Compressor pre-spin control method

Patent metadata

Field	Value
Publication number	US-9441559-B2
Application number	US-201414535670-A
Country	US
Kind code	B2
Filing date	Nov 7, 2014
Priority date	Nov 8, 2013
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A method is provided for controlling a pre-spin operation of a compressor of an internal combustion engine provided with a turbocharger. The presence of a turbocharger imposes additional requirements on the method. The wear of a compressor clutch is proportional to the transferred energy when the clutch is engaged. In order to reduce the wear of the compressor clutch, or increase the maximum engine speed where it is allowed to engage the compressor, a compressor pre-spin operation is used to reduce the transferred energy when the clutch is engaged. The pre-spin is achieved by controlling the air mass flow over the compressor by controlling a bypass throttle angle of a bypass throttle. The bypass throttle is provided in a parallel conduit to the compressor, bypassing the compressor. Since the air mass flow over the compressor affects the air mass flow to the turbocharger, the method takes the turbocharger into consideration.

First claim

What is claimed is:

1. A method for controlling a pre-spin operation of a compressor of an internal combustion engine, wherein the internal combustion engine comprises an air intake, a compressor conduit, a bypass conduit and a turbocharger, wherein the air intake is in fluid communication with an air inlet of the turbocharger, the compressor conduit comprises a compressor and is arranged between the air intake and the turbocharger such that the compressor is in fluid communication with the air intake and the turbocharger, and the bypass conduit comprises a bypass throttle and is arranged in fluid communication with the air intake and the turbocharger inlet such that the bypass conduit bypasses the compressor, wherein a compressor clutch connects the compressor to a crankshaft of the internal combustion engine such that the compressor can be engaged and disengaged from the crankshaft, and wherein the bypass throttle can be controlled by setting a bypass throttle angle such that the bypass throttle can be controlled between an open position and a closed position, the method comprising:
checking a number of conditions including:
if the compressor clutch is in a disengaged state,
if a load of the internal combustion engine is in a predetermined load range,
if an air mass flow delivered by the turbocharger is within a predetermined mass flow range,
if a speed of the compressor is below a threshold value, and
if the bypass throttle is at least partially open; and

if the conditions are fulfilled, performing the following:
calculating a bypass throttle angle dependent on at least a mass flow over the internal combustion engine and a target pressure difference over the compressor such that a predetermined pre-spin of the compressor is achieved, the internal combustion engine load stays in the predetermined load range, and the air mass flow delivered by the turbocharger stays within the predetermined mass flow range; and
setting the bypass throttle angle according to the calculated bypass throttle angle.

2. The method according to claim 1 wherein the internal combustion engine is connected to a transmission, and wherein the method comprises an additional condition of checking if one of a number of predefined gears of the transmission is engaged.

3. The method according to claim 2 wherein the internal combustion engine additionally comprises a temperature sensor provided downstream of the air intake and upstream of a splitting point of the compressor conduit and the bypass conduit for measuring compressor inlet temperature, wherein the method further comprises measuring a compressor inlet temperature, and wherein the calculating of the bypass throttle angle is additionally dependent on the measured temperature.

4. The method according to claim 3 wherein the calculating of the bypass throttle angle is dependent on a mass flow over the bypass throttle.

5. The method according to claim 2 wherein the calculating of the bypass throttle angle is dependent on a mass flow over the bypass throttle.

6. A vehicle comprising an internal combustion engine controlled according to the method of claim 2 .

7. The method according to claim 1 wherein the internal combustion engine additionally comprises a temperature sensor provided downstream of the air intake and upstream of a splitting point of the compressor conduit and the bypass conduit for measuring compressor inlet temperature, wherein the method further comprises measuring a compressor inlet temperature, and wherein the calculating of the bypass throttle angle is additionally dependent on the measured temperature.

8. The method according to claim 7 wherein the calculating of the bypass throttle angle is dependent on a mass flow over the bypass throttle.

9. The method according to claim 8 wherein the calculating of the bypass throttle angle is performed based on the following throttle position equation:
BT−α= f (({dot over ( m )} engine( t )− {dot over (m)} comp target( t ))*√{square root over ( RTus )}/( Cd*Pus )* f ( P ratio)),

wherein BT−α is the bypass throttle angle, {dot over (m)} engine(t) is mass flow over the engine at time t, {dot over (m)} comp target(t) is requested mass flow over the compressor at time t, R is the gas constant, approximately 287 J/KgK, Tus is the temperature measured by the temperature sensor upstream of the compressor, Cd is discharge coefficient for the bypass throttle, Pus is requested pressure downstream of a merging point of the compressor conduit and the bypass conduit, and Pratio is target pressure difference over the compressor.

10. The method according to claim 9 wherein the method additionally comprises using a feedback functionality such that the mass flow over the bypass throttle continuously can be updated, wherein the feedback functionality comprises:
calculating a feedback mass flow over the throttle ({dot over (m)} feedback bypass(t)),
adding the calculated feedback mass flow over the throttle ({dot over (m)} feedback bypass(t)) to the current mass flow over the throttle ({dot over (m)} bypass(t)) such that a corrected mass flow over the throttle {dot over (m)} bypass(t+1)) is calculated according to:
{dot over ( m )} bypass( t+ 1)={dot over ( m )} bypass( t )+{dot over ( m )} feedback bypass( t ).

11. The method according to claim 10 wherein the internal combustion engine additionally comprises a turbocharger inlet pressure sensor provided downstream of the merging point where the compressor conduit and the bypass conduit merge and upstream of the turbocharger for measuring a turbocharger inlet pressure, and wherein the method further comprises:
measuring the turbocharger inlet pressure (y(t)),
calculating the feedback mass flow over the throttle ({dot over (m)} feedback bypass(t)) by using the following feedback equation:

m
.

⁢

⁢
feedback
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bypass
⁡

(
t
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=

Kp
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(

r
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(
t
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y
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(
t
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+

∫
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t

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Ki
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r

Assignees

• Volvo Car Corp

Inventors

• Svensson Johan
• Carlen Mattias

Classifications

• F02D2009/0279

  Throttle valve control for intake system with two parallel air flow paths, each controlled by a throttle, e.g. a resilient flap disposed on a throttle · CPC title

• F02D41/0007 Primary

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• F02D2009/0283

  Throttle in the form of an expander · CPC title

• F02B37/16

  by bypassing charging air · CPC title

• F02D2200/0406

  Intake manifold pressure · CPC title