Air compressor for a vehicle air braking system

1 . A vehicle air compressor comprising:

a crankcase having a longitudinal central axis; and

a head assembly including

a rear face that lies in a plane transverse to the longitudinal central axis of the crankcase,

a cylinder head, the cylinder head including an air inlet port oriented in the same plane as the rear face, an air outlet port oriented in the same plane as the rear face, and a coolant outlet port oriented in the same plane as the rear face, and

a valve plate located between the cylinder head and the crankcase, the valve plate including a coolant inlet port oriented in the same plane as the rear face.

2 . A vehicle air compressor according to claim 1 , wherein the head assembly includes

at least one inlet reed valve having a tongue axis that is transverse to the longitudinal central axis of the crankcase.

3 . A vehicle air compressor according to claim 2 further comprising:

an unloader valve having a piston axis that is transverse to the longitudinal central axis of the crankcase and is offset relative to the longitudinal central axis such that the piston axis and the longitudinal central axis of the crankcase are non-intersecting.

4 . A vehicle air compressor according to claim 1 , wherein a portion of the head assembly defines at least in part a serpentine-shaped coolant passage interconnecting the coolant inlet port and the coolant outlet port and through which coolant can flow to cool components of the compressor during operation of the compressor.

5 . A vehicle air compressor according to claim 4 , wherein the serpentine-shaped coolant passage is substantially W-shaped.

6 . A vehicle air compressor according to claim 1 , wherein the cylinder head has a substantially U-shaped passage through which compressed air can flow to the air outlet port to be discharged away from the compressor.

7 . A vehicle air compressor according to claim 1 , wherein the head assembly includes a baffle plate positioned between the cylinder head and the valve plate.

8 . A vehicle air compressor comprising:

a crankcase having a longitudinal central axis;

a head assembly having

a rear face that lies in a plane transverse to the longitudinal central axis of the crankcase,

a cylinder head, the cylinder head including an air inlet port oriented in the same plane as the rear face, an air outlet port oriented in the same plane as the rear face, and a coolant outlet port oriented in the same plane as the rear face, and

a valve plate located between the cylinder head and the crankcase, the valve plate including a coolant inlet port oriented in the same plane as the rear face; and

at least one inlet reed valve positioned between the crankcase and the cylinder head and having a tongue axis that is transverse to the longitudinal central axis of the crankcase.

9 . A vehicle air compressor according to claim 8 further comprising:

an unloader valve positioned within the cylinder head and having a longitudinal central axis that lies in a plane transverse to the longitudinal central axis of the crankcase and is offset relative to the longitudinal central axis of the crankcase such that the longitudinal central axes are non-intersecting.

10 . A vehicle air compressor according to claim 8 wherein the head assembly further

defines a serpentine-shaped coolant passage through which coolant can flow to cool components of the compressor during operation of the compressor.

11 . A vehicle air compressor according to claim 10 , wherein the serpentine-shaped coolant passage is substantially W-shaped.

12 . A vehicle air compressor according to claim 10 further comprising:

a baffle plate positioned between the cylinder head and the valve plate.

13 . A vehicle air compressor according to claim 8 , wherein the cylinder head has a substantially U-shaped passage through which compressed air can flow to be discharged away from the compressor.

14 . An air compressor comprising:

a compressor head assembly defining a cylinder head having an air inlet port, an air outlet port, and a coolant outlet port, and a valve plate having a coolant inlet port, wherein the four ports are oriented in a common plane as a single face of the compressor head assembly;

wherein the valve plate has a first serpentine-shaped internal coolant passage and the cylinder head has a second serpentine-shaped internal coolant passage that cooperates with the first serpentine-shaped internal coolant passage to provide enhanced cooling of the compressor head assembly during operation of the compressor.

15 . A method of operating an air compressor having a rear face that lies in a plane, the method comprising:

receiving intake air through an air intake port of a cylinder head, the air intake port oriented in the same plane as the rear face of the air compressor;

delivering compressed air through an air discharge port of the cylinder head, the air discharge port oriented in the same plane as the rear face of the air compressor;

receiving cooled coolant through a coolant inlet port of a valve plate, the coolant inlet port oriented in the same plane as the rear face of the air compressor; and

delivering high-temperature coolant through a coolant outlet port of the cylinder head, the coolant outlet port oriented in the same plane as the rear face of the air compressor.

16 . A method according to claim 15 further comprising:

passing the cooled coolant through a substantially double-winding W-shaped internal coolant passage created by the cooperation of the cylinder head and the valve plate to allow the cooled coolant to cool components of the air compressor during operation of the air compressor.

17 . A method according to claim 15 further comprising:

passing compressed air through a substantially U-shaped internal air passage during operation of the air compressor.