Exhaust gas-driven generator system and method of controlling electrical system

• US 20060113799A1
• Filed: 09/22/2005
• Published: 06/01/2006
• Est. Priority Date: 12/01/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Fujitsuna, Masami, Obayashi, Kazuyoshi, Tamura, Hiroshi, Tani, Keisuke
• Granted Patent: US 7,432,609 B2
• Time in Patent Office: Days
• US Class Current: 290/40.B
• CPC Class Codes: F01N 5/04 the devices using kinetic energy
• CPC Class Codes: F02B 37/005 Exhaust driven pumps being combined with an exhaust driven auxiliary apparatus, e.g. a ventilator
• CPC Class Codes: F02D 29/06 peculiar to engines driving electric generators
• CPC Class Codes: F02D 41/021 Introducing corrections for particular conditions exterior to the engine conjoint control of vehicle sub-units for propelling the vehicle B60W30/18
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: H02J 7/143 with multiple generators
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An amount of electric power generatable by an exhaust gas-driven rotating electric machine is determined corresponding to an operating point, so that an increment amount of fuel by the exhaust gas-driven electric power generation is smaller than engine-driven alternator power generation. The power generation can be thereby performed by effectively utilizing exhaust energy of the engine.

Claims

1. A generator system comprising:

a generator that performs power generation by utilizing drive forces of an engine;

an exhaust gas-driven generator that performs power generation by utilizing exhaust gas energy of the engine; and

a generatable amount determination means that makes a determination of a generatable amount of power in correspondence to an operating point of the engine, the generatable amount of power indicating an amount of electric power generatable by the exhaust gas-driven generator with an increment amount of fuel being smaller than an increment amount of fuel for the engine necessary for the power generation by the generator.

2. The generator system according to claim 1, further comprising:

engine control means that performs control of the engine based on the generatable amount of power determined by the generatable amount determination means.

3. The generator system according to claim 1, wherein the generatable amount determination means makes the determination so that as an output of the engine is higher, the generatable amount of power increases.

4. The generator system according to claim 1, further comprising:

a power bus connected to the generator and loads; and

disconnecting means that disconnects connection between the exhaust gas-driven generator and the power bus when control of the exhaust gas-driven generator is disabled.

5. The generator system according to claim 1, further comprising:

generator control means that performs control of the generator;

exhaust gas-driven generation control means that performs control of the exhaust gas-driven generator; and

instructing means that issues commands to the generator control means and the exhaust gas-driven generation control means,

wherein the generator control means and the exhaust gas-driven generation control means each perform the control in accordance with a voltage command for the power bus from the instructing means.

6. The generator system according to claim 4, wherein the generatable amount determination means reduces the generatable amount of power, when a voltage level of the power bus exceeds a predetermined level.

7. The generator system according to claim 2, wherein the engine control means performs the control by adding a loss of output torque to an output torque command for the engine in order to compensate for the loss of output torque of the engine in an event where the exhaust gas-driven generator generates the generatable amount of power.

8. A method of controlling an electrical system that performs power supply to an electrical load and a battery from a plurality of power energy supply sources including an exhaust gas-driven generator that performs power generation by utilizing exhaust energy of an engine and a generator that performs power generation by utilizing drive forces of the engine, the method comprising the steps of:

calculating information of power costs each coinciding with a cost per unit amount of electric power of respective one of the power energy supply sources and suppliable amounts of power of the respective power energy supply sources;

adjusting power supply allocation ratios of the power energy supply sources and a received power allocation ratio of the electrical load or a battery in accordance with the information in a direction along which the power energy is reduced,

wherein for the exhaust gas-driven generator, a generatable amount of power indicating an amount of power generatable by the exhaust gas-driven generator, the amount of power being determined corresponding to an operating point of the engine, is used as the suppliable amount of power; and

wherein an increment amount of fuel for the engine which increment amount is necessary for generation of the suppliable amount of power is used as the power cost.

9. The method of controlling an electrical system according to claim 8, wherein the increment amount of fuel is an amount of fuel to be increased to obtain an output torque of the engine that is substantially the same as that in the event that power generation is not performed in the event that the generatable amount of power is generated by the exhaust gas-driven generator.

10. The method of controlling an electrical system according to claim 9, wherein the increment amount of fuel is calculated by using a map or a model, the map indicating a relationship between the generatable amount of power and the increment amount of fuel.

11. A generator system for an engine having a turbocharger, the system comprising:

a battery;

a power bus connecting the battery to a load;

an engine-driven generator driven by the engine and connected to the power bus for generating electric power which is supplied to the battery and the load through the power bus;

an exhaust gas-driven generator coupled to the turbocharger for generating electric power by utilizing exhaust gas energy of the engine; and

a control unit programmed to

detect an operating point of the engine and a voltage of the power bus,

determine an amount of electric power that can be generated by the exhaust gas-driven generator based on a detected operating point of the engine,

determine an amount of loss of toque of the engine, which is caused by power generation of the exhaust gas-driven generator, based on a determined amount of electric power and a detected voltage of the power bus, and

control the engine by supplying additional fuel which compensates for a determined loss of torque of the engine.

12. The generator system according to claim 11, wherein the control unit gradually decreases the determined amount of loss of the torque when the detected voltage of the power bus is higher than a predetermined threshold level.