Caterpillar Electronic Engines

Electronics provide more complete control over the complex combustion processes that produce engine power. We’ll explain more on the next few pages, but first take a look at the performance benefits of Caterpillar Electronic Control:

• Performance is automatically fine-tuned for fast starts, rapid acceleration, and high power output.
• Reserve power is available to easily accept additional load for hard turns, changing sea conditions, or heavily loaded nets.
• Full power is available over a range of several hundred rpm.
• Fuel economy is improved.
• Smoke is virtually eliminated.
• Emissions are drastically reduced.
• Engine speed is consistent, for smoother acceleration and cruising.
• Engine synchronization is accomplished without an add-on system.

All Cat electronically controlled engines are 100% compliant with International Maritime Organization IMO NOx regulations for the year 2000. Even stricter emissions requirements can be easily met by reprogramming engine control software.

To understand electronic control, it’s important to understand fuel injection, because engines are controlled by regulating the flow of fuel into the combustion chamber. Performance is influenced not only by the amount of fuel supplied, but also by the pressure, timing, and duration of each injection cycle.

There are several reasons why modern diesel engines use unit injector fuel systems – where each injector contains the parts needed to pressurize fuel and control injection – rather than older pump and line fuel system designs. But two major reasons are that unit injection improves fuel delivery pressure and precision.

In mechanically governed engines, the amount of fuel supplied for each injection cycle is controlled by a mechanical governor setting influenced only by engine speed and load. Mechanical Unit Injector (MUI) fuel systems in these engines develop injection pressure and determine timing by mechanical power transfer from a rotating camshaft lobe to the injector. At any given engine speed, injection timing and injection pressure are set, unchangeable values.

In Electronic Unit Injector (EUI) fuel systems, fuel injection pressure is still produced through mechanical links to the camshaft. But fuel delivery timing and injection duration are precisely controlled through electronic messages sent to the injectors. Fuel settings are infinitely variable and continuously adjusted in response to changing conditions. Factors other than engine speed and load – such as pilot’s desired engine speed, boost pressure and system temperatures – are also taken into account.

Caterpillar’s patented Hydraulically-Actuated Electronically-Controlled Unit Injector (HEUI) fuel system takes engine control one step further by adding fuel injection pressure to the list of electronically controlled variables. With HEUI, the mechanical link between injector and camshaft is eliminated. A pump and hydraulic oil manifold system provides the force required to pressurize fuel in the injector. Fuel injection rate and pressure are adjusted by the electronic control system, and higher injection pressures are available at slower engine speeds.

In both EUI and HEUI systems, the Caterpillar Electronic Control Module (ECM) functions as a busy control tower. Twenty times every second it accepts information from all engine and transmission sensors, relays data for pilothouse monitoring, and sends out engine control commands. Fuel injection timing is optimized during cold starts for less white smoke, and fuel delivery at all engine speeds is automatically balanced with available boost pressure. The results are increased engine efficiency and improved performance.

Some benefits are programmed into specific engine groups:

• Cat electronic engines from 340-1,400 bhp (253-1,044 bkW) have Slow Vessel Mode, allowing operation below low idle speed for tight maneuvering. And Trolling Mode limits engine speed to a customer-preset maximum while allowing full throttle range for precise slow-speed control.
• Bigger Cat 3500 Series B engines have a load feedback feature which allows more complete integration of engines, gears, and controllable pitch propeller systems. Future enhancements, such as automatic shifting of multi-speed gears, are also made possible.

With Caterpillar electronic control, you have instant access to vital operation information that helps you keep your engine running in top condition.

When scheduled maintenance is due, the electronic engine control module notifies you. It warns of any nonstandard operating conditions such as high coolant temperature. It allows you to select programmable engine protection strategies. And it records operation data that you can use to review operator practices, streamline troubleshooting, and speed up service.

Cat electronics help you protect your engine investment, extending both component life and engine life. For example, high exhaust temperature can be caused by dirty air cleaners, bad ventilation, engine overload, even poor maintenance practices. And it can result in anything from early valve failure to complete engine destruction.

With Cat Marine Electronic Engines, sensors keep the electronic engine control module – and you – informed of system pressures and temperatures. If the electronic engine control module senses anything abnormal, it sends a warning to the operator’s monitor and records the incident for future service technician reference. If the event is serious enough to impact engine health, and your application allows you to use programmed protection strategies, the electronic engine control module will automatically derate the engine.

Engine protection strategies are customer selectable. On engines up to 1,400 bhp (1,044 bkW), they can provide warning only, or provide a warning and derate the engine. On 3500 Series B engines, options include: warning the pilot when engine conditions approach critical limits, derating the engine according to a programmed strategy, shutting the engine down if severe damage is imminent, or allowing the pilot to keep the engine operating with a shutdown over-ride switch.

Caterpillar electronic engineers design entire marine control systems – including the electronic engine control module, wires and sensors – to stand up to the toughest marine conditions. Cat electronics are tested to resist extreme temperatures, vibrations, electric currents, magnetic fields, radio interference, and electrostatic discharges. All components are fully sealed and pressure-tested to resist contaminants, including mist with nearly 100-percent salt concentration.

The Caterpillar electronic engine control module and associated sensors are certified by all major marine classification societies. The electronic system diagnoses itself and reports any faulty wiring or sensors. If needed, it switches over to appropriate back-up sensors or program strategies.

Extensive field experience confirms what testing and certification prove: Where it counts most – keeping your engines running – you’ll find unmatched security with Cat Marine Electronic Engines.