ENGINE STARTING APPARATUS WITH INRUSH CURRENT REDUCER

• US 20150354523A1
• Filed: 06/01/2015
• Published: 12/10/2015
• Est. Priority Date: 06/04/2014
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: HIRABAYASHI, Takashi
• Granted Patent: US 9,771,915 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02N 11/0851 characterised by means for controlling the engagement or disengagement between engine and starter, e.g. meshing of pinion and engine gear
• CPC Class Codes: F02N 11/087 Details of the switching means in starting circuits, e.g. relays or electronic switches
• CPC Class Codes: F02N 15/023 of the overrunning type
• CPC Class Codes: F02N 15/046 of the planetary type
• CPC Class Codes: F02N 15/067 the starter comprising an electro-magnetically actuated lever
• CPC Class Codes: F02N 2015/061 said axial displacement being limited, e.g. by using a stopper
• CPC Class Codes: F02N 2200/023 Engine temperature
• CPC Class Codes: F02N 2200/044 Starter current
• CPC Class Codes: F02N 2300/102 Control of the starter motor speed; Control of the engine speed during cranking
• CPC Class Codes: F02N 2300/104 Control of the starter motor torque
• CPC Class Codes: F02N 2300/2011 Control involving a delay; Control involving a waiting period before engine stop or engine start

Abstract

An engine starting apparatus is provided which is equipped with a starter, an inrush current reducer, and a starter mode switch. The inrush current reducer works to reduce an inrush current flowing through an electric motor installed in the starter when the electric motor is energized. The starter mode switch works to change a starter characteristic that is an output characteristic of the starter continuously or selectively at least between a low-torque/high-speed mode and a high-torque/low-speed mode. The starter mode switch places the starter in the high-torque/low-speed mode at least at a time when a piston of the engine is passing a top dead center, and the engine friction has been just maximized for the first time after the starter is actuated to crank the engine. This shortens a period of time required to start up the engine without sacrificing beneficial effects offered by the inrush current reducer.

Claims

1. An engine starting apparatus for an engine comprising:

a starter which works to start an engine using torque, as produced by an electric motor;

an inrush current reducer which works to reduce an inrush current flowing through the electric motor when energized; and

a starter mode switch which works to change a starter characteristic that is an output characteristic of the starter continuously or selectively at least between a low-torque/high-speed mode and a high-torque/low-speed mode, the starter mode switch placing the starter in the high-torque/low-speed mode at least at a time when a piston of an engine is passing a top dead center, and an engine friction has just been maximized for the first time after the starter is actuated to crank the engine.

2. An engine starting apparatus as set forth in claim 1, wherein the starter characteristic used when the piston of the engine passes the top dead center for the first time after the starter is actuated is determined so that a value of current flowing in the electric motor when the piston of the engine passes the top dead center for the first time is lower than a value of the inrush current flowing in the electric motor reduced by the inrush current reducer.

3. An engine starting apparatus as set forth in claim 1, wherein the starter characteristic used when the piston of the engine passes the top dead center for the first time after the starter is actuated is provided to exhibit a highest-torque/lowest-speed characteristic of the starter.

4. An engine starting apparatus as set forth in claim 1, wherein a switching time that is a time when the starter characteristic is switched from the high-torque/low-speed mode to the low-torque/high-speed mode is provided as being a time after the piston has passed the top dead center for the first time by determining a time interval between start of operation of the starter and the switching time using a timer function.

5. An engine starting apparatus as set forth in claim 1, wherein the electric motor is a brushed DC motor.

6. An engine starting apparatus as set forth in claim 1, wherein a switching time that is a time when the starter characteristic is switched from the high-torque/low-speed mode to the low-torque/high-speed mode is set to a preselected fixed value.

7. An engine starting apparatus as set forth in claim 1, wherein a switching time that is a time when the starter characteristic is switched from the high-torque/low-speed mode to the low-torque/high-speed mode is deter mined as a function of an amount of charge in an electric power source which supplies an electric power to the electric motor of the starter.

8. An engine starting apparatus as set forth in claim 1, wherein a switching time that is a time when the starter characteristic is switched from the high-torque/low-speed mode to the low-torque/high-speed mode is determined as a function of a temperature of coolant for the engine.