylinder, the more the piston pushes against the cylinder wall, thus sealing the piston/cylinder gap. This type of conical piston seal provides for a more efficient air motor or a closed cycle steam engine.  
         [0006]     The invention may also include conical washers that may be used within an exhaust valve of an air motor and the exhaust and input valve of a steam engine. Conical washer shape increases an effectiveness of an air seal provided in the motor which increases an efficiency of motors using the washers. The conical washers may also be used in a three-way transfer valve that switches operation of the motor from among a primary power source, a braking energy recuperation pump, and a recouped air acceleration function.  
         [0007]     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto.  
         [0008]     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.  
         [0009]     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a side perspective view of an air motor according to one embodiment of the invention.  
         [0011]      FIG. 2  is a cross-sectional side view of an air motor according to one embodiment of the invention.  
         [0012]      FIG. 3  illustrates a cutaway view of an exhaust valve of an air motor in three operational states according to one embodiment of the invention.  
         [0013]      FIG. 4  is a schematic block diagram of an air motor according to one embodiment of the invention.  
         [0014]      FIG. 5  illustrates a contactor mechanism of an air motor in four operational states according to one embodiment of the invention.  
         [0015]      FIG. 6  illustrates a conical piston and a conical washer of an air motor according to one embodiment of the invention.  
         [0016]      FIG. 7  is a schematic block diagram of an air motor according to one embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     According to one embodiment, the invention includes a device that includes an air powered, two cylinder air motor. The device includes two cylinders  1 ,  2  supported by a countershaft  3  and a crankshaft  4  as illustrated in  FIG. 1 . Preferably, the cylinders  1 ,  2  are lined with a friction-reducing material such as, for example, TEFLON®, although other materials may be used.  
         [0018]     The countershaft  3  and crankshaft  4  are supported by countershaft bearings  5 ,  6 ,  7  and crankshaft bearings  8 ,  9 ,  10 ,  11 ,  12 , respectively. Both the countershaft  3  and crankshaft  4  are also supported by side support  13 ,  14  and center support  15 . The side supports  13 ,  14  and center support  15  may be held in place by top plate  16  and bottom plate  17 .  
         [0019]     Connecting rods  18 ,  19  provide a linkage between the crankshaft  4  and the cylinders  1 ,  2 . The connecting rods  18 ,  19  are secured to the crankshaft  4  at one end by pins  20 ,  21 . The pins  20 ,  21  pass through connecting rod bearings  22 ,  23  that are provided in each of the connecting rods  18 ,  19 . During operation of the motor, the crankshaft  4  rotates causing the connecting rods  18 ,  19  to move in an elliptical manner about the crankshaft  4 . The cylinders  1 ,  2  pivot around the countershaft  3  as the connecting rods  18 ,  19  move downward and outward as the crankshaft  4  rotates. Energy needed to rotate the crankshaft  4  may be stored in, for example, a flywheel  24  mounted on the crankshaft  4 . Additional supports  25 ,  26  may also be provided to support the crankshaft  4 .  
         [0020]     As shown in  FIG. 2 , the crankshaft  4  includes a plurality of crankshaft links  27 ,  28 ,  29 ,  30  that connect the crankshaft  4  to the connecting rods  18 ,  19 . Cylinders  1 ,  2  are supported by countershaft  3  which is supported by countershaft bearings  5 ,  6 ,  7  which are mounted in side supports  13 ,  14  and center support  15 . According to one embodiment of the invention, additional center supports  31 ,  32  may be secured to the center support  15 . The countershaft bearings  6  may also be provided in the additional center supports  31 ,  32 . Therefore, the crankshaft  3  may pass through the side supports  13 ,  14 , cylinders  1 ,  2 , center support  15 , additional center supports  31 ,  32 , and countershaft bearings  5 ,  6 ,  7 .  
         [0021]     Cylinders  1 ,  2  are sealed at the top by cylinder heads  33 ,  34  that preferably are press fitted against the countershaft  3  and attached to cylinders  1 ,  2 . Conical pistons  35 ,  36  and piston backings  37 ,  38  are attached to one end of the connecting rods  18 ,  19 . The pistons  35 ,  36  and piston backings  37 ,  38  move the connecting rods  18 ,  19  up and down inside the cylinders  1 ,  2 .  
         [0022]     The connecting rods  18 ,  19  are supported by connecting rod guides  39 ,  40  that are attached to the bottom of the cylinder heads  33 ,  34 . According to one embodiment of the invention, the connecting rod guides  39 ,  40  are provided with a friction-reducing material such as, for example, TEFLON®, although other materials may be used. The connecting rod guides  39 ,  40  may be, for example, coated with TEFLON® or other friction-reducing material. Connecting rods  18 ,  19  transfer their motion to the crankshaft segments  41 ,  42 ,  43  by pins  20 ,  21  which are supported by bearings  22 ,  23  and crankshaft links  27 ,  28 ,  29 ,  30 .  
         [0023]      FIG. 3  illustrates an exhaust valve  44  of an air motor in three operational states according to one embodiment of the invention. The exhaust valve  44  includes a valve body  45  with a side pipe  46  for connecting the exhaust valve  44  to a cylinder head. A plunger  47  is provided within the valve body  45  that slides therein. The plunger  47  includes an upper conical washer  48 , a spacer  49 , a lower conical washer  50 , linkage rods  51 ,  52  that connect the exhaust valve  44  with a motion of cylinder  1  as it moves back and fourth about a countershaft  3 .  
         [0024]     Three operational states of the exhaust valve  44  are shown in  FIG. 3 . Operational state ( 1 ) is neutral. This is when a piston is at top dead center and the exhaust valve  44  is closed. In operational state ( 2 ), the piston is traveling upwardly causing the cylinder to sway downwardly thus pulling the plunger downwardly and allowing air from the cylinder to pass through to the outside. In operational state ( 3 ), the cylinder is moving in an opposite direction as described in state ( 2 ) during a power stroke of a cylinder and the exhaust valve  44  remains closed.  
         [0025]      FIG. 4  shows the electrical and pneumatic connections of an air motor according to one embodiment of the invention. Air enters a throttle valve  53  and is then directed to a splitter  54 . The splitter  54  divides the air from the throttle valve  53  and directs the air to one of two solenoids  55 ,  56 , one for each cylinder  1 ,  2 . Air leaves the solenoid valves  55 ,  56  and flows into the cylinders  1 ,  2 . The solenoids  55 ,  56  preferably run on 12 volts to be compatible with automotive accessories.  
         [0026]      FIG. 5  illustrates a contactor assembly  57  of an air motor in four operational states according to one embodiment of the invention. Electrical connections are made from solenoids (not shown) to a commutator  58  formed by contactor posts  59 ,  60  mounted to the top of the cylinders  1 ,  2  and contact flaps  61  mounted to the top of a motor  62  using a mounting plate  63 . The contactor assembly  57  moves back and forth around a countershaft ( 64 ). Proper activation of input valve solenoids is achieved using the contactor assemblies provided on the top of each cylinder.  
         [0027]     The contactor posts  59 ,  60  make contact with two conductive strips  65 ,  66  mounted on the contact flap  61  that is fastened to the mounting plate  63  that is attached to the top of the motor  62 . One of the conductive strips  65  is shorter than the other conductive strip  66 . When the shorter conductive strip  65  is selected, it makes a shorter contact with the contactor post  58  than the longer conductive strip  66  which makes a longer contact with the contactor post  60 . The contactor posts  59 ,  60  control the duration of an input valve opening.  
         [0028]     According to one embodiment of the invention, the shorter conductive strip  65  makes a short contact with the contactor post  59  allowing a small charge of air to enter the cylinder  1  that is allowed to expand while pushing a piston (not shown) down the cylinder  1 . This extracts an increased amount of energy from air that has been compressed. The longer conductive strip  66  makes a longer contact with contactor post  60  allowing more air at full pressure into the cylinder  1  resulting in more power.  
         [0029]     The four operational states of the contactor assembly  57  are illustrated in  FIG. 5 . During operational state ( 1 ), the piston is at top dead center and no contact is made. This is the neutral state. In operational state ( 2 ), as the flywheel causes the crankshaft to rotate, the top of the cylinder moves and urges the contactor posts  59 ,  60  toward the contactor flap  61  having the conductive strips  65 ,  66  thus making contact and opening the solenoid valve for that cylinder. In operational state ( 3 ), as the top of the cylinder continues to turn, the shorter conductive strip  65  loses contact with contactor post  59 , however, contact continues between contactor post  60  and the longer conductive strip  66 . In operational state ( 4 ), the piston has moved past bottom dead center. The contactor posts  59 ,  60  have moved past the contact flap  61  and is moving back to its vertical position. As the contactor posts  59 ,  60  have passed under the contact flap  61 , they no longer make contact with the conductive strips  65 ,  66  and thus the input solenoid for this cylinder remains closed while another cylinder is in a power stroke. The cylinders are 180 degrees out of phase, therefore, this process alternates between the two cylinders providing a smooth power stroke with two power impulses per revolution of the crankshaft.  
         [0030]      FIG. 6  illustrates a conical piston  67  and a conical washer  68  that may be used with an air motor according to one embodiment of the invention. The conical piston  67  has a flared skirt  69  that points toward a cylinder head (not shown). Some of the air pressure created by the air motor is diverted toward the cylinder (not shown) by virtue of the conical piston geometry. This assists in sealing space between the cylinder and the piston without using piston rings and increasing an effectiveness of an air seal while the air motor is operating.  
         [0031]     In an exhaust valve, skirts  70  of the conical washers  68  point toward each other and use pressure in the cylinder to force the skirts  70  against an exhaust valve body. This provides a seal between the plunger and the exhaust valve body that reduces an amount of air passing therebetween. Preferably, the seal is air tight.  
         [0032]      FIG. 7  is a schematic block diagram of an air motor according to one embodiment of the invention. The air motor includes input valve module  71 , input solenoid valve  72 , output solenoid valve  73 , and an output valve module  74 . The input valve modules  71 ,  74  are in communication with corresponding solenoid valves  72 ,  73 . The solenoid valves are in communication with a two way transfer valve  75 . The two-way transfer valve  75  is in communication with a brake cylinder  76 , check valve  77 , and cylinder  78 .  
         [0033]     The two way transfer valve  75  which switches the air motor between an engine mode and a pump mode. When operated as a pump, the solenoid valves  72 ,  73  do not provide input to the air motor because, as a pump, only check valve  77  is needed between the air motor and an energy recuperation tank. This also reduces a likelihood that high pressure in the energy recuperation tank will reach the solenoid valves  72 ,  73 .  
         [0034]     In pump mode, the input and output valve modules  71 ,  74  preferably are disabled. During motor operation, a crankshaft sensor  79  senses when a crankshaft has just moved past top dead center. This may be performed by sensing a location of a cam on a camshaft or crankshaft. When this occurs, the sensor  79  transmits a pulse to the input valve module  71  providing an indication that the crankshaft has just moved past top dead center. The input valve module  71  transmits a signal to the input solenoid valve  72  causing the input solenoid valve  72  to open.  
         [0035]     The length of the pulse may vary according to needs of a driver operating a vehicle using the air motor. According to one embodiment, the input solenoid valve  72  is closed early (less than 15 degrees after top dead center). To prevent pulse overrun, the sensor  80  may also include a cut-off sensor that signals the input valve module  71  to close if the pulse causes the input solenoid valve  72  to remain open for more than 160 degrees past dead center. The output valve module  74  preferably keeps the output solenoid valve  73  open from 180 degrees to 360 degrees past top dead center.  
         [0036]     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. For example, although the invention has been described in terms of a two-cylinder motor, any suitable number of cylinders may be used. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.