Propane Engine Research Articles

Fundamental Study for Applying a Propane Gas Injection System in a Small-Ship Engine

As a response to stricter exhaust emission regulations, an increasing number of diesel-powered ships are switching to liquefied natural gas (LNG) fuel or installing post-processing devices to reduce exhaust gas. However, these methods are not feasible for small ships operating primarily along the coast. This is because the cost of the exhaust gas post-processing devices is high, while a large-volume fuel system is required in the case of LNG. Thus, this study used a propane gas fuel system based on a 5.0 L gasoline engine for easy application to existing small ships without major modifications. To optimize the control according to changes in the fuel system, a 1D simulation was performed on the engine to be developed, and ignition timing optimization was investigated. In addition, fuel consumption was compared with that of a gasoline-based engine. The propane engine achieved over 95% power in comparison to a gasoline-based engine. During cold-start tests, starting performance at −15 °C was ensured. The purpose of this study is to provide guidelines to assist the development of LPG or propane engines based on gasoline engines through these processes.

Evaluation of kinetics mechanisms ability to predict natural gas reactivity using a fuel substitution method

Previous homogeneous-charge compression-ignition engine fuel substitution experiments1 were used to test the performance of five different chemical kinetics mechanisms for natural gas fuels. A two-zone model was used to simulate the engine experiments using the five mechanisms tested. Simulations of engine experiments for six distinct operating conditions using based fuel mixtures of methane/hydrogen and methane/propane were performed along with simulations of fuel substitution sweeps with fixed boundary conditions using hydrogen, ethane, ethylene, propane, and n-butane as test fuels. The simulation results were used to quantify the ability of mechanisms to predict both the absolute reactivity of the reference fuels and the reactivity of the test fuels relative to the reference fuels using two metrics: required temperature at intake valve closure (IVC) with fixed fuel concentrations and required reference fuel concentrations with fixed IVC temperature. The five mechanisms used for this study showed substantially different results, most notably related to their propane chemistry. Simulations using the LLNL mechanism resulted in the closest match to propane engine test results, while the Aramco and C5-49 mechanisms showed some disagreement, and the GRI and UBC mechanisms showed much larger discrepancies. Simulations with all five mechanisms showed good agreement with hydrogen engine test results.

Variable-mixture-ratio and other rocket engines for advanced shuttles

Previous computer models of rocket engines and single-stage-to-orbit vehicles have been extended to include variable-mixture-ratio engines. The model has been applied to study a vertical-takeoff, horizontal-landing, winged, manned, fully-reusable vehicle with a payload of 13.6 Mg and which is launched to low-earth orbit. Both single-stage and two-stage vehicles are considered, with special attention given to hydrogen, methane, and propane engines with staged-combustion cycles. Results are presented for the optimum nozzle exit pressure, thrust split between the booster and orbiter, chamber pressure, and mixture ratio.

A comparison of gasoline, methanol and propane on S.I. Engine performances.

Methanol has emerged as a near-term alternative to hydro-carbon fuel. On the one hand, in Japan, LPG fuel has been utilized for the Taxi as an alternate to gasoline in respect of economy. This paper reports a comparison of methanol and propane as LPG fuel to base gasoline on S. I. engine performance. The results obtained are as follows: (1) the compression ratio is as high as 12:1; the maximum methanol and propane engine output is higher by approximately 20% and 8% respectively than the base gasoline engine. (2) brake thermal efficiency of the methanol and propane engine is better than the base gasoline engine, but the difference becomes smaller as the engine output becomes lower. (3) engine out emission level of methanol fuel are lower than gasoline, especially for NOx and THC; but the NOx level of propane fuel is higher than that for gasoline.