Engine control apparatus to predict engine speed accurately

Patent metadata

Field	Value
Publication number	US-2016305355-A1
Application number	US-201615097606-A
Country	US
Kind code	A1
Filing date	Apr 13, 2016
Priority date	Apr 17, 2015
Publication date	Oct 20, 2016
Grant date	—

Abstract

An engine control apparatus predicts the speed of an engine in a normal rotation range as a function of a loss energy in an engine rotation pulsating period and also predicts the speed of the engine in a reverse rotation range as a function of a pumping loss component and a loss energy which is derived by reversing the sign of a value of a friction component that is a portion of the loss energy in the normal rotation range and arises from mechanical friction to which the piston is subjected during stroke thereof. The pumping loss component is an energy loss occurring in the intake stroke of the engine. This calculation enhances the accuracy in predicting a future engine speed between start of a drop in speed of the engine resulting from stop of combustion of fuel and stop of rotation of the engine.

First claim

What is claimed is:

1 . An engine control apparatus which works to predict a speed of an engine in a period of time between start of a drop in speed of the engine resulting from stop of combustion of fuel in the engine and stop of rotation of the engine, comprising:
a first calculator which predicts a future speed of the engine in a normal rotation range thereof as a function of a loss energy in a latest one of engine rotation pulsating periods each of which corresponds to a cycle of a change in speed of the engine arising from increasing and decreasing of volume of a cylinder of the engine; an energy calculator which reverses a positive or negative sign of a value of a friction component that is a portion of the loss energy in the normal rotation range and which arises from mechanical friction to which a piston of the engine is subjected during stroke thereof and calculates a loss energy in a reverse rotation range of the engine as a function of the value of the friction component whose sign has been reversed and a pumping loss component that is an energy loss occurring in an intake stroke of the engine; and a second calculator which predicts a future speed of the engine in the reverse rotation range of the engine based on the loss energy derived by said energy calculator.

2 . An engine control apparatus as set forth in claim 1 , wherein further comprising a pressure determiner which determines a pressure in the cylinder of the engine in which the piston is undergoing the intake stroke, and wherein the energy calculator determines the pumping loss component as a function of the pressure in the cylinder, as derived by the pressure determiner.

3 . An engine control apparatus as set forth in claim 1 , wherein the engine is a multi-cylinder engine, and wherein said energy calculator determines the pumping loss component as a function of a loss energy at an angular position of rotation of the engine where a volume of one of cylinders of the engine in which a piston is undergoing a compression stroke is equal to that of one of the cylinders in which a piston is undergoing an expansion stroke.

4 . An engine control apparatus as set forth in claim 1 , further comprising an automatic engine stop and restart function which automatically stops the engine when a given automatic engine stop condition is met and rotates an output shaft of the engine through a starter device to restart the engine when a given engine restart condition is met after the engine is stopped automatically, and also comprising a starter controller which controls a time when a pinion of the starter device is to be moved toward the engine based on the speed of the engine, as predicted by the first calculator or the second calculator.

Assignees

• Denso Corp

Inventors

• Takizawa Tomohiro
• Kawazu Shinsuke

Classifications

• F02D41/0097 Primary

  using means for generating speed signals · CPC title

• F02N11/0818

  Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode · CPC title

• F02D2250/06

  Reverse rotation of engine · CPC title

• F02D2200/101

  Engine speed · CPC title

• F02N19/005

  Aiding engine start by starting from a predetermined position, e.g. pre-positioning or reverse rotation · CPC title