US 7,320,311 B2
Pressure boosting common rail fuel injection apparatus and fuel injection control method therefor
Yoshinori Futonagane, Susono (Japan); Kazuhiro Omae, Atsugi (Japan); and Yoshihiro Hotta, Nagoya (Japan)
Assigned to Toyota Jidosha Kabushiki Kaisha, Toyota (Japan)
Appl. No. 10/560,105
PCT Filed Apr. 28, 2005, PCT No. PCT/IB2005/001144
§ 371(c)(1), (2), (4) Date Dec. 09, 2005,
PCT Pub. No. WO2005/106231, PCT Pub. Date Nov. 10, 2005.
Claims priority of application No. 2004-135088 (JP), filed on Apr. 30, 2004.
Prior Publication US 2006/0144367 A1, Jul. 06, 2006
Int. Cl. F02M 57/02 (2006.01)
U.S. Cl. 123—446  [123/458; 123/511] 14 Claims
OG exemplary drawing
 
1. A fuel injection control method for controlling a fuel injection characteristic of a pressure boosting common rail fuel injection apparatus, the pressure boosting common rail fuel injection apparatus including a fuel injection valve which directly injects fuel into a combustion chamber of an internal combustion engine; a common rail which stores fuel having a predetermined pressure and supplies the fuel to the fuel injection valve; and a pressure boosting device that increases the pressure of the fuel supplied to the fuel injection valve from the common rail to a predetermined boosted pressure that is higher than the predetermined pressure of the fuel in the common rail, and the pressure boosting common rail fuel injection apparatus performing boosted pressure fuel injection by operating the pressure boosting device so as to increase a fuel injection pressure of the fuel injection valve when necessary, the fuel injection control method comprising the steps of:
deciding a fuel injection amount that is an amount of fuel to be injected from the fuel injection valve according to an engine operating state when the boosted pressure fuel injection is performed; and
deciding a pressure boosting period that is defined as a time interval from when operation of the pressure boosting device is started until when the fuel injection is started, based on a relationship that is defined in advance using the decided fuel injection amount and an engine rotational speeds,
wherein when the boosted pressure fuel injection is performed, the pressure of the fuel in the common rail is controlled to a constant base rail pressure irrespective of the engine operating state, fuel injection starting time is decided based on a relationship that is defined in advance using the fuel injection amount and the engine rotational speed, and operation starting time of the pressure boosting device at which operation of the pressure boosting device is started is decided based on the decided fuel injection starting time and the pressure boosting period.