The crankshaft is turned by the rear wheels through the differential, the drive shaft, the transmission, and the clutch. This is during a downhill operation. The speed of the vehicle can be reduced when a braking force is applied to the crankshaft. The braking force is attained when the BrakeSaver converts the energy of rotation into heat. The heat is removed by the engine cooling system.
BrakeSaver Components
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| Illustration 1 | g00292547 |
BrakeSaver Components (1) Flywheel housing. (2) Rotor. (3) BrakeSaver housing. (4) Flywheel. (5) Crankshaft flange. (6) Ring gear plate. (7) Stator. | |
The BrakeSaver housing (3) is fastened directly to the rear face of the flywheel housing (1). The BrakeSaver adds approximately four inches to the length of the engine drive train. A rotor (2) and a ring gear plate (6) are installed between the rear flange of the crankshaft (5) and the flywheel (4). The engine can use a standard starter motor with the ring gear plate (6). The rotor turns in a space between the stator (7) and BrakeSaver housing (3).
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| Illustration 2 | g00292548 |
BrakeSaver Components (8) The rear section of the oil pump. (9) BrakeSaver. (10) Tube. (11) Hole. (12) Bypass valve. (13) Baffle. (14) The front section of the oil pump. (15) Engine Oil pan. (16) BrakeSaver control valve. (17) Line. (18) Line. | |
The engine oil pump has two sections. The front section (14) of the oil pump gives oil to the engine for lubrication. The rear section (8) of the oil pump sends engine oil through the BrakeSaver control valve (16) to the BrakeSaver (9). The rear section of the oil pump also sends oil through line (17) to the engine oil cooler (not shown). From the oil cooler, the cool oil goes through line (18), through baffle (13) and back into the engine oil pan (15) .
The tube (10) allows the oil in the BrakeSaver to rapidly go out of the BrakeSaver when the BrakeSaver is turned off. This oil returns to the engine oil pan.
The oil has a high viscosity when the engine is cold (starting conditions). The high viscosity causes a restriction to the oil flow through the oil cooler. A restriction in the oil cooler will result in an oil pressure difference in the bypass valve (12). The oil pressure difference will cause the valve to open. An open bypass valve will cause the oil from the rear section of the oil pump to go through hole (11) in the bypass valve (12). The oil drains back into the engine oil pan (15) .
BrakeSaver Lubrication
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| Illustration 3 | g00292550 |
BrakeSaver Lubrication (1) Oil line. (2) Orifice. (3) Piston type ring seal. (4) Orifice. (5) Chamber. (6) Piston type ring seal. (7) Lip type seal. (8) Lip type seal. (9) Oil drain line. | |
The lip type seals (3) and (6) keep pressure oil in the chamber (5) around the rotor during operation. Lip type seals (7) and (8) prevent oil leakage from the BrakeSaver. The outside oil line (1) from the engine lubrication system sends engine oil to the BrakeSaver housing. The orifices (2) and (4) in the BrakeSaver send oil to the space between the lip seals and the piston type ring seals at a rate of 1.24 L/min (0.33 US gpm). The oil lubricates the seals under all conditions of operation.
The spaces between the lip type seals and the piston type seals are connected to an outside oil drain line (9). The line allows the oil to return to the engine oil pan.
BrakeSaver Operation
The crankshaft is turned by the rear wheels through the differential, the drive shaft, the transmission, and the clutch. This is during a downhill operation. The speed of the vehicle is reduced by applying a braking force to the crankshaft. The braking force is attained when the BrakeSaver converts the energy of rotation into heat. The heat is removed by the engine cooling system.
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| Illustration 4 | g00292551 |
BrakeSaver Housing And Rotor (1) BrakeSaver housing. (2) Pocket. (3) Hole. (4) Pocket. (5) Rotor. | |
The rotor (5) is fastened to the engine crankshaft. The rotor turns with the engine crankshaft. The rotor has pockets (4) on the outer circumference of both sides. The rotor has four holes (3). The pockets and the holes permit an equal flow of oil to both sides of the rotor.
The BrakeSaver housing (1) and the stator are fastened to the flywheel housing. The BrakeSaver housing and the stator can not turn. Pockets (2) are located on the inside surfaces of the BrakeSaver housing and the stator. These pockets are in alignment with the pockets (4) in the rotor.
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| Illustration 5 | g00292592 |
Oil Flow Through BrakeSaver (1) BrakeSaver housing. (2) Pocket. (4) Pocket. (5) Rotor. (6) Stator. | |
A compartment is created by the stator (6) and the BrakeSaver housing (1). The rotor (5) turns in the compartment. When the BrakeSaver housing is in operation, engine oil comes into this compartment. Oil comes into the compartment through a passage. This passage is located near the center of the bottom of the BrakeSaver housing. Oil is thrown outward as the rotor turns with the crankshaft. As the oil flows outward, the shape of the rotor pockets (4) send the oil into pockets (2) of the stator and BrakeSaver housing. The oil takes the shape of a spiral as the rotor turns and the oil flows around the BrakeSaver compartment.
The oil is constantly cut by the vanes (material between the pockets) of the rotor as the oil flows around the BrakeSaver compartment. This cutting action gives resistance to the rotor and changes the energy of the rotor into heat in the oil. The heat is removed by the oil cooler within the engine cooling system.
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| Illustration 6 | g00292593 |
Oil Flow In BrakeSaver (1) BrakeSaver housing. (5) Rotor. (6) Stator. (7) Spiral flow. (8) Air pocket. | |
More oil starts to flow in a spiral shape between the rotor and the stator when the BrakeSaver inlet passage opens. An air pocket (8) is inside this spiral flow (7) of oil. As the pressure in the rotor compartment increases, the amount of oil in the spiral flow increases in thickness and the air pocket has compression. The amount of oil that is cut by the rotor vanes increases as the compression in the air pocket increases.
The level of braking can be controlled by the inlet oil pressure when the BrakeSaver is in operation. The braking force is in direct relation to the amount of oil that is cut by the rotor vanes. The inlet passage to the rotor compartment is closed by the control valve. There is no oil in the BrakeSaver compartment when the BrakeSaver is not in operation.
BrakeSaver Control
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| Illustration 7 | g00292595 |
BrakeSaver Oil Flow Is (Off) (1) BrakeSaver control lever. (2) Oil cooler. (3) Valve spool. (4) BrakeSaver control valve. (5) Oil pump. (6) BrakeSaver. (7) Line. (8) Oil pan. | |
When the BrakeSaver control lever (1) is in the OFF position, spring force holds valve spool (3) against the cover at the air inlet end of the BrakeSaver control valve (4). With valve spool (3) in this position, oil pump (5) sends engine oil from oil pan (8) through the BrakeSaver control valve (4) to the oil cooler (2). From the oil cooler, the oil goes through the control valve, through line (7) and back to the engine oil pan (8). With the BrakeSaver control valve in this position, no oil is sent to the BrakeSaver (6).
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| Illustration 8 | g00292596 |
BrakeSaver Oil Flow (Fill) (1) BrakeSaver control lever. (2) Oil cooler. (3) Valve spool. (4) BrakeSaver control valve. (5) Oil pump. (6) BrakeSaver. (7) Line. (8) Oil pan. | |
When the BrakeSaver control lever (1) is moved to the ON position, pressure air moves valve spool (3) to the right against the spring force. With the valve spool in this position, engine oil from the oil pump (5) is sent through the BrakeSaver control valve (4) to the rotor compartment of the BrakeSaver (6). From the BrakeSaver, the oil goes through the control valve, through oil cooler (2), back through the control valve, and back into the BrakeSaver.
The oil cannot go back to the engine oil pan (8) because the passage through the control valve to line (7) is closed by the valve spool.
The time that is required to fill the BrakeSaver with pressure oil to the point of maximum braking in the BrakeSaver is approximately 1.8 seconds.
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| Illustration 9 | g00292597 |
BrakeSaver Oil Flow (Operate) (1) BrakeSaver control lever. (2) Oil cooler. (3) Valve spool. (6) BrakeSaver. (8) Oil pan. | |
As BrakeSaver (6) fills, the turning rotor causes an increase in the oil pressure in the BrakeSaver. The inlet oil and the outlet oil of the BrakeSaver goes into the spring bore of the valve spool (3). Force works against the pressure air on the left end of the valve spool. This force is the average of the inlet oil pressure and the outlet oil pressure in the spring bore plus the force of the spring. When the force of the pressure oil plus the spring force become larger than the force of the pressure air the valve spool moves to the left. This movement causes a restriction in the passage for the inlet oil. This restriction causes a decrease in oil pressure in the BrakeSaver.
A decrease in rotor speed will cause a decrease in the oil pressure in the BrakeSaver. This causes a decrease in oil pressure in the spring bore of the valve spool. The spool will move to the right because air pressure is exerted on the left end of the spool. This movement opens the passage for the inlet oil and the oil pressure in the BrakeSaver increases.
An increase in rotor speed will cause an increase in the oil pressure in the BrakeSaver. This increase in the oil pressure will cause the valve spool to move to the left. Inlet oil is then restricted to the BrakeSaver.
The valve spool is constantly moving. This movement makes adjustments to the BrakeSaver inlet pressure to compensation for the changing rotor speeds caused by normal operation of the vehicle. This constant movement of the valve spool is necessary to keep the amount of braking force in the BrakeSaver at the level set by the BrakeSaver control lever (1) .
During normal operation, the outlet oil from the BrakeSaver goes to oil cooler (2). From the oil cooler, some of the oil (approximately 60 percent) goes back to the BrakeSaver inlet and the remainder of the oil from the oil cooler goes to engine oil pan (8).
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| Illustration 10 | g00292598 |
BrakeSaver Oil Flow (Drain) (1) BrakeSaver control lever. (2) Oil cooler. (3) Valve spool. (4) BrakeSaver control valve. (5) Oil pump. (6) BrakeSaver. (7) Line. (8) Oil pan. (9) Line. | |
When the BrakeSaver control lever (1) is moved to the OFF position, the pressure air on the left end of the valve spool (3) goes out of the control valve (4). With no pressure air in the valve, the pressure oil in the spring bore plus the spring force move the valve spool against the cover at the air inlet end of the control valve. This movement closes the BrakeSaver inlet passage. The rotor in the BrakeSaver (6) pushes the oil out of the BrakeSaver. From the BrakeSaver, the oil goes through the control valve, through line (9) and back to the engine oil pan (8) .
The time that is required to remove the oil from the BrakeSaver is approximately 1.5 seconds.
With the control valve in this position, oil pump (5) sends oil through oil cooler (2) and through line (7) back to the oil pan.
Operator Controls
Two types of controls are available for the BrakeSaver: a manual control and an automatic control.
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| Illustration 11 | g00292599 |
Manual Control Diagram (1) Pressure reducing valve. (2) Manual control valve. (3) BrakeSaver control lever. (4) Air Pressure gauge. (5) Oil temperature gauge. (6) BrakeSaver control valve. | |
Manual Control
Pressure air from the truck air system is sent to pressure reducing valve (1). The air pressure is controlled to 345 kPa (50 psi). This controlled pressure air goes to manual control valve (2) .
When the operator moves the BrakeSaver control lever (3) toward the ON position, pressure air is sent to the BrakeSaver control valve (6). A higher pressure of air is sent to the BrakeSaver control valve when the lever (3) is moved further toward the ON position. An increase in air pressure in the BrakeSaver control valve causes an increase in the oil pressure in the BrakeSaver. An increase in the oil pressure in the BrakeSaver causes an increase in the braking force in the BrakeSaver. The operator can give modulation to the braking force in the BrakeSaver through the movement of BrakeSaver control lever (3) .
When the BrakeSaver is turned off, the pressure air goes out of the system through a passage in manual control valve (2). Pressure air is released out of the BrakeSaver control valve (6). This removes the braking force from the BrakeSaver.
An air pressure gauge (4) gives the operator a relative indication of the air pressure that is being sent to the BrakeSaver control valve. The operator can approximately get the same braking effect from the BrakeSaver. This is accomplished by using the indication of the air pressure gauge in relation to the engine rpm. This allows the operator to more easily control the desired wheel speed of the vehicle.
An oil temperature gauge (5) gives the operator an indication of the ability of the engine cooling system to control the heat in the BrakeSaver during operation. If the gauge registers HOT, the operator should move the BrakeSaver control lever (3) to the OFF position. The operator should use the service brakes to control the wheel speed of the vehicle. The oil temperature will become normal again when the BrakeSaver is off. The operator can use the BrakeSaver once the temperature returns to the normal temperature.
| NOTICE |
|---|
Do not manually engage the BrakeSaver and control the wheel speed with the accelerator. The design of the cooling system is for the control of the temperature of the oil at full engine power or full BrakeSaver capacity, but not both at the same time. |
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| Illustration 12 | g00292600 |
Automatic Control Diagram (1) Manual control valve. (2) Pressure reducing valve. (3) BrakeSaver solenoid relay. (4) BrakeSaver ON/OFF switch. (5) Circuit protection. (6) Battery. (7) Air pressure gauge. (8) Double check valve. (9) Electronic Control Module (ECM). (10) Oil temperature gauge. (11) BrakeSaver control valve. (12) BrakeSaver solenoid valve. | |
Automatic Control
All the components of the manual control are in the automatic control. All the components function in the same manner. In the automatic control, there is also a BrakeSaver solenoid valve (12), a double check valve (8), and the ECM. When the BrakeSaver solenoid valve (12) is activated, the BrakeSaver solenoid valve (12) sends pressure air from the pressure reducing valve (2) to the BrakeSaver control valve (11). The BrakeSaver solenoid valve (12) is connected to the ECM (9) .
The mode selector switch has two positions: MANUAL and AUTOMATIC.
When the electric current opens the BrakeSaver solenoid valve (12), full air pressure 345 kPa (50 psi) is sent through the double check valve (8) to the BrakeSaver control valve (11). The double check valve keeps the pressure air from going out of the system through the manual control valve (1) when the control lever of the manual control valve (1) is not active. The double check valve also keeps the pressure air from going out of the system through the BrakeSaver solenoid valve (12) when the manual control is active.
Because the solenoid valve sends full air pressure to the BrakeSaver control valve (11), there is no modulation in the AUTOMATIC position.
When the BrakeSaver is turned off, the pressure air goes out of the system through a passage in the manual control valve (1) or in the BrakeSaver solenoid valve (12). The pressure air is out of the BrakeSaver control valve (11) and the braking force is removed from the BrakeSaver.
The manual control valve (1) can be operated with the mode selector switch in the AUTOMATIC position. During normal operation, the solenoid valve will send full air pressure to the BrakeSaver control valve. This will remove the effect of the manual control valve. The manual control valve will have an effect when the mode selector switch is in the AUTOMATIC position and there is an electrical system failure.
Manual control valve (1) can also be operated with the engine system in the Cruise Control Mode. Under this condition, the cruise control switch is in the ON position. When the Cruise Control Mode is in operation, the air pressure is directed to the BrakeSaver control valve (11) and to the BrakeSaver ON/OFF switch (4). The cruise control circuit is disabled when the BrakeSaver ON/OFF switch (4) opens.