Crankcase ventilation pressure management for turbocharged engine

Patent metadata

Field	Value
Publication number	US-9909470-B2
Application number	US-201514694118-A
Country	US
Kind code	B2
Filing date	Apr 23, 2015
Priority date	Apr 23, 2015
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A crankcase ventilation system for a turbocharged engine has full bi-directional flow for an idle state and a boosted state. A PCV valve provides air flow from the crankcase to the intake manifold in the idle state. A restriction in a first vent line limits fresh air into the crankcase in the idle state. A PCV bypass permits a one-way flow into the crankcase via a second vent line bypassing the PCV valve in the boosted state. A pressure relief valve in communication with the first vent line is configured to bypass the restriction in the boosted state when a pressure in the crankcase exceeds a threshold pressure. In a preferred embodiment, the PCV bypass is configured to bypass both the PCV valve and a pull separator (i.e., oil separator at the second vent line) in the boosted state.

First claim

What is claimed is:

1. A vehicle comprising:
an internal combustion engine with an intake manifold receiving fresh air via an inlet duct, wherein the engine includes a crankcase;
a turbocharger having a compressor with an inlet coupled to the inlet duct and an outlet coupled to the intake manifold, the engine and turbocharger having an idle state and a boosted state;
a first vent line communicating between the crankcase and the inlet duct; and
a second vent line communicating between the crankcase and the intake manifold;
a PCV valve in communication with the second vent line responsive to a vacuum pressure in the intake manifold to allow air flow from the crankcase to the intake manifold in the idle state;
a restriction in communication with the first vent line configured to limit a flow of fresh air via the first vent line into the crankcase in the idle state;
a PCV bypass configured to permit a one-way flow into the crankcase via the second vent line bypassing the PCV valve in the boosted state; and
a pressure relief valve in communication with the first vent line configured to bypass the restriction in the boosted state when a pressure in the crankcase exceeds a threshold pressure.

2. The vehicle of claim 1 further comprising:
a pull separator in communication with the second vent line; and
a push separator in communication with the first vent line;
wherein the PCV bypass is configured to bypass both the PCV valve and the pull separator in the boosted state.

3. The vehicle of claim 1 wherein the PCV bypass is comprised of a check valve.

4. A ventilation system for a crankcase of a combustion engine with a turbocharger, comprising:
a PCV valve and a fresh air restriction cooperating to clear crankcase gases and maintain a crankcase vacuum in an idle state; and
a PCV bypass and a relief valve cooperating to clear crankcase gases and limit a positive crankcase pressure in a boosted state.

5. The ventilation system of claim 4 further comprising:
a first vent line coupling the restriction and the relief valve to a fresh air inlet of the turbocharger; and
a second vent line coupling the PCV valve and the PCV bypass to an intake manifold of the engine.

6. The ventilation system of claim 5 further comprising:
a pull separator in communication with the second vent line; and
a push separator in communication with the first vent line;
wherein the PCV bypass is configured to bypass both the PCV valve and the pull separator.

7. The ventilation system of claim 4 wherein the PCV bypass is comprised of a check valve.

Assignees

• Ford Global Tech Llc

Inventors

• Christian Adam M
• Newman Christopher W
• Randall Katherine Jane

Classifications

• F01M2013/027

  with a turbo charger or compressor · CPC title

• F02B37/00

  Engines characterised by provision of pumps driven at least for part of the time by exhaust · CPC title

• F01M13/022

  using engine inlet suction · CPC title

• F01M13/028

  of positive pressure · CPC title

• F01M13/04 Primary

  having means for purifying air before leaving crankcase, e.g. removing oil · CPC title