Bi-Fuel Kits in detail
Bi-Fuel Kit Powered by GTI Altronic are available for all Hipower Generators in Rental and Standby configuration.
HIPOWER BI-FUEL SYSTEMS are available in Standby Generators as well as for Prime Power and Rental Applications. BI-FUEL SYSTEMS capitalize on revolutionary technology that enables diesel engines to run on a gas/diesel mixture where natural (methane-based) gas accounts for up to 70% of the total fuel requirement. This solution substantially reduces operating costs and lowers emissions forengine owners, reducing diesel fuel purchase requirements by up to 50%. The savings are so significant that some operators report saving $1 million per year, or more, compared to burning only diesel fuel.
A key feature of the GTI BI-FUEL system is the controller module’s ability to fine-tune the fuel mixture for optimal performance and savings automatically or on command from the operator. This feature gives companies the flexibility to choose between gas and diesel modes as dictated by fuel pricing, fuel availability and other considerations.
Running at 40% to 90% of rated load, engines equipped with a bi-fuel system generally will accept gas at a substitution rate for diesel in the range of 50% to 90%. Regardless of the maximum that can be achieved, Altronic limits the substitution to 70% in order to maintain combustion stability, safety margin, adequate lubricity of the diesel injectors, and to preserve the required authority of the diesel governor to react to load changes. Customers should always be cautious of claims of guaranteed substitution rates. The achievable level is dictated by a number of factors. These include gas quality, engine design and mechanical condition, ambient temperature, etc. All of Altronic’s literature indicates substitution rates “up to” 70%.
In this load range, the standard Altronic GTI Bi-Fuel® system is “dynamic” in its ability to respond to load changes, as the amount of fuel drawn into the engine is determined by the vacuum signal of the turbo, which is proportional to engine load. As a result, the use of “dynamic” to describe additional fuel control valves and strategies is misleading.
The Altronic GTI Bi-Fuel® system is a zero pressure based fuel supply design, or “draw-through.” This is to say that gas in not pressurized or pushed into the intake. Instead, it is pulled in by the vacuum signal of the turbo inlet, which is proportional to engine load. Systems that run at a positive fuel pressure rely on other engine/governor signals and control software to determine the amount of gas required at any given load point. These systems are far more vulnerable to over-fueling conditions that can lead to engine detonation due to inadequate response time, system failure modes, or sudden decreases in engine load.
Draw-through systems, where the gas is supplied at atmospheric or at slight vacuum, as described above, result in greater pressure drop between the outlet of the gas train and the gas mixer. With improper or inadequate application knowledge, this pressure drop can become the limiting factor in the achievable substitution rate. In many cases, once this limit is reached, additional substitution can sometimes be achieved by adjusting the zero governor (regulator) outlet pressure. This is results in the supply pressure going positive, with possible consequences as described above. Altronic policy strictly forbids this practice in our aftermarket product. We have overcome this limitation with careful re-sizing of the downstream components.
The basic GTI system is designed for simplicity. Unlike some of its competitors, the GTI system does not connect or integrate into the diesel engine controls or governor. Some systems endeavor to control both the gaseous and diesel fuels. The design philosophy of the aftermarket GTI system is to keep them separate, and allow the diesel governor to remain independent. We believe that the diesel fuel should take the lead role in reacting to changes in load, and the gas fuel system should follow the resulting turbo vacuum signal. Control of both the gas and diesel fuel systems is complicated and runs the risk of the two systems fighting each other and putting the safety of the engine in jeopardy.
The GTI Altronic kit is available for Hipower Generators Models HYW-20, HYW-25, HYW-35, HYW-45, HRYW 25, HRYW 40, HRYW 50, HJW 55, HJW 65, HJW-85, HJW-105, HRJW-60, HRJW-75, HRJW 105, HJW-130, HJW-155, HJW-185, HJW-205, HJW 225, HJW-275, HRJW-145, HRJW-175, HRJW 205, HRJW- 235, HRJW 310, HFW-130, HFW-160, HFW-180, HFW 200, HFW-230, HFW-250, HFW-300 T6, HFW-345, HFW 350 T6, HMW-810, HMW-915, HMW-1020, HRMW-1150, HMW-1205, HMW-1550, HMW-1730, HMW-1975 and HMW-2230.
The GTI system is designed to measure a number of critical parameters of the gas supply system and engine operation in bi-fuel mode. One of the most important concerns of operating a diesel engine on gas is detonation. An engine that operates on pure diesel, by its nature, is not terribly vulnerable to this condition. However, the introduction of a gaseous fuel does increase this risk. The parameters measured by the GTI control system—combined with proper set points and commissioning procedures—are designed to prevent the conditions that can result in detonation. However, the ultimate line of defense is the incorporation of sensors to detect the presence of detonation so the controls can shut off the gas supply before damage occurs.
Since diesel engines are not equipped with such sensors, they are included as part of the GTI Bi-Fuel® kit. Altronic believes in the use of vibration sensors to serve this purpose. Some of our competitors do not include any sort of sensor, and instead choose to rely on the ability of the operator to avoid conditions of detonation. This strategy is risky, and in several known cases has resulted in severe engine damage. Other competitors use actual detonation detection systems. Altronic actually designs and manufactures a line of detonation detection systems for gas-fueled industrial engines, and so it not only has access to such systems, but also has a great deal of expertise. Even so, Altronic has chosen vibration sensors rather than detonation detection for use in its GTI systems.
Detonation systems are designed to filter out and ignore all frequencies except for the small band in which detonation occurs. This requires a great deal of expertise on the part of the commissioning technician who verifies the system calibration by actually inducing light detonation (incipient knock), something that is not easy to do on a diesel engine. Failure to achieve the correct setting leaves the engine with no effective means of protection. The use of vibration sensors greatly simplifies this process by simply detecting vibration above the pure diesel baseline. As an added benefit, the system will detect changes in vibration that can result from excess mechanical wear and failure.