Bosch Corporation

Yoshihito Fujishiro

Yutaka Tanaka

Tomohiro Nakamura

Yasuo Toyoshima

Yasushi Hiratsuka

A glow plug driving control apparatus. The glow plug driving control apparatus includes a glow switchand a glow plugwhich are connected in series between a power supply and ground, and an electrical controlling unitwhich controls opening and closing of the glow switch, and that can perform energization driving of the glow plug. The glow plug driving apparatus also includes an energization path switching switchthat connects in series a stability coilin a serial connection path of the glow switchand the glow plugat the time of an energization start of the glow plug, and after the energization start, causes both the glow switchand the glow plugto return to a serial connection state between the power supply and the ground.

Glow plug driving control apparatus

The presence or absence of degradation and abnormality is determined with high reliability by measuring a resistance value of a glow plug, which is in an operating state, as a latest resistance value. A method then determines whether or not the rate of the change of the latest resistance value with respect to an initial resistance value of the glow plug exceeds a first predetermined value. The method also determines whether or not the rate of the change of the latest resistance value with respect to a last resistance value that is a resistance value of the glow plug, which has been recently measured at the time of the acquisition of the latest resistance value, exceeds a second predetermined value when the rate of change of the latest resistance value with respect to the initial resistance value of the glow plug exceeds the first predetermined value. The method determines that the glow plug is in an abnormal degradation state when the rate of the change of the latest resistance value with respect to the last resistance value exceeds the second predetermined value.

Method of diagnosing glow plug and glow plug drive control device

The accuracy in controlling the heating temperature of a glow plug and the reliability of the control operation are improved. An electronic control unitis configured such that a standard applied voltage for glow plugs-to-n is set according to the engine speed and the load conditions of the engine. In addition, a correction coefficient set in advance according to the temperature classification of the mounted glow plugs-to-n is readably stored in the electronic control unitas a correction coefficient map. By multiplying the standard applied voltage by a correction coefficient K read from the correction coefficient map and applying a voltage of the multiplication result to the glow plugs-to-n as a driving voltage through the power circuitto perform driving control, stable and reliable heating temperature control can be realized regardless of variations in the heating temperature characteristics.

Glow plug driving control method and glow plug driving control device

A glow plug is provided that can be easily determined as to whether or not it is a new article. An additional circuit formed by connecting a diode, a fuse, and an adjusting resistor in series in this order is connected in parallel to a heating element of a glow plug. The diode is provided so as to have an anode located on the positive electrode side of the heating element and a cathode located on the fuse side. In the case of a unit inspection, by applying a positive voltage for test to a heating element negative electrode connecting portion, it is possible to determine whether or not the glow plug is normal without blowing the fuse before the glow plug is used in a vehicle.

Growing community of inventors

Saitama, Japan

Yoshihito Fujishiro