Episode #5: Electronic Fuel Injection
Jay Leno’s Tank Car is just one of several high profile development programs ongoing in the Banks Advanced Prototype Engineering labs.
Part Five in a Series: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8
One of the Banks Sidewinder Duramax Diesel race trucks can be seen in the background. At this point in the Tank Car’s transformation, all of the fabricated intake components and the fuel rails were sent out to be polished.
While the intake and exhaust manifold work was being completed, another team of Banks engineers and technicians was coordinating the development of the electronic fuel injection system. Bosch came on board and supplied all of the components needed to do the conversion along with technical support. Although many of these were off-the-shelf items, a lot of work was needed to adapt them to the AV 1790 engine. Here Test Engineer Chuck Swart installs one of several custom wire looms the Banks team made up to connect the various EFI sensors.
The heart of the EFI system is this Bosch MS 2.9.1 engine management controller. Don’t go looking for one of these at your local Mercedes dealer, you won’t find it. It’s Formula One issue from the Bosch Motorsport program and Jay got the only spare unit available in the US. We mounted the controller under the dash with bulkhead cable connectors through the firewall to protect this priceless processor. The unique bracket turned out so nicely that it was a shame to hide it under the dash.
The Bosch EFI system senses crank, cam, and throttle position, engine speed, intake air temperature and pressure, fuel temperature and pressure, oil temperature and air/fuel ratio. Because the AV 1790 is air-cooled, engine temperature is monitored through this Bosch oil temperature sensor we installed above the oil filter.
A trigger wheel and proximity sensor are used to relate the crank and cam positions to the timing of the injection event. The Banks team designed and machined this trigger ring and adapter flange to mount on the crank stub shaft in the accessory gear case at the front of the engine. A billet aluminum gear cover with an integral boss was machined to position the proximity sensor in line with the trigger ring.
The cam position sensor likewise required a trigger wheel. The camshafts on the AV 1790 V12 are driven by a pair of intermediate shafts and right-angle spur gears at the front of each cam. In this case we modified the existing left-side gear cover to accept a sensor, and machined a trigger wheel to indicate the No. 1 cylinder position.
Twin oxygen sensors will sample the spent gasses from combustion at the inlet to each turbocharger and adjust the air/fuel ratio based on throttle position, RPM, temperature, and other engine conditions.
During the initial tuning process, we’ll use thermocouple pyrometers to indicate the exhaust temperature for each of the twelve cylinders. These leads will connect to a data logger that displays the temperatures on a bar graph. The Bosch MS 2.9.1 EFI controller can tailor injector delivery for individual cylinders so we can adjust the exhaust temperature in each cylinder.
Hey, All the polished stuff is back! Next time we’ll start the assembly and installation of the fuel system, and maybe start installing some of this shiny stuff on the engine.
Read more! Episode 6