Transcript
VVEL Technology Briefing Variable Valve Event & Lift System July 13, 2007
Junichi Yajima Chief Powertrain Engineer Powertrain Engineering Division Nissan Motor Co., Ltd.
Agenda 1. 2. 3. 4.
The Powertrain Concept Benefits of VVEL VVEL Structure VQ37VHR
1. The Powertrain Concept
1-1. Core Values of Nissan Technology Trusted Driving Pleasure
Trust: ὉEnvironment
ὉSafety
Environment
Driving Pleasure:
ὉDynamic Performance ὉLife on Board Safety Environment
Q u a li t y, Cos t
Dynamic Dynamic Performance Performance
1-2. Powertrain Engineering Concept ṲNissan's powertrain development aims to develop an ultimate powertrain which balances 3 factors [Emotion, Efficiency, Emission] at a high level
Emotion Performance
Ultimate Powertrain Efficiency CO2 reduction
Emission
1-3. VVEL Concept ṲVVEL highly-balances 3 factors [Emotion, Efficiency, Emission]
Emotion Emotion
VVEL Efficiency Efficiency
Emission Emission
2. Benefits of VVEL ¾What is VVEL? ¾Benefits of VVEL
2-1-1. What is VVEL? ṲConventional engines have one-type cam lobes, limiting it to one pattern of movement ṲVVEL combined with C-VTC enables continuous valve movement
Conventional Engine
VVEL-equipped Engine
VVEL
2-1-2. What is VVEL? ṲVVEL controls intake amount through intake-valves of the combustion chamber, where conventional engines used throttle valves VVEL-equipped Engine
Conventional Engine
Throttle Throttle
open
open/close
Variable intake valve lift
Constant intake valve lift The fixed cam which moves the valve, enables intake-air control at throttle valve opening
Direct intake-air control with continuously variable valve lift
2. Benefits of VVEL ¾What is VVEL? ¾Benefits of VVEL
2-2-1. Benefits of VVEL – Fuel Efficiency (When throttle opening is small) ṲIn driving condition on a flat road at constantly 40km/h (when accelerator is pressed halfway or less) there is little pumping loss with VVEL-equipped engines
Conventional Engine
VVEL-equipped Engine Throttle Valve
Throttle Valve Close
Open Choking
Atmosphere Pressure
Negative Pressure
Big negative work (pumping loss)
Similar condition to the large amount of strength needed to pull a thin syringe needle. (large pumping loss)
Valve Throttle (=non throttle) little negative work
Similar to good condition where little strength is needed to pull thick syringe needle. (little pumping loss)
2-2-2. Benefits of VVEL – Fuel Efficiency (When throttle opening is small)
Cam shaft Friction
ṲIn driving ranges of small throttle opening, intake-valve lift can be kept low to reduce camshaft friction compared to conventional engine
VVEL-equipped Engine Conventional Engine (small lift amount) (fixed valve lift)
2-2-3. Benefits of VVEL – Better Response ṲVVEL-equipped engines control air amount at intake-valve by the combustion chamber entrance, which enables necessary air to be sent promptly to combustion chamber, resulting in better response. Conventional Engine
As air is controlled at the throttle valve far from the combustion chamber, it takes time to deliver necessary air
VVEL-equipped Engine
Air instantly enters when accelerator is pressed
2-2-4. Benefits of VVEL – Better Response ṲWith a short hose, water flows out right after the tap is turned (with VVEL)
without VVEL
with VVEL
2-2-5. Benefits of VVEL – Better Response ṲWith a long hose, when the tap is turned it takes a while before water flows out (without VVEL)
without VVEL
with VVEL
2-2-6. Benefits of VVEL – More Power Ṳ Torque is improved by optimized valve open-close movement,
adjusted accordingly to engine revolutions
Engine Torque
VVEL Engine
Conventional Engine
VVEL
Engine Speed
2-2-7. Benefits of VVEL – Cleaner Emissions 䂓 At timing of ignition when air is being warmed and combustion is unstable, if valve lift amount is small, air flow velocity rises. Fuel is then atomized by vaporizing effect and combustion is stabilized, resulting in clean emissions.
Valve Lift 2mm Valve Lift 8mm Average Particle Diameter 9㱘m Average Particle Diameter 157㱘m
2-2-8. Benefits of VVEL - Summary VVEL ṲVVEL is a system which controls the amount of air intake directly at the intake-valve right before the combustion chamber ṲVVEL combined with C-VTC, creates continuous movement of valve
(when throttle opening is small)
ṲVVEL throttle valve remains open, causing little pumping loss (little resistance) 䂓As valve lift amount is small, there is little friction
Better Response
ṲAllows necessary air to be sent promptly to the combustion chamber, resulting in better response
Benefits
Fuel Efficiency
More Power
Cleaner Emissions
ṲTorque is improved by optimized valve openclose movement, adjusted accordingly to engine revolutions ṲAs VVEL stabilizes combustion even when engine is cool, rise in exhaust emissions temperature enables quicker warm-up of catalyst, resulting in clean emissions
3. VVEL Structure
3-1. Basic Structure of VVEL System Nut
Ball Screw Shaft
DC Motor
Rocker Arm Control Cam
(eccentric cam)
Control Cam
(eccentric cam)
Link B
Link B Rocker Arm Control Shaft Output Cam
Control Shaft Link A Input Cam
(oscillating cam)
(eccentric cam)
Drive Shaft
Link A Drive Shaft Input Cam Output Cam
(eccentric cam)
Valve Lifter
(oscillating cam)
Valve Lifter Fragmentary View Fragmentary View (direction (direction of of arrow) arrow)
Valves
3-2. Valve Lift Amount/Operating Angle Conversion Nut
Ball Screw Shaft
DC Motor
Control Shaft
Control Shaft
Output Cam (oscillating cam)
Output Cam (oscillating cam)
Fragmentary Fragmentary View View (direction of arrow) (direction of arrow)
3-3. Valve Drive of VVEL System
Drive Shaft
Drive Shaft Valve Lifter Fragmentary Fragmentary View View (direction of arrow) (direction of arrow)
Valve Lifter Valves
3-4. VVEL Motion
Maximum Lift Amount Valve Operating Angle
Maximum Valve Lift
3-4. VVEL Motion Maximum Lift Amount
Lift Amount
Lift Amount
Minimum Valve Operating Angle
Maximum Valve Lift
Valve Operating Angle
Valve Operating Angle
Minimum Valve Lift
3-4. VVEL Motion
Lift Amount
Minimum Valve Operating Angle
Minimum Valve Lift
3-4. VVEL Motion ṲVVEL is capable of continuously changing valve lift amount (between min - max) freely
Minimum Valve Lift
Maximum Valve Lift
4. New-Generation VQ37VHR Engine
4-1ώEvaluation of the VQ Engine 䂓 VQ35HR awarded “Ward’s 10 Best Engines” for
13 consecutive years ‘95 ‘96 ‘97 ‘98 ‘99 ‘00 ‘01 ‘02 ‘03 ‘04 ‘05 ‘06 ‘07 Nissan VQ BMW I6 Ford V8 DCX V8 GM V6 Honda V6 Toyota V6
4-2. Aim of the New Generation VQ37VHR Engine 䂓 Based on the VQ35HR engine, further improvements on engine performance, fuel efficiency, and clean emissions Smooth, pleasant drive Response Response Exhilaration Exhilaration Acceleration Acceleration Sound Sound
1ὸ High rate of revolution Max 7500rpm 2ὸ Pleasant acceleration sound ԈൢὉൢὉ༓јྙỉӼɥ Clear sound 3ὸ Top level power performance in class ԈൢὉൢὉ༓јྙỉӼɥ Improved intake/exhaust/combustion Improved intake/exhaust/combustion efficiency efficiency
Fuel Fuel Efficiency Efficiency
4ὸ Increased practical fuel efficiency
Cleaner Emissions
5ὸ Best-in-class Best-in-class emission emission standard standard 5ὸ
ԈൢὉൢὉ༓јྙỉӼɥ Reduced friction
ԈൢὉൢὉ༓јྙỉӼɥ ṿṿṿṿ
4-3. Technology of VQ37VHR Engine New design for VQ37VHR Increased height of cylinder blocks
Symmetric twin intake system
Asymmetric piston skirt
Revised cylinder head
Sound insulating engine cover
Equal length exhaust manifold
Straight inlet port
Enhanced durability of rocker cover
High ignitability for iridium plug Lengthened connecting rod
Enhanced durability of chain cover High flow exhaust port Ultra-wide phase angle C-VTC on intake side
Extended amount of valve lift
VVEL system on air intake side
Enhanced valve spring Enlarged diameter of crank journal
Revised oil pump rotor
VQ37VHR
Enhanced durability of upper oil pan
Approx. 35% of parts newly developed
Enhanced durability of lower oil pan
Hydrogen-free DLC valve lifters
Enlarged diameter of crankpin
Revised diameter of valve Processing PVD piston ring Ladder frame set M12 Spark plug
Cooling water flow structure
Enhanced compression ratio
Twin knock sensor
Extended cylinder block liner
Thin-lined umbrella of intake valve
Ladder frame of cam bracket
High flow intake manifold High flow resin collector
VVEL will be debut on the SKYLINE Coupe VQ37VHR engine to be launched this fall
Thank you for your attention
