Control system for internal combustion engine

• US 7,673,618 B2
• Filed: 09/11/2007
• Issued: 03/09/2010
• Est. Priority Date: 09/11/2006
• Status: Expired due to Fees

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Yamaguchi, Satoshi, Hasegawa, Mamoru, Yamanaka, Tatsuo, Sakamoto, Hideki, Kitayama, Naoto
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US11/898,275
• Publication Number:
  US 20080262699A1
• Time in Patent Office: 910 Days
• Field of Search: 123/435, 123/568.12, 123/406.3, 123/406.41, 701/108, 73/350.2
• US Class Current: 123/435
• CPC Class Codes: F02D 19/061 by controlling fuel injectors
• CPC Class Codes: F02D 19/0636 by estimation, i.e. without using direct measurements of a corresponding sensor
• CPC Class Codes: F02D 19/0649 Liquid fuels having different boiling temperatures, volatilities, densities, viscosities, cetane or octane numbers
• CPC Class Codes: F02D 2200/0612 determined by estimation
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 41/0025 Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• CPC Class Codes: F02D 41/0055 Special engine operating conditions, e.g. for regeneration of exhaust gas treatment apparatus
• CPC Class Codes: F02D 41/2416 Interpolation techniques
• CPC Class Codes: F02D 41/403 with pilot injections
• CPC Class Codes: F02M 26/06 Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor
• CPC Class Codes: F02M 26/07 Mixed pressure loops, i.e. wherein recirculated exhaust gas is either taken out upstream of the turbine and reintroduced upstream of the compressor, or is taken out downstream of the turbine and reintroduced downstream of the compressor
• CPC Class Codes: F02M 26/15 in relation to engine exhaust purifying apparatus
• CPC Class Codes: F02M 26/35 with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters
• CPC Class Codes: F02M 26/48 EGR valve position sensors details of the sensor installation in the valve housing F02M26/72
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A control system for an internal combustion engine, which is capable of estimating a property of fuel accurately even when the engine is in an operating condition other than idling. An in-cylinder pressure sensor detects an amount of change in pressure in a cylinder #1 of the engine as a pressure change amount. An ECU calculates an amount of heat released in the cylinder #1 as a heat release amount, according to the pressure change amount. A vehicle speed sensor, a crank angle sensor, and an accelerator pedal opening sensor detect load on the engine. The ECU estimates a cetane number of fuel based on the calculated heat release amount and the detected load on the engine.

Claims

1. A control system for an internal combustion engine, comprising:

pressure change amount-detecting means for detecting an amount of change in pressure within a cylinder of the engine as a pressure change amount;

heat release amount-calculating means for calculating an amount of heat released in the cylinder as a heat release amount, according to the detected pressure change amount;

load detecting means for detecting load on the engine; and

fuel property-estimating means for estimating a property of fuel, based on the calculated heat release amount and the detected load on the engine.

2. A control system as claimed in claim 1, further comprising:

exhaust gas-recirculating means for recirculating part of exhaust gases exhausted from the cylinder to the cylinder; and

exhaust gas recirculation amount-reducing means for reducing an amount of exhaust gases recirculated to the cylinder, according to the load on the engine, when said fuel property-estimating means estimates the property of fuel.

3. A control system as claimed in claim 1, further comprising heat release amount-storing means for storing amounts of heat released by combustion of fuels having respective predetermined properties different from each other, on a predetermined property-by-predetermined property basis, according to the load on the engine, as reference heat release amounts, in advance, and

wherein said fuel property-estimating means estimates the property of fuel based on the reference heat release amounts associated with the respective predetermined properties retrieved from said heat release amount-storing means according to the detected load on the engine, and the heat release amount calculated by said heat release amount-calculating means.

4. A control system as claimed in claim 3, wherein said fuel property-estimating means has provisional determination means for provisionally determining the property of fuel according to the retrieved reference heat release amounts associated with the respective predetermined properties and the calculated heat release amount, and estimates the property of fuel by subjecting the provisionally determined property of fuel to a filtering process.

5. A control system as claimed in claim 3, wherein said fuel property-estimating means subjects the detected load on the engine to a filtering process, and retrieves the reference heat release amounts according to the load on the engine subjected to the filtering process.

6. A control system as claimed in claim 5, wherein said load detecting means detects a plurality of kinds of loads different from each other, and

wherein said fuel property-estimating means subjects the detected different kinds of loads to respective filtering processes having the same filter characteristic.

7. A control system for an internal combustion engine, comprising:

pressure change amount-detecting means for detecting an amount of change in pressure within a cylinder of the engine as a pressure change amount;

heat release amount-calculating means for calculating an amount of heat released in the cylinder as a heat release amount, according to the detected pressure change amount;

load detecting means for detecting load on the engine; and

cetane number-estimating means for estimating a cetane number of fuel, based on the calculated heat release amount and the detected load on the engine.

8. A control system for an internal combustion engine that sequentially performs a pilot injection and a main injection to thereby inject fuel into a cylinder, comprising:

pressure change amount-detecting means for detecting an amount of change in pressure within a cylinder of the engine caused by combustion of fuel injected by the pilot injection, as a pressure change amount;

heat release amount-calculating means for calculating an amount of heat released in the cylinder as a heat release amount, according to the detected pressure change amount;

load detecting means for detecting load on the engine; and

fuel property-estimating means for estimating a property of fuel, based on the calculated heat release amount and the detected load on the engine.