Automotive test engineers and technicians are constantly required to perform tests of new model engines and their components. Many years ago, before the introduction of electronic engine controllers and electronic engine components, testing was limited to starting the engine, controlling it, and taking measurements or making observations. With the introduction of electronic injectors and ignition systems, along with electronic engine controllers, an additional level of complexity was introduced which required adaptations to facilitate testing. These adaptations took the form of either modifying the programming of the OEM controller, or using a programmable third party controller to suit the testing requirements.

 OEM controller modifications have always been difficult, and is becoming increasingly more difficult, as the controller's programming and functionality become more complex. Third party controllers such as the old IC 5460, and more modern programmable generic electronic engine controllers have found a niche, but have limitations. These limitations included the use of custom harnesses, custom written startup and steady state strategies, and the use of non-OEM components.

Today's engine testing is becoming more complex with the introduction of electronic valve control, drive by wire technology, and the increased reliance on additional electronic components and modules. To facilitate these complexities, the EMAS (Engine Management and Analysis System) II has been created.

The EMAS II was created to be a tool used by test engineers and technicians to facilitate engine testing. To be a useful tool, certain features had to be built into the EMAS II, these features include:

• The ability to work with OEM controllers
• The use of OEM equipment and harnesses.
• The ability to interface many if not all engines. 

OEM controller compatibility:

The defining feature of the EMAS II is its ability to work with an OEM engine controller. This capability allows the stock OEM engine to retain all of its original equipment without substitutions or modifications. This allows the drive-by-wire technology, electronic valve control, and all the timing and control strategies, which teams of programmers have developed, to be used instead of constantly recreating portions of them. Depending on the type of testing being performed, usually only a few of the engine's control parameters need to be altered. If, for example, the air fuel ratio needed to be altered, there is no need to alter the valve or ignition timing to accomplish the test. The EMAS II allows the user the ability to control specific sub-systems while leaving the remaining systems under the control of the OEMs controller.

OEM equipment and harness:

To perform testing on an engine or engine component it is usually a requirement to have the OEM's sub-systems and controller present. After all, the purpose of the test is usually to test the OEM system, not third party components, which will not be present in production. For example, if one were to replace the ignition coils or injectors while the test was checking on the engine emissions, the results could be invalid because the emissions may have been different had the OEM sub-systems not been replaced.

In addition, the use of the OEM harnesses takes advantage of shielding and other EMI considerations, which the OEM spent time developing. Using a third party harness results in great difficulties with connectors, EMI considerations, debugging, and generating and maintaining new documentation. Using an OEM harness eliminates all of these difficulties. 

The EMAS II is designed specifically to use the existing OEM sub-systems and harnesses. 

Interfacing to various engines:

With the emphasis on reducing time of development, test engineers are under additional pressure to perform a test quickly and efficiently. Since various sub-systems need to be tested on various engine platforms, the group responsible for testing must have the ability to test different engine platforms and sub-systems. This includes various OEM engine controllers such as Fords 104 or 150 pin engine controllers. The testing may also include benchmarking tests or competitive analysis testing of a competitors engine, which requires a quick and simple interface to the engine. Therefore, the EMAS II had to have the ability to quickly interface to various engine platforms.

Design Philosophy:

The EMAS II addresses the changing needs of the auto industry and takes advantage of years of experience with engine controllers and test cell operations. The EMAS II is a tool which allows for engine control, data acquisition, and control of various devices found in a test cell.

The EMAS II is designed to be located in the test cell- near the engine. The proximity of the controller to the engine provides:

·   Minimized EMI

·   Ease of installation

·   Greatly reduced wiring

An important issue facing any electronic system located in the engine cell is susceptibility to Electromagnetic Interference (EMI). This noise can distort the electronic signals traveling along the wiring harnesses between the engine and engine controller causing the engine to malfunction or erratic data to be recorded. The longer the harness is, the greater the propensity for noise related problems.

The EMAS II relieves these problems in the following ways. First, the EMAS II resides next to the engine minimizing harness lengths. Second, the breakout box is integrated into the EMAS II, minimizing the distance between the breakout box and injector/ignition controller modules. Third, each wire inside the breakout box and within the external harnesses is individually shielded. Fourth, the EMAS II uses differential inputs and optically isolates all digital and analog I/O signals. Finally, the EMAS II communication links travel via fiber optic cable which is immune to EMI. This design minimizes the opportunity for EMI to interfere with system operations and your test execution.

Another advantage of the EMAS II's design is ease of installation. No longer do you have to route bulky engine control and sensor cables from the engine cell to the control room. All of these signals can be digitized by the EMAS II and transmitted to the control room with fiber optic cables. The EMAS II, shown to the left, is modularized which allows additional modules to be stacked on the unit or distributed throughout an engine test cell. These modules are specific to certain tasks such as injector control, ignition control, relay/power control, transmission control, or cell related functions such as dynamometer control, throttle control, temperature sensors or various control loops. 

What we have developed is a parallel processor based design which is geared toward engine and test cell control. Our goal is to have distributed processing located throughout a test cell which will digitize the data as close to its source as possible while sharing the data at very high speeds.

Description of the EMAS II

The EMAS II is comprised of stacked hexagonal modules. The top module, Injector Control, can manage up to 12 injectors and contains six expansion slots. These expansion slots allow you to customize the system to meet your specific needs.

(See the Expansion Card list, below.)

The next module, Ignition Control, similarly manages 12 ignition coils and contains six expansion slots. 

Continuing down the stack we come to the heXalink®, a 200-pin generic breakout box. (NOTE: a 300-pin model is available.) The function of a breakout box is to allow the user to selectively break signals between the engine and engine controller. The signal is broken by the simple throw of a switch. Once the signal is broken, a wire is used to carry the broken connection to the appropriate module. For example, the injectors may be broken and sent up to the Injector Control Module. The EMAS II can then take control of the injector coils. However, the EMAS II has the unique ability to automatically reconnect broken injector or ignition coil connections. This capability allows you to automatically switch fueling and ignition control between the engine controller and EMAS II at any point(s) during your test. 

The next module is the Power Relay Module. It contains AC input filters, fuses, blower controls, system temperature monitors, power supplies, and various relays for controlling external equipment. 

Finally, the Blower Module is designed to keep the EMAS II cool in the environment of an engine test cell. For ease of movement, all of these modules mount to a vibration absorbing, tip-resistant wheelbase.

Figure 3 above shows the flow-chart diagram illustrating how the EMAS II is interfaced to the engine and the host PC.

Notice that the engine controller is used by the EMAS II. Although the EMAS II will soon be able to control the engine without an engine controller, the EMAS II is designed to learn the engine controller's fueling/ignition firing order and timing, eliminating the need to program this information.

Interfacing Procedures:

To interface an EMAS II requires three steps:

1. The EMAS II must be interfaced to the test engine. This is accomplished by using the integrated breakout box with the engine controller/harness adapter appropriate for your engine and engine controller.
2. The correct signals must be broken on the breakout box and routed from the breakout box to the appropriate control modules on the EMAS II. This is simply a matter of plugging banana jack cables into the breakout box and connecting the signal to the appropriate EMAS II receptacle.
3. The EMAS II must be interfaced to a PC(s) containing a fiber optic card. Due to environmental conditions within the engine cell, it is highly recommended that these PCs be located in the control room. This interface requires two fiber optic cables to be run from the test cell into the control room.

Test routines are written by our program generator or custom routines can be written in most programming languages (e.g. C, C++, Visual C, Visual Basic, etc.)

PC Interface

As seen in figure 3 above, the EMAS II is linked to a PC via a fiber optic cable. The information transmitted across this fiber optic link is in a proprietary format to maximize data throughput. All the EMAS II modules look to the fiber optic card for message passing, data transmission, and communications, making the PC an integral part of the EMAS II data loop. The EMAS II can be configured with 2 PC(s): one PC to be used as a GUI (graphic user interface) controller, while the second is used for data logging, report generation, and signal analysis. It is worthwhile noting that the EMAS II will function with a single PC, however user interface response can degrade if a slow PC is used while networking options, waveform analysis, data distillation, data downloading or report generation functions are occurring simultaneously.

The current list of expansion cards include:

Signal Modification Card:

This card comes standard with the EMAS II. It is designed to accept up to 4 signals and allow the user to modify the original signals. The user can shift the input voltage with a bias either up or down, or as is more common, replace the real signal with a simulated signal. This last feature is used in our catalyst aging software during the time when the EMAS II is supposed to be in control of the fuel injection. To accomplish this, the OEM engine controller must be oblivious to the changes in AFR, therefore a simulated EGO signal is generated and sent to the OEM controller, instead of the real EGO signal.

The card also digitizes the signals the signals coming into and going out of the card.

Sensor Interface Card:

This card contains 8 differential analog input channels, which accept signals from 0 to 10V. These are currently used by our catalyst aging software to record conditioned thermocouple outputs which have been normalized to read 0-10V over a 1000-2000 deg F range, along with recording the throttle position, mass air, and battery voltage. This card is also standard with the EMAS II when configured for catalyst aging.

TC/Position Card:

This card has 8 thermocouple inputs, which are used to record temperatures from thermocouples that have not been conditioned or normalized. In addition, some of the thermocouple channels can be sacrificed and converted into CAM and Crank position inputs to help measure and control ignition and/or value timing. This card comes standard with the catalyst-aging package.

The EMAS II can trace its roots back to the late 80's when its predecessor called an ECAS (Engine Catalyst Aging System) was developed for Ford Motor Company and its suppliers to be used in the area of catalyst aging. The original ECAS was designed to work with the OEM engine controller as part of the aging test. Since that time, many advancements in engine technology have occurred and the EMAS II has been developed to meet these changes.

Since we manufacture the EMAS II, we have the ability to customize it quickly and easily. One example of how this tool was customized can be found in the area of catalyst aging and evaluation.

The EMAS II is designed to be generic and some customization may be necessary depending on the type of testing being performed. Generally, an EMAS II offers the user a quick and efficient method to run a stock engine with harness, OEM engine controller, and OEM sub-systems.