Components for Gasoline Direct Injection Systems

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 Components for Gasoline Direct Injection Systems

                                                           In the marketplace                           The first commercial systems

  A    familiar technology
       in diesel engines, direct
  injection is beginning to
                                                           Direct injection means injecting
                                                           the fuel directly into the cylinder
                                                                                                     employed constant fuel pressure,
                                                                                                     but the industry is moving toward
                                                                                                     variable-pressure systems. Similarly,
  appear in gasoline powertrains.                          instead of premixing it with air in       multiplunger designs are giving way
  The technology requires                                  separate intake ports. That allows        to simpler, single-plunger designs in
  extremely sophisticated                                  for controlling combustion and            the high-pressure pumps. And
  engine management systems.                               emissions more precisely. But it          automakers are shifting to variable-
  DENSO supplies a large and                               demands advanced engine                   volume pumps, from constant-volume
  growing line of products for                             management technologies. Mitsubishi,      models, to accommodate their
  those systems.                                           Toyota, and Nissan have introduced        variable-pressure fuel systems.
                                                           direct injection engines for gasoline-       Each automaker adopts unique
                                                           powered vehicles, and some                spray characteristics in their high-
                                                           European automakers have introduced       pressure injectors to accommodate the
                                                           gasoline direct injection engines         combustion concept of their engines.
                                                           since 2000.                               Injectors that form a cone-shaped

                                                                                                    High-pressure fuel pump
                              High-pressure fuel line

             Fuel feed line

Fuel return line

  Fuel pressure sensor

 Common rail

Fuel pressure relief valve

 Fuel pump

                                                                    Electronic driver                                         Engine electronic
                                  High-pressure injector            unit (EDU)                                                control unit (ECU)

 I Gasoline direct injection system

spray are most common, though                          In comparison with                             Issues and outlook
Toyota has begun using a fan-shaped                    competitors
spray.                                                                                                Gasoline direct injection can help
   We began limited production of                      The low drive torque in our high-              reduce the environmental impact of
components for gasoline direct                         pressure pumps is significantly lower           internal combustion power. By 2005,
injection engines in 1996 and have                     than in competing products. And the            we expect more than 20% of the
been mass-producing them since 1997.                   single-plunger design makes the                gasoline-powered new vehicles sold
In 2000, we supplied components for                    pumps smaller and less expensive               in Japan to have direct injection.
about 120,000 gasoline direct injection                than multiplunger models.                         Reducing cost is a pressing issue in
engines. We strengthened our product                      Our slit nozzles produce the first           making direct injection available in a
line during the year by introducing                    fan-shaped spray in the automobile             broadened range of vehicle models.
lighter-weight, higher-performance                     industry. And our experience in                We will cultivate economies of scale
components.                                            mass-producing both slit and swirler           by standardizing component designs
                                                       nozzles equips us to satisfy a full            and installation methods for different
                                                       range of automakers’ needs.                    engines.
                                                          Combining components in hybrid
                                                       ICs has simplified and reduced the
                                                       size of our electronic driver units for        Technical highlights
                                                       injectors. Our units are about 40%
                                                       lighter than competing products.               Our common rail circuits allow for
                                                                                                      controlling the fuel-delivery amount
                                                                                                      to generate the fuel pressure required
                                                                                                      by the engine. Electronic control
                                                                                                      adjusts the amount of fuel delivery
                                                                                                      with reference to a fuel pressure
                                                                                                      sensor in the common rail.
                                                                                                         We use a single-plunger design in
                                                                                                      our high-pressure injection pumps to
                                                                                                      provide high volumetric efficiency at
                                                                                                      low drive torque and at low cost. Our
High-pressure pump                                     Electronic driver unit                         pumps have a built-in electromagnetic
                                                                                                      control valve, and the control function
                                         Slit nozzle                                 Swirler nozzle   varies the fuel-delivery amount by
                                                                                                      adjusting the timing of the drive
                            Front view                           Side view
                                                                                                      pulses sent to the valve. The drive
                                                                                                      torque and pulsation inside the high-
                                                                                                      pressure lines are minimal, since our
                                                                                                      pumps supply only as much fuel as
                                                                                                      the engine actually requires.
                                                                                                         Our high-pressure injectors are
                                                                                                      available with different nozzles for
                                                                                                      different spray configurations. We
                                                                                                      offer a swirler nozzle to produce a
                                                                                                      cone-shaped spray and a slit nozzle
                                                                                                      for a fan-shaped spray. Ultraprecise
                                                                                                      machining helps ensure a fine, high-
                                                                                                      quality spray. We optimize injector
                                              Fan-shaped                              Cone-shaped     performance with electronic driver
I High-pressure injection                                                                             units that incorporate original ICs.