Low-loss Power Choke Coil for Automotive (Direct injection engine drive circuit coil)

What is a direct injection engine drive circuit coil?

With ever-tightening environmental regulations around the world, emission regulations for cars with internal combustion engines are becoming more stringent. In order to improve emissions performance, it is necessary for such cars to efficiently burn fuel to achieve complete combustion as much as possible. Accordingly, the direct fuel injection method that directly injects fuel at high pressure into the cylinder has been adopted to facilitate highly efficient fuel combustion. Complete combustion requires fuel to be atomized and finely injected.
For that purpose, it is indispensable for the coil used to boost the voltage of the injector drive unit of a direct injection engine to have the low loss and high withstand voltage characteristics in order to shorten its boost voltage recovery time.
In addition, more automotive ECUs are being placed in the engine compartment, increasing the integration of mechanical and electronic in-vehicle components. Moreover, this trend has created a need for automotive ECUs that can be installed in high-temperature environments under more severe vibration conditions and support larger currents.

(Direct injection engine configuration diagram)
(Direct injection ECU circuit diagram)

●Performance required for injector boost coil

  • Low-loss and high withstand voltage

  • Small size and large current
  • High vibration resistance
⇒ High efficiency of direct injection engine (shortening of boost recovery time)
⇒ ECU space saving
⇒ Installation of ECU in engine compartment and the integration of mechanical and electronic in-vehicle components

Features of Panasonic's direct injection engine drive circuit coil

●Detailed explanation of features

  1. Halved power loss and doubled high withstand voltage performance compared to conventional products through the use low-loss magnetic materials with high withstand voltage.

    Panasonic has developed new low-loss magnetic materials capable of handling large currents with a high withstand voltage based on metal composite materials using its in-house-developed metallic magnetic materials to commercialize a power choke coil with halved power loss and doubled high withstand voltage performance compared to conventional products.
    These features will contribute to the improved performance and downsizing of automotive ECUs.

    *Prerequisites: 13Ao-p, frequency 75kHz, Duty 35% triangular wave current
    *1. When using two products in parallel
    Items New product
    Conventional product (1)
    Conventional product (2)
    Loss power 1.5 W 3 W 1.5 W*1
    Withstand voltage 125 V 125 V 60 V
  2. The downsizing and the reduced number of coils required to be incorporated into ECUs due to the improved performance contribute to ECU space saving.

    The in-house-developed magnetic material and winding technology that forms the coil with high precision has enabled compactness and high performance, and the volume ratio has been reduced by 40% compared to the conventional product (1). And the number of components has been reduced compared to the conventional product (2). This contributes to ECU space saving.

  3. The product eliminates the need for anti-vibration reinforcement as part of the mounting process, reducing the use of reinforcing measures with bonding agents (adhesives).

    In conventional automotive ECU board mounting processes, reinforcement measures to fix components with bonding agents (adhesives) were necessary for ensuring the high vibration acceleration-resistant performance.
    This product employs Panasonic's original coil winding and forming technologies, which reduce the height of the terminal's pull-out position down to half compared to the company's conventional products.
    Positioning closer to the mounting circuit board have achieved excellent vibration resistant performance.
    This removes the need for anti-vibration reinforcement and contributes to the streamlining of the mounting process.

Performance and Lineup

Example of use