Fuel property determination apparatus for internal combustion engine

Patent metadata

Field	Value
Publication number	US-9822754-B2
Application number	US-201514813580-A
Country	US
Kind code	B2
Filing date	Jul 30, 2015
Priority date	Jul 31, 2014
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A fuel property determination apparatus for an internal combustion engine is applied to an internal combustion engine that is equipped with an ignition plug and an ignition timing controller. An electronic control unit provided in the fuel property determination apparatus executes a determination process of making a determination on a property of a fuel supplied to the internal combustion engine based on an ignition sufficiency ratio, during a predetermined period after startup of the internal combustion engine. The electronic control unit is configured to determine that the property of the fuel is heavy when a determination index value that is obtained by subjecting the ignition sufficiency ratio to a smoothing process is equal to or larger than a predetermined threshold. The electronic control unit is configured to set a smoothing coefficient to a value corresponding to each of a first period, a second period, and a third period.

First claim

What is claimed is:

1. A fuel property determination apparatus for an internal combustion engine including an ignition plug having a spark generation portion, the fuel property determination apparatus comprising:
an electronic control unit programmed to:
(i) correct an ignition timing as a timing for generating a spark from the spark generation portion,
(ii) execute feedback control of an engine rotational speed such that an engine rotational speed converges to a target rotational speed,
(iii) calculate an ignition sufficiency ratio during a preset period after startup of the internal combustion engine, and execute a determination process of making a determination on a property of a fuel supplied to the internal combustion engine based on the ignition sufficiency ratio, the ignition sufficiency ratio being a ratio of an advancement correction amount of the ignition timing to a maximum ignition correction width as a maximum width that allows the ignition timing to be corrected when the ignition timing is corrected in the feedback control,
(iv) determine that the property of the fuel is heavy when a determination index value obtained by subjecting the ignition sufficiency ratio to a smoothing process is equal to or larger than a predetermined threshold, the smoothing process being a process of calculating a weighted average of an ignition sufficiency ratio obtained this time and a determination index value obtained last time, and
(v) set a smoothing coefficient to a value corresponding to each of a first period, a second period, and a third period, the smoothing coefficient being an inverse of a coefficient corresponding to a weight of the ignition sufficiency ratio obtained this time in the smoothing process, the first period being a period from startup of the internal combustion engine to attainment of the target rotational speed by the engine rotational speed, the second period being a period from attainment of the target rotational speed by the engine rotational speed to lapse of a predetermined period, and the third period being a period after lapse of the predetermined period from attainment of the target rotational speed by the engine rotational speed.

2. The fuel property determination apparatus according to claim 1 , wherein
a first smoothing coefficient is larger than a third smoothing coefficient,
the third smoothing coefficient is larger than or equal to a second smoothing coefficient,
the first smoothing coefficient is a smoothing coefficient in the first period,
the second smoothing coefficient is a smoothing coefficient in the second period, and
the third smoothing coefficient is a smoothing coefficient in the third period.

3. The fuel property determination apparatus according to claim 1 , wherein the electronic control unit is further programmed to determine that the property of the fuel is heavy when the engine rotational speed has not reached the target rotational speed even after lapse of a predetermined period from startup of the internal combustion engine.

4. The fuel property determination apparatus according to claim 2 , further comprising:
a coolant temperature sensor configured to detect a temperature of a coolant in the internal combustion engine,
wherein the electronic control unit is further programmed to set the third smoothing coefficient to 1 when the temperature of the coolant detected by the coolant temperature sensor at a time of startup of the internal combustion engine is equal to or higher than a predetermined threshold.

5. The fuel property determination apparatus according to claim 1 , further comprising:
a fuel feed detector configured to detect an operation of feeding fuel,
wherein the electronic control unit is further programmed to, when the fuel feed detector detects the operation of feeding fuel, (i) nullify a result of determination obtained by the determination process, and (ii) prohibit the determination process from being executed when the electronic control unit has determined that the property of the fuel supplied to the internal combustion engine is heavy.

Assignees

• Toyota Motor Co Ltd

Inventors

• Yamashita Akitaka
• Watanabe Mikio

Classifications

• F02D41/0025 Primary

  Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures · CPC title

• F02P15/006 Primary

  Ignition installations combined with other systems, e.g. fuel injection (to advance or to retard the ignition spark F02P5/045) · CPC title

• F02P5/1506

  with particular means during starting · CPC title

• F02P9/002

  Control of spark intensity, intensifying, lengthening, suppression (by means of current control in the storage devices F02P3/05, F02P3/09, during starting F02P15/12) · CPC title

• G01N33/225 Primary

  Gaseous fuels, e.g. natural gas · CPC title