The Developed ECU

The following section will describe in detail the open ECU and will include the following items:

1. The engine synchronizer 2. Data acquisition.

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3. Ignition control 4. Injection control 5. Throttle control

6. Turbocharger waste gate controller 4.2.1 The engine synchronizer

In order to control the engine and send a feedback signal at a specified time by the controller, first, we have to teach the controller how to detect the exact top dead center of the firing cylinder. In addition, start reading the signal from the sensor that is installed on the engine based on a crank angle degree, CAD, an engine synchronizer module, NI 9411, is connected to the encoder which is mounted on the engine crankshaft

Figure 4.1: connecting a differential device to the NI 9411 (Image source: National Instrument NI 9411 Manual)

Figure 4.1 shows the schematic diagram of how the synchronizer, NI 9411, is connected to the ACCU encoder installed on the engine, connecting the A-signal, B-signal and Z- signal, to get the exact engine rpm and the reference cylinder, the fringing cylinder.

4.2.2 Data Acquisition

Send a feedback signal to the engine needs to obtain some data from the engine first to make the appropriated calculation and analysis, then sending the desired command. Data acquisition card is used to acquire the data from the engine such as, in-cylinder pressure, engine rpm, intake manifold pressure and temperature, valve timing, etc.

A NI PXI 6123 high speed data acquisition card with a BNC 2110 analog/digital data acquisition board are used to acquire that data from the sensors mounted on the engine.

Figure 4.2: NI PXI 6123 high speed data acquisition card and BNC 2110 analog/digital data acquisition (Image source: National Instrument NI PXI 6123 Manual)

Figure 4.2 shows the data acquisition card and the 8-channel BNC board as all the sensors are connected to the data acquisition card through the BNC board using a BNC cables. This data acquisition card is fast enough to acquire the data in 500 kHz, which gives the controller the real time signal to make the right decision.

4.2.3 The ignition control

Controlling the ignition is very critical because most automotive companies adjust the spark timing to run the engine on a point so they could achieve the maximum break torque, MBT, by taking into consideration the knock limit. To satisfy this criteria, we used a high accuracy ignition control

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system using the DRRIVEN ignition module to send the ignition command, the square wave command (TTL output module), to the ignition coil at the desired spark timing with the desired volt.

Figure 4.3. Connecting ignition coils to the driver module. (Image source: National Instrument NI PXI 6123 Manual)

Figure 4.3 shows the ESTTL module and the circuit that connect the ignition module to the engine ignition coil. This system uses a battery as the power source to simulate the power supply from the car battery. The engine synchronizer sends the accurate location of the top dead center to this loop, and this loop has a manual control to determine the start of the coil charge as well as the charging time and the discharge time based on the crank angle degree to advance or retard the spark timing regarding the test conditions. In addition, this loop is designed to control the spark timing in msec.

4.2.4 The injection module

The engine used in this research is a gasoline direct injection engine, and the injector used inside the combustion chamber to inject the fuel is a solenoid injector. The fuel injector is designed by the manufacture to respond to a certain injection profile as shown in Figure 4.4

Figure 4.4: GDI injection profile.

Figure 4.5 shows the connection between the fuel injector and the direct injection module, each module designed to control three injector; therefore, two modules used to control the four injectors because the engine used in this research is a 4-cylinders engine.

Figure 4.5. Connecting direct-injectors to the driver module (Image source: National Instrument injector driver control Manual)

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4.2.5 The throttle module

With the new technology, the electronic throttle control is used as the control system for the amount of charged air getting into the engine. This throttle has two sensors: one to control the idle, and the other to control the normal operating conditions.

A LabVIEW program is used to control the throttle; interface hardware is used between the throttle control block diagram, and the engine throttle body is a DRIVVEN throttle driver module D000017 as shown in Figure 4.6. The schematic diagram of the connections between the throttle body and the module is shown also in Figure 4.6

Figure 4.6. Module terminal connections to a single electronic throttle body (Image source: National Instrument throttle body control Manual.

4.3. Summary

The engine control module developed for this engine has full control over the main engine operating parameters such as the spark timing (start, end, and duration), the injection characteristic (start of injection, end of injection, and the injection profile), the turbocharger waste gate and the throttle control. In addition, this feedback closed loop control was developed to gather the data from the engine and use these data to adjust the spark, injection and the throttle to reduce cyclic variability in addition to maintaining the engine running at the maximum brake torque.

CHAPTER 5 IONIZATION CHARACTERISTICS TURBOCHARGED GASOLINE DIRECT INJECTION ENGINE