Engine fuel injection control device

Details Engine fuel injection control device Engine fuel injection control device

2000-07-26

2002-05-21

Solis, Erick (Department: 3747)

Internal-combustion engines

Combustion chamber means having fuel injection only

Using multiple injectors or injections

C123S435000, C123S678000, C123S686000

Reexamination Certificate

active

06390058

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel injection control device for a common-rail diesel engine or the like.
2. Description of the Related Art
In common-rail diesel engines, two-stage injection comprising pilot injection and main injection is performed, particularly to prevent white smoke and noise from being emitted between start-up and warm-up.
In conventional practice, the pilot injection quantity is determined in accordance with the PQ map like that shown in
FIG. 7
of the accompanying drawings. In this map, water temperature TW (° C.) is plotted on the horizontal axis, and pilot injection quantity PQ is plotted on the vertical axis. The diagram on the map constantly varies with the operating state of the engine, as will be described below. Solid line (a) designates a given moment in time, but broken line (b) is also possible, depending on the operating state of the engine.
The area inside the map is divided into three regions by two set water temperatures LTW and HTW (LTW<HTW). The regions corresponding to TW≦LTW, TW≧HTW, and LTW<TW<HTW are referred to as a low-temperature area, high-temperature area, and intermediate area, respectively. In the low-temperature area, the pilot injection quantity PQ does not depend on water temperature and remains constant (LLPQ). Similarly, the pilot injection quantity PQ in the high-temperature area does not depend on water temperature and remains constant (HHPQ). It should be noted that LLPQ>HHPQ. The values inside the intermediate area are obtained by the two-point interpolation of LLPQ and HHPQ, and the diagram has a linear shape, as shown in the drawing.
The map is used to calculate the LLPQ and HHPQ values on the basis of the rotational engine speed NE and total injection quantity Q. This is indicated by the use of the smaller subscripts
(NE, Q)
in the drawing. Thus, LLPQ and HHPQ vary with the operating state of the engine, and the diagram on the map constantly varies as a result.
FIG. 8
of the accompanying drawings illustrates a flowchart for calculating the pilot injection quantity. The rotational engine speed NE, total injection quantity Q, and water temperature TW are first sensed or computed in step
401
, and LLPQ and HHPQ are calculated in step
402
. After being thus defined, the PQ map shown in
FIG. 7
is used in the subsequent step
403
to calculate the pilot injection quantity PQ on the basis of the water temperature TW.
An engine commonly emits undesirable white smoke when operating at a low ambient temperature. Methods in which spark advance is employed for the fuel injection timing have been suggested to counter this phenomenon, but these methods increase the noise level. For this reason, pilot injection has become an extremely effective means for keeping white smoke and noise within prescribed limits at low ambient temperatures.
With these conventional techniques, however, the pilot injection quantity is determined without taking into account the ambient temperature in any way. Consequently, these techniques cannot yet be considered adequate for controlling pilot injection, and keeping white smoke and noise within prescribed limits is still a difficult task.
SUMMARY OF THE INVENTION
The present invention provides an engine fuel injection control device for performing prescribed pilot injection and main injection on the basis of the operating state of the engine, comprising pilot injection correction means for correcting the pilot injection quantity on the basis of the ambient temperature.
This arrangement allows the pilot injection quantity to be selected in accordance with the ambient temperature, and pilot injection to be controlled optimally and adequately.
The pilot injection correction means preferably takes corrective action to increase the pilot injection quantity if the ambient temperature falls below a specified level.
The pilot injection correction means preferably operates such that no corrective action is taken if the water temperature is greater a first specified value on a high-temperature side.
The pilot injection correction means preferably operates such that no corrective action is taken if the water temperature is less than a second specified value on a low-temperature side.


REFERENCES:
patent: 5954030 (1999-09-01), Sturman et al.
patent: 6125823 (2000-10-01), Thomas
patent: 6161519 (2000-12-01), Kimura et al.
patent: 0 570 986 (1993-11-01), None
patent: 0 889 220 (1999-01-01), None
patent: 62 000659 (1987-01-01), None
patent: 62000659 (1987-01-01), None
patent: 62 058034 (1987-03-01), None
patent: 01055053 (1989-03-01), None
patent: 02099736 (1990-04-01), None

Affiliated with

Also associated with

Rating

Engine fuel injection control device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Engine fuel injection control device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Engine fuel injection control device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2822584