C280 Marine Engines System Overview Caterpillar


System Overview
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1.1. Controllers
2.2. Primary and Secondary Electronic Control Module (ECM)
3.2. Redundant Engine Control Feature
4.2. Control Assembly
5.2. Exhaust Temperature Module
6.1. Local Engine Control Panel (LEC Panel)
7.2. "READY TO START" Lamp (2)
8.2. "EMERGENCY STOP" Lamp (3)
9.2. "GENERAL ALARM" Lamp (4)
10.2. "EMERGENCY STOP" Switch (5)
11.2. "TEST" Switch (6)
12.2. "ENGINE CONTROL" Switch (7)
13.2. "LOCAL THROTTLE" Switch (8)
14.2. "CRANK OVERRIDE" Switch (9)
15.2. "MANUAL RUN/STOP" Switch (10)
16.2. "LOW IDLE" Switch (11)
17.2. "ENGINE PRTN OVERRIDE" Switch (12)
18.2. "PRELUBE OVERRIDE" Switch (13)
19.2. "MANUAL PRELUBE" Switch (14)
20.1. Data Link Features
21.2. Cat Data Link
22.2. Global CAN Data Links (Engine)
23.2. Local CAN Data Link (Engine)
24.1. Engine State Control
25.1. Air Shutoff System

Controllers

This engine is designed for electronic control of most engine operating functions. The Engine Management System (EMS) provides this control. The EMS is made up of a network of electronic controllers. These controllers communicate through the data link network to share information that is related to the operation of the engine. The EMS also provides information to external devices, such as the operator display panel. The electronic system consists of the control modules that make up the EMS, the wiring harness, switches, sensors, and fuel injectors. The control modules receive information from the sensors and the switches on the engine. The information is shared over the data link. This information is then processed in order to provide engine control. Refer to Troubleshooting, "Data Link Features" for an overview of the data links for this engine.

Primary and Secondary Electronic Control Module (ECM)



Illustration 1g01496913
Engine ECM

The engine ECM consists of two main components, the control computer (hardware) and the flash file (software). The control computer consists of a microprocessor and electronic circuitry. The flash file contains the engine operational characteristics. The operating maps that influence the engine performance are also contained in the flash file.

The engine ECM provides engine control by altering the signal that is sent to the fuel injector solenoids. By controlling the signal timing and duration, the engine ECM controls the engine speed and the engine power.

The engine ECM provides control for various subsystem components. The following subsystem components are controlled by the engine ECM:

  • Air shutoff system

  • Engine prelube system

  • System for engine cranking

  • Fuel system

  • Various other components

The engine ECM also collects data in order to provide information on various aspects of engine operation.

Redundant Engine Control Feature

This engine is equipped with a redundant engine control system. The engine incorporated dual ECM engine operation to provide for this redundancy. In a dual ECM engine operation, the primary ECM controls the engine operation majority of the time. The secondary ECM takes over control of the engine from the primary ECM to provide for the redundancy feature.

The primary ECM periodically broadcasts a message over the CAN data link and CDL Data Links that communicates the condition of the primary ECM. This message is recognized by the secondary ECM as an ECM heartbeat status of the primary ECM. If the heartbeat message is lost or unreadable, the secondary ECM will assume control of the engine.

The secondary ECM continuously transmits a ready status message over the CAN data link and CDL Data Links. As long as the secondary ECM is broadcasting a status of "Ready", the secondary ECM is eligible to take control of the engine.

Control Assembly



Illustration 2g02541156
Control assembly

The control assembly is located inside the ECM enclosure.

The injector solenoid outputs from the primary ECM and the secondary ECM are spliced together inside the control assembly. Between each ECM output and the splice, a rectifier diode is wired in series. The diodes isolate the outputs from each other. The diodes are located inside the control assembly.

Note: The internal components of the control assembly are not serviceable.

Exhaust Temperature Module



Illustration 3g01497914
Exhaust temperature module

The exhaust temperature module receives the signals from the exhaust temperature sensors. These sensors are located at each of the cylinder exhaust ports. The exhaust port temperatures are monitored by the ECM.

The exhaust port temperatures and the diagnostic information are also transmitted via the global CAN data link. Any of the display panels that are on the network can be used in order to display this information. The exhaust port temperatures can be monitored on the display panel.

Local Engine Control Panel (LEC Panel)



Illustration 4g03368235
Front of the control panel
(1) Direct control unit panel (DCU panel)
(2) "READY TO START" lamp
(3) "EMERGENCY STOP" lamp
(4) "GENERAL ALARM" lamp
(5) "EMERGENCY STOP" switch
(6) "TEST" switch for the panel lamps
(7) "ENGINE CONTROL" switch


Illustration 5g03367772
Switches on the inside panel of the control panel
(8) "LOCAL THROTTLE" switch
(9) "CRANK OVERRIDE" switch
(10) "MANUAL RUN/STOP" switch
(11) "LOW IDLE" switch
(12) "ENGINE PRTN OVERRIDE" switch
(13) "PRELUBE OVERRIDE" switch
(14) "MANUAL PRELUBE" switch

"READY TO START" Lamp (2)

The "READY TO START" lamp is illuminated when none of the following conditions exist:

  • Faults on the engine control input are present.

  • The starting air pressure is outside of operating limits.

  • Faults exist on the starter relay.

  • The barring device is engaged.

  • Level 3 events are active.

  • Emergency stops are engaged.

  • The air shutoff is active.

"EMERGENCY STOP" Lamp (3)

The "EMERGENCY STOP" lamp will illuminate when an engine shutdown occurs due to an emergency stop condition.

"GENERAL ALARM" Lamp (4)

The "GENERAL ALARM" lamp will illuminate when an alarm is active.

"EMERGENCY STOP" Switch (5)

Use the "EMERGENCY STOP" switch ONLY in an emergency situation. DO NOT use the "EMERGENCY STOP" switch for normal engine stopping. After an emergency stop, DO NOT start the engine until the problem that caused the emergency stop has been corrected.

"TEST" Switch (6)

The "TEST" switch is a momentary push switch. Activation of the "TEST" switch activates all of the lamps on the door of the panel. Activation of the "TEST" switch tests the"GENERAL ALARM" relay and the "READY TO START" relay.

"ENGINE CONTROL" Switch (7)

OFF/RESET - When the "ENGINE CONTROL" switch is in the OFF/RESET position, all alarms, safety shutdowns, and emergency shutdowns are reset. If the switch remains in this position, all electronics will enter a power-saving mode.

LOCAL - When the "ENGINE CONTROL" switch is in the LOCAL position, the controls are active and are in LOCAL mode. All remote engine controls are disabled. The engine may only be started and stopped locally from the DCU controller. The following switches inside of the door panel are operable: "LOW IDLE", "PRELUBE OVERRIDE", "CRANK OVERRIDE", "ENGINE PROTECTION OVERRIDE" and "MANUAL START/STOP".

REMOTE - When the "ENGINE CONTROL" switch is in the REMOTE position, the controls on the LEC panel are disabled except for the "EMERGENCY STOP" switch. The remote input capabilities of the DCU are activated.

"LOCAL THROTTLE" Switch (8)

The "LOCAL THROTTLE" switch is only active when the "ENGINE CONTROL" switch is in the LOCAL position and 0-5V is selected in the software.

"CRANK OVERRIDE" Switch (9)

Note: Do not use the "CRANK OVERRIDE" switch for normal engine operation. The starting motor may turn during engine operation which may damage the starting motor and the engine flywheel teeth.

The "CRANK OVERRIDE" switch is a two position switch and is only operational when the "ENGINE CONTROL" switch is in the LOCAL position. The operator may use the "CRANK OVERRIDE" switch to crank the engine with the engine starting motor when the engine control unit has completed the cycle crank sequence. The "CRANK OVERRIDE" switch is intended for use in system troubleshooting and engine maintenance. The switch can also be used to start the engine in an emergency when the engine control unit fails to crank the engine or when the primary engine control unit has failed and the engine is to be started with the secondary engine control unit.

"MANUAL RUN/STOP" Switch (10)

The "MANUAL RUN/STOP" switch is a three position momentary toggle switch which automatically returns to the center position when not in use. The switch is only operational when the "ENGINE CONTROL" is in the LOCAL position. The "MANUAL RUN/STOP" switch may be used to start or stop the engine if the DCU fails. Do not operate the engine with this switch unless the DCU has failed.

"LOW IDLE" Switch (11)

The "LOW IDLE" switch is only operational when the "ENGINE CONTROL" switch is in LOCAL mode. Activating the "LOW IDLE" switch reduces the engine speed to low idle.

"ENGINE PRTN OVERRIDE" Switch (12)

When the "ENGINE PRTN OVERRIDE" switch is activated, the engine protection that is provided by the engine monitoring system is ignored. If a diagnostic condition that requires an engine shutdown is detected monitoring system, the engine ECM will ignore the shutdown request. The use of the "ENGINE PRTN OVERRIDE" switch to operate an engine with an active fault code may cause the engine to be seriously damaged or destroyed.

"PRELUBE OVERRIDE" Switch (13)

The "PRELUBE OVERRIDE" switch is a two position switch and is only operational when the "ENGINE CONTROL" switch is in the LOCAL position. The "PRELUBE OVERRIDE" switch allows the operator to override the prelube pump sequence at the beginning of the engine crank sequence during engine start-up. Use the "PRELUBE OVERRIDE" switch for troubleshooting and to provide for immediate engine starting during emergency situations.

"MANUAL PRELUBE" Switch (14)

The switch "MANUAL PRELUBE" is used to initiate a manual prelubrication. The "MANUAL PRELUBE" switch is only operational when the "ENGINE CONTROL SWITCH" is in the LOCAL position.

Data Link Features



Illustration 6g03376473
Configuration of the data links for the C280 engines
(1) Secondary engine ECM
(2) Control assembly
(3) Primary engine ECM
(4) Global 1 CAN data link (primary ECM)
(5) Global 2 CAN data link (secondary ECM)
(6) Cat Data Link
(7) Local CAN data link
(8) Exhaust temperature module
(9) Service tool connectors for Cat ET
(10) Local engine control panel

The data links for C280 engines provide communication among the various controllers on the engine. These data links also provide communications with engine supervisory systems that are not located on the engine.

Cat Data Link

This data link is exclusively used for communications between the engine ECM and Cat ET. The functionality of the service tool will be limited if dual data link communication is not established during sessions with Cat ET. Dual-data-link-communications utilizes the Cat Data Link and the global CAN data link during communications with Cat ET.

Global CAN Data Links (Engine)

The global CAN data links allows communication with the following control systems and engine supervisory systems that are not located on the engine:

  • Engine ECMs

  • Exhaust temperature module

  • DCU

  • Service tool connector that is located on the generator set package

Note: Some service tool connectors may not provide a global CAN data link for Cat ET. The functionality of the service tool will be limited if Cat ET is not using dual data link communication. Also, if Cat ET is not connected to a service tool connector that is connected to the global CAN data link, functionality will be limited.

Local CAN Data Link (Engine)

The local CAN data link allows communication with the following control systems and engine supervisory systems that are located on the engine:

  • Engine ECMs

  • Service tool connector that is located on the engine

Note: Some service tool connectors may not provide a global CAN data link for Cat ET. The functionality of the service tool will be limited if Cat ET is not using dual data link communication. Also, if Cat ET is not connected to a service tool connector that is connected to the global CAN data link, functionality will be limited.

Engine State Control

The engine operation is controlled by the engine state control. The engine state control defines the logical sequence of events for proper engine operation. Each state in the engine state control is defined by conditions that must be achieved by the engine or by the engine subsystem. Each engine subsystem control communicates the current state of the subsystem. The engine state control uses this information to determine the operational condition of the engine. Once the conditions are achieved, the engine is considered to be in the related state.

The desired state of the engine is communicated via the CAN data link from the ECU to the engine ECM. The actual state of the engine is communicated from the engine ECM to the ECU. The state of the engine management system can be viewed on Cat ET or on the ECU.

The engine is allowed to change states when all of the conditions for the desired state of the engine are achieved. The different states of the engine state control are described below:

Engine Stopped - In this state, the EMS is powered but the engine is stopped.

Engine Prestart - During the prestart, all engine control logic that is necessary to prepare for engine starting is completed. The following prestart conditions must be completed prior to exiting this state: prelubrication of the engine, initialization of the starting aid system and other engine starting preparations. All of the other subsystems have similar control strategies. These subsystems report to the engine state control during engine operation.

Engine Cranking - Engine cranking is between zero rpm and the engine speed which allows the engine to accelerate to engine idle after starting. During this engine state, the EMS controls the engine starting function. If the engine starting function is controlled by an external source, the EMS monitors engine speed in order to detect the completion of engine cranking.

Engine Running - The engine remains in this state while the engine is idling and while the engine is producing power.

Engine Cooldown - During the state for the engine cooldown, the engine operates at reduced speed and load to allow the engine to cool before the engine stops. This action prevents damage to engine components. The driven equipment must unload the engine before this state is initiated in order to prevent the engine from stalling.

Engine Stopping - During the state for engine stopping, the engine is not producing power. The engine is turning due to inertia from the driven equipment and the inertia from the engine after fuel injection is stopped. Control subsystems may continue operation in order to prevent engine damage. This operation will extend the life of engine components.

Engine Postrun - During engine postrun, the engine crankshaft is not turning. Actions may be taken by control subsystems in order to prevent engine damage. The engine postrun is used to extend the life of engine components. These actions may be a continuation of the actions that have been initiated in the state of engine stopping.

Air Shutoff System

The air shutoff mechanisms are closed during an emergency shutdown or during an overspeed event.

The engine is equipped with two air shutoff mechanisms. There is one air shutoff mechanism on each side of the engine. The air shutoff mechanisms are hydraulically actuated by engine oil pressure. When the solenoid valve is energized by the ECM, the air shutoff mechanisms are closed.

Position sensors are installed on the air shutoff mechanisms. These sensors allow the ECM to detect the position of the air shutoff mechanisms. The ECM can also detect the activation of the air shutoff mechanisms while the engine is running. Through control of the air shutoff mechanisms, the ECM may shut down the engine. Also, the ECM can use the air shutoff to prevent the engine from starting.