Control system for turbo-compound system

Patent metadata

Field	Value
Publication number	US-10047666-B2
Application number	US-201415024642-A
Country	US
Kind code	B2
Filing date	Nov 7, 2014
Priority date	Dec 4, 2013
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

An object is to enable low fuel-consumption operation of an engine by controlling a back pressure and a power generation amount taking account of a trade-off relationship between deterioration of fuel efficiency due to an increase in pumping loss due to a back-pressure rise of the engine and improvement of fuel efficiency due to recovery of exhaust energy by a turbo compound.

First claim

The invention claimed is:

1. A control system for a turbo-compound system, comprising:
an exhaust turbocharger including an exhaust turbine driven by exhaust gas from an engine and a compressor
compressing intake air and supplying the compressed air to the engine;
a turbine generator including a power generation turbine driven by the exhaust gas from the engine and a generator connected to the power generation turbine;
a storage unit storing electric power generated by the turbine generator;
an engine controller configured to control operation of the engine;
wherein the engine controller is configured to determine a target boost pressure based on an engine rotation speed and engine load of the engine and to include a power-generation-mode determination unit which determines a command power generation mode, based on the target boost pressure and remaining charge of the storage unit, to one of:
a maximum regeneration mode to cause the turbine generator to perform regeneration operation at a maximum capacity without limiting power generation of the turbine generator;
a no-regeneration mode to stop power generation of the turbine generator; and
a low fuel-consumption mode;
a turbo controller configured to receive the target boost pressure and the command power generation mode from the engine controller at a predetermined communication cycle;
wherein the turbo controller includes a control computation part and a sensor-signal input part;
wherein the control computation part includes:
a boost-pressure control unit which controls a boost pressure of the exhaust turbocharger based on the command of the target boost pressure from the engine controller;
a power-generation-mode setting unit which sets a power generation mode based on the command of the power generation mode from the engine controller;
a power-generation-amount control unit which controls a power generation amount of the turbine generator in accordance with the setting mode of the power-generation mode setting unit; and
a back-pressure control unit configured to control at least one of a bypass control valve bypassing the exhaust gas being introduced into the exhaust turbine and a variable nozzle mechanism restricting the exhaust gas being introduced into the exhaust turbine; and
wherein the sensor-signal input part is configured to read in a sensor signal from a back-pressure sensor for detecting a pressure of the exhaust gas flowing into the exhaust turbine; and
wherein the turbo controller is configured to control the power generation-amount control unit and the back-pressure control unit to achieve at least a recovery amount of exhaust energy recovered by the turbine generator is greater than an increase in a fuel consumption due to an increase in pumping loss due to a back-pressure rise caused in response to rotation of the turbine generator, during the low-fuel-consumption mode.

2. The control system for a turbo-compound system according to claim 1 ,
wherein the turbo controller has a back-pressure/power-generation-amount map in which a relationship between the back pressure and the power generation amount of the turbine generator is set in advance, the power generation amount being such that low fuel-consumption is sustainable with respect to the back pressure, and is configured to control the power-generation-amount control unit and the back-pressure control unit based on the back-pressure/power-generation-amount map.

3. The control system for a turbo-compound system according to claim 1 ,
wherein the back-pressure control unit is configured to control the bypass control valve, and
wherein the power-generation-amount control unit is configured to control a converter connected to the turbine generator.

4. The control system for a turbo-compound system according to claim 3 , further comprising:
an electric compressor disposed on a downstream side, with respect to a flow of air supply, of a compressor of the exhaust turbocharger.

5. The control system for a turbo-compound system according to claim 1 ,
wherein the back-pressure control unit is configured to control a variable nozzle mechanism to restrict the exhaust gas being supplied into turbine blades of the exhaust turbine, and
wherein the power-generation-amount control unit is configured to control a converter connected to the turbine generator.

6. The control system for a turbo-compound system according to claim 1 ,
wherein the turbo turbo-compound system further comprises an electric compressor,
wherein the back-pressure control unit further comprises an additional bypass control valve for bypassing the exhaust gas being supplied to a power generation turbine of the turbine generator rotated by the exhaust gas from the engine, and
wherein the power-generation-amount control unit further comprises a converter connected to the turbine generator.

7. The control system for a turbo-compound system according to claim 1 ,
wherein the turbo controller is configured to, during the low fuel-consumption mode, control the boost pressure of the exhaust turbocharger to achieve the target boost pressure by the boost pressure control unit and to control the power generation-amount control unit and the back-pressure control unit based on the pressure of exhaust gas flowing into the exhaust turbine when the target boost pressure is achieved.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Yamashita Yukio
• Takayanagi Ko
• Sase Ryo
• Matsuo Atsushi
• Hayashi Rikikazu

Classifications

• F02D2041/1418

  Several control loops, either as alternatives or simultaneous · CPC title

• F02B2039/168

  the rotational speed of pump or exhaust drive being limited · CPC title

• F02D2041/1409

  using at least a proportional, integral or derivative controller · CPC title

• F01N5/04

  the devices using kinetic energy · CPC title

• F02D2200/503

  Battery correction, i.e. corrections as a function of the state of the battery, its output or its type · CPC title