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Implementing DSF with fast single solenoid using GDi injector driver

IP.com Disclosure Number: IPCOM000238953D
Publication Date: 2014-Sep-26
Document File: 15 page(s) / 3M

Publishing Venue

The IP.com Prior Art Database

Related People

John Nightingale: CONTACT

Abstract

Use a single OCV (oil control valve) solenoid to activate and deactivate the intake and exhaust valves of an engine operating in a dynamic skip fire mode. In engines have direct fuel injection the same circuitry used to drive a fuel injector may be used to drive the OCV solenoid, since a skipped cylinder does not require fuel injection and thus activation of the OCV solenoid and fuel injector never overlap. The same circuitry may also to used to verify motion of both the fuel injector and OCV solenoid armature.

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Implementing DSF with fast single solenoid using GDi injector driver

Mark A. Shost, John W. Parsels, Matthew Younkins

Tula Technology Inc., 240 Zanker Rd., San Jose, CA 95131

Abstract

Use a single OCV (oil control valve) solenoid to activate and deactivate the intake and exhaust valves of an engine operating in a dynamic skip fire mode. In engines have direct fuel injection the same circuitry used to drive a fuel injector may be used to drive the OCV solenoid, since a skipped cylinder does not require fuel injection and thus activation of the OCV solenoid and fuel injector never overlap. The same circuitry may also to used to verify motion of both the fuel injector and OCV solenoid armature.

Problem(s) solved

To minimize cost of DSF application the existing driver circuit for the fuel injector could be used to drive the deactivation solenoids.  Current solenoids in use for CDA (Cylinder Deactivation) and the overall switching times are significantly slower (>0.020 seconds) than the requirements of DSF engine operation.  In order to meet the DSF requirements (<0.010 seconds) a boosted voltage would improve OCV energize time (energizing OCV usually deactivates the engine valves) as well as provide for better repeatability across anticipated battery voltage range.  Use of a peak and hold circuit, that holds the magnetic flux at a lower level than peak voltage would improve OCV de-energize times , to re-activate the engine valve, as well as improve repeatability.  Further improvement to de-energize times can be achieved by applying a reverse voltage to collapse the field more quickly.  This requires 16 valves and drive circuits as currently implemented in the Tula demo vehicle.  Adoption of a single fast OCV solenoid reduces the requirement to 8 valves and circuits.  Ability to reconfigure the existing boost circuit to direct use to the injector for FIRE events and to the OCV for SKIP events can eliminate the need for additional hardware. 

Limitations of current techniques

Adapting to the requirements of DSF operation would traditionally be done thru addition of 16 or 8 additional drivers to support the OCVs.  This adds package space and cost to the application.

Summary of the invention

Implementation of Dynamic Skip Fire (DSF) is based on cylinder deactivation.  Cylinder deactivation is achieved by deactivating the intake and exhaust valves of the engine as shown in Figure 1.  In some current production applications the deactivation mechanism is a collapsible lifter which a control port of the lifter is connected to an Oil Control Valve (OCV) to permit engine valve de-activation upon command from the Engine Control Module (ECM).  In conventional 2-mode cylinder deactivation as shown in Figure 2 the firing pattern is static (fixed) for subsequent engine cycles when operating in deactivation mode.  In DSF operation the commanded cylinder number deactivating generally changes by engine cycle producing a dynamic (rotating) engine firing...