Mazda's Diesel & old Marine Corps contract
#1
08-23-2007, 08:01 AM
Mazda's Diesel & old Marine Corps contract
One of the lesser known chapters in Diesel engine history
is that the US Marine Corps put out a contract several years ago
to create a 'rotary diesel' similar to the Wankel engine used in the Mazda RX7.
I believe the Marines expected Ford to win this research and have Mazda do the work, but instead a small US company named RPI under-bid Ford and got the rotary diesel contract. Unfortunately the research to build this Wankel Diesel failed and the Marines abandoned the project.
However, the article from Australia below shows that Mazda 'does do diesels' and is an indicator of how state of the art they can do:
===
http://autoweb.drive.com.au/cms/A_10...wsarticle.html
sample quote:
Relatively low combustion ratio
The MZR-CD’s low compression ratio (16.7 to 1) allows low-temperature pilot premixed combustion, also reducing soot and NOx emissions.
Fuel is injected into each combustion chamber before the piston reaches top dead centre, promoting combustion efficiency while minimising production of particulate matter or black soot. In addition, the lower combustion temperature helps to minimise NOx.
To enable optimal control of the air/fuel ratio, a high response intake shutter valve and a valve to control the recirculation rate from the exhaust gas recirculation (ERG) cooler are located on the intake side of the engine. Residual oxygen in the exhaust gases is monitored by an O2 sensor and this information is utilised by a 32-bit powertrain control module to optimise the fuel/air ratio, continuously optimising the mix and suppressing NOx.
A catalysed diesel particulate filter reduces black smoke emissions to virtually zero by capturing particulate matter in a ceramic filter. When a specific quality of particulate matter is trapped it is automatically burnt off, allowing the filter to return to its original efficiency.
The particulate filter enables the MZR-CD engine to cut its soot emissions to 80 per cent below the Euro Stage IV emission standard.
The relatively low compression ratio also reduces pumping loss and promotes thermal efficiency. Typically a low compression ratio means inferior thermal efficiency under low-load conditions, but this is offset by a combination of high fuel injection pressure and the frequency and timing of the multi-stage injections.
These attributes produce not only 360Nm of torque but combine with the tall gear ratios provided by the Mazda3 Diesel’s six-speed manual gearbox to produce impressive fuel economy numbers.
Variable Geometry Turbocharger
The engine also features a variable-geometry turbocharger that has a lower inertia moment and features a short distance between the exhaust gas inlet and the centre of the turbine shaft.
A variable-geometry turbocharger helps maximise torque over the widest range of engine speeds. The Mazda3’s VGT is an update of earlier designs with the size of the turbine reduced to lower the inertia moment by 14 per cent. In addition the ratio between the cross sectional area of the narrowest part of the VGT’s exhaust gas inlet and the distance from the centre of that area to the centre of the turbine shaft has been reduced, producing smoother acceleration, a 10 per cent power jump, a 10 per cent improvement in maximum torque and better fuel economy.
The variable-geometry turbocharger is combined with the engine’s high pressure common-rail fuel injection system, with optimised injection volume and multi-stage injection of up to nine times per cycle, and a relatively low compression ratio, all of which improve output and torque, repress combustion noise and reduce emissions.
High torque, low NVH
The new turbocharged 2.0-litre MZR-CD engine has been developed to deliver high torque while minimising noise, vibration and harshness (NVH).
Multi-stage injection, which is performed up to nine times per cycle, prevents overly rapid pressure increase in the cylinders, suppressing diesel knock and other combustion noise.
When the engine is idling the intake shutter valve restricts air intake volume to reduce cylinder pressure by about 25 per cent and suppresses idle knock, while the low compression ratio limits engine speed fluctuations and significantly lowers vibration.
is that the US Marine Corps put out a contract several years ago
to create a 'rotary diesel' similar to the Wankel engine used in the Mazda RX7.
I believe the Marines expected Ford to win this research and have Mazda do the work, but instead a small US company named RPI under-bid Ford and got the rotary diesel contract. Unfortunately the research to build this Wankel Diesel failed and the Marines abandoned the project.
However, the article from Australia below shows that Mazda 'does do diesels' and is an indicator of how state of the art they can do:
===
http://autoweb.drive.com.au/cms/A_10...wsarticle.html
sample quote:
Relatively low combustion ratio
The MZR-CD’s low compression ratio (16.7 to 1) allows low-temperature pilot premixed combustion, also reducing soot and NOx emissions.
Fuel is injected into each combustion chamber before the piston reaches top dead centre, promoting combustion efficiency while minimising production of particulate matter or black soot. In addition, the lower combustion temperature helps to minimise NOx.
To enable optimal control of the air/fuel ratio, a high response intake shutter valve and a valve to control the recirculation rate from the exhaust gas recirculation (ERG) cooler are located on the intake side of the engine. Residual oxygen in the exhaust gases is monitored by an O2 sensor and this information is utilised by a 32-bit powertrain control module to optimise the fuel/air ratio, continuously optimising the mix and suppressing NOx.
A catalysed diesel particulate filter reduces black smoke emissions to virtually zero by capturing particulate matter in a ceramic filter. When a specific quality of particulate matter is trapped it is automatically burnt off, allowing the filter to return to its original efficiency.
The particulate filter enables the MZR-CD engine to cut its soot emissions to 80 per cent below the Euro Stage IV emission standard.
The relatively low compression ratio also reduces pumping loss and promotes thermal efficiency. Typically a low compression ratio means inferior thermal efficiency under low-load conditions, but this is offset by a combination of high fuel injection pressure and the frequency and timing of the multi-stage injections.
These attributes produce not only 360Nm of torque but combine with the tall gear ratios provided by the Mazda3 Diesel’s six-speed manual gearbox to produce impressive fuel economy numbers.
Variable Geometry Turbocharger
The engine also features a variable-geometry turbocharger that has a lower inertia moment and features a short distance between the exhaust gas inlet and the centre of the turbine shaft.
A variable-geometry turbocharger helps maximise torque over the widest range of engine speeds. The Mazda3’s VGT is an update of earlier designs with the size of the turbine reduced to lower the inertia moment by 14 per cent. In addition the ratio between the cross sectional area of the narrowest part of the VGT’s exhaust gas inlet and the distance from the centre of that area to the centre of the turbine shaft has been reduced, producing smoother acceleration, a 10 per cent power jump, a 10 per cent improvement in maximum torque and better fuel economy.
The variable-geometry turbocharger is combined with the engine’s high pressure common-rail fuel injection system, with optimised injection volume and multi-stage injection of up to nine times per cycle, and a relatively low compression ratio, all of which improve output and torque, repress combustion noise and reduce emissions.
High torque, low NVH
The new turbocharged 2.0-litre MZR-CD engine has been developed to deliver high torque while minimising noise, vibration and harshness (NVH).
Multi-stage injection, which is performed up to nine times per cycle, prevents overly rapid pressure increase in the cylinders, suppressing diesel knock and other combustion noise.
When the engine is idling the intake shutter valve restricts air intake volume to reduce cylinder pressure by about 25 per cent and suppresses idle knock, while the low compression ratio limits engine speed fluctuations and significantly lowers vibration.
#3
08-24-2007, 06:57 AM
RE: Mazda's Diesel & old Marine Corps contract
I think it was in the life of the lip seals at the ends of the triangular rotors
but I don't have a clear memory.
I did a quick search on Google with RPI and 'rotary diesel'
and these links:
http://rotarynews.com/node/view/461
http://www.theautochannel.com/news/2...09/148812.html
but I don't have a clear memory.
I did a quick search on Google with RPI and 'rotary diesel'
and these links:
http://rotarynews.com/node/view/461
http://www.theautochannel.com/news/2...09/148812.html