Electronic engine - air compressor system

An electronically controlled diesel engine for a vehicle which may act as an air compressor in addition to acting as a power source for the vehicle. When acting in the air compressor function, one end cylinder is converted to the function to provide compressed air to air tanks on the vehicle. The air from this combination compressor and power cylinder may be used to fill air tanks which provide air for braking in vehicles such as heavy trucks. The combination compressor and power cylinder has an exhaust isolation valve in the exhaust manifold to isolate an air collection area and a relief/check valve engaged on an upstream side to the air collection area and to an air tank in the air system for the vehicle on the downstream side. An electronic controller means controls the fuel injector for the combination compressor and power cylinder and the exhaust isolation valve. Various types of diesel engines may be modified to become an electronic engine-air compressor system in accordance with this invention.

BACKGROUND OF THE INVENTION 
The present invention relates to an electronically controlled diesel engine 
for a vehicle which may act as an air compressor in addition to acting as 
a power source for the vehicle. When acting in the air compressor 
function, one end cylinder is converted to the function to provide 
compressed air to air tanks on the vehicle. The air from this combination 
compressor and power cylinder may be used to fill air tanks which provide 
air for braking in vehicles such as heavy trucks. Various types of diesel 
engines may be modified to become an electronic engine-air compressor 
system in accordance with this invention. 
Prior Art 
Heretofore, diesel engines have existed which may be temporarily act as air 
compressors. One type of prior art diesel engine which could act as an air 
compressor involved tapping off pressurized air output from the turbo 
charger from the intake manifold. This prior art diesel engine is shown in 
U.S. Pat. No. 4,429,532. Diesel engines have a sets of combustion 
cylinders which have pistons which cycle in the cylinders when the engines 
are operated. Should fuel be shut off to the fuel injectors of one of 
these combustion cylinders during engine operation while maintaining the 
piston movement, efficient compression of air entering the cylinder will 
occur and exhausting to the exhaust manifold. The prior art diesel engine 
shown in U.S. Pat. No. 4,429,532 did not take advantage of this air 
compression in the cylinder to pressurize air for the vehicle air system. 
Diesel engine cylinders have an intake valve and an exhaust valve. The 
intake valves, exhaust valves and injection valves cycle open and closed 
to allow the pistons to reciprocally move in the cylinders through an 
intake stroke, a compression stroke, an expansion stroke, and an exhaust 
stroke. Another prior art diesel engine electronically varied the movement 
of two or half of the pistons in the cylinders of an in-line four cylinder 
diesel engine to reverse motor the impacted cylinders. The fuel injectors 
in the reverse motoring cylinders would be shut off and the compressed gas 
would be discharged via the intake valves to the intake manifold. An 
example of this type prior art engine is shown in U.S. Pat. No. 5,226,401. 
Although this engine did involve air compression in an engine cylinder 
starved of fuel, there was a complex scheme involved in varying the 
movement of the intake and exhaust valves from their normal cycling for 
combustion. Additionally, the engine shown in U.S. Pat. No. 5,226,401 was 
not engaged to the vehicle's air system to allow controlled delivery of 
pressurized air. Air compressed in this prior art engine was redirected to 
the intake manifold to assist in engine pollutant reduction. 
Another type prior art engine with a compressor function is shown in U.S. 
Pat. No. 3,744,934 where some of the cylinders may be converted to a 
compressor function. An engine internal switching means was required to 
accomplish the dual function so as to vary intake and exhaust valve 
cycling. 
None of the prior art mentioned diesel engines with air compressor 
functions could be easily manufactured from simple modifications to an 
existing diesel engine exhaust system without varying intake and exhaust 
valve cycling. 
Heretofore, an electronically controlled diesel engine for a vehicle which 
may act as an air compressor has not been suggested which utilizes the 
exhaust stroke of one piston of a cylinder of the engine, is capable of 
discharging the exhausted air to the vehicle air system, does not vary the 
cycling of the engine intake and exhaust valves and which may be easily 
manufactured with simple modifications to an existing diesel engine. 
SUMMARY OF THE INVENTION 
Accordingly, it is a primary object of the invention to provide an 
electronically controlled diesel engine for a vehicle which may act as an 
air compressor which utilizes the exhaust stroke of one piston of a 
cylinder of the engine to compress air in an isolated portion of the 
exhaust manifold. 
A second object of the invention is to provide a diesel engine which may 
act as an air compressor which is capable of discharging the exhausted air 
to the vehicle air system to recharge an air tank in the air system. 
A third object of the invention is to provide a diesel engine which may act 
as an air compressor that does not vary the cycling of the engine intake 
and exhaust valves to achieve the air compression. 
A fourth object of the invention is to provide a diesel engine which may 
act as an air compressor which may be easily manufactured with simple 
modifications to the exhaust manifold of an existing diesel engine. 
All the objects of the invention are satisfied with an electronically 
controlled diesel engine for a vehicle which when acting in the air 
compressor function, one end cylinder is converted to the function to 
provide compressed air to air tanks on the vehicle. More specifically, 
there is an exhaust isolation valve in the engine's common exhaust 
manifold which closes to isolate the portion of the exhaust manifold where 
the compressor cylinder discharges exhaust gases. This isolable portion of 
the exhaust manifold has a tap off to a relief/check valve. The discharge 
from this relief/check valve is directed to an air tank in the vehicle's 
air system. When the combination compressor and power cylinder is shifted 
to the compressor function, the exhaust isolation valve closes and the 
fuel injector for the cylinder secures injecting fuel due to signals from 
an electronic controller for the engine. Air pressure builds up in the 
isolated section of the exhaust manifold as the cylinder continues to 
cycle with the engine continuing to run. When the air pressure achieves a 
preset value, the relief/check valve opens to transfer the compressed air 
to the air tank. When the air tanks achieve a present pressure, the 
exhaust isolation valve opens to release the exhaust gases to the normal 
discharge path and the relief/check valve closes as pressure in the 
previously isolated portion of the manifold decreases.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings in greater detail, in FIGS. 1 to 5, there is 
shown an electronically controlled diesel engine 10 for a vehicle 101 (not 
shown) which may act as an air compressor in addition to acting as a power 
source for the vehicle 101 made in accordance with this invention. The 
engine 10 includes an engine block 11 with cylinder bores 12 to define 
cylinders 13. Within each cylinder 13 is a piston 14 to reciprocally move 
in the cylinders 13 through an intake stroke, a compression stroke, an 
expansion stroke, and an exhaust stroke when the engine 10 operates. Each 
said piston 14 is mechanically engaged to a crank shaft 51 (not shown). 
Each cylinder 13 additionally has an intake valve 21, an exhaust valve 22, 
and a fuel injector 23. The intake valve 21 and the exhaust valve 22 open 
and close in concert with pressurized injection of fuel by the fuel 
injector 23 to cause the four separate strokes of the piston 14. The 
engine 10 includes an intake manifold 15, engaged to the engine block 11, 
which defines an intake manifold passage 16 and a plurality of 
interconnected intake manifold branch passages 17. The intake manifold 
branch passages 17 are in fluid communication with the intake valves 21. 
The engine 10 further includes a turbocharger 18 having an incoming turbo 
air compressor 24 and an exhaust gas driven turbine 25. The compressor 18 
is operatively connected to the intake manifold 16 by an intake conduit 26 
providing supercharged air to combustion chambers 27 of the cylinders 13. 
A cooler 47 is interposed in the intake conduit 26 between the compressor 
18 and the intake manifold passage 16. An exhaust manifold 28 is engaged 
to the engine block 11 for conducting gas from the exhaust valves 22 and 
hence the combustion chambers 27. The exhaust manifold 28 defines an 
exhaust manifold passage 29 and a plurality of interconnected exhaust 
manifold branch passages 30. The exhaust manifold branch passages 30 are 
in fluid communication with the exhaust valves 22. The exhaust gas turbine 
25 is operatively connected to the exhaust manifold passage 29 by an 
exhaust gas conduit 32. Exhaust gas from the combustion chambers 27 drives 
the turbine 25 which in turn drives the turbo air compressor 24 in a 
conventional manner. 
One end cylinder 13 is designated as a combination compressor and power 
cylinder 19 to provide compressed air upon demand to an air tank 102 in 
the air system 103 (not shown) on the vehicle 101. The combination 
compressor and power cylinder 19 may operate in either a power generation 
mode as shown in FIGS. 2 and 4, or; the combination compressor and power 
cylinder 19 may also operate in an air compression mode as shown in FIGS. 
3 and 5. More specifically, there is an exhaust isolation valve 33 in the 
exhaust manifold branch passage 30 engaged to the exhaust valve 22 for the 
combination compressor and power cylinder 19. When the exhaust isolation 
valve 33 closes, an air collection area 34 of the exhaust manifold branch 
passage 30 associated with the combination compressor and power cylinder 
19 is isolated. The exhaust isolation valve 33 is shown as a flapper 
valve, however, it may be any valve which will isolate the air collection 
area to accumulate air pressure increases and will also provide little 
head loss when the exhaust isolation valve 33 is open. The air collection 
area 34 is operatively engaged to a relief or one way check valve 35 
through an air supply line 36 on an upstream side of the relief/check 
valve 35. The relief/check valve 35 is set to open a preset value of air 
pressure on the upstream or the air collection area 34 side of the 
relief/check valve 35. In the preferred embodiment, the relief/check valve 
35 will open when the pressure in the air collection area 34 reaches or 
exceeds forty pounds per square inch gauge (40 psig). The discharge from 
the relief/check valve 35 is directed on the downstream side to the air 
tank 102 through air piping 41. There is an air dryer 42 operatively 
engaged in the flow path in air piping 41 between the relief/check valve 
35 and the air tank 102 in the air system 103. 
The engine 10 has an electronic controller means 93 (not shown) of type 
commonly used on modern day diesel engines. The electronic controller 
means 93 which may be programmable controls the operation of the exhaust 
isolation valve 33 and the fuel injector 23 of the combination compressor 
and power cylinder 19. This control results in the combination compressor 
and power cylinder 19 shifting between the power generation and air 
compression modes. The air system 103 contains pressure sensors 111 (not 
shown) which detect pressure in the air tank 102. The pressure sensors 111 
provide input signals to the electronic controller means 93 so the 
electronic controller means will shift to between the combination 
compressor and power cylinder 19 between the power generation and air 
compression modes. During the power generation mode, the electronic 
controller means 93 allows normal injection of fuel through the fuel 
injector 23 of the combination compressor and power cylinder 19 to the 
combustion chamber 27 and maintains the exhaust isolation valve 33 in an 
open position to allow passage of exhaust gases to the exhaust gas conduit 
32. When air pressure in the air tank 102, reaches a preset value, the 
electronic controller means 93 shifts the combination compressor and power 
cylinder 19 to the air compression mode as follows. Fuel injection through 
the fuel injector 23 of the combination compressor and power cylinder 19 
is stopped. The piston 14 of the combination compressor and power cylinder 
19 continues to cycle as does the intake valve 21 and the exhaust valve 
22. This cycling of the piston 14 causes the air collection area 34 to be 
purged of combustion gases. The preferred number of piston 14 cycles is 
when five (5) times the volume of the air collection area 34 has flowed 
through the air collection area 34. This should prevent contamination of 
the air system 103 of gaseous combustion products. After the air 
collection area 34 is purged, the electronic controller means 93 closes 
the exhaust isolation valve 33 to isolate the air collection area 34. As a 
result air pressure builds up in the air collection area 34 as the piston 
14 continues to cycle in the combination compressor and power cylinder 19. 
When air pressure in the air collection area 34 reaches a preset value, 
preferably 40 psig, the relief/check valve will open discharging 
pressurized air to the air tank 102 through the air dryer 42. Once air 
pressure in the air tank 102 increases to a preset value, preferably 120 
psig, the electronic controller means 93 will open the exhaust isolation 
valve 33. This will cause a pressure reduction in the air collection area 
34 and as a result cause the relief/check to close. The electronic 
controller means 93 will then allow operation of the fuel injector 23 for 
the combination compressor and power cylinder 19 to return the cylinder to 
the power generation mode. 
The electronic controller means 93 will shift the combination compressor 
and power cylinder 19 to the air compression mode whenever the pressure in 
the air tank 102 or in the air system 103 is less than a high setpoint of 
preferably approximately 120 psig and the driver is not depressing an 
accelerator pedal 108 (not shown) of the vehicle 101. The cylinder 19 will 
return to the power generation mode when air pressure reaches 120 psig. 
This higher setpoint will ensure air recharging of the air tank 102 occurs 
only when there is no power demand on the engine 10. The electronic 
controller means 93 will shift the combination compressor and power 
cylinder 19 to the air compression mode whenever the pressure in the air 
tank 102 or in the air system 103 falls below a low setpoint of preferably 
approximately 100 psig regardless of the whether the accelerator pedal 108 
is depressed and stay in the air compression mode until air pressure 
reaches 100 psig. This lower setpoint ensures that that there will be air 
for braking in the air tank 102 regardless of power needs. There may also 
be a dash board mounted indicating lamp 109 (not shown) indicating when 
the combination compressor and power cylinder 19 is in the air compression 
mode. 
Various types of diesel engines may be converted to an engine 10 in 
accordance with this invention by merely replacing the factory supplied 
exhaust manifold branch passage 30 with one with an exhaust isolation 
valve 33 and a relief/check valve engaged to an air tank 102, by adding a 
pressure sensor 111 to the air system 103 which provides signals to the 
electronic controller means 93, and by reprogramming the electronic 
controller means 93 in accordance with the above described control scheme. 
As described above, the engine 10 with the combination compressor and power 
cylinder 19 of the present invention provides a number of advantages, some 
of which have been described above and others of which are inherent in the 
invention. Also modifications may be proposed to the engine 10 with the 
combination compressor and power cylinder 19 without departing from the 
teachings herein. Accordingly, the scope of the invention is only to be 
limited as necessitated by the accompanying claims.