National Instruments NI 9751 User Manual
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National Instruments NI 9751 User Manual

Direct injector driver module
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Summary of Contents for National Instruments NI 9751

  • Page 1 SHC68-68-RDIO...

  • Page 2: Table Of Contents

    USER MANUAL NI 9751 NI Powertrain Controls Direct Injector Driver Module Contents Safety Guidelines........................2 Introduction ..........................2 Pinout............................3 Hardware ..........................4 Powering the Module........................ 4 Platform Compatibility ......................6 Internal Boost Power Supply ....................7 Direct Injector Drivers......................10 Connecting Injectors to the Module ..................

  • Page 3: Safety Guidelines

    Even when the NI 9751 is completely powered off, allow approximately three minutes for the internal high voltage to dissipate. Do not touch any of the module screw terminals or injector terminals while the NI 9751 is powered on.

  • Page 4: Pinout

    Each DI driver channel is individually controlled for timing and duration, but channel operation cannot overlap. The NI 9751 cannot control piezo and solenoid actuator types simultaneously. When configured for piezo mode, channel 3 is not available and you must short the terminals together.

  • Page 5: Hardware

    The external screw terminal connector block, the terminals of which are labeled BATT (0) and GND (9). A typical power source is an automotive 12 VDC or 24 VDC battery system, but the NI 9751 can accept power from a range of 7 VDC to 32 VDC. Caution You must use a UL-listed power supply with the NI 9751.
  • Page 6 This event is not covered by warranty. The NI 9751 includes an optional power input to the external screw terminal connector block labeled EXT PWR (7). The ground reference for EXT PWR (7) must be the same ground as GND (9).

  • Page 7: Platform Compatibility

    • Maintain an ambient system operating temperature of 0 °C to 45 °C. Note Typical specifications of National Instruments modules might not apply when used in a system with NI Powertrain Control modules. Note National Instruments guarantees warranted specifications for all National Instruments modules except thermocouple modules when used in a system with NI Powertrain Control modules.

  • Page 8: Internal Boost Power Supply

    Internal Boost Power Supply The NI 9751 contains an internal boost power supply that can maintain a voltage level from battery voltage up to 190 V. You can use software to enable or disable boost power supply at any time. The internal booster power supply is disabled automatically whenever critical faults occur and can only be enabled by clearing the faults.
  • Page 9 Power Supply Overload Fault (PSOverLoad) The NI 9751 maintains an integrator of power supply usage. An internal counter increments with each power supply voltage boost and decrements according to a fixed time interval. If the integrator winds up to 148,480 counts, an overload fault is set.
  • Page 10 Due to the C Series module housing design, there is limited ability for heat to escape. The primary source of heat within the NI 9751 is the internal boost power supply. If the internal module temperature rises above approximately 80 °C, the module temperature fault is set.

  • Page 11: Direct Injector Drivers

    Direct Injector Drivers Injector Driver Circuit Description The NI 9751 contains three solenoid DI drivers and can drive two Piezo injectors. The driver channels share some circuitry, so injection events cannot overlap among channels within the same module. If injection events with different injectors must overlap, you must use multiple modules.
  • Page 12 A dual comparator feedback circuit for upper and lower dithering thresholds controls the solenoid current. Other current- and voltage- sensing circuits are used for fault detection. NI 9751 User Manual | © National Instruments | 11...
  • Page 13 Figure 2. Solenoid IPhaseArray Configuration Example 1 Figure 3. Current and Voltage Traces from Solenoid IPhaseArray Configuration Example 1 Figure 4. Solenoid IPhaseArray Configuration Example 2 12 | ni.com | NI 9751 User Manual...
  • Page 14 Figure 5. Current and Voltage Traces from Solenoid IPhaseArray Configuration Example 2 Figure 6. Solenoid IPhaseArray Configuration Example 3 Figure 7. Current and Voltage Traces from Solenoid IPhaseArray Configuration Example 3 NI 9751 User Manual | © National Instruments | 13...
  • Page 15 IUpper threshold, as shown in Figure 10. Figure 10. Current and Voltage Traces from Phase1FirstPeakEnable=TRUE Operating Mode 14 | ni.com | NI 9751 User Manual...
  • Page 16 BackBoostTime. Figures 11 through 15 show different values for BackBoostTime applied to the same solenoid injector. Figure 11. BackBoostTime = 0.0 ms Figure 12. BackBoostTime = 0.025 ms NI 9751 User Manual | © National Instruments | 15...
  • Page 17 Figure 13. BackBoostTime = 0.050 ms Figure 14. BackBoostTime = 0.100 ms Figure 15. BackBoostTime = 0.150 ms 16 | ni.com | NI 9751 User Manual...
  • Page 18 Piezo Injector Operation The NI 9751 can of drive unipolar piezo injectors. Unipolar means the piezo injector is charged to a positive voltage and discharged to ground. Bipolar drive means the piezo injector can be charged to a positive or negative voltage. Channels 1 and 2 are viable for driving piezo injectors.
  • Page 19 Power Supply High-Side, High-Voltage Switch 47 µH 47 µH Short Inductor Inductor Piezo Piezo Injector 1 Injector 2 – – – Low-Side Low-Side Low-Side Switch Switch Switch Current Sense & Comparator Circuitry 18 | ni.com | NI 9751 User Manual...
  • Page 20 The NI 9751 can also operate inverted charge scheme piezo injectors. The PiezoInvert Boolean determines the inverted piezo mode. The injector valve closes when the stack is charged and the valve opens when the stack is discharged. Channel 1 can operate only a single piezo injector when operated in inverted mode.You must leave Channel 2 disconnected and connect Channel 3...
  • Page 21 Figure 18. Piezo IPhaseArray Configuration Example 1 Figure 19. Current and Voltage Traces From Piezo IPhaseArray Configuration Example 1 HVTarget = 150 V. Charge time = 148 μs. Figure 20. Piezo IPhaseArray Configuration Example 2 20 | ni.com | NI 9751 User Manual...
  • Page 22 HVTarget = 150 V. Charge time = 124 μs. Figure 22. Piezo IPhaseArray Configuration Example 3 Figure 23. Current and Voltage Traces from Piezo IPhaseArray Configuration example 3 HVTarget = 150 V. Charge time = 188 μs. NI 9751 User Manual | © National Instruments | 21...
  • Page 23 Figure 24. Piezo IPhaseArray Configuration Example 4 Figure 25. Current and Voltage Traces from Piezo IPhaseArray Configuration Example 4 HVTarget = 150 V. Charge voltage = 100 V. Figure 26. Piezo IPhaseArray Configuration Example 5 22 | ni.com | NI 9751 User Manual...
  • Page 24 HVTarget = 150 V. Charge voltage = 100 V step, then 150 V. Figure 28. Piezo IPhaseArray Configuration Example 6 Figure 29. Current and Voltage Traces from Piezo IPhaseArray Configuration Example 6 HVTarget = 150 V. Inverted piezo operation. NI 9751 User Manual | © National Instruments | 23...
  • Page 25 Because current is flowing through the injector solenoid, the load inductance limits current rise times and the NI 9751 typically detects the short at about 20 A if the channel is off and 45 A if the channel is on.

  • Page 26: Connecting Injectors To The Module

    INJ- shorted to battery—This condition immediately causes a ShortCircuit critical fault. Because current is bypassing the injector solenoid, current rise times are extremely fast and can peak as high as 200 A before detection. However, the NI 9751 can handle this current spike and shut down appropriately.

  • Page 27: Specifications

    Figure 33 illustrates connecting piezoelectric injectors to your NI 9751. Figure 33. Connecting Piezoelectric Injectors to the NI 9751 UL Listed 20 A Automotive Fuse BATT INJ1– – INJ1+ Piezo Injector – INJ2– INJ2+ Piezo – – Injector 12 V to 24 V INJ3–...
  • Page 28 If the current during an injection command does not exceed this level, the module reports an Open Circuit Fault. This does not affect the operation of the driver and is for information only. NI 9751 User Manual | © National Instruments | 27...
  • Page 29 NI recognizes that eliminating certain hazardous substances from our products is beneficial to the environment and to NI customers. For additional environmental information, refer to the Minimize Our Environmental Impact web page at . This page contains the environmental regulations and ni.com/environment 28 | ni.com | NI 9751 User Manual...

  • Page 30: Where To Go For Support

    NI product. Refer to the Export Compliance Information at ni.com/legal/export-compliance for the National Instruments global trade compliance policy and how to obtain relevant HTS codes, ECCNs, and other import/export data. © 2013 National Instruments. All rights reserved.

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