7th CIMAC CASCADES, ABB Jiangjin Turbo Systems, 2105-10-15, Hangzhou
Turbocharging T b h i S Solutions l ti ffor G Gas and d Dual-Fuel Dual Fuel Engines
Content
B i off gas engine Basics i operation ti
Turbocharging for gas and DF engine
2 stage turbocharging and variable valve timing
Summary
© ABB Group October 19, 2015
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Content
B i off gas engine Basics i operation ti
Turbocharging for gas and DF engine
2 stage turbocharging and variable valve timing
Summary
© ABB Group October 19, 2015
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Basics of Gas Engine Operation
Power
Misfiring
Operation Lines
© ABB Group October 19, 2015
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Lambda
Content
B i off gas engine Basics i operation ti
Turbocharging for gas and DF engine
2 stage turbocharging and variable valve timing
Summary
© ABB Group October 19, 2015
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Control Margin Definition 5.4 5.2 Additional comp ratio required to compensate t for f additional dditi l pressure llosses due to engine aging (i.e. DP across filters, aftercooler, etc)
Πv requiirement
5 4.8
Additional comp ratio required to operate at higher ambient temperature
46 4.6 4.4
Additional comp ratio required at ISO condition to p perform accelerations and compensate for load fluctuations
4.2
Comp ratio required at ISO condition to achieve a stable engine operation
4 3.8 Engine Required Pv
© ABB Group October 19, 2015
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Margin for operation
Margin for Ambient Temperature variation
Margin to Compensate Engine Aging
Gas Engine Control Technologies Compressor Recirculation Gas
Gas
Compressor recirculation Throttle
Receiver
Intercooler TC
In case of Premix
Power is controlled by the compressor recirculation
Power is controlled by gas injection valves
Lambda is controlled by the recirculation valve
Lambda is controlled by the Mixer
Acceleration is controlled by the Throttle
Re-circulation R i l ti h has tto b be cold ld ((after ft th the iintercooler t l tto keep efficiency high)
At full load re-circulation should be about 0
In steady state operation DP over the throttle should be 0.1- 0.3 bar (according to the control margin)
© ABB Group October 19, 2015
In case of Port Injection
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Pros
High reliability, as the control elements are operating on cold engine side
Cons
Energy dissipation in the recirculation valve and in the throttle
Gas
Gas Engine Control Technologies Waste Gate Gas Throttle Receiver
Intercooler TC
By-pass
In case of Premix
In case of Port Injection
Power is controlled by the turbine waste gate
Power is controlled by gas injection valves
Lambda is controlled by y the Mixer
Lambda is controlled by the turbine waste gate
Acceleration is controlled by the Throttle
At full load turbine by-pass flow should be about 0
In steady state operation DP over the throttle should be 0.1- 0.3 bar
At low loads the engine is controlled only by the Th ttl as there Throttle th is i no flow fl over the th WG
Pros
Cons
© ABB Group October 19, 2015
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Higher efficiency than previous previous, DP across the engine is higher than in previous case Losses in the Throttle as previous Reliability of the turbine by-pass
Gas Engine Control Technologies CR vs WG – Engine Performance Comparison 105
Varia ation of Engin ne Efficiency (%)
104
Typical gain 0.5 to 1% in engine efficiency
103 102 101 100 99 98 97 96 95
P
Compressor Recirculation
Waste Gate
P turb in for the CR case
G exchange Gas h work difference
P turb in for the WG case © ABB Group October 19, 2015
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V
Gas Engine Turbocharger Requirements
η TC
Lower Temperature & enhanced scavenging work Higher Power & higher λ
Πv
λ
Enhanced knocking margin & Combustion stability
Engine Load
© ABB Group October 19, 2015
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Gas Engine Turbocharger Requirements
Lambda
Misfiring Excess of Lambda to be depleted by the control system TC eff -5% Knocking margin
10% De-rating Knocking
Power
© ABB Group October 19, 2015
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100%
Gas Engine Turbocharger Requirements Misfiring
Lambda
More Power
More Knocking margin g
Knocking
Power
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100%
Dual Fuel Engine Gas vs Diesel Requirements Gas
Waste Gate
E i C Engine Compression i Ratio Miller Timing
© ABB Group October 19, 2015
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Diesel
To control lambda (port injected engines)
No need to control
To compensate ambient variations
No need to control
Always operated
Always closed as it could be fouled by soot if operated
To control λ during engine acceleration
No need to control
The highest possible without knocking
Highest possible. A minimum value is necessary to ensure stable combustion at all loads
The most advanced the better. Limits apply to ignitability of pilot fuel
The most advanced the better. Limits apply due to ignitability of fuel
Dual Fuel Engine Performance Requirements Engine data
Diesel fixcam
Diesel VVT
P max [bar] [b ]
Gas fixcam
Gas VVT
Fi d for Fixed f allll cases
Lambda at full load
2.40
2.20
2.20
2.20
Engine Compression ratio
CR
CR+1.5
CR
CR+1.5
EVO/EVC/IVO/IVC Valve timing EVO/EVC/IVO/IVC
IVC-30
IVC
IVC-30
Waste gate position gas mode
always close
none
open all loads
open all loads
Engine control tool in gas mode
N/A
N/A
Waste gate
Waste gate
P Pscav (b ) (bar)
5 20 5.20
5 20 5.20
4 70 4.70
5 00 5.00
TTI (°C)
517
538
545
523
TC efficiency
65.7%
66.9%
68.0%
67.5%
E Eng.efficiency ffi i
43 8% 43.8%
44 9% 44.9%
46 2% 46.2%
47 6% 47.6%
© ABB Group October 19, 2015
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Content
B i off gas engine Basics i operation ti
Turbocharging for gas and DF engine
2 stage turbocharging and variable valve timing
Summary
© ABB Group October 19, 2015
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Two-stage Turbocharging How It Works T
2-stage compression work k
© ABB Group October 19, 2015
1-stage compression work
S Intercooling is the key factor to make two-stage more efficient than single stage The higher the intercooling the higher the Turbocharging efficiency, but there are limits …
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2-stage Turbocharging Control Possibility HP+LP Bypass HP Bypass
LP Bypass
Gas Throttle Receiver
Intercooler Intercooler
HP TC
LP TC
HP Wastegate
LP Wastegate HP - LP Wastegate
Most popular solution © ABB Group October 19, 2015
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Gas
Variable Valve Timing Valve Control Management
© ABB Group October 19, 2015
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Valve Management Control Valve Lift Profile Capabilities
© ABB Group October 19, 2015
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Advanced Miller Cycle – Power2 & VCM – Gas Engine Performance comparison 1
1-stage with WG + TV
22 bar bmep
1-stage with VTG + TV
22 bar bmep
2 t 2-stage with ith hpt h t WG + TV
22 b bar bmep b
2-stage with hpt WG + TV
24 bar bmep
2 t 2-stage with ith hpt h t WG + TV + VVT for f 2-stage 2 t
24 bar b bmep b
2-stage with hpt WG + VVT for 2-stage layout y p point 50% load
24 bar bmep
2-stage with hpt WG + VVT for 2-stage layout point 25% load
24 bar bmep
2-stage VCM
WG = wastegate; TV = throttle valve; VVT = variable valve timing
© ABB Group October 19, 2015
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Advanced Miller Cycle – Power2 & VCM – Gas Engine Performance comparison 2 –Gas Gas Exchange Work
2-stage with VCM
Gas exch work (b bar)
2-stage with VVT and WG controlled
1-stage WG controlled
0.1 bar
1 bar
BMEP (bar) © ABB Group October 19, 2015
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Advanced Miller Cycle – Power2 & VCM – Gas Engine Performance comparison 3 – Engine efficiency gain 5 4.5 1.1%
Engine Effficiency Ga ains (%pointts )
4
3.5 3 1 5% 1.5%
2.5 2
1.5 1
05 0.5 0 1-stage WG controlled
© ABB Group October 19, 2015
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2-stage with VVT and WG controlled
2-stage with VCM
Advanced Miller Cycle – Power2 & VCM – DF Engine Performance comparison Engine data
1-stage
Power2+EWG
Power2 + EWG+VVT
Power2+ VCM
Valve timing
Miller
Miller
Moderate Miller with 2 positions VVT
Advanced Miller VCM controlled
EVO/EVC/IVO/IVC Valve timing IVC
IVC-2
Waste gate position gas mode Waste gate position diesel mode
Gas: IVC-38 / IVC-30 Diesel: IVC-40 / IVC
open all loads
none
open full load / close elsewhere
none
Exhaust gas waste gate
Engine control tool
IVC-25 / IVC-10
HP Turbine by-pass
Engine efficienc cy Gaines [%]
3 2.5 2 15 1.5 1 0.5 0 © ABB Group October 19, 2015
1-stage + WG | Slide 23
2-stage +WG Gas
2-stage +WG + 2-stage +VCM VVT Diesel
VCM
Content
B i off gas engine Basics i operation ti
Turbocharging for gas and DF engine
2 stage turbocharging and variable valve timing
Summary
© ABB Group October 19, 2015
| Slide 24
Conclusions
Gas engines require an higher control level than their correspondent diesel versions i
Dual-fuel engines need to overcome the design compromise in order to operate p with comparable p efficiency y in both modes.
Proper engine operation requires a degree of turbocharging flexibility in order to cope with different requirements.
High performance engines require advanced turbocharging solutions like: High compression ratios High efficiency Variable valve timing
ABB can provide all the required solutions: 1-stage: stage A100 00 2-stage: Power2 (comp. ratio up to 12 and TC efficiency beyond 75%) Variable valve timing: VCM
© ABB Group October 19, 2015
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The Power of Power2 …
© ABB Group / ABB Turbocharging October 19, 2015 | Slide 26 | filename