Controller

Patent metadata

Field	Value
Publication number	US-9784196-B2
Application number	US-201514885241-A
Country	US
Kind code	B2
Filing date	Oct 16, 2015
Priority date	Oct 31, 2014
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

A controller calculates a specific humidity of an intake air based on a relative humidity of the intake air, an intake air temperature, and an intake air pressure. Then the controller calculates a water vapor amount in the intake air based on the specific humidity and a mass flow rate of the intake air obtained from an air intake rate. By calculating the water vapor amount in the intake air based on information that directly represents the status of the intake air, this water vapor amount may be calculated more accurately. As a result, a generation amount of condensed water may be estimated more accurately. Therefore, accumulation of condensed water may be suppressed while recirculating as much of a low pressure exhaust gas as possible, and thus fuel economy may be sufficiently improved.

First claim

The invention claimed is:

1. A controller for controlling an internal combustion engine which includes a supercharger, a low pressure exhaust gas recirculation (EGR) device, an air intake rate detector, an intake air temperature detector, and a relative humidity detector, where (i) the low pressure EGR device recirculates exhaust gas from an exhaust passage downstream of a resistive element to an intake passage upstream of a compressor of the supercharger, (ii) the resistive element resists the exhaust gas, (iii) the air intake rate detector detects an air intake rate, (iv) the intake air temperature detector detects an intake air temperature, and (v) the relative humidity detector detects a relative humidity of an intake air, the controller comprising:
a specific humidity calculation unit that calculates a specific humidity of the intake air based on the relative humidity, the intake air temperature, and an intake air pressure of the intake air; and
a first vapor amount calculation unit that calculates a water vapor amount in the intake air based on a mass flow rate of the intake air and the specific humidity, the mass flow rate being obtained from the air intake rate;
a second vapor amount calculation unit;
a generation amount estimation unit; and
a recirculation controller, wherein
the internal combustion engine includes an EGR cooler and an intercooler, the EGR cooler cooling the exhaust gas recirculated by the low pressure EGR device, the intercooler cooling supercharged air which is heated due to compression by the compressor,
the second vapor amount calculation unit calculates a water vapor amount in a combustion chamber of the internal combustion engine generated due to combustion in a the combustion chamber,
the generation amount estimation unit estimates a generation amount of condensed water in the internal combustion engine based on the water vapor amount in the intake air, the water vapor amount generated due to combustion, and a cooling condition of the EGR cooler and the intercooler, the cooling condition indicating an operating condition for the EGR cooler and the intercooler, and
the recirculation controller controls a recirculation amount of a low pressure exhaust gas based on the generation amount or based on an accumulation amount of the condensed water obtained from the generation amount, the recirculation amount of the low pressure exhaust gas being an amount of the exhaust gas recirculated by the low pressure EGR device.

2. A system, comprising:
an internal combustion engine which includes
a supercharger,
a low pressure exhaust gas recirculation (EGR) device,
an air intake rate detector,
an intake air temperature detector, and
a relative humidity detector, where
(i) the low pressure EGR device recirculates exhaust gas from an exhaust passage downstream of a resistive element to an intake passage upstream of a compressor of the supercharger,
(ii) the resistive element resists the exhaust gas, (iii) the air intake rate detector detects an air intake rate,
(iv) the intake air temperature detector detects an intake air temperature, and
(v) the relative humidity detector detects a relative humidity of an intake air; and

a controller which includes
a specific humidity calculation unit that calculates a specific humidity of the intake air based on the relative humidity, the intake air temperature, and an intake air pressure of the intake air;
a first vapor amount calculation unit that calculates a water vapor amount in the intake air based on a mass flow rate of the intake air and the specific humidity, the mass flow rate being obtained from the air intake rate;
a second vapor amount calculation unit;
a generation amount estimation unit; and
a recirculation controller, wherein

the internal combustion engine cooler includes an EGR cooler and an intercooler, the EGR cooler cooling the exhaust gas recirculated by the low pressure EGR device, the intercooler cooling supercharged air which is heated due to compression by the compressor,
the second vapor amount calculation unit calculates a water vapor amount in a combustion chamber of the internal combustion engine generated due to combustion in the combustion chamber,
the generation amount estimation unit estimates a generation amount of condensed water in the internal combustion engine based on the water vapor amount in the intake air, the water vapor amount generated due to combustion, and a cooling condition of the EGR cooler and the intercooler, the cooling condition indicating an operating condition for the EGR cooler and the intercooler, and
the recirculation controller controls a recirculation amount of a low pressure exhaust gas based on the generation amount or based on an accumulation amount of the condensed water obtained from the generation amount, the recirculation amount of the low pressure exhaust gas being an amount of the exhaust gas recirculated by the low pressure EGR device.

3. The system of claim 2 , wherein
the controller further includes an intake air pressure estimation unit, and
the intake air pressure estimation unit
obtains an atmospheric pressure from an atmospheric pressure sensor included in the internal combustion engine,
estimates a pressure loss at an air cleaner based on the mass flow rate of the intake air obtained from the air intake rate, the air cleaner being disposed in the intake passage of the internal combustion engine and upstream of the compressor of the supercharger, the pressure loss being estimated as a pressure difference across the air cleaner, and
estimates the intake air pressure based on the atmospheric pressure and the pressure loss.

Assignees

• Denso Corp

Inventors

• Ban Takao

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02M26/47

  the characteristics being temperatures, pressures or flow rates · CPC title

• F02B29/0406

  Layout of the intake air cooling or coolant circuit · CPC title

• F02M26/23

  Layout, e.g. schematics · CPC title

• F02M35/10222

  Exhaust gas recirculation [EGR]; Positive crankcase ventilation [PCV]; Additional air admission, lubricant or fuel vapour admission · CPC title