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ASU-600 Series

ASU-600 Series Model No. Breakdown

ASU-600-270-DDP

Above example is a 270 PPM unit powered by Detroit Diesel engine, Trailer mounted unit

Air Start Unit 600 Series Products

100 – 100 PPM 150 – 150 PPM 180 – 180 PPM 270 – 270 PPM 300 – 300 PPM 400 – 400 PPM

DU = Deutz DD = Detroit Diesel CU = Cummins

P = Portable, Trailer Mount S = Skid unit T = Truck Mount at TLD

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ASU-600 Series

I - Description

1. General Unit Description (See Figures 1 & 2) A. The ASU-600 Series Continuous Jet Start Unit is a totally enclosed self-contained truck or trailer

mounted module.

The module features a steel channel base and frame, sheet metal enclosure, hinged doors, instrument panel, hose storage compartment, and removable roof. The panels and doors are formed sheet metal lined with acoustical foam of high absorptive quality. The four doors provide ample access to all components for ease of routine maintenance.

DDP designates a trailer-mounted unit. The unit is equipped with drum type brakes actuated by a lever mounted at the front of the unit near the tow bar.

DDS designates a skid-mounted module. The module is designed to be mounted on any suitable truck chassis.

DDT designates a truck-mounted unit. The module is mounted on a suitable truck at the TLD factory.

The unit is capable of providing a continuous supply of air per its rating and is suitable for starting jet aircraft engines.

The major components are as follows: Heavy duty industrial diesel engine, “dry screw” rotary compressor, delivery air bypass valve, compressor oil heat exchanger, engine radiator, compressor discharge silencer.

The illuminated instrument panel permits selection of “Standby”, “Air Pacs”, "Hangar", or “Jet Start” modes. In addition, a unit display indicates compressor discharge pressure and temperature readings and a warning light for engine and compressor faults is provided.

The unit incorporates a “Demand Type” throttle system. This system controls engine speed so that compressor airflow matches that required by the aircraft to maintain the selected air start pressure. In this manner, minimum airflow is bypassed resulting in high fuel economy.

Options available on the ASU-600 Series Jet Start Unit are listed below.

(1) Ether-Type Cold Weather Starting Aid

(2) Engine Block Heater

(3) Low Fuel Warning

(4) Low Fuel Warning with Ramp Down to Idle or Shutdown

(5) Engine Fuel/Water Separator with/without Heater

(6) Warning Beacons

(7) Sound Attenuation Kit

(8) Third Discharge air outlet

(9) Engine start counter

(10) Tow bar actuated brake kit

(11) Shutoff valve lockout kit

(12) Other options are also available to meet specific customer needs.

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ASU-600 Series

1. ... Doors 2. ... Parking brake 3. ... Running gear 4. ... Tow bar 5…..Hose Bin

JET START UNIT

FIGURE 1

Note: Standard unit shown. Refer to Chapter 4 for actual configuration.

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ASU-600 Series

1. ....Radiator fill 2. ....Engine alternator 3. ....Fuel fill 4 .....Relief valve 5 .....Engine/Compressor coupler access 6 .....Fuel tank

7 .....Engine starter 8 .....Fuel filter/water separator 9 .....Regulator assembly 10 ...Bypass air valve 11 ...Instrument panel 12 ...Shutoff/bleed valve assembly

JET START UNIT FIGURE 2

(SOME PANELS & DOORS REMOVED FOR CLARITY) Note: Standard unit shown. Refer to Chapter 4 for actual configuration.

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2. Major Component Description

For the purposes of orientation and to familiarize operators and maintenance personnel with the location of components, the radiator is considered to be at the front of the unit. The compressor is at the rear. Right and left are determined by standing at the rear end facing the unit.

A. Engine (See Figure 3)

The unit is powered by a 4-cycle Detroit Diesel in-line 6 cylinder turbocharged engine with Detroit Diesel Electronic Control System. The engine is equipped with a 24 VDC automotive type electrical and battery charging system. The engine is equipped with a coolant inhibitor and 2 full flow lube oil filters. As received from the manufacturer, the engine includes the following equipment, which is described in the Detroit Diesel manual (See Chapter 5).

1 ... 24 VDC alternator 2 ... Coolant inhibitor element 3. .. Twin full flow lube oil filters

ENGINE FIGURE 3

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ASU-600 Series

(1) Engine Electronic Control System

The Detroit Diesel Electronic Control System (DDEC) manages critical engine functions to provide optimum fuel economy and emissions control. The system is comprised of an electronic control module (ECM), electronic unit fuel injectors (EUI) and engine sensors. The ECM receives digital/analog electronic input from sensors on the engine and uses the data received to control engine operation. In addition to providing data for efficient fuel combustion, the sensors monitoring engine functions provide data to the ECM for engine protection from failure or damage caused by conditions such as high engine temperature or low oil pressure.

The ECM computes fuel timing and fuel quantity based upon pre-determined calibration maps in its memory. Fuel is delivered to the cylinders by cam driven, solenoid operated electronic fuel injectors. Fuel is mechanically pressurized and electronically metered to ensure precise fuel delivery. The ECM incorporates a diagnostic connector providing industry standard serial communications links with a portable data reader or PC equipped with decoding software for accessing and interpreting display codes.

(2) Electronic Control Module

The engine mounted ECM manages overall engine performance. The ECM continuously performs self-diagnostic checks while monitoring other system components. The ECM data storage and retrieval bank consists of an EEPROM. The EEPROM controls the basic engine functions, such as rated speed and power, fuel injection timing, engine governing, torque shaping, cold start logic, transient fuel delivery, diagnostics, and engine protection. Its control logic achieves fuel efficiency and improved operating economy.

(3) Electronic Unit Injectors

Utilizing the same basic principle as mechanical fuel injectors, the EUI atomizes and meters pressurized fuel flow received from the pump into the combustion chamber of each cylinder. The EUI, however, uses a solenoid operated valve to control injection timing and metering. Fuel injection begins when the solenoid valve is closed. Opening the solenoid valve ends injection. The duration of valve closure determines the quantity of fuel injected.

(4) Engine Sensors

The engine sensors transmit data to the ECM describing engine dynamic performance characteristics. The data is used to monitor and regulate engine performance, to provide diagnostics information, and to activate the engine protection system. This information is also used by the unit control system. Refer to the engine manufacturer’s literature contained in Chapter 5 for further information.

(5) Electronic Governor

The electronic variable speed governor (VSG) holds the engine at a constant speed regardless of load fluctuation as a function of the input signal form the unit control system. The ECM uses the accelerator position, engine speed, and correction variables in conjunction with stored performance mapping to calculate control rod position and volume of fuel injected.

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ASU-600 Series

(6) Engine Protection

The electronic control system records and displays engine fault conditions. The ECM continuously monitors input data received from engine sensors and illuminates the check engine light or stop engine light if a fault condition is detected. When the check engine light illuminates, the condition should be diagnosed as soon as convenient. Automatic engine shutdown is programmed for low coolant level and low oil pressure conditions. Automatic rampdown is programmed for high oil temperature and high coolant temperature conditions. High air filter restriciton will prevent switching from idle to other operating modes. Fault messages on the unit display and electronic engine gauge identify the specific fault condition. Active and inactive fault codes stored in the ECM’s memory can be accessed using the electronic engine gage or by accesing the engine diagnostic connector located on the instrument panel. Inactive codes are logged into memory and time stamped by occurrence. Refer to the Detroit Diesel Operator’s Guide in Chapter 5 for further information.

(a) Oil Pressure Sensor (See Figure 4)

The oil pressure sensor activates the engine protection system if oil pressure drops below programmed signal output level. A low engine oil pressure condition is identified by fault messages on the unit display and electronic engine gauge and the unit status light turning red.

OIL PRESSURE SENSOR FIGURE 4

NOTE: These safety devices are bypassed in Jet Start mode to prevent damage to the aircraft. However, if a fault light illuminates on the unit’s instrument panel, repair the fault as soon as that jet engine start is completed. CONTINUED ATTEMPTS TO RUN THE UNIT WITHOUT REPAIRING IT CAN CAUSE SEVERE DAMAGE TO THE UNIT AND THIS WILL VOID THE WARRANTY.

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ASU-600 Series

(b) Coolant Level Sensor (See Figure 5)

The coolant level sensor sends input data to the ECM that activates the engine protection system if signal output data indicates a low coolant level condition. A low coolant level condition is identified on the instrument panel by warning messages on the unit display and electronic engine gauge and the unit status light turning red.

COOLANT LEVEL SENSOR FIGURE 5

NOTE: These safety devices are bypassed in Jet Start mode to prevent damage to the aircraft. However, if a fault light illuminates on the unit’s instrument panel, repair the fault as soon as that jet engine start is completed. CONTINUED ATTEMPTS TO RUN THE UNIT WITHOUT REPAIRING IT CAN CAUSE SEVERE DAMAGE TO THE UNIT AND THIS WILL VOID THE WARRANTY.

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ASU-600 Series

(6) Air Intake Filter (See Figure 7)

The air filter is a self-contained, disposable assembly with an integral element. The filter consists of a steel housing with a pleated paper filter media providing an air cleaning efficiency of 99.9% (per S.A.E. J726). A rubber elbow and hump reducer secured by a band clamp connect the filter to the engine. A restriction indicator and switch is located on the intake pipe. A high engine air intake condition is indicated by the unit status light turning amber and a warning message on the unit display.

1....Restriction indicator and switch 2....Air filter assembly 3....Mounting clamps

AIR INTAKE FILTER FIGURE 6

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ASU-600 Series

(7) Exhaust System (See Figure 8)

The exhaust system consists of a spark arresting silencer connected to the engine turbocharger through a flexible inlet pipe. Exhaust gases are discharged to the atmosphere through a vertical outlet pipe fitted with a rain cap.

1....Cap, rain 2....Adapter, silencer 3....Bracket, mounting 4....Silencer, exhaust 5....Coupling, Flexible 6....Clamp, V-band

EXHAUST SYSTEM FIGURE 7

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ASU-600 Series

B. Compressor (See Figure 9)

An air-cooled, dry rotary screw compressor, manufactured by Aerzener Maschinenfabrik, Gmbh, Aerzen, Germany, produces the high pressure discharge air required for starting aircraft jet engines. The precisely machined rotors eliminate the need for sealing agents or coatings that may erode or fail due to variable expansion of the rotors inside the housing. Timing gears and air cooling to reduce thermal expansion prevent contact between the rotors, housing, and end plates to maintain high compressor efficiency throughout its life span. An integral gearbox increases input shaft rpm delivered by the engine to the highest efficient rotor operating speed in order to achieve maximum compressor performance.

Lubricating oil is circulated through a fan cooled compressor oil heat exchanger mounted on the side of the air compressor. The compressor oil heat exchanger fan is compressor driven.

The compressor is protected from damage resulting from low oil pressure or high oil temperature during operation by a safety circuit that causes the engine to shutdown should these conditions occur. This safety circuit is overridden when the unit is placed in jet start mode in order to protect the aircraft engines. There is also a safety circuit which prevents switching to operating modes other than idle if there is a high compressor air filter intake restriction.

1....Air inlet filter assembly 2....Restriction indicator and switch 3....Air discharge port 4....Cooling fan 5....Compressor oil heat exchanger 6....Oil breather

COMPRESSOR FIGURE 8

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(1) Compressor Protective Devices (a) Oil Pressure Switch (See Figure 10)

The low oil pressure switch will shut the unit down in the event that the compressor oil pressure falls below 15 psi. A low compressor oil pressure condition is identified by a fault message on the unit display and the unit status light turning red.

1....Port access 2....Switch, oil pressure 3....Filter, oil

OIL PRESSURE SWITCH FIGURE 9

NOTE: These safety devices are bypassed in Jet Start mode to prevent damage to the aircraft.

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ASU-600 Series

(b) Oil Temperature Switch (See Figure 11)

The compressor high oil temperature switch will shut the unit down in the event that the compressor lubricating oil temperature rises above 215oF (101.7oC). A high compressor oil temperature condition is identified by a fault message on the unit display and the unit status light turning red.

OIL TEMPERATURE SWITCH FIGURE 10

NOTE: These safety devices are bypassed in Jet Start mode to prevent damage to the aircraft.

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ASU-600 Series

(c) Discharge Temperature Sensor (See Figure 12)

The compressor high discharge temperature sensor will shut the unit down in the event that the compressor discharge temperature rises above 480°F. A high compressor discharge temperature condition is identified by a fault message on the unit display and the unit status light turning red.

The minimum engine speed will increase to improve compressor cooling in the event that the compressor discharge temperature rises above 450°F.

DISCHARGE TEMPERATURE SENSOR FIGURE 11

DUAL DISCHARGE OUTLET CONFIGURATION SHOWN; REFER TO CHAPTER 4 FOR OTHER CONFIGURATIONS

NOTE: The high temperature shutoff is bypassed in jet start mode to

prevent damage to the aircraft.

1 .....Discharge Temperature Sensor

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ASU-600 Series

(d) Black Box Recorder

The Black Box Recorder is installed on Air start units to continuosly monitor the compressor discharge pressure and operating mode and store data into internal flash memory for future analysis.

The Black Box Pressure Recorder is a part of the jet start proteection circuit of the air start units. If the black box pressure recorder is disconnected by way of removing the power source or the pressure source, it will not allow the unit to operate in Jet Start, Hangar, or Air Pac modes.

CONTROL BOX

FIGURE 12 STANDARD CONFIGURATION SHOWN; REFER TO CHAPTER 4 FOR OTHER CONFIGURATIONS

1..... Black Box Recorder

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ASU-600 Series

C. Delivered Air System (See Figure 13)

Whenever the engine is running, air is drawn into the compressor through the air filter assembly installed on the compressor inlet. The air filter cleans the supply air and dampens inlet noise.

The air compressor is equipped with mating helically grooved rotors that operate in constant mesh to provide seamless compression of intake air. The rotor set is comprised of a lobed male rotor and a fluted female rotor that capture the air stream drawn into the compressor through the suction inlet and compresses its volume in the interlobe space between the male and female rotors. As the rotors mesh, the air is compressed between the rotors and is drawn toward the discharge outlet where it is released into the delivery line.

The dense, high pressure volume of air released by the compressor enters the discharge silencer; the silencer dampens noise from the compressor discharge. Compressed air leaves the silencer and enters the air delivery manifold where it is either partially or entirely bypassed to the atmosphere by the bypass valve or delivered to the aircraft through the shut-off/bleed valve.

The compressor outlet port supplies a pressure signal through a sensing line to the inlet of the electronic pressure regulator valve. Signal air is filtered through an in-line filter/water separator. The regulator valve provides adjustable (0-30 psig) signal pressure to the bypass valve actuating piston. The vent solenoid valve relieves air from the bypass valve actuating piston when de-energized. The regulator controls the position of the bypass valve, which regulates delivered air pressure and flow to the aircraft. (1) Air Pacs Mode

With the unit running at idle, selecting “air pacs” energizes the air delivery control solenoid (L5) through the normally closed air delivery pressure switch (S9). Also energized is the signal pressure regulator (V34) which pressurizes the pneumatic cylinder of the bypass valve. With shutoff valve(s) (V36) and (V42) closed, air will be diverted through the bypass valve (V1). Opening the shutoff valves (V36) or (V42) will deliver air to the aircraft at the pressure established by the regulator valve (V34). Delivered air pressure above 43 psi opens the air delivery pressure safety switch (S9) and de-energizes the air delivery control solenoid (L5). Delivered air flow is bypassed until air pressure drops below 32 psi. The signal pressure regulator provides an adjustable signal pressure of 0-30 psig to the air delivery control solenoid valve. In the energized position the air delivery control solenoid valve provides this signal air pressure to the bypass valve actuating piston; when de-energized the air delivery control solenoid removes the pressure from the actuating piston, allowing the delivered air to bypass.

In either the “air pacs,” 'hangar," or “standby” mode, a compressor or engine fault will result in unit shutdown, the unit status light turning red, and a fault message on the unit display. The palm button emergency stop switch (S23) may be used for emergency unit shut down.

(2) Hangar Mode

With the unit running at idle, selecting “Hangar” energizes the air delivery control solenoid (L5) through the normally closed air delivery pressure switch (S9). Also energized is the signal pressure regulator (V34) which pressurizes the pneumatic cylinder of the bypass valve.

NOTE: Air Pacs pressure may be adjusted per customer preference.

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ASU-600 Series

With shutoff valve(s) (V36) and (V42) closed, air will be diverted through the bypass valve (V1). Opening the shutoff valves (V36) or (V42) will deliver air to the aircraft at the pressure established by the regulator valve (V34). Delivered air pressure above 43 psi opens the air delivery pressure safety switch (S9) and de-energizes the air delivery control solenoid (L5). Delivered air flow is bypassed until air pressure drops below 40 psi. The signal pressure regualtor provides an adjustable signal pressure of 0-30 psig to the air delivery control solenoid valve. In the energized position the air delivery control solenoid valve provides this signal air pressure to the bypass valve actuating piston; when de-energized the air delivery control solenoid removes the pressure from the actuating piston, allowing the delivered air to bypass.

In either the “air pacs,” 'hangar," or “standby” mode, a compressor or engine fault will result in unit shutdown, the unit status light turning red, and a fault message on the unt display. The palm button emergency stop switch (S23) may be used for emergency unit shut down.

(3) Jet Start Mode

With the unit running at idle, selecting “jet start” energizes the air delivery control solenoid (L5) through the normally closed air delivery pressure switch (S9). Also energized is the signal pressure regulator (V34) which pressurizes the pneumatic cylinder of the bypass valve. With shutoff valve(s) (V36) and (V42) closed, air will be diverted through the bypass valve (V1). Opening the shutoff valves (V36) or (V42) will deliver air to the aircraft at the pressure established by the regulator valve (V34). Delivered air pressure above 43 psi opens air delivery pressure safety switch (S9) and de-energizes air delivery control solenoid (L5). Delivered air flow is bypassed until air pressure drops below 40 psi. The air pacs regulator provides an adjustable signal pressure of 0-30 psig to the air delivery control solenoid valve. In the energized position the air delivery control solenoid valve provides this signal air pressure to the bypass valve actuating piston; when de-energized the air delivery control solenoid removes the pressure from the actuating piston, alowing the delivered air to bypass.

The unit shut down system is disabled in the “jet start” mode to avoid hazard to the aircraft engine(s). An engine or compressor fault condition will not shut down the unit. The emergency stop switch (S23) is not disabled in "jet start." When a fault condition occurs in the “jet start” mode, the unit will continue running while the unit status light turne red and a fault message is shown on the unit display to alert the equipment operator of the fault condition.

WARNING: Hangar mode should not be used for starting aircraft engines.

The unit safeties are not disabled in hangar mode; an engine or compressor fault will shut the unit down, possibly resulting in

catastrophic failure of the aircraft engine.

NOTE: Hangar mode may be deleted from some units or may have

different pressure settings depending on customer preference.

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ASU-600 Series

1. ....Discharge silencer 2. ....Relief valve 3. ....Air delivery pipe 4. ....Air bypass valve 5. ....Regulator assembly 6. ....Shut off/bleed valve assembly

DELIVERED AIR SYSTEM

FIGURE 13

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WARNING:

DO NOT LEAVE UNIT RUNNING IN JET START MODE UNATTENDED AS ALL THE PROTECTIONS ARE DISABLED.

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ASU-600 Series

D. Control System

(1) System Overview The control system for the unit is based on a Programmeable Logic Controller (PLC) that is housed in the control box. The PLC interfaces with the ECM, the unit sensors, and the user interface. The PLC provides instructions to the engine over the J1939 data link with the ECM. The delivered air system is controlled by a set of outputs to the regulator and valves.

(2) Delivered Air Pressure Control The pressure of the air that is delivered to the aircraft is regulated by the bypass valve assembly (V1). The bypass valve cylinder is pressurized in jet start, hangar, and air pacs modes. This pressure holds the trim valve shut until the delivered air pressure is sufficient to open it, and then provides variable back pressure in the delivered air manifold to hold the delivered air pressure at the target pressure.

The air delivery control solenoid valve (L5) is a normally open valve that closes when energized. When the L5 valve is open, the bypass valve cylinder is not pressurized. When it is closed, the cylinder can pressurize. The L5 valve is powered by the PLC (via the air delivery pressure switch) when the unit is in jet start, hangar, or air pacs modes.

The signal pressure regulator (V34) provides signal air at variable pressure to the bypass valve cylinder. The pressure of this air determines the pressure of the air in the delivered air manifold. The signal pressure regulator output is controlled by a 1-9 V DC signal; output pressure is linearly proportional to the voltage signal. The PLC outputs a PWM signal that is converted into a voltage signals by the PWM -> 0-10 VDC converter (E10.) This signal then controls the signal pressure regulator. The output of the PLC is based on current operating mode and barometric pressure.

a. Calibration

The PWM output of the PLC is based on the current operating mode and a lookup table in the software that provides PWM output for a given delivered air pressure setpoint. This table is populated by the PLC program's calibration functions.

In the 'Calibrate Pr-Reg' Menu of the unit display can be found 'Quick Auto-Cal' and 'Full Auto-Cal.' The full auto-cal will calibrate the PWM output for all possible delivered air pressures, including those for altitudes other than the current altitude. The quick auto-cal will calibrate the PWM output for only those delivered air pressures and altitudes which have been used by the unit in question before.

Calibration will only be necessary if a control component has been replaced. If calibration is needed, the unit should be placed in 'idle' with the discharge valves closed. Once the desired calibrate function has been selected, the unit will run through the calibration cycle with the unit display indicating the progress of the calibration cycle. Once the calibration cycle has been complete, the unit should go through a performance check, and will then be ready for normal operations.

There is an 'auto-cal' function which runs in the background of the PLC program continuously. This function continuously compensates for any drift that may have occurred as the unit and components wear or ambient conditions change.

(3) Throttle Control (See Figure 16)

Because the compressor is a positive displacement or “constant mass flow” source, a portion or all of the air flow will at times need to be bypassed to the atmosphere. This depends on what the flow capacity required by a particular aircraft is and whether the internal aircraft ports are open to accept air flow.

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ASU-600 Series

The engine speed determines how much air is created, while the current operating mode and setting of the signal pressure regulator will control how much air is bypassed and how much is delivered to the aircraft. Engine speed is controlled by the unit PLC based on input from the trim height sensor (R18) and the delivered air pressure sensor (S16).

Depending on the selected mode; “jet start,” "hangar," or “air pacs,” the signal pressure regulator (V34) will provide a signal pressure to the bypass valve (V1) actuator piston. This signal pressurizes the bypass valve cylinder, providing the force to hold the trim valve closed if delivered air pressure is low, while letting the trim valve open and air to bypass if the pressure begins to rise.

The trim height sensor (R18) monitors the height of the trim in the bypass valve (V1.) The trim valve opens as the trim moves up to allow more air to bypass and closes as the trim moves down, restricting the bypass air. As the trim valve opens and the sensed height increases, an error signal is generated in the PLC that too much air being created, and is bypassing. The PLC then causes the engine to decelerate until the trim drops or the minimum engine speed is reached. If the trim valve closes completely, an error signal is generated in the PLC that too little air is being created. The PLC then causes the engine to accelerate until the trim has lifted and the bypass valve is very slightly open, which is the nominal operating condition.

As the backpressure against the bypass valve is fixed for a given operating mode, variations in delivered air pressure are caused by variations in the compressor flow from the aircraft demand. The delivered air pressure sensor (S16) monitors the pressure of the air being delivered to the aircraft. As the pressure deviates from the setpoint for the given operating mode, an error signal is generated by the PLC. If the pressure is too high, the PLC signals the engine to decelerate; if the pressure it too low, the PLC signals the engine to accelerate.

When the unit shut-off/bleed valves are closed or the aircraft valves are closed, the pressure in the unit delivered air piping will increase and the bypass valve will open. Based on the signals from the trim height sensor and the delivered air pressure sensor, the PLC will signal the engine to decelerate until the minimum engine speed is reached. When the valves are opened and the aircraft begins taking air the bypass valve will close and the delivered air pressure will drop. Based on the signals from the trim height sensor and the delivered air pressure sensor, the PLC will signal the engine to accelerate until the required flow is reached; i.e. the pressure is at its setpoint and the bypass valve is slightly open. If the demand from the aircraft is sufficient to require the full output of the unit, the bypass valve will not open and the acceleration will stop when the engine speed reaches its maximum.

The error signals from the trim height and delivered air pressure both pass through gain functions before being combined into the Proportional-Integral-Derivative function that the PLC uses to determine how rapidly to accelerate or decelerate. This allows the unit to react rapidly to significant variations in trim height and pressure, but more slowly to minor variations, thereby preventing overshoot and engine hunting.

a. Sensor Drift Compensation

When the unit is powered on, the PLC logs the output of the trim height sensor and the delivered air pressure sensor. If these are outputs are not zero, the control system then zeroes the outputs by making the initial sensor reading the offset. In this way minor variations in the sensors are compensate for.

If the sensors drift, the offset will increase. If the offset drifts past a certain threshold, a warning message will appear on the unit display, alerting the user to the need to replace or calibrate the offending sensor.

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ASU-600 Series

1... Trim Height Sensor 2... Delivered Air Pressure Sensor

THROTTLE CONTROL FIGURE 14

(4) Miscellaneous Functions a. Unit Display

The unit display normally indicates the unit status, operating mode, fuel level, delivered air pressure, and delivered air temperature. Depending on the options included with the unit, other information may be available by scrolling up and down the display.

b. Warnings and Faults

The control system incorporates the unit safeties that protect the engine and compressor from damage. These safeties include:

1. Engine high coolant temperature

2. Engine high oil temperature

3. Engine low oil pressure

4. Low Coolant Level

5. Compressor Low Oil Pressure

6. Compressor High Oil Temperature

7. Compressor High Discharge Air Temperature

8. Low fuel level (option)

These safeties will shut down or roll back the unit if they occur unless the unit is in 'jet start' mode; in 'jet start' mode, all safeties display a warning message and trigger the unit status light to go to red.

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There are warnings that do not cause the unit to ramp down or shut down, but will cause the unit display to show a warning message and may prevent the unit from switching out of 'standby' mode. These include:

1. Engine air filter inlet clogged

2. Compressor air filter inlet clogged

3. Black Box Recorder fault

c. Warmup and Cooldown

If the engine oil is cold when the engine is started the unit will go into 'warmup' mode. In this mode, the mode selector switch is disabled. The unit will accelerate to a fast-idle speed in order to build heat more quickly. The unit display will indicate that the unit is in 'warmup' mode, showing the engine oil temperature that must be reached to come out of 'warmup' mode and the current engine oil temperature. The unit status light will switch amber during the warmup. Once the engine oil temperature reaches the target temperature the unit will come out of warmup and go to whatever mode is currently selected.

When the engine stop button is depressed the unit enters the cooldown cycle. To prevent damage to the compressor the unit has to idle for 3 minutes before shutting down. If the unit has not been in 'standby' mode for at least three minutes when the engine stop button is pressed, the a countdown to automatic engine stop will begin and be shown on the unit display. Once the countdown has expired, the engine will stop automatically. During the cooldown cycle the engine start/stop pushbutton will flash and the unit status light will switch to amber. The mode selector switch will not function during the cooldown, but it may be stopped at any time by pressing the engine start/stop button again.

d. Automatic Power Down

If the unit power is left on for 30 minutes after the engine is stopped it will automatically be turned off. This can be temporarily disabled for maintenance purposes in the unit display menu by navigating to 'Settings,' 'Maintenance.'

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ASU-600 Series

(5) Menu Navigation The unit display normally displays the information necessary for unit operation along with any information that pertains to the options of the unit. The unit display also contains a menu system that can be used to look up more detailed data, test certain safeties, and change some settings. This menu system can be accessed by pressing the 'scroll up,' 'scroll down,' 'select.' and 'escape' pushbuttons simultaneously.

Maintenance Menu

Unit Information

AIR PRESS-ACT

AIR PRESS-SP

AIR PRESS-OFFSET

AIR PRESS-MAX-SP

BAROMETIC PRESS

PRESS REG PWM-SP

TRIM HEIGHT

TRIM HEIGHT OFFSET

Records

E-Stop Count

Fault History

Warning History

Eng-Start Count

Eng-Hourmeter

JS Overrun Count

Software

PLC Software

Display Software

Calibration

Quick Auto-Cal

Full Auto-Cal

Testing

High Air Temp

Low Fuel Level

JS Overrun Counter

Eng Start Counter

Beacon

Settings

Unit Model

Options

Maintenance

Auto Power Off

Sensors

Low Fuel

E-Stop Counter

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ASU-600 Series

E. Aircraft Protection Devices (See Figure 17)

The delivered air pressure switch (S9) protects the aircraft and unit compressor from pressures in excess of 43 psig. When actuated, it de-energizes the air delivery control solenoid valve (L5), which will exhaust pressure from the bypass valve actuating cylinder. Air will then be vented to the atmosphere.

In addition to the pressure switch, the aircraft and compressor are protected from over pressure by a relief valve located in the air delivery manifold. This valve is set at 46 psig and is capable of venting the entire supply of delivered air.

The shut-off/bleed valves provide delivered air through the hoses and aircraft coupler when the valves are in the open position. Flow is shut off to the aircraft when the valve handle is in the closed position. This position also allows for venting the supply hose through the bleed valve so that the hoses may be de-pressurized before disconnecting them from the aircraft.

1. .. Relief Valve 2. .. Pressure Switch 3. .. Air Delivery Control Solenoid Valve (L5) 4. .. Shutoff/bleed Valve Assembly

AIRCRAFT PROTECTION DEVICES FIGURE 15

DUAL DISCHARGE OUTLET CONFIGURATION SHOWN; REFER TO CHAPTER 4 FOR OTHER CONFIGURATIONS

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ASU-600 Series

F. Control Box (See Figure 19)

The control box houses the programmable logic controller that controls the unit operations, the engine diagnostic connector, and unit fuses. The door of the control box contains the instrument panel.

The programmable logic controller (PLC) controls the unit, interfacing with the ECM, the unit sensors, and the instrument panel. It regulates operating speed and pressure, and monitors the unit safeties.

1... Programmable Logic Controller 2... Engine Diagnostic Connector 3... Unit Fuses

CONTROL BOX

FIGURE 16

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G. Instrument Panel (See Figure 20)

The instrument panel provides mounting facilities for the engine and compressor controls. The following instruments and controls are mounted on the instrument panel assembly.

INSTRUMENT PANEL ASSEMBLY FIGURE 17

NOTE: STANDARD PANEL SHOWN. REFER TO CHAPTER 4 FOR ACTUAL CONFIGURATION.

1.....Panel light 7 ......Engine Start/Stop Pushbutton 2.....Electronic Engine gage 8 ......Emergency Stop 3.....Unit Display 9 ...... 'Select' Pushbutton 4.....Unit Status Light 10 .... 'Escape' Pushbutton 5.....Selector Switch 11 ....Scroll Up Pushbutton 6.....Power On/Off Pushbutton 12 ....Scroll Down Pushbutton

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(1) Panel Light

Illuminates the instrument panel to aid in nighttime operation. Continuously on when unit power is on.

(2) Electronic Engine Gage

The electronic engine gage displays engine operating parameters and engine fault messages on an LCD display for easy reading. Some major parameters that the Electronic Engine gage displays are:

(a) Engine RPM

(b) Engine Load

(c) Engine Coolant Temperature

(d) Engine Manifold Temperature

(e) Engine Oil Pressure

(f) Engine Operating Voltage

(g) Engine Hours Run

(h) Engine Fuel Economy

(i) Engine Fault Codes

(3) Unit Display

The unit display indicates unit operating parameters and status messages on an LCD display. Some major parameters that the Unit Display shows are:

(a) Fuel Level

(b) Delivered Air Pressure

(c) Delivered Air Temperature

(d) Unit Operating Mode

(e) Unit Status

The unit display may display additional information based on version and options.

The unit display acts as the user interface for accessing some options and settings and displaying unit history.

(4) Unit Status Light

Multi-colored LED indicator light. Illuminates green for 'ready,' amber for 'warning,' and red for 'fault.'

(5) Selector Switch

A four position rotary switch that enables the operator to select either “Standby”, “Air Pacs”, "Hangar", or “Jet Start” mode.

(6) Power On/Off Pushbutton

Hold to turn unit power on; press again to turn unit power off.

(7) Engine Start/Stop Pushbutton

Hold to start engine; press again to start shutdown cycle.

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ASU-600 Series

(8) Emergency Stop Switch

Immediately shuts down unit.

(9) 'Select' Pushbutton

For navigating Unit Display menus.

(10) 'Escape' Pushbutton

For navigating Unit Display menus.

(11) Scroll Up Pushbutton

For navigating Unit Display menus.

(12) Scroll Down Pushbutton

For navigating Unit Display menus.

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ASU-600 Series

1. Optional Equipment Description

(1) Detroit Diesel "DDEC" Automatic Ether Start Kit, 24 VDC

Detroit Diesel Electronic Controls (DDEC) Ether Start System is an automatic cold weather starting system using the engine’s electronic controls and sensors to assist the diesel engine in cold weather starting conditions. The amount of ether is controlled to optimize the starting process and prevent engine damage.

(2) Engine Block Heater, 120 VAC or 240 VAC

Heats the engine coolant to prevent damage to engine components due to freezing and provides easier starting in cold weather.

(3) Warning Beacon

24 VDC lamp mounted on top of unit flashes to attract attention. Activated when engine is running. May be flashing, rotating, or steady.

(4) Fuel Filter/Water Separator with Heater, 24 VDC

Separates water and contaminants from fuel by centrifugal action. Heater turns on as the fuel temperature drops below 30oF (-1.1oC) to eliminate waxing or icing at the filter element for easier starting and running of the engine in cold weather.

(5) Hush Kit

Reduces noise output of the unit.

(6) Low Fuel Warning System

A program that indicates a warning on the unit status light, displays an error message on the unit display, and activates a beacon on the roof when a low fuel condition is detected. Activated when approx. 15% of fuel remains.

(7) Low Fuel Warning and Ramp-down to Idle System

A program that indicates a warning on the unit status light, displays an error message on the unit display, and activates a beacon on the roof when a low fuel condition is detected. Activated when approx. 15% of fuel remains. If fuel continues to reduce (about a 5% of a tank remaining), engine will ramp down to idle. Ramp-down is disabled in jet start mode.

(8) Low Fuel Warning and Shutdown System

A program that indicates a warning on the unit status light, displays an error message on the unit display, and activates a beacon on the roof when a low fuel condition is detected. Activated when approx. 15% of fuel remains. If fuel continues to reduce (about a 5% of a tank remaining), engine will ramp down to idle, then begin 3 minute cooldown cycle and shut down. Ramp-down to idle and shut down are disabled in jet start mode.

(9) Clearance Lights

4 marker lights installed on the top corners of the unit for indication that the unit is running

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ASU-600 Series

(10) Engine Start Counter

Program to have the unit log and display engine start count in the records section of the unit display.

(11) Emergency Stop Counter

Program to have the unit log and display emergency stop count in the records section of the unit display.

(12) Jet Start Overrun Counter

Program to have the unit log and display in the records section of the unit display instances when the unit is left in Jet Start Mode for more than 7 minutes.

(13) Jet-A Fuel Compatibility

Program that changes the unit ready temperature to meet engine requirements for Jet-A operation.

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