Vehicular system capable of suitably controlling engine speed and gear ratio according to battery charge state

• US 8,297,390 B2
• Filed: 04/02/2008
• Issued: 10/30/2012
• Est. Priority Date: 04/06/2007
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Asada, Tadatoshi
• Primary Examiner(s): Shriver, II, J. Allen
• Assistant Examiner(s): Coolman, Travis
• Application Number:
  US12/078,628
• Publication Number:
  US 20080246285A1
• Time in Patent Office: 1,672 Days
• Field of Search: 180/65.21, 180/65.265, 180/65.275, 180/65.28, 180/65.285, 180/65.29, 701/22
• US Class Current: 180/65.275
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2710/244 Charge state
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A vehicular system includes a battery, an engine, an electric generator that is driven by the engine to generate electric power and thereby charge the battery, a first control apparatus that controls the battery and electric generator, a drive shaft, a CVT that transmits rotation of the engine to the drive shaft, and a second control apparatus that controls the engine and CVT. Further, the first control apparatus is configured to: (1) detect charge/discharge current of the battery; (2) monitor the SOC of the battery; (3) inform, when there is a decrease in the SOC of the battery, the second control apparatus of the decrease in the SOC; (4) set a target charge current of the battery for recovering the decreased SOC; and (5) control the electric generator to increase the amount of the electric power, thereby supplying the battery with the target charge current.

Claims

1. A vehicular system comprising:

a battery;

an engine;

an electric generator that is driven by the engine to generate electric power and thereby charge the battery;

a first control apparatus that controls operations of the battery and the electric generator;

a drive shaft;

a Continuously Variable Transmission (CVT) that transmits rotation of the engine to the drive shaft at a continuously variable gear ratio;

a second control apparatus that controls operations of the engine and the CVT, wherein the first control apparatus is separated from the second control apparatus and arranged close to the battery;

an electric power steering apparatus that is powered by the battery, and

wherein the first control apparatus comprises;

means for detecting a charge/discharge current of the battery;

means for monitoring a State of Charge (SOC) of the battery based on the charge/discharge current detected by the detecting means;

means for determining, when the electric power steering apparatus is in operation, whether the battery is deteriorated, wherein

the determining means detects an internal resistance of the battery based on both the charge/discharge current and a terminal voltage of the battery when the electric power steering apparatus is in operation, and determines whether the battery is deteriorated based on the detected internal resistance of the battery;

means for informing, when there is a decrease in the SOC of the battery monitored by the monitoring means, the second control apparatus of the decrease in the SOC of the battery and informing, when the battery is determined by the determining means as being deteriorated, the second control apparatus of the deterioration of the battery;

means for setting, when there is the decrease in the SOC of the battery, a target charge current of the battery for recovering the decreased SOC of the battery, wherein the setting means sets the target charge current of the battery according to a rotational speed, a field current, and an output voltage of the electric generator; and

means for controlling the electric generator to increase the amount of the electric power generated by the electric generator, thereby supplying the battery with the target charge current set by the setting means when there is the decrease in the SOC of the battery and keeping a terminal voltage of the battery within a predetermined range when the battery is determined by the determining means as being deteriorated,

wherein upon being informed of either the decrease in the SOC of the battery or the deterioration of the battery, the second control apparatus increases both a rotational speed of the engine and the gear ratio of the CVT by amounts that are set based on either an amount of the decrease in the SOC of the battery or a degree of the deterioration of the battery,

one of the first and second control apparatus further comprises;

means for estimating, before the increase in the amount of the electric power generated by the electric generator, a power generation torque of the electric generator after the increase in the amount of the electric power, wherein

the second control apparatus corrects the set amounts of the increases in the rotational speed of the engine and the gear ratio of the CVT based on the estimated power generation torque of the electric generator, and

the estimating means estimates the power generation torque of the electric generator based on the rotational speed of the electric generator, the field current of the electric generator, and the output voltage of the electric generator.

2. The vehicular system as set forth in claim 1, wherein the second control apparatus sets both the amount of the increase in the rotational speed of the engine and the amount of the increase in the gear ratio of the CVT in proportion to either the amount of the decrease in the SOC of the battery or the degree of the deterioration of the battery.